Maternal residential atrazine exposure and gastroschisis by maternal age

County-Level Atrazine Use and Gastroschisis

Importance

The incidence of gastroschisis, a birth defect involving the herniation of the small bowel through the abdominal wall, has increased in the US since the 1960s. The pesticide atrazine is a hypothesized cause of gastroschisis; however, examination of the association between atrazine and gastroschisis has been limited.

Objective

To evaluate national trends in gastroschisis incidence, maternal and infant characteristics associated with gastroschisis, and whether county-level atrazine use is associated with gastroschisis.

Design, Setting, and Participants

This retrospective, repeated cross-sectional study examined birth certificate data of all live births in the US and data on atrazine use from the US Geological Survey from January 1, 2009, through December 31, 2019. The data analysis was performed between August 5, 2021, and May 26, 2023.

Exposures

County-level atrazine use.

Main Outcomes and Measures

The primary outcome was gastroschisis incidence. Covariates included maternal age, race and ethnicity, body mass index (measured by weight in kilograms divided by height in meters squared), parity, insurance type, Chlamydia infection during pregnancy, smoking, and rurality. Mixed-effects logistic regression models (year fixed effects and county random effects) were constructed using different county-level atrazine exposure variables (1-, 5-, and 10-year means).

Results

Between 2009 and 2019, 39 282 566 live births were identified, with 10 527 infant diagnoses of gastroschisis. Infants with gastroschisis were more likely to have mothers who identified as non-Hispanic White (61% vs 54%; P < .001), had a lower body mass index (median [IQR], 23.4 [20.8-27.2] vs 25.4 [22.0-30.8]; P < .001), were more likely to be nulliparous (median [IQR], 0 [0-1] vs 1 [0-2]; P < .001), and were more commonly covered by Medicaid (63% vs 43%; P < .001). During the study period, the rate (per 1000 live births) of gastroschisis decreased from 0.31 (95% CI, 0.29-0.33) to 0.22 (95% CI, 0.21-0.24). The median (IQR) county-level atrazine use estimates were higher among infants with gastroschisis (1 year, 1389 [IQR, 198-10 162] vs 1023 [IQR, 167-6960] kg; 5 years, 1425 [IQR, 273-9895] vs 1057 [IQR, 199-6926] kg; 10 years, 1508 [IQR, 286-10 271] vs 1113 [IQR, 200-6650] kg; P < .001). In adjusted models, higher county levels of atrazine (each 100 000-kg increase) were associated with a higher incidence of gastroschisis (1 year: adjusted odds ratio [AOR], 1.12 [95% CI, 1.01-1.24]; 5 years: AOR, 1.15 [95% CI, 1.02-1.30]; 10 years: AOR, 1.21 [95% CI, 1.07-1.38]).

Conclusions and Relevance

In this cross-sectional study, higher county levels of atrazine were associated with infant diagnoses of gastroschisis. While atrazine is the second-most used herbicide in the US, numerous countries around the world have banned it out of concern for adverse effects on human health. These findings suggest that exploring alternatives to atrazine in the US may be warranted.

Developmental regulation of cellular metabolism is required for intestinal elongation and rotation

Malrotation of the intestine is a prevalent birth anomaly, the etiology of which remains poorly understood. Here, we show that late-stage exposure of Xenopus embryos to atrazine, a widely used herbicide that targets electron transport chain (ETC) reactions, elicits intestinal malrotation at high frequency. Interestingly, atrazine specifically inhibits the cellular morphogenetic events required for gut tube elongation, including cell rearrangement, differentiation and proliferation; insufficient gut lengthening consequently reorients the direction of intestine rotation. Transcriptome analyses of atrazine-exposed intestines reveal misexpression of genes associated with glycolysis and oxidative stress, and metabolomics shows that atrazine depletes key glycolytic and tricarboxylic acid cycle metabolites. Moreover, cellular bioenergetics assays indicate that atrazine blocks a crucial developmental transition from glycolytic ATP production toward oxidative phosphorylation. Atrazine-induced defects are phenocopied by rotenone, a known ETC Complex I inhibitor, accompanied by elevated reactive oxygen species, and rescued by antioxidant supplementation, suggesting that malrotation may be at least partly attributable to redox imbalance. These studies reveal roles for metabolism in gut morphogenesis and implicate defective gut tube elongation and/or metabolic perturbations in the etiology of intestinal malrotation.

