Associate Chair Clinical Research, Dept of Pediatrics (2012 - Present)
DrPH, UC Berkeley, Epidemiology (1986)
Primary research interests include 1) epidemiology of birth defects, 2) gene-environment approaches to perinatal outcomes, and 3) nutrition and reproductive outcomes.
To examine associations with morbidly adherent placenta (MAP) among women with placenta previa.Women with MAP (cases) and previa alone (controls) were identified from a cohort of 236 714 singleton pregnancies with both first and second trimester prenatal screening, and live birth and hospital discharge records; pregnancies with aneuploidies and neural tube or abdominal wall defects were excluded. Logistic binomial regression was used to compare cases with controls.In all, 37 cases with MAP and 699 controls with previa alone were included. Risk for MAP was increased among multiparous women with pregnancy-associated plasma protein-A (PAPP-A) ⩾95th percentile (⩾2.63 multiple of the median (MoM); adjusted OR (aOR) 8.7, 95% confidence interval (CI) 2.8 to 27.4), maternal-serum alpha fetoprotein (MS-AFP) ⩾95th percentile (⩾1.79 MoM; aOR 2.8, 95% CI 1.0 to 8.0), and 1 and ⩾2 prior cesarean deliveries (CDs; aORs 4.4, 95% CI 1.5 to 13.6 and 18.4, 95% CI 5.9 to 57.5, respectively).Elevated PAPP-A, elevated MS-AFP and prior CDs are associated with MAP among women with previa.
View details for DOI 10.1038/jp.2015.40
View details for PubMedID 25927270
We sought to identify age group specific maternal risk factors for gastroschisis. Maternal characteristics and prenatal factors were compared for 1,279 live born infants with gastroschisis and 3,069,678 without. Data were obtained using the California database containing linked hospital discharge, birth certificate and death records from 1 year prior to the birth to 1 year after the birth. Backwards-stepwise logistic regression models were used with maternal factors where initial inclusion was determined by a threshold of p < 0.10 on initial crude analyses. Due to the strong association of gastroschisis with young maternal age, models were stratified by age groups and odds ratios were calculated. These final models identified maternal infection as the only risk factor common to all age groups and a protective effect of obesity and gestational hypertension. In addition, age specific risk factors were identified. Although gestation at the time of infection was not available, a sexually transmitted disease complicating pregnancy was associated with increased risk in the less than 20 years of age grouping whereas viral infection was associated with increased risk only in the 20-24 and more than 24 years of age groupings. Urinary tract infection remained in the final logistic model for women less than 20 years. Short interpregnancy interval was not found to be a risk factor for any age group. Our findings support the need to explore maternal infection by type and gestational timing. © 2015 Wiley Periodicals, Inc.
View details for DOI 10.1002/ajmg.a.37016
View details for PubMedID 25913847
This study aims to evaluate the relationship between early-onset severe preeclampsia and first trimester serum levels of pregnancy-associated plasma protein A (PAPP-A) and total human chorionic gonadotropin (hCG).The association between early-onset severe preeclampsia and abnormal levels of first trimester PAPP-A and total hCG in maternal serum were measured in a sample of singleton pregnancies without chromosomal defects that had integrated prenatal serum screening in 2009 and 2010 (n = 129,488). Logistic binomial regression was used to estimate the relative risk (RR) of early-onset severe preeclampsia in pregnancies with abnormal levels of first trimester PAPP-A or total hCG as compared with controls.Regardless of parity, women with low first trimester PAPP-A or high total hCG were at increased risk for early-onset severe preeclampsia. Women with low PAPP-A (multiple of the median [MoM] ≤ the 10th percentile in nulliparous or ≤ the 5th percentile in multiparous) or high total hCG (MoM ≥ the 90th percentile in nulliparous or ≥ the 95th percentile in multiparous) were at more than a threefold increased risk for early-onset severe preeclampsia (RR, 4.2; 95% confidence interval [CI], 3.0-5.9 and RR, 3.3; 95% CI, 2.1-5.2, respectively).Routinely collected first trimester measurements of PAPP-A and total hCG provide unique risk information for early-onset severe preeclampsia.
View details for DOI 10.1055/s-0034-1396697
View details for Web of Science ID 000355418600014
View details for PubMedID 25519199
Despite years of research, the etiologies of preterm birth remain unclear. In order to help generate new research hypotheses, this study explored spatial and temporal patterns of preterm birth in a large, total-population dataset.Data on 145 million US births in 3,000 counties from the Natality Files of the National Center for Health Statistics for 1971-2011 were examined. State trends in early (<34 wk) and late (34-36 wk) preterm birth rates were compared. K-means cluster analyses were conducted to identify gestational age distribution patterns for all US counties over time.A weak association was observed between state trends in <34 wk birth rates and the initial absolute <34 wk birth rate. Significant associations were observed between trends in <34 wk and 34-36 wk birth rates and between white and African American <34 wk births. Periodicity was observed in county-level trends in <34 wk birth rates. Cluster analyses identified periods of significant heterogeneity and homogeneity in gestational age distributional trends for US counties.The observed geographic and temporal patterns suggest periodicity and complex, shared influences among preterm birth rates in the United States. These patterns could provide insight into promising hypotheses for further research.
View details for DOI 10.1038/pr.2015.55
View details for Web of Science ID 000354755000017
View details for PubMedID 25760546
Gastroschisis is a birth defect where loops of bowel are protruding from the abdominal wall at birth. Previous research has suggested that gastroschisis cases can occur in clusters. The objective of this study was to identify if there were areas of elevated gastroschisis risk using data from the National Birth Defects Prevention Study (NBDPS), 1997 through 2007.We obtained data on cases (n = 371) through population-based birth defects surveillance systems in Arkansas, California, and Utah; controls (n = 2359) were selected from the same geographic areas as cases. Mothers were interviewed on demographic information and exposures during pregnancy, including residential history. We used first trimester maternal addresses and generalized additive models to create a continuous map surface of odds ratios (OR) by smoothing over latitude and longitude. Permutation tests were used to assess whether location of maternal residence was important and identify locations with statistically significant ORs.In Arkansas, adjusted ORs in the southwest corner were 2.0 and the global deviance was not statistically significant (p-value: 0.57). Adjusted ORs for California indicated areas of increased risk with ORs 1.3 (p-value: 0.34). In Utah, the adjusted ORs were elevated (OR: 2.4) in the south-eastern corner of the study area (p-value: 0.34).The results of this study, while not statistically significant, suggest there were spatial variations in gastroschisis births. We cannot rule out that these variations were due to edge effects or residual confounding. Birth Defects Research (Part A) 103:544-553, 2015. © 2015 Wiley Periodicals, Inc.
View details for DOI 10.1002/bdra.23375
View details for Web of Science ID 000356674800010
View details for PubMedID 25850424
Estrogenic endocrine disruptors acting via estrogen receptors α (ESR1) and β (ESR2) have been implicated in the etiology of hypospadias, a common congenital malformation of the male external genitalia. We determined the association of single nucleotide polymorphisms in ESR1 and ESR2 genes with hypospadias in a racially/ethnically diverse study population of California births.We investigated the relationship between hypospadias and 108 ESR1 and 36 ESR2 single nucleotide polymorphisms in 647 cases and 877 population based nonmalformed controls among infants born in selected California counties from 1990 to 2003. Subgroup analyses were performed by race/ethnicity (nonHispanic white and Hispanic subjects) and by hypospadias severity (mild to moderate and severe).Odds ratios for 33 of the 108 ESR1 single nucleotide polymorphisms had p values less than 0.05 (p = 0.05 to 0.007) for risk of hypospadias. However, none of the 36 ESR2 single nucleotide polymorphisms was significantly associated. In stratified analyses the association results were consistent by disease severity but different sets of single nucleotide polymorphisms were significantly associated with hypospadias in nonHispanic white and Hispanic subjects. Due to high linkage disequilibrium across the single nucleotide polymorphisms, haplotype analyses were conducted and identified 6 haplotype blocks in ESR1 gene that had haplotypes significantly associated with an increased risk of hypospadias (OR 1.3 to 1.8, p = 0.04 to 0.00001). Similar to single nucleotide polymorphism analysis, different ESR1 haplotypes were associated with risk of hypospadias in nonHispanic white and Hispanic subjects. No significant haplotype association was observed for ESR2.The data provide evidence that ESR1 single nucleotide polymorphisms and haplotypes influence the risk of hypospadias in white and Hispanic subjects, and warrant further examination in other study populations.
View details for DOI 10.1016/j.juro.2014.11.087
View details for Web of Science ID 000353113200073
View details for PubMedID 25463985
The purpose of this study was to compare the performance of first-trimester nuchal translucency (NT) cutoff of ≥3.5 mm with NT percentiles that were calculated for crown-rump length to identify fetuses with critical congenital heart defects (CCHDs).This was a population-level study of singleton pregnancies in California with NT measurements performed between 11 and 14 weeks of gestation. Eligible cases were those that resulted in live births from 2009-2010 and had information about the presence or absence of CCHDs available in the hospital discharge records through age 1 year (n = 76,089). Logistic binomial regression methods were used to compare the rate of CCHDs by an NT percentile for crown-rump length and millimeter cutpoints.Compared with fetuses with an NT measurement of <90th percentile, fetuses with an NT of ≥99th percentile were >5 times as likely to have a CCHD (1.3% vs 0.2%; relative risk, 5.66; 95% confidence interval, 3.19-10.04) and fetuses with an NT measurement ≥3.5 mm were >12 times as likely to have a CCHD (2.8% vs 0.2%; relative risk, 12.28; 95% confidence interval, 5.11-29.51). NT ≥99th percentile had a sensitivity of 5.8% and a specificity of 98.9% for the detection of CCHDs compared with 2.6% and 99.8% for NT ≥3.5 mm.Results show that NT measurements of ≥99th percentile and ≥3.5 mm are not equivalent and that substantial risk for CCHD extends to the less restrictive ≥99th percentile cutpoint. Data suggest that the use of this cutpoint compared with the current standard could double the number of CCHDs that are identified based on NT risk.
View details for DOI 10.1016/j.ajog.2014.10.1102
View details for Web of Science ID 000352147100029
View details for PubMedID 25448520
We used exome sequencing to study a non-consanguineous family with two children who had anterior segment dysgenesis, sclerocornea, microphthalmia, hypotonia and developmental delays. Sanger sequencing verified two Peroxidasin (PXDN) mutations in both sibs--a maternally inherited, nonsense mutation, c.1021C>T predicting p.(Arg341*), and a paternally inherited, 23-basepair deletion causing a frameshift and premature protein truncation, c.2375_2397del23, predicting p.(Leu792Hisfs*67). We re-examined exome data from 20 other patients with structural eye defects and identified two additional PXDN mutations in a sporadic male with bilateral microphthalmia, cataracts and anterior segment dysgenesis--a maternally inherited, frameshift mutation, c.1192delT, predicting p.(Tyr398Thrfs*40) and a paternally inherited, missense substitution that was predicted to be deleterious, c.947 A>C, predicting p.(Gln316Pro). Mutations in PXDN were previously reported in three families with congenital cataracts, microcornea, sclerocornea and developmental glaucoma. The gene is expressed in corneal epithelium and is secreted into the extracellular matrix. Defective peroxidasin has been shown to impair sulfilimine bond formation in collagen IV, a constituent of the basement membrane, implying that the eye defects result because of loss of basement membrane integrity in the developing eye. Our finding of a broader phenotype than previously appreciated for PXDN mutations is typical for exome-sequencing studies, which have proven to be highly effective for mutation detection in patients with atypical presentations. We conclude that PXDN sequencing should be considered in microphthalmia with anterior segment dysgenesis.
View details for DOI 10.1038/ejhg.2014.119
View details for PubMedID 24939590
Several single-nucleotide variants (SNVs) in low-density lipoprotein receptor-related protein 6 (Lrp6) cause neural tube defects (NTDs) in mice. We therefore examined LRP6 in 192 unrelated infants from California with the NTD, spina bifida, and found four heterozygous missense SNVs, three of which were predicted to be deleterious, among NTD cases and not in 190 ethnically matched nonmalformed controls. Parents and siblings could not be tested because of the study design. Like Crooked tail and Ringleschwanz mouse variants, the p.Tyr544Cys Lrp6 protein failed to bind the chaperone protein mesoderm development and impaired Lrp6 subcellular localization to the plasma membrane of MDCK II cells. Only the p.Tyr544Cys Lrp6 variant downregulated canonical Wnt signaling in a TopFlash luciferase reporter in vitro assay. In contrast, three Lrp6 mutants (p.Ala3Val, p.Tyr544Cys, and p.Arg1574Leu) increased noncanonical Wnt/planar cell polarity (PCP) signaling in an Ap1-luciferase assay. Thus, LRP6 variants outside of YWTD repeats could potentially predispose embryos to NTDs, whereas Lrp6 modulation of Wnt/PCP signaling would be more essential than its canonical pathway role in neural tube closure.
View details for DOI 10.1002/humu.22750
View details for Web of Science ID 000351399900010
View details for PubMedID 25546815
Bronchopulmonary dysplasia (BPD) remains a serious morbidity in very low-birth-weight (VLBW) infants (<1500 g). Deregionalization of neonatal care has resulted in an increasing number of VLBW infants treated in community hospitals with unknown impact on the development of BPD.To identify individual risk factors for BPD development and hospital variation of BPD rates across all levels of neonatal intensive care units (NICUs) within the California Perinatal Quality Care Collaborative.Retrospective cohort study (January 2007 to December 2011) from the California Perinatal Quality Care Collaborative including more than 90% of California's NICUs. Eligible VLBW infants born between 22 to 29 weeks' gestational age.Varying levels of intensive care.Bronchopulmonary dysplasia was defined as continuous supplemental oxygen use at 36 weeks' postmenstrual age. A combined outcome of BPD or mortality prior to 36 weeks was used. Multivariable logistic regression accounting for hospital as a random effect and gestational age as a risk factor was used to assess individual risk factors for BPD. This model was applied to determine risk-adjusted rates of BPD across hospitals and assess associations between levels of care and BPD rates.The study cohort included 15 779 infants, of which 1534 infants died prior to 36 weeks' postmenstrual age. A total of 7081 infants, or 44.8%, met the primary outcome of BPD or death prior to 36 weeks. Combined BPD or death rates across 116 NICUs varied from 17.7% to 73.4% (interquartile range, 38.7%-54.1%). Compared with level IV NICUs, the risk for developing BPD was higher for level II NICUs (odds ratio, 1.23; 95% CI, 1.02-1.49) and similar for level III NICUs (odds ratio, 1.04; 95% CI, 0.95-1.14).Bronchopulmonary dysplasia or death prior to 36 weeks' postmenstrual age affects approximately 45% of VLBW infants across California. The wide variability in BPD occurrence across hospitals could offer insights into potential risk or preventive factors. Additionally, our findings suggest that increased regionalization of NICU care may reduce BPD among VLBW infants.
View details for DOI 10.1001/jamapediatrics.2014.3676
View details for PubMedID 25642906
We sought to examine the association between increased first-trimester fetal nuchal translucency (NT) measurement and major noncardiac structural birth defects in euploid infants.Included were 75,899 singleton infants without aneuploidy or critical congenital heart defects born in California in 2009 through 2010 with NT measured between 11-14 weeks of gestation. Logistic binomial regression was employed to estimate relative risks (RRs) and 95% confidence intervals (CIs) for occurrence of birth defects in infants with an increased NT measurement (by percentile at crown-rump length [CRL] and by ≥3.5 mm compared to those with measurements <90th percentile for CRL).When considered by CRL adjusted percentile and by measurement ≥3.5 mm, infants with a NT ≥95th percentile were at risk of having ≥1 major structural birth defects (any defect, RR, 1.6; 95% CI, 1.3-1.9; multiple defects, RR, 2.1; 95% CI, 1.3-3.4). Infants with a NT measurement ≥95th percentile were at particularly high risk for pulmonary, gastrointestinal, genitourinary, and musculoskeletal anomalies (RR, 1.6-2.7; 95% CI, 1.1-5.4).Our findings demonstrate that risks of major pulmonary, gastrointestinal, genitourinary, and musculoskeletal structural birth defects exist for NT measurements ≥95th percentile. The ≥3-fold risks were observed for congenital hydrocephalus; agenesis, hypoplasia, and dysplasia of the lung; atresia and stenosis of the small intestine; osteodystrophies; and diaphragm anomalies.
View details for DOI 10.1016/j.ajog.2014.06.025
View details for Web of Science ID 000346585300030
View details for PubMedID 24949541
Pesticide exposures are ubiquitous and of substantial public concern. We examined the potential association of congenital heart defects with residential proximity to commercial agricultural pesticide applications in the San Joaquin Valley, California.Study subjects included 569 heart defect cases and 785 non-malformed controls born from 1997 to 2006 whose mothers participated in a population-based case-control study. Associations with any versus no exposure to physicochemical groups of pesticides and specific chemicals were assessed using logistic regression adjusted for relevant covariates, for 8 heart defect phenotypes that included ≥50 cases and pesticide exposures with ≥5 exposed cases and controls, which resulted in 235 comparisons.38% of cases and controls were classified as exposed to pesticides within a 500m radius of mother׳s address during a 3-month periconceptional window. Adjusted odds ratios (AORs) with 95% CIs excluding 1.0 were observed for 18 comparisons; all were >1 and ranged from 1.9 to 7.1. They included tetralogy of Fallot (n=101 cases) and neonicotinoids; hypoplastic left heart syndrome (n=59) and strobins; coarctation of the aorta (n=74) and pyridazinones; pulmonary valve stenosis (n=53) and bipyridyliums and organophosphates; ventricular septal defects (n=93) and avermectins and pyrethroids; and atrial septal defects (n=132) and dichlorphenoxy acid or esters, organophosphates, organotins, and pyrethroids. No AORs met both of these criteria for d-transposition of the great arteries (n=58) or heterotaxia (n=53).Most pesticides were not associated with increased risk of specific heart defect phenotypes. For the few that were associated, results should be interpreted with caution until replicated in other study populations.
View details for DOI 10.1016/j.envres.2014.08.030
View details for PubMedID 25262086
Gastroschisis is unique because of its substantial risk in pregnancies of adolescent women. Adolescents may have poor diet quality, which places them at higher risk of gastroschisis.We investigated whether better maternal diet quality, measured by 2 different indices, reduced the risk of gastroschisis.We used case-control data from the National Birth Defects Prevention Study to investigate maternal diet quality among 1125 gastroschisis cases and 9483 controls (estimated delivery dates between 1997 and 2009). Cases were ascertained from 10 U.S. birth defect surveillance systems. Control subjects were randomly selected from birth certificates or hospital records. Using a 58-item food-frequency questionnaire, interviewers queried mothers about their average food and cereal intake during the year before conception. Diet quality scores [Diet Quality Index (DQI) and Mediterranean diet score (MDS)] were calculated using specific components. Women were excluded if they consumed <500 or >5000 kcal/d, reported pregestational diabetes, or had >1 missing food item. Quartile-specific adjusted ORs (aORs) were calculated, using as reference the lowest quartile.Overall, we observed a statistically significant decrease with increasing diet quality for both the DQI and MDS. When stratified by maternal race/ethnicity, this finding was confined to Hispanic women. Among Hispanic women, the risk of gastroschisis decreased significantly with increasing DQI quartiles: quartile 2, aOR = 0.58 (95% CI: 0.40, 0.86); quartile 3, aOR = 0.52 (95% CI: 0.36, 0.79); and quartile 4, aOR = 0.48 (95% CI: 0.32, 0.76). Increasing diet quality, as measured by the MDS, showed reduced risk of gastroschisis among women, mostly Hispanic, who were born outside the United States: quartile 2, aOR = 0.62 (95% CI: 0.33, 1.16); quartile 3, aOR = 0.51 (95% CI: 0.28, 0.94); and quartile 4, aOR = 0.50 (95% CI: 0.28, 0.90).Increasing diet quality was associated with a reduced risk of gastroschisis only among Hispanic and foreign-born women, but these findings require replication.
View details for DOI 10.3945/jn.114.201376
View details for Web of Science ID 000343681400016
View details for PubMedID 25332477
It has been observed in several studies that infants with anotia/microtia are more common among Hispanics compared with other racial/ethnic groups. We examined the association between selected Hispanic ethnicity and acculturation factors and anotia/microtia in the National Birth Defects Prevention Study.We examined data from mothers of 351 infants with isolated anotia/microtia and 8435 unaffected infants from the National Birth Defects Prevention Study with an expected delivery date from 1997 to 2007. Sociodemographic, maternal, and acculturation factors (e.g., age, maternal education, household income, body mass index, gestational diabetes, folic acid, smoking, alcohol intake, study center, parental birthplace, and years lived in the United States, maternal language) were assessed as overall risk factors and also as risk factors among subgroups of Hispanics (United States- and foreign-born) versus non-Hispanic whites.Compared with non-Hispanic whites, both United States- and foreign-born Hispanic mothers demonstrated substantially higher odds of delivering infants with anotia/microtia across nearly all strata of sociodemographic and other maternal factors (adjusted odds ratios range: 2.1-11.9). The odds of anotia/microtia was particularly elevated among Hispanic mothers who emigrated from Mexico after age five (adjusted odds ratios = 4.88; 95% confidence interval = 2.93-8.11) or who conducted the interview in Spanish (adjusted odds ratios = 4.97; 95% confidence interval = 3.00-8.24).We observed that certain sociodemographic and acculturation factors are associated with higher risks of anotia/microtia among offspring of Hispanic mothers.
View details for DOI 10.1002/bdra.23282
View details for Web of Science ID 000345690600007
View details for PubMedID 25074828
Preterm birth is an important marker of health and has a prevalence of 12-13% in the U.S. Polycyclic aromatic hydrocarbons (PAHs) are a group of organic contaminants that form during the incomplete combustion of hydrocarbons, such as coal, diesel and gasoline. Studies suggest that exposure to PAHs during pregnancy is related to adverse birth outcomes. The aim of this study is to evaluate the association between exposure to PAHs during the pregnancy and preterm birth.The study population included births from years 2001 to 2006 of women whose maternal residence was within 20km of the primary monitoring site in Fresno, California. Data in the Fresno area were used to form a spatio-temporal model to assign daily exposure to PAHs with 4, 5, or 6 rings at the maternal residence throughout pregnancy of all of the births in the study area. Gestational age at birth and relevant covariates were extracted from the birth certificate.We found an association between PAHs during the last 6 weeks of pregnancy and birth at 20-27 weeks (OR=2.74; 95% CI: 2.24-3.34) comparing the highest quartile to the lower three. The association was consistent when each quartile was compared to the lowest (OR2nd=1.49, 95% CI: 1.08-2.06; OR3rd=2.63, 95% CI:1.93-3.59; OR4th=3.94, 95% CI:3.03-5.12). Inverse associations were also observed for exposure to PAHs during the entire pregnancy and the first trimester and birth at 28-31 weeks and 20-27 weeks.An association between PAH exposure during the 6 weeks before delivery and early preterm birth was observed. However, the inverse association with early preterm birth offers an unclear, and potentially complex, inference of these associations.
View details for DOI 10.1016/j.envres.2014.09.014
View details for Web of Science ID 000346622800031
View details for PubMedID 25282280
Adverse associations between maternal pesticide exposure and neural tube defects (NTDs) have been suggested but not consistently observed. This study used data from the multisite National Birth Defects Prevention Study to examine associations between maternal periconceptional (1 month preconception through 2 months postconception) occupational pesticide exposure and NTDs.Mothers of 502 NTD cases and 2950 unaffected live-born control infants with estimated delivery dates from 1997 through 2002 were included. Duration, categorical intensity scores, and categorical frequency scores for pesticide classes (e.g., insecticides) were assigned using a modified, literature-based job-exposure matrix and maternal-reported occupational histories. Adjusted odds ratios (aORs) and 95% confidence intervals were estimated based on fitted multivariable logistic regression models that described associations between maternal periconceptional occupational pesticide exposure and NTDs. The aORs were estimated for pesticide exposure (any [yes/no] and cumulative exposure [intensity × frequency × duration] to any pesticide class, each pesticide class, or combination of pesticide classes) and all NTD cases combined and NTD subtypes.Positive, but marginally significant or nonsignificant, aORs were observed for exposure to insecticides + herbicides for all NTD cases combined and for spina bifida alone. Similarly, positive aORs were observed for any exposure and cumulative exposure to insecticides + herbicides + fungicides and anencephaly alone and encephalocele alone. All other aORs were near unity.Pesticide exposure associations varied by NTD subtype and pesticide class. Several aORs were increased, but not significantly. Future work should continue to examine associations between pesticide classes and NTD subtypes using a detailed occupational pesticide exposure assessment and examine pesticide exposures outside the workplace.
View details for DOI 10.1002/bdra.23293
View details for Web of Science ID 000345690600009
View details for PubMedID 25124525
The objective of the study was to determine whether pregnancies resulting in early preterm birth (PTB) (<30 weeks) were more likely than term pregnancies to have elevated midtrimester serum tumor necrosis factor alpha (TNF-α) levels combined with lipid patterns suggestive of hyperlipidemia.In 2 nested case-control samples drawn from California and Iowa cohorts, we examined the frequency of elevated midpregnancy serum TNF-α levels (in the fourth quartile [4Q]) and lipid patterns suggestive of hyperlipidemia (eg, total cholesterol, low-density-lipoproteins, or triglycerides in the 4Q, high-density lipoproteins in the first quartile) (considered independently and by co-occurrence) in pregnancies resulting in early PTB compared with those resulting in term birth (n = 108 in California and n = 734 in Iowa). Odds ratios (ORs) and 95% confidence intervals (CIs) estimated in logistic regression models were used for comparisons.Early preterm pregnancies were 2-4 times more likely than term pregnancies to have a TNF-α level in the 4Q co-occurring with indicators of hyperlipidemia (37.5% vs 13.9% in the California sample (adjusted OR, 4.0; 95% CI, 1.1-16.3) and 26.3% vs 14.9% in the Iowa sample (adjusted OR, 2.7; 95% CI, 1.1-6.3). No differences between early preterm and term pregnancies were observed when TNF-α or target lipid abnormalities occurred in isolation. Observed differences were not explicable to any maternal or infant characteristics.Pregnancies resulting in early PTB were more likely than term pregnancies to have elevated midpregnancy TNF-α levels in combination with lipid patterns suggestive of hyperlipidemia.
View details for DOI 10.1016/j.ajog.2014.02.019
View details for PubMedID 24831886
While some of the highest maternal exposures to polycyclic aromatic hydrocarbons (PAHs) occur in the workplace, there is only one previous study of occupational PAH exposure and adverse pregnancy outcomes. We sought to extend this literature using interview data combined with detailed exposure assessment.Data for 1997-2002 were analysed from mothers of infants without major birth defects in the National Birth Defects Prevention Study, a large population-based case-control study in the USA. Maternal telephone interviews yielded information on jobs held in the month before conception through delivery. From 6252 eligible control mothers, 2803 completed the interview, had a job, met other selection criteria, and were included in the analysis. Two industrial hygienists independently assessed occupational exposure to PAHs from the interview and reviewed results with a third to reach consensus. Small for gestational age (SGA) was the only adverse pregnancy outcome with enough exposed cases to yield meaningful results. Logistic regression estimated crude and adjusted ORs.Of the 2803 mothers, 221 (7.9%) had infants who were SGA. Occupational PAH exposure was found for 17 (7.7%) of the mothers with SGA offspring and 102 (4.0%) of the remaining mothers. Almost half the jobs with exposure were related to food preparation and serving. After adjustment for maternal age, there was a significant association of occupational exposure with SGA (OR=2.2, 95% CI 1.3 to 3.8).Maternal occupational exposure to PAHs was found to be associated with increased risk of SGA offspring.
View details for DOI 10.1136/oemed-2013-101833
View details for PubMedID 24893704
Epidemiologic literature suggests that exposure to air pollutants is associated with fetal development.We investigated maternal exposures to air pollutants during weeks 2-8 of pregnancy and their associations with congenital heart defects.Mothers from the National Birth Defects Prevention Study, a nine-state case-control study, were assigned 1-week and 7-week averages of daily maximum concentrations of carbon monoxide, nitrogen dioxide, ozone, and sulfur dioxide and 24-hr measurements of fine and coarse particulate matter using the closest air monitor within 50 km to their residence during early pregnancy. Depending on the pollutant, a maximum of 4,632 live-birth controls and 3,328 live-birth, fetal-death, or electively terminated cases had exposure data. Hierarchical regression models, adjusted for maternal demographics and tobacco and alcohol use, were constructed. Principal component analysis was used to assess these relationships in a multipollutant context.Positive associations were observed between exposure to nitrogen dioxide and coarctation of the aorta and pulmonary valve stenosis. Exposure to fine particulate matter was positively associated with hypoplastic left heart syndrome but inversely associated with atrial septal defects. Examining individual exposure-weeks suggested associations between pollutants and defects that were not observed using the 7-week average. Associations between left ventricular outflow tract obstructions and nitrogen dioxide and between hypoplastic left heart syndrome and particulate matter were supported by findings from the multipollutant analyses, although estimates were attenuated at the highest exposure levels.Using daily maximum pollutant levels and exploring individual exposure-weeks revealed some positive associations between certain pollutants and defects and suggested potential windows of susceptibility during pregnancy.
View details for DOI 10.1289/ehp.1307289
View details for Web of Science ID 000341713800024
View details for PubMedID 24727555
The objective of the study was to examine the association between placental abruption, maternal characteristics, and routine first- and second-trimester aneuploidy screening analytes.The study consisted of an analysis of 1017 women with and 136,898 women without placental abruption who had first- and second-trimester prenatal screening results, linked birth certificate, and hospital discharge records for a live-born singleton. Maternal characteristics and first- and second-trimester aneuploidy screening analytes were analyzed using logistic binomial regression.Placental abruption was more frequent among women of Asian race, age older than 34 years, women with chronic and pregnancy-associated hypertension, preeclampsia, preexisting diabetes, previous preterm birth, and interpregnancy interval less than 6 months. First-trimester pregnancy-associated plasma protein-A of the fifth percentile or less, second-trimester alpha fetoprotein of the 95th percentile or greater, unconjugated estriol of the fifth percentile or less, and dimeric inhibin-A of the 95th percentile or greater were associated with placental abruption as well. When logistic models were stratified by the presence or absence of hypertensive disease, only maternal age older than 34 years (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0-2.0), pregnancy-associated plasma protein-A of the 95th percentile or less (OR, 1.9; 95% CI, 1.2-3.1), and alpha fetoprotein of the 95th percentile or greater (OR, 2.3; 95% CI, 1.4-3.8) remained statistically significantly associated for abruption.In this large, population-based cohort study, abnormal maternal aneuploidy serum analyte levels were associated with placental abruption, regardless of the presence of hypertensive disease.
View details for DOI 10.1016/j.ajog.2014.03.027
View details for PubMedID 24631707
Findings from studies examining risk of preterm birth associated with elevated prepregnancy body mass index (BMI) have been inconsistent.Within a large population-based cohort, we explored associations between prepregnancy BMI and spontaneous preterm birth across a spectrum of BMI, gestational age, and racial/ethnic categories. We analysed data for 989 687 singleton births in California, 2007-09. Preterm birth was grouped as 20-23, 24-27, 28-31, or 32-36 weeks gestation (compared with 37-41 weeks). BMI was categorised as <18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0-34.9 (obese I); 35.0-39.9 (obese II); and ≥40.0 (obese III). We assessed associations between BMI and spontaneous preterm birth of varying severity among non-Hispanic White, Hispanic, and non-Hispanic Black women.Analyses of mothers without hypertension and diabetes, adjusted for age, education, height, and prenatal care initiation, showed obesity categories I-III to be associated with increased risk of spontaneous preterm birth at 20-23 and 24-27 weeks among those of parity 1 in each race/ethnic group. Relative risks for obese III and preterm birth at 20-23 weeks were 6.29 [95% confidence interval (CI) 3.06, 12.9], 4.34 [95% CI 2.30, 8.16], and 4.45 [95% CI 2.53, 7.82] for non-Hispanic Whites, non-Hispanic Blacks, and Hispanics, respectively. A similar, but lower risk, pattern was observed for women of parity ≥2 and preterm birth at 20-23 weeks. Underweight was associated with modest risks for preterm birth at ≥24 weeks among women in each racial/ethnic group regardless of parity.The association between women's prepregnancy BMI and risk of spontaneous preterm birth is complex and is influenced by race/ethnicity, gestational age, and parity.
View details for DOI 10.1111/ppe.12125
View details for Web of Science ID 000337614300005
Congenital heart defects are the most common malformation, and are the foremost causes of mortality in the first year of life. Among congenital heart defects, conotruncal defects represent about 20% and are severe malformations with significant morbidity. Insulin gene enhancer protein 1 (ISL1) has been considered a candidate gene for conotruncal heart defects based on its embryonic expression pattern and heart defects induced in Isl1 knockout mice. Nevertheless no mutation of ISL1 has been reported from any human subject with a heart defect. From a population base of 974,579 births during 1999-2004, we used multiplex ligation-dependent probe amplification to screen for microdeletions/duplications of ISL1 among 389 infants with tetralogy of Fallot or d-transposition of the great arteries (d-TGA). We also sequenced all exons of ISL1. We identified a novel 20-kb microdeletion encompassing the entire coding region of ISL1, but not including either flanking gene, from an infant with d-TGA. We confirmed that the deletion was caused by nonhomologous end joining mechanism. Sequencing of exons of ISL1 did not reveal any subject with a novel nonsynonymous mutation. This is the first report of an ISL1 mutation of a child with a congenital heart defect.
View details for DOI 10.1002/mgg3.75
View details for PubMedID 25077177
We examined the association of maternal stressful life events and social support with risks of birth defects using National Birth Defects Prevention Study data, a population-based case-control study.We examined seven stressful life events and three social support questions applicable to the periconceptional period, among mothers of 552 cases with neural tube defects (NTDs), 413 cleft palate (CP), 797 cleft lip ± cleft palate (CLP), 189 d-transposition of the great arteries (dTGA), 311 tetralogy of Fallot (TOF), and 2974 non-malformed controls. A stressful life events index equalled the sum of 'yes' responses to the seven questions. Social support questions were also summed to form an index. Data were analyzed using logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), adjusted for maternal race-ethnicity, age, education, body mass index, smoking, drinking, and intake of vitamin supplements.Associations with the stress index tended to be higher with higher scores, but few 95% CIs excluded one. A four-point increase in the index was moderately associated with NTDs (OR 1.5, [95% CI 1.1, 2.0]) and CLP (OR 1.3, [95% CI 1.0, 1.7]). The social support index tended to be associated with reduced risk but most 95% CIs included one, with the exception of dTGA (OR for a score of 3 vs 0 was 0.5 [95% CI 0.3, 0.8]).Maternal periconceptional stressful life events, social support, and the two factors in combination were at most modestly, if at all, associated with risks of the studied birth defects.
View details for DOI 10.1111/ppe.12123
View details for Web of Science ID 000337614300009
View details for PubMedID 24697924
Maternal obesity is a major source of preventable perinatal morbidity, but studies of the relationship between obesity and preterm birth have been inconsistent. This review looks at two major studies covering just under 3.5 million births, from California, USA, and Sweden.Inconsistent findings in previous studies appear to stem from the complex relationship between obesity and preterm birth. Initiatives to decrease maternal obesity represent an important strategy in reducing preterm birth.
View details for DOI 10.1111/apa.12616
View details for Web of Science ID 000335754700012
View details for PubMedID 24575829
Identification of maternal environmental factors influencing preterm birth risks is important to understand the reasons for the increase in prematurity since 1990. Here, we utilized a health survey, the US National Health and Nutrition Examination Survey (NHANES) to search for personal environmental factors associated with preterm birth. 201 urine and blood markers of environmental factors, such as allergens, pollutants, and nutrients were assayed in mothers (range of N: 49-724) who answered questions about any children born preterm (delivery <37 weeks). We screened each of the 201 factors for association with any child born preterm adjusting by age, race/ethnicity, education, and household income. We attempted to verify the top finding, urinary bisphenol A, in an independent study of pregnant women attending Lucile Packard Children's Hospital. We conclude that the association between maternal urinary levels of bisphenol A and preterm birth should be evaluated in a larger epidemiological investigation.
View details for DOI 10.1016/j.reprotox.2013.12.005
View details for Web of Science ID 000336415800001
IMPORTANCE Critical congenital heart disease (CCHD) was added to the Recommended Uniform Screening Panel for Newborns in the United States in 2011. Many states have recently adopted or are considering requirements for universal CCHD screening through pulse oximetry in birth hospitals. Limited previous research is directly applicable to the question of how many US infants with CCHD might be identified through screening. OBJECTIVES To estimate the proportion of US infants with late detection of CCHD (>3 days after birth) based on existing clinical practice and to investigate factors associated with late detection. DESIGN, SETTING, AND PARTICIPANTS Descriptive and multivariable analysis. Data were obtained from a multisite population-based study of birth defects in the United States, the National Birth Defects Prevention Study (NBDPS). We included all live-born infants with estimated dates of delivery from January 1, 1998, through December 31, 2007, and nonsyndromic, clinically verified CCHD conditions potentially detectable through screening via pulse oximetry. MAIN OUTCOMES AND MEASURES The main outcome measure was the proportion of infants with late detection of CCHD through echocardiography or at autopsy under the assumption that universal screening at birth hospitals might reduce the number of such late diagnoses. Secondary outcome measures included prevalence ratios for associations between selected demographic and clinical factors and late detection of CCHD. RESULTS Of 3746 live-born infants with nonsyndromic CCHD, late detection occurred in 1106 (29.5% [95% CI, 28.1%-31.0%]), including 6 (0.2%) (0.1%-0.4%) first receiving a diagnosis at autopsy more than 3 days after birth. Late detection varied by CCHD type from 9 of 120 infants (7.5% [95% CI, 3.5%-13.8%]) with pulmonary atresia to 497 of 801 (62.0% [58.7%-65.4%]) with coarctation of the aorta. In multivariable analysis, late detection varied significantly by CCHD type and study site, and infants with extracardiac defects were significantly less likely to have late detection of CCHD (adjusted prevalence ratio, 0.58 [95% CI, 0.49-0.69]). CONCLUSIONS AND RELEVANCE We estimate that 29.5% of live-born infants with nonsyndromic CCHD in the NBDPS received a diagnosis more than 3 days after birth and therefore might have benefited from routine CCHD screening at birth hospitals. The number of infants in whom CCHD was detected through screening likely varies by several factors, including CCHD type. Additional population-based studies of screening in practice are needed.
View details for DOI 10.1001/jamapediatrics.2013.4779
View details for Web of Science ID 000336839200013
Birth defects are a leading cause of infant morbidity and mortality worldwide. The vast majority of birth defects are nonsyndromic, and although their etiologies remain mostly unknown, evidence supports the hypothesis that they result from the complex interaction of genetic, epigenetic, environmental, and lifestyle factors. Since our last review published in 2002 describing the basic tools of genetic epidemiology used to study nonsyndromic structural birth defects, many new approaches have become available and have been used with varying success. Through rapid advances in genomic technologies, investigators are now able to investigate large portions of the genome at a fraction of previous costs. With next-generation sequencing, research has progressed from assessing a small percentage of single-nucleotide polymorphisms to assessing the entire human protein-coding repertoire (exome)-an approach that is starting to uncover rare but informative mutations associated with nonsyndromic birth defects. Herein, we report on the current state of the genetic epidemiology of birth defects and comment on future challenges and opportunities. We consider issues of study design, and we discuss common variant approaches, including candidate gene studies and genome-wide association studies. We also discuss the complexities embedded in exploring interactions between genes and the environment. We complete our review by describing new and promising next-generation sequencing technologies and examining how the study of epigenetic mechanisms could become the key to unraveling the complex etiologies of nonsyndromic structural birth defects.
View details for DOI 10.1001/jamapediatrics.2013.4858
View details for Web of Science ID 000336839200014
View details for PubMedID 24515445
The purpose of this study was to evaluate whether maternal febrile illnesses in early pregnancy are associated with increased risk for congenital heart defects in the offspring and whether such risk is mitigated by multivitamin supplement use.From a multistate population-based case-control study (National Birth Defects Prevention Study), we compared maternal reports of first-trimester febrile illness from 7020 subjects with heart defects and 6746 unaffected control subjects who were born from 1997 through 2005. Relative risks were computed with no fever or infection during the first trimester as reference group and were adjusted for potential confounders.First-trimester febrile illness was reported by 7.4% of control mothers (1 in 13). Febrile genitourinary infections were associated with selected heart defects, particularly right-sided obstructive defects (odds ratios, >3) and possibly others, whereas common respiratory illnesses were associated with low-to-negligible risks for most heart defects. When risk estimates were elevated, they tended to be mitigated when multivitamin supplements had been taken in the periconceptional period.The source of fever and the use of supplements appear to influence the risk for heart defects. This information can be helpful in counseling and research, in particular with regard to primary prevention.
View details for DOI 10.1016/j.ajog.2013.10.880
View details for Web of Science ID 000333401900023
View details for PubMedID 24184180
We examined whether early gestational exposures to pesticides were associated with an increased risk of anencephaly, spina bifida, cleft lip with or without cleft palate (CLP), or cleft palate only. We used population-based data along with detailed information from maternal interviews. Exposure estimates were based on residential proximity to agricultural pesticide applications during early pregnancy. The study population derived from the San Joaquin Valley, California (1997-2006). Analyses included 73 cases with anencephaly, 123 with spina bifida, 277 with CLP, and 117 with cleft palate only in addition to 785 controls. A total of 38% of the subjects were exposed to 52 chemical groups and 257 specific chemicals. There were relatively few elevated odds ratios with 95% confidence intervals that excluded 1 after adjustment for relevant covariates. Those chemical groups included petroleum derivatives for anencephaly, hydroxybenzonitrile herbicides for spina bifida, and 2,6-dinitroaniline herbicides and dithiocarbamates-methyl isothiocyanate for CLP. The specific chemicals included 2,4-D dimethylamine salt, methomyl, imidacloprid, and α-(para-nonylphenyl)-ω-hydroxypoly(oxyethylene) phosphate ester for anencephaly; the herbicide bromoxynil octanoate for spina bifida; and trifluralin and maneb for CLP. Adjusted odds ratios ranged from 1.6 to 5.1. Given that such odds ratios might have arisen by chance because of the number of comparisons, our study showed a general lack of association between a range of agricultural pesticide exposures and risks of selected birth defects.
