Maternal occupational pesticide exposure and risk of congenital heart defects in the National Birth Defects Prevention Study

The use of high-resolution SNP arrays to detect congenital cardiac defects

OBJECTIVE

Copy number variations (CNVs) detected by high-resolution single nucleotide polymorphism microarrays (SNP arrays) have been associated with congenital heart defects (CHDs). The genetic mechanism underlying the development of CHDs remains unclear.

METHODS

High-resolution SNP arrays were used to detect CNVs and traditional chromosomal analyses, respectively, were carried out on 60 and 249 fetuses from gestational 12-37 weeks old, having isolated or complex CHDs that were diagnosed using prenatal ultrasound.

RESULTS

Twenty of the 60 fetuses (33.5%) had abnormalities, of which 23 CNVs (12 pathogenic, five probable pathogenic and six of undetermined significance) were detected by SNP arrays, and two distinct CNVs were present in three of these fetuses. In addition, in 39 patients with isolated congenital heart disease who had normal karyotypes, abnormal CNVs were present in 28.2% (11/39), and in patients with complex coronary artery disease, 19.0% (4/21) had abnormal karyotypes and 42.9% (9/21) had abnormal CNVs. In patients with complex coronary artery disease, 19.0% (4/21) had abnormal karyotypes and 42.9% (9/21) had abnormal CNVs.

CONCLUSIONS

In conclusion, genome-wide high-resolution SNP array can improve the diagnostic rate and uncover additional pathogenic CNVs. The submicroscopic deletions and duplications of Online Mendelian Inheritance in Man (OMIM) genes found in this study have haploinsufficient (deletion) or triplosensitive (duplication) traits, which further clarify the etiology and inheritance of CHDs.

Exposure to Endocrine-Disrupting Chemicals and Congenital Heart Diseases: The Pooled Results Based on the Current Evidence

The relationships between maternal exposure to endocrine-disrupting chemicals (EDCs) and congenital heart diseases (CHD) are not elucidated yet. The exposure levels of EDCs are generally estimated based on self-reported questionnaires or occupational exposure evaluations in the literature. Therefore, a study based on epidemiological data from human biospecimens is required to provide stronger evidence between maternal exposure to EDC and CHD. Embase, Pubmed, Scopus, and the Cochrane Library databases were searched for related research which provided risk estimates regarding the relationships between maternal EDC exposure and CHD in human offspring. Baseline characteristics and outcomes of CHD were extracted from each included study. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled to calculate the overall estimates of CHD. Subgroup and meta-regression analyses were performed to identify the sources of heterogeneity. Bootstrapping techniques were used in analyses where several studies originated from a similar population. A total of seventeen studies were involved in the meta-analyses. Maternal EDC exposure was significantly related to CHD in offspring (OR 2.15; 95%CI 1.64 to 2.83). EDC exposure was significantly associated with septal defects (OR 2.34; 95%CI 1.77 to 3.10), conotruncal defects (OR 2.54; 95%CI 1.89 to 3.43), right ventricular outflow tract obstruction (OR 2.65; 95%CI 1.73 to 4.07), left ventricular outflow tract obstruction (OR 3.58; 95%CI 2.67 to 4.79), anomalous pulmonary venous return (OR 2.31; 95%CI 1.34 to 4.00), and other heart defects (OR 2.49; 95%CI 1.75 to 3.54). In addition, maternal exposure to heavy metals, which included lead (OR 2.19; 95%CI 1.29 to 3.71), cadmium (OR 1.81; 95%CI 1.28 to 2.56), mercury (OR 2.23; 95%CI 1.13 to 4.44), and manganese (OR 2.65; 95%CI 1.48 to 4.74), increased risks for CHD significantly. In conclusion, based on the latest evidence, maternal EDC exposure may increase CHD risks in human offspring, especially in heavy metal exposure conditions.