Is gastroschisis associated with county-level socio-environmental quality during pregnancy?

BACKGROUND

Gastroschisis prevalence more than doubled between 1995 and 2012. While there are individual-level risk factors (e.g., young maternal age, low body mass index), the impact of environmental exposures is not well understood.

METHODS

We used the U.S. Environmental Protection Agency's Environmental Quality Index (EQI) as a county-level estimate of cumulative environmental exposures for five domains (air, water, land, sociodemographic, and built) and overall from 2006 to 2010. Adjusted odds ratios (aOR) and 95% confidence interval (CI) were estimated from logistic regression models between EQI tertiles (better environmental quality (reference); mid; poorer) and gastroschisis in the National Birth Defects Prevention Study from births delivered between 2006 and 2011. Our analysis included 594 cases with gastroschisis and 4105 infants without a birth defect (controls).

RESULTS

Overall EQI was modestly associated with gastroschisis (aOR [95% CI]: 1.29 [0.98, 1.71]) for maternal residence in counties with poorer environmental quality, compared to the reference (better environmental quality). Within domain-specific indices, only the sociodemographic domain (aOR: 1.51 [0.99, 2.29]) was modestly associated with gastroschisis, when comparing poorer to better environmental quality.

CONCLUSIONS

Future work could elucidate pathway(s) by which components of the sociodemographic domain or possibly related psychosocial factors like chronic stress potentially contribute to risk of gastroschisis.

Factors Associated with Hospital Readmission One Year Post-Discharge in Infants with Gastroschisis

INTRODUCTION

Gastroschisis is the most common congenital abdominal wall defect with a rising prevalence. Infants with gastroschisis are at risk for multiple complications, leading to a potential increased risk for hospital readmission after discharge. We aimed to find the frequency and factors associated with an increased risk of readmission.

METHODS

A retrospective analysis of infants born with gastroschisis between 2013 and 2019 who received initial surgical intervention and follow-up care in the Children's Wisconsin health system was performed. The primary outcome was the frequency of hospital readmission within 1 year of discharge. We also compared maternal and infant clinical and demographic variables between those readmitted for reasons related to gastroschisis, and those readmitted for other reasons or not readmitted.

RESULTS

Forty of 90 (44%) infants born with gastroschisis were readmitted within 1-year of the initial discharge date, with 33 (37%) of the 90 infants being readmitted due to reasons directly related to gastroschisis. The presence of a feeding tube (p < 0.0001), a central line at discharge (p = 0.007), complex gastroschisis (p = 0.045), conjugated hyperbilirubinemia (p = 0.035), and the number of operations during the initial hospitalization (p = 0.044) were associated with readmission. Maternal race/ethnicity was the only maternal variable associated with readmission, with Black race being less likely to be readmitted (p = 0.003). Those who were readmitted were also more likely to be seen in outpatient clinics and utilize emergency healthcare resources. There was no statistically significant difference in readmission based on socioeconomic factors (all p > 0.084).

CONCLUSION

Infants with gastroschisis have a high hospital readmission rate, which is associated with a variety of risk factors including complex gastroschisis, multiple operations, and the presence of a feeding tube or central line at discharge. Improved awareness of these risk factors may help stratify patients in need of increased parental counseling and additional follow-up.