View details for DOI 10.1093/aje/kwt324
View details for Web of Science ID 000333246800011
View details for PubMedID 24553680
Spina bifida is one of the most common neural tube defects (NTDs) with a complex etiology. Variants in planar cell polarity (PCP) genes have been associated with NTDs including spina bifida in both animal models and human cohorts. In this study, we sequenced all exons of CELSR1 in 192 spina bifida patients from a California population to determine the contribution of CELSR1 mutations in the studied population. Novel and rare variants identified in these patients were subsequently genotyped in 190 ethnically matched control individuals. Six missense mutations not found in controls were predicted to be deleterious by both SIFT and PolyPhen. Two TG dinucleotide repeat variants were individually detected in 2 spina bifida patients but not detected in controls. In vitro functional analysis showed that the two TG dinucleotide repeat variants not only changed subcellular localization of the CELSR1 protein, but also impaired the physical association between CELSR1 and VANGL2, and thus diminished the ability to recruit VANGL2 for cell-cell contact. In total, 3% of our spina bifida patients carry deleterious or predicted to be deleterious CELSR1 mutations. Our findings suggest that CELSR1 mutations contribute to the risk of spina bifida in a cohort of spina bifida patients from California.
View details for DOI 10.1371/journal.pone.0092207
View details for Web of Science ID 000332858400150
View details for PubMedID 24632739
Congenital heart defects (CHDs) are common malformations, affecting four to eight per 1,000 total births. Conotruncal defects are an important pathogenetic subset of CHDs, comprising nearly 20% of the total. Although both environmental and genetic factors are known to contribute to the occurrence of conotruncal defects, the causes remain unknown for most. To identify novel candidate genes/loci, we used array comparative genomic hybridization to detect chromosomal microdeletions/duplications. From a population base of 974,579 total births born during 1999-2004, we screened 389 California infants born with tetralogy of Fallot or d-transposition of the great arteries. We found that 1.7% (5/288) of males with a conotruncal defect had sex chromosome aneuploidy, a sevenfold increased frequency (relative risk = 7.0; 95% confidence interval 2.9-16.9). We identified eight chromosomal microdeletions/duplications for conotruncal defects. From these duplications and deletions, we found five high priority candidate genes (GATA4, CRKL, BMPR1A, SNAI2, and ZFHX4). This is the initial report that sex chromosome aneuploidy is associated with conotruncal defects among boys. These chromosomal microduplications/deletions provide evidence that GATA4, SNAI2, and CRKL are highly dosage sensitive genes involved in outflow tract development. Genome wide screening for copy number variation can be productive for identifying novel genes/loci contributing to non-syndromic common malformations.
View details for DOI 10.1002/ajmg.a.36291
View details for PubMedID 24127225
Evidence exists for an association between use of vitamin supplements with folic acid in early pregnancy and reduced risk for offspring with conotruncal heart defects. A few observations have been made about nutrients related to one-carbon metabolism other than folate. Our prospective study attempted to extend information on nutrition and conotruncal heart defects by measuring analytes in mid-pregnancy sera.This study included data from a repository of women's mid-pregnancy serum specimens based on screened pregnancies in California from 2002-2007. Each woman's specimen was linked with delivery information to determine whether her fetus had a conotruncal heart defect or another structural malformation, or was nonmalformed. We identified 140 conotruncal cases and randomly selected 280 specimens as nonmalformed controls. Specimens were tested for a variety of analytes, including homocysteine, methylmalonic acid, folate, vitamin B12 , pyridoxal phosphate, pyridoxal, pyridoxic acid, riboflavin, total choline, betaine, methionine, cysteine, cystathionine, arginine, asymmetric and symmetric dimethylarginine.We did not observe statistical evidence for substantial differences between cases and controls for any of the measured analytes. Analyses specifically targeting B-vitamins also did not reveal differences between cases and controls. Birth Defects Research (Part A) 100:107-115, 2014. © 2014 Wiley Periodicals, Inc.
View details for DOI 10.1002/bdra.23224
View details for Web of Science ID 000331616400006
View details for PubMedID 24532477
Single-gene analyses indicate that maternal genes associated with metabolic conditions (e.g., obesity) may influence the risk of neural tube defects (NTDs). However, to our knowledge, there have been no assessments of maternal-fetal metabolic gene-gene interactions and NTDs. We investigated 23 single nucleotide polymorphisms among 7 maternal metabolic genes (ADRB3, ENPP1, FTO, LEP, PPARG, PPARGC1A, and TCF7L2) and 2 fetal metabolic genes (SLC2A2 and UCP2). Samples were obtained from 737 NTD case-parent triads included in the National Birth Defects Prevention Study for birth years 1999-2007. We used a 2-step approach to evaluate maternal-fetal gene-gene interactions. First, a case-only approach was applied to screen all potential maternal and fetal interactions (n = 76), as this design provides greater power in the assessment of gene-gene interactions compared to other approaches. Specifically, ordinal logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) for each maternal-fetal gene-gene interaction, assuming a log-additive model of inheritance. Due to the number of comparisons, we calculated a corrected p-value (q-value) using the false discovery rate. Second, we confirmed all statistically significant interactions (q < 0.05) using a log-linear approach among case-parent triads. In step 1, there were 5 maternal-fetal gene-gene interactions with q < 0.05. The "top hit" was an interaction between maternal ENPP1 rs1044498 and fetal SLC2A2 rs6785233 (interaction OR = 3.65, 95% CI: 2.32-5.74, p = 2.09×10(-8), q=0.001), which was confirmed in step 2 (p = 0.00004). Our findings suggest that maternal metabolic genes associated with hyperglycemia and insulin resistance and fetal metabolic genes involved in glucose homeostasis may interact to increase the risk of NTDs.
View details for DOI 10.1016/j.ymgme.2013.11.004
View details for Web of Science ID 000330158100007
View details for PubMedID 24332798
We examined whether variants in genes related to sex hormone biosynthesis and metabolism were associated with hypospadias in humans. We examined 332 relatively common tag single-nucleotide polymorphisms (tagSNPs) in 20 genes. Analyses included 633 cases (84 mild, 322 moderate, 212 severe and 15 undetermined severity) and 855 population-based non-malformed male controls born in California from 1990 to 2003. We used logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (CI) for each SNP. Several of the 332 studied SNPs had p < 0.01: one in CYP3A4, four in HSD17B3, one in HSD3B1, two in STARD3, 10 in SRD5A2 and seven in STS. In addition, haplotype analyses gave several associations with p < 0.01. For HSD17B3, 14-SNP and 5-SNP blocks had ORs of 1.5 (95% CI 1.1, 2.0, p < 0.001) and 2.8 (95% CI 1.6, 4.8, p < 0.001) respectively. For SRD5A2, 9-SNP, 3-SNP and 8-SNP blocks had ORs of 1.7 (95% CI 1.3, 2.2, p < 0.001), 1.4 (95% CI 1.1, 1.8, p = 0.008) and 1.5 (95% CI 1.2, 1.9, p = 0.002) respectively. Our study indicates that several genes that contribute to sex hormone biosynthesis and metabolism are associated with hypospadias risk.
View details for DOI 10.1111/j.2047-2927.2013.00165.x
View details for Web of Science ID 000328729900019
View details for PubMedID 24281767
Human preterm birth (PTB) is a complex medical outcome influenced by a combination of genetic and environmental factors. Research on the causative factors of PTB has mostly focused on demographic, socio-behavioral and environmental risk factors. Recent studies turn the spotlight on the effects of heavy metals exposure on adverse pregnancy outcomes. Here we present and evaluate the hypothesis that heavy metals may cause PTB through oxidative stress, and that this effect may be modified by polymorphisms in genes related to oxidative stress. Indeed, accumulating data suggest that the risk of PTB is correlated with polymorphisms in genes involved in detoxification, oxidative stress and lipid metabolism. These and other polymorphisms have independently been associated with susceptibility to the adverse effects of heavy metals.
View details for DOI 10.1016/j.reprotox.2013.06.072
View details for Web of Science ID 000327569100003
View details for PubMedID 23811355
PURPOSE: We determined whether variants in genes associated with genital tubercle (the anlage for the penis) and early urethral development were associated with hypospadias in humans. MATERIALS AND METHODS: We examined 293 relatively common tagSNPs in BMP4, BMP7, FGF8, FGF10, FGFR2, HOXA13, HOXD13, HOXA4, HOXB6, SRY, WT1, WTAP, SHH, GLI1, GLI2, and GLI3. The analysis included 624 cases (81 mild, 319 moderate, 209 severe, 15 undetermined severity) and 844 population-based non-malformed male controls born in California from 1990-2003. RESULTS: There were 28 SNPs for which any of the comparisons (i.e., overall or for a specific severity) had a p-value <0.01. The homozygous variant genotypes for four SNPs in BMP7were associated with at least 2-fold increased risk of hypospadias, regardless of severity. Five SNPs for FGF10were associated with 3- to 4-fold increased risks, regardless of severity; for four of them, results were restricted to whites. For GLI1, GLI2and GLI3, there were 12 associated SNPs but results were inconsistent by severity and race-ethnicity. For SHH, one SNP was associated with 2.4-fold increased risk of moderate hypospadias. For WT1, six SNPs were associated with approximately 2-fold increased risks, primarily for severe hypospadias. CONCLUSIONS: This study provides evidence that SNPs in several genes that contribute to genital tubercle and early urethral development are associated with hypospadias risk.
View details for DOI 10.1016/j.juro.2013.05.061
View details for Web of Science ID 000325471400089
View details for PubMedID 23727413
Birth defects are a leading cause of infant morbidity and mortality. Studies suggest associations between environmental contaminants and some structural anomalies, although evidence is limited and several anomalies have not been investigated previously.We used data from the California Center of the National Birth Defects Prevention Study and the Children's Health and Air Pollution Study to estimate the odds of 26 congenital birth defect phenotypes with respect to quartiles of seven ambient air pollutant and traffic exposures in California during the first 2 months of pregnancy, 1997 to 2006 (874 cases and 849 controls). We calculated odds ratios (adjusted for maternal race/ethnicity, education, and vitamin use; aOR) for 11 phenotypes that had at least 40 cases.Few odds ratios had confidence intervals that did not include 1.0. Odds of esophageal atresia were increased for the highest versus lowest of traffic density (aOR = 2.8, 95% confidence interval [CI], 1.1-7.4) and PM10 exposure (aOR 4.9; 95% CI, 1.4-17.2). PM10 was associated with a decreased risk of hydrocephaly (aOR= 0.3; 95% CI, 0.1-0.9) and CO with decreased risk of anotia/microtia (aOR = 0.4; 95% CI, 0.2-0.8) and transverse limb deficiency (aOR = 0.4; 95% CI, 0.2-0.9), again reflecting highest versus lowest quartile comparisons.Most analyses showed no substantive association between air pollution and the selected birth defects with few exceptions of mixed results. Birth Defects Research (Part A) 97:730-735, 2013. © 2013 Wiley Periodicals, Inc.
View details for DOI 10.1002/bdra.23175
View details for Web of Science ID 000327219400003
View details for PubMedID 24108522
Background:Evidence indicates that maternal nutrient intake may play a role in the development of birth defects. We investigated the association of maternal periconceptional intake of vitamin supplements and dietary nutrients with risk of developing cleft palate (CP) and cleft lip with or without cleft palate (CLP).Methods:Data were from a population-based, case-control study of fetuses and liveborn infants delivered in California,1999-2003. Analyses included 170 cases with CP, 425 with CLP, and 534 nonmalformed controls. Dietary intake was estimated from a food frequency questionnaire.Results:Vitamin supplement intake was associated with a modestly decreased risk of clefts, but the confidence intervals include one. Among women who did not use vitamin supplements, dietary intake of several micronutrients was associated with risk of clefts. We found at least a two-fold elevated risk of CP with low intake of riboflavin, magnesium, calcium, vitamin B12, and zinc; all CIs excluded 1.0. For CLP, we found at least a two-fold elevated risk with low intake of niacin, riboflavin, vitamin B12, and calcium, and a decreased risk with high intake of folate and cryptoxanthin; all CIs excluded 1.0.Conclusion:Results suggest that periconceptional nutrient intake may be associated with risk of CP and CLP.Pediatric Research (2013); doi:10.1038/pr.2013.115.
View details for DOI 10.1038/pr.2013.115
View details for Web of Science ID 000326060000015
Twin studies suggest that heritability of moderate-severe bronchopulmonary dysplasia (BPD) is 53% to 79%, we conducted a genome-wide association study (GWAS) to identify genetic variants associated with the risk for BPD.The discovery GWAS was completed on 1726 very low birth weight infants (gestational age = 25(0)-29(6/7) weeks) who had a minimum of 3 days of intermittent positive pressure ventilation and were in the hospital at 36 weeks' postmenstrual age. At 36 weeks' postmenstrual age, moderate-severe BPD cases (n = 899) were defined as requiring continuous supplemental oxygen, whereas controls (n = 827) inhaled room air. An additional 795 comparable infants (371 cases, 424 controls) were a replication population. Genomic DNA from case and control newborn screening bloodspots was used for the GWAS. The replication study interrogated single-nucleotide polymorphisms (SNPs) identified in the discovery GWAS and those within the HumanExome beadchip.Genotyping using genomic DNA was successful. We did not identify SNPs associated with BPD at the genome-wide significance level (5 × 10(-8)) and no SNP identified in previous studies reached statistical significance (Bonferroni-corrected P value threshold .0018). Pathway analyses were not informative.We did not identify genomic loci or pathways that account for the previously described heritability for BPD. Potential explanations include causal mutations that are genetic variants and were not assayed or are mapped to many distributed loci, inadequate sample size, race ethnicity of our study population, or case-control differences investigated are not attributable to underlying common genetic variation.
View details for DOI 10.1542/peds.2013-0533
View details for Web of Science ID 000322957300052
Experimental data indicate that gestational exposures to estrogenic compounds impact risk of hypospadias. We examined whether risk of hypospadias (i.e., a congenital malformation in which the opening of the penile urethra occurs on the ventral side of the penis) was associated with maternal intake of phytoestrogens, given their potential impact on estrogen metabolism. The analysis included data on mothers of 1,250 hypospadias cases and 3,118 controls who delivered their infants from 1997 to 2005 and participated in the National Birth Defects Prevention Study, a multistate, population-based, case-control study. After adjustment for several covariates, high intakes of daidzein, genistein, glycetin, secoisolariciresinol, total isoflavones, total lignans, and total phytoestrogens were associated with reduced risks; odds ratios comparing intakes ≥90th percentile with intakes between the 11th and 89th percentiles ranged from 0.6 to 0.8. For example, the odds ratio for total phytoestrogen intake was 0.7 (95% confidence interval: 0.5, 1.0). This study represents the first large-scale analysis of phytoestrogen intake and hypospadias. The observed associations merit investigation in additional populations before firm conclusions can be reached.
View details for DOI 10.1093/aje/kws591
View details for Web of Science ID 000322734500012
View details for PubMedID 23752918
Objective To examine maternal dietary intake and preterm delivery.Study Design Data included 5738 deliveries from the National Birth Defects Prevention Study. Odds ratios (ORs) reflected risks of delivery at <32, 32-34, or 35-36 versus ≥37 weeks for maternal intake in the lowest or highest quartile of nutrient intake compared with the middle two.Results Among deliveries < 32 weeks, many ORs were ≥1.5 or ≤0.7, but few confidence intervals excluded one. ORs were ≥1.5 for lowest quartiles of protein, thiamin, riboflavin, choline, vitamin A, α-carotene, β-carotene, vitamin E, iron, copper, and zinc and for highest quartiles of carbohydrate, glycemic index, and Mediterranean Diet Score. ORs were ≤0.7 for lowest quartiles of glycemic index and betaine and for highest quartiles of protein, alanine, methionine, vitamin B6, betaine, and calcium. Few ORs met these criteria for later preterm deliveries.Conclusions Results suggested an association of nutrient intake with earlier preterm deliveries.
View details for DOI 10.1055/s-0032-1329686
View details for Web of Science ID 000322021900009
View details for PubMedID 23208764
Neural tube defects (NTDs) (OMIM #182940) including anencephaly, spina bifida and craniorachischisis, are severe congenital malformations that affect 0.5-1 in 1,000 live births in the United States, with varying prevalence around the world. Mutations in planar cell polarity (PCP) genes are believed to cause a variety of NTDs in both mice and humans. SCRIB is a PCP-associated gene. Mice that are homozygous for the Scrib p.I285K and circletail (Crc) mutations, present with the most severe form of NTDs, namely craniorachischisis. A recent study reported that mutations in SCRIB were associated with craniorachischisis in humans, but whether SCRIB mutations contribute to increased spina bifida risk is still unknown. We sequenced the SCRIB gene in 192 infants with spina bifida and 190 healthy controls. Among the spina bifida patients, we identified five novel missense mutations that were predicted-to-be-deleterious by the PolyPhen software. Of these five mutations, three of them (p.P1043L, p.P1332L, p.L1520R) significantly affected the subcellular localization of SCRIB. In addition, we demonstrated that the craniorachischisis mouse line-90 mutation I285K, also affected SCRIB subcellular localization. In contrast, only one novel missense mutation (p.A1257T) was detected in control samples, and it was predicted to be benign. This study demonstrated that rare deleterious mutations of SCRIB may contribute to the multifactorial risk for human spina bifida.
View details for DOI 10.1371/journal.pone.0069262
View details for Web of Science ID 000322838900029
View details for PubMedID 23922697
Congenital anomalies are a leading cause of infant morbidity and mortality. Studies suggest associations between environmental contaminants and some anomalies, although evidence is limited.We used data from the California Center of the National Birth Defects Prevention Study and the Children's Health and Air Pollution Study to estimate the odds of 27 congenital heart defects with respect to quartiles of seven ambient air pollutant and traffic exposures in California during the first 2 months of pregnancy, 1997-2006 (n = 822 cases and n = 849 controls).Particulate matter < 10 microns (PM10 ) was associated with pulmonary valve stenosis [adjusted odds ratio (aOR)Fourth Quartile = 2.6] [95% confidence intervals (CI) 1.2, 5.7] and perimembranous ventricular septal defects (aORThird Quartile = 2.1) [95% CI 1.1, 3.9] after adjusting for maternal race/ethnicity, education and multivitamin use. PM2.5 was associated with transposition of the great arteries (aORThird Quartile = 2.6) [95% CI 1.1, 6.5] and inversely associated with perimembranous ventricular septal defects (aORFourth Quartile = 0.5) [95% CI 0.2, 0.9]. Secundum atrial septal defects were inversely associated with carbon monoxide (aORFourth Quartile = 0.4) [95% CI 0.2, 0.8] and PM2.5 (aORFourth Quartile = 0.5) [95% CI 0.3, 0.8]. Traffic density was associated with muscular ventricular septal defects (aORFourth Quartile = 3.0) [95% CI 1.2, 7.8] and perimembranous ventricular septal defects (aORThird Quartile = 2.4) [95% CI 1.3, 4.6], and inversely associated with transposition of the great arteries (aORFourth Quartile = 0.3) [95% CI 0.1, 0.8].PM10 and traffic density may contribute to the occurrence of pulmonary valve stenosis and ventricular septal defects, respectively. The results were mixed for other pollutants and had little consistency with previous studies.
View details for DOI 10.1111/ppe.12055
View details for Web of Science ID 000320474700003
View details for PubMedID 23772934
Congenital hydrocephalus is a condition characterized by accumulation of cerebrospinal fluid in the ventricles of the brain. Prenatal infections are risk factors for some birth defects. This pilot study investigated whether residual dried blood spots (DBS) could be used to assess infections as risk factors for birth defects by examining the associations between prenatal infection with Toxoplasma gondii (T. gondii) or cytomegalovirus (CMV) with congenital hydrocephalus.Case-infants with hydrocephalus (N=410) were identified among live-born infants using birth defects surveillance systems in California, North Carolina, and Texas. Control-infants without birth defects were randomly selected from the same geographic areas and time periods as case-infants (N=448). We tested residual DBS from case- and control-infants for T. gondii immunoglobulin M and CMV DNA. When possible, we calculated crude odds ratios (cORs) and confidence intervals (CIs).Evidence for prenatal T. gondii infection was more common among case-infants (1.2%) than control-infants (0%; p=0.11), and evidence for prenatal CMV infection was higher among case-infants (1.5%) than control-infants (0.7%; cOR: 2.3; 95% CI: 0.48, 13.99).Prenatal infections with T. gondii and CMV occurred more often among infants with congenital hydrocephalus than control-infants, although differences were not statistically significant. This pilot study highlighted some challenges in using DBS to examine associations between certain infections and birth defects, particularly related to reduced sensitivity and specimen storage conditions. Further study with increased numbers of specimens and higher quality specimens should be considered to understand better the contribution of these infections to the occurrence of congenital hydrocephalus.
View details for DOI 10.1002/bdra.23138
View details for Web of Science ID 000326397800001
View details for PubMedID 23716471
The purpose of this study was to examine the relationship between typically measured prenatal screening biomarkers and early-preterm birth in euploid pregnancies.The study included 345 early-preterm cases (<30 weeks of gestation) and 1725 control subjects who were drawn from a population-based sample of California pregnancies who had both first- and second-trimester screening results. Logistic regression analyses were used to compare patterns of biomarkers in cases and control subjects and to develop predictive models. Replicability of the biomarker early-preterm relationships that was revealed by the models was evaluated by examination of the frequency and associated adjusted relative risks (RRs) for early-preterm birth and for preterm birth in general (<37 weeks of gestation) in pregnancies with identified abnormal markers compared with pregnancies without these markers in a subsequent independent California cohort of screened pregnancies (n = 76,588).The final model for early-preterm birth included first-trimester pregnancy-associated plasma protein A in the ≤5th percentile, second-trimester alpha-fetoprotein in the ≥95th percentile, and second-trimester inhibin in the ≥95th percentile (odds ratios, 2.3-3.6). In general, pregnancies in the subsequent cohort with a biomarker pattern that were found to be associated with early-preterm delivery in the first sample were at an increased risk for early-preterm birth and preterm birth in general (<37 weeks of gestation; adjusted RR, 1.6-27.4). Pregnancies with ≥2 biomarker abnormalities were at particularly increased risk (adjusted RR, 3.6-27.4).When considered across cohorts and in combination, abnormalities in routinely collected biomarkers reveal predictable risks for early-preterm birth.
View details for DOI 10.1016/j.ajog.2013.02.012
View details for Web of Science ID 000320596600029
View details for PubMedID 23395922
Congenital anomalies are a leading cause of infant mortality and are important contributors to subsequent morbidity. Studies suggest associations between environmental contaminants and some anomalies, although evidence is limited. We aimed to investigate whether ambient air pollutant and traffic exposures in early gestation contribute to the risk of selected congenital anomalies in the San Joaquin Valley of California, 1997-2006. Seven exposures and 5 outcomes were included for a total of 35 investigated associations. We observed increased odds of neural tube defects when comparing the highest with the lowest quartile of exposure for several pollutants after adjusting for maternal race/ethnicity, education, and multivitamin use. The adjusted odds ratio for neural tube defects among those with the highest carbon monoxide exposure was 1.9 (95% confidence interval: 1.1, 3.2) compared with those with the lowest exposure, and there was a monotonic exposure-response across quartiles. The highest quartile of nitrogen oxide exposure was associated with neural tube defects (adjusted odds ratio = 1.8, 95% confidence interval: 1.1, 2.8). The adjusted odds ratio for the highest quartile of nitrogen dioxide exposure was 1.7 (95% confidence interval: 1.1, 2.7). Ozone was associated with decreased odds of neural tube defects. Our results extend the limited body of evidence regarding air pollution exposure and adverse birth outcomes.
View details for DOI 10.1093/aje/kws367
View details for Web of Science ID 000318801200006
View details for PubMedID 23538941
Objective :? To evaluate whether there is an association between maternal occupational exposure to polycyclic aromatic hydrocarbons and oral clefts in offspring. This is the first human study of polycyclic aromatic hydrocarbons and clefts of which the authors are aware. Design :? Case-control study. Setting, Participants :? Data for 1997 to 2002 from the National Birth Defects Prevention Study, a large population-based case-control study in the United States, were analyzed. Maternal telephone interviews yielded information on jobs held in the month before through 3 months after conception. Two industrial hygienists independently assessed occupational exposure to polycyclic aromatic hydrocarbons; all jobs rated as exposed or with rating difficulty were reviewed with a third industrial hygienist to reach consensus on all exposure parameters. Logistic regression estimated crude and adjusted odds ratios with 95% confidence intervals for cleft lip with or without cleft palate and cleft palate alone. Results :? There were 2989 controls (3.5% exposed), 805 cases of cleft lip with or without cleft palate (5.8% exposed), and 439 cases of cleft palate alone (4.6% exposed). The odds of maternal occupational exposure to polycyclic aromatic hydrocarbons (any versus none) during pregnancy was increased for cleft lip with or without cleft palate cases as compared with controls (odds ratio, 1.69; 95% confidence interval, 1.18 to 2.40); the odds ratio was 1.47 (95% confidence interval 1.02 to 2.12) when adjusted for maternal education. There was a statistically significant adjusted exposure-response relationship for cleft lip with or without cleft palate (Ptrend = .02). Odd ratios for cleft palate alone were not statistically significant. Conclusions :? Maternal occupational exposure to polycyclic aromatic hydrocarbons was associated with increased risk of cleft lip with or without cleft palate in offspring.
View details for DOI 10.1597/12-104
View details for PubMedID 23136939
Medical researchers have called for new forms of translational science that can solve complex medical problems. Mainstream science has made complementary calls for heterogeneous teams of collaborators who conduct transdisciplinary research so as to solve complex social problems. Is transdisciplinary translational science what the medical community needs? What challenges must the medical community overcome to successfully implement this new form of translational science? This article makes several contributions. First, it clarifies the concept of transdisciplinary research and distinguishes it from other forms of collaboration. Second, it presents an example of a complex medical problem and a concrete effort to solve it through transdisciplinary collaboration: for example, the problem of preterm birth and the March of Dimes effort to form a transdisciplinary research center that synthesizes knowledge on it. The presentation of this example grounds discussion on new medical research models and reveals potential means by which they can be judged and evaluated. Third, this article identifies the challenges to forming transdisciplines and the practices that overcome them. Departments, universities and disciplines tend to form intellectual silos and adopt reductionist approaches. Forming a more integrated (or 'constructionist'), problem-based science reflective of transdisciplinary research requires the adoption of novel practices to overcome these obstacles.
View details for DOI 10.1038/jp.2012.133
View details for Web of Science ID 000316833300001
Small intestinal atresia (SIA) is a rare congenital occlusion of the small intestine. SIA development, particularly in the jejunum and ileum, has been associated with in utero disruption of vascular supply. However, the number of studies of the vascular hypothesis is limited. This study considers the vascular hypothesis by exploring risks associated with 32 SNPs of genes involved in vascular processes of homocysteine metabolism, coagulation, cell-cell interactions, inflammatory response, and blood pressure regulation. A total of 206 SIA cases were ascertained by the California Birth Defects Monitoring Program, and 573 infants with no major congenital anomalies by their first birthday were selected as controls. Genomic DNA was genotyped for 32 SNPs involving the following genes: MTHFR, F2, F5, F7, SERPINE1, FGB, ITGA2, ITGB3, SELE, ICAM1, MMP3, TNF, LTA, NOS3, AGTR1, AGT, NPPA, ADD1, SCNN1A, GNB3, and ADRB2. Risks were estimated as odds ratios, adjusted for maternal age and race, with 95% confidence intervals. Cases were considered collectively and by subgroups based on atresia location (duodenal/jejunum/ileum). Three SNPs had reduced risk: SERPINE1 11053 T/G, MMP3 (-1171) A6/A5, and ADRB2 gln27glu. Two had increased risk: ITGA2 873 G/A and NPPA 2238 T/C. No intestinal subphenotypes showed a unique pattern of SNP associations. The association of two SNPs with increased risk lends some, albeit limited, support to vascular impairment as a possible mechanism leading to SIA. These results also identify genes meriting further exploration in SIA studies. Hence, this study makes an important contribution by exploring the long-held but not well-investigated vascular hypothesis.
View details for DOI 10.1002/ajmg.a.35775
View details for Web of Science ID 000316631300012
View details for PubMedID 23444056
Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease in infants. Its treatment imposes considerable healthcare burden and costs in the perinatal and early childhood period and patients are usually left with lifelong deficits in lung function. Evidence exists for different pathophysiologic pathways that can promote the structural changes that characterize BPD, including the impairment in alveolarization; however, there is increasing interest regarding heritable factors that may predispose very low birth weight infants to BPD. Our review focuses on recent publications that have investigated genetic factors that may potentially contribute to such reported heritability. These publications point us toward some possible genomic candidates for further study, but certainly do not identify any particular gene or gene pathway that would be inferred to be contributing substantially to the underlying etiology of BPD.
View details for DOI 10.1053/j.semperi.2013.01.004
View details for Web of Science ID 000317870800005
View details for PubMedID 23582962
Human birth defects are a major public health burden: The Center for Disease Control estimates that 1 of every 33 United States newborns presents with a birth defect, and worldwide the estimate approaches 6% of all births. Among the most common and debilitating of human birth defects are those affecting the formation of the neural tube, the precursor to the central nervous system. Neural tube defects (NTDs) arise from a complex combination of genetic and environmental interactions. Although substantial advances have been made in the prevention and treatment of these malformations, NTDs remain a substantial public health problem, and we are only now beginning to understand their etiology. Here, we review the process of neural tube development and how defects in this process lead to NTDs, both in humans and in the animal models that serve to inform our understanding of these processes. The insights we are gaining will help generate new intervention strategies to tackle the clinical challenges and to alleviate the personal and societal burdens that accompany these defects.
View details for DOI 10.1126/science.1222002
View details for Web of Science ID 000315452000032
View details for PubMedID 23449594
Underlying mechanisms are unknown by which folic acid use in early pregnancy may reduce risks of orofacial clefts. Thymidylate synthase (TYMS) is a folate-dependent enzyme that catalyzes reductive methylation of deoxyuridylate to thymidylate, thereby playing a central role in DNA synthesis and repair. We investigated two TYMS functional variants (a 28-bp tandem repeat in the promoter enhancer region of the 5'-UTR; and TYMS 1494del6 (rs16430): a 6-bp deletion in the 3'-UTR) for their risk of cleft palate (CP) and of cleft lip with/without CP (CLP). We investigated effect measure modification between these variants and maternal folate intake for cleft risk.This case-control study included deliveries from July 1999 to June 2003 from select areas of California. Case groups included CLP or CP alone. Nonmalformed, liveborn controls were randomly selected. Maternal interviews provided information on vitamin use and dietary folate intake. DNA was derived from newborn bloodspots.Data were available for 304 CLP cases, 123 CP cases, and 581 controls. 1496del6 variants did not appear to influence risk of CP or CLP. Homozygosity for the 28-bp VNTR variant influenced CP risk (odds ratios, OR = 1.8, 95% confidence interval, 1.1-3.1), particularly among Hispanic infants, OR 2.1 (1.0-4.6). Effect measure modification was observed between the 28-bp VNTR and combined folate intake for CP with an OR of 10.0 (1.6-60.9).Although these findings are consistent with biological mechanisms, they were based on relatively small sample sizes and may represent false-positive discoveries. Replication is warranted in other populations.
View details for DOI 10.1002/bdra.23114
View details for Web of Science ID 000314982400004
View details for PubMedID 23404871
Spots of blood are routinely collected from newborn babies onto filter paper called Guthrie cards and used to screen for metabolic and genetic disorders. The archived dried blood spots are an important and precious resource for genomic research. Whole genome amplification of dried blood spot DNA has been used to provide DNA for genome-wide SNP genotyping. Here we describe a 96 well format procedure to extract DNA from a portion of a dried blood spot that provides sufficient unamplified genomic DNA for genome-wide single nucleotide polymorphism (SNP) genotyping. We show that SNP genotyping of the unamplified DNA is more robust than genotyping amplified dried blood spot DNA, is comparable in cost, and can be done with thousands of samples. This procedure can be used for genome-wide association studies and other large-scale genomic analyses that require robust, high-accuracy genotyping of dried blood spot DNA.
View details for DOI 10.1371/journal.pone.0064710
View details for PubMedID 23737996
A recent genome wide association study demonstrated the novel finding that variants in DGKK are associated with hypospadias. Our objectives were to determine whether this finding could be replicated in a more racially/ethnically diverse study population of California births and to provide a more comprehensive investigation of variants.We examined the association of 27 DGKK single nucleotide polymorphisms with hypospadias relative to population based nonmalformed controls born in selected California counties from 1990 to 2003. Analyses included a maximum of 928 controls and 665 cases (mild in 91, moderate in 336, severe in 221 and undetermined in 17). Results for mild and moderate cases were similar, so they were grouped together.For mild and moderate cases OR for 15 of the 27 single nucleotide polymorphisms had p values less than 0.05, with 2 less than 1 and the others ranging from 1.3 to 1.8. Among severe cases ORs tended to be closer to 1, and none of the p values were less than 0.05. Due to high linkage disequilibrium across the single nucleotide polymorphisms, haplotype analyses were conducted and 2 blocks were generated. These analyses identified a set of 8 variants associated with a threefold to fourfold increased risk relative to the most common haplotype, regardless of severity of the phenotype (OR 4.1, p <10(-4) for mild to moderate cases and 3.3, p = 0.001 for severe cases).This study confirms that DGKK variants are associated with hypospadias. Additional studies are needed to allow a more thorough investigation of DGKK variability and to delineate the mechanism by which DGKK contributes to urethral development.
View details for DOI 10.1016/j.juro.2012.09.002
View details for Web of Science ID 000312604800107
View details for PubMedID 23177175
Few studies have evaluated genetic susceptibility related to diabetes and obesity as a risk factor for neural tube defects (NTDs). The authors investigated 23 single nucleotide polymorphisms among 9 genes (ADRB3, ENPP1, FTO, LEP, PPARG, PPARGC1A, SLC2A2, TCF7L2, and UCP2) associated with type 2 diabetes or obesity. Samples were obtained from 737 NTD case-parent triads included in the National Birth Defects Prevention Study during 1999-2007. Log-linear models were used to evaluate maternal and offspring genetic effects. After application of the false discovery rate, there were 5 significant maternal genetic effects. The less common alleles at the 4 FTO single nucleotide polymorphisms showed a reduction of NTD risk (for rs1421085, relative risk (RR) = 0.73 (95% confidence interval (CI): 0.62, 0.87); for rs8050136, RR = 0.79 (95% CI: 0.67, 0.93); for rs9939609, RR = 0.79 (95% CI: 0.67, 0.94); and for rs17187449, RR = 0.80 (95% CI: 0.68, 0.95)). Additionally, maternal LEP rs2071045 (RR = 1.31, 95% CI: 1.08, 1.60) and offspring UCP2 rs660339 (RR = 1.32, 95% CI: 1.06, 1.64) were associated with NTD risk. Furthermore, the maternal genotype for TCF7L2 rs3814573 suggested an increased NTD risk among obese women. These findings indicate that maternal genetic variants associated with glucose homeostasis may modify the risk of having an NTD-affected pregnancy.
View details for DOI 10.1093/aje/kws190
View details for Web of Science ID 000312634900006
View details for PubMedID 23132673
Prepregnancy diabetes and obesity have been identified as independent risk factors for several birth defects, providing support for a mechanism that involves hyperglycemia and hyperinsulinemia in the development of malformations. Data from the National Birth Defects Prevention Study from 1997 to 2007 were used to investigate the association between the maternal dietary glycemic index (DGI) and the risk of birth defects among nondiabetic women. DGI was categorized by using spline regression models and quartile distributions. Adjusted odds ratios and 95% confidence intervals were calculated. The joint effect of DGI and obesity was also examined. Among the 53 birth defects analyzed, high DGI, categorized by spline regression, was significantly associated with encephalocele (adjusted odds ratio (aOR) = 2.68), diaphragmatic hernia (aOR = 2.58), small intestinal atresia/stenosis (aOR = 2.97) including duodenal atresia/stenosis (aOR = 2.48), and atrial septal defect (aOR = 1.37). Using quartiles to categorize DGI, the authors identified associations with cleft lip with cleft palate (aOR = 1.23) and anorectal atresia/stenosis (aOR = 1.40). The joint effect of high DGI and obesity provided evidence of a synergistic effect on the risk of selected birth defects. High DGI is associated with an increased risk of a number of birth defects under study. Obesity coupled with high DGI appears to increase the risk further for some birth defects.
View details for DOI 10.1093/aje/kws201
View details for Web of Science ID 000312634900007
View details for PubMedID 23171874
To evaluate trends in survival among children with spina bifida by race/ethnicity and possible prognostic factors in 10 regions of the United States.A retrospective cohort study was conducted of 5165 infants with spina bifida born during 1979-2003, identified by 10 birth defects registries in the United States. Survival probabilities and adjusted hazard ratios were estimated for race/ethnicity and other characteristics using the Cox proportional hazard model.During the study period, the 1-year survival probability among infants with spina bifida showed improvements for whites (from 88% to 96%), blacks (from 79% to 88%), and Hispanics (from 88% to 93%). The impact of race/ethnicity on survival varied by birth weight, which was the strongest predictor of survival through age 8. There was little racial/ethnic variation in survival among children born of very low birth weight. Among children born of low birth weight, the increased risk of mortality to Hispanics was approximately 4-6 times that of whites. The black-white disparity was greatest among children born of normal birth weight. Congenital heart defects did not affect the risk of mortality among very low birth weight children but increased the risk of mortality 4-fold among children born of normal birth weight.The survival of infants born with spina bifida has improved; however, improvements in survival varied by race/ethnicity, and blacks and Hispanics continued to have poorer survival than whites in the most recent birth cohort from 1998-2002. Further studies are warranted to elucidate possible reasons for the observed differences in survival.
View details for DOI 10.1016/j.jpeds.2012.05.040
View details for Web of Science ID 000311348400032
View details for PubMedID 22727874
To test the hypothesis that the weight-for-stature (WFS) and BMI methods are not equivalent in determining expected body weight (EBW) in adolescents with eating disorders and to determine the sensitivity, specificity, and positive predictive value of each method to detect those <75% EBW. We hypothesized that differences in EBW would be greatest at the extremes of height.EBW was determined for 12 047 individual adolescents aged 12 to 19 years by the WFS and BMI methods by utilizing the same National Center for Health Statistics data sets. Absolute difference between the 2 methods for each individual was calculated and plotted against height by using a generalized additive model. The number of individuals whose weights were <75% EBW was determined by each method.For girls, EBW was 3.52 ± 3.13% higher when using the WFS method compared with the BMI method. For boys, EBW(WFS) was 3.45 ± 2.72% higher than EBW(BMI). Among adolescent girls, 65% had EBW(WFS) higher than EBW(BMI). By using the EBW(WFS) method as the gold standard, specificity of the EBW(BMI) method to detect those <75% EBW was 0.999, but sensitivity was only 0.329. Absolute differences in EBW were most pronounced at the extremes of height.The WFS and BMI methods are not equivalent in determining EBW in adolescents and are not interchangeable. EBW(WFS) was ~3.5% higher than EBW(BMI). In adolescents with eating disorders, use of the BMI method will underestimate the degree of malnutrition compared with the WFS method. Which method better predicts meaningful clinical outcomes remains to be determined.
View details for DOI 10.1542/peds.2012-0897
View details for Web of Science ID 000314802000024
View details for PubMedID 23147977
Few studies have investigated the potential association of maternal dietary intake and risk of microtia among offspring.The study included deliveries from 1997 to 2005 from the National Birth Defects Prevention Study. Nonsyndromic cases of microtia were compared to nonmalformed, population-based, live-born control infants by estimating adjusted odds ratios (ORs) and 95% confidence intervals (CIs) from logistic regression models that included maternal race or ethnicity, education, folic acid-containing supplement intake, fertility treatment, study site, and total energy intake.Comparing intake in the lowest 10th percentile versus the 10th to 90th percentiles, lower maternal intakes of carbohydrate (OR, 1.59; 95% CI, 1.07-2.38) and dietary folate (OR, 1.57; 95% CI, 1.09-2.25) were associated with elevated risk of microtia. In addition, results suggested that higher diet quality (as measured by the Diet Quality Index, and comparing the highest with the lowest quartile) was protective, but the CI did not exclude one (OR, 0.73; 95% CI, 0.50-1.07). Results were similar among obese and nonobese women.These data contribute to the limited body of evidence regarding the potential contribution of maternal nutrition to the etiology of microtia.
View details for DOI 10.1002/bdra.23053
View details for Web of Science ID 000312527100010
View details for PubMedID 22821770
Limited information is available about the association of maternal weight gain during pregnancy and birth defects. The objective of this study was to investigate the association of maternal weight gain with neural tube defects (NTDs) and gastroschisis among offspring.We used data from the National Birth Defects Prevention Study, an ongoing multicenter, population-based, case-control study. Mothers of cases and controls were interviewed by telephone. Analyses included 255 anencephaly, 577 spina bifida, 648 gastroschisis cases, and 5587 controls with deliveries from 1999 to 2005. After subtracting birth weight, the associations of total and average weekly weight gain (kg) with each phenotype were estimated, stratified by gestational age (<37 vs. ?37 weeks) and adjusted for relevant covariates.Among deliveries <37 weeks gestation, mothers of infants with anencephaly and spina bifida had lower weight gains compared to control mothers; no association between weight gains and gastroschisis was observed. Among deliveries ?37 weeks, mothers of infants with anencephaly had lower weight gains during pregnancy; a similar association was not observed for spina bifida; mothers of infants with gastroschisis were twice as likely to have weight gains in the highest quartile. Stratification by maternal age (gastroschisis) or body mass index (BMI) or race/ethnicity (all phenotypes) did not alter odds ratio estimates.Altered weight gain during pregnancy may be a consequence of carrying an NTD/gastroschisis affected fetus or a marker for underlying factors common to the etiology of these birth defects. It is possible that whatever mechanisms influence weight gain may also influence the development of NTDs and gastroschisis, but in opposite directions.