Maternal Exposure to Extreme Cold Events and Risk of Congenital Heart Defects: A Large Multicenter Study in China

Over the past decade, extreme temperature events have become more frequent and longer in duration. Previous studies on the association between extreme cold events (ECEs) and congenital heart defects (CHDs) are few and inconsistent. We conducted a national multicenter study in 1313 hospitals in 26 provinces in China and collected a total of 14 808 high CHD-risk participants from 2013 to 2021. We evaluated the ECEs experienced by each pregnant women during the embryonic period (3-8 weeks). The results indicated that ECEs experienced by pregnant women during the embryonic period were associated with the development of fetal CHD and were more strongly associated with some specific fetal CHD subtypes, such as pulmonary stenosis, pulmonary atresia, and tetralogy of Fallot. Of the CHD burden, 2.21% (95% CI: 1.43, 2.99%)-2.40% (95% CI: 1.26, 3.55%) of fetal CHD cases were attributable to ECEs during the embryonic period. Our findings emphasize the need to pay more attention to pregnant women whose embryonic period falls during the cold season to reduce cold spell detriments to newborns.

Exposure to pesticides during pregnancy and the risk of neural tube defects: A systematic review

Exposure to pesticides during pregnancy has been associated with several serious congenital malformations, such as neural tube defects, therefore, is a cause for concern in terms of human health. This review aims to gather information related to maternal exposure during pregnancy and the risk of triggering neural tube defects in the offspring. The search strategy for the studies followed the PRISMA guidelines. We conducted a systematic search in the Science Direct, PubMed, Cochrane Library, Embase, Scopus, and Web of Science databases for all epidemiological studies that sought to associate exposure to pesticides during embryonic development with the risk of neural tube defects (NTDs). The keywords used were "pesticide", "herbicide", "congenital" and "neural". Of the 229 articles, 8 eligible ones (7 case-control and 1 cross-sectional) evaluated pesticide exposure in pregnancy. Different methods were used, including analysis of biological samples and questionnaires. The pesticides studied included insecticides, herbicides, fungicides, and nematicides. Insecticides were the most studied, with variations in concentrations between tissues and studies. Distinct levels of pesticides have been detected in maternal serum, placenta, and umbilical cord. Models were statistically adjusted for confounding factors, such as smoking and dietary supplement intakes. Concentrations were measured in different exposure windows (periconception and prenatal), related to NTDs such as anencephaly and spina bifida. Different data collection techniques, types of biological samples, and exposure windows were used, which made comparison difficult. The main pesticides studied included DDT, DDE, HCH, and endosulfan. Maternal serum showed the highest concentrations of pesticides, but detection in placental tissue and umbilical cord confirms embryonic exposure. Confounding variables were adjusted for in the analysis of the articles, but they may still contribute to the risk of NTDs. All the studies analyzed pesticide exposure and the relationship with NTDs. However, a more standardized survey would be ideal for better comparisons.

Maternal serum neonicotinoids during early-mid pregnancy and congenital heart diseases in offspring: An exploratory study

Experimental evidence has indicated a correlation between in-utero exposure to neonicotinoid pesticides (NEOs) and adverse birth outcomes in mammals. However, the distribution of NEO exposure during human pregnancy, as well as its association with congenital heart diseases (CHDs), the most common birth defects, are unclear. Our purpose was to explore the distribution of and contributing factors to NEO exposure in pregnant women during early-mid pregnancy and to assess the associations between NEOs and CHDs. This nested case-control study was conducted within an ongoing prospective birth cohort study and enrolled 141 CHD singletons and their 282 individually matched controls. Six "parent" NEOs and three NEO metabolites were measured in maternal serum collected at an average gestational age of 16 weeks, using liquid chromatography-tandem mass spectrometry. Logistic regression was used to quantify the NEOs-CHDs associations and explore potential contributing factors to serum NEO levels in controls. N-desmethyl acetamiprid (N-dm-ACE) and imidacloprid (IMI) were the most frequently detected NEOs, found in 100% and 20% of maternal sera, respectively. We did not find a statistically significant association between total NEOs and overall CHDs. However, there was a trend towards a higher risk of septal defects with greater serum NEOs (ORs ranged from 1.80 to 2.36), especially nitro-containing NEOs represented by IMI. Pregnant women with lower education had elevated serum total NEOs compared to women with higher education (OR = 48.39, 95% CI: 23.48-99.72). Pregnant women were primarily exposed to N-dm-ACE and IMI during early-mid pregnancy. Gestational exposure to NEOs may be associated with an increased risk of septal defects, but the evidence is limited at present. Education is a potential contributing factor to NEO exposure in pregnant women. Larger and more precise studies with longitudinal biospecimen collection, are recommended to validate our exploratory findings.

