Early exposure to mercury and cardiovascular function of seven-year old children in Guadeloupe (French West Indies)

BACKGROUND

The cardiotoxicity of prenatal exposure to mercury has been suggested in populations having regular contaminated seafood intake, though replications in the literature are inconsistent.

METHODS

The Timoun Mother-Child Cohort Study was set up in Guadeloupe, an island in the Caribbean Sea where seafood consumption is regular. At seven years of age, 592 children underwent a medical examination, including cardiac function assessment. Blood pressure (BP) was taken using an automated blood pressure monitor, heart rate variability (HRV, 9 parameters) and electrocardiogram (ECG) characteristics (QT, T-wave parameters) were measured using Holter cardiac monitoring during the examination. Total mercury concentrations were measured in cord blood at birth (median = 6.6 μg/L, N = 399) and in the children's blood at age 7 (median = 1.7 μg/L, N = 310). Adjusted linear and non-linear modelling was used to study the association of each cardiac parameter with prenatal and childhood exposures. Sensitivity analyses included co-exposures to lead and cadmium, adjustment for maternal seafood consumption, selenium and polyunsaturated fatty acids (n3-PUFAs), and for sporting activity.

RESULTS

Higher prenatal mercury was associated with higher systolic BP at 7 years of age (βlog2 = 1.02; 95% Confidence Interval (CI) = 0.10, 1.19). In boys, intermediate prenatal exposure was associated with reduced overall HRV and parasympathetic activity, and longer QT was observed with increasing prenatal mercury (βlog2 = 4.02; CI = 0.48, 7.56). In girls, HRV tended to increase linearly with prenatal exposure, and no association was observed with QT-wave related parameters. Mercury exposure at 7 years was associated with decreased BP in girls (βlog2 = -1.13; CI = -2.22, -0.004 for diastolic BP). In boys, the low/high-frequency (LF/HF) ratio increased for intermediate levels of exposure.

CONCLUSION

Our study suggests sex-specific and non-monotonic modifications in some cardiac health parameters following prenatal exposure to mercury in pre-pubertal children from an insular fish-consuming population.

Scannotation: A Suspect Screening Tool for the Rapid Pre-Annotation of the Human LC-HRMS-Based Chemical Exposome

In an increasingly chemically polluted environment, rapidly characterizing the human chemical exposome (i.e., chemical mixtures accumulating in humans) at the population scale is critical to understand its impact on health. High-resolution mass spectrometry (HRMS) profiling of complex biological matrices can theoretically provide a comprehensive picture of chemical exposures. However, annotating the detected chemical features, particularly low-abundant ones, remains a significant obstacle to implementing such approaches at a large scale. We present Scannotation (https://github.com/scannotation/Scannotation_software), an automated and user-friendly suspect screening tool for the rapid pre-annotation of HRMS preprocessed data sets. This software tool combines several MS1 chemical predictors, i.e., m/z, experimental and predicted retention times, isotopic patterns, and neutral loss patterns, to score the proximity between features and suspects, thus efficiently prioritizing tentative annotations to verify. Scannotation and MS-DIAL4 were used to annotate blood serum samples of 75 Breton adolescents. Scannotation's combination of MS1-based chemical predictors allowed us to annotate 89 chemically diverse environmental compounds with high confidence (confirmed by MS2 when available). These compounds included 62% of emerging molecules, for which no toxicological or human biomonitoring data are reported in the literature. The complementarity observed with MS-DIAL4 results demonstrates the relevance of Scannotation for the efficient pre-annotation of large-scale exposomics data sets.

Prenatal Exposure to Perfluoroalkyl Substances and Child Behavior at Age 12: A PELAGIE Mother-Child Cohort Study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are chemical substances spread throughout the environment worldwide. Exposure during pregnancy represents a specific window of vulnerability for child health.

OBJECTIVE

Our objective was to assess the impact of prenatal exposure to multiple PFAS on emotional and behavioral functions in 12-y-old children.

METHOD

In the PELAGIE mother-child cohort (France), prenatal exposure to nine PFAS was measured from concentrations in cord serum samples. Behavior was assessed at age 12 y using the parent-reported Strengths and Difficulties Questionnaire (SDQ) and the self-reported Dominic Interactive for Adolescents (DIA) for 444 children. Associations were estimated using negative binomial models for each PFAS. Bayesian kernel machine regression (BKMR) models were performed to assess the exposure mixture effect on children's behavior.

RESULTS

In our study population, 73% of mothers had spent more than 12 y in education. Higher scores on SDQ externalizing subscale were observed with increasing cord-serum concentration of perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) [adjusted mean ratio ( aMR ) = 1.18 , 95% confidence interval (CI): 1.03, 1.34, and aMR = 1.14 (95% CI: 1.00, 1.29) for every doubling of concentration, respectively]. Results for the hyperactivity score were similar [aMR = 1.20 (95% CI: 1.04, 1.40) and aMR = 1.18 (95% CI: 1.02, 1.36), respectively]. With regard to major depressive disorder and internalizing subscales, perfluorodecanoic acid (PFDA) was associated with higher self-reported DIA scores [aMR = 1.14 (95% CI: 1.01, 1.27) and aMR = 1.11 (95% CI: 1.02, 1.21), respectively]. In terms of the anxiety subscale, PFDA and PFNA were associated with higher scores [aMR = 1.11 (95% CI: 1.02, 1.21) and aMR = 1.10 (95% CI: 1.01, 1.19), respectively]. Concurrent increases in the PFAS concentrations included in the BKMR models showed no change in the SDQ externalizing and DIA internalizing subscales scores.

CONCLUSION

Prenatal exposure to PFNA and PFOA were associated with increasing scores for measures of externalizing behaviors, specifically hyperactivity. We also identified associations between PFNA and PFDA prenatal exposure levels and increasing scores related to internalizing behaviors (general anxiety and major depressive disorder), which adds to the as yet sparse literature examining the links between prenatal exposure to PFAS and internalizing disorders. https://doi.org/10.1289/EHP12540.

Prenatal and childhood exposure to ambient air pollution and cognitive function in school-age children: Examining sensitive windows and sex-specific associations

BACKGROUND

Combined effect of both prenatal and early postnatal exposure to ambient air pollution on child cognition has rarely been investigated and periods of sensitivity are unknown. This study explores the temporal relationship between pre- and postnatal exposure to PM10, PM2.5, NO2 and child cognitive function.

METHODS

Using validated spatiotemporally resolved exposure models, pre- and postnatal daily PM2.5, PM10 (satellite based, 1 km resolution) and NO2 (chemistry-transport model, 4 km resolution) concentrations at the mother's residence were estimated for 1271 mother-child pairs from the French EDEN and PELAGIE cohorts. Scores representative of children's General, Verbal and Non-Verbal abilities at 5-6 years were constructed based on subscale scores from the WPPSI-III, WISC-IV or NEPSY-II batteries, using confirmatory factor analysis (CFA). Associations of both prenatal (first 35 gestational weeks) and postnatal (60 months after birth) exposure to air pollutants with child cognition were explored using Distributed Lag Non-linear Models adjusted for confounders.