Impact of High-Throughput Model Parameterization and Data Uncertainty on Thyroid-Based Toxicological Estimates for Pesticide Chemicals

Chemical-induced alteration of maternal thyroid hormone levels may increase the risk of adverse neurodevelopmental outcomes in offspring. US federal risk assessments rely almost exclusively on apical endpoints in animal models for deriving points of departure (PODs). New approach methodologies (NAMs) such as high-throughput screening (HTS) and mechanistically informative in vitro human cell-based systems, combined with in vitro to in vivo extrapolation (IVIVE), supplement in vivo studies and provide an alternative approach to calculate/determine PODs. We examine how parameterization of IVIVE models impacts the comparison between IVIVE-derived equivalent administered doses (EADs) from thyroid-relevant in vitro assays and the POD values that serve as the basis for risk assessments. Pesticide chemicals with thyroid-based in vitro bioactivity data from the US Tox21 HTS program were included (n = 45). Depending on the model structure used for IVIVE analysis, up to 35 chemicals produced EAD values lower than the POD. A total of 10 chemicals produced EAD values higher than the POD regardless of the model structure. The relationship between IVIVE-derived EAD values and the in vivo-derived POD values is highly dependent on model parameterization. Here, we derive a range of potentially thyroid-relevant doses that incorporate uncertainty in modeling choices and in vitro assay data.

Exposure to Atrazine through gestation and lactation period led to impaired sexual maturation and subfertility in F1 male rats with congenital deformities in F2 progeny

Several scientific reports suggest perturbed reproductive and developmental defects associated with environmental exposure to Atrazine (ATR). ATR has been associated with altered endocrine and reproductive functioning in-vivo exposed during the critical window of development. Thus, the present study investigates the effect of ATR exposure on F1-F2 male progeny exposed through gestation and lactation. F0 dams administered with ATR at doses 2, 10, 70, and 100 mg/kg b. wt/day from gestation day 6 to postnatal day 21. The F1 male rats were monitored for sexual maturation and subjected to fertility assessment on PND75. Delayed testicular descent was observed in 10, 70, and 100 mg/kg b. wt/day ATR dose with significantly lower serum testosterone, sperm count, and motility with testicular defects in F1 male. Expression of Androgen receptor (AR), Estrogen receptors (ER α and ER β), StAR, Aromatase, and INSL-3 were upregulated at all doses indicating estrogenic/anti-androgenic activity of ATR. Fertility assessment revealed subfertility in F1 males with high (%) pre- and post-implantation loss at 10, 70, and 100 mg/kg b. wt/day dose as compared to control. Further, F2 fetuses exhibited congenital disabilities viz. decreased weight, crown-rump length, and anogenital distance with several other morphological deformities. To conclude, ATR exerted estrogenic and/or anti-androgenic activity with fetotoxic effects through the male germline.

Trends in prevalence and spatiotemporal distribution of gastroschisis in Arkansas, 1998-2015

BACKGROUND

Arkansas (AR) had the highest prevalence of gastroschisis in a recent study including 15 U.S. states. Our objective was to evaluate trends in prevalence and the spatiotemporal distribution of gastroschisis in AR.

METHODS

Infants with gastroschisis, born 1998-2015, were identified from the Arkansas Reproductive Health Monitoring System. Birth record data were used as denominators for calculations. Maternal residence at delivery was geocoded for spatial analyses. Annual prevalence rates (PRs) were calculated. Joinpoint regression analysis was performed to examine trends in gastroschisis and report the annual percent changes (APCs) in PRs. Spatiotemporal analyses identified counties with unusually high PRs of gastroschisis. Poisson regression, including county, year, and county*year indicators, was fit to evaluate the PRs of gastroschisis, while adjusting for county-level maternal variables.

RESULTS

We identified 401 cases of gastroschisis among 694,459 live births. The overall PR of gastroschisis was 5.8/10,000 live births. The prevalence of gastroschisis had a significant APC of +5.3% (p < .0001) between 1998 and 2012, followed by a nonsignificant yearly average decrease of -17% through 2015 (p = 0.2). The Emerging Hot Spot Analysis and SaTScan identified an overlapping five-county cluster from 2006 to 2013. Poisson regression model, including county (inside vs. outside cluster), time (before vs. after 2006), and county*time indicators, was fit to evaluate the PRs of gastroschisis. The model did not confirm the presence of a spatiotemporal cluster, once it adjusted for county-level maternal characteristics (p = .549).

CONCLUSION

Close monitoring of rates of gastroschisis is warranted to determine if the PRs of gastroschisis continue to decline in AR.