View details for DOI 10.1002/bdra.23057
View details for Web of Science ID 000312527100009
View details for PubMedID 22847944
There is evidence in experimental model systems that exposure to polycyclic aromatic hydrocarbons (PAHs) results in congenital heart defects (CHDs); however, to our knowledge, this relationship has not been examined in humans. Therefore, we conducted a case-control study assessing the association between estimated maternal occupational exposure to PAHs and CHDs in offspring.Data on CHD cases and control infants were obtained from the National Birth Defects Prevention Study for the period of 1997 to 2002. Exposure to PAHs was assigned by industrial hygienist consensus, based on self-reported maternal occupational histories from 1 month before conception through the third month of pregnancy. Logistic regression was used to evaluate the association between maternal occupational PAH exposure and specific CHD phenotypic subtypes among offspring.The prevalence of occupational PAH exposure was 4.0% in CHD case mothers (76/1907) and 3.6% in control mothers (104/2853). After adjusting for maternal age, race or ethnicity, education, smoking, folic acid supplementation, and study center, exposure was not associated with conotruncal defects (adjusted odds ratio [AOR], 0.98; 95% confidence interval [CI], 0.58-1.67), septal defects (AOR, 1.28; 95% CI, 0.86-1.90), or with any isolated CHD subtype.Our findings do not support an association between potential maternal occupational exposure to PAHs and various CHDs in a large, population-based study. For CHD phenotypic subtypes in which modest nonsignificant associations were observed, future investigations could be improved by studying populations with a higher prevalence of PAH exposure and by incorporating information on maternal and fetal genotypes related to PAH metabolism. Birth Defects Research (Part A), 2012.
View details for DOI 10.1002/bdra.23071
View details for Web of Science ID 000311234400003
View details for PubMedID 22945317
Tetrahydrobiopterin (BH(4)) is an essential cofactor and an important cellular antioxidant. BH(4) deficiency has been associated with diseases whose etiologies stem from excessive oxidative stress. GTP cyclohydrolase I (GCH1) catalyzes the first and rate-limiting step of de novo BH(4) synthesis. A 3-SNP haplotype in GCH1 (rs8007267, rs3783641, and rs10483639) is known to modulate GCH1 gene expression levels and has been suggested as a major determinant of plasma BH(4) bioavailability. As plasma BH(4) bioavailability has been suggested as a mechanism of neural tube defect (NTD) teratogenesis, we evaluated the association between this GCH1 haplotype and the risk of NTDs. Samples were obtained from 760 NTD case-parent triads included in the National Birth Defects Prevention Study (NBDPS). The three SNPs were genotyped using TaqMan® SNP assays. An extension of the log-linear model was used to assess the association between NTDs and both offspring and maternal haplotypes. Offspring carrying two copies of haplotype C-T-C had a significantly increased NTD risk (risk ratio [RR]=3.40, 95% confidence interval [CI]: 1.02-11.50), after adjusting for the effect of the maternal haplotype. Additionally, mothers carrying two copies of haplotype C-T-C had a significantly increased risk of having an NTD-affected offspring (RR=3.46, 95% CI: 1.05-11.00), after adjusting for the effect of the offspring haplotype. These results suggest offspring and maternal variation in the GCH1 gene and altered BH(4) biosynthesis may contribute to NTD risk.
View details for DOI 10.1016/j.ymgme.2012.09.020
View details for Web of Science ID 000310720200050
View details for PubMedID 23059057
Maternal nutritional status has been evaluated to clarify its role in development of neural tube defects (NTDs). Maternal folate intake during pregnancy has been closely evaluated for its association with NTDs. The study objective was to examine associations between NTDs and other dietary periconceptional micronutrient intake, particularly nutrients involved in one-carbon metabolism or antioxidant activity.Using data from the National Birth Defects Prevention Study, 1997-2005, logistic regression models were used to estimate the relative risk of NTDs based on maternal micronutrient intake.Results were stratified according to folic acid supplement use, race/ethnicity, and maternal body mass index. Analyses included 954 cases (300 with anencephaly, 654 with spina bifida) and 6268 controls. Higher intakes of folate, thiamin, betaine, iron, and vitamin A were associated with decreased risk of anencephaly among some ethnic and clinical groups. In some groups, higher intakes of thiamin, riboflavin, vitamin B(6) , vitamin C, vitamin E, niacin, and retinol were associated with decreased risk of spina bifida.In addition to folic acid, other micronutrients, including thiamin, betaine, riboflavin, vitamin B(6) , vitamin C, vitamin E, niacin, iron, retinol, and vitamin A, may decrease the risk of NTD occurrence. Birth Defects Research (Part A) 2012. © 2012 Wiley Periodicals, Inc.
View details for DOI 10.1002/bdra.23068
View details for Web of Science ID 000311234400002
View details for PubMedID 22933447
Although the descriptive epidemiology of atrioventricular septal defects (AVSDs), a group of serious congenital heart defects (CHDs), has been recently reported, non-genetic risk factors have not been consistently identified. Using data (1997-2005) from the National Birth Defects Prevention Study, an ongoing multisite population-based case-control study, the association between selected non-genetic factors and non-syndromic AVSDs was examined. Data on periconceptional exposures to such factors were collected by telephone interview from 187 mothers of AVSD case infants and 6,703 mothers of unaffected infants. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated from logistic regression models. Mothers who reported cigarette smoking during the periconceptional period were more likely to have infants with AVSDs compared with non-smokers, independent of maternal age, periconceptional alcohol consumption, infant gestational age, family history of CHDs, and study site (aOR 1.5, 95% CI 1.1-2.4). The association was strongest in mothers who smoked more than 25 cigarettes/day. In addition, mothers with periconceptional passive smoke exposure were more likely to have infants with AVSDs than unexposed mothers, independent of maternal age, active periconceptional smoking, infant gestational age, and family history of CHDs (aOR 1.4, 95% CI 1.0-2.0). No associations were observed between AVSDs and maternal history of a urinary tract infection or pelvic inflammatory disease, maternal use of a wide variety of medications, maternal occupational exposure, parental drug use, or maternal alcohol consumption. If the results of this preliminary study can be replicated, minimizing maternal active and passive smoke exposure may decrease the incidence of AVSDs.
View details for DOI 10.1002/ajmg.a.35555
View details for Web of Science ID 000310070700012
Spina bifida is one of the most common of all human structural birth defects. Despite considerable effort over several decades, the causes and mechanisms underlying this malformation remain poorly characterized.To better understand the pathogenesis of this abnormality, we conducted a microarray study using Mouse Whole Genome Bioarrays which have ~36,000 gene targets, to compare gene expression profiles between two mouse models; CXL-Splotch and FKBP8(Gt(neo)) which express a similar spina bifida phenotype. We anticipated that there would be a collection of overlapping genes or shared genetic pathways at the molecular level indicative of a common mechanism underlying the pathogenesis of spina bifida during embryonic development.A total of 54 genes were determined to be differentially expressed (25 downregulated, 29 upregulated) in the FKBP8Gt((neo)) mouse embryos; whereas 73 genes were differentially expressed (56 downregulated, 17 upregulated) in the CXL-Splotch mouse relative to their wild-type controls. Remarkably, the only two genes that showed decreased expression in both mutants were v-ski sarcoma viral oncogene homolog (Ski), and Zic1, a transcription factor member of the zinc finger family. Confirmation analysis using quantitative real-time (qRT)-PCR indicated that only Zic1 was significantly decreased in both mutants. Gene ontology analysis revealed striking enrichment of genes associated with mesoderm and central nervous system development in the CXL-Splotch mutant embryos, whereas in the FKBP8(Gt(neo)) mutants, the genes involved in dorsal/ventral pattern formation, cell fate specification, and positive regulation of cell differentiation were most likely to be enriched. These results indicate that there are multiple pathways and gene networks perturbed in mouse embryos with shared phenotypes.
View details for DOI 10.1002/bdra.23081
View details for Web of Science ID 000310068400006
View details for PubMedID 23024056
Neural tube defects (NTDs) are common, serious malformations with a complex etiology that suggests involvement of both genetic and environmental factors. The authors evaluated maternal or offspring folate-related gene variants and interactions between the gene variants and maternal intake of folates on the risk of NTDs in their offspring. A case-control study was conducted on mothers and/or their fetuses and infants who were born in California from 1999 to 2003 with an NTD (cases n = 222, including 24 mother-infant pairs) or without a major malformation (controls n = 454, including 186 mother-infant pairs). Maternal intake of folates was assessed by food frequency questionnaire and genotyping was performed on samples from mothers and infants. For mothers in the lowest folate-intake group, risk of NTDs in offspring was significantly decreased for maternal MTHFR SNPs rs1476413, rs1801131, and rs1801133 (odds ratio [OR] = 0.55, 80% confidence interval [CI]: 0.20, 1.48; OR = 0.58, 80% CI: 0.24, 1.43; OR = 0.69, 80% CI: 0.41, 1.17, respectively), and TYMS SNPs rs502396 and rs699517 (OR = 0.91, 80% CI: 0.53, 1.56; OR = 0.70, 80% CI: 0.38, 1.29). A gene-only effect was observed for maternal SHMT1 SNP rs669340 (OR?=?0.69, 95% CI: 0.49, 0.96). When there was low maternal folate intake, risk of NTDs was significantly increased for infant MTHFD1 SNPs rs2236224, rs2236225, and rs11627387 (OR = 1.58, 80% CI: 0.99, 2.51; OR = 1.53, 80% CI: 0.95, 2.47; OR = 4.25, 80% CI: 2.33, 7.75, respectively) and SHMT1 SNP rs12939757 (OR = 2.01, 80% CI: 1.20, 3.37), but decreased for TYMS SNP rs2847153 (OR = 0.73, 80% CI: 0.37, 1.45). Although power to detect interaction effects was low for this birth defects association study, the gene-folate interactions observed in this study represent preliminary findings that will be useful for informing future studies on the complex etiology of NTDs.
View details for DOI 10.1002/ajmg.a.35552
View details for Web of Science ID 000310070700011
View details for PubMedID 22903727
This study evaluated whether there is an association between maternal occupational exposure to polycyclic aromatic hydrocarbons (PAHs) and neural tube defects (NTDs) in offspring. This is the first such study of which the authors are aware.Data were analyzed from 1997 to 2002 deliveries in the National Birth Defects Prevention Study, a large population-based case-control study in the United States. Maternal interviews yielded information on jobs held in the month before through 3 months after conception. Three industrial hygienists blinded to case or control status assessed occupational exposure to PAHs. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using unconditional logistic regression.Of the 520 mothers of children with NTDs, 5.0% were classified as exposed to occupational PAHs, as were 3.5% of the 2989 mothers of controls. The crude OR for PAH exposure was 1.43 (95% CI, 0.92-2.22) for any NTD and 1.71 (95% CI, 1.03-2.83) for spina bifida. Adjusted ORs were smaller in magnitude and not significant. Among women who were normal weight or underweight, the crude OR for spina bifida was 3.13 (95% CI, 1.63-6.03) and adjusted OR was 2.59 (95% CI, 1.32-5.07). Based on estimated cumulative exposure, a statistically significant dose-response trend was observed for spina bifida; however, it was attenuated and no longer significant after adjustment.Maternal occupational exposure to PAHs may be associated with increased risk of spina bifida in offspring among women who are normal weight or underweight. Other comparisons between PAHs and NTDs were consistent with no association.
View details for DOI 10.1002/bdra.23045
View details for Web of Science ID 000308473800003
View details for PubMedID 22807044
In this study, we investigated whether the two TYMS functional variants (28?bp VNTR and 1494del6) (275 cases and 653 controls) and six selected SNPs (265 case infants, 535 control infants; 169 case mothers and 276 control mothers) were associated with risks of conotruncal heart defects. Further, we evaluated interaction effects between these gene variants and maternal folate intake for risk of CTD. Cases with diagnosis of single gene disorders or chromosomal aneusomies were excluded. Controls were randomly selected from area hospitals in proportion to their contribution to the total population of live-born infants. DNA samples were collected using buccal brushes or drawn from the repository of newborn screening blood specimens when available. Genetic variants were treated as categorical variables (homozygous referent, heterozygote, homozygous variant). Odds ratios and 95% confidence intervals (CI) were computed to estimate risks among all subjects, Hispanic and non-Hispanic whites, respectively, using logistic regression. Gene-folate interactions were assessed for these variants by adding an interaction term to the logistic model. A dichotomized composite variable, "combined folate intake," was created by combining maternal peri-conceptional use of folic acid-containing vitamin supplements with daily dietary intake of folate. In general, the results do not show strong gene-only effects on risk of CTD. We did, however, observe a 3.6-fold increase in CTD risk (95% CI: 1.1-11.9) among infants who were homozygotes for the 6?bp deletion in the 3'-untranslated region (UTR) (1694del6) and whose mothers had low folate intake during the peri-conceptional period.
View details for DOI 10.1002/ajmg.a.35310
View details for Web of Science ID 000310068700015
View details for PubMedID 22887475
This review evaluates current knowledge related to trends in the prevalence of hypospadias, the association of hypospadias with endocrine-disrupting exposures, and the potential contribution of genetic susceptibility to its etiology. The review focuses on epidemiologic evidence. Increasing prevalence of hypospadias has been observed, but such increases tend to be localized to specific regions or time periods. Thus, generalized statements that hypospadias is increasing are unsupported. Owing to the limitations of study designs and inconsistent results, firm conclusions cannot be made regarding the association of endocrine-disrupting exposures with hypospadias. Studies with more rigorous study designs (e.g., larger and more detailed phenotypes) and exposure assessment that encompasses more breadth and depth (e.g., specific endocrine-related chemicals) will be critical to make better inferences about these important environmental exposures. Many candidate genes for hypospadias have been identified, but few of them have been examined to an extent that enables solid conclusions. Further study is needed that includes larger sample sizes, comparison groups that are more representative of the populations from which the cases were derived, phenotype-specific analyses, and more extensive exploration of variants. In conclusion, examining the associations of environmental and genetic factors with hypospadias remain important areas of inquiry, although our actual understanding of their contribution to hypospadias risk in humans is currently limited.
View details for DOI 10.1002/bdra.23021
View details for Web of Science ID 000306186100001
View details for PubMedID 22678668
We examined whether hypospadias was associated with several aspects of the diet, including intake of animal products, intake of several nutrients and food groups related to a vegetarian diet and oestrogen metabolism, and diet quality.The study included deliveries from 1997 to 2005 that were part of the National Birth Defects Prevention Study. Diet was assessed by food frequency questionnaire during maternal telephone interviews, and two diet quality indices were developed based on existing indices. Analyses included 1250 cases with second- or third-degree hypospadias (urethra opened at the penile shaft, scrotum or perineum) and 3118 male, liveborn, non-malformed controls. All odds ratios (OR) and 95% confidence intervals [CI] were estimated from logistic regression models that included several potential confounders, including energy intake.Intake of animal products was not associated with hypospadias; for example, the adjusted OR for any vs. no intake of meat was 1.0 [95% CI 0.6, 1.6]. Frequency of intake of meat or other animal products was also not associated with hypospadias, nor was intake of iron or several nutrients that are potentially related to oestrogen metabolism. Diet quality was also not associated with hypospadias; the OR for diet quality in the highest vs. lowest quartile for the two diet quality indices were 1.0 [95% CI 0.6, 1.6] and 0.9 [95% CI 0.7, 1.1].This large study does not support an association of a vegetarian diet or worse diet quality with hypospadias.
View details for DOI 10.1111/j.1365-3016.2012.01272.x
View details for Web of Science ID 000305121500013
View details for PubMedID 22686387
To examine whether the incidence of childhood cancer is elevated in children with birth defects but no chromosomal anomalies.We examined cancer risk in a population-based cohort of children with and without major birth defects born between 1988 and 2004, by linking data from the California Birth Defects Monitoring Program, the California Cancer Registry, and birth certificates. Cox proportional hazards models generated hazard ratios (HRs) and 95% CIs based on person-years at risk. We compared the risk of childhood cancer in infants born with and without specific types of birth defects, excluding infants with chromosomal anomalies.Of the 4869 children in the birth cohort with cancer, 222 had a major birth defect. Although the expected elevation in cancer risk was observed in children with chromosomal birth defects (HR, 12.44; 95% CI, 10.10-15.32), especially for the leukemias (HR, 28.99; 95% CI, 23.07-36.42), children with nonchromosomal birth defects also had an increased risk of cancer (HR, 1.58; 95% CI, 1.33-1.87), but instead for brain tumors, lymphomas, neuroblastoma, and germ cell tumors.Children with nonchromosomal birth defects are at increased risk for solid tumors, but not leukemias. Dysregulation of early human development likely plays an important role in the etiology of childhood cancer.
View details for DOI 10.1016/j.jpeds.2011.12.006
View details for Web of Science ID 000304377300019
View details for PubMedID 22244463
Exposure to polycyclic aromatic hydrocarbons (PAHs) occurs in many occupational settings. There is evidence in animal models that maternal exposure to PAHs during pregnancy is associated with gastroschisis in offspring; however, to our knowledge, no human studies examining this association have been conducted.Our goal was to conduct a case-control study assessing the association between estimated maternal occupational exposure to PAHs and gastroschisis in offspring.Data from gastroschisis cases and control infants were obtained from the population-based National Birth Defects Prevention Study for the period 1997-2002. Exposure to PAHs was assigned by industrial hygienist consensus, based on self-reported maternal occupational histories from 1 month before conception through the third month of pregnancy. Logistic regression was used to determine the association between estimated occupational PAH exposure and gastroschisis among children whose mothers were employed for at least 1 month during the month before conception through the third month of pregnancy.The prevalence of estimated occupational PAH exposure was 9.0% in case mothers (27 of 299) and 3.6% in control mothers (107 of 2,993). Logistic regression analyses indicated a significant association between occupational PAHs and gastroschisis among mothers ? 20 years of age [odds ratio (OR) = 2.53; 95% confidence interval (CI): 1.27, 5.04] after adjusting for maternal body mass index, education, gestational diabetes, and smoking. This association was not seen in mothers < 20 years (OR = 1.14; 95% CI: 0.55, 2.33), which is notable because although young maternal age is the strongest known risk factor for gastroschisis, most cases are born to mothers ? 20 years.Our findings indicate an association between occupational exposure to PAHs among mothers who are ? 20 years and gastroschisis. These results contribute to a body of evidence that PAHs may be teratogenic.
View details for DOI 10.1289/ehp.1104305
View details for Web of Science ID 000304765700034
View details for PubMedID 22330681
We evaluated 35 variants among four folate-mediated one-carbon metabolism pathway genes, MTHFD1, SHMT1, MTHFR, and DHFR as risk factors for conotruncal heart defects. Cases with a diagnosis of single gene disorders or chromosomal aneusomies were excluded. Controls were randomly selected from area hospitals in proportion to their contribution to the total population of live-born infants. Odds ratios (OR) and the 95% confidence intervals (CI) were computed for each genotype (homozygous variant or heterozygote, vs. homozygous wildtype) and for increase of each less common allele (log-additive model). Interactions between each variant and three folate intake variables (maternal multivitamin use, maternal dietary folate intake, and combined maternal folate intake) were also evaluated under the log-additive model. In general, we did not identify notable associations. The A allele of MTHFD1 rs11627387 was associated with a 1.7-fold increase in conotruncal defects risk in both Hispanic mothers (OR = 1.7, 95% CI = 1.1-2.5) and Hispanic infants (OR = 1.7, 95% CI = 1.2-2.3). The T allele of MTHFR rs1801133 was associated with a 2.8-fold increase of risk among Hispanic women whose dietary folate intake was ? 25th centile. The C allele of MTHFR rs1801131 was associated with a two-fold increase of risk (OR = 2.0, 95% CI = 1.0-3.9) only among those whose dietary folate intake was >25th centile. Our study suggested that MTHFD1 rs11627387 may be associated with risk of conotruncal defects through both maternal and offspring genotype effect among the Hispanics. Maternal functional variants in MTHFR gene may interact with dietary folate intake and modify the conotruncal defects risk in the offspring.
View details for DOI 10.1002/ajmg.a.35313
View details for Web of Science ID 000303000200022
View details for PubMedID 22495907
Although maternal serum ?-fetoprotein (AFP), human chorionic gonandotropin (hCG), and estriol play important roles in immunomodulation and immunoregulation during pregnancy, their relationship with the development of bronchopulmonary dysplasia (BPD) in young infants is unknown despite BPD being associated with pre- and postnatal inflammatory factors.We found that these serum biomarkers were associated with an increased risk of BPD. Risks were especially high when AFP and/or hCG levels were above the 95th percentile and/or when unconjugated estriol (uE3) levels were below the 5th percentile (relative risks (RRs) 3.1-6.7). Risks increased substantially when two or more biomarker risks were present (RRs 9.9-75.9).Data suggested that pregnancies that had a biomarker risk and yielded an offspring with BPD were more likely to have other factors present that suggested early intrauterine fetal adaptation to stress, including maternal hypertension and asymmetric growth restriction.The objective of this population-based study was to examine whether second-trimester levels of AFP, hCG, and uE3 were associated with an increased risk of BPD.
View details for DOI 10.1038/pr.2011.73
View details for Web of Science ID 000301884500013
View details for PubMedID 22391642
This study examined the association between paternal age and a wide range of structural birth defects. Data were drawn from The California Birth Defects Monitoring Program, a population-based active surveillance system for collecting information on infants and fetuses with defects born between 1989 and 2002. The analysis included 46,114 cases with defects, plus a random sample of 36,838 non-malformed births. After adjustment for maternal age, risks of anomalies of the nervous system for 38 and 42 year-old fathers, as compared to 29 year-old fathers, were 1.05-fold [1.00, 1.11] and 1.10-fold [1.02, 1.18] higher, respectively. Similar results were observed for anomalies of the limbs, where 38 and 42 year-old fathers had a 1.06-fold [1.02, 1.11] and 1.11-fold [1.05, 1.18] higher risk, respectively. Risks of anomalies of the integument were 1.05-fold [1.00, 1.09] and 1.10-fold [1.03, 1.16] higher for 38 and 42 year olds, respectively. Young paternal age, i.e., less than 29 years, was associated with an increased risk of amniotic bands (OR: 0.87 [0.78, 0.97]), pyloric stenosis (OR: 0.93 [0.90, 0.96]) and anomalies of the great veins (OR: 0.93 [0.87, 1.00]). In sum, both advanced and young paternal age was associated with select birth defects in California between 1989 and 2002.
View details for DOI 10.1007/s10995-011-0759-z
View details for Web of Science ID 000299370400013
View details for PubMedID 21344170
Vax1 and Vax2 have been implicated in eye development and the closure of the choroid fissure in mice and zebrafish. We sequenced the coding exons of VAX1 and VAX2 in 70 patients with anophthalmia/microphthalmia (A/M). In VAX1, we observed homozygosity for two successive nucleotide substitutions c.453G>A and c.454C>A, predicting p.Arg152Ser, in a proband of Egyptian origin with microphthalmia, small optic nerves, cleft lip/palate, and corpus callosum agenesis. This mutation affects an invariant residue in the homeodomain of VAX1 and was absent from 96 Egyptian controls. It is likely that the mutation results in a loss of function, as the mutation results in a phenotype similar to the Vax1 homozygous null mouse. We did not identify any mutations in VAX2. This is the first description of a phenotype associated with a VAX1 mutation in humans and establishes VAX1 as a new causative gene for A/M.
View details for DOI 10.1002/humu.21658
View details for Web of Science ID 000300705600012
View details for PubMedID 22095910
To examine whether better maternal diet quality was associated with reduced risk for selected birth defects.A multicenter, population-based case-control study, the National Birth Defects Prevention Study.Ten participating centers in the United States.Eligible subjects' estimated due dates were from October 1997 through December 2005. Telephone interviews were conducted with 72% of case and 67% of control mothers. Analyses included 936 cases with neural tube defects (NTDs), 2475 with orofacial clefts, and 6147 nonmalformed controls.Food-frequency data were used to calculate the Mediterranean Diet Score (MDS) and Diet Quality Index (DQI), modeled after existing indices.Adjusted odds ratios (ORs).After covariate adjustment, increasing diet quality based on either index was associated with reduced risks for the birth defects studied. The strongest association was between anencephaly and DQI; the OR for highest vs lowest quartile was 0.49 (95% CI, 0.31-0.75). The ORs for cleft lip with or without cleft palate and cleft palate and DQI were also notable (0.66 [95% CI, 0.54-0.81] and 0.74 [95%CI, 0.56-0.96], respectively).Healthier maternal dietary patterns, as measured by diet quality scores, were associated with reduced risks of NTDs and clefts. These results suggest that dietary approaches could lead to further reduction in risks of major birth defects and complement existing efforts to fortify foods and encourage periconceptional multivitamin use.
View details for DOI 10.1001/archpediatrics.2011.185
View details for Web of Science ID 000301211000002
View details for PubMedID 21969361
Spina bifida refers to a collection of neural tube defects, including myelomeningocele, meningocele, and myelocele (SB(M) ), as well as lipomyelomeningocele and lipomeningocele (SB(L) ). Maternal race/ethnicity has been associated with an increased risk for spina bifida among offspring. To better understand this relationship, we evaluated different spina bifida subtypes (SB(M) vs. SB(L) ) and sub-phenotypes (anatomic level or presence of additional malformations) by maternal race/ethnicity using data from the National Birth Defects Prevention Study. This study is a large, multisite, population-based study of nonsyndromic birth defects. Prevalence estimates were obtained using data from spina bifida cases (live births, fetal deaths, and elective terminations) and total live births in the study regions. From October 1997 through December 2005, 1,046 infants/fetuses with spina bifida were delivered, yielding a prevalence of 3.06 per 10,000 live births. Differences in the prevalences of SB(M) vs. SB(L) , isolated versus non-isolated SB(M) , and lesion level in isolated SB(M) among case offspring were observed by maternal race/ethnicity. Compared to non-Hispanic (NH) White mothers, offspring of Hispanic mothers had higher prevalences of each subtype and most sub-phenotypes, while offspring of NH Black mothers generally had lower prevalences. Furthermore, differences in race/ethnicity among those with isolated SB(M) were more pronounced by sex. For instance, among male offspring, the prevalence of isolated SB(M) was significantly higher for those with Hispanic mothers compared to NH White mothers [prevalence ratio (PR): 1.55, 95% confidence interval: 1.23-1.95]. These findings provide evidence that certain spina bifida subtypes and sub-phenotypes may be etiologically distinct.
View details for DOI 10.1002/ajmg.a.34383
View details for Web of Science ID 000299381800016
View details for PubMedID 22140002
Despite compelling epidemiological evidence that folic acid supplements reduce the frequency of neural tube defects (NTDs) in newborns, common variant association studies with folate metabolism genes have failed to explain the majority of NTD risk. The contribution of rare alleles as well as genetic interactions within the folate pathway have not been extensively studied in the context of NTDs. Thus, we sequenced the exons in 31 folate-related genes in a 480-member NTD case-control population to identify the full spectrum of allelic variation and determine whether rare alleles or obvious genetic interactions within this pathway affect NTD risk. We constructed a pathway model, predetermined independent of the data, which grouped genes into coherent sets reflecting the distinct metabolic compartments in the folate/one-carbon pathway (purine synthesis, pyrimidine synthesis, and homocysteine recycling to methionine). By integrating multiple variants based on these groupings, we uncovered two provocative, complex genetic risk signatures. Interestingly, these signatures differed by race/ethnicity: a Hispanic risk profile pointed to alterations in purine biosynthesis, whereas that in non-Hispanic whites implicated homocysteine metabolism. In contrast, parallel analyses that focused on individual alleles, or individual genes, as the units by which to assign risk revealed no compelling associations. These results suggest that the ability to layer pathway relationships onto clinical variant data can be uniquely informative for identifying genetic risk as well as for generating mechanistic hypotheses. Furthermore, the identification of ethnic-specific risk signatures for spina bifida resonated with epidemiological data suggesting that the underlying pathogenesis may differ between Hispanic and non-Hispanic groups.
View details for DOI 10.1371/journal.pone.0028408
View details for Web of Science ID 000298168100069
View details for PubMedID 22140583
We investigated multiple sources of folate and folic acid to determine whether their periconceptional intakes were associated with preterm delivery. Studied were controls from the National Birth Defects Prevention Study delivered September 1998 to December 2005. Telephone interviews were conducted with 5952 (68% of eligible) mothers. Women were queried about intake of vitamin supplements in the 12 weeks before conception through delivery. A version of the Nurse's Health Study food frequency questionnaire was used to assess food sources. Eight percent of infants ( N?=?487) were preterm (<37 weeks). Compared with women who began intake of supplements with folic acid before pregnancy, those who began any time during pregnancy had an ~20% lowered risk of preterm delivery. Lower dietary intakes showed a modest increased risk of preterm delivery: odds ratios were 1.44 (1.01 to 2.04) for lowest quartile intake of folate and 1.27 (0.95 to 1.69) for lowest quartile intake of folic acid compared with the highest. Findings suggest some evidence that folates influenced risks; however, an interpretation of results was also consistent with no association between intake of folates and preterm delivery.
View details for DOI 10.1055/s-0031-1280855
View details for Web of Science ID 000298200500002
View details for PubMedID 21681695
Phytoestrogens may be associated with a variety of different health outcomes, including outcomes related to reproductive health. Recently published data on phytoestrogen content of a wide range of foods provide an opportunity to improve estimation of dietary phytoestrogen intake.Using the recently published data, we estimated intake among a representative sample of 6,584 women of reproductive age from a multi-site, population-based case-control study, the National Birth Defects Prevention Study (NBDPS). The NBDPS uses a shortened version of the Willett food frequency questionnaire to estimate dietary intake during the year before pregnancy. We estimated intake among NBDPS control mothers.Lignans contributed 65% of total phytoestrogen intake; isoflavones, 29%; and coumestrol, 5%. Top contributors to total phytoestrogen intake were vegetables (31%) and fruit (29%); for isoflavones, dairy (33%) and fruit (21%); for lignans, vegetables (40%) and fruit (29%); and for coumestans, fruit (55%) and dairy (18%). Hispanic women had higher phytoestrogen intake than non-Hispanic white or black women. Associations with maternal age and folic acid-containing supplements were more modest but indicated that older mothers and mothers taking supplements had higher intake.The advantage of the approach used for the current analysis lies in its utilization of phytoestrogen values derived from a single laboratory that used state-of-the-art measurement techniques. The database we developed can be applied directly to other studies using food frequency questionnaires, especially the Willett questionnaire. The database, combined with consistent dietary intake assessment, provides an opportunity to improve our ability to understand potential associations of phytoestrogen intake with health outcomes.
View details for DOI 10.1186/1475-2891-10-105
View details for Web of Science ID 000295960300001
View details for PubMedID 21978267
A recent workshop highlighted the current challenges and new opportunities for studying the role of genetic factors in the etiology of human birth defects. The workshop provided a series of recommendations pertaining to the use of animal models, key elements of population-based designs, the need for national collaborative projects, biorepositories, and consortia, investigation of new types of structural genetic variants, examination of gene-exposure interactions, and a strategy for gene variant discovery. A key reason to hold the recent workshop and contribute this concise communication to the literature is to draw attention to and initiate action toward advancing discoveries about the genetic etiologies of birth defects.
View details for DOI 10.1002/ajmg.a.34103
View details for Web of Science ID 000294088100005
View details for PubMedID 21739590
Congenital heart defects (CHDs) are the most common of all birth defects, yet molecular mechanism(s) underlying highly prevalent atrial septal defects (ASDs) and ventricular septal defects (VSDs) have remained elusive. We demonstrate the indispensability of "balanced" posttranslational small ubiquitin-like modifier (SUMO) conjugation-deconjugation pathway for normal cardiac development. Both hetero- and homozygous SUMO-1 knockout mice exhibited ASDs and VSDs with high mortality rates, which were rescued by cardiac reexpression of the SUMO-1 transgene. Because SUMO-1 was also involved in cleft lip/palate in human patients, the previous findings provided a powerful rationale to question whether SUMO-1 was mutated in infants born with cleft palates and ASDs. Sequence analysis of DNA from newborn screening blood spots revealed a single 16 bp substitution in the SUMO-1 regulatory promoter of a patient displaying both oral-facial clefts and ASDs. Diminished sumoylation activity whether by genetics, environmental toxins, and/or pharmaceuticals may significantly contribute to susceptibility to the induction of congenital heart disease worldwide. Birth Defects Research (Part A) 2011. © 2011 Wiley-Liss, Inc.
View details for DOI 10.1002/bdra.20816
View details for Web of Science ID 000291545100007
View details for PubMedID 21563299
Gastroschisis is increasing in many countries, especially among young women. Because young women may have inadequate nutrition, we assessed the relationship between individual nutrients and the risk for gastroschisis.We analyzed data from the National Birth Defects Prevention Study, a population-based case-control study. Cases were ascertained from 10 birth defect surveillance systems. Controls were randomly selected from birth certificates or hospital records. Nutrient intake was estimated for the year prior to conception from maternal interviews based on a 58-item food frequency questionnaire and cereal consumption reported. A total of 694 cases and 6157 controls were available for analysis.Reported intake of individual nutrients did not substantially affect the risk for gastroschisis. Stratification by maternal age, preconception body mass index, folic acid-containing supplements, or energy intake (kilocalories) did not alter risk estimates.This study does not support an increased risk for gastroschisis with decreasing tertiles of individual nutrients.
View details for DOI 10.1016/j.ajog.2010.12.053
View details for Web of Science ID 000290206200025
View details for PubMedID 21396620
Newborn screening programs store-under varying conditions-residual dried blood spots (DBS). Residual DBS were used to investigate the contribution of congenital infection with Toxoplasma gondii to the etiology of hydrocephalus and as a key step, we assessed the effect of storage conditions on the stability of newborn screening biomarkers.Infants with hydrocephalus (410 cases) were identified using population-based birth defects surveillance systems in California, North Carolina, and Texas. Infants without birth defects (448 controls) were randomly selected from the same geographic areas and time periods. California stores DBS with controlled temperature, while North Carolina and Texas store DBS under ambient conditions. After removal of personal identifiers, DBS were tested for Toxo-specific immunoglobulin-M (Toxo-IgM). Because of poor elution of DBS stored in ambient conditions, additional biomarkers were tested on a specimen subset.Among 858 DBS tested, Toxo-IgM was found in 3 cases and no controls from California (N=515) and in no specimens from North Carolina or Texas (N=343). Among the 98 specimens tested for selected biomarkers, statistically significant differences were found for California vs. combined North Carolina and Texas DBS (thyroid stimulating hormone, phenylalanine, methionine, leucine and citrulline p<0.0001; tyrosine and valine p<0.001).Storage conditions for residual DBS had an effect on the ability to extract, recover, and accurately measure Toxo-IgM and other biomarkers from the filter paper matrix.
View details for DOI 10.1016/j.cca.2010.11.028
View details for Web of Science ID 000286713800009
View details for PubMedID 21114968
To examine the association of craniosynostosis with maternal intake of folic acid-containing supplements and dietary nutrients.The study included deliveries from 1997 to 2005 from the National Birth Defects Prevention Study. Nonsyndromic infants with craniosynostosis (n = 815) were compared to nonmalformed, population-based liveborn control infants (n = 6789), by estimating adjusted odds ratios (AORs) and 95% confidence intervals (CIs) from logistic regression models that included mother's age, parity, race-ethnicity, education, body mass index, smoking, alcohol, fertility treatments, plurality, and study center. We compared quartiles of intake and specified nutrients as continuous.Intake of folic acid-containing supplements was not associated with craniosynostosis (AORs were close to 1). Analyses of dietary nutrients were restricted to mothers who took supplements during the first trimester (i.e., most women). Based on continuous specifications of nutrients, sagittal synostosis risk was significantly lower among women with higher intake of riboflavin and vitamins B?, E, and C; metopic synostosis risk was significantly higher among women with higher intakes of choline and vitamin B??; and coronal synostosis risk was significantly lower among women with higher intake of methionine and vitamin C. As examples, AORs for sagittal synostosis among women with intakes of vitamin B? and riboflavin in the highest versus lowest quartiles were 0.4 (95% CI, 0.2-0.6) and 0.5 (95% CI, 0.3-0.7), respectively.This analysis suggests that dietary intake of certain nutrients may be associated with craniosynostosis, and results may vary by suture type.
View details for DOI 10.1002/bdra.20717
View details for Web of Science ID 000285396200006
View details for PubMedID 20842649
The study objective was to examine the association of microtia with maternal intake of folic-acid-containing supplements and obesity. The study data included deliveries from 1997 to 2005 from the National Birth Defects Prevention Study. Non-syndromic cases of microtia were compared to non-malformed, population-based liveborn control infants, by estimating adjusted odds ratios (AORs) and 95% confidence intervals (CIs) from logistic regression models that included maternal race/ethnicity, education, and study site. Maternal obesity was only weakly associated with microtia. Maternal periconceptional intake of folic-acid-containing vitamin supplements reduced the risk for microtia, but only among non-obese women (OR: 0.63; 95% CI: 0.44-0.91). The reduced risk was stronger when analyses were restricted to isolated cases (OR: 0.51; 95% CI: 0.34-0.77), and it was independent of the level of maternal dietary folate intake. Adjusting for maternal race/ethnicity did not reveal alternative interpretations of this association. This analysis suggests that maternal periconceptional intake of folic-acid-containing supplements may provide protection from microtia for non-obese women.
View details for DOI 10.1002/ajmg.a.33694
View details for Web of Science ID 000284005700013
View details for PubMedID 20949601
Schizencephaly is a malformation of cortical development characterized by gray matter-lined clefts in the cerebral cortex and a range of neurological presentations. In some cases, there are features of septo-optic dysplasia concurrently with schizencephaly. The etiologies of both schizencephaly and septo-optic dysplasia are thought to be heterogeneous, but there is evidence that at least some cases have genetic origin. We hypothesized that these disorders may be caused by mutations in three candidate genes: LHX2, a gene with an important cortical patterning role, and HESX1 and SOX2, genes that have been associated with septo-optic dysplasia. We sequenced a large cohort of patients with schizencephaly, some with features of septo-optic dysplasia, for mutations in these genes. No pathogenic mutations were observed, suggesting that other genes or non-genetic factors influencing genes critical to brain development must be responsible for schizencephaly.
View details for DOI 10.1002/ajmg.a.33684
View details for Web of Science ID 000284005700010
View details for PubMedID 20949537
Folate is a water-soluble B vitamin that must be obtained in the diet or through supplementation. For >50 yr, it has been known that folate plays an integral role in embryonic development. In mice, inactivation of genes in the folate pathway results in malformations of the neural tube, heart, and craniofacial structures. It has been shown that diets and blood levels of women who had a fetus with a neural tube defect are low for several micronutrients, particularly folate. Periconceptional use of folic acid containing supplements decreased recurrent neural tube defects in the offspring of women with a previously affected child and the occurrence of a neural tube defect and possibly other birth defects in the offspring of women with no prior history. Based on these findings, the U.S. Public Health Service recommended that all women at risk take folic acid supplements, but many did not. Mandatory food fortification programs were introduced in numerous countries, including the United States, to improve folate nutritional status and have resulted in a major decrease in neural tube defect prevalence. The success story of folate represents the cooperation of embryologists, experimentalists, epidemiologists, public health scientists, and policymakers.
View details for DOI 10.1096/fj.10-165084
View details for Web of Science ID 000283861100004
View details for PubMedID 20631328
Spina bifida is a malformation of the neural tube and is the most common of neural tube defects (NTDs). The etiology of spina bifida is largely unknown, although it is thought to be multi-factorial, involving multiple interacting genes and environmental factors. Mutations in transcriptional co-activator genes-Cited2, p300, Cbp, Tfap2?, Carm1 and Cart1 result in NTDs in murine models, thus prompt us to investigate whether homologues of these genes are associated with NTDs in humans.Data and biological samples from 297 spina bifida cases and 300 controls were derived from a population-based case-control study conducted in California. 37 SNPs within CITED2, EP300, CREBBP, TFAP2A, CARM1 and ALX1 were genotyped using an ABI SNPlex assay. Odds ratios and 95% confidence intervals were calculated for alleles, genotypes and haplotypes to evaluate the risk for spina bifida.Several SNPs showed increased or decreased risk, including CITED2 rs1131431 (OR = 5.32, 1.04~27.30), EP300 rs4820428 (OR = 1.30, 1.01~1.67), EP300 rs4820429 (OR = 0.50, 0.26~0.50, in whites, OR = 0.7, 0.49~0.99 in all subjects), EP300 rs17002284 (OR = 0.43, 0.22~0.84), TFAP2A rs3798691 (OR = 1.78, 1.13~2.87 in Hispanics), CREBBP rs129986 (OR = 0.27, 0.11~0.69), CARM1 rs17616105 (OR = 0.41, 0.22~0.72 in whites). In addition, one haplotype block in EP300 and one in TFAP2A appeared to be associated with increased risk.Modest associations were observed in CITED2, EP300, CREBBP, TFAP2A and CARM1 but not ALX1. However, these modest associations were not statistically significant after correction for multiple comparisons. Searching for potential functional variants and rare causal mutations is warranted in these genes.
View details for DOI 10.1186/1471-2350-11-141
View details for Web of Science ID 000283360200001
View details for PubMedID 20932315
Obesity is associated with increased risk of many adverse health conditions. During pregnancy, obesity presents particularly important challenges for both mother and baby. Over the last 20 years, studies have emerged indicating an association between prepregnancy weight and risks of birth defects. However, few studies have examined the mechanisms through which this association occurs. Understanding the underlying mechanisms may provide clues to public health strategies for the prevention of birth defects associated with maternal obesity. This article briefly reviews existing literature on the association between maternal obesity and birth defects, discusses potential underlying mechanisms, and suggests research needed to improve our understanding of this important association.