RESULTS

Increased maternal exposure to PM10, PM2.5 and NO2, during sensitive windows comprised between the 15th and the 33rd gestational weeks, was associated with lower males' General and Non-verbal abilities. Higher postnatal exposure to PM2.5 between the 35th and 52nd month of life was associated with lower males' General, Verbal and Non-verbal abilities. Some protective associations were punctually observed for the very first gestational weeks or months of life for both males and females and the different pollutants and cognitive scores.

DISCUSSION

These results suggest poorer cognitive function at 5-6 years among males following increased maternal exposure to PM10, PM2.5 and NO2 during mid-pregnancy and child exposure to PM2.5 around 3-4 years. Apparent protective associations observed are unlikely to be causal and might be due to live birth selection bias, chance finding or residual confounding.

Screen Time at 6 Years Old and Visual Function in Early Adolescence

Excessive screen time has been linked to adverse health outcomes in children, including vision-related problems such as myopia. However, very few studies have evaluated the effect of moderate screen exposure on the development of visual functions. This study aimed to examine the association between screen time during middle childhood and color discrimination, contrast sensitivity, and short-range visual acuity in 12-year-old children (n = 305) from the mother-child PELAGIE cohort (France) for the whole sample and for boys and girls separately. Visual functions were assessed using the Freiburg Acuity and Contrast Test and an adapted version of the Cambridge Color Test. Screen exposure was documented using a parent self-report questionnaire. Regression models showed that screen exposure at 6 years of age was significantly associated with higher contrast sensitivity across the entire sample at 12 years of age. However, when controlling for covariates, this association remained statistically significant in girls only. Sex-stratified analyses also showed that moderate screen exposure was linked to improved tritan-axis color vision in boys only. These findings suggest that moderate screen exposure in middle childhood is not harmful to visual function development and as such, provide new insights into the impact of digital technology on children's visual health and development.

Prenatal exposure to persistent organic pollutants and molar-incisor hypomineralization among 12-year-old children in the French mother-child cohort PELAGIE

BACKGROUND

Exceptional episodes of exposure to high levels of persistent organic pollutants have already been associated with developmental defects of enamel among children, but knowledge is still scarce concerning the contribution of background levels of environmental contamination.

METHODS

Children of the French PELAGIE mother-child cohort were followed from birth, with collection of medical data and cord blood samples that were used to measure polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), and perfluorinated alkyl substances (PFASs). At 12 years of age, molar-incisor hypomineralization (MIH) and other enamel defects (EDs) were recorded for 498 children. Associations were studied using logistic regression models adjusted for potential prenatal confounders.

RESULTS

An increasing log-concentration of β-HCH was associated with a reduced risk of MIH and EDs (OR = 0.55; 95% CI, 0.32-0.95, and OR = 0.65; 95% CI, 0.43-0.98, respectively). Among girls, intermediate levels of p,p'-DDE were associated with a reduced risk of MIH. Among boys, we observed an increased risk of EDs in association with intermediate levels of PCB 138, PCB 153, PCB 187, and an increased risk of MIH with intermediate levels of PFOA and PFOS.

CONCLUSIONS

Two OCs were associated with a reduced risk of dental defects, whereas the associations between PCBs and PFASs and EDs or MIH were generally close to null or sex-specific, with an increased risk of dental defects in boys. These results suggest that POPs could impact amelogenesis. Replication of this study is required and the possible underlying mechanisms need to be explored.

Prenatal exposure to multiple persistent organic pollutants in association with adiposity markers and blood pressure in preadolescents

BACKGROUND

Several studies have reported that prenatal exposure to some persistent organic pollutants (POPs) is associated with higher adiposity in childhood. Few studies have assessed whether this finding persists into adolescence, and few have considered exposure to POPs as a mixture. This study aims to assess the association between prenatal exposure to multiple POPs and adiposity markers and blood pressure in preadolescents.

METHODS

This study included 1667 mother-child pairs enrolled in the PELAGIE (France) and the INMA (Spain) mother-child cohorts. Three polychlorobiphenyls (PCB 138, 153 and 180, treated as a sum of PCBs) and three organochlorine pesticides (p,p'-Dichlorodiphenyldichloroethylene [p,p'-DDE], β-hexachlorocyclohexane [β-HCH], and hexachlorobenzene [HCB]) were assessed in maternal or cord serum. Body mass index z-score (zBMI), abdominal obesity (waist-to-height ratio > 0.5), percentage of fat mass, and blood pressure (mmHg) were measured at around 12 years of age. Single-exposure associations were studied using linear or logistic regressions, and the POP mixture effect was evaluated using quantile G-computation (qgComp) and Bayesian Kernel Machine Regression (BKMR). All models were adjusted for potential confounders and performed for boys and girls together and separately.

RESULTS

Prenatal exposure to the POP mixture was associated with higher zBMI (beta [95 % CI] of the qgComp = 0.15 [0.07; 0.24]) and percentage of fat mass (0.83 [0.31; 1.35]), with no evidence of sex-specific association. These mixture effects were also statistically significant using BKMR. These associations were driven mainly by exposure to HCB and, to a lesser extent, to β-HCH. In addition, the single-exposure models showed an association between β-HCH and p,p'-DDE and higher systolic blood pressure, especially in girls (p,p'-DDE for girls = 1.00 [0.15; 1.86]). No significant associations were found for PCBs.

CONCLUSION

This study suggests that prenatal exposure to POPs, particularly organochlorine pesticides, remains associated with unfavorable cardiometabolic health up to the age of 12.

Genome-wide analysis of sex-specific differences in the mother-child PELAGIE cohort exposed to organophosphate metabolites

In recent decades, the detrimental effects of environmental contaminants on human health have become a serious public concern. Organophosphate (OP) pesticides are widely used in agriculture, and the negative impacts of OP and its metabolites on human health have been demonstrated. We hypothesized that exposure to OPs during pregnancy could impose damaging effects on the fetus by affecting various processes. We analyzed sex-specific epigenetic responses in the placenta samples obtained from the mother-child PELAGIE cohort. We assayed the telomere length and mitochondrial copy numbers using genomic DNA. We analyzed H3K4me3 by using chromatin immunoprecipitation followed by qPCR (ChIP‒qPCR) and high-throughput sequencing (ChIP-seq). The human study was confirmed with mouse placenta tissue analysis. Our study revealed a higher susceptibility of male placentas to OP exposure. Specifically, we observed telomere length shortening and an increase in γH2AX levels, a DNA damage marker. We detected lower histone H3K9me3 occupancy at telomeres in diethylphosphate (DE)-exposed male placentas than in nonexposed placentas. We found an increase in H3K4me3 occupancy at the promoters of thyroid hormone receptor alpha (THRA), 8-oxoguanine DNA glycosylase (OGG1) and insulin-like growth factor (IGF2) in DE-exposed female placentas. H3K4me3 occupancy at PPARG was increased in both male and female placentas exposed to dimethylphosphate (DM). The genome-wide sequencing of selected samples revealed sex-specific differences induced by DE exposure. Specifically, we found alterations in H3K4me3 in genes related to the immune system in female placenta samples. In DE-exposed male placentas, a decrease in H3K4me3 occupancy at development-related, collagen and angiogenesis-related genes was observed. Finally, we observed a high number of NANOG and PRDM6 binding sites in regions with altered histone occupancy, suggesting that the effects were possibly mediated via these factors. Our data suggest that in utero exposure to organophosphate metabolites affects normal placental development and could potentially impact late childhood.