Determining maternal risk factors for gastroschisis using colorado's birth registry database

AIM OF STUDY

Gastroschisis is a congenital abdominal wall defect which results in herniation of abdominal contents. The objective of this study was to determine the maternal risk factors for gastroschisis in Colorado.

METHODS

A case-control study was performed using the Birth Registry database from 2007 to 2016. The outcome was gastroschisis, and the main variable was maternal age which was divided into <21, 21-30, and >30 years of age. Descriptive analysis, bivariate analysis, and logistic regression was performed.

RESULTS

There were 236 cases of gastroschisis compared to 944 controls. Maternal age did vary significantly between groups (23.4 ± 5 years (cases) vs. 28.7 ± 5.9 years (controls); p < 0.0001). Unadjusted analysis demonstrated that those with young maternal age (<21 years of age) had a 14.14 (95% CI 8.44-23.67) higher odds of gastroschisis compared to those >30 years of age. Independent risk factors for gastroschisis were exposure to prenatal and first trimester cigarettes, prenatal and first trimester alcohol, and chlamydia infection. The odds (4.41, 95% CI 1.36-14.26) of gastroschisis were highest in those with first trimester cigarette exposure and young maternal age (p = 0.03).

CONCLUSIONS

Young maternal age, cigarette exposure, alcohol exposure, and chlamydia infection increase the odds of gastroschisis. The interaction between young maternal age and first trimester cigarette exposure significantly increases the odds of gastroschisis.

TYPE OF STUDY

Prognosis Study.

LEVEL OF EVIDENCE

Level III.

Increasing prevalence, time trend and seasonality of gastroschisis in São Paulo state, Brazil, 2005-2016

To estimate the gastroschisis seasonality and trend of prevalence in recent years, stratified by maternal age and geographical clusters of São Paulo state, a population-based study was designed. We used data from the Live Births Information System (SINASC) in São Paulo state, Brazil, from 2005 to 2016. Trends of prevalence were evaluated for the specific subgroups using the Prais-Winsten regression model, and the Durbin-Watson test was used, to estimate the regression coefficient, the annual percent change (APC), and 95% confidence interval (CI). We observed 1576 cases of gastroschisis among 7,317,657 live births (LB), a prevalence of 2.154 (95% CI: 2.047-2.260) per 10,000 LB which included, 50.6% males, 67.4% Caucasians, 53.4% preterm births, and 80.9% caesarean births. The prevalence of gastroschisis significantly increased by 2.6% (95% CI: 0.0-5.2) per year, and this trend was higher in mothers aged 30-34 years (APC: 10.2, 95% CI: 1.4-19.4) than in mothers of other age groups. Between 2011 and 2016, we identified the existence of seasonality based on the date of conception in the middle months of the year (p = 0.002). This is the first and largest population-based study summarizing current epidemiology and identifying trend of prevalence of gastroschisis in São Paulo state.

QSAR analysis of immune recognition for triazine herbicides based on immunoassay data for polyclonal and monoclonal antibodies

A common task in the immunodetection of structurally close compounds is to analyze the selectivity of immune recognition; it is required to understand the regularities of immune recognition and to elucidate the basic structural elements which provide it. Triazines are compounds of particular interest for such research due to their high variability and the necessity of their monitoring to provide safety for agricultural products and foodstuffs. We evaluated the binding of 20 triazines with polyclonal (pAb) and monoclonal (mAb) antibodies obtained using atrazine as the immunogenic hapten. A total of over 3000 descriptors were used in the quantitative structure-activity relationship (QSAR) analysis of binding activities (pIC₅₀). A comparison of the two enzyme immunoassay systems showed that the system with pAb is much easier to describe using 2D QSAR methodology, while the system with mAb can be described using the 3D QSAR CoMFA. Thus, for the 3D QSAR model of the polyclonal antibodies, the main statistical parameter q² (‘leave-many-out’) is equal to 0.498, and for monoclonal antibodies, q² is equal to 0.566. Obviously, in the case of pAb, we deal with several targets, while in the case of mAb the target is one, and therefore it is easier to describe it using specific fields of molecular interactions distributed in space.