View details for DOI 10.1002/bdra.20679
View details for Web of Science ID 000283638500006
View details for PubMedID 20973050
The goal was to estimate the number of children and adolescents, 0 to 19 years of age, living with spina bifida (SB) in the United States.A retrospective study was conducted by using population-based, birth defect surveillance data from 10 US regions, with vital status ascertainment. Birth defect surveillance data were obtained from Arkansas, Georgia (5 central counties of metropolitan Atlanta), California (11 counties), Colorado, Iowa, New York (New York City excluded), North Carolina, Oklahoma, Texas, and Utah. We estimated the numbers of children 0 to 19 years of age who were living with SB in the 10 US regions in 2002, according to age group, race/ethnicity, and gender, and examined a long-term trend in the prevalence of SB among children 0 to 11 years of age in 1991-2002.The overall prevalence of SB among children and adolescents 0 to 19 years of age in the study regions was 3.1 cases per 10,000 in 2002. The prevalence of SB among children was lower among male and non-Hispanic black children.The prevalence estimates of SB among children and adolescents varied according to region, race/ethnicity, and gender, which suggests possible variations in prevalence at birth and/or inequities in survival rates. Additional studies are warranted to elucidate the reasons for these variations and to derive prevalence estimates of SB among adults.
View details for DOI 10.1542/peds.2009-2084
View details for Web of Science ID 000280565700013
View details for PubMedID 20624803
This study investigated the association of neural tube defects (NTDs) with maternal periconceptional intake of folic acid-containing supplements and dietary nutrients, including folate, among deliveries that occurred after folic acid fortification in selected California counties.The population-based case-control study included fetuses and live born infants with spina bifida (189) or anencephaly (141) and 625 nonmalformed, live born controls delivered from 1999 to 2003. Mothers reported supplement use during telephone interviews, which included a 107-item food frequency questionnaire. For dietary nutrients, intakes <25th, 25th to <75th (reference), and > or =75th percentile were compared, based on control distributions.After adjustment for potential confounders, any versus no supplement intake resulted in ORs of 0.8 (95% CI, 0.5-1.3) for anencephaly and 0.8 (95% CI, 0.6-1.2) for spina bifida. After stratification by maternal intake of vitamin supplements, most factors in the glycemic pathway were not associated with either NTD, with the exception of low levels of fructose and glucose that were significantly associated with anencephaly. Some nutrients that contribute to one-carbon metabolism showed lowered risks (folate, riboflavin, vitamins B(6) and B(12)); others did not (choline, methionine, zinc). Antioxidant nutrients tended to be associated with lowered risks (vitamins C, E, A, beta-carotene, lutein).Mothers' intake of vitamin supplements was modestly if at all associated with a lowered risk of NTDs. Dietary intake of several nutrients contributing to one-carbon metabolism and oxidative stress were associated with reduced NTD risk.
View details for DOI 10.1002/bdra.20675
View details for Web of Science ID 000281529700009
View details for PubMedID 20740594
Environmental contaminants that disrupt endocrine function may contribute to hypospadias etiology.To compare levels of selected halogenated organic pollutants in women delivering infants with and without hypospadias.This study examined levels of nine polybrominated flame retardants (PBDEs), 30 polychlorinated biphenyls (PCBs) and nine persistent pesticides in mid-pregnancy serum samples from 20 women who delivered infants with hypospadias and 28 women who delivered unaffected infants, in California. Analytes were measured using isotope dilution high-resolution mass spectrometry. Values below individual limits of detection (LOD) for each analyte were imputed based on a truncated multivariate normal distribution. Levels of 17 analytes for which at least 50% of cases and controls had values above the LOD were compared using t-tests and by generating odds ratios from logistic regression analyses.Means were greater for cases than controls for 11 of the 17 reported analytes (4 of 5 PBDEs, 7 of 9 PCBs, and 0 of 3 other persistent pesticides), but none of the differences were statistically significant. Eleven of the 17 odds ratios exceeded one (the same analytes that had greater means), but none of the confidence intervals excluded one. After adjustment for sample processing time and foreign-born Hispanic race-ethnicity, only four of the odds ratios exceeded one.Levels of the PBDEs and PCBs were not statistically significantly different, but the sample size was small. The current study adds to a relatively limited knowledge base regarding the potential association of specific contaminants with hypospadias or other birth defects.
View details for DOI 10.1016/j.chemosphere.2010.04.055
View details for Web of Science ID 000280749500005
View details for PubMedID 20494400
Using an Affymetrix GeneChip(R) Human Mapping 100K Set to study a patient with a late-presenting, right-sided diaphragmatic hernia and microphthalmia, we found a maternally inherited deletion that was 2.7 Mb in size at chromosome 18q22.1. Mapping of this deletion using fluorescence in situ hybridization revealed three deleted genes-CDH19, DSEL, and TXNDC10, and one gene that contained the deletion breakpoint, CCDC102B. We selected DSEL for further study in 125 patients with diaphragmatic hernias, as it is involved in the synthesis of decorin, a protein that is required for normal collagen formation and that is upregulated during myogenesis. We found p.Met14Ile in an unrelated patient with a late-presenting, anterior diaphragmatic hernia. In the murine diaphragm, Dsel was only weakly expressed at the time of diaphragm closure and its expression in C2C12 myoblast cells did not change significantly during myoblast differentiation, thus reducing the likelihood that the gene is involved in myogenesis of the diaphragm. Although it is possible that the 18q22.1 deletion and haploinsufficiency for DSEL contributed to the diaphragmatic defect in the patient, a definite role for DSEL and decorin in the formation of the collagen-containing, central tendon of the diaphragm has not yet been established.
View details for DOI 10.1002/ajmg.a.33341
View details for Web of Science ID 000276754000017
View details for PubMedID 20358601
To describe maternal exposure to tobacco in the three months before conception and throughout pregnancy, examine risk factors associated with tobacco exposure in pregnancy and smoking cessation, assess use of pharmacotherapy for smoking cessation and evaluate birth outcomes by smoking status.A cohort of women from a multi-site United States study were asked retrospectively about their exposure to tobacco.The study population was comprised of 4,667 mothers of non-malformed control infants who participated in the National Birth Defects Prevention Study from 1997 to 2003.Using computer-assisted telephone interview responses from this population-based sample, we assessed patterns of maternal smoking and exposure to environmental tobacco smoke (ETS) as well as use of pharmacotherapy for quitting smoking during pregnancy.Overall, 961 (20.6%) mothers reported any smoking and 1,401 (30.0%) reported any exposure to ETS at home or work during the three months before conception through pregnancy. Of the 961 smokers, 512 (53.3%) reportedly quit smoking before or during pregnancy, including 379 (74% of quitters) in the first trimester, and 420 (43.7%) continued to smoke throughout the pregnancy. Only 2.1% of smokers reportedly used pharmacotherapy to quit smoking anytime from three months before conception through pregnancy. Low birthweight and preterm delivery rates were lowest among offspring of non-smokers and highest in offspring of those who continued to smoke throughout pregnancy.About one-half of mothers who reported preconceptional smoking quit before or during pregnancy. Use of pharmacotherapy to quit smoking during pregnancy was not common.
View details for DOI 10.3109/00016341003692261
View details for Web of Science ID 000277094700011
View details for PubMedID 20367429
Fgfrl1 (also known as Fgfr5; OMIM 605830) homozygous null mice have thin, amuscular diaphragms and die at birth because of diaphragm hypoplasia. FGFRL1 is located at 4p16.3, and this chromosome region can be deleted in patients with congenital diaphragmatic hernia (CDH). We examined FGFRL1 as a candidate gene for the diaphragmatic defects associated with 4p16.3 deletions and re-sequenced this gene in 54 patients with CDH. We confirmed six known coding single nucleotide polymorphisms (SNPs): c.209G > A (p.Pro20Pro), c.977G > A (p.Pro276Pro), c.1040T > C (p.Asp297Asp), c.1234C > A (p.Pro362Gln), c.1420G > T (p.Arg424Leu), and c.1540C > T (p.Pro464Leu), but we did not identify any gene mutations. We genotyped additional CDH patients for four of these six SNPs, including the three non-synonymous SNPs, to make a total of 200 chromosomes, and found that the allele frequency for the four SNPs, did not differ significantly between patients and normal controls (p > or = 0.05). We then used Affymetrix Genechip Mouse Gene 1.0 ST arrays and found eight genes with significantly reduced expression levels in the diaphragms of Fgfrl1 homozygous null mice when compared with wildtype mice-Tpm3, Fgfrl1 (p = 0.004), Myl2, Lrtm1, Myh4, Myl3, Myh7 and Hephl1. Lrtm1 is closely related to Slit3, a protein associated with herniation of the central tendon of the diaphragm in mice. The Slit proteins are known to regulate axon branching and cell migration, and inhibition of Slit3 reduces cell motility and decreases the expression of Rac and Cdc42, two genes that are essential for myoblast fusion. Further studies to determine if Lrtm1 has a similar function to Slit3 and if reduced Fgfrl1 expression can cause diaphragm hypoplasia through a mechanism involving decreased myoblast motility and/or myoblast fusion, seem indicated.
View details for DOI 10.1007/s00439-009-0777-8
View details for Web of Science ID 000274456500006
View details for PubMedID 20024584
Few inquiries into periconceptional nutrition, other than folate, and risk of heart defects exist. We investigated the observed association between conotruncal heart defects and periconceptional vitamin use, as well as potential associations with other dietary nutrients.Data derived from a population-based, case-control study of fetuses and liveborn infants among California births between July 1999 and June 2004; 76% of eligible case mothers and 77% of eligible control mothers were interviewed. Cases included 140 with d-transposition of great arteries (dTGA), and 163 with tetralogy of Fallot (TOF). Total number of controls was 698. Use of vitamins was elicited by questionnaire for the periconceptional period. Dietary nutrient intake was elicited by a well-known food frequency questionnaire.The odds ratio for dTGA associated with supplemental vitamin use was 1.0 (95% confidence interval [CI], 0.7-1.5) and for TOF was 0.9 (95% CI, 0.6-1.3). We observed increased risks associated with lower dietary intakes of linoleic acid, total carbohydrate, and fructose for dTGA, whereas decreased risks were observed for lower intakes of total protein and methionine for TOF. Lower dietary intake of several micronutrients-namely folate, niacin, riboflavin, and vitamins B(12), A, and E, even after simultaneous adjustment for other studied nutrients-was associated with increased risk of dTGA but not TOF. These associations were observed among women who did not use vitamin supplements periconceptionally. Analytic consideration of several potential confounders did not reveal alternative interpretations of the results.Evidence continues to accumulate to show that nutrients, particularly folate, influence risks of structural birth defects. Our results extend observations that other nutrients may also be important in heart development.
View details for DOI 10.1002/bdra.20648
View details for Web of Science ID 000276125800002
View details for PubMedID 20063270
Spina bifida, a neural tube closure defect (NTD) involving the posterior portion of what will ultimately give rise to the spinal cord, is one of the most common and serious birth defects. The etiology of spina bifida is thought to be multi-factorial and involve multiple interacting genes and environmental factors. The causes of this congenital malformation remain largely unknown. However, several candidate genes for spina bifida have been identified in lower vertebrates, including the planar cell polarity (PCP) genes. We used data from a case-control study conducted in California to evaluate the association between variation within several key PCP genes and the risk of spina bifida. The PCP genes included in this study were the human homologs of the Xenopus genes Flamingo, Strabismus, Prickle, Dishevelled, and Scrib, two of the homologs of Xenopus Wnt genes, WNT5A and WNT11, and two of the homologs of Xenopus Frizzled, FZD3 and FZD6. None of the 172 SNPs that were evaluated were significantly associated with spina bifida in any racial/ethnic group after correction for multiple testing. However, several SNPs in the PRICKLE2 gene had unadjusted P-value <0.01. In conclusion, our results, though largely negative, suggest that the PRICKLE2 gene may potentially modify the risk of spina bifida and deserves further investigation.
View details for DOI 10.1002/ajmg.a.33230
View details for Web of Science ID 000274508300005
View details for PubMedID 20101694
Non-syndromic craniosynostosis is multifactorial, and fetal head constraint has been hypothesized as one factor thought to play a role. Data from the National Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of birth defects, were used to evaluate associations between four selected factors related to fetal constraint and craniosynostosis: plurality (twins or higher), macrosomia (birth weight >4,000 g), post-term gestational age (> or =42 weeks), and nulliparity (no previous live births). Case infants (n = 675) had craniosynostosis documented either by radiographic evidence or by surgical intervention. Infants with a recognized or strongly suspected single-gene conditions or chromosomal abnormalities were excluded. Control infants (n = 5,958) had no major birth defects and were randomly selected from the same population as case infants. Logistic regression was used to estimate odds ratios for the association between these four factors and craniosynostosis, while adjusting for several covariates. We found that plurality and nulliparity were associated with a twofold increased risk for metopic craniosynostosis, and macrosomia had almost twice the risk of developing coronal craniosynostosis. Contrary to our hypothesis, prematurity and low birth weight were also associated with craniosynostosis. In conclusion, these four constraint-related factors were not found to be associated with craniosynostosis when all suture types were combined, though some types of craniosynostosis were associated with individual constraint-related factors.
View details for DOI 10.1002/ajmg.a.33246
View details for Web of Science ID 000274508300019
View details for PubMedID 20101684
Clark (1996) proposed that abnormal blood flow is related to some congenital cardiovascular malformations (CCVMs), particularly CCVM with obstruction to blood flow. Our hypothesis is that CCVMs may relate to genes that affect blood coagulation or flow. We studied whether polymorphisms of such genes are related to CCVMs; previous association of these SNPs to conotruncal CCVMs is described.We assessed risk of pulmonary stenosis (PS, N = 120), atrial septal defect (ASD, N = 108), aortic stenosis (AS, N = 36), and coarctation of the aorta (CoAo, N = 64), associated with 33 candidate genes, selected for their relationship to blood flow affected by homocysteine metabolism, coagulation, cell-cell interaction, inflammation, or blood pressure regulation.Effects were specific to cardiac phenotype and race. CoAo was associated with MTHFR (-667) C>T (odds ratio [OR] for TT 3.5, 95% confidence limits [CI] 1.4-8.6). AS was associated with a polymorphism of SERPINE1, G5>G4, OR = 5.6 for the homozygote with 95% CI 1.4-22.9. Unique polymorphisms were associated with increased risk of ASD and PS: NPPA 664G>A with ASD (OR of 2.4, 95%CI 1.3-4.4) and NOS3 (-690) C>T with PS (OR 6.1; 95% CI 1.6-22.6 in the African American population only). For ASD, the NPPA (-664) G>A SNP there was increased risk from the variant genotype only in maternal smokers (OR 2.6; 95% CI 1.0-7.2).Genes affecting vascular function and coagulation appear to be promising candidates for the etiology of cardiac malformations and warrant further study.
View details for DOI 10.1002/bdra.20630
View details for Web of Science ID 000275389800005
View details for PubMedID 19764075
We sought to determine if there is a relationship between serum concentrations of cytokines and the development of preterm labor. A panel of 28 cytokines was measured using the multiplex assay in serum samples collected between 15 and 18 weeks' gestation from women who developed spontaneous preterm labor and delivered between 24 and 28 weeks' gestation (N = 25) and from women who delivered at term (>or=37 weeks; N = 25). Sixteen of the 28 cytokines measured were detected. Except for vascular endothelial growth factor, which showed a trend toward a significant increase in patients who developed preterm labor, there was no difference in cytokine levels between groups in preterm labor and in term labor. Serum cytokine changes in women who develop spontaneous preterm labor possibly occur in the period between 18 weeks' gestation and the onset of labor.
View details for DOI 10.1055/s-0029-1234037
View details for Web of Science ID 000273825200006
View details for PubMedID 19644787
Evidence exists for an association between use of vitamin supplements with folic acid in early pregnancy and reduced risk for offspring with cleft lip with/without cleft palate (CLP). A few observations have been made about nutrients related to one-carbon metabolism other than folate. Our prospective study attempted to extend information on nutrition and CLP by measuring nutrient analytes in mid-pregnancy sera. This study included data from a repository of women's mid-pregnancy serum specimens collected in California from 2003-04. Each woman's specimen was linked with delivery information to determine whether her fetus had CLP or another structural malformation, or was nonmalformed. We identified 89 CLP cases. We randomly selected 409 specimens as controls. Specimens were tested for homocysteine, methylmalonic acid, folate, vitamin B12, pyridoxal phosphate, pyridoxal, pyridoxic acid, riboflavin, choline, betaine, methionine, methionine sulfoxide, cysteine, cystathionine, arginine, and asymmetric and symmetric dimethylarginine. We observed three analytes with odds ratios unlikely to be explained by random variation, i.e., elevated CLP risks were observed for low levels and for high levels of pyridoxal phosphate (vitamin B6), higher levels of choline, and low levels of symmetric dimethylarginine. These data did not show meaningful differences between cases and controls for any other analytes.
View details for Web of Science ID 000271039100003
View details for PubMedID 19668105
To evaluate the representativeness of controls in an ongoing, population-based, case-control study of birth defects in 10 centers across the United States, researchers compared 1997-2003 birth certificate data linked to selected controls (n = 6,681) and control participants (n = 4,395) with those from their base populations (n = 2,468,697). Researchers analyzed differences in population characteristics (e.g., percentage of births at > or =2,500 g) for each group. Compared with their base populations, control participants did not differ in distributions of maternal or paternal age, previous livebirths, maternal smoking, or diabetes, but they did differ in other maternal (i.e., race/ethnicity, education, entry into prenatal care) and infant (i.e., birth weight, gestational age, and plurality) characteristics. Differences in distributions of maternal, but not infant, characteristics were associated with participation by selected controls. Absolute differences in infant characteristics for the base population versus control participants were < or =1.3 percentage points. Differences in infant characteristics were greater at centers that selected controls from hospitals compared with centers that selected controls from electronic birth certificates. These findings suggest that control participants in the National Birth Defects Prevention Study generally are representative of their base populations. Hospital-based control selection may slightly underascertain infants affected by certain adverse birth outcomes.
View details for DOI 10.1093/aje/kwp226
View details for Web of Science ID 000270445300007
View details for PubMedID 19736223
To examine the association of multiple measures of socioeconomic status (SES) with risks of orofacial clefts and conotruncal heart defects.Data were from a recent population-based case-control study conducted in California that included 608 patients with orofacial clefts, 277 patients with conotruncal heart defects, and 617 nonmalformed controls.The odds ratio for the worst versus best score on a household-level SES index was strongest for cleft lip with or without palate, at 1.7 (95% confidence interval, 0.9-3.4); the odds ratios for this comparison were closer to 1 and less precise for the other defect groups. An index based on neighborhood-level SES was also not associated with increased risk of the studied defects.This detailed analysis of SES and selected birth defects did not suggest worse SES was associated with increased risk of the studied defects, with the possible exception of cleft lip with or without cleft palate.
View details for DOI 10.1002/bdra.20614
View details for Web of Science ID 000271348700006
View details for PubMedID 19645048
Folic acid is known to reduce risk of neural tube defects (NTDs). Even so, NTDs continue to occur despite individual supplementation or population fortification with folic acid. We investigated other nutrients related to one-carbon metabolism that may affect NTD risk.This prospective study included data from more than 180,000 pregnant women in California from 2003 through 2005. Midpregnancy serum specimens were linked with delivery information regarding the presence of a NTD, another structural malformation, or no malformation in the fetus. We identified 80 NTD-affected pregnancies (cases) and we randomly selected 409 pregnancy controls. Serum specimens were tested for methylmalonic acid, homocysteine, cysteine, methionine, total choline, betaine, cystathionine, vitamin B6, folate, vitamin B12, riboflavin, and creatinine.We observed elevated NTD risks associated with lower levels of total choline, and reduced risks with higher levels of choline. Specifically, we observed an odds ratio of 2.4 (95% confidence interval = 1.3-4.7) associated with the lowest decile and an odds ratio of 0.14 (0.02-1.0) associated with the highest decile, both relative to the 25th-74th percentiles of the control distribution. These data did not show meaningful differences between cases and controls for any other analytes.This is the first study to investigate total choline in NTD-affected pregnancies. Our findings for choline, for which low levels were a risk factor and higher levels were a protective factor for NTDs, may offer a useful clue toward understanding the complex etiologies of NTDs in an era of folic acid fortification of the food supply.
View details for DOI 10.1097/EDE.0b013e3181ac9fe7
View details for Web of Science ID 000269103500017
View details for PubMedID 19593156
The association between periconceptional intake of supplements containing folic acid with specific subtypes of limb deficiencies has been inconsistent. The objective was to investigate whether intake of nutrients involved in one-carbon metabolism (folate, vitamin B(6), vitamin B(12), riboflavin, choline, betaine, zinc, and methionine) through diet alone or in combination with a supplement containing folic acid influenced the risk for transverse limb deficiency (TLD) and longitudinal limb deficiency (LLD).We analyzed 1997-2003 data from the National Birth Defects Prevention Study and included 324 case infants with TLD, 158 case infants with LLD, and 4982 nonmalformed control infants. A food frequency questionnaire was used to estimate nutrient intakes. Use of supplements containing folic acid 1 month before through 2 months after conception was recorded.Use of a supplement containing folic acid was not associated with LLD or TLD. For nonsupplement users, within (1) the lowest quartile of dietary folate intake or vitamin B(6) intake, adjusted odds ratios (aORs) for LLD were, respectively, 3.86 (95% confidence interval [CI]: 1.08-13.78) and 4.36 (95% CI: 0.93-20.48); and (2) the lowest quartile for riboflavin intake, the aOR for TLD was 2.94 (95% CI: 1.04-8.32). For supplement users within the lowest quartile of folate intake or riboflavin intake, the aORs for TLD were, respectively, 1.52 (95% CI: 0.91-2.54) and 1.54 (95% CI: 1.00-2.37).TLD and LLD were not associated with supplement use, but TLD was associated with low intakes of riboflavin from diet.
View details for DOI 10.1002/bdra.20587
View details for Web of Science ID 000270586400004
View details for PubMedID 19350655
Neonatal blood, obtained from a heel stick and stored dry on paper cards, has been the standard for birth defects screening for 50 years. Such dried blood samples are used, primarily, for analysis of small-molecule analytes. More recently, the DNA complement of such dried blood cards has been used for targeted genetic testing, such as for single nucleotide polymorphism in cystic fibrosis. Expansion of such testing to include polygenic traits, and perhaps whole genome scanning, has been discussed as a formal possibility. However, until now the amount of DNA that might be obtained from such dried blood cards has been limiting, due to inefficient DNA recovery technology.A new technology is employed for efficient DNA release from a standard neonatal blood card. Using standard Guthrie cards, stored an average of ten years post-collection, about 1/40th of the air-dried neonatal blood specimen (two 3 mm punches) was processed to obtain DNA that was sufficient in mass and quality for direct use in microarray-based whole genome scanning. Using that same DNA release technology, it is also shown that approximately 1/250th of the original purified DNA (about 1 ng) could be subjected to whole genome amplification, thus yielding an additional microgram of amplified DNA product. That amplified DNA product was then used in microarray analysis and yielded statistical concordance of 99% or greater to the primary, unamplified DNA sample.Together, these data suggest that DNA obtained from less than 10% of a standard neonatal blood specimen, stored dry for several years on a Guthrie card, can support a program of genome-wide neonatal genetic testing.
View details for DOI 10.1186/1471-2156-10-38
View details for Web of Science ID 000269503400001
View details for PubMedID 19624846
To explore whether women who reported corticosteroid use during pregnancy were more likely to deliver an infant with hypospadias than women who did not.The analysis encompassed data on deliveries with an estimated due date between 1997 and 2004 from the National Birth Defects Prevention Study, a large population-based, case-control study conducted in the United States. Included were 1165 cases of moderate to severe hypospadias and 3000 nonmalformed male controls.The mothers of 39 cases (3.3%) and 62 controls (2.1%) reported using a corticosteroid medication during the period extending from 4 weeks before conception to 14 weeks after conception. The odds ratio (OR) for any corticosteroid exposure versus no corticosteroid exposure was 1.6 (95% confidence interval [CI] = 1.1 to 2.5); after adjustment for maternal race/ethnicity, education, age, and study site, it was 1.3 (95% CI = 0.8 to 2.0). Analyses by route of administration and specific component suggest that elevated ORs occurred only for nasal spray/inhaled corticosteroids (OR = 1.5; 95% CI = 0.9 to 2.6).Maternal use of corticosteroid medications was weakly associated with risk of hypospadias, but the association was negligible after adjustment for potential confounders.
View details for DOI 10.1016/j.jpeds.2009.01.039
View details for Web of Science ID 000267672600013
View details for PubMedID 19394038
We used data from the multisite National Birth Defects Prevention Study for expected delivery dates from October 1997 through 2003, to determine whether the increased risk in anencephaly and spina bifida (neural tube defects (NTDs)) in Hispanics was explained by selected sociodemographic, acculturation, and other maternal characteristics.For each type of defect, we examined the association with selected maternal characteristics stratified by race/ethnicity and the association with Hispanic parents' acculturation level, relative to non-Hispanic whites. We used logistic regression and calculated crude odds ratios (ORs) and their 95% confidence intervals (CIs).Hispanic mothers who reported the highest level of income were 80% less likely to deliver babies with spina bifida. In addition, highly educated Hispanic and white mothers had 76 and 35% lower risk, respectively. Other factors showing differing effects for spina bifida in Hispanics included maternal age, parity, and gestational diabetes. For spina bifida there was no significant elevated risk for U.S.-born Hispanics, relative to whites, but for anencephaly, corresponding ORs ranged from 1.9 to 2.3. The highest risk for spina bifida was observed for recent Hispanic immigrant parents from Mexico or Central America residing in the United States <5 years (OR = 3.28, 95% CI = 1.46-7.37).Less acculturated Hispanic parents seemed to be at highest risk of NTDs. For anencephaly, U.S.-born and English-speaking Hispanic parents were also at increased risk. Finally, from an etiologic standpoint, spina bifida and anencephaly appeared to be etiologically heterogeneous from these analyses.
View details for DOI 10.1002/bdra.20582
View details for Web of Science ID 000268426000007
View details for PubMedID 19334286
Folic acid taken in early pregnancy reduces risks for delivering offspring with several congenital anomalies. The mechanism by which folic acid reduces risk is unknown. Investigations into genetic variation that influences transport and metabolism of folate will help fill this data gap. We focused on 118 SNPs involved in folate transport and metabolism.Using data from a California population-based registry, we investigated whether risks of spina bifida or conotruncal heart defects were influenced by 118 single nucleotide polymorphisms (SNPs) associated with the complex folate pathway. This case-control study included 259 infants with spina bifida and a random sample of 359 nonmalformed control infants born during 1983-86 or 1994-95. It also included 214 infants with conotruncal heart defects born during 1983-86. Infant genotyping was performed blinded to case or control status using a designed SNPlex assay. We examined single SNP effects for each of the 118 SNPs, as well as haplotypes, for each of the two outcomes.Few odds ratios (ORs) revealed sizable departures from 1.0. With respect to spina bifida, we observed ORs with 95% confidence intervals that did not include 1.0 for the following SNPs (heterozygous or homozygous) relative to the reference genotype: BHMT (rs3733890) OR = 1.8 (1.1-3.1), CBS (rs2851391) OR = 2.0 (1.2-3.1); CBS (rs234713) OR = 2.9 (1.3-6.7); MTHFD1 (rs2236224) OR = 1.7 (1.1-2.7); MTHFD1 (hcv11462908) OR = 0.2 (0-0.9); MTHFD2 (rs702465) OR = 0.6 (0.4-0.9); MTHFD2 (rs7571842) OR = 0.6 (0.4-0.9); MTHFR (rs1801133) OR = 2.0 (1.2-3.1); MTRR (rs162036) OR = 3.0 (1.5-5.9); MTRR (rs10380) OR = 3.4 (1.6-7.1); MTRR (rs1801394) OR = 0.7 (0.5-0.9); MTRR (rs9332) OR = 2.7 (1.3-5.3); TYMS (rs2847149) OR = 2.2 (1.4-3.5); TYMS (rs1001761) OR = 2.4 (1.5-3.8); and TYMS (rs502396) OR = 2.1 (1.3-3.3). However, multiple SNPs observed for a given gene showed evidence of linkage disequilibrium indicating that the observed SNPs were not individually contributing to risk. We did not observe any ORs with confidence intervals that did not include 1.0 for any of the studied SNPs with conotruncal heart defects. Haplotype reconstruction showed statistical evidence of nonrandom associations with TYMS, MTHFR, BHMT and MTR for spina bifida.Our observations do not implicate a particular folate transport or metabolism gene to be strongly associated with risks for spina bifida or conotruncal defects.
View details for DOI 10.1186/1471-2350-10-49
View details for Web of Science ID 000267862600001
View details for PubMedID 19493349
Orofacial clefts are among the most common types of birth defects, but their clinical presentation has not been well described in a geographically diverse US population. To describe the birth prevalence and phenotype of nonsyndromic clefts, we used data from the National Birth Defects Prevention Study (NBDPS), a multi-site, population-based, case-control study aimed at identifying genetic and environmental risk factors for birth defects. Included in the study were infants born during 1997-2004 with a cleft lip (CL), cleft lip with cleft palate (CLP), or cleft palate (CP). Infants with clefts associated with recognized single-gene disorders, chromosome abnormalities, holoprosencephaly, or amniotic band sequence were excluded. A total of 3,344 infants with nonsyndromic orofacial clefts were identified, including 751 with CL, 1,399 with CLP, and 1,194 with CP, giving birth prevalence estimates of 0.3, 0.5, and 0.4/1,000 live births, respectively. Among infants with CLP where cleft laterality was specified, about twice as many had unilateral vs. bilateral involvement, while for CL there were over 10 times as many with unilateral versus bilateral involvement. Involvement was most often left-sided. About one-quarter of infants with CP had Pierre Robin sequence. Over 80% of infants had an isolated orofacial cleft. Among infants with CL or CLP, heart, limb, and other musculoskeletal defects were most commonly observed, while heart, limb, and central nervous system defects were most common among infants with CP. Better understanding of the birth prevalence and phenotype may help guide clinical care as well as contribute to an improved understanding of pathogenesis.
View details for DOI 10.1002/ajmg.a.32854
View details for Web of Science ID 000266684200006
View details for PubMedID 19441124
This study compared the prevalence of cardiovascular defects in twin and singleton births and explored the influences of zygosity (monozygotic and dizygotic) and maternal age (<35 and >or=35 years of age) on concordance. Data on twin and singleton infants with (n = 628 twin pairs and n = 14,078 singletons) and without (n = 53,974 twin pairs and n = 4,858,255 singletons) cardiovascular defects were obtained from the California Birth Defects Monitoring Program and the California vital statistics birth and fetal death records during the period 1983-2003. Prevalence ratios (PR) (prevalence of twin/singleton) and approximate 95% confidence intervals were calculated for 16 congenital cardiovascular categories. Poisson regression techniques using log-linear models were employed to assess whether the probability of concordance of defects within each cardiovascular category varied by zygosity or maternal age. An increased prevalence was observed in twins compared to singletons in all 16 cardiovascular categories. Seven of the cardiovascular categories had at least double the prevalence in twins compared to singletons. Like-sex twins, as a proxy of monozygosity, had an increased prevalence of cardiovascular defects compared to unlike sex twins. Probabilities of concordance for flow lesions were higher among monozygotic than dizygotic twins. Our study provides evidence that twinning is associated with more cardiovascular defects than singletons. Increased concordance for flow lesions in monozygotic twins was observed, an observation that is in agreement with findings from familial recurrence studies of cardiovascular defects.
View details for DOI 10.1002/ajmg.a.32745
View details for Web of Science ID 000265805900010
View details for PubMedID 19353581
Congenital diaphragmatic hernia (CDH) is a common birth defect for which few causative genes have been identified. Several candidate regions containing genes necessary for normal diaphragm development have been identified, including a 4-5 Mb deleted region at chromosome 1q41-1q42 from which the causative gene(s) has/have not been cloned. We selected the HLX gene from this interval as a candidate gene for CDH, as the Hlx homozygous null mouse has been reported to have diaphragmatic defects and the gene was described as being expressed in the murine diaphragm. We re-sequenced HLX in 119 CDH patients and identified four novel single nucleotide substitutions that predict amino acid changes: p.S12F, p.S18L, p.D173Y and p.A235V. These sequence alterations were all present in patients with isolated CDH, although patients with both isolated CHD and CDH with additional anomalies were studied. The single-nucleotide substitutions were absent in more than 186 control chromosomes. In-situ hybridization studies confirmed expression of Hlx in the developing murine diaphragm at the site of the junction of the diaphragm and the liver. Although functional studies to determine if these novel sequence variants altered the inductive activity of Hlx on the alpha-smooth muscle actin and SM22alpha promoters showed no significant differences between the variants and wild-type Hlx, sequence variants in HLX may still be relevant in the pathogenesis of CDH in combination with additional genetic and environmental factors.
View details for DOI 10.1111/j.1399-0004.2009.01182.x
View details for Web of Science ID 000265708200005
View details for PubMedID 19459883
Several studies have reported that neural tube defects (NTD) occur more frequently among children born to women of lower socio-economic status (SES). This study investigated the relationship between individual- and neighbourhood-level SES and the risk of an NTD-affected pregnancy. Data were drawn from a population-based case-control study of fetuses and infants among a cohort of California births between July 1999 and June 2003. Information on individual SES was obtained via telephone interviews with mothers of 337 (76% of eligible) cases and 626 (79% of eligible) non-malformed liveborn controls. Respondents' addresses were linked to the 2000 US Census to characterise six measures of neighbourhood SES (education, poverty, unemployment, occupation, crowding and rental occupancy). The analyses indicated that relative to women with a high school education, those with less than a high school education had a 1.7-fold increased risk of delivering infants with NTDs [95% CI 1.2, 2.6]. Twofold elevated risks for NTDs were observed for women with less than a high school education who lived in neighbourhoods where a majority of residents had not graduated from high school [95% CI 1.3, 3.1]. No consistent risk gradients were observed between NTD-affected pregnancies and indicators of lower neighbourhood SES. Results for phenotype subgroups were similar to those for all cases. Low maternal education was associated with an elevated risk of NTD in offspring. This risk varied by the education profile of the neighbourhood: women who did not graduate from high school and lived in less educated neighbourhoods exhibited a higher risk.
View details for DOI 10.1111/j.1365-3016.2008.00992.x
View details for Web of Science ID 000262645600003
View details for PubMedID 19159398
This study examines the probability of twins by birth year, maternal race-ethnicity, age, and parity and the influences of these demographic factors on the probability of male in twins and singletons in a large, racially diverse population. Recent publications note steep increases in twin births while the probability of male births has been reported to vary by parental race-ethnicity and age and birth order. Probability of male stratified by plurality has not been investigated in California prior to this study. Cubic spline estimates and Poisson regression techniques were employed to describe trends in twins and males using California vital statistics birth and fetal death records over the period from 1983-2003. This study includes 127,787 twin pair and 11,025,106 singleton births. The probability of twins varied by birth year, maternal race-ethnicity, age, and parity. The probability of twins increased by 10.1% from 1983-1992 and increased by 20.1% from 1993-2003, nearly doubling the previous increase. All maternal race-ethnicity groups showed increases in probability of twins with increasing maternal age. Parous women compared to nulliparous women had larger increases in the probability of twins. The probability of males in twins decreased from 1983-1992 and increased from 1993-2003; while in singletons the probability appeared unchanged. These findings show increases in the probability of twins in California from 1983-2003 and identify maternal age, race-ethnicity, and parity groups most likely to conceive twins. The cause of the increase in twins is unknown but coincides with trends towards delayed childbearing and increased use of subfertility treatments.
View details for Web of Science ID 000263635000011
View details for PubMedID 19210184
This study presents a general model of two binary variables and applies it to twin sex pairing data from 21 twin data sources to estimate the frequency of dizygotic twins. The purpose of this study is to clarify the relationship between maximum likelihood and Weinberg's differential rule zygosity estimation methods. We explore the accuracy of these zygosity estimation measures in relation to twin ascertainment methods and the probability of a male. Twin sex pairing data from 21 twin data sources representing 15 countries was collected for use in this study. Maximum likelihood estimation of the probability of dizygotic twins is applied to describe the variation in the frequency of dizygotic twin births. The differences between maximum likelihood and Weinberg's differential rule zygosity estimation methods are presented as a function of twin data ascertainment method and the probability of a male. Maximum likelihood estimation of the probability of dizygotic twins ranges from 0.083 (95% approximate CI: 0.082, 0.085) to 0.750 (95% approximate CI: 0.749, 0.752) for voluntary ascertainment data sources and from 0.374 (95% approximate CI: 0.373, 0.375) to 0.987 (95% approximate CI: 0.959, 1.016) for active ascertainment data sources. In 17 of the 21 twin data sources differences of 0.01 or less occur between maximum likelihood and Weinberg zygosity estimation methods. The Weinberg and maximum likelihood estimates are negligibly different in most applications. Using the above general maximum likelihood estimate, the probability of a dizygotic twin is subject to substantial variation that is largely a function of twin data ascertainment method.
View details for Web of Science ID 000263635000009
View details for PubMedID 19210182
TXN2 encodes human thioredoxin 2, a small redox protein important in cellular antioxidant defenses, as well as in the regulation of apoptosis. Txn2 knockout mice fail to complete neural tube closure by E10.5 and die in utero. We hypothesized that genetic variation in human TXN2 gene may alter the function of the encoded protein in a manner associated with an increased risk for neural tube defects (NTDs). A DNA re-sequencing effort of the human TXN2 gene was taken. After a variation in the promoter was identified, the transcriptional activity of different alleles was investigated. The possible association between these variations and the risk of spina bifida was further evaluated in a subset of samples obtained from a large population-based case-control study in California in two different ethnicity groups, non-Hispanic white and Hispanic white. We identified a novel promoter insertion polymorphism located 9 base pairs upstream of the transcription start site of exon 1(-9 insertion). The GA, G and GGGA insertions were associated with a marked decrease of transcriptional activity when overexpressed in both U2-OS (an osteosarcoma cell line) and 293 cells (derived from human embryonic kidney). Further analysis revealed that the GA insertion was associated with increased spina bifida risk for Hispanic whites. Our study revealed a novel Ins/Del polymorphism in the human TXN2 gene proximal promoter region that altered the transcriptional activity and is associated with spina bifida risk. This polymorphism may be a genetic modifier of spina bifida risk in this California population.
View details for DOI 10.1002/ajmg.a.32589
View details for Web of Science ID 000263433400005
View details for PubMedID 19165900
Rates of neural tube defects have decreased since folic acid fortification of the food supply in the United States. The authors' objective was to evaluate the associations between neural tube defects and maternal folic acid intake among pregnancies conceived after fortification. This is a multicenter, case-control study that uses data from the National Birth Defects Prevention Study, 1998-2003. Logistic regression was used to compute crude and adjusted odds ratios between cases and controls assessing maternal periconceptional use of folic acid and intake of dietary folic acid. Among 180 anencephalic cases, 385 spina bifida cases, and 3, 963 controls, 21.1%, 25.2%, and 26.1%, respectively, reported periconceptional use of folic acid supplements. Periconceptional supplement use did not reduce the risk of having a pregnancy affected by a neural tube defect. Maternal intake of dietary folate was not significantly associated with neural tube defects. In this study conducted among pregnancies conceived after mandatory folic acid fortification, the authors found little evidence of an association between neural tube defects and maternal folic acid intake. A possible explanation is that folic acid fortification reduced the occurrence of folic acid-sensitive neural tube defects. Further investigation is warranted to possibly identify women who remain at increased risk of preventable neural tube defects.
View details for DOI 10.1093/aje/kwn331
View details for Web of Science ID 000262152200002
View details for PubMedID 18953063
Conotruncal heart defects compose 25% to 30% of nonsyndromic congenital heart defects. This study describes the frequency of chromosome abnormalities and microdeletion of 22q11 associated among infants and fetuses delivered with conotruncal heart malformations.From a population base of 974,579 infants/fetuses delivered, 622 California infants/fetuses were ascertained with a defect of aortopulmonary septation. Infants whose primary cardiac defect was tetralogy of Fallot (n = 296) or d-transposition of the great arteries (n = 189) were screened for microdeletion of 22q11.Of the infants who had routine karyotypes, 5% had chromosomal abnormalities, including four with extra sex chromosomes. Thirty infants had chromosome 22q11 microdeletions, providing a cause for 10% of infants whose primary defect was tetralogy of Fallot. Right aortic arch, abnormal branching patterns of the major arteries arising from the thoracic aorta, and pulmonary artery abnormalities were observed more frequently among infants with tetralogy of Fallot caused by 22q11 microdeletion.We found an unusual number of infants with an extra sex chromosome and a conotruncal defect. Infants with tetralogy of Fallot owing to 22q11 microdeletion showed more associated vascular anomalies than infants with tetralogy without a 22q11 microdeletion. Although these associated vascular anomalies provide clues as to which infants with tetralogy of Fallot are more likely to carry the microdeletion, the overall risk of 10% among infants with tetralogy of Fallot warrants chromosome analysis and fluorescent in situ hybridization (FISH) testing routinely, which may be supplanted by genome-wide copy number testing as it becomes more widely utilized.
View details for DOI 10.1002/bdra.20541
View details for Web of Science ID 000262904800005
View details for PubMedID 19067405
We examined whether hypospadias is associated with maternal intake of folic acid containing vitamin/mineral supplements or dietary intake of nutrients related to one-carbon metabolism (folate, choline, vitamins B12 and B6, thiamine, riboflavin, methionine and zinc).The study included births from October 1997 to December 2003 that were part of the National Birth Defects Prevention Study. Diet was assessed by food frequency questionnaire during maternal telephone interviews. Analyses included 915 cases with second or third degree hypospadias (urethra opened at the penile shaft, scrotum or perineum) and 2,266 male, liveborn, nonmalformed controls. All ORs and 95% CIs were estimated from logistic regression models that included several potential confounders. Nutrient based analyses also included energy intake.Hypospadias risk was not associated with supplement use (adjusted ORs were 1.2, 95% CI 0.9-1.6 for intake beginning in the month before or the first month of pregnancy and 1.1, 95% CI 0.8-1.4 for intake beginning in the second or third month, relative to no intake). Among women who took supplements reduced hypospadias risk was associated with higher dietary intakes of choline, methionine and vitamin B12. The respective ORs (CIs) for the highest vs lowest quartiles were 0.7 (0.5-1.1), 0.6 (0.4-0.9) and 0.7 (0.5-1.0). Among women who did not take supplements increased risk of hypospadias was associated with higher vitamin B12 intake. The OR (CI) for the highest vs lowest quartile was 3.1 (1.1-9.0).This study suggests an association of hypospadias with intake of certain nutrients related to one-carbon metabolism.