Determination of glyphosate and AMPA in indoor settled dust by hydrophilic interaction liquid chromatography with tandem mass spectrometry and implications for human exposure

The widespread application of glyphosate leads to significant contamination of outdoor environmental compartments, notably air and soil, which can contaminate indoor air and dust. This study assessed the contamination of indoor household dust for the first time in France and potential exposure to glyphosate through the inadvertent ingestion of dust. A specific and new analytical method was developed using HILIC MS/MS (hydrophilic interaction liquid chromatography with tandem mass spectrometry) to measure polar pesticides, such as glyphosate, aminomethylphosphonic acid, and glufosinate, in indoor dust, with a low quantification limit (25 ng/g). The dust from vacuum cleaner bags of 60 rural and urban households (Brittany, France) was analyzed. All samples contained glyphosate (median 1675 ng/g for rural dwellings (n = 29), 457 ng/g for urban dwellings (n = 31)), more than 90 % contained aminomethylphosphonic acid, and none contained glufosinate. Concentrations were influenced by the rural or urban setting, the proximity of crops, and the use of weed killers on driveways or lawns. Glyphosate exposure via indoor dust ingestion was < 1 % of both acceptable daily intake and dietary intake. However, the high quantification limit of the glyphosate concentration in the food analysis method probably leads to overestimation of the dose from food.

Prenatal and childhood chlordecone exposure, cognitive abilities and problem behaviors in 7-year-old children: the TIMOUN mother-child cohort in Guadeloupe

BACKGROUND

Chlordecone is a highly persistent organochlorine insecticide that was intensively used in banana fields in the French West Indies, resulting in a widespread contamination. Neurotoxicity of acute exposures in adults is well recognized, and empirical data suggests that prenatal exposure affects visual and fine motor developments during infancy and childhood, with greater susceptibility in boys.

OBJECTIVE

To assess the associations between pre- and postnatal exposures to chlordecone and cognitive and behavioral functions in school-aged children from Guadeloupe.

METHODS

We examined 576 children from the TIMOUN mother-child cohort in Guadeloupe at 7 years of age. Concentrations of chlordecone and other environmental contaminants were measured in cord- and children's blood at age 7 years. Cognitive abilities of children were assessed with the Wechsler Intelligence Scale for Children-IV (WISC-IV), and externalizing and internalizing problem behaviors documented with the Strengths and Difficulties Questionnaire (SDQ) completed by the child's mother. We estimated covariate-adjusted associations between cord- and 7-years chlordecone concentrations and child outcomes using structural equations modeling, and tested effect modification by sex.

RESULTS

Geometric means of blood chlordecone concentrations were 0.13 µg/L in cord blood and 0.06 µg/L in children's blood at age 7 years. A twofold increase in cord blood concentrations was associated with 0.05 standard deviation (SD) (95% Confidence Interval [CI]: 0.0, 0.10) higher internalizing problem scores, whereas 7-years chlordecone concentrations were associated with lower Full-Scale IQ scores (FSIQ) and greater externalized behavioral problem scores. A twofold increase in 7-year chlordecone concentrations was associated with a decrease of 0.67 point (95% CI: -1.13, -0.22) on FSIQ and an increase of 0.04 SD (95% CI: 0.0, 0.07) on externalizing problems. These associations with Cognitive abilities were driven by decreases in perceptive reasoning, working memory and verbal comprehension. Associations between 7-year exposure and perceptive reasoning, working memory, and the FSIQ were stronger in boys, whereas cord blood and child blood associations with internalizing problems were stronger in girls.

CONCLUSIONS

These results suggests that cognitive abilities and externalizing behavior problems at school age are impaired by childhood, but not in utero, exposure to chlordecone, and that prenatal exposure is related to greater internalizing behavioral problems.

Persistent Organic Pollutant Exposure and Thyroid Function among 12-Year-Old Children

INTRODUCTION

Polychlorobiphenyls (PCBs), organochlorine pesticides (OCPs), and per- and polyfluoroalkyl substances (PFASs) are persistent organic pollutants (POPs) having numerous toxicological properties, including thyroid endocrine disruption. Our aim was to assess the impact of POPs on thyroid hormones among 12-year-old children, while taking puberty into consideration.

METHODS

Exposure to 7 PCBs, 4 OCPs, and 6 PFASs (in µg/L), and free tri-iodothyronine (fT3, pg/mL), free thyroxine (fT4, ng/dL), and thyroid-stimulating hormones (TSH, mIU/L) were assessed through blood-serum measurements at age 12 years in 249 boys and 227 girls of the PELAGIE mother-child cohort (France). Pubertal status was clinically rated using the Tanner stages. For each POP, associations were estimated using linear regression, adjusted for potential confounders.

RESULTS

Among boys, hexachlorobenzene and perfluorodecanoic acid were associated with decreased fT3 (log-scale; β [95% confidence interval] = -0.07 [-0.12,-0.02] and β = -0.03 [-0.06,-0.00], respectively). Intermediate levels of perfluorohexanesulfonic acid (PFHxS) and PCB180 were associated, respectively, with increased and decreased fT4. After stratification on pubertal status, PCBs and OCPs were associated with decreased TSH only in the more advanced Tanner stages (3-5) and with decreased fT3 among early Tanner stages (1-2). Among girls, PFHxS was associated with decreased TSH (log-scale; β = -0.15 [-0.29,-0.00]), and perfluorooctanoic acid was associated with decreased fT3 (β2nd_tercile = -0.06 [-0.10,-0.03] and β3rd_tercile = -0.04 [-0.08,-0.00], versus. 1st tercile).

DISCUSSION

This cross-sectional study highlights associations between some POPs and thyroid function disruption, which appears consistent with the literature. Considering that the associations were sex-specific and moderated by pubertal status in boys, complex endocrine interactions are likely involved.

Prenatal exposure to organophosphate pesticides and autism spectrum disorders in 11-year-old children in the French PELAGIE cohort

BACKGROUND

Organophosphate (OP) pesticides act by inhibiting acetylcholinesterase activity at synaptic junctions and have already been linked with deleterious effects on neurodevelopment, including autism spectrum disorders (ASD).