Maternal residential exposure to specific agricultural pesticide active ingredients and birth defects in a 2003-2005 North Carolina birth cohort

BACKGROUND

Previously we observed elevated odds ratios (ORs) for total pesticide exposure and 10 birth defects: three congenital heart defects and structural defects affecting the gastrointestinal, genitourinary and musculoskeletal systems. This analysis examines association of those defects with exposure to seven commonly applied pesticide active ingredients.

METHODS

Cases were live-born singleton infants from the North Carolina Birth Defects Monitoring Program linked to birth records for 2003-2005; noncases served as controls (total n = 304,906). Pesticide active ingredient exposure was assigned using a previously constructed metric based on crops within 500 m of residence, dates of pregnancy, and likely chemical application dates for each pesticide-crop combination. ORs (95% CI) were estimated with logistic regression for categories of exposure compared to unexposed. Models were adjusted for maternal race/ethnicity, age at delivery, education, marital status, and smoking status.

RESULTS

Associations varied by birth defect and pesticide combinations. For example, hypospadias was positively associated with exposures to 2,4-D (OR_{50th to <90th percentile} : 1.39 [1.18, 1.64]), mepiquat (OR_{50th to <90th percentile} : 1.10 [0.90, 1.34]), paraquat (OR_{50th to <90th} : 1.14 [0.93, 1.39]), and pendimethalin (OR_{50th to <90th} : 1.21 [1.01, 1.44]), but not S-metolachlor (OR_{50th to <90th} : 1.00 [0.81, 1.22]). Whereas atrial septal defects were positively associated with higher levels of exposure to glyphosate, cyhalothrin, S-metolachlor, mepiquat, and pendimethalin (ORs ranged from 1.22 to 1.35 for 50th to <90th exposures, and 1.72 to 2.09 for >90th exposures); associations with paraquat were null or inconsistent (OR 50th to <90th: 1.05 (0.87, 1.27).

CONCLUSION

Our results suggest differing patterns of association for birth defects with residential exposure to seven pesticide active ingredients in North Carolina.

Epidemiology of gastroschisis: A population-based study in California from 1995 to 2012

BACKGROUND

Although the incidence of gastroschisis is increasing, risk factors are not clearly identified.

METHODS

Using the Linked Birth Database from the California Office of Statewide Health Planning and Development from 1995 to 2012, patients with gastroschisis were identified by ICD-9 diagnosis/procedure code or birth certificate designation. Logistic regressions examined demographics, birth factors, and maternal exposures on risk of gastroschisis.

RESULTS

The prevalence of gastroschisis was 2.7 cases per 10,000 live births. Patients with gastroschisis had no difference in fetal exposure to alcohol (p = 0.609), narcotics (p = 0.072), hallucinogenics (p = 0.239), or cocaine (p = 0.777), but had higher exposure to unspecified/other noxious substances (OR 3.27, p = 0.040; OR 2.02, p = 0.002). Gastroschisis was associated with low/very low birthweight (OR 5.08-16.21, p < 0.001) and preterm birth (OR 3.26-10.0, p < 0.001). Multivariable analysis showed lower risk in black (OR 0.44, p < 0.001), Asian/Pacific Islander (OR 0.76, p = 0.003), and Hispanic patients (OR 0.72, p < 0.001) compared to white patients. Risk was higher in rural areas (OR 1.24-1.76, p = 0.001). Compared to women age < 20, risk decreased with advancing maternal age (OR 0.49-OR 0.03, p < 0.001). Patients with gastroschisis had increased total charges ($336,270 vs. $9012, p < 0.001) and length of stay (38.1 vs. 2.9 days, p < 0.001). Mortality was 4.6%.

CONCLUSIONS

This is the largest population-based study summarizing current epidemiology of gastroschisis in California.

TYPE OF STUDY

Retrospective comparative cohort study.

LEVEL OF EVIDENCE

III.