Maternal environmental, occupational, and urinary metabolite levels of benzene compounds and their association with congenital heart diseases in offspring: a case‒control study in China

The conclusions about the association of maternal pregnancy environment, occupation, and benzene compounds with fetal CHD are not entirely consistent. Eight hundred seven CHD cases and 1008 controls were included in this study. All occupations were classified and coded against the Occupational Classification Dictionary of the People's Republic of China (2015 version). Logistic regressions were used to explore the correlation among environmental factors, occupation types, and CHDs in offspring. We found that living near public facilities and having exposure to chemical reagents and hazardous substances were significant risk factors for CHDs in offspring. We found that offspring of mothers who worked in agriculture and similar work during pregnancy suffered from CHD. The risk of all CHDs in the offspring of pregnant women working in production manufacturing and related work was significantly higher than that in unemployed pregnant women, the risk was also observed in 4 subtypes of CHDs. We compared the concentrations of the five metabolite (MA, mHA, HA, PGA, and SPMA) levels of benzene compounds in the urine of mothers in case and control groups and found no significant differences. Our study suggests that maternal exposure during pregnancy and certain environmental and occupational conditions are risk factors for CHD in offspring, but did not support an association between concentrations of metabolites of benzene compounds in the urine of pregnant women and CHDs in their offspring.

Pesticide Exposure of Residents Living in Wine Regions: Protocol and First Results of the Pestiprev Study

The PESTIPREV study has been designed to investigate residential exposure to pesticides applied to vines and ultimately propose mitigation measures. A feasibility study was carried out to validate a protocol for measuring six pesticides in three houses located near vineyards in July 2020. Samples included indoor and outdoor surfaces sampled with wipes (n = 214), patches on the resident's skin (n = 7), hand or foot washing (n = 5), and pets sampled using wipes (n = 2). Limits of quantification for wipes ranged between 0.02 ng for trifloxystrobin and 1.50 ng for pyraclostrobin. Tebuconazole and trifloxystrobin were quantified in nearly 100% of the surface samples, whereas the other fungicides were less frequently found (from 39.7% for pyraclostrobin to 55.1% for boscalid). The median surface loadings ranged from 3.13 ng/m² for benalaxyl to 82.48 ng/m² for cymoxanil. The pesticides most frequently quantified in hand washing, patch samples, and pet wipes were the same as those quantified on surfaces. Finally, the analyses proved to be successful. The tools developed to collect information on determinants were well completed. The protocol was well received by the participants and appeared to be feasible and relevant to the objective of the PESTIPREV study, although some improvements have been identified. It was applied on a larger scale in 2021 to study the determinants of pesticide exposure.

Environmental Exposures and Congenital Heart Disease

Congenital heart disease (CHD) is the most common congenital abnormality worldwide, affecting 8 to 12 infants per 1000 births globally and causing >40% of prenatal deaths. However, its causes remain mainly unknown, with only up to 15% of CHD cases having a determined genetic cause. Exploring the complex relationship between genetics and environmental exposures is key in understanding the multifactorial nature of the development of CHD. Multiple population-level association studies have been conducted on maternal environmental exposures and their association with CHD, including evaluating the effect of maternal disease, medication exposure, environmental pollution, and tobacco and alcohol use on the incidence of CHD. However, these studies have been done in a siloed manner, with few examining the interplay between multiple environmental exposures. Here, we broadly and qualitatively review the current literature on maternal and paternal prenatal exposures and their association with CHD. We propose using the framework of the emerging field of the exposome, the environmental complement to the genome, to review all internal and external prenatal environmental exposures and identify potentiating or alleviating synergy between exposures. Finally, we propose mechanistic pathways through which susceptibility to development of CHD may be induced via the totality of prenatal environmental exposures, including the interplay between placental and cardiac development and the internal vasculature and placental morphology in early stages of pregnancy.