OBJECTIVES

To investigate the association of prenatal exposure to OP pesticides with traits related to ASD in 11-year-old children.

METHODS

The "Childhood Autism Spectrum Test" (CAST) parent questionnaire was used to screen for autistic traits in 792 children from the French PELAGIE cohort. Prenatal maternal urine samples were collected <19 weeks of gestation in which metabolites of organophosphate insecticides were assessed for 185 of them. Negative binomial regression models were performed to explore the association between the CAST score and 8 groups of urine components, adjusted for potential ASD risk factors.

RESULTS

In these urine samples, dialkylphosphates (DAP) were detected most often (>80%), terbufos and its metabolites least often (<10%). No association with ASD was found for DAP, terbufos or its metabolites. Incidence rate ratios (IRRs) increased with maternal urinary diazinon concentrations, from 1.11 (95% CI: 0.87-1.42) to 1.17 (95% CI: 0.94-1.46). Higher CAST scores were statistically significantly associated with the maternal urine samples in which chlorpyrifos or two of its metabolites (chlorpyrifos-oxon and 3,5,6-trichloro-2-pyridinol) were detected. The IRR for exposure to chlorpyrifos or chlorpyrifos-oxon was 1.27 (95%CI: 1.05-1.52) among all children, and 1.39 (95%CI: 1.07-1.82) among boys.

CONCLUSION

These findings suggest an increase in autistic traits among 11-year-old children in association with prenatal maternal exposure to chlorpyrifos and possibly diazinon. These associations were previously suspected in the literature, in particular for chlorpyrifos. Further work establishing the causal mechanisms behind these risk association is needed.

Prenatal and childhood exposure to chlordecone and adiposity of seven-year-old children in the Timoun mother-child cohort study in Guadeloupe (French West Indies)

BACKGROUND

Exposure to persistent environmental organic pollutants may contribute to the development of obesity among children. Chlordecone is a persistent organochlorine insecticide with estrogenic properties that was used in the French West Indies (1973-1993) and is still present in the soil and the water and food consumed by the local population. We studied the association between prenatal and childhood exposure to chlordecone and the adiposity of prepubertal children.

METHODS

Within the Timoun Mother-Child Cohort Study in Guadeloupe (French West Indies), 575 children had a medical examination at seven years of age, including adiposity measurements. A Structural Equation Modeling approach was used to create a global adiposity score from four adiposity indicators: the BMI z-score, percentage of fat mass, sum of the tricipital and subscapular skinfold thickness, and waist-to-height ratio. Chlordecone concentrations were measured in cord blood at birth and in the children's blood at seven years of age. Models were adjusted for prenatal and postnatal covariates. Sensitivity analyses accounted for co-exposure to PCB-153 and pp'-DDE. Mediation analyses, including intermediate birth outcomes, were conducted.

RESULTS

Prenatal chlordecone exposure tended to be associated with increased adiposity at seven years of age, particularly in boys. However, statistical significance was only reached in the third quartile of exposure and neither linear nor non-linear trends could be formally identified. Consideration of preterm birth or birth weight in mediation analyses did not modify the results, as adjustment for PCB-153 and pp'-DDE co-exposures.

CONCLUSION

Globally, we found little evidence of an association between chlordecone exposure during the critical in utero or childhood periods of development and altered body-weight homeostasis in childhood. Nevertheless, some associations we observed at seven years of age, although non-significant, were consistent with those observed at earlier ages and would be worth investing during further follow-ups of children of the Timoun Mother-Child Cohort Study when they reach puberty.

Visuospatial processing and fine motor function among 7-years old Guadeloupe children pre- and postnatally exposed to the organochlorine pesticide chlordecone

BACKGROUND

Chlordecone is an organochlorine that was largely used as an insecticide to control a species of root borers, the Banana weevil (Cosmopolites sordidus), in the French West Indies, Guadeloupe and Martinique. Its molecules have been shown to be very persistent in the environment as pollution in soils leading to contamination of water sources and foodstuff will last for several decades. Our team previously reported associations between prenatal chlordecone exposure and poorer fine motor development at two points in time during infancy.

OBJECTIVE

To document whether effects of prenatal exposure to chlordecone previously reported persists until middle-childhood, and whether deleterious effects are observed in domain of visual processing. Associations with postnatal exposure and sex-specific vulnerabilities were also investigated.

METHODS

We examined 410 children from the TIMOUN mother-child cohort in Guadeloupe at 7 years of age. Concentrations of chlordecone and other environmental contaminants were measured in cord- and children's blood at age 7 years. Fine motor function was assessed using the Bruininks Oseretsky Test of Motor Proficiency Second Edition (BOT-2). The Computerized Adaptive Testing System (CATSYS) was used to evaluated postural hand tremor, while non-verbal visuospatial processing was measured using the Stanford Binet copying (S-B copying) test. We used adjusted multiple linear regressions to test the relationship between children's scores and both continuous and categorical blood chlordecone concentrations, adding child sex as a moderator in continuous models.

RESULTS

Cord chlordecone concentrations are associated with a regular frequency pattern of subtle hand tremors in both hands, and not related to visual processing and fine motor precision. Chlordecone concentrations in blood sample collected at testing time are associated with poorer visual processing when copying geometric figures, but not significantly related to poorer fine movement precision in tasks requiring pencil, scissors and paper. No sex-specific vulnerability was reported in any of the outcomes.

CONCLUSIONS

These results at school aged expand those previously reported in the same cohort during infancy at age 7- and 18 months, and corroborate the negative effects of chlordecone exposure on fine motor function in absence of intoxication. Our results support the need to continue public health efforts aimed at reducing exposure especially among women of child bearing age and young children.

Developmental exposure to chlordecone induces transgenerational effects in somatic prostate tissue which are associated with epigenetic histone trimethylation changes

BACKGROUND

Chlordecone (CD), also known as Kepone, is an organochlorine insecticide that has been used in banana crops in the French West Indies. Due to long-term contamination of soils and water, the population is still exposed to CD. Exposure to CD in adulthood is associated with an increased risk of prostate cancer (PCa).

OBJECTIVES

We examined the transgenerational effects of CD on murine prostate tissue.

METHODS

We exposed pregnant Swiss mice to CD. The prostates from directly exposed (F1) and non-exposed (F3) male progeny were analyzed. We used immunofluorescence, RNA-seq and ChIP-seq techniques for the comprehensive analyses of chromatin states in prostate.