Association of pesticide exposure with human congenital abnormalities

Human pesticide exposure can occur both occupationally and environmentally during manufacture and after the application of indoor and outdoor pesticides, as well as through consumption via residues in food and water. There is evidence from experimental studies that numerous pesticides, either in isolation or in combination, act as endocrine disruptors, neurodevelopmental toxicants, immunotoxicants, and carcinogens. We reviewed the international literature on this subject for the years between 1990 and 2017. The studies were considered in this review through MEDLINE and WHO resources. Out of the n = 1817 studies identified, n = 94 were reviewed because they fulfilled criteria of validity and addressed associations of interest. Epidemiological studies have provided limited evidence linking pre- and post-natal exposure to pesticides with cancers in childhood, neurological deficits, fetal death, intrauterine growth restriction, preterm birth, and congenital abnormalities (CAs). In this review, the potential association between pesticide exposure and the appearance of some human CAs (including among others musculoskeletal abnormalities; neural tube defects; urogenital and cardiovascular abnormalities) was investigated. A trend towards a positive association between environmental or occupational exposure to some pesticides and some CAs was detected, but this association remains to be substantiated. Main limitations of the review include inadequate exposure assessment and limited sample size. Adequately powered studies with precise exposure assessments such as biomonitoring, are warranted to clarify with certainty the potential association between pesticide exposure and human CAs.

Using Watershed Boundaries to Map Adverse Health Outcomes: Examples From Nebraska, USA

In 2009, a paper was published suggesting that watersheds provide a geospatial platform for establishing linkages between aquatic contaminants, the health of the environment, and human health. This article is a follow-up to that original article. From an environmental perspective, watersheds segregate landscapes into geospatial units that may be relevant to human health outcomes. From an epidemiologic perspective, the watershed concept places anthropogenic health data into a geospatial framework that has environmental relevance. Research discussed in this article includes information gathered from the literature, as well as recent data collected and analyzed by this research group. It is our contention that the use of watersheds to stratify geospatial information may be both environmentally and epidemiologically valuable.

Gastroschisis. Case report and management in primary care services

Introducción. La gastrosquisis es una enfermedad de baja prevalencia, pero de muy buen pronóstico si se realiza un adecuado manejo inicial. El presente escrito tiene como objetivo realizar una descripción de esta patología, destacando la importancia de su correcto manejo en el primer nivel.Presentación del caso. Neonato a término con hallazgo de gastrosquisis en primer nivel quien fue remitido al servicio de neonatología de una institución de tercer nivel. El infante recibió manejo interdisciplinario y cierre quirúrgico gradual y tuvo evolución favorable tras 3 meses de hospitalización.Discusión. No existe claridad sobre la causa exacta de la gastrosquisis, ya que es una enfermedad multifactorial. Su diagnóstico puede realizarse desde la etapa prenatal mediante la ultrasonografía, un método que posee alta sensibilidad y especificidad para su detección.Conclusión. La gastrosquisis es una enfermedad que para su diagnóstico y tratamiento requiere de personal especializado en primer nivel, lo que garantiza un correcto manejo inicial y evita futuras complicaciones.

Possible etiologies of increased incidence of gastroschisis

PURPOSE

Gastroschisis incidence has increased over the past decade nationally and in Hawaii. Pesticides have been implicated as potential causative factors for gastroschisis, and use of restricted use pesticides (RUPs) is widespread in Hawaii. This study was conducted to characterize gastroschisis cases in Hawaii and determine whether RUP application correlates with gastroschisis incidence.

METHODS

Gastroschisis patients treated in Hawaii between September, 2008 and August, 2015 were mapped by zip code along with RUP use. Spatial analysis software was used to identify patients' homes located within the pesticide application zone and agricultural land use areas.

RESULTS

71 gastroschisis cases were identified. 2.8% of patients were from Kauai, 64.8% from Oahu, 16.9% from Hawaii, 14.1% from Maui, and 1.4% from Molokai. RUPs have been used on all of these islands. 78.9% of patients lived in zip codes overlapping agricultural land use areas. 85.9% of patients shared zip codes with RUP-use areas.