Risk of congenital heart disease due to exposure to common electrical appliances during early pregnancy: a case-control study

To examine the association between exposure to common electrical appliances in early pregnancy and congenital heart disease (CHD). A case-control study of 2339 participants was conducted in six hospitals in Xi'an, Shaanxi Province, Northwest China from 2014 to 2016. All infants with CHD were diagnosed according to ICD-10 classification. Selected controls consisted of newborns from the same hospital, without any birth defects, and 1:3 matched by birthdate. We conducted personal interviews with the mothers to gather information on any exposure to electrical appliances during pregnancy. Multivariate logistic regression was used to estimate the effects of exposure to common electrical appliances on CHD. We observed that the mothers exposed to computers (OR: 1.33, 95% CI: 1.03, 1.71), induction cookers (OR: 2.79, 95% CI: 2.19, 3.55), and microwave ovens (OR: 1.53, 95% CI: 1.01, 2.31) during early pregnancy were more likely to give birth to infants with CHD. Mothers who wore radiation protection suits (OR: 0.67, 95% CI: 0.52, 0.87) during early pregnancy decreased the risk of CHD in their neonate. There was an interaction for induction cooker exposure with wore radiation protection suits on CHD (RERI: - 1.44, 95% CI: - 2.48, - 0.39; S: 0.37, 95% CI: 0.16, 0.84; AP: - 0.79, 95% CI: - 1.53, - 0.05). Our study confirmed that exposure to some electrical appliances was associated with a higher risk of CHD, and wearing a radiation protection suit was associated with a lower risk of CHD. Women should therefore reduce the usage of electrical appliances before and during pregnancy.

Parental occupational exposure and congenital heart diseases in a Hungarian case-control study

Purpose

Our study aimed to explore the effect of parental occupational exposure to endocrine disrupting chemicals (EDCs) on the development of congenital heart diseases (CHDs) in the offspring, and to compare job-exposure matrix (JEM)-assessed and self-reported occupational exposures with each other.

Methods

Live-born infants born in 2007–2008 were selected from the population-based Hungarian Case–Control Surveillance of Congenital Abnormalities Study. 577 cases with any CHDs were compared to 1731 matched controls. Parental periconceptional occupational exposure to EDCs was assessed by a JEM and by questionnaire-based self-reporting of parents. Multivariate conditional logistic regression analyses were conducted to explore associations between parental occupational exposure to EDCs and the entire spectrum of CHDs and by CHD subtypes in the offspring. Kappa statistics were also performed to determine the consistency among JEM-assessed and self-reported occupational exposure of parents.

Results

JEM-assessed paternal exposure to polychlorinated organic substances, phthalates, biphenolic compounds, and solvents were significantly associated with the entire spectrum of CHDs. Ventricular septal defects were significantly associated with paternal self-reported exposure to pesticides, while atrial septal defects were significantly associated to paternal JEM-assessed phthalate exposure. Paternal solvent exposure was significantly associated with atrial septal defects and right ventricle outflow tract obstructions. JEM-assessed and self-reported exposures to pesticides, heavy metals, and solvents exhibited poor agreement for mothers and slight agreement for fathers.

Conclusion

Even though parental occupational exposure to EDCs seems to have a minor impact on the occurrence of CHDs, the results of biological and environmental monitoring should be taken into consideration as well.

Maternal occupational exposure and congenital heart defects in offspring

Objectives Congenital heart defects (CHD) are the most prevalent congenital anomalies. This study aims to examine the association between maternal occupational exposures to organic and mineral dust, solvents, pesticides, and metal dust and fumes and CHD in the offspring, assessing several subgroups of CHD. Methods For this case-control study, we examined 1174 cases with CHD from EUROCAT Northern Netherlands and 5602 controls without congenital anomalies from the Lifelines cohort study. Information on maternal jobs held early in pregnancy was collected via self-administered questionnaires, and job titles were linked to occupational exposures using a job exposure matrix. Results An association was found between organic dust exposure and coarctation of aorta [adjusted odds ratio (OR _adj) 1.90, 95% confidence interval (CI) 1.01-3.59] and pulmonary (valve) stenosis in combination with ventricular septal defect (OR _adj2.68, 95% CI 1.07-6.73). Mineral dust exposure was associated with increased risk of coarctation of aorta (OR _adj2.94, 95% CI 1.21-7.13) and pulmonary valve stenosis (OR _adj1.99, 95% CI 1.10-3.62). Exposure to metal dust and fumes was infrequent but was associated with CHD in general (OR _adj2.40, 95% CI 1.09-5.30). Exposure to both mineral dust and metal dust and fumes was associated with septal defects (OR _adj3.23, 95% CI 1.14-9.11). Any maternal occupational exposure was associated with a lower risk of aortic stenosis (OR _adj0.32, 95% CI 0.11-0.94). Conclusions Women should take preventive measures or avoid exposure to mineral and organic dust as well as metal dust and fumes early in pregnancy as this could possibly affect foetal heart development.