RESULTS

We observed an increased prostatic intraepithelial neoplasia phenotype (PIN) in both F1 and F3 generations. Transcriptomic analysis in CD-derived F1 and F3 prostate using RNA-seq revealed that 970 genes in F1 and 218 in F3 genes were differentially expressed. The differentially expressed genes in both datasets could be clustered accordingly to common biological processes, "cell differentiation", "developmental process", "regulating of signaling", suggesting that in both generations similar processes were perturbed. We detected that in both datasets several Hox genes were upregulated; in F1, the expression was detected mainly in Hoxb and Hoxd, and in F3, in Hoxa family genes. Using a larger number of biological replicates and RT-qPCR we showed that genes implicated in testosterone synthesis (Akr1b3, Cyp11a1, Cyp17a1, Srd5a1) were dramatically upregulated in PIN samples; Cyp19a1, converting testosterone to estradiol was elevated as well. We found a dramatic increase in Esr2 expression both in F1 and F3 prostates containing PIN. The PIN-containing samples have a strong increase in expression of self-renewal-related genes (Nanog, Tbx3, Sox2, Sox3, Rb1). We observed changes in liver, F1 CD-exposed males have an increased expression of genes related to DNA repair, matrix collagen and inflammation related pathways in F1 but not in F3 adult CD-derived liver. The changes in RNA transcription were associated with epigenetic changes. Specifically, we found a global increase in H3K4 trimethylation (H3K4me3) and a decrease in H3K27 trimethylation (H3K27me3) in prostate of F1 mice. ChIP-seq analysis showed that 129 regions in F1 and 240 in F3 acquired altered H3K4me3 occupancy in CD-derived prostate, including highest increase at several promoters of Hoxa family genes in both datasets. The alteration in H3K4me3 in both generations overlap 73 genes including genes involved in proliferation regulation, Tbx2, Stat3, Stat5a, Pou2f3 and homeobox genes Hoxa13, Hoxa9.

CONCLUSIONS

Our data suggest that developmental exposure to CD leads to epigenetic changes in prostate tissue. The PIN containing samples showed evidence of implication in hormonal pathway and self-renewal gene expression that have the capacity to promote neoplasia in CD-exposed mice.

In utero exposure to chlordecone affects histone modifications and activates LINE-1 in cord blood

In utero exposure to chlordecone affects chromatin and leads to activation of retroelements. This study shows the changes induced by chlordecone in human umbilical cord blood and blood-derived cell line.

Environmental factors can induce detrimental consequences into adulthood life. In this study, we examined the epigenetic effects induced by in utero chlordecone (CD) exposure on human male cord blood as well as in blood-derived Ke-37 cell line. Genome-wide analysis of histone H3K4me3 distribution revealed that genes related to chromosome segregation, chromatin organization, and cell cycle have altered occupancy in their promoters. The affected regions were enriched in ESR1, SP family, and IKZF1 binding motifs. We also observed a global reduction in H3K9me3, markedly in repeated sequences of the genome. Decrease in H3K9me3 after CD exposure correlates with decreased methylation in LINE-1 promoters and telomere length extension. These observations on human cord blood were assessed in the Ke-37 human cell line. H3K4me3 and the expression of genes related to immune response, DNA repair, and chromatin organization, which were affected in human cord blood were also altered in CD-exposed Ke-37 cells. Our data suggest that developmental exposure to CD leads to profound changes in histone modification patterns and affects the processes controlled by them in human cord blood.

In Utero Chlordecone Exposure and Thyroid, Metabolic, and Sex-Steroid Hormones at the Age of Seven Years: A Study From the TIMOUN Mother-Child Cohort in Guadeloupe

BACKGROUND

Chlordecone is an endocrine-disrupting chemical with well recognized estrogenic and progestagenic properties. This organochlorine insecticide was extensively used in the French West Indies from 1973 to 1993 to control the banana root borer. Due to its poor degradation in the environment, permanently polluted soil is responsible for the current contamination of the food chain and human beings. We aimed to examine the relationship of in utero exposure to chlordecone and thyroid (thyroid stimulating hormone [TSH], free tri-iodothyronine [FT3], free thyroxine [FT4]), metabolic (insulin growth-factor 1, leptin, adiponectin), and sex-steroid (dehydroepiandrosterone [DHEA], total testosterone [TT], dihydrotestosterone [DHT], estradiol [E2]) hormone levels in children at the age of seven years who participated in TIMOUN, an ongoing birth cohort in Guadeloupe.

METHODS

Chlordecone concentrations were measured in cord-blood at delivery. Thyroid, metabolic, and sex-steroid hormone levels were determined in the blood of children at seven years of age. Associations between in utero chlordecone exposure and hormone levels at seven years of age were assessed by multiple linear or logistic regression, controlling for confounding factors.

RESULTS

Among the study population (210 boys and 228 girls), chlordecone and hormone measurements were available for 124 boys and 161 girls. We found the third quartile of in utero chlordecone exposure relative to the lowest quartile to be associated with elevated TSH levels in girls and elevated DHEA, TT, and DHT levels in both sexes. Complementary non-linear analysis (spline regression) confirmed a significant non-linear trend for TSH in girls and DHEA and DHT in boys.

CONCLUSION

In utero chlordecone exposure was associated with elevated levels of selected thyroid (TSH) and sex-steroid (DHEA, TT, and DHT) hormones at seven years in a non-monotonic dose response (inverted U) relationship. The implications for future health and reproductive function in puberty and adulthood should be determined.

Chlordecone exposure and risk of congenital anomalies: the Timoun Mother-Child Cohort Study in Guadeloupe (French West Indies)

Chlordecone is an organochlorine pesticide that was extensively used to control the banana root borer population in the French West Indies until 1993. Its persistence in soil has led to widespread pollution of the environment, and human beings, including pregnant women, are still exposed to this chemical. High levels of exposure to chlordecone during gestation have been shown to cause congenital anomalies, including undescended testes in rodents. We assessed the associations between chlordecone concentrations in maternal and cord plasma and the risk of congenital anomalies in the Timoun Mother-Child Cohort Study (2004-2007) that included 1068 pregnant women in Guadeloupe. Odds ratios were estimated using unconditional logistic regression analysis, controlling for confounding factors. The median plasma concentrations in maternal and cord plasma were 0.39 μg/L and 0.20 μg/L, respectively. Thirty-six children were diagnosed with malformations according to the European Registration of Congenital Anomalies guidelines and 25 with undescended testes. There was no association between maternal or cord plasma concentration of chlordecone and the risk of overall malformations nor undescended testes. These results suggest that prenatal exposure to the currently observed environmental levels of chlordecone in French West Indies does not increase the risk of birth defects.