View details for DOI 10.1016/j.juro.2008.09.041
View details for Web of Science ID 000261705900175
View details for PubMedID 19013591
We used conventional and hierarchical logistic regression to examine the association of neural tube defects (NTDs) with intake of 26 nutrients that contribute to the mechanistic pathways of methylation, glycemic control, and oxidative stress, all of which have been implicated in NTD etiology. The hierarchical approach produces more plausible, more stable estimates than the conventional approach, while adjusting for potential confounding by other nutrients.Analyses included 386 cases and 408 nonmalformed controls with complete data on nutrients and potential confounders (race/ethnicity, education, obesity, and intake of vitamin supplements) from a population-based case-control study of deliveries in California from 1989 to 1991. Nutrients were specified as continuous, and their units were standardized to have a mean of zero and standard deviation (SD) of 1 for comparability of units across pathways. ORs reflect a 1-SD increase in the corresponding nutrient.Among women who took vitamin supplements, semi-Bayesian hierarchical modeling results suggested no associations between nutrient intake and NTDs. Among women who did not take supplements, both conventional and hierarchical models (HM) suggested an inverse association between lutein intake and NTD risk (HM odds ratio [OR] = 0.6; 95% confidence interval = 0.5-0.9) and a positive association with sucrose (HM OR 1.4; 1.1-1.8) and glycemic index (HM OR 1.3; 1.0-1.6).Our findings for lutein, glycemic index, and sucrose suggest that further study of NTDs and the glycemic control and oxidative stress pathways is warranted.
View details for DOI 10.1097/EDE.0b013e31818f6375
View details for Web of Science ID 000261930800013
View details for PubMedID 19234400
Past studies of cigarette smoking as a contributor to orofacial clefts and neural tube defects (NTDs) used self-reports of smoke exposures. We have correlated measurements of cotinine (a nicotine metabolite) in mid-pregnancy sera with clefts and NTDs.From a repository of >180 000 mid-pregnancy serum specimens collected in California from 2003 to 2005 and linked to delivery outcome information, we identified 89 orofacial cleft-associated pregnancies, 80 NTD-affected pregnancies, and randomly selected 409 pregnancy specimens that corresponded to infants without malformations as control subjects. Cotinine was measured by liquid chromatography-mass spectrometry. No smoke exposure was defined as cotinine values <2 ng/mL, and any exposure was defined as >or=2 ng/mL.We observed odds ratios of 2.1 (95% CI, 1.0-4.4) for clefts and 0.4 (95% CI, 0.1-1.7) for NTDs associated with exposure. After adjusting for race/ethnicity, age, and serum folate levels, odds ratios were 2.4 (95% CI, 1.1-5.3) and 0.6 (95% CI, 0.1-2.5). We explored 2 cotinine levels, 2 to 10 ng/mL and >10 ng/mL for clefts (data were too sparse for NTDs). Odds ratios for these levels were 3.3 (95% CI, 0.9-11.9) and 1.7 (95% CI, 0.7-4.2), respectively.Smoking exposures, as measured with cotinine levels during mid-pregnancy, were associated with increased risks of clefts and possibly reduced risks of NTDs.
View details for DOI 10.1016/j.jpeds.2008.08.006
View details for Web of Science ID 000262272500006
View details for PubMedID 18990410
Cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO) are common congenital malformations. Numerous epidemiologic studies have shown an increased risk for orofacial clefts among children whose mothers smoked during early pregnancy; however, there is concern that the results of these studies may have been biased because of exposure misclassification. The purpose of this study is to use previous research on the reliability of self-reported cigarette smoking to produce corrected point estimates (and associated credible intervals) of the effect of maternal smoking on children's risk of clefts.We accounted for misclassification using 4 Bayesian models that made different assumptions about the sensitivity and specificity of self-reported maternal smoking data. We used results from previous studies to specify the prior distributions for sensitivity and specificity of reporting and used Markov chain Monte Carlo algorithms to calculate the posterior distribution of the effect of maternal smoking on children's risk for CL/P and CPO.After correcting for potential sources of misclassification in data from the National Birth Defects Prevention Study, we found an increased risk of CL/P among children born to mothers who smoked during early pregnancy (posterior odds ratio [OR] = 1.6, 95% credible interval = 1.1-2.2). The posterior effect of smoking on CPO provided less evidence of effect (posterior OR = 1.1, 95% credible interval = 0.7-1.7).Our results lend some credibility to the hypothesis that periconceptional maternal smoking increases the risk of a child being born with CL/P. The results concerning CPO provide no overall evidence of effect, although the estimates were relatively imprecise. We suggest that future research should emphasize validity studies, especially those of differential reporting, rather than replicating existing analyses of the relationship between maternal smoking and clefts. We discuss how our approach is also applicable to evaluating misclassification in a wide range of exposure-outcome scenarios.
View details for DOI 10.1097/EDE.0b013e31818ab3b0
View details for Web of Science ID 000261930800007
View details for PubMedID 19234399
In a California population, we previously observed increased neural tube defect (NTD) risks associated with maternal intakes of periconceptional diets predicting higher glycaemic responses and higher sucrose. Our objective here was to replicate these results in a larger study of multiple regions within the United States. This population-based case-control study included deliveries from 1997 to 2003 from the National Birth Defects Prevention Study. NTD cases were infants or fetuses born with spina bifida or anencephaly. Infants without malformations were eligible as controls. Interview participation was 71% among case mothers and 68% among control mothers. There were 720 NTD case and 4699 control mothers with completed interviews included in analyses. Diet was assessed using a 58-item food frequency questionnaire focusing on the year before conception, whereas cereals, beverages and supplement use was assessed periconceptionally. We found no increased risks of NTD-affected pregnancies with increased intakes (adjusted for kcal/day) of sucrose, glucose, fructose or with maternal diets with a higher glycaemic load. The reasons for current findings to be inconsistent with previous findings are unknown.
View details for DOI 10.1111/j.1365-3016.2008.00964.x
View details for Web of Science ID 000259818200003
View details for PubMedID 19000288
Prevalences of NTDs are typically 50-100% greater among Hispanic women compared to non-Hispanic Whites. This article examines whether markers of acculturation such as "language preference" allow the identification of high-risk groups within the Hispanic population. It also examines whether known NTD risk factors explain observed differences in risk among Hispanic women who are more and less acculturated.This population-based case-control study of deliveries in selected California counties from 1999-2003 included 337 NTD cases and 626 nonmalformed, liveborn controls.Relative to less acculturated US-born Hispanic women (i.e., women who preferred reading and speaking Spanish), other subgroups (i.e., US-born Hispanic women who preferred English, foreign-born Hispanic women regardless of "language preference", and non-Hispanic White women) had approximately twofold increased risks of spina bifida. Only the less acculturated foreign-born women (i.e., women with a preference for Spanish) had substantially increased risk of anencephaly (OR 1.7; 95% CI 0.9, 3.4). Adjustment for several NTD risk factors (maternal intake of folic acid-containing supplements, dietary folate intake, body mass index, food insecurity, stressful life events, smoking, alcohol intake, education, income, and neighborhood education and poverty) resulted in modest or no reductions in most of the ORs.The explanation for variability in NTD risks among Hispanic and non-Hispanic White women therefore likely extends beyond most known NTD risk factors.
View details for DOI 10.1002/bdra.20517
View details for Web of Science ID 000261567200004
View details for PubMedID 18985703
Periconceptional folic acid can reduce the occurrence of neural tube defects (NTDs) by up to 70%, and autoantibodies for folate receptors (FRs) have been observed in serum from women with a pregnancy complicated by an NTD. This population-based cohort study has examined serum from pregnant mothers for autoantibodies to FRs, antibodies to bovine folate binding protein (FBP), and inhibition of folic acid binding to FR and FBP in association with NTD risk. The mid-gestational maternal serum specimens used for this study were collected during the 15-18th week of pregnancy. Samples were obtained from the California Birth Defects Monitoring Program; 29 mothers had a pregnancy complicated by spina bifida and 76 mothers had unaffected children. The presence of IgG and IgM antibodies to human FR, bovine FBP, and inhibition of folic acid binding to FR and FBP was determined. Higher activity of IgM to FBP in cases verses controls was observed (P=0.04). Higher activity of IgM and IgG autoantibodies to FR was observed (P<0.001 and P=0.04, respectively). Risk estimates at two standard deviations above average control antibody concentrations were OR=2.07 (CI=1.02, 4.06) for anti-FBP IgM, OR=2.15 (CI=1.02, 4.69) for anti-FR IgG and OR=3.19 (CI=1.47, 6.92) for anti-FR IgM. These data support the hypothesis that high titers of antibodies and blocking of folic acid binding to FRs by maternal serum should be regarded as risk factors for NTDs.
View details for DOI 10.1016/j.jri.2008.08.002
View details for Web of Science ID 000260989000012
View details for PubMedID 18804286
The objective of this study was to characterize the prevalence, demographic risk factors, and malformations associated with agenesis and hypoplasia of the corpus callosum diagnosed in infancy. Using a large population-based registry of birth defects, we ascertained 630 cases of agenesis (ACC) and hypoplasia (HCC) of the corpus callosum diagnosed in the first year of life among 3.4 million live births from 1983 to 2003. Infants with destructive lesions or specific complex central nervous system (CNS) malformations (neural tube defects, lissencephaly, and holoprosencephaly) were excluded. Multivariable Poisson regression analysis was used to examine demographic risk factors. The combined prevalence of ACC and HCC was 1.8 per 10,000 live births. Fifty-two percent of cases were male. Infants with ACC had an almost fourfold higher prevalence among infants born prematurely when compared with children born > or =37 weeks gestation (RR 3.7, 95% CI 2.5-5.3). After adjusting for paternal age, advanced maternal age >/=40 years was associated with ACC in infants with a chromosomal disorder (ACC RR 5.9; 95% CI 1.8-19.3, HCC RR 3.5; 95% CI 0.9-14.1). Paternal age was not significantly associated with ACC after adjusting for maternal age. Callosal anomalies were often seen in the context of a chromosomal abnormality (17.3%) and with accompanying somatic (musculoskeletal 33.5% and cardiac 27.6%) and CNS malformations (49.5%). Callosal anomalies form a clinically significant and relatively frequent group of malformations of the CNS that are associated with increased risk of premature birth, are more common with advanced maternal age and are frequently part of a complex, multisystem disorder.
View details for DOI 10.1002/ajmg.a.32418
View details for Web of Science ID 000260202700007
View details for PubMedID 18642362
Moderate hyperhomocysteinemia is a known risk factor for NTDs in a variety of experimental model systems and is believed to be important in humans as well. The enzyme nicotinamide N-methyl transferase (NNMT) was identified in a genome-wide linkage scan as being an important regulator of homocysteine homeostasis in a Spanish population, making it an interesting candidate gene for NTDs.We evaluated 11 SNPs (single nucleotide polymorphism) of the NNMT gene in our study population. In this study, 252 cases (infants with spina bifida) and 335 controls (nonmalformed infants), born during the period 1983-1986 in selected counties in California, were genotyped for variants of the NNMT gene. Allelic, genotype, and haplotype associations with spina bifida risk were evaluated and analyzed.None of the SNPs studied alone showed allelic or genotypic associations with spina bifida. However, the TCAG haplotype for block 3 (rs2852447, ra2852425, rs4646337, and rs11569688) showed a decreased risk for spina bifida among non-Hispanic Whites (OR 0.4; 95%CI: 0.1-1.0).No association was found between infant NNMT gene variants and risk for spina bifida in our study population. However, small sample sizes for most variant groups and for phase-unknown haplotype data limited the power of the study.
View details for DOI 10.1002/bdra.20474
View details for Web of Science ID 000260523300006
View details for PubMedID 18553462
Gastroschisis is a severe major malformation in which an infant is delivered with a portion of intestines and possible other abdominal organs extruding through a defect in the abdominal wall, usually to the right of the umbilical cord. Etiologies of gastroschisis are largely unknown, and even its pathogenesis is poorly understood. Several recent epidemiological studies have identified interactions between maternal smoking during pregnancy, genetic variants of endothelial nitric oxide synthase, and risk for gastroschisis. We present a brief review of the endothelial nitric oxide synthase pathway and its relationship to vasculogenesis, suggesting that disruption of this pathway by environmental exposures or by genetic variation may represent one pathogenetic model for gastroschisis.
View details for DOI 10.1002/ajmg.c.30182
View details for Web of Science ID 000258293400007
View details for PubMedID 18655103
In many regions, NTD prevalences were already declining prior to folic acid fortification. This study examined whether the declining prefortification (1989-1996) NTD prevalences continued into the postfortification period (1998-2003) in selected California counties.This population-based study used vital statistics data and birth defects registry data that were actively ascertained from medical records. The study population included all live births and stillbirths delivered in central California counties from 1989 to 2003. Cases included deliveries with NTDs during the same time period.For all NTDs combined, the slopes indicated that NTD prevalence was decreasing by 7.5 (slope: -7.5; 95% CI: -12.4, -2.5) cases per 100,000 deliveries per year before fortification, whereas NTD prevalence was no longer decreasing after fortification. Comparison of the difference in the two slopes indicated that the postfortification slope exceeded the prefortification slope by 12.6 (95% CI: 2.6, 22.6) cases per 100,000 deliveries per year.Annual NTD prevalences in central California did not continue to decrease after implementation of folic acid fortification.
View details for DOI 10.1002/bdra.20466
View details for Web of Science ID 000258763500001
View details for PubMedID 18496833
This study examined the association between maternal smoking and alcohol use (including binge drinking) during the periconceptional period (i.e., 2 months before through 2 months after conception) and the risk of orofacial clefts, NTDs, and conotruncal heart defects in offspring.Data were drawn from a population-based case-control study of fetuses and live-born infants among a cohort of California births between July 1999 and June 2003. The 1,355 cases comprised of 701 orofacial clefts, 337 NTDs, and 323 conotruncal heart defects. Information on smoking and alcohol consumption was obtained via telephone interviews with mothers of 1,355 (80% of eligibles) cases and 700 (77% of eligibles) nonmalformed, live-born controls.Maternal smoking of five cigarettes or less per day was associated with reduced risks of NTDs (OR 0.7; 95% CI: 0.3, 1.4), whereas the risk associated with higher cigarette consumption was lower for conotruncal heart defects (OR 0.5; 95% CI: 0.2, 1.2). Maternal intake of alcohol less than 1 day per week was associated with a 1.6- to 2.1-fold higher risk of NTDs (95% CI: 0.9, 2.6), d-transposition of the great arteries (95% CI: 1.1, 3.2), and multiple cleft lip with or without cleft palate (CLP) (95% CI: 0.8, 4.5). Risks associated with more frequent alcohol intake were 2.1 for NTDs (95% CI: 1.1, 4.0) and 2.6 for multiple CLP (95% CI: 1.1, 6.1).This study observed that maternal alcohol intake increased the risk for d-transposition of the great arteries, NTDs, and multiple CLP in infants. By contrast, smoking was associated with a lower risk of NTDs and conotruncal heart defects.
View details for DOI 10.1002/bdra.20461
View details for Web of Science ID 000257906800004
View details for PubMedID 18481814
The role that nutritional factors play in mammalian development has received renewed attention over the past two decades as the scientific literature has exploded with reports that folic acid supplementation in the periconceptional period can protect embryos from a number of highly significant malformations. As is often the case, the relationship between B vitamin supplementation and improved pregnancy outcomes is more complicated than initially perceived, as the interaction between nutritional factors and selected genes must be considered. In this review, we attempt to summarize the complex clinical and experimental literature on nutritional factors, their biological transport mechanisms, and interactions with genetic polymorphisms that impact early embryogenesis. While not exhaustive, our goal was to provide an overview of important gene-nutrient interactions, focusing on folic acid and vitamin B12, to serve as a framework for understanding the multiple roles they play in early embryogenesis.
View details for Web of Science ID 000257425800011
View details for PubMedID 18709884
To evaluate time trend of gastroschisis and examine the epidemiological risk factors for gastroschisis.This population-based study analyzed the active surveillance data from the California Birth Defects Monitoring Program from 1987 to 2003.The overall birth prevalence of gastroschisis was 2.6 cases per 10,000 births (908 cases in >3.5 million births). In the adjusted analysis, by using the age of 25 to 29 years as the reference, mothers aged 12 to 15 years had a 4.2-times greater birth prevalence (95% CI, 2.5-7.0), and fathers aged 16 to 19 years and 20 to 24 years had 1.6- and 1.5-times greater birth prevalence (95% CI, 1.1-2.1 and 1.2-1.8), respectively. Compared with non-Hispanic whites and US-born Hispanic, both foreign-born Hispanics and blacks had adjusted prevalence ratio of 0.6 (95% CI, 0.5-0.7 and 0.4-0.9, respectively). In addition, nulliparity was also associated with gastroschisis. Independent of maternal age, paternal age, and maternal ethnicity, the birth prevalence increased 3.2-fold (95% CI, 2.3-4.3) during the 17-year study period.The birth prevalence of gastroschisis continues to increase in California, and young, nulliparous women are at the greatest risk of having a child with gastroschisis.
View details for DOI 10.1016/j.jpeds.2007.11.037
View details for Web of Science ID 000256373800018
View details for PubMedID 18492521
Several previous studies suggested increased risk of craniosynostosis among infants born to women who smoked.This study used data from the National Birth Defects Prevention Study, a multi-state, population-based case-control study of infants delivered from 1997-2003. Nonmalformed, liveborn controls were selected randomly from birth certificates or birth hospitals. Data from maternal telephone interviews were available for 531 cases and 5008 controls.Smoking during the first month of pregnancy was not associated with craniosynostosis. Smoking later in pregnancy was associated with increased risk, but only among mothers who smoked at least one pack/day. For example, during the second trimester, the odds ratio for smoking <5 cigarettes/day was 1.0 (95% confidence interval [CI] 0.6, 1.8), but the odds ratio (OR) for smoking 15 or more cigarettes/day was 1.6 (95% CI 0.9, 2.8), after adjustment for maternal age, education, race-ethnicity, sub-fertility, parity, folic acid supplement intake, body mass index, and study center. Among women who did not smoke, adjusted odds ratios suggested that secondhand smoke exposure at home, but not at work/school, was associated with modestly increased risk; the OR for home exposure was 1.3 (95% CI 0.9, 1.9). Results followed a similar pattern for some, but not all, specific suture types, but numbers for some groupings were small.The results suggest moderately increased risk of craniosynostosis among mothers who were the heaviest smokers and who continued to smoke after the first trimester. Results are somewhat equivocal, given that most confidence intervals included one.
View details for DOI 10.1002/bdra.20426
View details for Web of Science ID 000253624800002
View details for PubMedID 18050313
This study examined individual and household socioeconomic status (SES) in relation to phenotypes of neural tube defects, orafacial clefts, and conotruncal heart defects using data from the National Birth Defects Prevention Study with 2,551 nonmalformed liveborn controls and 1,841 cases delivered in 1997-2000. The individual SES was measured by maternal and paternal education, occupation, and household income. All individual SES measures were combined to create a household SES index. Elevated risks were found for maternal low education in association with anencephaly and dextrotransposition of the great arteries (dTGA) (adjusted odds ratios (AORs) > or = 1.4); paternal low education in association with anencephaly, cleft palate, tetralogy of Fallot (TOF), and dTGA (AORs > or = 1.4); low household income in association with TOF (AOR = 1.4, 95% confidence interval (CI): 0.8, 2.5); maternal operator/laborer occupation in association with cleft palate, TOF, and dTGA (AORs > or = 1.4); paternal operator/laborer occupation in association with spina bifida (AOR = 1.4, 95% CI: 1.0, 2.0); and either parent's unemployment in association with dTGA (AOR > or = 1.4). Subjects with the lowest household SES index had the greatest risks of all selected birth defects except TOF. This study reveals consistently increased risks of selected birth defects in association with household SES index but not individual SES measures.
View details for DOI 10.1093/aje/kwm283
View details for Web of Science ID 000252498200003
View details for PubMedID 17947220
The purpose of this study was to examine whether maternal corticosteroid use during pregnancy is associated with delivering an infant with an orofacial cleft.This study included data on deliveries from the National Birth Defects Prevention Study, which is a population-based case-control study. Exposures were assessed by telephone interviews for mothers of 1141 cases with cleft lip +/- cleft palate (CLP), 628 with cleft palate (CP), and 4143 controls.Mothers of 33 infants with CLP (2.9%), mothers of 6 infants with CP (1.0%), and 72 control subjects (1.7%) reported corticosteroid use from 4 weeks before through 12 weeks after conception. The crude odds ratio for "any" vs "no" use was 1.7 (95% CI, 1.1-2.6) for CLP and 0.5 (0.2-1.3) for CP. When analyzed by route of administration and medication components, odds ratios for CLP tended to be elevated, and odds ratios for CP tended to be close to 1.Our results suggest a moderately increased risk of CLP among women who use corticosteroids during early pregnancy.
View details for DOI 10.1016/j.ajog.2007.05.046
View details for Web of Science ID 000251675700008
View details for PubMedID 18060943
Investigations for co-occurring malformations can serve as a first step to discover new risk factors and provide insights into malformation etiologies. Our objective was to explore the risks of occurrence of structural congenital malformation phenotypes in 5,481 infants with hypospadias, using data from a population-based active surveillance system. Ascertainment was performed among 1,816,258 liveborn and 12,203 stillborn male offspring of women who were residents of registry counties during 1983-1997. Malformations other than hypospadias were grouped according to the 3- and 4-digit BPA malformation codes. Prevalences of each malformation grouping were calculated among all births with hypospadias and their three subgroups and all births without hypospadias but with another structural malformation. Relative risks were estimated based on the ratio of two prevalences, and the corresponding 95% confidence intervals were computed using Poisson regression models. Observed relative risks indicated that all malformation groupings were less likely to co-occur with hypospadias and their three subgroups than with other types of malformations, with relative risks ranging from 0.04 to 0.93. For most malformations, risks were relatively similar among all births with hypospadias and the three subgroups of hypospadias. The observed relative risks were not substantially changed in analyses that adjusted for maternal age, race/ethnicity, and parity. Computations were extended to 4-digit level BPA codes. Almost all observed relative risks for malformations co-occurring with hypospadias overall and three subgroups were less than 1.
View details for DOI 10.1002/ajmg.a.32001
View details for Web of Science ID 000250708900001
View details for PubMedID 17937439
There is a paucity of information about risk factors for the human eye anomalies anophthalmia and microphthalmia. In this population-based case-control study we investigated whether periconceptional intakes of supplemental folic acid, dietary folate, vitamin A, and several other nutrients were associated with these eye defects.This study included data on deliveries that had estimated due dates from 1997-2002 and were part of the National Birth Defects Prevention Study (the National Birth Defects Prevention Study is a population-based case-control study of a wide spectrum of birth defects, incorporating data from 10 birth defects surveillance systems in the United States [Arkansas, California, Georgia/Centers for Disease Control and Prevention, Iowa, Massachusetts, New Jersey, New York, North Carolina, Texas, and Utah]). Cases were those infants or fetuses born with either anophthalmia or microphthalmia. Liveborn infants without major malformations were eligible as controls. Maternal interviews were conducted, primarily by telephone, in English or Spanish. Participation in the interview was 71% among case mothers and 68% among control mothers. Interviews were completed with 89 case mothers and 4,143 control mothers. A shortened version of the food frequency questionnaire from the Nurse's Health Study was used to assess frequency of intake of 58 food items during the year before pregnancy.Our results did not indicate reduced risks for these eye malformations associated with maternal intake of vitamin supplements containing folic acid. The data did not show an association between malformation risk and higher or lower intakes of vitamin A. We also did not observe strong evidence that an abundance or a lack of dietary intake of any other nutrient was associated with increased risk of the studied eye malformations.Our observations contribute to a limited body of findings on these rare eye defects.
View details for DOI 10.1002/bdra.20398
View details for Web of Science ID 000250222400007
View details for PubMedID 17847120
The occurrence of preterm delivery has been increasing in the U.S. Previous studies have identified risk factors for preterm delivery that may have genetic influences. We conducted a case-control study comparing the frequencies of 49 genetic polymorphisms among 62 preterm infants and 553 term infants. The polymorphisms that we examined were involved in xenobiotic-metabolism, blood pressure, coagulation, the inflammatory response, cell-cell interaction, or folate-homocysteine metabolism. Univariate analyses on the individual polymorphisms revealed a statistically significant effect for the variant genotypes compared to the wildtype genotypes in SERPINE1 11053G > T (OR = 0.4, 95% CI = 0.2-0.8). This finding suggests the coagulation/thrombophilic pathway may influence the development of preterm delivery.
View details for DOI 10.1002/ajmg.a31868
View details for Web of Science ID 000249173900007
View details for PubMedID 17676631
Food insecurity represents a lack of access to enough food to meet basic needs. We hypothesized that food insecurity may increase birth defect risks, because it is an indicator of increased stress or compromised nutrition, which are both implicated in birth defect etiologies. This study used population-based case-control data. Included in the analysis were 1,189 case mothers and 695 control mothers who were interviewed by telephone. We calculated a food insecurity score as the number of affirmative responses to 5 questions from a shortened instrument designed to measure food insecurity. OR for the food insecurity score specified as a linear term indicated that a higher score was associated with increased risk of cleft palate, d-transposition of the great arteries, tetralogy of Fallot, spina bifida, and anencephaly, but not with cleft lip with or without cleft palate, after adjustment for maternal race-ethnicity, education, BMI, intake of folic acid-containing supplements, dietary intake of folate and energy, neighborhood crime, and stressful life events. In addition, several models suggested effect modification by certain factors. For example, for anencephaly, among women with the worst score for neighborhood crime (i.e. 6), the OR associated with a 1-unit change in the food insecurity score was 1.57 (95% CI 1.06, 2.33), whereas among women with a low crime score (i.e. 2), the corresponding OR was 1.16 (95% CI 0.96, 1.38). This study suggests that increased risks of certain birth defects may be included among the negative consequences of food insecurity.
View details for Web of Science ID 000249110600016
View details for PubMedID 17709447
Congenital diaphragmatic hernia (CDH) is a common, life threatening birth defect. Although there is strong evidence implicating genetic factors in its pathogenesis, few causative genes have been identified, and in isolated CDH, only one de novo, nonsense mutation has been reported in FOG2 in a female with posterior diaphragmatic eventration. We report here that the homozygous null mouse for the Pdgfralpha gene has posterolateral diaphragmatic defects and thus is a model for human CDH. We hypothesized that mutations in this gene could cause human CDH. We sequenced PDGFRalpha and FOG2 in 96 patients with CDH, of which 53 had isolated CDH (55.2%), 36 had CDH and additional anomalies (37.5%), and 7 had CDH and known chromosome aberrations (7.3%). For FOG2, we identified novel sequence alterations predicting p.M703L and p.T843A in two patients with isolated CDH that were absent in 526 and 564 control chromosomes respectively. These altered amino acids were highly conserved. However, due to the lack of available parental DNA samples we were not able to determine if the sequence alterations were de novo. For PDGFRalpha, we found a single variant predicting p.L967V in a patient with CDH and multiple anomalies that was absent in 768 control chromosomes. This patient also had one cell with trisomy 15 on skin fibroblast culture, a finding of uncertain significance. Although our study identified sequence variants in FOG2 and PDGFRalpha, we have not definitively established the variants as mutations and we found no evidence that CDH commonly results from mutations in these genes.
View details for DOI 10.1038/sj.ejhg.5201872
View details for Web of Science ID 000249144200008
View details for PubMedID 17568391
To describe the relation between maternal obesity, overweight and underweight status, and 16 categories of structural birth defects.An ongoing multisite, case-control study. Clinical geneticists reviewed all of the cases, excluding those that had or were strongly suspected to have a single-gene disorder or chromosomal abnormality. Mothers with preexisting diabetes were also excluded. Body mass index was based on maternal report of height and weight prior to pregnancy.Eight participating states in the United States.Mothers enrolled in the National Birth Defects Prevention Study who had index pregnancies between October 1, 1997, and December 31, 2002.Maternal obesity.Crude and adjusted odds ratios.Mothers of offspring with spina bifida, heart defects, anorectal atresia, hypospadias, limb reduction defects, diaphragmatic hernia, and omphalocele were significantly more likely to be obese than mothers of controls, with odds ratios ranging between 1.33 and 2.10. Mothers of offspring with gastroschisis were significantly less likely to be obese than mothers of controls.To our knowledge, this is the first population-based study of its scale to examine prepregnancy obesity and a range of structural birth defects. These results suggest a weak to moderate positive association of maternal obesity with 7 of 16 categories of birth defects and a strong inverse association with gastroschisis. The mechanisms underlying these associations are not yet understood but may be related to undiagnosed diabetes.
View details for Web of Science ID 000248583000003
View details for PubMedID 17679655
To examine the interactions between four fetal xenobiotic metabolizing gene polymorphisms, maternal cigarette smoking, and risk for oral cleft defects.California population-based case-control study of 431 infants born with isolated orofacial clefts and 299 nonmalformed controls.Infants were genotyped for functional polymorphisms of the detoxification enzymes microsomal epoxide hydrolase-1 (EPHX1 T-->C [Tyr113His], and A-->G [His139Arg]), and glutathione-S transferase Pi-1 (GSTP1 A-->G [Ile105Val] and C-->T [Ala114Val]), and risks for cleft outcomes were measured for gene only and gene-maternal smoking effects.Although smoking was associated with an increased risk for isolated cleft lip+/-palate, we found no independent associations of genotypes of EPHX1-codon 113 or GSTP1-codon 105 polymorphisms for either isolated cleft lip+/-palate or isolated cleft palate. The heterozygote genotype for the EPHX1-codon 139 polymorphism was associated with an increased risk of isolated cleft palate (odds ratio=1.6 [95% confidence interval, 1.0 to 2.6]). Infant EPHX1 and GTSP1 polymorphic variants did not appreciably alter the risks for clefts associated with maternal smoking, nor were any EPHX1 combined genotype-specific risks found. Infant genotypes of the GSTP1-codon 105 polymorphism, combined with glutathione-S-transferase-mu-1 null genotypes, did not appreciably alter the risk of orofacial clefts.Our results suggest that genetic variation of the detoxification enzymes EPHX1 and GSTP1 did not increase the risks of orofacial clefting, nor do they influence the risks associated with maternal smoking.
View details for DOI 10.1597/06-011.1
View details for Web of Science ID 000248295300003
View details for PubMedID 17608547
This study examined the association of hypospadias risk with several maternal reproductive and demographic characteristics: age, parity, body mass index (BMI), nausea and vomiting of pregnancy (NVP), multiple pregnancy, fertility treatments and procedures, education and race-ethnicity. The study included data on deliveries with estimated due dates from October 1997 to December 2000 that were part of the National Birth Defects Prevention Study, a multi-state case-control study of many birth defects. The analysis included 502 cases with second or third degree hypospadias (i.e. the urethra opened at the penile shaft, scrotum or perineum) and 1286 male, liveborn, non-malformed controls. Risks were estimated from a multivariable logistic regression model that included all exposures of interest. Results indicated particularly elevated risks among births to women who were primiparae, aged >or=35 years and had a BMI of >26, compared with women who were multiparae, aged <30 years and had a BMI of
View details for Web of Science ID 000245676100003
View details for PubMedID 17439529
View details for Web of Science ID 000245676100003
View details for PubMedID 17439529
Several previous studies suggest that maternal stress may be associated with increased risk of certain birth defects. This study examined the association of maternal stressful life events with risks of several birth defects.The data are from a recent, population-based case-control study. Telephone interviews were conducted with 1355 eligible case mothers and 700 control mothers. Maternal stress was measured by responses to 18 yes/no questions about life events that occurred from 2 months before through 2 months after conception.An increase in the stressful life events index (ie, number of "yes" responses to the 18 life-events questions) was associated with increased risk of cleft palate, cleft lip with or without cleft palate, d-transposition of the great arteries, and tetralogy of Fallot, after adjustment for maternal race-ethnicity, education, obesity, age, smoking, drinking, intake of folic acid-containing supplements, neighborhood crime, and food insecurity. For example, the odds ratio for a 3-unit change in the stress index was 1.45 (95% confidence interval = 1.03-2.06) for cleft palate. Increased stress was associated with an increased risk of spina bifida and anencephaly particularly among women who did not take folic acid supplements. A 3-unit change in stress was associated with a 2.35-fold increased risk of anencephaly among women who did not take supplements (CI =1.47-3.77) and a 1.42-fold increased risk among women who did (CI = 0.89-2.25).The adverse health effects of stress may include increased risks of certain birth defects.
View details for DOI 10.1097/01.ede.0000259986.85239.87
View details for Web of Science ID 000245993300010
View details for PubMedID 17435445
PAX3 plays an important role in mammalian embryonic development. Known mutations in PAX3 are etiologically associated with Waardenburg syndrome and syndromic neural tube defects (NTDs). Mutations in the murine homologue, pax3, are responsible for the phenotype of splotch mice, in which nullizygotes are 100% penetrant for NTDs.The study sample included 74 infants with spina bifida (cases) and 87 nonmalformed infant controls. The conserved paired-box domain as well as the upstream genomic region of PAX3 were subjected to resequencing and those identified SNPs were evaluated as haplotypes. The associations of haplotypes for selected gene regions and the risks of spina bifida were further studied.Nineteen SNPs were observed; 15 observed in controls had been submitted to the National Center for Biotechnology Information (NCBI) database with allele frequencies. The PAX3 gene variant T-1186C (rs16863657) and its related haplotype, TCTCCGCCC of nine SNPs, were found to be associated with an increased risk of spina bifida, with an OR of 3.5 (95% CI: 1.2-10.0) among Hispanic Whites.Our analyses indicated that PAX3 SNPs were not strong risk factors for human spina bifida. However, additional follow-up of the PAX3 gene variant T-1186C (rs16863657) and its related haplotype, TCTCCGCCC, may be important in other populations.
View details for DOI 10.1002/bdra.20322
View details for Web of Science ID 000243314500007
View details for PubMedID 17149730
We investigated whether infants with homozygous genotype TT of the MTHFR gene were at increased risk of severe mental retardation.One hundred children with severe mental retardation (cases) were investigated from a large geographic-based study of infants born in California in 1992-1993. Cases were compared to 743 randomly selected nonmalformed control infants born in California during 1987-1991. DNA was extracted from newborn screening filter papers. Cases and controls were genotyped TT if homozygous for the MTHFR C677T allele, CT if heterozygous for the C677T allele, and CC if homozygous for the C677 (wild type) allele.Overall, case and control infants had similar percentages of TT and CT genotypes. Percentages between cases and controls differed somewhat across race/ethnic groups. Elevated ORs of 1.9 (95% CI: 0.7-5.0) and 2.6 (95% CI: 1.1-5.8) were observed for the TT and CT genotypes, respectively, among Hispanic children. Observed results were not substantially altered for analyses that removed 41 case children who also had structural birth defects.Folate-related mechanisms are important to investigate for etiologies of birth defects, and such lines of inquiry may be revealing for mental retardation given the relationships between mental retardation and birth defects and potential relationships between folate, DNA methylation, and mental retardation.
View details for DOI 10.1002/bdra.20321
View details for Web of Science ID 000243314500004
View details for PubMedID 17149733
This study explored risks of limb deficiency anomalies associated with 29 single nucleotide polymorphisms (SNPs) of genes involved in homocysteine metabolism, coagulation, cell-cell interaction, inflammatory response, and blood pressure regulation. The authors genotyped 96 cases and 437 non-malformed controls from a California population-based case-control study (1987-1988 birth cohort). Increased risk of limb anomaly was observed for three SNPs: heterozygosity for F5 Arg506Gln, with an odds ratio (OR) of 2.5 (95% confidence interval (CI), 1.0, 6.5); heterozygosity for TNF (-376)G > A, OR 2.1 (0.7, 6.2); and homozygosity for NPPA 2238T > C, OR 4.0 (1.1, 15.4). We hypothesized that effects of variant genotypes in the presence of maternal smoking, and/or in the absence of supplement intake, may exceed effects of any of these factors alone. In particular, findings for polymorphisms in SERPINE1, ITGA2, SELE, TNF, LTA, NPPA, GNB3, and ADRB2 supported the hypotheses, both for smoking and for supplement intake. These results suggest involvement of genetic variation of biologically relevant candidate genes, and gene-environment interaction, for some limb anomalies whose pathogenesis may be related to altered vascular tone or integrity.
View details for PubMedID 17036337
Increasing epidemiologic evidence suggests that genetic susceptibilities contribute to birth defects risks, especially in combination with other environmental exposures. This analysis examines the association of risk of limb deficiency defects with infant genotypes for N-acetyltranferases (NAT1, NAT2), glutathione-S-tranferases (GSTT1, GSTM1), and endothelial nitric oxide synthase (NOS3). The combined effects of infant genotype with maternal smoking and supplement intake were also examined. The authors genotyped 92 cases and 201 non-malformed controls from a California population-based case-control study (1987-1988 birth cohort). Several of the infant genotypes were associated with an at least 1.5-fold increased risk for limb deficiency defects: homozygosity for the NAT1 1088 and 1095 polymorphisms, heterozygosity and homozygosity for the NOS3 A(-922)G polymorphism, and heterozygosity (but not homozygosity) for the NOS3 G894T polymorphism. The authors hypothesized that the effects of selected variant genotypes in the presence of maternal smoking, or in the absence of supplement intake, may exceed effects of any of these factors alone. A few observations suggested that risks were greatest among infants with variant genotypes, whose mothers also smoked or did not take supplements, but most did not, and risk estimates were imprecise. Further studies exploring genetic susceptibility and combined gene-environment effects with respect to limb development will be important to continued improvement of our understanding of the etiology of limb anomalies.
View details for PubMedID 16906563
Neural tube closure takes place during early embryogenesis and requires interactions between genetic and environmental factors. Failure of neural tube closure is a common congenital malformation that results in morbidity and mortality. A major clinical achievement has been the use of periconceptional folic acid supplements, which prevents approximately 50-75% of cases of neural tube defects. However, the mechanism underlying the beneficial effects of folic acid is far from clear. Biochemical, genetic and epidemiological observations have led to the development of the methylation hypothesis, which suggests that folic acid prevents neural tube defects by stimulating cellular methylation reactions. Exploring the methylation hypothesis could direct us towards additional strategies to prevent neural tube defects.
View details for DOI 10.1038/nrn1986
View details for Web of Science ID 000240512500014
View details for PubMedID 16924261
A greatly neglected source of DNA potentially useful for genetic or forensic studies is the clot remaining from blood samples collected for serum chemistry measurements. We have investigated the utility of residual clots remaining from venipunctures collected for California's Expanded Maternal Serum Alpha-Fetoprotein Screening Program. We report a protocol based on the salting out method for the extraction of DNA from samples which have been archived and frozen for up to 2.5 years. As much as 57 microg of high-quality DNA can be obtained from a 2-ml clot as determined by PicoGreen (Molecular Probes, Inc., Eugene, OR) fluorescence measurements. Quality of the purified DNA was evaluated by its ability to serve as template in polymerase chain reaction (PCR) amplifications, using primers that flank the polymorphic regions of six genes of pharmacogenetic interest distributed throughout the human genome. Sizes of the gene regions successfully amplified range from 215 bp to 2064 bp, using as little as 10 ng of template DNA. Because many genotyping protocols routinely recommend the design of amplicons in the 100-200 bp range, and 10-50 ng of template, we conclude that the clot remaining after serum has been removed from blood collected for serum chemistry measurements can serve as a reliable source of DNA for genotyping studies.
View details for Web of Science ID 000236347300008
View details for PubMedID 16545003
Congenital diaphragmatic hernia (CDH) is a severe birth defect of unknown etiology. The aims of the current report were to extend the literature on the descriptive epidemiology of CDH and to determine whether its mortality rate decreased in California during the study period.Using data from a large population-based registry, we ascertained 631 CDH cases from 1989 to 1997. We also classified cases as isolated or nonisolated based on the presence and type of major accompanying malformations. Approximately 2.5 million live and stillbirths occurred during the ascertainment period. Multivariate Poisson regression analysis was applied to examine the time trend and risk factors.The overall prevalence of CDH was 2.49 per 10,000 live and stillbirths and did not vary over the study period. Isolated cases, which accounted for 58% of cases, revealed a prevalence of 1.45 per 10,000. Heart malformations were the most frequent major anomalies accompanying CDH. We observed a lower risk of isolated CDH among blacks. Advanced maternal age groups had a higher risk for nonisolated CDH. Multiparous women tended to have a lower risk for nonisolated CDH. Male infants and multiple births had an increased risk for isolated and nonisolated CDH. Infant mortality was slightly decreased over the study period. CDH cases with additional anomalies had higher mortality rates than isolated cases.Our observations add to the relatively few population-based descriptive epidemiologic studies of the prevalence and mortality, and maternal and infant characteristics of CDH.
View details for DOI 10.1002/bdra.20230
View details for Web of Science ID 000236494400003
View details for PubMedID 16511883
This study describes the timing and correlates of folic acid supplement intake among pregnant women.Data from 2518 women with estimated delivery dates from 1997 to 2000, collected for the National Birth Defects Prevention Study, a population-based case-control study, were analyzed. Multinomial logistic regression was used to identify correlates of supplement intake.Fifty-three percent of women began taking folic acid supplement during the periconceptional period, 35% during early pregnancy, and 8% during late pregnancy (ie, 3 months before through 1 month after conception, 2-3 months after conception, or more than 3 months after conception, respectively). Women who did not take folic acid supplement periconceptionally tended to be nonwhite, speak Spanish, have low education, be younger than 25 years old, be nulliparous, smoke, have no previous miscarriage and no fertility treatments, begin prenatal care and become aware of their pregnancy after the first trimester, have nonplanned pregnancies, and eat less breakfast cereal.This study identifies correlates of folic acid supplement intake, which may contribute to the design of interventions to improve intake during early pregnancy.