Prevalence rates study of selected isolated non-Mendelian congenital anomalies in the Hutterite population of Alberta, 1980-2016

A study of the prevalence rates for selected isolated non-Mendelian congenital anomalies in the Hutterite Brethren of Alberta, Canada was undertaken to further examine longitudinal data in this isolated community that was last reported in 1985 (Lowry et al., 1985), although there are numerous publications on recessive disorders (Boycott et al., 2008; Triggs-Raine et al., 2016). Cases were ascertained from the Alberta Congenital Anomaly Surveillance System for the years 1997-2016. Since our initial results showed some surprising findings in the Hutterite Brethren, such as zero cases of spina bifida, cleft lip and palate, gastroschisis, and omphalocele, and a significant excess of cases with hypospadias, we extended the study to prior years (1980-1996) for selected anomalies. For the extended study period (1980-2016), there was a significant increased prevalence of hypospadias, tetralogy of Fallot and tricuspid atresia in the Hutterite population, and although not statistically significant, zero cases of cleft lip with cleft palate, gastroschisis and omphalocele were confirmed. Further research is needed to determine the precise effects of rural environmental exposures, lifestyle factors, and genetic associations for selected multifactorial congenital anomalies.

Malformações congênitas e uso de agrotóxicos no município de Giruá, RS

RESUMO O objetivo deste estudo foi relacionar o uso de agrotóxicos com a ocorrência de malformações congênitas no município de Giruá (RS), bem como determinar os fatores de risco associados. A pesquisa é de abordagem quantitativa, do tipo descritivo-exploratória, realizada durante o primeiro semestre de 2019. O estudo foi conduzido em duas etapas: (a) associação da ocorrência de malformações com o uso de agrotóxicos, que foi calculada por meio dos Odds Ratios, sendo o Intervalo de Confiança (IC) adotado para as amostras de 95%; e (b) determinação dos fatores de risco associados, em que foi realizada uma entrevista com agricultores residentes no município. Percebe-se que as taxas de malformações congênitas do município de Giruá são superiores à média do estado para o mesmo período. Há probabilidade de que a ocorrência de malformações no município esteja associada ao uso de agrotóxicos, pois todos os valores dos Odds Ratios foram maiores que um. Os fatores de risco identificados foram baixa escolaridade, classe toxicológica e princípios ativos, uso inadequado de Equipamentos de Proteção Individual (EPIs), número de pessoas com diagnóstico de intoxicação ou que relataram algum sinal ou sintoma associado e armazenamento dos produtos.

Associations between cumulative environmental quality and ten selected birth defects in Texas

BACKGROUND

Causes of most birth defects are largely unknown. Genetics, maternal factors (e.g., age, smoking) and environmental exposures have all been linked to some birth defects, including neural tube, oral cleft, limb reduction, and gastroschisis; however, the contribution of cumulative exposures across several environmental domains in association with these defects is not well understood.

METHODS

The Environmental Quality Index (EQI) and its domains (air, water, land, sociodemographic, built) were used to estimate county-level cumulative environmental exposures from 2006-2010 and matched to birth defects identified from Texas Birth Defects Registry and live birth records from births in years 2007-2010 (N = 1,610,709). Poisson regression models estimated prevalence ratios (PR) and 95% confidence intervals (CI) for associations between 10 birth defects and the EQI.

RESULTS

We observed some positive associations between worst environmental quality and neural tube, anencephaly, spina bifida, oral cleft, cleft palate, cleft lip with and without cleft palate, and gastroschisis [PR range: 1.12-1.55], but near null associations with limb reduction defects. Among domain specific results, we observed the strongest positive associations with the sociodemographic domain across birth defects but varied positive associations among the air and water domains, and negative or null associations with the land and built domains. Overall, few exposure-response patterns were evident.

CONCLUSIONS

Our results highlight the complexities of cumulative, simultaneous environmental exposures in the prevalence rates of 10 selected birth defects. We were able to explore the impact of overall and domain specific environmental quality on birth defects and identify potential domain specific drivers of these associations.

Congenital anomalies in the offspring of occupationally exposed mothers: a systematic review and meta-analysis of studies using expert assessment for occupational exposures

STUDY QUESTION

Is there an association between maternal occupational exposure to solvents, pesticides and metals as assessed by expert-based assessment and congenital anomalies in the offspring?