Prenatal and childhood exposure to chlordecone and sex-typed toy preference of 7-year-old Guadeloupean children

Chlordecone was used intensively as an insecticide in the French West Indies. Because of its high persistence, the resulting contamination of food and water has led to chronic exposure of the general population as evidenced by its presence in the blood of people of Guadeloupe, in particular in pregnant women and newborns, and in maternal breast milk. Chlordecone is recognized as a reproductive and developmental toxicant, is neurotoxic and carcinogenic in rodents, and is considered as an endocrine-disrupting compound with well-established estrogenic and progestogenic properties both in vitro and in vivo. The question arises of its potential consequences on child neurodevelopment following prenatal and childhood exposure, in particular on behavioral sexual dimorphism in childhood. We followed 116 children from the TIMOUN mother-child cohort study in Guadeloupe, who were examined at age 7. These children were invited to participate in a 7-min structured play session in which they could choose between different toys considered as feminine, masculine, or neutral. The play session was video recorded, and the percentage of the time spent playing with feminine or masculine toys was calculated. We estimated associations between playtime and prenatal exposure to chlordecone (assessed by concentration in cord blood) or childhood exposure (determined from concentrations in child blood obtained at the 7-year follow-up), taking into account confounders and co-exposures to other environmental chemicals. We used a two-group regression model to take into account sex differences in play behavior. Our results do not indicate any modification in sex-typed toy preference among 7-year-old children in relation with either prenatal or childhood exposure to chlordecone.

Prenatal exposure to glycol ethers and visual contrast sensitivity in 6-year-old children in the PELAGIE mother-child cohort

BACKGROUND

Maternal occupational exposure to organic solvents during pregnancy has been associated with decreased visual function in offspring. Glycol ethers (GEs) belong to oxygenated solvents and are widely used both in occupational and domestic contexts.

OBJECTIVES

We aimed to assess associations between prenatal GEs exposure and contrast sensitivity in children.

METHODS

Six GE alkoxy carboxylic acidic metabolites (methoxyacetic acid [MAA], ethoxyacetic acid [EAA], ethoxyethoxyacetic acid [EEAA], butoxyacetic acid [BAA], phenoxyacetic acid [PhAA], and 2-methoxypropionic acid [2-MPA]) were measured in first morning void urine samples collected from 220 early-pregnancy women, in the mother-child PELAGIE cohort (France). Trained investigators administered the Functional Acuity Contrast Test (FACT) to the 6-year-old children, providing scores for 5 spatial frequencies (1.5-18 cycles per degree (cpd)). We standardized biomarker urinary concentrations on urine sampling conditions. Values below the LOD were imputed based on log-normal distribution, generating five datasets for multiple imputation. Linear regression models were adjusted for potential confounders.

RESULTS

GE metabolites were detected in 70-98% of maternal urine samples. Phenoxyacetic acid (PhAA) had the highest median concentration (0.33 mg/L), and 2-methoxypropionic acid (2-MPA) the lowest (0.01 mg/L). Children with higher prenatal PhAA concentrations had poorer FACT scores at various spatial frequencies (fourth vs. first quartile: β_18cpd = -0.90 (95% confidence interval CI = -1.64, -0.16), β_12cpd = -0.92 (95%CI = -1.55, -0.29) and β_1.5cpd = -0.69 (95%CI = -1.19, -0.20)). The 2-MPA log-scale concentration was negatively associated with the FACT score at the 3-cpd stimulus.

DISCUSSION

PhAA is the metabolite of ethylene glycol monophenyl ether present in many cosmetics. 2-MPA is the metabolite of an isomer of propylene glycol methyl ether commonly present in household and industrial cleaning products. Although evidence of biological plausibility is lacking, the study suggests adverse impact of ubiquitous prenatal exposure to some GE on visual functioning among children.

Exposure of pregnant women to organophosphate insecticides and child motor inhibition at the age of 10-12 years evaluated by fMRI

BACKGROUND

Organophosphate pesticides (OP) are widely used for both agricultural and domestic purposes. Epidemiological studies suggest neurotoxicity in children after exposure to organophosphates pesticides (OP) at low levels but possible mechanism is still unclear.

OBJECTIVES

We aimed at investigating the effects of prenatal exposure to OPs on inhibitory control of 10-12 year-old-children assessed by a motor inhibition task during functional magnetic resonance imaging (fMRI).

METHODS

Ninety-five children from the PELAGIE cohort (Brittany-France, from 2002) underwent a fMRI examination during which inhibition was assessed by a Go/No-Go task. Task performance was assessed by average response latency, commission rate and composite performance score (PS). Whole brain activation was estimated by modeling the hemodynamic response related to inhibition demand and successful inhibition. OP exposure was assessed by measuring six dialkylphosphate (DAP) metabolites in the urine of women in early pregnancy (<19 WG). Concentrations were summed to obtain overall levels of diethylphosphate (DE), dimethylphosphate (DM) and total non-specific metabolites (DAP), standardized to homogenize sampling conditions and categorized into levels of exposure: low (reference), moderate or high. Regression models were adjusted for potential cofounders considered by restriction and statistical criteria.

RESULTS

Moderate levels of DAP were associated with a decreased commission rate (β = -6.65%, p = 0.04), indicating improved performance. Increasing levels of DM and DE were associated with decreased brain activity in the left inferior and bilateral superior frontal regions during successful inhibition. We did not observe any differential activation related to inhibitory demands.

DISCUSSION

These results suggest that prenatal OPs may be associated with altered pattern of brain activity in regions related to inhibition among children and need to be confirmed by additional studies.

Impact of Saharan Dust on Severe Small for Gestational Births in the Caribbean

Desert dust transported from the Sahara to the Caribbean generates peak exposures to particulate matter ≤ 10 μm (PM₁₀). We investigated the impact of dust episodes on severe small for gestational-age births in Guadeloupe. The study sample consisted of 911 pregnant women enrolled in the Timoun mother-child cohort. Desert dust exposure was assessed through the mean daily PM₁₀ concentrations averaged over the entire pregnancy. Numerous sociodemographic and medical risk factors were considered as covariates and introduced into multinomial logistic regression models. Odds ratios (ORs) were calculated per SD change (3.08 μg/m³). Among various outcomes, symmetrically growth-retarded births showed the highest OR (3.28, 95% CI: 1.08-10.02). Saharan dust seems to influence weight but not length or head circumference at birth. Given the high OR observed in this study, it is conceivable that Saharan dust plays a role through severe placental insufficiency early in pregnancy.

Prenatal exposure to glycol ethers and response inhibition in 6-year-old children: The PELAGIE cohort study

BACKGROUND

Exposure to glycol ethers (GEs) is suspected of impairing neurodevelopment in children, but the specific impact on their inhibitory capacity, a central deficit of ADHD, has never been studied. We aimed to assess the impact of prenatal exposure to GEs on the response inhibition of children aged six years.

METHODS

In total, 169 mother-child pairs from the French cohort PELAGIE (2002-2006) were studied. Maternal urinary concentrations of six GE metabolites (alkoxycarboxylic acids) were measured during pregnancy. Multiple imputation by quantile regression was used to handle non-detected values and the data were then classified into quartiles. Inhibition of children was evaluated by the Rhythmic Continuous Performance Test 90 (R-CPT90). The inhibition score (percentage of correct responses to non-target stimuli) was corrected for compliance with the instructions (percentage of correct responses to target stimuli). The analysis used a multiple linear regression model, adjusting for confounding factors for each metabolite.