View details for DOI 10.1016/j.ajog.2005.06.018
View details for Web of Science ID 000234386200031
View details for PubMedID 16389033
Orofacial clefts have been associated with maternal cigarette smoking and lack of folic acid supplementation (which results in higher plasma homocysteine concentrations). Because endothelial nitric oxide synthase (NOS3) activity influences homocysteine concentration and because smoking compromises NOS3 activity, genetic variation in NOS3 might interact with smoking and folic acid use in clefting risk. The authors genotyped 244 infants with isolated cleft lip with or without cleft palate (CL/P), 99 with isolated cleft palate, and 588 controls from a California population-based case-control study (1987-1989 birth cohort) for two NOS3 polymorphisms: A(-922)G and G894T. Analyses of gene-only effects for each polymorphism revealed a 60% increased risk of CL/P among NOS3 A(-922)G homozygotes (odds ratio (OR) = 1.6, 95% confidence interval (CI): 1.0, 2.6). There was some evidence for higher risk of CL/P with maternal periconceptional smoking in infants with an NOS3 -922G allele (for homozygotes, OR = 2.5, 95% CI: 1.2, 5.6) but not in those with an 894T allele. For CL/P risk, odds ratios were over 4 among mothers who smoked, who did not use vitamins, and whose infants had at least one variant allele for each NOS3 polymorphism (for A(-922)G, OR = 4.6, 95% CI: 2.1, 10.2; for 894T, OR = 4.4, 95% CI: 1.8, 10.7). No similar patterns were observed for risk of cleft palate.
View details for DOI 10.1093/aje/kwi336
View details for Web of Science ID 000233850400009
View details for PubMedID 16269583
The few previous studies of hypospadias and smoking have suggested either no association or a reduced risk. This study, which uses data from the National Birth Defects Prevention Study, a multi-state, population-based case-control study, includes data on males born with severe hypospadias (i.e. the urethra opens at the penile shaft, scrotum or perineum) from 1997 to 2000. Non-malformed, liveborn male controls were selected randomly from birth certificates or from birth hospitals. Maternal interviews were completed by telephone with 453 case mothers and 1267 control mothers. Maternal smoking was not associated with hypospadias risk. For example, during the third month of pregnancy, smoking < 0.5 pack/day had an odds ratio (OR) of 1.1 [95% CI 0.6, 1.9]; 0.5 pack/day, 0.6 [0.4, 1.1]; and > or = 1 pack/day, 0.8 [0.4, 1.6]. Exposure to any secondhand smoke at home during the third month of pregnancy showed an OR of 0.6 [95% CI 0.4, 1.0], and exposure at work or school, an OR of 0.7 [0.5, 1.1]. Similar risks were observed for other months during the periconceptional period, and adjustment for several potential confounders did not substantially alter results. This analysis does not confirm a recent report suggesting that maternal smoking is associated with a reduced risk of having offspring with hypospadias.
View details for Web of Science ID 000233020700002
View details for PubMedID 16269066
Previous studies have suggested that maternal intake of progestins during early pregnancy may be associated with an increased risk of hypospadias. Progesterone and its derivatives are commonly prescribed during early pregnancy, for example, in cases of luteal phase dysfunction and in conjunction with ovulation stimulation drugs.To examine whether risk of hypospadias was associated with periconceptional progestin intake.The National Birth Defects Prevention Study, a population-based, multistate, case-control study including deliveries that had estimated due dates from October, 1997 to December, 2000.Participation in the study was 71% among case mothers and 68% among control mothers. This analysis included 502 subjects diagnosed with second- or third-degree hypospadias (ie, the urethra opened at the penile shaft, scrotum, or perineum) and 1286 male, live-born, nonmalformed control subjects.Forty-two case mothers (8.4%) and 31 control mothers (2.4%) reported any pregnancy-related progestin intake from 4 weeks before through 14 weeks after conception, resulting in an odds ratio of 3.7 (95% confidence interval [CI], 2.3-6.0). Analyses stratified by several potential covariates also suggested elevated risks. For example, among the 10 cases and 13 controls who did not report any fertility-related procedures or treatments other than progestins, the odds ratio was 2.2 (95% CI, 1.0-5.0). Progestin intake for the purpose of contraception was not associated with increased risk.This study found that pregnancy-related intake of progestins was associated with increased hypospadias risk.
View details for Web of Science ID 000232322000008
View details for PubMedID 16203941
Investigating possible genetic polymorphisms and gene-environment interactions in the etiology of human conotruncal defects is a prudent research approach. In this study we explore gene-only and gene-environment effects of 32 single nucleotide polymorphisms (SNPs) on conotruncal defect risks. The genes bearing these SNPs participate in one of five pathogenetic processes, homocysteine metabolism, coagulation, cell-cell interaction, inflammatory response, and blood pressure regulation. We used DNA samples and data from a California population-based case-control interview study (1987-1988 birth cohort). We employed a multilocus allele-specific hybridization assay. Allelic variants were determined by genotyping 155 infants with conotruncal defects (cases) and 437 infants without malformations (controls). Among the 32 SNPs, four were associated with odds ratios of 2 or more, and two with odds ratios of 0.5 or less. The four SNPs were F2 G20210A (prothrombin) with an odds ratio of 2.5 (95% confidence interval; 0.9-7.0), F7 promoter (-323) 10-bp del/ins with an odds ratio of 2.3 (0.8-6.8), ITGB3 leu33pro (platelet glycoprotein IIIa) with an odds ratio of 2.2 (0.9-5.7), and NPPA T2238C (atrial natriuretic precursor peptide) with an odds ratio of 2.9 (0.8-10.1). Two SNPs were associated with decreased risks: TNF (tumor necrosis factor, G (-376A)) and ADD1 gly460trp (alpha adducin) with odds ratios of 0.5 (0.1-2.3) and 0.5 (0.2-1.9), respectively. Analyses that investigated a potential gene-nutrient interaction between maternal periconceptional vitamin use and MTHFR genotypes did not indicate that the CT or TT genotype contributed to conotruncal defect risk in infants even in the absence of maternal use of multivitamin supplements with folic acid. Analyses that investigated a potential interaction on risk between NOS3 genes and maternal cigarette smoking, revealed some evidence for higher risk of conotruncal defects in infants whose mothers smoked cigarettes periconceptionally and who had one of the variant alleles for NOS3 A(-922G) or NOS3 glu298asp compared to those infants whose mothers did not smoke and whose genotypes were wild-type. Our results provide some support for involvement of genetic variation of biologically relevant candidate genes for some birth defects whose pathogenesis may be related to altered vascular tone or integrity. In particular, NPPA appears to be a good candidate gene for conotruncal defects and warrants further investigation.
View details for PubMedID 16100725
Maternal smoking is a known risk factor for orofacial clefts. We investigated whether risk is greater among offspring who lack the genetic capacity to produce glutathione S-transferase enzymes relevant to detoxification of chemicals in cigarette smoke.Using a population-based case-control design, we genotyped 423 California infants with an isolated cleft and 294 nonmalformed controls for null variants of the glutathione S-transferases GSTT1 and GSTM1.If a mother smoked during pregnancy and her fetus was homozygous null for GSTT1, the risk of isolated cleft lip with or without cleft palate was tripled (odds ratio = 2.9; 95% confidence interval = 1.2-7.2). For fetuses who were homozygous null for GSTM1 and whose mothers smoked >/=20 cigarettes per day, we found nearly a 7-fold increased risk (6.8; 0.82-57). Combined absence of GSTM1 and GSTT1 enzymes among the offspring of smoking mothers was associated with a nearly 6-fold increased risk for cleft lip (6.3; 1.3-42). A similar increased risk for cleft palate was associated with absence of GSTM1, but not for absence of GSTT1.Maternal smoking during pregnancy increases risks for clefts among fetuses lacking enzymes involved in the detoxification of tobacco-derived chemicals.
View details for DOI 10.1097/01.ede.0000172136.26733.4b
View details for Web of Science ID 000231783200017
View details for PubMedID 16135950
PRKACA and PRKACB are genes encoding the cAMP-dependent protein kinase A (PKA) catalytic subunits alpha and beta, respectively. PKA is known to be involved in embryonic development, as it down-regulates the Hedgehog (Hh) signaling pathway, which is critical to normal pattern formation and morphogenesis. The PKA-deficient mouse model, which has only a single catalytic subunit, provided intriguing evidence demonstrating a relationship between decreased PKA activity and risk for posterior neural tube defects (NTDs) in the thoracic to sacral regions of gene-knockout mice. Unlike most other mutant mouse models of NTDs, the PKA-deficient mice develop spina bifida with 100% penetrance. We hypothesized that sequence variations in human genes encoding the catalytic subunits may alter the PKA activity and similarly increase the risk of spina bifida.We sequenced the coding regions and the exon/intron boundaries of PRKACA and PRKACB. We also examined 3 common single-nucleotide polymorphisms (SNPs) of these 2 genes by allele discrimination.Five sequence variants in coding region and 2 intronic sequence variants proximal to exons were detected. None of the 3 SNPs examined in the association study appeared to be associated with substantially increased risk for spina bifida.Our results did not reveal a strong association between these PKA SNPs and spina bifida risk. Nonetheless, it is important to examine the possible gene-gene interactions between PRKACA and PRKACB when evaluating the risk for NTDs, as well as genes encoding regulatory subunits of PKA. In addition, interactions with other genes such as Sonic Hedgehog (SHH) should also be considered for future investigations.
View details for DOI 10.1002/bdra.20175
View details for Web of Science ID 000232323300002
View details for PubMedID 16080189
Schizencephaly is a rare congenital brain defect characterized by gray matter lined clefts of the cerebral mantle, frequently accompanied by other defects of the CNS such as absence of the corpus callosum. This study in a California population of >4 million births from 1985-2001 found a population prevalence of 1.54/100,000. Among 63 cases, there was an association with young parental age in isolated schizencephaly (RR 3.9 mothers; 5.8 fathers), which was also seen in mothers but not fathers of non-isolated cases (RR 3.2). Monozygotic twins may also be at increased risk for schizencephaly (RR 2.1). One third of cases had a non-CNS abnormality, over half of which could be classified as secondary to vascular disruption, including gastroschisis, bowel atresias, and amniotic band disruption sequence. Other apparent rare causes included chromosomal aneuploidy, non-random associations, and unusual syndromes. Our observations suggest that schizencephaly has heterogeneous etiologies many of which are vascular disruptive in origin.
View details for PubMedID 16059942
There is a paucity of epidemiologic information about the eye malformations anophthalmia and microphthalmia. Using data from a large population-based registry, we explored prevalences and maternal/infant characteristics associated with anophthalmia and bilateral microphthalmia. Data were derived from the California Birth Defects Monitoring Program, a population-based active surveillance system for collecting information on infants and fetuses with congenital malformations using multiple source ascertainment. Approximately 2.5 million births (liveborn and stillborn) occurred during the ascertainment period, 1989-1997. Information on maternal and infant/fetal characteristics was obtained from California birth certificate and fetal death files. The prevalence per 10,000 livebirths and stillbirths for anophthalmia was 0.18 and for bilateral microphthalmia was 0.22. These estimates reflect prevalences among births without chromosomal anomalies. Relative risks of anophthalmia were modestly higher among women aged 40 or more (relative risk = 2.0, 95% confidence interval 0.5-8.6). Risks were substantially lower for those mothers with >12 years of education, even after adjusting for other study factors, relative risk = 0.6 (0.2-1.7). The risk of anophthalmia was approximately twofold among multiple births compared to singletons. Similar to results for anophthalmia, decreased risks for bilateral microphthalmia were observed for maternal education of 12 years or more and increased risks observed for multiple births. These data show descriptive epidemiologic features of anophthalmia and bilateral microphthalmia.
View details for PubMedID 16007635
Individual and maternal characteristics as potential risk factors for having severe mental retardation (SMR) occurring with and without cerebral palsy (CP), epilepsy, or a pervasive developmental disorder (PDD) were explored among a cohort of 119,404 children without Down syndrome born in the California Central Valley in 1992 and 1993. Unadjusted and adjusted relative risks (RRs) and their 95% confidence intervals (CIs) based on the Poisson distribution were used to estimate the risks associated with each individual and maternal factor studied for each SMR diagnostic category. The most notable increased risks for SMR occurring in isolation or with CP or epilepsy was for children born low-birth-weight or preterm who were at a substantially increased risk (RRs 2.6-9.9). In contrast, the risk of SMR occurring with a PDD was the greatest among males compared to females (RR = 3.4, 95% CI 1.5, 7.9), Blacks compared to Whites (RR = 5.1, 95% CI 1.7, 15.5), and Asians compared to Whites (RR = 3.9, 95% CI 1.3, 12.0). Etiologic heterogeneity when SMR occurs with a PDD was suggested.
View details for PubMedID 15940698
Repairing DNA damage is critical during embryogenesis because development involves sensitive periods of cell proliferation, and abnormal cell growth or death can result in malformations. Knockout mouse experiments have demonstrated that disruption of DNA repair genes results in embryolethality and structural defects. Studies using mid-organogenesis rat embryos showed that DNA repair genes were variably expressed. It is hypothesized that polymorphisms that alter the functionality of DNA repair enzymes may modify the risk of malformations. We conducted a case-control analysis to investigate the relationship between DNA repair gene polymorphisms and the risk of spina bifida and oral clefts. Newborn screening blood spot DNA was obtained for 250 cases (125 spina bifida, 125 oral clefts) identified by the California Birth Defects Monitoring Program, and 350 non-malformation controls identified from birth records. Six single nucleotide polymorphisms of five DNA repair genes representing three distinct repair pathways were interrogated including: XRCC1 (Arg399Gln), APE1 (Asp148Glu), XRCC3 (Thr241Met), hOGG1(Ser326Cys), XPD (Asp312Asn, Lys751Gln). Elevated or decreased odds ratios (OR, adjusted for race/ethnicity) for spina bifida were found for genotypes containing at least one copy of the variant allele for XPD [751Gln, OR = 1.62; 95% confidence interval (CI) = 1.05-2.50] and APE 148 (OR = 0.58; CI = 0.37-0.90). A decreased risk of oral clefts was found for XRCC3 (OR = 0.62; CI = 0.39-0.99) and hOGG1 (326 Cys/Cys, OR = 0.22; CI = 0.06-0.78). This study suggested that polymorphisms of DNA repair genes, representing different major repair pathways, may affect risk of two major birth defects. Future, larger studies, examining additional repair genes, birth defects, and interaction with exposures are recommended.
View details for PubMedID 15887293
Maternal obesity and diabetes are both associated with increased risk of congenital central nervous system (CNS) malformations in the offspring and may share a common underlying mechanism. Our objective was to evaluate whether gestational diabetes influenced the association of prepregnancy maternal obesity and risks for CNS birth defects.This Texas population-based case-control study evaluated births occurring January 1997 through June 2001. Data came from structured telephone interviews. Cases (n=477) were mothers of offspring with anencephaly (n=120), spina bifida (n=184), holoprosencephaly (n=49), or isolated hydrocephaly (n=124). Controls (n=497) were mothers of live infants without abnormalities randomly selected from the same hospitals as cases. Response rates were approximately 60% for both cases and controls. We evaluated maternal obesity (body mass index > or =30.0 kg/m) and risks for CNS birth defects, as well as whether gestational diabetes influenced the risks.After adjusting for maternal ethnicity, age, education, smoking, alcohol use, and periconceptional vitamin use, obese women had substantially increased risks of delivering offspring with anencephaly (odds ratio=2.3; 95% confidence interval=1.2-4.3), spina bifida (2.8; 1.7-4.5), or isolated hydrocephaly (2.7; 1.5-5.0), but not holoprosencephaly (1.4; 0.5-3.8). Odds ratios were higher for the joint effects of maternal obesity and gestational diabetes, with evidence for interaction on a multiplicative scale.Maternal obesity and gestational diabetes may increase the risk of CNS birth defects through shared causal mechanisms.
View details for DOI 10.1097/01.ede.0000147122.97061.bb
View details for Web of Science ID 000226079600013
View details for PubMedID 15613950
Periconceptional supplementation of multivitamins that include folic acid have been shown to prevent several birth defects, including neural tube defects and orofacial clefts. We investigated whether polymorphic variants of fetal acetyl-N-transferase 1 (NAT1), an enzyme involved in the catabolism of folates, differentially interacted with maternal multivitamin use during early pregnancy to alter the risk of delivering an infant with an orofacial cleft malformation.Using a large population-based case-control study, we genotyped 421 California infants born with an isolated cleft and 299 controls for two NAT1 polymorphisms.Compared to the homozygous wild-type genotypes, odds ratios for isolated cleft lip with/without cleft palate were slightly increased among infants who were homozygous for the variant alleles of NAT1 1088 and 1095. For isolated cleft palate, no similar associations with these two NAT1 variants were observed. For NAT1 1088 genotypes, we did not observe any differential risks for clefts related to maternal multivitamin intake. For NAT1 1095 genotypes, however, we found a two-fold higher risk for isolated cleft lip with/without cleft palate among infants who were homozygous for the variant allele and whose mothers did not take multivitamins during early pregnancy.We found evidence suggestive of an interaction between the NAT1 1095 polymorphism and lack of maternal multivitamin use that increased risks of isolated cleft lip with/without cleft palate.
View details for DOI 10.1002/bdra.20081
View details for Web of Science ID 000225522500005
View details for PubMedID 15523664
Little is known about the occurrence of specific congenital malformations among offspring of mixed race-ethnicity.Using data from a population-based registry, we explored the occurrence of selected malformation phenotypes in offspring to parents who were of different race-ethnicity. Data were derived from the California Birth Defects Monitoring Program, a population-based active surveillance system for collecting information on infants and fetuses with congenital malformations using multiple source ascertainment. Approximately 2.6 million live births and stillbirths occurred during 1989-2000. Information on parental race-ethnicity (non-Hispanic white, Hispanic, black, and Asian) was obtained from birth certificates and fetal death files. Malformation phenotypes studied were spina bifida, anencephaly, cleft lip, cleft palate, tetralogy of Fallot, d-transposition of great arteries, hypospadias, small intestinal atresia, preaxial polydactyly, microtia, and hypertrophic pyloric stenosis.A total of 11.2% of births were to parents of mixed race-ethnicity. Compared to births of parents who were both white, moderately increased risks (risk ratio >/= 1.7) of anencephaly, polydactyly, and microtia, and decreased risks (risk ratio = 0.6) of hypospadias and hypertrophic pyloric stenosis were observed among births of several mixed race-ethnicity groups. For anencephaly, polydactyly, and microtia, but not other phenotypes, the risks were different depending on whether maternal versus paternal race-ethnicity was considered. Risks observed between births of a nonwhite parent and a white parent and births of parents who were both nonwhite were similar for most malformation phenotypes.Some malformation phenotypes appear to vary in their risk based on mixed racial-ethnic groupings.
View details for DOI 10.1002/bdra.20025
View details for Web of Science ID 000224970800005
View details for PubMedID 15390318
The role that nutritional factors play in mammalian development has received renewed attention over the past two decades, as the scientific literature exploded with reports of retinoid compounds disrupting craniofacial development, and with other reports that folic acid supplementation in the periconceptional period can protect embryos from highly significant malformations. As was often the case, the situation became far more complicated, as the interaction between nutritional factors with selected genes was recognized. In this review, we attempt to summarize a complex clinical and experimental literature of nutritional factors, their biological transport mechanisms, and the impact that they have during early embryogenesis. Although not exhaustive, our goal was to provide an overview of important gene-nutrient interactions and a framework for their investigation.
View details for DOI 10.1016/j.taap.2003.09.031
View details for Web of Science ID 000222713900001
View details for PubMedID 15236946
There is increasing evidence from epidemiologic studies that genetic susceptibilities may modify the teratogenic effects of smoking. A previous study suggested that maternal smoking in the presence of a dinucleotide repeat polymorphism for MSX1 produced an almost fivefold increased risk for limb anomalies, providing evidence for a gene-environment interaction. The current study examined this potential interaction, using case-control data with several methodologic improvements, including a larger sample size and more detailed information on cigarette smoke exposures. Cases (n = 92) were ascertained from pregnancies ending in 1987-1989, and controls (n = 180) were randomly selected from eligible liveborn infants. In telephone interviews, women reported smoking behaviors during the month before pregnancy through the end of the first trimester. Odds ratios (OR) for maternal and paternal smoking ranged from 1.0 to 1.4, risk estimates were imprecise; for example, the OR for maternal smoking >or=20 cigarettes per day, versus none, was 1.3 (95% confidence interval (CI) 0.5-3.4). Relative to the homozygous wildtype, the OR was 1.5 (95% CI 0.7-3.5) for the homozygous variant genotype and 0.8 (95% CI 0.5-1.4) for the heterozygous variant genotype. There was no evidence that maternal smoking or both parents smoking, in combination with a susceptible MSX1 genotype, conferred an additional increase in risk of limb defects. This study did not find a gene-environment interaction between maternal smoking, infant MSX1 CA repeat polymorphism, and risk of limb deficiency defects. This finding contrasts with results of a previous study, which provided initial evidence for such an interaction. Several important methodological differences may have contributed to the differences in findings between the two studies.
View details for DOI 10.1002/ajmg.a.20517
View details for Web of Science ID 000189316800011
View details for PubMedID 14994238
Orofacial clefts are etiologically heterogeneous malformations. One probable cause is maternal smoking during pregnancy. The effect of maternal smoking may be modified by genes involved in biotransformation of toxic compounds derived from tobacco. We investigated whether polymorphic variants of fetal acetyl-N-transferases 1 (NAT1) and 2 (NAT2) interact with maternal cigarette smoking during early pregnancy to increase the risk of delivering an infant with an orofacial cleft.In a California population-based case-control study, we genotyped 421 infants born with an isolated cleft and 299 nonmal-formed controls for 2 NAT1 and 3 NAT2 single nucleotide polymorphismsAlthough smoking was independently associated with increased risks for both isolated cleft lip +/- cleft palate and isolated cleft palate, no independent associations were found for NAT1 1088 or 1095 genotypes or for NAT2 acetylator status. However, the infant NAT1 1088 and 1095 polymorphisms were strongly associated with the risk of clefts among smoking mothers; infants with NAT1 1088 genotype AA versus TT (odds ratio [OR] = 3.9; 95% confidence interval = 1.1-17.2) and with NAT1 1095 genotype AA versus CC (OR = 4.2; 1.2-18.0). Infant NAT2 acetylator status did not appreciably affect susceptibility of the fetus to the teratogenic effects of maternal smoking.Our results suggest that maternal smoking during pregnancy may increase risk for orofacial clefts particularly among smokers whose fetuses have polymorphic variants of NAT1, an enzyme involved in phase II detoxification of tobacco smoke constituents.
View details for DOI 10.1097/01.ede.0000112214.33432.cc
View details for Web of Science ID 000189286900006
View details for PubMedID 15127906
The authors examined whether maternal dieting behaviors were associated with increased neural tube defect (NTD) risk among offspring, using population-based, case-control data. The analysis included 538 cases and 539 nonmalformed controls delivered from 1989 to 1991 in selected California counties, and exposures were assessed by in-person maternal interview. Among four reported dieting behaviors involving restricted food intake, diets to lose weight (odds ratio=2.1, 95% confidence interval: 1.1, 4.1), fasting diets (odds ratio=5.8, 95% confidence interval: 1.7, 20.0), and eating disorders (odds ratio=1.7, 95% confidence interval: 0.8, 3.6) were associated with increased NTD risk during the first trimester of pregnancy. Risk estimates for these behaviors during the 3 months before conception tended to be closer to 1. The fourth behavior, "other special diets," was not associated with increased NTD risk during either period. Women also reported whether they took diet pills, laxatives, or diuretics, engaged in binge eating, induced vomiting, or exercised excessively from the first 3 months before conception through the end of pregnancy. Only the intake of diuretics was associated with substantially increased NTD risk (odds ratio=2.7, 95% confidence interval: 0.7, 10.2). This study suggests that maternal dieting behaviors involving restricted food intake during the first trimester may be associated with increased NTD risk.
View details for Web of Science ID 000187216600001
View details for PubMedID 14652296
Polymorphisms within the thymidylate synthase (TS) gene that influence enzyme activity may affect plasma folate levels and, indirectly, plasma homocysteine concentrations. We investigated whether TS polymorphisms contribute to spina bifida (SB) risk, given that a reduction in the risk of SB has been linked to folate metabolism.Genomic DNA was extracted from newborn-screening blood spots obtained from case infants with SB, and randomly selected, nonmalformed control infants. Genotype frequencies of two polymorphisms in the TS gene-a 28-bp tandem repeat in the promoter enhancer region (TSER) and a 6-bp deletion in the 3'UTR-were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. Additionally, all seven exons of the TS gene were sequenced to identify variations within the coding region of the gene.We found that the TSER 2/2 homozygous genotype was associated with a slightly increased risk for SB infants (odds ratio [OR] = 1.4 [0.8-2.4], p = 0.1). When the cohort was divided into separate ethnic groups, this risk increased by 4-fold with the TSER 2/2 homozygous genotype (OR = 4.0 [1.8-8.8], p = 0.001), and by 3-fold with the 3'UTR +/+ homozygous genotype (OR = 3.6 [1.3-10.1], p = 0.02) in non-Hispanic white cases. The combined TSER,3'UTR (2/2,+/+) genotype showed a more than 4-fold increased risk for SB within this specific ethnic group (OR = 4.7 [1.1-19.8], p = 0.04).This study is the first to evaluate how TS polymorphisms contribute to the risk of SB. The current findings indicate that polymorphisms in the untranslated regions of the TS gene are associated with 4-fold or more increased risks of SB in non-Hispanic whites, but not in Hispanic whites, African-Americans, or Asian-Americans.
View details for DOI 10.1002/bdra.10029
View details for Web of Science ID 000186851600007
View details for PubMedID 14745930
The occurrence of hypospadias has been reported to be increasing. The objectives of this study were to extend the literature on the descriptive epidemiology of hypospadias and to determine whether its birth prevalence increased in California in recent years. We used actively ascertained, population-based data for which detailed clinical descriptions permitted careful phenotypic classifications.We examined registry data on 5838 male live births and stillbirths that occurred in California from 1984 through 1997. To reduce pathogenic heterogeneity, cases were classified as mild, severe, or not otherwise specified based on the anatomic position of the urethral opening. We also classified cases as isolated or nonisolated based on the presence and type of accompanying malformations. We used multivariable Poisson regression analysis to examine time trends and risk factors.There was no evidence for an increase in prevalence of any of the case groups between 1989 and 1997. The adjusted relative risk (RR) for change in prevalence per year of isolated severe cases was 0.99 (95% confidence interval = 0.96-1.03). Adjusted RRs indicated increased risks for specific types of hypospadias with maternal non-Hispanic white race-ethnicity, higher education, older age, and nulliparity. Delivery before 37 weeks and multiple births tended either not to be associated with risk or to be associated with reduced risk. Lower birthweight was associated with increased risk for all case groups.This study suggests that hypospadias prevalence has not been increasing in California in recent years. Differences by phenotype suggest that examining certain phenotypes separately could help to understand hypospadias etiology.
View details for DOI 10.1097/01.ede.0000091603.43531.d0
View details for Web of Science ID 000186160300011
View details for PubMedID 14569186
Maternal diabetes, prepregnancy obesity, hyperinsulinemia, and intakes of sweets have been associated with increased risks of neural tube defects (NTDs). The interdependence of these factors suggests a common pathogenesis via altered glycemic control and insulin demand.We investigated whether maternal periconceptional dietary intakes of sucrose, glucose, fructose, and foods with higher glycemic index values influence the risk of having NTD-affected pregnancies.In a population-based case-control study, all hospitals in 55 of the 58 counties in California participated. In-person interviews were conducted with the mothers of 454 NTD cases (including fetuses and infants who were electively terminated, stillborn, or born alive) and with the mothers of 462 nonmalformed controls within an average of 5 mo from the term delivery date. The risk of having an NTD-affected pregnancy was the main outcome measure.Risks of having an NTD-affected pregnancy were not substantially elevated in relation to periconceptional intakes of glucose or fructose. Elevated risks of approximately 2-fold were observed for higher intakes of sucrose and foods with higher glycemic index values. Elevated risks were observed for high sucrose intake irrespective of whether adjustment was made for other covariates such as maternal folic acid intake. For higher glycemic index values, adjusted elevated risks of > or = 4-fold were observed in women whose body mass index (in kg/m(2)) was > 29.Our observed associations support observations that potential problems in glucose control are associated with NTD risk even among nondiabetic women.
View details for Web of Science ID 000186146500013
View details for PubMedID 14594784
How folate reduces the risks of congenital anomalies is unknown. The authors focused on a gene involved in folate transport-reduced folate carrier-1 gene (RFC1). Using data from a California case-control study (1987-1989 births), the authors investigated whether the risks of orofacial clefts or conotruncal heart defects were influenced by a polymorphism of infant RFC1 or by an interaction between the RFC1 gene and maternal periconceptional use of vitamins containing folic acid. A total of 305 liveborn infants with cleft lip with or without cleft palate, 123 with cleft palate, 163 with conotruncal heart defects, and 364 nonmalformed controls were genotyped. Odds ratios of 1.6 (95% confidence interval: 0.9, 2.8) for the G80/G80 genotype and of 2.3 (95% confidence interval: 1.3, 3.9) for the G80/A80 genotype were observed relative to the A80/A80 genotype for conotruncal defects. Among mothers who did not use vitamins, the risk of conotruncal defects was 2.1 (95% confidence interval: 0.7, 5.9) for infants with genotype G80/G80 compared with those with the A80/A80 genotype. Among mothers who did use vitamins, the risk was 1.3 (95% confidence interval: 0.7, 2.7). Substantially elevated risks for either cleft group were not observed irrespective of genotype and use/nonuse of vitamins. Thus, this study found modest evidence for a gene-nutrient interaction between infant RFC1 genotype and periconceptional intake of vitamins on the risk of conotruncal defects.
View details for DOI 10.1098/aje/kwg189
View details for Web of Science ID 000185897700005
View details for PubMedID 14561664
In this study we investigated whether the risk of delivering infants with conotruncal heart defects was increased among mothers who consumed alcohol during the periconceptional period (i.e., 1 month before conception to 3 months after conception).Data were obtained from a population-based case-control study of California births from 1987-1988. Information concerning alcohol consumption was obtained via telephone interviews with mothers of 207 (87% of eligibles) case infants and 481 (76%) nonmalformed control infants.Bivariate results indicated that relative to nonconsumers, women who consumed alcohol less than once a week had a 1.3-fold increased risk of delivering infants with a conotruncal heart defect (95% confidence interval (CI) 1.0, 1.9), and women who consumed alcohol once a week or more had a 1.9-fold increased risk (95% CI 1.0, 3.4). The risks associated with consuming five or more drinks per drinking occasion were 1.6 (95% CI 0.8, 3.2) for less than once a week, and 2.4 for once a week or more (95% CI 0.6, 9.7). The results for the phenotypic subgroups were similar to those for all cases. Adjustment for potential covariates resulted in somewhat weaker, but still elevated, risks.This study found that the risk of conotruncal heart defects in offspring was moderately elevated among women who consumed alcoholic beverages during the periconceptional period, and that risk was higher with increased frequency of drinking or increased number of drinks consumed per occasion. Most of the risk estimates were imprecise, and chance could not be ruled out as an explanation for the observed findings.
View details for DOI 10.1002/bdra.10087
View details for Web of Science ID 000186148500007
View details for PubMedID 14745941
A paucity of epidemiologic research exists concerning the co-occurrence of birth defects and mental retardation (MR). Study of this co-occurrence may yield important clues about the causes of both.To examine the co-occurrence of birth defects and MR, taking into consideration the type of birth defect, level of MR, co-occurrence of MR with other developmental disabilities, and individual and maternal factors.A retrospective cohort study of infants born in the California Central Valley with and without a structural birth defect by 1 year of age, and with or without MR by 7 to 9 years of age. Setting andOne-year survivors (N = 119 556) born in nonmilitary hospitals in 8 California counties between January 1, 1992, and December 31, 1993, for whom information about birth defects was recorded within the first year of life.Diagnosis of MR by age 7 years considered as being mild or severe and as occurring without other developmental disabilities (isolated MR) or as occurring with other developmental disabilities, including cerebral palsy, epilepsy, or a pervasive developmental disorder.Children with birth defects were nearly 27 times more likely to have MR by 7 years of age compared with children without a diagnosed birth defect regardless of type of defect (prevalence ratio, 26.8; 95% confidence interval, 22.7-31.7). Among those with birth defects, children with Down syndrome (prevalence ratio, 211.7; 95% confidence interval, 171.3-261.5) and children with sex chromosomal defects (prevalence ratio, 57.4; 95% confidence interval, 23.7-138.6) were at the highest risk for MR. Children with nonchromosomal defects, including central nervous system defects and all types of organ and system defects, were at substantially increased risk for all levels of MR. Risks of MR among children with Down syndrome and nonchromosomal defects were not substantially altered when adjusted for individual and maternal factors.Children with chromosomal and other structural birth defects are at a substantially increased risk for having MR by 7 years of age compared with children born without a birth defect. Children with birth defects are at an especially increased risk for having severe MR and MR occurring independently of other developmental disabilities.
View details for Web of Science ID 000183408900007
View details for PubMedID 12796234
This study sought to determine whether a change in twinning prevalence was associated with mandatory folic acid fortification. As of January 1998, it became mandatory in the United States that grain products be fortified with folic acid. The effectiveness of this fortification for neural tube defects has been explored, but other possible implications of fortification has not. We computed the prevalence of twinning among more than 2.5 million California births occurring from 1990 to 1999. The prevalence of twin births in California increased over the last decade with increases observed among most maternal race/ethnic, age, and parity groupings. Unadjusted prevalence measures did not reveal substantial increases in twinning prevalence among these groupings after the fortification period relative to the period immediately preceding it. Analyses that simultaneously adjusted for age, parity, race/ethnicity, sexes of twin pair (as a measure of zygosity), year of birth, and fortification period also did not reveal an association between fortification and twinning. Our results do not suggest a change in twinning prevalence associated with folic acid fortification of the US food supply among women delivering in California.
View details for DOI 10.1002/ajmg.a.20145
View details for Web of Science ID 000182930600006
View details for PubMedID 12749051
Craniosynostosis, a malformation caused by premature closure of 1 or more cranial sutures, is a rare birth defect usually of unknown cause; however, it is often associated with advanced maternal age. Because fertility treatments are also associated with increased maternal age, this study investigated the possible association between fertility treatments and craniosynostosis.Data from the Birth Defect Risk Factor Surveillance study were used, which included infants who were delivered from 1993 through 1997 in California, Georgia, and Iowa. Cases were defined as infants who had nonfamilial, nonsyndromic craniosynostosis and were ascertained through existing birth defect surveillance systems. Controls, infants without birth defects, were selected from the same regions and time period.Mothers of 99 case infants and 777 control infants from the 3 study locations participated in this study by completing a telephone interview. Unadjusted analyses showed associations with craniosynostosis for mothers who had used clomiphene citrate (odds ratio[OR]: 3.8; 95% confidence interval [CI]: 1.1-12.3), artificial insemination (OR: 4.2; 95% CI: 0.8-9.4), or assisted reproductive techniques (OR: 4.2; 95% CI: 0.5-27.3).This is the first study that has found associations between fertility treatments and craniosynostosis. However, the numbers are small; therefore, the results should be viewed with caution.
View details for Web of Science ID 000182579700008
View details for PubMedID 12728131
In a case-control study using an assessment of occupational tasks by an industrial hygienist, the authors investigated whether women's occupational exposures increased risks of delivering infants with cleft palate (CP), cleft lip with or without cleft palate (CLP), conotruncal defects, or limb deficiencies. For CP and CLP, exposures were further considered in the presence/absence of infant genetic variants for glutathione-S-transferase M1, glutathione-S-transferase T1, and N-acetyltransferases 1 and 2. The study included 1987-1989 California stillbirths and livebirths. Telephone interviews were conducted with mothers of 662 CLP and CP cases, 207 conotruncal defect cases, 165 limb deficiency cases, and 734 nonmalformed controls. Occupational tasks were assigned to a priori-defined exposure categories: 74 chemical groups and nine "end-use" chemical groups. Odds ratios of 1.5 or greater were observed for a small number of exposure-defect comparisons. Risks associated with end-use groups revealed odds ratios of 1.5 or greater for exposures to dyes and pigments (conotruncal and CP), propellants (CP), and insecticides (conotruncal and CP). Numerous odds ratios of 2.5 or greater were observed for combined effects of exposures and homozygous mutant genotypes, particularly for CP. Although potential associations were observed, most results suggested that maternal occupational chemical exposures did not contribute substantially to the occurrence of these anomalies in this California population.
View details for Web of Science ID 000181611600001
View details for PubMedID 12631536
Several studies have suggested that homozygosity for the C677T 5,10-methylenetetrahydrofolate reductase (MTHFR) variant is a potential risk factor for neural tube defects (NTDs), as individuals homozygous for the C677T allele have slightly elevated homocysteine concentrations under conditions of low folic acid intake. It has been hypothesized that maternal folic acid supplementation prevents NTDs by partially correcting reduced MTHFR activity associated with the variant form of the enzyme.Genomic DNA was extracted from newborn screening blood spots obtained from 145 infants with spina bifida (SB) and 260 nonmalformed control infants. The MTHFR C677T genotype was determined by restriction enzyme digestion of PCR amplification products with Hinf1. We investigated whether infant MTHFR genotype influenced the risk for the anatomic level of the SB lesion (high vs. low); we also explored whether maternal vitamin use influenced this risk.Compared to controls, the frequency of SB infants with the homozygous 677 TT genotype was greatest in those infants with high level SB defects (26%; odds ratio [OR] = 2.9; 95% confidence interval [CI] = 0.9-10.1) than for those with low level SB defects (22%; OR = 1.8; 95% CI = 0.9-3.2). Furthermore, homozygous 677TT infants whose mothers did not use vitamins containing folic acid had a modestly increased risk of SB (OR = 1.8; 95% CI = 0.8-3.9), with this risk increasing more than three-fold (OR = 5.5; 95% CI = 0.8-28.1) for those infants with high level SB defects whose mothers did not use vitamins.Based upon our observations, it is suggested that the association between the infant MTHFR homozygous variant genotype and spina bifida risk may be conditional upon both lesion level and maternal vitamin use.
View details for DOI 10.1002/bdra.10008
View details for Web of Science ID 000185286600002
View details for PubMedID 12797455
Folic acid supplementation can effectively reduce the risk of neural tube defects (NTDs); however, the mechanism underlying this beneficial effect remains unclear. Recent evidence suggests that certain folate pathway genes, as well as those related to homocysteine metabolism might be contributing to this effect. The purpose of this study is to investigate whether gene polymorphisms of methionine synthase (MTR) and methionine synthase reductase (MTRR) are involved in the risk for NTDs, specifically spina bifida. We detected MTR A2756G and MTRR A66G polymorphisms using PCR-RFLP analysis in a group of NTD infants, their mothers and normal controls. We found that infants with the MTRR mutant genotype had a 2.6-fold higher risk of NTDs when compared to the AA genotype (OR = 2.6, 95%CI = 1.3-5.3). Mothers with the MTRR mutant genotype also had a 1.9-fold higher risk of having an NTD baby compared to AA genotype (OR = 1.9, 95%CI = 1.1-3.1). Infants who carry mutant alleles for both MTRR and MTR had exceptionally elevated NTD risks, with odds ratios of 5.1 compared to infants with the wild type genotype at both loci (AA + AA) (OR = 5.1, 95%CI = 1.7-15.4). A comparable result was observed in the mothers of NTD cases (OR = 2.1, 95%CI = 1.0-4.7). Our results indicate that MTRR and MTR genes may interact to increase the infants' NTD risks. These results did not appear to be influenced by maternal periconceptional folic acid intake. However,the sample size of this study was limited, and a larger population study is needed to pursue these initial observations.
View details for DOI 10.1016/S1096-7192(03)00008-8
View details for Web of Science ID 000181975800007
View details for PubMedID 12649067
Many studies have examined the impact of single nutrients on neural tube defect (NTD) risk, particularly folate. The impact of dietary patterns or nutrients in combination has received much less attention. This study examines the association of diet quality with NTD risk, using food frequency data from a population-based case-control study of NTDs (n=454 cases and 462 controls). The diet quality score was based on low (<10th percentile among controls) versus high (>90th percentile) values for intakes of iron, vitamins B(6) and A, calcium, folate, and percentage of kilocalories from fat and from sweets (range=0-14). Women with a low score (i.e., <4, or <10th percentile) had an elevated risk of an NTD-affected pregnancy (odds ratio 1.6, 95% CI 1.0-2.6). Stratified analyses suggested that the effect may be restricted to certain groups of women who may be at greater nutritional risk (i.e., women who did not take vitamin supplements or regularly consume breakfast cereals before pregnancy).
View details for DOI 10.1016/S0306-9877(02)00402-4
View details for Web of Science ID 000181152100012
View details for PubMedID 12581611
Concerns about potential health effects of trihalomethanes (THMs) have prompted investigations on whether infants whose mothers were periconceptionally exposed to drinking water containing THMs are at greater risk of congenital malformations.We used two large case-control maternal interview studies that were conducted among California deliveries from 1987 through 1991. One study comprised 538 infants/fetuses with neural tube defects (NTDs) and 539 nonmalformed control infants. The second study included an additional 265 infants with NTDs, 207 infants with conotruncal heart defects, 409 infants with orofacial clefts, and 481 control infants. Expert personnel from municipal water companies estimated THM levels for a particular residence and specific periconceptional time period using quarterly monitoring measurements. Estimates were also made for four individual THM levels and for the total THM level.NTD risk in the first study was inversely associated with total THM exposure. Although the second study did not show the same inverse relationship for NTDs, there were no positive associations of NTDs or the other malformations with total THM as estimated from continuous models. Elevated risks were observed for the lowest category of exposure (1-24 ppb), but risks were either not substantially elevated or were imprecise for higher exposure levels. Thus no evidence was observed for an exposure-response relation.Our results do not provide a clear pattern of association between THM exposure and risks of specific congenital malformations. Imprecise exposure measures coupled with a lack of information about other possible sources of THM exposure may have caused associations to be underestimated.