SUMMARY ANSWER

There is an association between maternal occupational exposure to solvents and congenital anomalies in the offspring, including neural tube defects, congenital heart defects and orofacial clefts.

WHAT IS KNOWN ALREADY

One important environmental risk factor for development of congenital anomalies is maternal occupational exposure to chemicals in the workplace prior to and during pregnancy. A number of studies have assessed the association with often conflicting results, possibly due to different occupational exposure assessing methods.

STUDY DESIGN, SIZE, DURATION

For this systematic review with meta-analysis, the search terms included maternal occupation, exposure, congenital anomalies and offspring. Electronic databases MEDLINE and EMBASE were searched for English studies up to October 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Two reviewers independently screened all citations identified by the search. Case-control studies and cohort studies were included if (I) they reported on the association between maternal occupational exposure to solvents, pesticides or metals and congenital anomalies, and (II) assessment of occupational exposure was performed by experts. Data on study characteristics, confounders and odds ratios (ORs) were extracted from the included studies for four subgroups of congenital anomalies. Methodological quality was assessed using the Newcastle-Ottawa Scale. In the meta-analysis, random effects models were used to pool estimates.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 2806 titles and abstracts and 176 full text papers were screened. Finally, 28 studies met the selection criteria, and 27 studies could be included in the meta-analysis. Our meta-analysis showed that maternal occupational exposure to solvents was associated with neural tube defects (OR: 1.51, 95%CI: 1.09–2.09) and congenital heart defects (OR: 1.31, 95%CI:1.06–1.63) in the offspring. Also maternal occupational exposure to glycol ethers, a subgroup of solvents, was associated with neural tube defects (OR: 1.93, 95%CI: 1.17–3.18) and orofacial clefts (OR: 1.95, 95%CI: 1.38–2.75) in the offspring. Only one study investigated the association between maternal occupational exposure to solvents and hypospadias and found an association (OR: 3.63, 95%CI: 1.94–7.17). Results of the included studies were consistent. In our meta-analysis, we found no associations between occupational exposure to pesticides or metals and congenital anomalies in the offspring.

LIMITATIONS, REASONS FOR CAUTION

A limited number of studies was included, which made it impossible to calculate pooled estimates for all congenital anomalies, analyse individual chemicals or calculate exposure–response relations. Bias could have been introduced because not all included studies corrected for potentially confounding factors.

WIDER IMPLICATIONS OF THE FINDINGS

Employers and female employees should be aware of the possible teratogenic effects of solvent exposure at the workplace. Therefore, is it important that clinicians and occupational health specialist provide women with preconception advice on occupational solvent exposure, to reduce the congenital anomaly risk.

STUDY FUNDING/COMPETING INTEREST(S)

NSp was paid by the Graduate School of Medical Sciences (MD/PhD program), UMCG, Groningen, the Netherlands. EUROCAT Northern Netherlands is funded by the Dutch Ministry of Health, Welfare and Sports. There are no competing interests.

REGISTRATION NUMBER

CRD42017053943.

Associations between fine particulate matter, extreme heat events, and congenital heart defects

Previous research reports associations between air pollution measured during pregnancy and the occurrence of congenital heart defects (CHDs) in offspring. The objective of this research was to assess if exposure to extreme heat events (EHEs) during pregnancy may modify this association.

METHODS

The study population consisted of 4,033 controls and 2,632 cases with dates of delivery between 1999 and 2007 who participated in the National Birth Defects Prevention Study, a multi-site case-control study in the United States. Daily data from the closest stationary fine particulate matter (PM2.5) monitor within 50 km from the maternal residence were averaged across weeks 3-8 post-conception. EHEs were defined as maximum ambient temperature in the upper 95th percentile for at least 2 consecutive days or the upper 90th percentile for 3 consecutive days. Logistic regression models were adjusted for maternal age, ethnicity, education, and average humidity. Relative excess risks due to interaction (RERI) were calculated.

RESULTS

Compared with women with low PM2.5 exposure and no exposure to an EHE, the odds of a ventricular septal defect in offspring associated with high PM2.5 exposure was elevated only among women who experienced an EHE (odds ratio [OR] 2.14 95% confidence interval [CI] 1.19, 3.38 vs. OR 0.97 95% CI 0.49, 1.95; RERI 0.82 95% CI -0.39, 2.17). The majority of observed associations and interactions for other heart defects were null and/or inconclusive due to lack of precision.