RESULTS

Median concentrations of metabolites ranged from 0.02 mg/L (Ethoxyacetic acid, EAA) to 0.39 mg/L (Phenoxyacetic acid, PhAA). The median corrected inhibition score was 37.9% [first quartile: 29.8 - third quartile: 47.9]. We found a negative and statistically significant association between the inhibition score and prenatal urinary EAA concentration (p-trend = 0.03), with a significant β coefficient for the third quartile (β = -0.064; 95% confidence interval: -0.121, -0.007). There were no statistically significant associations for the other five metabolites.

CONCLUSION

These results are consistent with the hypothesis of possible impact of prenatal environmental exposure on inhibitory capacity among children. Data about the GEs metabolized to EAA (history of exposure sources and toxicokinetics) should be gathered to further interpret these results and guide precautionary measures.

Prenatal exposure to glycol ethers and motor inhibition function evaluated by functional MRI at the age of 10 to 12 years in the PELAGIE mother-child cohort

BACKGROUND

Pregnant women are ubiquitously exposed to organic solvents, such as glycol ethers. Several studies suggest potential developmental neurotoxicity following exposure to glycol ethers with a lack of clarity of possible brain mechanisms.

OBJECTIVES

We investigated the association between urinary levels of glycol ethers of women during early pregnancy and motor inhibition function of their 10- to 12-year-old children by behavioral assessment and brain imaging.

METHODS

Exposure to glycol ethers was assessed by measuring six metabolites in urine (<19 weeks of gestation) of 73 pregnant women of the PELAGIE mother-child cohort (France). Maternal urinary levels were classified as low, medium, or high. Children underwent functional magnetic resonance imaging (fMRI) examinations during which motor inhibition function was assessed with a Go/No-Go task. Analyses were performed using linear regression for task performance and generalized linear mixed-effect models for brain activation, FWER-corrected for multiple testing at the spatial cluster level. Confounders were considered by restriction and a priori adjustment.

RESULTS

Higher maternal butoxyacetic acid (BAA) urinary concentrations were associated with poorer child performance (β = -1.1; 95% CI: -1.9, -0.2 for high vs low). There was also a trend for ethoxyacetic acid (EAA) towards poorer performance (β = -0.3; 95% CI: -0.7, 0.01). Considering inhibition demand, there were increased activity in occipital regions in association with moderate EAA (left cuneus) and moderate methoxyacetic acid (MAA) (right precuneus). When children succeeded to inhibit, high ethoxyethoxyacetic acid (EEAA) and moderate phenoxyacetic acid (PhAA) levels were associated with differential activity in frontal cortex, involved in inhibition network.

DISCUSSION

Prenatal urinary levels of two glycol ether metabolites were associated with poorer Go/No-Go task performance. Differential activations were observed in the brain motor inhibition network in relation with successful inhibition, but not with cognitive demand. Nevertheless, there is no consistence between performance indicators and cerebral activity results. Other studies are highly necessary given the ubiquity of glycol ether exposure.

Home environment: respiratory and allergic phenotypes from birth to age six in the PELAGIE cohort

Childhood asthma and allergies are particularly prevalent diseases. Our objective is to identify respiratory and allergic phenotypes from birth to 6 years of age, and to explore their environmental determinants, especially those related to the home environment. Data on respiratory and allergic health outcomes and domestic environmental exposure were collected for 935 mother–infant pairs from a longitudinal mother–child cohort based on mothers, included before 19 weeks of gestation in Brittany between 2002 and 2006. Information was obtained by self-administered questionnaires completed by parents at inclusion, delivery, and when the child was 2 and 6 years old. Kml3D clustering was used to describe profiles of children who shared similar trajectories of symptoms as phenotypes. Association with environmental determinants was estimated by polytomous logistic regression. Five phenotypes were identified: a reference group characterized by low symptom levels (31.1%), a transient cough phenotype (36.5%), an eczema/cough phenotype (12.3%), a wheeze/cough phenotype (11.8%), and finally a mixed phenotype (8.0%). The wheeze/cough profile was associated with postnatal exposure to glues used in renovation activities (aOR 2.3 [1.2–4.7]), and the mixed phenotype with postnatal exposure to paint (aOR 2.1 [1–4.5]). The phenotypes observed showed some consistencies with those seen in previous studies. Some exposures associated with respiratory/allergic phenotypes observed in this study are avoidable. If confirmed by further research including interventional trials, home-based environmental counseling could be a possible prevention target for primary care professionals.

Landfills and preterm birth in the Guadeloupe archipelago (French West Indies): a spatial cluster analysis

Background

A high rate of preterm birth is observed in the Guadeloupe archipelago (French West Indies), raising the hypothesis of harmful environmental exposures, including landfilling. Our aim was to evaluate whether preterm births cluster around the three main open landfills located in this area.

Methods

The study population consisted of 911 women enrolled in the Timoun mother-child cohort (2004–2007). Home addresses during pregnancy and locations of landfills were geocoded. To test for the presence of preterm birth clusters around each dumpsite, we used a focused cluster test specifically designed to detect spatial clustering around point sources.

Results

A total of 144 (15.8%) preterm births were observed among 911 births. Using the term births (n = 767) as controls, a significant cluster was identified within 2 km around the Saint-François landfill with a relative risk (RR) of 4.82 (p = 0.04). No clusters were found around the other two landfills (RR = 2.01, p = 0.26 and RR = 1.06, p = 0.64, for La Gabarre and Baillif, respectively).

Conclusion

The paucity of data available on open landfill sites regarding waste quantities, composition, and changes over time precludes any site-specific interpretation because of the variable degree of possible emissions. This result has to be confirmed in other tropical island environments where waste management has become a major concern with the potential to negatively impact the environment and public health.

Blood Pressure, Heart Rate Variability, and Adiposity in Caribbean Pre-pubertal Children

Childhood obesity prevalence has increased over the last 30 years. The Heart Rate Variability (HRV) studies performed in adults suggest a possible relation between abnormal autonomic regulation and hypertension in the situation of overweight or obesity. Objective: The aims of this study were to explore the early relationships between adiposity and blood pressure and HRV in pre-pubertal children. Methods: Data were collected during the medical examination of the follow-up at 7 years of the TIMOUN mother-child cohort in Guadeloupe. Body Mass Index z-score (zBMI), sum of tricipital and subscapular skinfold thickness, percentage of fat mass, and Waist-to-Height Ratio were measured. A global corpulence score was computed using a Principal Component Analysis (PCA). Systolic Blood Pressure (SBP) and HRV parameters (cardiac holter monitoring) were collected under 2 conditions (calm and tachycardial period). Relations between HRV, SBP, each adiposity indicator and the corpulence score were studied with restricted cubic splines models, and linear regression models. The age at adiposity rebound (AR) was estimated from the individual growth curves. Results: 575 children were included in the SBP study (mean age: 7.7 years, from 85 to 99 months). SBP was linearly correlated with the corpulence score and the zBMI. An increase of 1 in the zBMI was associated with an increase of 2.3 (±0.28) mmHg in SBP. The effect-size of zBMI on SBP was higher in children with early age at AR. Compared to children with normal BMI, children with a zBMI <™2SD had their RMSSD, SDNN, LF and HF indicators in tachycardial conditions significantly reduced by -30, -21, -37, and -48%, respectively. In boys with a zBMI >2SD, we observed a global increase in all HRV parameters (under tachycardial conditions), particularly the LF [β = 0.43 (±0.18)]. Conclusion: In pre-pubertal period a positive correlation between adiposity excess and SBP was observed with significant changes of HRV in boys, arguing for an early abnormal autonomic regulation and for early preventive intervention in the infancy period, particularly in case of overweight or obesity. Thinness was associated with a reduction in almost all the HRV parameters studied, when compared to normal corpulence, suggesting a decrease in autonomic influence.