CONCLUSION

The majority of gastroschisis patients were from RUP-use areas, supporting the idea that pesticides may contribute to the development of gastroschisis, although limited data on specific releases make it difficult to apply these findings. As more RUP-use data become available to the public, these important research questions can be investigated further.

Maternal Antibodies to Herpes Virus Antigens and Risk of Gastroschisis in Offspring

Gastroschisis risk is highest in offspring of young women and is increasing in prevalence, suggesting that exposures that are increasingly common among younger females may be causal. Some infections by viruses in the herpes family are more common in the earlier childbearing years and have been increasing in prevalence over time. Data from the Finnish Maternity Cohort were linked to Finnish malformation and birth registers (1987-2012) for this study, a nested case-control study of mothers of offspring with gastroschisis and age-matched controls. Maternal antibody responses in early pregnancy (mean gestational age = 11.1 weeks) to Epstein Barr virus (EBV), herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), and cytomegalovirus were measured. Conditional logistic regression models were used to estimate odds ratios (and 95% confidence intervals) for high immunoglobulin reactivity. Odds ratios for high immunoglobulin M (IgM) reactivity to EBV-viral capsid antigen and HSV-1 or HSV-2 (as indicators of recent infection) were 2.16 (95% confidence interval (CI): 0.97, 4.79) and 1.94 (95% CI: 0.74, 5.12), respectively. For higher immunoglobulin G (IgG) reactivity to EBV-viral capsid antigen and HSV-2 IgG, odds ratios were 2.16 (95% CI: 0.82, 5.70) and 2.48 (95% CI: 1.50, 4.10), respectively. Reactivities to HSV-1 IgG, cytomegalovirus IgM, or cytomegalovirus IgG did not appear to increase gastroschisis risk. Primary EBV infection was not associated with gastroschisis, but observed associations with both IgM and IgG reactivities to EBV and HSV suggest that reactivations may be risk factors for it.

Maternal and community predictors of gastroschisis and congenital diaphragmatic hernia in Canada

PURPOSE

The incidence of gastroschisis (GS) has increased globally. Maternal age and smoking are risk factors and aboriginal communities may be more commonly affected. Factors leading to this increased incidence are otherwise unclear. We investigate maternal sociodemography, air pollution and personal risk factors comparing mothers of infants with GS with a control group of infants with diaphragmatic hernia (CDH) in a large population-based analysis.

METHODS

Data were collected from a national, disease-specific pediatric surgical database (May 2006-June 2013). Maternal community sociodemographic information was derived from the Canadian 2006 Census. Univariate and multivariable analyses were performed examining maternal factors related to diagnosis of GS.

RESULTS

GS infants come from poorer, less educated communities with more unemployment, less pollution, fewer immigrants, and more aboriginal peoples than infants with CDH. Teen maternal age, smoking, and illicit drug use, are associated with GS.

CONCLUSION

Mothers of infants with GS are younger, more likely to smoke and come from socially disadvantaged communities with higher proportions of aboriginal peoples but lower levels of air pollution compared to mothers of CDH infants. Identification of maternal risks provides direction for prenatal screening and public health interventions.

Spatial analysis of gastroschisis in the National Birth Defects Prevention Study

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Air toxics and birth defects: a Bayesian hierarchical approach to evaluate multiple pollutants and spina bifida

BACKGROUND

While there is evidence that maternal exposure to benzene is associated with spina bifida in offspring, to our knowledge there have been no assessments to evaluate the role of multiple hazardous air pollutants (HAPs) simultaneously on the risk of this relatively common birth defect. In the current study, we evaluated the association between maternal exposure to HAPs identified by the United States Environmental Protection Agency (U.S. EPA) and spina bifida in offspring using hierarchical Bayesian modeling that includes Stochastic Search Variable Selection (SSVS).