CONCLUSIONS

This study provides limited evidence that EHEs may modify the association between prenatal exposure to PM2.5 and CHD occurrence.

Risk factors associated with the development of double-inlet ventricle congenital heart disease

BACKGROUND

Congenital heart disease (CHD) is the most common birth defect group and a significant contributor to neonatal and infant death. CHD with single ventricle anatomy, including hypoplastic left heart syndrome (HLHS), tricuspid atresia (TA), and various double-inlet ventricle (DIV) malformations, is the most complex with the highest mortality. Prenatal risk factors associated with HLHS have been studied, but such data for DIV are lacking.

METHODS

We analyzed DIV cases and nonmalformed controls in the National Birth Defects Prevention Study, a case-control, multicenter population-based study of birth defects. Random forest analysis identified potential predictor variables for DIV, which were included in multivariable models to estimate effect magnitude and directionality.

RESULTS

Random forest analysis identified pre-pregnancy diabetes, history of maternal insulin use, maternal total lipid intake, paternal race, and intake of several foods and nutrients as potential predictors of DIV. Logistic regression confirmed pre-pregnancy diabetes, maternal insulin use, and paternal race as risk factors for having a child with DIV. Additionally, higher maternal total fat intake was associated with a reduced risk.

CONCLUSIONS

Maternal pre-pregnancy diabetes and history of insulin use were associated with an increased risk of having an infant with DIV, while maternal lipid intake had an inverse association. These novel data provide multiple metabolic pathways for investigation to identify better the developmental etiologies of DIV and suggest that public health interventions targeting diabetes prevention and management in women of childbearing age could reduce CHD risk.

Environmental Contaminants and Congenital Heart Defects: A Re-Evaluation of the Evidence

Congenital heart defects (CHDs) are a common birth defect of largely unknown etiology, with high fetal and neonatal mortality. A review of CHDs and environmental contaminant exposure found that meta-analyses showed only modest associations for smoking, vehicle exhaust components, disinfectant by-products and proximity to incinerators, with stronger results from the newer, larger and better quality studies masked by the typical absence of effect in older studies. Recent studies of exposure to agricultural pesticides, solvents, metals and landfill sites also showed associations. Certain contaminants have been associated with certain CHDs, with septal defects being the most common. Frequent methodological problems include failure to account for potential confounders or maternal/paternal preconception exposure, differences in diagnosing, defining and classifying CHDs, grouping of defects to increase power, grouping of contaminants with dissimilar mechanisms, exclusion of pregnancies that result in death or later life diagnosis, and the assumption that maternal residence at birth is the same as at conception. Furthermore, most studies use measurement estimates of one exposure, ignoring the many additional contaminant exposures in daily life. All these problems can distort and underestimate the true associations. Impaired methylation is a common mechanism, suggesting that supplementary folate may be protective for any birth defect.

sox9b is required in cardiomyocytes for cardiac morphogenesis and function

The high mobility group transcription factor SOX9 is expressed in stem cells, progenitor cells, and differentiated cell-types in developing and mature organs. Exposure to a variety of toxicants including dioxin, di(2-ethylhexyl) phthalate, 6:2 chlorinated polyfluorinated ether sulfonate, and chlorpyrifos results in the downregulation of tetrapod Sox9 and/or zebrafish sox9b. Disruption of Sox9/sox9b function through environmental exposures or genetic mutations produce a wide range of phenotypes and adversely affect organ development and health. We generated a dominant-negative sox9b (dnsox9b) to inhibit sox9b target gene expression and used the Gal4/UAS system to drive dnsox9b specifically in cardiomyocytes. Cardiomyocyte-specific inhibition of sox9b function resulted in a decrease in ventricular cardiomyocytes, an increase in atrial cardiomyocytes, hypoplastic endothelial cushions, and impaired epicardial development, ultimately culminating in heart failure. Cardiomyocyte-specific dnsox9b expression significantly reduced end diastolic volume, which corresponded with a decrease in stroke volume, ejection fraction, and cardiac output. Further analysis of isolated cardiac tissue by RT-qPCR revealed cardiomyocyte-specific inhibition of sox9b function significantly decreased the expression of the critical cardiac development genes nkx2.5, nkx2.7, and myl7, as well as c-fos, an immediate early gene necessary for cardiomyocyte progenitor differentiation. Together our studies indicate sox9b transcriptional regulation is necessary for cardiomyocyte development and function.