View details for Web of Science ID 000181174300012
View details for PubMedID 12606885
The contribution of social support and social networks to risk of neural tube defects (NTDs) has not been explored, despite evidence that various aspects of the social environment contribute to their etiology. Using data from a population-based case-control study of deliveries occurring in California from 1989 to 1991, this study investigates whether social networks, as measured by the presence and frequency of various types of social contacts, are associated with NTD risk. In-person interviews were conducted with 538 (88% of eligible) mothers of NTD cases and with mothers of 539 non-malformed controls (88%) on average 5 months from the term delivery date. Unadjusted results indicate that women who reported having close friends, close relatives, or monthly contacts with close friends or relatives had 30-70% lower risks of having NTD-affected pregnancies, relative to women reporting 'none' to any of these measures. Only the presence of close friends was associated with reduced NTD risk after adjustment for other aspects of the social network and several potential covariates. This study is the first to investigate the association between social networks and risk of NTDs. Stronger inferences await replication and extension of these results.
View details for Web of Science ID 000182005200006
View details for PubMedID 12733834
Although previous studies provide some evidence that timing of prenatal care initiation is associated with risks of congenital malformation, the issue has not previously been examined in depth. This study uses data from a large population-based registry to explore the association of timing of prenatal care initiation with risks of selected congenital malformation phenotypes.Data on cases were grouped according to four-digit malformation codes of the International Classification of Diseases, Ninth Revision (ICD-9). A randomly selected group of 10,000 nonmalformed deliveries served as the comparison group. Information on month of initiation of prenatal care (categorized as during months 1-3 of gestation, months 4-7, or after month 7) and other maternal characteristics were derived from vital statistics data.Among the 176 four-digit ICD groupings, 67 had an adjusted odds ratio for at least one of the two prenatal care categories that was either < or = 0.67 or > or = 1.50. Later prenatal care initiation was associated with risk > or = 1.50 for most groups. Later care was associated with risk < or = 0.67 for only two groups, and the effects were imprecise. Statistical interaction between parity and prenatal care was indicated for 13 groups (P < 0.10). Risks among women with no previous pregnancy tended to increase with later prenatal care initiation; risks among parous women tended to be somewhat weaker. In general, associations applied to a wide range of malformation groups.This is the first large-scale study of the association of timing of prenatal care initiation and congenital malformation risks. Further defining the phenomena that surround prenatal care as a marker may help clarify the etiologies of a variety of malformations.
View details for DOI 10.1002/tera.10117
View details for Web of Science ID 000180093600010
View details for PubMedID 12486766
The mechanisms by which folic acid may contribute to reductions in risk of several congenital anomalies are unknown. The data gap includes a lack of information on possible effect modification between maternal folic acid use and other maternal exposures. We hypothesized that effects of congenital anomalies associated with maternal fever, cigarette smoking or alcohol use would be modified by intake of vitamins.We explored case-control data that showed risk reductions among infants and fetuses whose mothers consumed vitamins. Data were from California deliveries of infants and fetuses in the period 1987-1989. Maternal telephone interviews were completed for 207 (87%) conotruncal cases, 489 (85%) orofacial cleft cases, 265 (84%) neural tube defect cases, 165 (82%) limb anomaly cases, and 734 controls (nonmalformed infants).Considering women who reported vitamin use and no periconceptional fever as referents, for each anomaly group we observed elevated effects for the combinations of maternal vitamin use/fever, no use/no fever and no use/fever. Effects were most elevated for the combination of no vitamin use and fever. Adjusted for maternal body mass index, education and race/ethnicity, odds ratios were 2.4 (95% confidence inter-val = 1.0-5.9) for conotruncal defects, 2.9 (1.4-5.8) for cleft lip with or without cleft palate, 1.3 (0.4-3.9) for cleft palate, 3.1 (1.4-6.8) for neural tube defects, and 2.6 (1.0-6.4) for limb-deficiency defects. These interactions were further investigated relative to maternal use of fever-reducing medications. Effects tended to be highest among those women who did not use vitamins, had fevers, and did not use fever-reducing medications. Compared with women who used vitamins and did not smoke periconceptionally, anomaly risks tended to be highest among women who did not use vitamins and smoked. No specific pattern emerged involving alcohol intake.These data further suggest that the underlying mechanisms of folic acid associated with congenital anomalies may be complex.
View details for DOI 10.1097/01.EDE.0000032431.83648.8D
View details for Web of Science ID 000178637200005
View details for PubMedID 12410002
Altered cholesterol metabolism and defects in cholesterol biosynthesis may influence abnormal central nervous system (CNS) development. During early stages of embryonic development, high levels of cholesterol are needed by rapidly proliferating cells that utilize cholesterol as a key cell membrane component. Alterations in cholesterol levels are influenced by variations in the apolipoprotein E (apoE) and apolipoprotein B (apoB) genes. The purpose of our study was to explore the possible association between infant genetic variations in the apoE and apoB genes and spina bifida (SB) risk.Genomic DNA was extracted from newborn screening blood spots obtained from 26 infants with SB and 73 non-malformed control infants. ApoE and apoB genotypes were determined by restriction enzyme digestion of PCR amplification products.Genotype frequencies for the apoE and apoB polymorphisms were not statistically different between case and control infants. For each apoB polymorphism, however, the frequency of the wild-type allele was higher in SB infants as compared to controls. Additionally, the apoE genotype E2/E3 was observed more frequently in the controls than in SB infants [15% in controls compared to 4% in cases; OR = 0.2 (0-1.6)].Results from this study suggest that genetic variations in the apoE and apoB genes, known to regulate cholesterol metabolism, do not substantially contribute to the risk of SB in infants.
View details for DOI 10.1002/tera.10097
View details for Web of Science ID 000178997500011
View details for PubMedID 12397634
Selected paternal occupations as well as specific occupational exposures to chemicals such as organic solvents have been suggested as possible risk factors for neural tube defects (NTD). We investigated data from a population-based, case-control study of fetuses and liveborn infants with NTDs among 1989-91 California births and fetal deaths. Interviews were conducted with mothers of 538 NTD cases and 539 non- malformed controls. Mothers were asked to report the occupations that the fathers had in the period 3 months before and 3 months after conception. Each job title and industry reported was coded in accordance with the 1990 US Census. Considering those fathers who worked in managerial and professional occupations as the reference group, elevated odds ratios (OR) for NTDs were observed for the categories: technical, sales and administrative, OR = 1.5 [95% confidence interval 1.0, 2.4]; service, OR = 2.0 [1.2, 3.1]; farming, forestry and fishing, OR = 2.1 [1.3, 3.3]; operators, fabricators and labourers, OR = 1.8 [1.2, 2.7]; and military, OR = 1.9 [0.7, 5.0]. Stratification by NTD phenotype revealed that these elevated ORs were primarily observed for spina bifida phenotypes. Analyses adjusted for maternal body mass index, maternal periconceptional use of multivitamins containing folic acid, paternal race/ethnicity, maternal race/ethnicity and maternal education revealed attenuated risk estimates for most of the occupational groups. Analyses of 182 more specific occupational groups defined by aggregating fathers on similar job titles, when compared with fathers who worked in managerial and professional occupations, revealed that four job title groups were associated with fairly precise effect estimates of >or=1.5. These groups were: cooks; janitors and cleaners; farm workers; and groundsmen/gardeners. Using occupational titles as defined in previous investigations, we did not observe an elevated OR associated with paternal occupational solvent exposures, OR = 0.8 [0.5, 1.3]. These analyses generated potential clues regarding paternal occupational exposures as NTD risk factors. Risk variation observed by spina bifida phenotype is interesting and will need to be investigated further.
View details for Web of Science ID 000179413600007
View details for PubMedID 12445149
Advances in quantitative analysis and molecular genotyping have provided unprecedented opportunities to add biological sampling and genetic information to epidemiologic studies. The purpose of this article is to describe the incorporation of DNA sample collection into the National Birth Defects Prevention Study (NBDPS), an ongoing case-control study in an eight-state consortium with a primary goal to identify risk factors for birth defects.Babies with birth defects are identified through birth defects surveillance systems in the eight participating centers. Cases are infants with one or more of over 30 major birth defects. Controls are infants without defects from the same geographic area. Epidemiologic information is collected through an hour-long interview with mothers of both cases and controls. We added the collection of buccal cytobrush DNA samples for case-infants, control-infants, and their parents to this study.We describe here the methods by which the samples have been collected and processed, establishment of a centralized resource for DNA banking, and quality control, database management, access, informed consent, and confidentiality issues.Biological sampling and genetic analyses are important components to epidemiologic studies of birth defects aimed at identifying risk factors. The DNA specimens collected in this study can be used for detection of mutations, study of polymorphic variants that confer differential susceptibility to teratogens, and examination of interactions among genetic risk factors. Information on the methods used and issues faced by the NBDPS may be of value to others considering the addition of DNA sampling to epidemiologic studies.
View details for DOI 10.1002/tera.10086
View details for Web of Science ID 000178375100006
View details for PubMedID 12353214
In 1992, the United States Public Health Service recommended that all women of childbearing age consume 400 microg of folic acid daily. The Food and Drug Administration authorized the addition of synthetic folic acid to grain products in March 1996 with mandatory compliance by January 1998. The impact of these public health policies on the prevalence of neural tube defects needs to be evaluated. We sought to determine the prevalences of spina bifida and anencephaly during the transition to mandatory folic acid fortification.Twenty-four population-based surveillance systems were used to identify 5,630 cases of spina bifida and anencephaly from 1995-99. Cases were divided into three temporal categories depending on whether neural tube development occurred before folic acid fortification (January 1995 to December 1996), during optional fortification (January 1997 to September 1998), or during mandatory fortification (October 1998 to December 1999). Prevalences for each defect were calculated for each time period. Data were also stratified by programs that did and did not ascertain prenatally diagnosed cases.The prevalence of spina bifida decreased 31% (prevalence ratio [PR] = 0.69, 95% confidence interval [CI] = 0.63-0.74) from the pre- to the mandatory fortification period and the prevalence of anencephaly decreased 16% (PR = 0.84, 95% CI = 0.75-0.95). Stratification by prenatal ascertainment did not alter results for spina bifida but did impact anencephaly trends.The decline in the prevalence of spina bifida was temporally associated with folic acid fortification of US grain supplies. The temporal association between fortification and the prevalence of anencephaly is unclear.
View details for DOI 10.1002/tera.10060
View details for Web of Science ID 000176651400007
View details for PubMedID 12115778
Despite the fact that neural tube defects (NTDs) are the most common congenital malformations of the central nervous system, investigators have yet to identify responsible gene(s). Research efforts have been productive in the identification of environmental factors, such as periconceptional folic acid supplementation, that modulate risk for the development of NTDs. Studies of the folic acid biosynthetic pathway led to the discovery of an association between elevated levels of homocysteine and NTD risk. Researchers subsequently identified single nucleotide polymorphisms in the gene coding for the enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR). Association studies suggested it was a potential risk factor for NTDs, because the thermolabile form of the enzyme led to elevated homocysteine concentrations when folic acid intake is low. Numerous studies analyzing MTHFR variants have resulted in positive associations with increased NTD risk only in certain populations, suggesting that these variants are not large contributors to the etiology of NTDs. With our limited understanding of the genes involved in regulating NTD susceptibility, the paucity of data on how folic acid protects the developing embryo, as well as the observed decrease in birth prevalence of NTDs following folic acid supplementation and food fortification, it makes little sense for prospective parents to be tested for MTHFR variants, or for variants of other known folate pathway genes.
View details for Web of Science ID 000176105200008
View details for PubMedID 12180076
Women who consume folic acid in early pregnancy reduced their risks for delivering offspring with neural tube defects (NTDs). The underlying process by which folic acid facilitated this risk reduction is unknown. Investigating genetic variation that influences cellular absorption, transport, and metabolism of folate will help fill this data gap. We focused our studies on a candidate gene that is involved in folate transport, the reduced folate carrier 1 (RFC1). Using data from a California population-based case control interview study (1989-1991 birth cohorts), we investigated whether spina bifida risk was influenced by an interaction between a polymorphism of infant RFC1 at nucleotide 80 (A80G) and maternal periconceptional use of vitamins containing folic acid. Allelic variants of RFC1 were determined by genotyping 133 live-born spina bifida case infants and 188 control infants. The percentages of case infants with the A80/A80, G80/G80, and G80/A80 genotypes were 27.2%, 28.0%, and 44.7%, respectively. The percentages of control infants were similar: 26.1%, 29.3%, and 44.7%. Odds ratios of 1.0 (95% confidence interval 0.5-2.0) for the G80/G80 genotype and 1.1 (0.6-2.0) for the G80/A80 genotype were observed relative to the A80/A80 genotype. Among mothers who did not use vitamins, spina bifida risk was 2.4 (0.8-6.9) for infants with genotype G80/G80 compared to those with A80/A80 genotype. Among mothers who did use vitamins, the risk was 0.5 (0.1-3.1) for infants with the G80/G80 genotype. Although this study did not find an increased spina bifida risk for infants who were heterozygous or homozygous for RFC1 A80G, it did reveal modest evidence for a gene-nutrient interaction between infant homozygosity for the RFC1 G80/G80 genotype and maternal periconceptional intake of vitamins containing folic acid on the risk of spina bifida.
View details for Web of Science ID 000173503500001
View details for PubMedID 11857541
Maternal cigarette smoking during the first trimester of pregnancy is associated with an increased risk of having a child with an oral cleft. Compounds present in cigarette smoke undergo bioactivation and/or detoxication. Phase I of this process results in the formation of reactive epoxides, which can form DNA adducts initiating and promoting mutagenesis, carcinogenesis, or teratogenesis. Microsomal epoxide hydrolase (mEH; gene symbol EPHX1) catalyzes hydrolysis of epoxides. Phase II involves attachment of a moiety (e.g., glutathione) to the compound mediated by a variety of enzymes, including glutathione S-transferase, generally resulting in a decreased reactivity. Recent studies suggest an association between the EPHX1 codon 113 polymorphism or homozygous null GSTM1 allele and the risk of carcinogenesis, emphysema, phenytoin-associated oral clefting, and the risk of spontaneous abortion. This study explores the association between EPHX1 codon 113 and homozygous null GSTM1 genotypes and oral clefting among infants whose mothers smoked during pregnancy. Case infants were diagnosed with isolated cleft lip with or without cleft palate (CL/P). EPHX1 codon 113 allelotyping was performed on 195 samples (85 cases, 110 controls) by PCR/RFLP analysis. 130 samples (79 cases, 51 controls) were tested for the GSTM1 homozygous null genotype using PCR. Using the odds ratio as a measure of association, we did not observe elevated risks of CL/P associated with either allelic comparison. This suggests that when mothers smoke periconceptionally, their infants having these alleles at either (or both) loci were not at substantially increased risk for CL/P compared to infants with the wild-type alleles.
View details for Web of Science ID 000169706400004
View details for PubMedID 11471167
The proportion of preterm births associated with structural birth defects has not been adequately quantified. We explored the proportion of preterm infants with structural birth defects diagnosed in the first year of life, as well as the specific phenotypes of birth defects occurring among preterm infants. The data used were from the California Birth Defects Monitoring Program, a population-based registry, as well as data from California vital records corresponding to births and fetal deaths in the period 1984-96. The prevalence of structural birth defects exceeded 8% among deliveries with gestational ages < or = 30 weeks, and prevalence decreased to 2% as gestational age increased to > or = 37 weeks gestation. The decreasing prevalence pattern with increasing gestational age was observed for a variety of anatomically defined birth defect groups suggesting that certain birth defects were not the sole contributors to the elevated prevalences among preterm births. Decreasing prevalence with increasing gestational age was also observed across strata of maternal race/ethnicities, ages, infant's sex and each year studied. These data indicate that structural birth defects may contribute significantly to the proportion of infants who are delivered before 37 weeks gestation.
View details for Web of Science ID 000168980500003
View details for PubMedID 11383574
In this population-based case-control study conducted in California between June 1989 and May 1991, the authors investigated the association between maternal periconceptional exposure to nitrate from drinking water and diet and risk for neural tube defects. The mothers of 538 cases and 539 nonmalformed controls were interviewed regarding residential history, consumption of tap water at home, and dietary intake during the periconceptional period. Dietary nitrate exposure was not associated with increased risk for neural tube defects. Exposure to nitrate in drinking water at concentrations above the 45 mg/liter maximum contaminant level was associated with increased risk for anencephaly (odds ratio (OR) = 4.0, 95% confidence interval (CI): 1.0, 15.4), but not for spina bifida. Increased risks for anencephaly were observed at nitrate levels below the maximum contaminant level among groundwater drinkers only (OR = 2.1, 95% CI: 1.1,4.1 for 5-15 mg/liter; OR = 2.3, 95% CI: 1.1, 4.5 for 16-35 mg/liter; and OR = 6.9, 95% CI: 1.9, 24.9 for 36-67 mg/liter compared with <5 mg/liter). Adjustment for identified risk factors for anencephaly did not substantially alter these associations, nor did control for maternal dietary nitrate, total vitamin C intake, and quantity of tap water consumed. The lack of an observed elevation in risk for anencephaly in association with exposure to mixed water containing nitrate at levels comparable with the concentration in groundwater may indicate that something other than nitrate accounts for these findings.
View details for Web of Science ID 000166886400004
View details for PubMedID 11207149
Maternal nutritional factors have been implicated in the complex aetiology of neural tube defects (NTD). We investigated whether the amount of weight a woman gained during pregnancy was associated with her risk of delivering an infant with an NTD.We conducted a population-based case-control study within the cohort of 708 129 live births and fetal deaths occurring in selected California counties in 1989-1991. Face-to-face interviews were conducted with mothers of 538 (88% of eligible) NTD cases (including those electively terminated, stillborn, or liveborn) and with mothers of 539 (88%) non-malformed liveborn controls within an average of 5 months from the term delivery date. Respondent-reported weight gain during pregnancy (kg) was analysed. Risks of infants having NTD were estimated among women who gained <10 kg compared to those who gained > or =10 kg during > or =38 week gestations.Compared to women who gained > or =10 kg, an increased risk for NTD offspring was observed among women who gained <10 kg (odds ratio [OR] = 3.2, 95% CI : 2.3-4.6). The OR was 5.0 (95% CI : 2.6-9.7) among those women who gained <5 kg during pregnancy. The increased risk was not attributable to maternal non-use of a multivitamin containing folic acid, diabetes, NTD-pregnancy history, age, race/ethnicity, education, gravidity, alcohol use, cigarette use, prepregnant obesity, low socioeconomic status, dieting, nausea, nor to lower dietary intakes of folate, zinc, energy, protein, fat, carbohydrates, and methionine. An increased risk was observed even after simultaneous adjustment for most of these factors (OR = 2.2, 95% CI : 1.2-3.8). The risk associated with gaining <10 kg was greater for anencephaly, but still elevated for spina bifida.We did not have information on weight gain during early pregnancy. Because weight gain during the relevant embryological period for NTD (first month post-conception) is relatively small and often variable, it seems less likely that elevated NTD risks indicate a causal association between lowered weight gain throughout pregnancy and abnormal development of the neural tube. It seems more likely that lowered weight gain is a consequence of carrying an NTD-affected fetus. However, what this consequence is and why risk was substantially larger for anencephaly is unknown.
View details for Web of Science ID 000167587300019
View details for PubMedID 11171858
Numerous studies have reported reduced risks for a variety of single congenital anomaly phenotypes associated with maternal periconceptional use of vitamin supplements containing folic acid. Here we investigated whether periconceptional use of vitamin supplements containing folic acid by women altered their risk for delivering infants with multiple congenital anomalies (MCAs). Data were derived from a case-control study representing deliveries (fetal deaths and infants) from 2 California counties between January 1993 and July 1996. MCAs were defined as 2 or more congenital anomalies affecting more than one organ system or a major anomaly in combination with 2 minor anomalies. Controls were randomly selected from nonmalformed live-born infants. Telephone interviews were conducted with 112 (73.7% of eligible) case and 195 (78.0% of eligible) control mothers. Compared to women who did not use multivitamin supplements containing folic acid in the period 3 months before through 3 months after conception, women who used in this time period were observed to have an elevated risk to deliver fetuses or infants with MCAs, odds ratio = 2.6 (95% confidence interval 1.1-6.2). This elevated risk was not substantially altered (adjusted odds ratio = 2.9 [0.8-10.3]) by adjusting for maternal race/ethnicity, education, gravidity, body mass index, alcohol consumption, and cigarette smoking. No particular organ system seemed to be uniquely represented among the MCA fetuses and infants whose mothers used vitamin supplements. The observed elevated risk associated with maternal vitamin use is considered to be preliminary and needs to be replicated in other populations.
View details for Web of Science ID 000087965900005
View details for PubMedID 10925379
Previous studies have observed an increased risk of approximately twofold or more for neural tube defects (NTD) associated with maternal obesity before pregnancy based on a body mass index (BMI) of > 29 kg/m2. No additional maternal factor appeared substantially to influence this association. Here, we explore further the association between BMI and NTD risk by considering the separate contributions of maternal prepregnant BMI and height. We also explore whether selected congenital anomalies, in addition to NTDs, were associated with maternal height or prepregnant BMI. Data were derived from two California population-based case-control studies. One study comprised 538 NTD cases and 539 non-malformed control infants. The other study included an additional 265 NTD cases, as well as 207 conotruncal cases, 165 limb anomaly cases, 662 orofacial cleft cases and 734 non-malformed controls. Maternal interviews in both studies elicited information on maternal height and prepregnant weight. Anomaly risk was described using additive linear logistic regression models. Results revealed increasing NTD risk with increasing maternal prepregnant BMI, controlling for maternal height. These patterns were observed overall as well as for most race/ethnic groups. Increasing NTD risk for decreasing height controlling for maternal BMI was also observed in one NTD study, but was not as evident in the other. Elevated risks for increasing maternal BMI and decreasing maternal height were not observed consistently for the other studied anomalies. The mechanisms underlying the association between maternal weight, or possibly maternal height, and NTD-affected pregnancy risk are unknown. Exploration of other data sets will be needed to determine whether similar patterns of NTD risk or lack of risk for other anomalies are associated with the two maternal anthropometric variables, height and prepregnant weight.
View details for Web of Science ID 000088859700007
View details for PubMedID 10949215
A twofold or greater risk of neural tube defect (NTD)-affected pregnancy has been associated with prepregnant obesity, where obesity was defined as body mass index (BMI) of >29 kg/m(2). Risks have been more elevated for spina bifida than for anencephaly.We investigated whether finer phenotypic classifications of spina bifida, in combination with other factors, were associated with a BMI of >29 kg/m(2). Data were derived from a case-control study of fetuses and infants with NTDs among 1989-1991 California births. Interviews were conducted with mothers of 277 spina bifida cases and 517 nonmalformed controls.Women with a BMI of >29 kg/m(2) compared with those =29 kg/m(2) revealed an odds ratio (OR) of 2.2 (95% confidence interval [95% CI] = 1.4-3. 3) for spina bifida in their infants and fetuses. Elevated risks were observed for each spina bifida subphenotype, and risks varied by subphenotype: open spina bifida, OR = 2.0 (1.2-3.1); closed (skin-covered), 3.3 (1.4-7.5); isolated, 2.2 (1.4-3.4); nonisolated, 1.9 (0.9-4.2); high, 4.5 (2.1-9.6); low, 1.9 (1.2-2.9); open/isolated/high, 7.1 (2.8-18.1); and open/isolated/low, 1.8 (1. 1-3.1). Risks were higher among female infants/fetuses and foreign-born Latinas, and for some phenotypes the risks were quite large, e.g., OR = 8.3 (2.9-23.6) for "closed" spina bifida among female infants/fetuses whose mothers were >29 kg/m(2) compared with males whose mothers were =29 kg/m(2). Maternal periconceptional vitamin use was not observed to influence risk as greatly across phenotypes.The observed pathogenetic heterogeneity of prepregnant obesity and spina bifida risks suggests that there are likely to be several biologic mechanisms underlying the association.
View details for Web of Science ID 000086815900009
View details for PubMedID 10777833
Several recent studies have observed an association between neural tube defect risk and prepregnant obesity. This association was generally stronger for spina bifida and was observed irrespective of additional maternal factors, including periconceptional intake of vitamin supplements. Other studies have identified mutations within the genes that code for leptin (LEP) and its receptor (LEPR), which have been linked to obesity in mice and humans. We investigated the potential association between nucleotide variation at the LEP and LEPR loci, and increased risk of spina bifida. We searched specifically for allelic association at a pair of highly polymorphic microsatellites closely linked to either the LEP or LEPR gene. Data were derived from a population-based case-control study that had previously identified an association between a woman's prepregnant obesity and her risk of delivering an infant with spina bifida. A total of 56 spina bifida case infants and 126 nonmalformed control infants were genotyped for 10 microsatellite alleles closely linked to the LEP gene, and 49 cases and 125 controls were genotyped for 10 microsatellite alleles closely linked to the LEPR gene. In general, alleles were not observed to be exclusively associated with substantially greater spina bifida risk in the body mass index (BMI) category (obese) of >29 kg/m(2) compared with the BMI category (nonobese) of =29 kg/m(2). Thus, these particular infant allelic variants did not appear to explain the previously reported elevated risk observed for women whose prepregnant BMI exceeded 29 kg/m(2). A modest elevated spina bifida risk, irrespective of maternal BMI, was observed for two LEP microsatellite alleles (257 and 271). These estimates, however, were imprecise. Compared with those infants who did not have either of these alleles and whose mother's prepregnant BMI was =29 kg/m(2), we computed odds ratios for (1) having either the 257 or 271 allele and maternal BMI >29 kg/m; (2) having either allele and BMI =29 kg/m(2); and (3) not having either allele but BMI >29 kg/m(2). The odds ratios (95% confidence interval) for these comparisons were: for allele 257, 4.5 (1.1-19.4), 1.9 (0.5-6.3), and 2.9 (1.3-6.4), respectively, and for allele 271, 6.7 (1.6-30.4), 2.7 (0.7-10.9), and 2.7 (1.2-5.9), respectively. Owing to the exploratory nature of this investigation, the significance of these latter results is unclear.
View details for Web of Science ID 000085525700011
View details for PubMedID 10661913
Holoprosencephaly is a developmental field defect manifested by a spectrum of abnormalities of the forebrain and midface. Approximately 50% of holoprosencephaly cases are associated with a cytogenetic abnormality or a monogenic syndrome. Suggested risk factors for the remaining 50% of cases have been described in case reports, but have not been confirmed in systematically conducted studies. We report the results of a population-based case-control study of holoprosencephaly. Live births, fetal deaths, and terminations with a diagnosis of cytogenetically normal holoprosencephaly were identified by the California Birth Defects Monitoring Program. Telephone interviews were conducted with the mothers of 58 cases and 107 live born, nonmalformed controls. Women were questioned about their health and reproductive histories, family demographics, and exposures occurring during their pregnancies. Among nonsyndromic cases, increased risks were observed for females (OR=1.8, 95% C.I. 0.9-3.9), foreign-born vs. U.S. or Mexico-born women (OR=3.1, 95% C.I. 1.1-8.6), and women with early menarche (OR=2.3, 95% C.I. 0.9-5.7). Maternal periconceptional exposures associated with increased risks for nonsyndromic holoprosencephaly included alcohol consumption (OR=2.0, 95% C.I. 0.9-4.5), cigarette smoking (OR=4.1, 95% C.I. 1.4-12.0), and combined alcohol and smoking (OR=5.4, 95% C.I. 1.4-20.0), insulin-dependent diabetes (OR=10.2, 95% C.I. 1.9-39.4), medications for respiratory illnesses (OR=2.3, 95% C.I. 0.9-6.0), and salicylate-containing medications (OR=2.5, 95% C.I. 0.8-7.9). These findings are consistent with risk factors identified in some previous reports, and identify several new potential risk factors that require confirmation in future studies.
View details for Web of Science ID 000085166200011
View details for PubMedID 10710231
We used data from a population-based case-control study to explore the relation between certain life events during the periconceptional period and several types of congenital anomalies. We ascertained cases from pregnancies ending in 1987-1989 and randomly selected controls from eligible liveborn infants. In telephone interviews, women reported deaths of anyone close to them. They also reported job losses or separations/divorces, for themselves or anyone close to them. Experiencing at least one stressful event during the periconceptional period was associated with a prevalence odds ratio of 1.4-1.5 for the delivery of infants with conotruncal heart defects, neural tube defects, and isolated cleft lip with or without palate. These associations tended to be restricted to women who were not obese and women with less than or equal to a high school education. This study suggests that women who experience stressful life events around the time of conception or early gestation may be at increased risk of delivering infants with certain congenital anomalies.
View details for Web of Science ID 000084316000008
View details for PubMedID 10615840
Evidence for the teratogenicity of corticosteroids in humans is limited and has resulted in inconsistent recommendations regarding their use during early pregnancy. We examined the association between women's corticosteroid use during the periconceptional period (1 month before to 3 months after conception) and delivering infants with selected congenital anomalies. Data were derived from a population-based case-control study that included cases of orafacial clefts (n = 662), conotruncal heart defects (n = 207), neural tube defects (n = 265), and limb reduction defects (n = 165). Information on medication use was collected via maternal telephone interviews. Corticosteroid use was associated with an increased risk for isolated cleft lip with or without cleft palate (odds ratio 4.3, 95% confidence interval 1.1-17.2) and isolated cleft palate (odds ratio 5.3, 95% confidence interval 1.1-26.5). Increased risks were not observed for the other anomaly groups studied. These data in conjunction with other epidemiologic data suggest a possible causal association between cleft lip and palate and corticosteroid use.
View details for Web of Science ID 000082714300009
View details for PubMedID 10482873
The authors investigated the association between maternal preconceptional supplemental and dietary zinc intake and risk of neural tube defects (NTDs) in a population-based case-control study conducted between 1989 and 1991 in California. Cases were 430 NTD-affected fetuses/infants, and controls were 429 randomly selected non-malformed infants. Mothers reported their preconceptional use of vitamin, mineral, and food supplements, and completed a 98-item food frequency questionnaire. Increased total preconceptional zinc intake was associated with a reduced risk for NTDs (quintile 5 vs. quintile 1, odds ratio (OR) = 0.65, 95% confidence interval (CI) 0.43, 0.99). Phytate intake, a constituent of the diet known to impede zinc absorption, appeared to modify the zinc - NTD association. In addition, increased servings of animal products, the most bioavailable food source of zinc, was associated with a reduced risk for NTDs (quintile 5 vs. quintile 1, OR = 0.49, 95% CI 0.32, 0.76). Risk estimates for zinc intake were changed little after controlling for multiple sociodemographic factors and total folate intake, but were attenuated after controlling for nutrients highly correlated with dietary sources of zinc, such as protein. In sum, the analyses indicate that risk of NTDs in infants and fetuses decreased with increasing maternal preconceptional zinc intake. However, it remains unclear whether increased zinc intake, or another nutrient or combination of nutrients highly correlated with zinc intake in the diet, is causally associated with reduced NTD risk.
View details for Web of Science ID 000082602300009
View details for PubMedID 10490000
Electric and magnetic fields are of concern as risk factors for adverse reproductive outcomes, including congenital anomalies. Among residential exposures to electric and magnetic fields, electric bed-heating devices such as electric blankets may be a substantial source of such exposures, and their use is fairly common. Two population-based case-control studies were analyzed to investigate whether the periconceptional use of electric blankets, bed warmers, or electrically heated waterbeds increased the risk of women to deliver infants or fetuses with neural tube defects (NTDs) or orofacial clefts. We obtained information on bed-heating devices from 538 NTD cases and their 539 controls in one study, and 265 NTD cases and 481 controls and 652 orofacial cleft cases and their 734 controls from another study. Our results revealed a few modestly elevated risks of certain anomaly phenotypes with maternal use of certain bed-heating devices, but risks tended to be imprecise. In general, women who reported more frequent use of a bed-heating device, or longer duration of use, did not appear to have a higher risk for delivering offspring with anomalies than were women who reported less frequent or shorter-duration use.
View details for Web of Science ID 000082421200006
View details for PubMedID 10471895
This population-based study examined the effect of all major congenital anomalies on the mortality of White and Black infants by infant sex, birthweight, gestational age, and lethality of the anomaly. The study also determined the total contribution of anomalies to infant mortality.California Birth Defects Monitoring Program data were merged with linked birth-death files for 278,646 singleton non-Hispanic White and Black infants born in 1983 through 1986. Malformed infants were compared with nonmalformed infants to determine the effect of anomalies on mortality.The presence of any congenital anomaly increased mortality 9.0-fold (95% CI = 7.3, 11.1) for Black infants and 17.8-fold (95% CI = 16.2, 19.6) for White infants. Even "non-lethal" anomalies increased mortality up to 8.9-fold. Overall, anomalies contributed to 33% of White infant deaths, to 19% of Black infant deaths, and to over 60% of deaths among Black and White neonates weighing over 1499 g.The contribution of congenital anomalies to mortality of both low- (< 2500 g) and normal-birth-weight infants is substantially higher than previously estimated, representing a large public health problem for both Black and White infants.
View details for Web of Science ID 000080548000015
View details for PubMedID 10358680
To investigate whether periconceptional maternal alcohol consumption increased the risk of delivering infants with orofacial cleft phenotypes.Data were derived from a large population-based case control study of fetuses and infants among a cohort of California births from 1987 to 1989 (n = 548,844). Information concerning alcohol consumption was obtained by telephone interviews with mothers of 731 infants (84.7% of eligible) with orofacial clefts and of 734 (78.2%) infants in a nonmalformed control group.Thirty-nine percent of mothers in the case group and 42% of mothers in the control group reported that they consumed alcohol during the period 1 month before through 3 months after conception. Relative to nonconsumers, women who reported alcohol consumption (
View details for Web of Science ID 000078985800011
View details for PubMedID 10064665
In a case-control study, we investigated whether occupational and nonoccupational (hobbies) chemical exposures to women in the periconceptional period increased their risk for having neural tube defect-affected pregnancies. Women were asked about occupational tasks and hobbies performed during the 3 months before through 3 months after conception. Based on her reported occupational tasks and hobbies, an industrial hygienist assigned a priori defined exposure categories to each task and hobby. The exposure categories included 74 chemical groups, 9 "end-use" chemical groups, and organic solvents. Face-to-face interviews were conducted with mothers of 538 (88% of eligible) infants or fetuses with neural tube defect and mothers of 539 (88%) randomly selected, nonmalformed, live-born infants from a population-based 1989-1991 cohort of California births (N = 703,518). Our results suggested that maternal exposures in the periconceptional period to a variety of chemicals associated with occupational and nonoccupational activities did not contribute substantially to risk of neural tube defects in offspring. We observed no effect estimate greater than 2.0 for maternal exposures to the chemical agent groups studied. We did not observe substantially elevated risks associated with maternal exposures to any of the end-use chemical groups or to organic solvents. Considering occupational exposures only among women who worked did not substantially alter results. Adjustment for maternal vitamin use, race/ethnicity, or education level also did not substantially alter the observed associations.
View details for Web of Science ID 000078746100007
View details for PubMedID 10069246
We explored the relation between various potential sources of maternal periconceptional pregnancy exposures to pesticides and congenital anomalies in offspring. Data were derived from a case-control study of fetuses and liveborn infants with orofacial clefts, neural tube defects, conotruncal defects, or limb anomalies, among 1987-1989 California births and fetal deaths. We conducted telephone interviews with mothers of 662 (85% of eligible) orofacial cleft cases, 265 (84%) neural tube defect cases, 207 (87%) conotruncal defect cases, 165 (84%) limb cases, and 734 (78%) nonmalformed controls. The odds ratio (OR) estimates did not indicate increased risk for any of the studied anomaly groups among women whose self-reported occupational tasks were considered by an industrial hygienist likely to involve pesticide exposures. Paternal occupational exposure to pesticides, as reported by the mother, revealed elevated ORs for only two of the cleft phenotypes [OR = 1.7 [95% confidence interval (CI) = 0.9-3.4] for multiple cleft lip with/without cleft palate and OR = 1.6 [95% CI = 0.7-3.4] for multiple cleft palate]. Use of pesticide products for household gardening, by mothers or by professional applicators, was associated with ORs > or =1.5 for most of the studied anomalies. Use of pesticide products for the control of pests in or around homes was not associated with elevated risks for most of the studied anomalies, although women who reported that a professional applied pesticides to their homes had increased risks for neural tube defect-affected pregnancies [OR = 1.6 (95% CI = 1.1-2.5)] and limb anomalies [OR = 1.6 (95% CI = 1.0-2.7)]. Having a pet cat or dog and treating its fleas was not associated with increased anomaly risk. Women who reported living within 0.25 miles of an agricultural crop revealed increased risks for offspring with neural tube defects [OR = 1.5 (95%CI = 1.1-2.1)]. For many of the comparisons, data were sparse, resulting in imprecise effect estimation. Despite our investigating multiple sources of potential pesticide exposures, without more specific information on chemical and level of exposure, we could not adequately discriminate whether the observed effects are valid, whether biased exposure reporting contributed to the observed elevated risks, or whether nonspecific measurement of exposure was responsible for many of the observed estimated risks not being elevated.
View details for Web of Science ID 000077715100011
View details for PubMedID 9888281
Studies have reported an association between homozygosity for a variant form of the methylenetetrahydrofolate reductase (MTHFR) gene and risk for neural tube defects. Because of MTHFR's involvement with folate metabolism and evidence that maternal use of a multivitamin with folic acid in early pregnancy reduces risk for cleft lip with or without cleft palate (CLP), we hypothesized that infants homozygous for the C677T genotype would be at increased risk for CLP because of lower MTHFR enzymatic activity. Data were derived from a large population-based, case-control study of fetuses and liveborn infants among a cohort of 1987 to 1989 California births. The analyses involved 310 infants with isolated CLP whose mothers completed a telephone interview and whose DNA was available from newborn screening blood specimens and involved 383 control infants without a congenital anomaly whose mothers completed a telephone interview and whose DNA was available. Cases and controls were genotyped TT if homozygous for the C677T allele, CT if heterozygous for the C677T allele, and CC if homozygous for the C677 (wild-type) allele. Odds ratios for CLP were 0.89 (0.55 to 1.4) and 0.78 (0.56 to 1.1) for infants with TT versus CC and infants with CT versus CC genotypes, respectively. Compared with the CC genotype, the odds ratios for CLP among infants with the TT genotype were 0.74 (0.39 to 1.4) for those infants whose mothers were users and 1.4 (0.54 to 3.6) for those infants whose mothers were not users of multivitamins containing folic acid periconceptionally. The two estimates were not statistically heterogeneous (P = 0.30). Our results did not indicate increased risks for CLP among infants homozygous for the C677T genotype, nor do they indicate an interaction between infant C677T genotype and maternal multivitamin use on the occurrence of CLP.
View details for Web of Science ID 000077117700002
View details for PubMedID 9843036
This study evaluated the contributions of lower socioeconomic status (SES) and neighborhood socioeconomic characteristics to neural tube defect etiology. The influence of additional factors, including periconceptional multivitamin use and race/ethnicity, was also explored.Data derived from a case-control study of California pregnancies from 1989 to 1991. Mothers of 538 (87.8% of eligible) case infants/fetuses with neural tube defects and mothers of 539 (88.2%) nonmalformed infants were interviewed about their SES. Reported addresses were linked to 1990 US census information to characterize neighborhoods.Twofold elevated risks were observed for several SES indicators. Risks were somewhat confounded by vitamin use, race/ethnicity, age, body mass index, and fever but remained elevated after adjustment. A risk gradient was seen with increasing number of lower SES indicators. Women with 1 to 3 and 4 to 6 lower SES indicators had adjusted odds ratios of 1.6 (1.1-2.2) and 3.2 (1.9-5.4), respectively, compared with women with no lower SES indicators.Both lower SES and residence in a SES-lower neighborhood increased the risk of an neural tube defect-affected pregnancy, with risks increasing across a gradient of SES indicators.
View details for Web of Science ID 000076694100014
View details for PubMedID 9807535
To investigate variations in the prevalence of oral cleft anomalies according to parental race and ethnicity and maternal country of birth, the authors analyzed a cohort of 2,221,755 live births and fetal deaths delivered between 1983 and 1992 to residents of California. A total of 2,329 cleft lip with or without cleft palate (CL +/- P) cases and 1,475 cleft palate alone (CP) cases were identified by the California Birth Defects Monitoring Program, a population-based registry. Compared to Whites, the prevalence of CL +/- P was lower among African Americans (prevalence ratio (PR) = 0.56, 95% confidence interval (CI) = 0.45-0.69), higher among Native Americans (PR = 1.81, CI = 1.20-2.69), and the same among the Japanese (PR = 1.07, CI = 0.62-1.82) and Chinese (PR = 0.96, CI = 0.71-1.29). The risk of CL +/- P was slightly lower among the offspring of foreign-born Chinese women relative to U.S.-born Chinese women (PR = 0.71, CI = 0.33-1.57), and slightly higher among foreign-born Filipinos relative to their U.S.-born counterparts (PR = 1.37, CI = 0.57-3.53), although confidence intervals around these risk estimates were wide owing to sparse data. For CP, lower prevalences were observed among African Americans (PR = 0.72, CI = 0.58-0.91) and Hispanics (PR = 0.77, CI = 0.67-0.87) than among Whites. The risk of CP was higher among foreign-born Filipinos compared to U.S.-born Filipinos (PR = 1.52, CI = 0.58-4.33), although the confidence interval around this estimate included unity. These prevalence variations may reflect differences in both environmental and genetic factors affecting clefting risk.