METHODS

The Texas Birth Defects Registry provided data on spina bifida cases delivered between 1999 and 2004. The control group was a random sample of unaffected live births, frequency matched to cases on year of birth. Census tract-level estimates of annual HAP levels were obtained from the U.S. EPA's 1999 Assessment System for Population Exposure Nationwide. Using the distribution among controls, exposure was categorized as high exposure (>95(th) percentile), medium exposure (5(th)-95(th) percentile), and low exposure (<5(th) percentile, reference). We used hierarchical Bayesian logistic regression models with SSVS to evaluate the association between HAPs and spina bifida by computing an odds ratio (OR) for each HAP using the posterior mean, and a 95% credible interval (CI) using the 2.5(th) and 97.5(th) quantiles of the posterior samples. Based on previous assessments, any pollutant with a Bayes factor greater than 1 was selected for inclusion in a final model.

RESULTS

Twenty-five HAPs were selected in the final analysis to represent "bins" of highly correlated HAPs (ρ > 0.80). We identified two out of 25 HAPs with a Bayes factor greater than 1: quinoline (ORhigh = 2.06, 95% CI: 1.11-3.87, Bayes factor = 1.01) and trichloroethylene (ORmedium = 2.00, 95% CI: 1.14-3.61, Bayes factor = 3.79).

CONCLUSIONS

Overall there is evidence that quinoline and trichloroethylene may be significant contributors to the risk of spina bifida. Additionally, the use of Bayesian hierarchical models with SSVS is an alternative approach in the evaluation of multiple environmental pollutants on disease risk. This approach can be easily extended to environmental exposures, where novel approaches are needed in the context of multi-pollutant modeling.

Early pregnancy agricultural pesticide exposures and risk of gastroschisis among offspring in the San Joaquin Valley of California

BACKGROUND

Prevalence of gastroschisis has inexplicably been increasing over the past few decades. Our intent was to explore whether early gestational exposures to pesticides were associated with risk of gastroschisis.

METHODS

We used population-based data, accompanied by detailed information from maternal interviews as well as information on residential proximity to a large number of commercial pesticide applications during early pregnancy. The study population derived from the San Joaquin Valley of California (). Cases were 156 infants/fetuses with gastroschisis and controls were 785 infants without birth defects.

RESULTS

Among 22 chemical pesticide groups analyzed, none had an elevated odds ratio with an associated confidence interval that excluded 1.0, although exposure to the triazine group showed borderline significance. Among 36 specific pesticide chemicals analyzed, only exposure to petroleum distillates was associated with an elevated risk, odds ratio = 2.5 (1.1-5.6). In general, a substantially different inference was not derived when analyses were stratified by maternal age or when risk estimation included adjustment for race/ethnicity, body mass index, folic acid supplement use, and smoking.

CONCLUSION

Our study rigorously adds to the scant literature on this topic. Our a priori expectation was that we would observe certain pesticide compounds to be particularly associated with young age owing to the disproportionate risk observed for young women to have offspring with gastroschisis. We did not observe an exposure profile unique to young women.

Atrazine and pregnancy outcomes: a systematic review of epidemiologic evidence

Atrazine (ATR) is a commonly used agricultural herbicide that has been the subject of epidemiologic studies assessing its relation to reproductive health problems. This review evaluates both the consistency and the quality of epidemiologic evidence testing the hypothesis that ATR exposure, at usually encountered levels, is a risk factor for birth defects, small for gestational age birth weight, prematurity, miscarriages, and problems of fetal growth and development. We followed the current methodological guidelines for systematic reviews by using two independent researchers to identify, retrieve, and evaluate the relevant epidemiologic literature on the relation of ATR to various adverse outcomes of birth and pregnancy. Each eligible paper was summarized with respect to its methods and results with particular attention to study design and exposure assessment, which have been cited as the main areas of weakness in ATR research. As a quantitative meta-analysis was not feasible, the study results were categorized qualitatively as positive, null, or mixed. The literature on ATR and pregnancy-related health outcomes is growing rapidly, but the quality of the data is poor with most papers using aggregate rather than individual-level information. Without good quality data, the results are difficult to assess; however, it is worth noting that none of the outcome categories demonstrated consistent positive associations across studies. Considering the poor quality of the data and the lack of robust findings across studies, conclusions about a causal link between ATR and adverse pregnancy outcomes are not warranted.