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.

Estimated Maternal Pesticide Exposure from Drinking Water and Heart Defects in Offspring

Our objective was to examine the relationship between estimated maternal exposure to pesticides in public drinking water and the risk of congenital heart defects (CHD). We used mixed-effects logistic regression to analyze data from 18,291 nonsyndromic cases with heart defects from the Texas Birth Defects Registry and 4414 randomly-selected controls delivered in Texas from 1999 through 2005. Water district-level pesticide exposure was estimated by linking each maternal residential address to the corresponding public water supply district’s measured atrazine levels. We repeated analyses among independent subjects from the National Birth Defects Prevention Study (NBDPS) (1620 nonsyndromic cases with heart defects and 1335 controls delivered from 1999 through 2005). No positive associations were observed between high versus low atrazine level and eight CHD subtypes or all included heart defects combined. These findings should be interpreted with caution, in light of potential misclassification and relatively large proportions of subjects with missing atrazine data. Thus, more consistent and complete monitoring and reporting of drinking water contaminants will aid in better understanding the relationships between pesticide water contaminants and birth defects.

Associação entre malformações congênitas e a utilização de agrotóxicos em monoculturas no Paraná, Brasil

RESUMO O objetivo deste artigo é analisar a associação entre o uso de agrotóxicos e as malformações congênitas em municípios com maior exposição aos agrotóxicos no estado do Paraná, Brasil, entre 1994 e 2014. Estudo de abordagem quantitativa, ecológico, conduzido com informações dos nascidos vivos (Sinasc/Ministério da Saúde), elaborando-se taxas de malformações ocorridas de 1994 a 2003 e de 2004 a 2014. Foi encontrada uma tendência crescente nas taxas de malformação congênita no estado do Paraná, com destaque aos municípios de Francisco Beltrão e Cascavel. Essas malformações congênitas podem ser advindas da exposição da população a agrotóxicos, sendo uma sinalização expressiva nos problemas de saúde pública.

Residential agricultural pesticide exposures and risks of selected birth defects among offspring in the San Joaquin Valley of California

BACKGROUND

We examined associations of birth defects with residential proximity to commercial agricultural pesticide applications in California. Subjects included 367 cases representing five types of birth defects and 785 nonmalformed controls born 1997 to 2006.

METHODS

Associations with any versus no exposure to physicochemical groups of pesticides and specific chemicals were assessed using logistic regression adjusted for covariates. Overall, 46% of cases and 38% of controls were classified as exposed to pesticides within a 500 m radius of mother's address during a 3-month periconceptional window.

RESULTS

We estimated odds ratios (ORs) for 85 groups and 95 chemicals with five or more exposed cases and control mothers. Ninety-five percent confidence intervals (CI) excluded 1.0 for 11 ORs for groups and 22 ORs for chemicals, ranging from 1.9 to 3.1 for groups and 1.8 to 4.9 for chemicals except for two that were <1 (noted below).

CONCLUSION

For groups, these ORs were for anotia/microtia (n = 95 cases) and dichlorophenoxy acids/esters and neonicotinoids; anorectal atresia/stenosis (n = 77) and alcohol/ethers and organophosphates (these ORs were < 1.0); transverse limb deficiencies (n = 59) and dichlorophenoxy acids/esters, petroleum derivatives, and triazines; and craniosynostosis (n = 79) and alcohol/ethers, avermectins, neonicotinoids, and organophosphates. For chemicals, ORs were: anotia/microtia and five pesticides from the groups dichlorophenoxy acids/esters, copper-containing compounds, neonicotinoids, organophosphates, and triazines; transverse limb deficiency and six pesticides - oxyfluorfen and pesticides from the groups copper-containing compounds, 2,6-dinitroanilines, neonicotinoids, petroleum derivatives and polyalkyloxy compounds; craniosynostosis and 10 pesticides - oxyfluorfen and pesticides from the groups alcohol/ethers, avermectins, n-methyl-carbamates, neonicotinoids, ogranophosphates (two chemicals), polyalkyloxy compounds (two chemicals), and pyrethroids; and congenital diaphragmatic hernia (n = 62) and a copper-containing compound.