View details for Web of Science ID 000075620300011
View details for PubMedID 9738868
To describe the health practices and energy and nutrient intakes from diet and supplements of foreign- and US-born Latinas and white non-Latinas in the 3 months before pregnancy.A descriptive study in which data were obtained retrospectively from 2 questionnaires: an interviewer-administered questionnaire on the subject's medical, reproductive, family, occupational, and lifestyle history and a subject-administered (and interviewer-assisted) 100-item food frequency questionnaire.A population-based sample of California women (n = 462) who gave birth between 1989 and 1991 to single, live-born infants. One third of women were Latinas, of whom 58.1% were foreign born.Means, standard deviations, and percentiles were computed for energy and nutrient intakes of the total population and for white non-Latinas; US-born Latinas; and foreign-born Latinas. One-way analysis of variance was used to compare group means.Mean and median energy intake in all ethnic groups exceeded 2,000 kcal/day, although less than half of the population consumed 5 servings of fruit and vegetables per day. For iron, half of the women were below the Recommended Dietary Allowance. In contrast to the dietary intake of white non-Latinas and US-born Latinas, foreign-born Latinas had the lowest contribution of fat to total energy intake and the highest dietary intake of carbohydrate, cholesterol, fiber, grain products, protein foods, folate, vitamin C, iron, and zinc.A woman's ethnicity, as well as whether her place of birth was within or outside of the United States, may be predictors of her dietary and health practices before pregnancy. Vitamin, mineral, and food supplementation and consumption of cold breakfast cereal may be avenues for improving perinatal micronutrient intake.
View details for Web of Science ID 000075215700018
View details for PubMedID 9710657
Maternal periconceptional use of vitamin supplements containing folic acid substantially reduces the risk of neural tube defects (NTDs) in the offspring. The mechanism underlying this reduction in risk is unknown. Several recent studies have reported an association between homozygosity for a variant form (the C677T genotype) of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and risk for NTDs in individuals. It has been hypothesized that maternal folic acid supplementation prevents NTDs by partially correcting reduced MTHFR activity associated with the variant form of the enzyme. Using data from two California case-control interview studies (1987-1991 birth cohorts), the authors investigated whether an interaction for spina bifida risk existed between infant MTHFR C677T genotype and maternal use of supplements containing folic acid. The authors genotyped the allelic variants of MTHFR in 214 liveborn case infants with spina bifida and 503 control infants for whom information on maternal periconceptional vitamin use was available. The percentage of all case infants with the C677T MTHFR mutation, for both homozygous (TT) and heterozygous (TC) genotypes, was slightly higher than that of controls. The C677T genotype was substantially more frequent among both case and control Hispanic infants than among non-Hispanic infants. Among all infants whose mothers did not periconceptionally use vitamins containing folic acid, the risk of spina bifida, as measured by the odds ratio, was 1.6 (95% confidence interval (CI) 0.8-3.1) for all infants with the TT genotype and 2.0 (95% CI 0.5-7.4) for non-Hispanic white infants with the TT genotype, as compared with infants with the CC genotype. This result indicates a modestly increased risk associated with the C677T genotype. A lower risk estimate (odds ratio=1.2, 95% CI 0.4-4.0) was observed among infants whose mothers periconceptionally used vitamin supplements containing folic acid. This population-based California study found a modestly increased risk of spina bifida among infants who were homozygous for the C677T genotype, but only minimal evidence of an interaction between the C677T genotype and maternal folic acid intake in the occurrence of spina bifida. If this mutant MTHFR genotype plays a role in the association between maternal vitamin use and NTD risk, it may be a small role, or it may be conditional on maternal genotype.
View details for Web of Science ID 000074710300006
View details for PubMedID 9663401
We previously demonstrated a strong association between periconceptional maternal cigarette smoking, infant transforming growth factor-alpha (TGFa) genotype, and risk of orofacial clefts. Because serum folate may be decreased by cigarette smoking and because maternal periconceptional use of multivitamins containing folic acid has been associated with a reduced risk of clefting, we explored whether a potential relation existed between infant TGFa genotype, maternal multivitamin use, and risk of orofacial cleft phenotypes.Data were derived from a population-based case-control study of fetuses and live-born infants among a cohort of 1987 to 1989 California births (n = 548,844). Information concerning periconceptional multivitamin use was obtained via telephone interviews with mothers of 731 (84.7% of eligible) orofacial cleft case infants, and of 734 (78.2%) nonmalformed control infants. DNA was obtained from newborn screening bloodspots and genotyped for the Taql polymorphism of TGFa. Among infants of interviewed mothers, genotypes were available for 571 (78.1%) case infants and 640 (87.2%) control infants.The study encompassed all hospitals in selected California counties.The main outcome measures were the risks of specific cleft phenotypes among infants with uncommon TGFa genotypes and whose mothers did not use multivitamins periconceptionally.Compared with infants homozygous for the common TGFa genotype and whose mothers used multivitamins, increased clefting risks were observed for infants with the A2 genotype (homozygous or heterozygous) and whose mothers did not use multivitamins. Risk estimates were 3.0 (1.4-6.6 [95% confidence interval]) for isolated cleft lip with or without cleft palate (CLP), 2.4 (0.69-11.6) for multiple CLP, 2.6 (0.97-7.7) for isolated cleft palate (CP), 4.2 (1.3-16.2) for multiple CP, and 8.1 (2.6-27.7) for "known-syndrome" clefts. Clefting risks for infants with the A2 genotype and whose mothers used multivitamins were substantially smaller, as were the risks for infants with the A1 genotype whose mothers did not use multivitamins.These data provide preliminary evidence for a gene-nutrient interaction in risk of clefting.
View details for Web of Science ID 000075675900013
View details for PubMedID 9684776
Neural tube and orofacial defects are common congenital malformations in humans. While etiologically heterogeneous, they are for the most part multifactorial in their pathogenesis, having both genetic and environmental components in their development. In recent years, there has been a great deal of epidemiologic evidence demonstrating that women who received multivitamins containing folic acid periconceptionally had significantly reduced occurrence and recurrence risks for producing infants with such malformations. This risk reduction is not observed in all populations, further suggestive of a genetic regulation of this phenomenon. Unfortunately, the mechanisms underlying the beneficial effects of folic acid are not well-understood. In this article, we review the relevant epidemiologic data on both neural tube defects and orofacial malformations, the fundamental embryological processes involved in closing the neural tube, and the development of the craniofacies, and propose a working hypothesis for susceptibility to these malformations. This hypothesis is based on the interworkings of cellular folate transport, focusing on the key elements involved in potocytosis. We propose that infants with mutations in the folate receptor alpha gene might be at increased risk for congenital anomalies due to a reduced binding affinity for 5-methyltetrahydrofolate, the physiologic form of folic acid. Various experimental approaches to test the working hypothesis are considered.
View details for Web of Science ID 000071886700003
View details for PubMedID 9488247
Results from experimental animals and other laboratory data have suggested a role for methionine, an essential amino acid, in normal closure of the neural tube. We hypothesized that women who had higher dietary intakes of methionine would be at lower risk for neural tube defect (NTD)-affected pregnancies. Data were derived from a population-based case-control study of fetuses and liveborn infants with NTDs among a 1989-1991 California birth cohort. Interviews, which included a 100-item food frequency questionnaire, were conducted with mothers of 424 NTD cases and 440 nonmalformed controls. Risk for having an NTD-affected pregnancy was estimated according to quartiles (established from intakes among control mothers) of average daily maternal dietary intake of methionine in the 3 months before conception. We observed an approximately 30-40% reduction in NTD-affected pregnancies among women whose average daily dietary intake of methionine was above the lowest quartile of intake (> 1,341.86 mg/ day). These reductions in NTD risk were observed for both anencephaly and spina bifida; remained after adjustment for maternal race/ethnicity and education; and were observed irrespective of maternal level of folate intake. Although we were unable to establish whether the observed reductions in NTD risk were attributable to maternal periconceptional methionine intake or to another highly correlated nutrient, these data add to the growing body of evidence that maternal diet plays a role in neural tube closure.
View details for Web of Science ID 000071353300001
View details for PubMedID 9451752
This study investigated a previously reported 50% or more increased risk for neural tube defect-affected pregnancies among Latina women compared with White women.Data were derived from a population-based case-control study of fetuses and live-born infants with neural tube defects in a 1989-through-1991 California birth cohort. Interviews were conducted with mothers of 538 (88% of eligible) infants/fetuses with neural tube defects and mothers of 539 (88%) nonmalformed control infants.The risk for a neural tube defect-affected pregnancy was approximately twice as high among women of Mexican descent than among White women (odds ratio = 1.9, 95% confidence interval [CI] = 1.5, 2.8). The odds ratio for Mexico-born Mexican women compared with White women was 2.4 (95% CI = 1.7, 3.2), whereas the risk for US-born women of Mexican and other racial/ethnic descent was not substantially higher than that for Whites. The higher risk among Mexico-born Mexican women was not attributable to differences in numerous studied parental characteristics and exposures.Given that nearly 20% of all California births are to Mexico-born Mexican women, the increased risks observed are relevant to the population burden of neural tube defects.
View details for Web of Science ID A1997XY23500012
View details for PubMedID 9314798
It is well established that maternal multivitamin supplementation reduces the risk of neural tube defects and evidence suggests that it may be associated with other reproductive outcomes. The present study was prompted by a report from a randomized trial in Hungary which showed a 40% increase in multiple births among periconceptional vitamin users. Retrospectively collected data on multivitamin supplementation were obtained on multiple and singleton births from three separate studies: Atlanta Birth Defects Case-Control Study (ABDCCS) malformed and nonmalformed infants born 1968-1980, California Birth Defects Monitoring Program (CBDMP) malformed and nonmalformed infants born 1987-1989, and Boston University Slone Epidemiology Unit Birth Defects Study (SEU-BDS) malformed infants born 1987-1994. Supplementation was divided into three mutually exclusive categories based on timing: "periconceptional" use--before through at least the third month after conception; "early" use--beginning in the first month and continuing through at least the third month after conception; and "later" use--beginning in the second or third month after conception. For periconceptional use, four of five datasets showed a 30 to 60% greater prevalence of supplementation among mothers of multiple births. In contrast, this pattern was not evident for "early" and "later" use. Overall, the study findings are tentative, due to a lack of consistency across all five datasets and they should not alter recent recommendations related to folate supplementation for the prevention of neural tube defects.
View details for Web of Science ID A1997XG44200017
View details for PubMedID 9215776
Using data from two population-based case-control studies, we investigated whether maternal residential proximity to hazardous waste sites increased the risk for neural tube defects, conotruncal heart defects, and oral cleft defects in California. We obtained a residential history by interview for mothers of 507 neural tube defect cases (82.7% of eligible) and their 517 controls (84.6%); and 201 heart cases (84.4%), 439 cleft cases (82.2%), and their 455 controls (72.1%). We identified the locations of 764 inactive hazardous waste sites and systematically collected information on site-related contamination for the subset of 105 National Priority List sites. After controlling for several potential confounders, we found little or no increased risk for maternal residence in a census tract containing a site [odds ratio (OR) = 0.9, 95% confidence interval (CI) = 0.7-1.3 for neural tube defects; OR = 1.3, 95% CI = 0.8-2.1 for heart cases; OR = 1.2, 95% CI = 0.8-1.8 for clefts], but elevated risks for neural tube defects (OR = 2.1, 95% CI = 0.6-7.6) and heart defects (OR = 4.2, 95% CI = 0.7-26.5) for maternal residence within 1/4 mile of a National Priority List site. Furthermore, we observed elevated ORs (> or = 2.0) for neural tube defects and heart defects in association with maternal residence within 1 mile of National Priority List sites containing selected chemical contaminants. Among controls, only 0.6% and 4.4% lived within 1/4 mile and 1 mile of a National Priority List site, respectively, resulting in imprecision in risk estimation.
View details for Web of Science ID A1997XG00500005
View details for PubMedID 9209846
Epidemiologic studies of congenital anomalies rarely incorporate measurements of both environmental and genetic factors. Given the suspected etiologic heterogeneity that exists among congenital anomalies, focusing on only environmental or on only genetic factors may substantially decrease the likelihood for identifying either type of factor as a contributor to the risk of congenital anomalies. Incorporating information on genotypic variation into an epidemiologic study of environmental exposures may potentially lead to improvements in case classification with accompanying potential improvements in risk estimation. Such genotypic information may also lead to a clearer understanding of the underlying pathogenesis and etiology of congenital anomalies. Using recent research findings on congenital anomalies, we illustrated the issues of case classification and how a clearer impression of the underlying pathogenesis can be achieved with the addition of genotypic information to epidemiologic studies of congenital anomalies.
View details for Web of Science ID A1997WQ84000016
View details for PubMedID 9100302
The authors investigated whether maternal or paternal periconceptional use of recreational drugs increased the risk of having neural tube defect (NTD)-affected pregnancies using a population-based case-control study of fetuses and liveborn infants with NTDs among 1989-1991 California births. Face-to-face interviews were conducted with mothers of 538 (88% of eligible) NTD cases and 539 (88%) nonmalformed controls, usually within 5 months of delivery. Periconceptional maternal use of cocaine (odds ratio (OR) = 0.74, 95% confidence interval (CI) 0.40-1.4), amphetamines/speed (OR = 0.68, 95% CI 0.39-1.2), or marijuana (OR = 0.64, 95% CI 0.43-0.95) or preconceptional use of alcohol as < 1 drink/day (OR = 0.80, 95% CI 0.62-1.0) or > or = 1 drink/day (OR = 0.69, 95% CI 0.42-1.2) or of cigarettes as < 1 pack/day (OR = 0.90, 95% CI 0.65-1.2) or > or = 1 pack/day (OR = 0.59, 95% CI 0.36-0.96) did not increase the risk for delivering NTD-affected offspring. Risks were not substantially altered after adjustment for maternal age, race/ethnicity, vitamin use, education, and household income. Increased NTD risk was also not generally associated with paternal drug use. The authors could not discern whether the decreased risks observed for these maternal exposures reflected a true association or were due to reporting bias, a disproportionate number of drug-exposed NTD cases among spontaneous abortuses that could not be ascertained, or some other bias.
View details for Web of Science ID A1996VX62500009
View details for PubMedID 8956628
The authors examined the impact of prenatal diagnosis and elective termination of neural tube defect (NTD)-affected pregnancies on NTD prevalence and risk estimates. Prevalence data were actively ascertained and were derived from a population-based 1989-1991 cohort of California births. Included were 664 singleton infants/fetuses with an NTD. The birth prevalence (livebirths and stillbirths only) was 48.4% of the total prevalence (including elective terminations) for anencephaly and 70.2% for spina bifida. The authors also used in-person interview data from mothers of 538 of the ascertained NTD cases and mothers of 539 randomly selected nonmalformed control infants to examine maternal/infant characteristics. Compared with women who delivered liveborn/stillborn infants with an NTD, women who electively terminated NTD-affected pregnancies were disproportionately white, were more highly educated, had higher incomes, and used vitamins containing folic acid more often. For factors associated with elective terminations, risk estimates appeared biased when only liveborn and stillborn infants were included among cases compared with analyses in which all clinically recognized NTD-affected pregnancies were included.
View details for Web of Science ID A1996VE90000006
View details for PubMedID 8781462
Holoprosencephaly is a brain defect resulting from incomplete cleavage of the embryonic forebrain. It involves forebrain and facial malformations that can range from mild to severe. The epidemiology of holoprosencephaly is largely unknown. Published prevalence estimates have been derived from clinic-based case series, and suggested risk factors for holoprosencephaly have been identified in case reports, without confirmation from systematically conducted population-based studies. Using data from a population-based birth defects registry in California, we describe the epidemiologic and clinical characteristics of cytogenetically and phenotypically distinct types of holoprosencephaly. A total of 121 cases was identified among a cohort of 1,035,386 live births and fetal deaths. The prevalence of holoprosencephaly was 1.2 per 10,000 births (95% confidence interval 1.0-1.4 per 10,000). Of all cases, 41% (50/121) had a chromosomal abnormality, most commonly Trisomy 13. Among the 71 cytogenetically apparently normal cases, 18 had recognizable syndromes and the remaining 53 were of unknown cause. Among the cytogenetically abnormal cases, females had a greater risk than males (odds ratio = 2.3,95% confidence interval [1.2, 4.4]). Among the cytogenetically normal cases, increased risks were observed among Hispanic whites (OR = 1.8 [0.9, 3.6]) and cases whose mother was born in Mexico (OR = 2.2 [1.0, 4.5]). Approximately 46% of all cases had alobar holoprosencephaly, the most severe form of the forebrain malformation. The facial phenotype did not strongly predict the severity of the brain defect; however, severity was inversely correlated with length of survival. This study is the first to present findings based on such a large population-based series of infants/fetuses affected by holoprosencephaly, and demonstrates the importance of investigating the component subgroups of this rare phenotype.
View details for Web of Science ID A1996VC48400004
View details for PubMedID 8862623
In this population-based case-control study, we explored the association of selected parental and infant characteristics from the birth certificates of children with conotruncal heart defects. We compared 252 cases to a random sample of 5,000 nonmalformed infants from a cohort of 341,839 California live births for 1987-1988. The prevalence of conotruncal defects was 0.732 per 1,000 total births. A decreased risk (OR = 0.55, 95% CI0.33-0.89) for delivering infants with conotruncal defects was found among mothers born in Mexico compared to mothers born in California. An increased risk was observed for Native American mothers compared to non-Hispanic whites (OR = 2.6, 95% CI 1.1-6.0). We also compared risks associated with the individual diagnoses that comprise the group of conotruncal defects. Only minor differences in risk estimates between the anatomic diagnoses were observed, lending support to the methodologic approach of using conotruncal defects as a single category of heart defects in etiologic investigations.
View details for Web of Science ID A1996VP64400008
View details for PubMedID 8910983
To investigate the risk for neural tube defect (NTD)-affected pregnancies among obese women (ie, women with a body mass index [BMI] > 29kg/m2) compared with women of average prepregnancy weight.Population-based case-control study.All hospitals in 55 of 58 counties in California.In-person interviews were conducted with mothers of 538 (88% of eligible) NTD cases (including fetuses and infants electively terminated, stillborn, or born alive) and with mothers of 539 nonmalformed controls (88%) within an average of 5 months from the term delivery date.The risk of an NTD-affected pregnancy among obese women.Compared with women whose BMI was less than or equal to 29 kg/m2, an increased risk for NTD-affected pregnancy was observed among obese women (odds ratio, 1.9; 95% confidence interval, 1.3 to 2.9). The increased risk was not attributable to maternal nonuse of a vitamin containing folic acid, diabetes, use of diet pills, lower dietary folate intake, or an NTD-pregnancy history. Adjustment for maternal age, education, gravidity, use of vitamins, and use of alcohol did not change the odds ratio. The risk associated with maternal obesity was greater for spina bifida and for other less prevalent NTDs than for anencephaly.Because as many as 10% of women may be obese periconceptionally, the observed twofold increased risk is relevant to the population burden of NTDs.
View details for Web of Science ID A1996UD02700025
View details for PubMedID 8601928
Risks for selected congenital anomalies from parental smoking were investigated in a case-control study in California. Mothers of 207 infants with conotruncal heart defects, 264 infants with neural tube defects, 178 infants with limb deficiencies, and 481 live born control infants delivered in 1987-1988 were interviewed by telephone. Modestly elevated risks were observed for conotruncal heart defects and limb deficiencies, associated primarily with both parents smoking. An odds ratio of 1.9 (95 percent confidence interval 1.2-3.1) was observed for conotruncal heart defects and an odds ratio of 1.7 (95% confidence interval 0.96-2.9) for limb deficiencies when both parents smoked compared to neither parent smoking. We did not observe increased risks associated with maternal smoking in the absence of paternal smoking, although an increased risk associated with paternal smoking in the absence of maternal smoking was observed for limb deficiencies in offspring. For conotruncal defects, the risks associated with parental smoking differed among race/ethnic groups. Parental smoking was not associated with increased risks for neural tube defects. Observed risks did not change substantially when adjusted for maternal vitamin use, alcohol use, and gravidity. Some heterogeneity in risk was observed for phenotypic case subgroups, but data were too sparse to draw firm inferences.
View details for Web of Science ID A1996VA37300010
View details for PubMedID 8864168
Several but not all studies indicate that chorionic villus sampling (CVS) is associated with an increased risk for transverse limb deficiencies, including digital deficiencies. It has been suggested that variations in results regarding the transverse digital deficiencies (TDDs) may be due to the use of different classification criteria. We present the combined analysis of two case-control studies, the U.S. Multistate CVS (US) study and the Italian Multicentric Birth Defects (IP-IMC) study, using two different definitions of TDDs. We compared the frequency of CVS exposure in control infants with that among those infants with any number of affected digits (any TDD), and those with all five digits of at least one limb affected (extensive TDDs). The estimated relative risk (RR) for any TDD following CVS was 10.6 (IPIMC) and 6.6 (US). For the extensive TDDs, the RR was 30.5 (IPIMC) and 10.7 (US). In both studies, extensive TDDs were less than 25% of all TDDs. Compared to all TDDs, extensive TDDs were more likely to occur after CVS performed earlier in the first trimester (before 10-11 weeks' gestation). These findings suggest a relationship between the timing of CVS and the severity of TDDs; indicate that using a restrictive definition of TDDs (all five digits affected) may limit the ability to evaluate the association between CVS and TDDs in populations in whom CVS is usually performed at or after 10 weeks' gestation; and highlight the necessity to consider gestational age in any evaluation of the relative risk for limb deficiencies associated with CVS.
View details for Web of Science ID A1996UA04200012
View details for PubMedID 8882399
Results of studies to determine whether women who smoke during early pregnancy are at increased risk of delivering infants with orofacial clefts have been mixed, and recently a gene-environment interaction between maternal smoking, transforming growth factor-alpha (TGFa), and clefting has been reported. Using a large population-based case-control study, we investigated whether parental periconceptional cigarette smoking was associated with an increased risk for having offspring with orofacial clefts. We also investigated the influence of genetic variation of the TGFa locus on the relation between smoking and clefting. Parental smoking information was obtained from telephone interviews with mothers of 731 (84.7% of eligible) orofacial cleft case infants and with mothers of 734 (78.2%) nonmalformed control infants. DNA was obtained from newborn screening blood spots and genotyped for the allelic variants of TGFa. We found that risks associated with maternal smoking were most elevated for isolated cleft lip with or without cleft palate, (odds ratio 2.1 [95% confidence interval 1.3-3.6]) and for isolated cleft palate (odds ratio 2.2 [1.1-4.5]) when mothers smoked > or =20 cigarettes/d. Analyses controlling for the potential influence of other variables did not reveal substantially different results. Clefting risks were even greater for infants with the TGFa allele previously associated with clefting whose mothers smoked > or =20 cigarettes/d. These risks for white infants ranged from 3-fold to 11-fold across phenotypic groups. Paternal smoking was not associated with clefting among the offspring of nonsmoking mothers, and passive smoke exposures were associated with at most slightly increased risks. This study offers evidence that the risk for orofacial clefting in infants may be influenced by maternal smoke exposures alone as well as in combination (gene-environment interaction) with the presence of the uncommon TGFa allele.
View details for Web of Science ID A1996TV56400014
View details for PubMedID 8644715
The role of periconceptional folic acid in the prevention of neural tube defects (NTDs) is well established. However, it is not clear whether a protective effect exists for the subset of nonsyndromic NTD with other "unrelated" major structural birth defects (NTD-multiples). This question is important to investigate because of shared pathogenetic mechanisms between NTD and other types of birth defects, and because of the epidemiologic differences that have been shown between NTD-multiples and NTD-singles. We analyzed data from two population-based case-control studies of NTDs, Atlanta 1968-1980, and California 1989-1991, to assess whether periconceptional multivitamin use reduces the risk of NTD-multiples. Maternal vitamin histories were assessed for 47 and 65 NTD-multiples cases and 3,029 and 539 control babies in Atlanta, and California, respectively. There was a substantial risk reduction associated with periconceptional multivitamin use (-3 to +3 months) for NTD-multiples (pooled odds ratio = 0.36, 95% C.I. 0.18-0.72) that persisted after adjustment for maternal race/ethnicity and education. Also, no specific types of NTDs or NTDs with specific defects explained the risk reduction with vitamin use. These data suggest that multivitamins reduce the risk of nonsyndromic NTD cases associated with other major birth defects. The implication of this finding for the role of vitamins in the prevention of non-NTD birth defects should be further explored.
View details for Web of Science ID A1996TM20600007
View details for PubMedID 8741914
We investigated whether a woman's periconceptional use of a multivitamin containing folic acid was associated with a reduced risk for delivering offspring with a conotruncal heart defect or a limb deficiency. Data were derived from a population-based case-control study of fetuses and liveborn infants with conotruncal or limb defects among a 1987-88 cohort of births in California. Telephone interviews were conducted with mothers of 207 (87.0% of eligible) conotruncal cases, 178 (82.0%) limb defect cases, and of 481 (76.2%) randomly selected liveborn nonmalformed control infants. Reduced risks were observed for maternal use of multivitamins containing folic acid from one month before until two months after conception. Odds ratios and 95% confidence intervals for any compared to no multivitamin use were 0.70 (0.46-1.1) for conotruncal defects and 0.64 (0.41-1.0) for limb defects. Controlling for maternal race/ethnicity, age, education, gravidity, alcohol use, and cigarette use resulted in a further reduction to the odds ratio for conotruncal defects, 0.53 (0.34-0.85), but not for limb defects. Among non-vitamin using women, consumption of cereal containing folic acid was also associated with reduced risk for both defects. Women who take multivitamins have 30-35% lower risk of delivering offspring with either conotruncal or limb defects. This association may not be attributable to folic acid specifically, but may be a consequence of other multivitamin components, or some unknown behaviors that highly correlate with regular use of a multivitamin. However, should the association prove causal, it offers an important opportunity for preventing thousands of serious birth defects.
View details for Web of Science ID A1995TG90800026
View details for PubMedID 8585581
Women are advised to take folic acid before they conceive as a precaution against neural-tube defects. However, the use of folic acid in preventing orofacial clefts is unknown. We investigated whether a woman's periconceptional use of multivitamins containing folic acid was associated with a reduced risk of orofacial clefts. We derived data from a population-based case-control study of fetuses and liveborn infants with orofacial anomalies among a 1987-89 cohort of births in California. We interviewed 731 (84.7%) of eligible mothers with orofacial cleft case infants and 734 (78.2%) mothers with non-malformed control infants. We found a reduced risk of orofacial clefts if the mother had used multivitamins containing folic acid during the period from one month before through two months after conception. The odds ratios ranged from 0.50-0.73 depending on cleft phenotype. Controlling for the potential influence of other variables did not substantially alter the results. Maternal daily consumption of cereal containing folic acid was also associated with a reduced risk of orofacial clefts. Women who used multivitamins containing folic acid periconceptionally had a 25-50% reduction in risk for offspring with orofacial clefts compared to women who did not use such vitamins. However, this association may not be attributable to folic acid specifically, but may be a consequence of other multivitamin supplement components, or behaviours, that are highly correlated with the use of multivitamins containing folic acid.
View details for Web of Science ID A1995RN65600007
View details for PubMedID 7623568
With a case-control study, we investigated whether periconceptional intake of supplemental or dietary folate reduced the risk of having a neural tube defect (NTD)-affected pregnancy. Mothers of 549 (88% of eligible) cases and 540 (88%) controls were interviewed in person about vitamin supplements used in either the 3 months before or the 3 months after conception and also about usual diet in the 3 months before conception. Women with any use of a folic acid-containing vitamin in the 3 months before conception had a lower risk of having an NTD-affected pregnancy [odds ratio (OR) = 0.65; 95% confidence interval (CI) = 0.45-0.94]. ORs were similar for 3 levels (< 0.4, 0.4-0.9, and > 0.9 mg per day) of average daily intake of folic acid. Any level of use in the first 3 months after conception resulted in a lowered risk as well (OR = 0.60; 95% CI = 0.46-0.79). Reduced risks were less marked for Hispanics and were not observed among women who graduated from college. Modest reduced risks were noted among non-vitamin users whose estimated daily dietary intake of folate was more than 0.227 mg. We observed decreasing risk with increasing folate intake from combined dietary sources and vitamin supplements. A reduction in NTD risk associated with folate intake is consistent with other studies; however, the reduced risk may be particular to subsets of the population, primarily non-Hispanic women and women whose education does not exceed high school.
View details for Web of Science ID A1995QU35400005
View details for PubMedID 7619926
This study examined the prevalence of congenital malformations across the maternal age spectrum and identified specific malformation types that contributed to the overall prevalence among mothers under the age of 20 years. Data were derived from the California Birth Defects Monitoring Program for 1983 through 1988 live births. The distribution of prevalences of all nonchromosomal malformations was U-shaped across maternal age. Furthermore, several specific malformation types, representing nearly every organ system, were elevated among the infants of women under 20 years of age in comparison with those of women 25 to 29 years old.
View details for Web of Science ID A1995QW83900020
View details for PubMedID 7733434
Although numerous infants have been reported with transverse limb deficiencies after their mothers had undergone chorionic villus sampling (CVS), it has been unclear whether the procedure caused these defects. We report the results of the first multistate case-control study to assess and quantify the risk for specific limb deficiencies associated with CVS. Case subjects were 131 infants with nonsyndromic limb deficiency ascertained from 7 population-based birth defect surveillance programs, and born from 1988-1992 to mothers 34 years of age or older. Control subjects were 131 infants with other birth defects. We ascertained exposure to CVS from medical records and maternal and physician questionnaires. We assessed rates and timing of exposure to CVS, and estimated relative and absolute risks for anatomic subtypes of limb deficiency. The odds ratio for all types of limb deficiency after CVS from 8-12 weeks' gestation was 1.7 (95% confidence interval, 0.4-6.3). For specific anatomic subtypes, the strongest association was for transverse digital deficiency (odds ratio = 6.4; 95% confidence interval, 1.1-38.6). The risk for transverse digital deficiency increased with earlier gestational exposure (P < 0.01 for trend). We estimated that the absolute risk for transverse digital deficiency in infants after CVS was 1 per 2,900 births (0.03%). Exposure to CVS was associated with a sixfold increase in risk for transverse digital deficiency. The causality of this association is supported by its strength, specificity, biologic plausibility, and consistency with the results of previous studies. Although some centers already inform patients about risk for limb deficiency, this study quantifies the magnitude of risk associated with CVS from 8-12 weeks' gestation.
View details for Web of Science ID A1995QQ24500003
View details for PubMedID 7597654
In epidemiologic studies of birth defects, occupational titles have frequently been used as surrogates for exposure. To avoid the error associated with such proxy exposure measures, we have designed a process in which an industrial hygienist systematically imputes exposures derived from maternal interviews. In response to a structured questionnaire, mothers of cases and controls recalled occupational and nonoccupational tasks performed or products used around the time of conception. Maternal exposures were then assigned to several a priori defined categories by an industrial hygienist. The central exposure category consists of 74 chemical families, e.g., alcohols, lead compounds. Other exposure categories are individual chemical compounds; nonchemical agents, e.g., ionizing radiation, infectious diseases; and product end-use categories, e.g., insecticides, combustion products. A detailed description of this approach and its exposure assessment potential is presented using exposure data from 220 maternal interviews.
View details for Web of Science ID A1994NQ32700001
View details for PubMedID 8074117
Concerns have been raised regarding a relation between residential and occupational electromagnetic (EM) field exposures and adverse reproductive effects. This paper reviews the epidemiologic evidence for this possible relation, including some pertinent methodologic issues, notes relevant findings from the experimental literature, and discusses areas for future research. Evidence is lacking for a strong association between a woman's use of a video display terminal (VDT) during pregnancy and spontaneous abortion. The evidence for a strong association between a women's use of a VDT and other adverse reproductive endpoints is also lacking, with some suggestive findings for congenital malformations and too few data to reach a conclusion about other endpoints. With respect to low-level EM field exposures other than VDTs, the paucity of data prevents one from determining whether there are reproductive health risks associated with such exposures. Therefore, this is an area that needs further investigation. Given that altered growth may be an underlying biologic effect of EM field exposures, endpoints that might be pursued in future studies include congenital malformations not associated with chromosomal anomalies, intrauterine growth retardation, and chromosomally normal spontaneous abortions.
View details for Web of Science ID A1993MY18000013
View details for PubMedID 8206019
This study addressed the question of how maternal migration between conception and birth affects estimates of risk in studies of congenital malformations when movement is related to the exposure. For example, in studying the potential association between proximity to a chemical waste site and the occurrence of birth defects, incorrect inferences might be drawn if maternal residence at birth was used as a surrogate for exposure at conception in the case when a significant amount of media attention influenced some women to move away from the site after becoming pregnant. A simple statistical model is proposed that defines the distance to a fixed exposure point measured at birth as a function of the distance to the point measured at conception, the probability of movement, the direction of movement, and the distance moved. Bias is the difference between the expected results when distance is measured at birth versus conception. The amount of bias can be substantial for movement patterns that may be likely to occur. This simplified model was used in an effort to explore and better understand the relationships between maternal migration and risk.
View details for Web of Science ID A1993LA30000009
View details for PubMedID 8476302
An important question in interpreting epidemiologic data is why some persons agree to participate in a health survey while others do not. Information about why people agree to interview or answer a questionnaire could help researchers to devise procedures for a health survey and to chose information to be communicated in the interview or questionnaire so as to increase subjects' participation. The authors interviewed 180 mothers who gave birth to a child with a birth defect and 198 mothers whose children were born without a birth defect. The interviews were part of two case-control studies to determine risk factors for selected birth defects. In the course of the interviews, each mother was asked why she agreed to be interviewed, and whether anything about the survey procedures that were followed could be improved. Among both the case mothers and the control mothers the most common reason for agreeing to be interviewed was humanitarian, expressed as "to help others" or "to prevent what happened to my baby from happening to babies in the future." Case mothers, more frequently than control mothers, gave as their reason for participating either to help themselves, their child, their family, or to further scientific understanding. Emphasizing these as benefits of participation to those who are survey subjects at the time of the initial contact could increase the proportion who agree to respond.
View details for Web of Science ID A1992KB79900021
View details for PubMedID 1454988
Biases familiar to all epidemiologists take on new importance when studying spontaneous abortion because of the significance of the timing of exposure during gestation, and because the gestational age at which the pregnancy is recognized may be related to risk factors under study. In this paper, we systematically review the principal biases that might affect epidemiologic studies of pregnancy loss, in the context of a series of studies that found associations between adverse reproductive outcomes and prenatal use of tap or bottled water. These biases relate to availability of subjects for study, exposure opportunity, recall of exposure, recall of disease, and confounding. In one of the studies, the rate of bottled water use changed dramatically over the course of the study period, providing an opportunity to test indirectly for biased recall of exposure. We conclude that a less complete recall of water intake among women with normal pregnancies, as compared with those with spontaneous abortions, may have produced, or increased the magnitude of, the associations seen in these studies.
View details for Web of Science ID A1992HH93800012
View details for PubMedID 1576219
Data on isolated oral cleft malformations from a birth defects registry covering a large population base were examined to describe potential associations with maternal and infant characteristics. Infants with cleft palate (CP) were analyzed separately from infants with cleft lip with or without cleft palate (CLP). The prevalence of isolated CLP per 1,000 births was 0.741, approximately twice the prevalence of isolated CP, which was 0.383. Male infants were more likely to be born with CLP (OR = 1.9) but less likely to be born with CP (OR = 0.56) than were females. Women 39 years or more of age were twice as likely as 25-29 year olds to have a child with either type of cleft. Black, nonhispanic infants had a lowered risk for CLP compared to white, nonhispanics (OR = 0.40). These risks were found to be independent of each other based on multivariate analyses. Associations with either type of cleft malformation were not observed for plurality, number of previous live births, and maternal birthplace.
View details for Web of Science ID A1991EZ23300005
View details for PubMedID 2014485
When detailed information on individuals is not available, databases of environmental measures are sometimes used in epidemiologic studies to provide data on human exposure. The use of such databases is based on the assumption that the data are representative of individual human exposure and are applicable to the study. Twenty-six databases that contained data on the environment pertaining to California were summarized and evaluated by categorical criteria of spatial and temporal precision, availability, amount of quantitative information, "machine-readability," and type of environmental measure.
View details for Web of Science ID A1990EN63700008
View details for PubMedID 2256714
This study used data obtained through interview with the mother to determine whether parental occupations from the California birth certificate were representative of maternal occupations during the first trimester of pregnancy or paternal occupations 3 months before conception. For 71% of mothers and 80% of fathers, the occupation on the birth certificate was the same as the occupation elicited from the interview. The sensitivity of the birth certificate for determining whether a mother or father was employed or employed in a particular standard occupational category ranged from 50 to 100%. The bias to the odds ratio associated with a sensitivity of 75% and a specificity of 80% is presented. The results suggest that the use of birth certificate information on parental occupation to screen for associations with congenital malformations will miss all but very strong associations.
View details for Web of Science ID A1990DG76200015
View details for PubMedID 2188499
Many studies have evaluated the likelihood of adverse health effects associated with environmental contamination from point source exposures. Two statistical measures used in these studies are the ratio, R, of the observed to the expected number of cases occurring in the area containing the point and the average distance, D, between the cases and the point. This paper estimates the probability of detecting an association between disease and exposure when one actually exists (power) for R and D for several specific and plausible statistical models. Results are presented in the context of rare diseases such as congenital malformations. The practical implications of using these measures for the evaluation of risk of disease in environmental epidemiologic investigations are discussed.
View details for Web of Science ID A1990DW53200006
View details for PubMedID 2386422
In November 1981, a leak of solvents from an underground storage tank was detected at an electronics manufacturing plant in Santa Clara County, California. Solvents (predominantly 1,1,1-trichloroethene, or methyl chloroform) were found in a nearby well which supplied drinking water to the surrounding community. Residents were concerned about a possible relation between adverse reproductive outcomes and consumption of contaminated water. To address this concern, the California Department of Health Services conducted two epidemiologic studies: one of these, reported here, is a county-wide study of cardiac anomalies. This study, which looked at major cardiac anomalies among births throughout Santa Clara County in 1981-1983, found an increased prevalence in the service area of the water company which operated the contaminated well. During the potentially exposed time period (January 1981 through August 1982), 12 babies with major cardiac anomalies were born to residents of this area. This represents an excess of six cases over the number expected based on the prevalence in the remainder of the county (relative risk = 2.2, 95 per cent confidence interval 1.2-4.0). No excess was observed in the unexposed time period (September 1982 through December 1983). However, the temporal distribution of major cardiac cases born during the exposed time period suggests that the solvent leak is an unlikely explanation for this excess.
View details for Web of Science ID A1989U333700003
View details for PubMedID 2784935
Highway patrol officers are the primary responders to hazardous material spills in California, yet little is known regarding the health effects resulting from this exposure. A historical cohort study of 993 California highway patrol officers who responded to hazardous material spills in 1984 was conducted. The records of officers who were exposed to acutely toxic chemicals were followed for the subsequent week to determine if they demonstrated more absenteeism or illness compared to officers who were not exposed to toxic chemicals. No significant differences in the frequency of absenteeism or illness was found between the two groups during the week following exposure. No indication was found that exposure to hazardous materials during a highway patrol spill response results in increased absenteeism.
View details for Web of Science ID A1989U001200008
View details for PubMedID 2930246
Patterns of disease in space are often analysed to determine whether a relationship exists between a disease outcome and environmental exposures. This report examines the performance of three cluster analytical methods when applied to a single data set. These methods, designed to assess the purely spatial variation of events, have been examined to assess their ability to detect clustering in an area where disease rates have previously been shown to be significantly elevated. The ability of these methods to detect spatial clustering was also examined using simulation techniques. All three methods were found to be poor at detecting spatially localized disease rates which were approximately three time the expected rate, as measured by the relative risk.
View details for Web of Science ID A1988T103100038
View details for PubMedID 3225103
The proportion of children born with a particular defect is not a "birth defect rate" but, rather, a prevalence proportion. The implications of confusing a rate and a proportion are discussed in terms of the interpretation of birth defect data. It is recommended that "prevalence proportion" or "prevalence" be used to report the frequency of various defects rather than the often-used "prevalence rate."
View details for Web of Science ID A1988Q752300004
View details for PubMedID 3238600
Maps transformed so as to have constant density of residential population were used to analyze the spatial distribution of disease in three specific areas. Each area had received recent attention because of suspected environmental pollution. The area adjacent to the Rocky Flats Facility (CO) was examined to identify any association between possible plutonium releases and increases in lung cancer or leukemia incidence. The industrial area of northern Contra Costa County (CA) was studied to explore a relationship between petrochemical industrial emissions and histologic-specific lung cancers. Finally, a suspected increase in the risk of congenital cardiac defects possibly related to pollution of the Santa Clara County (CA) water supply was investigated. No evidence of elevated risk of disease was found to be associated with either the Rocky Flats Facility or the polluted water of Santa Clara County. An increase in lung cancer, found by other investigators in earlier years, was shown to persist in association with industrial emissions in Contra Costa County.
View details for Web of Science ID A1987K015900003
View details for PubMedID 3476785
Data on hazardous material releases that occurred between January 1, 1982 and September 30, 1983 in California were obtained from the California Highway Patrol (CHP) and the US Department of Transportation (DOT). The majority of incidents involved highway transport of hazardous materials, although some information was available on air, rail, and stationary facility releases. Vehicle accidents and failure of or damage to the container were the most frequent causes of releases. Proportionately more hazardous materials incidents occurred in early summer than at other times of the year, during weekdays, and daytime hours. The largest proportions of incidents involved the chemical categories of corrosives and fuels. Reported exposures and injuries to response personnel and other people at the scene were relatively few; no fatalities were reported. Few incidents were reported in both data sources, suggesting that the examination of only one data source would yield a gross underestimate of the total number of hazardous materials incidents in California. The lack of available denominator data limits the interpretation of the findings.
View details for Web of Science ID A1986C009600012
View details for PubMedID 3963282