Correction to: Occupational exposure to organic solvents during pregnancy and childhood behavior: findings from the PELAGIE birth cohort (France, 2002-2013)

Following publication of the original article [1], the author asked to replace Table 2 with the correct version.

Occupational exposure to organic solvents during pregnancy and childhood behavior: findings from the PELAGIE birth cohort (France, 2002-2013)

BACKGROUND

Numerous industries use organic solvents, and many workers from various occupational sectors are exposed to these known neurotoxicants, including pregnant women. Our objective is to explore whether occupational exposure of pregnant women to solvents may impair the neurodevelopment of their babies and consequently affect their behavior in childhood.

METHODS

Within the French birth cohort PELAGIE, parents assessed their children's internalizing and externalizing behaviors using items from the Child Behavior Checklist and the Preschool Social Behavior Questionnaire at age 2, and the Strength and Difficulties Questionnaire at age 6. The occupational exposure to solvents of the pregnant women was self-reported prospectively at the beginning of their pregnancy (N = 715). We applied structural equation modeling to capture the longitudinal association of prenatal exposure to solvents with children's behavioral traits at 2 and 6 years.

RESULTS

Increased externalizing behavior score at age 2 was associated with prenatal exposure to solvents (standardized score: 0.34 (95% CI = 0.11, 0.57) for occasional exposure and 0.26 (0.05, 0.48) for regular exposure). This association was attenuated at age 6 (0.22 (- 0.02, 0.47) for occasional exposure and 0.07 (- 0.14, 0.28) for regular exposure). No association was observed for internalizing behavior.

CONCLUSIONS

Pregnant women's occupational exposure to solvents may affect their children's behavior in early childhood. This effect may be attenuated with aging or diluted by the effects of other postnatal predictors.

Prenatal exposure to glycol ethers and sex steroid hormones at birth

BACKGROUND

Glycol ethers (GEs) are oxygenated solvents widely found in occupational and consumer water-based products. Some of them are well-known reproductive and developmental toxicants.

OBJECTIVES

To study the variations in circulating sex steroid hormones, measured in cord blood, according to biomarkers of prenatal GE exposure.

METHODS

The study population comes from the PELAGIE mother-child cohort, which enrolled pregnant women from Brittany (France, 2002-2006). Maternal urine samples were collected from a random subcohort (n = 338) before 19 weeks' gestation, from which we measured 8 alkoxycarboxylic metabolites of GEs. We subsequently measured 13 sex steroid hormones and sex hormone-binding globulin (SHBG) in cord blood samples. Linear regressions adjusted for potential confounders were used, and nonlinear dose-response associations were investigated.

RESULTS

The detection rates of GE metabolites ranged from 4% to 98%; only the 5 most detected (>20%) metabolites were investigated further. Phenoxyacetic acid (detection rate > 95%) was associated with lower levels of SHBG and various steroids (17-alpha-hydroxy-Pregnenolone, delta-5-androstenediol, and dehydroepiandrosterone) among boys and higher SHBG and 16-alpha-hydroxy-dehydroepiandrosterone levels among girls. The two other highly detected metabolites, methoxyetoxyacetic acid and butoxyacetic acid, were associated with variations in estradiol. Butoxyacetic acid was associated with higher delta-5-androstenediol levels while detectable levels of methoxyacetic acid were associated with lower levels of this hormone.

CONCLUSION

Our study suggests that prenatal exposure to GE may affect endocrine response patterns, estimated by determining blood levels of sex steroid hormones in newborns. These results raise questions about the potential role of these changes in the pathways between prenatal GE exposure and previously reported adverse developmental outcomes, including impaired neurocognitive performance.

Prenatal exposure to glycol ethers and cryptorchidism and hypospadias: a nested case–control study

Objectives

Glycol ethers (GE) are oxygenated solvents frequently found in occupational and consumer products. Some of them are well-known testicular and developmental animal toxicants. This study aims to evaluate the risk of male genital anomalies in association with prenatal exposure to GE using urinary biomarkers of exposure.

Methods

We conducted a case–control study nested in two joint mother–child cohorts (5303 pregnant women). Cases of cryptorchidism and hypospadias were identified at birth and confirmed during a 2-year follow-up period (n=14 cryptorchidism and n=15 hypospadias). Each case was matched to three randomly selected controls within the cohorts for region of inclusion and gestational age at urine sampling. Concentrations of five GE acidic metabolites were measured in spot maternal urine samples collected during pregnancy. ORs were estimated with multivariate conditional logistic regressions including a Firth’s penalisation.

Results

Detection rates of urinary GE metabolites ranged from 8% to 93% and only two were sufficiently detected (>33%) in each cohort to be studied: methoxyacetic acid (MAA) and phenoxyacetic acid (PhAA). A significantly higher risk of hypospadias was associated with the highest tertile of exposure to MAA: OR (95% CI) 4.5(1.4 to 23.4). No association were observed with urinary concentration of PhAA, nor with the risk of cryptorchidism.

Conclusions

In view of the toxicological plausibility of our results, this study, despite its small sample size, raises concern about the potential developmental toxicity of MAA on the male genital system and calls for thorough identification of current sources of exposure to MAA.

Determinants of children's exposure to pyrethroid insecticides in western France

Pyrethroids are insecticides frequently used in agriculture and in the home; exposure occurs through dietary and non-dietary pathways, including indoor and outdoor environmental contamination. Our objective was to study the potential determinants of pyrethroid metabolite concentrations measured in children's urine samples and in the dust of their homes. Specifically, we measured urinary metabolites from morning spot samples of 245 six-year-old children living in Brittany (France) in 2009-2012 and from dust vacuumed from the floor of their homes. Mothers reported home insecticide use, dietary habits, sociodemographic data; residential and school proximity to agricultural crops was assessed with spatialized data. The metabolites cis-DBCA, trans-DCCA, cis-DCCA, 3-PBA, and F-PBA were detected in 84, 95, 64, 63, and 16% of the urine samples, respectively. Permethrin, cypermethrin, cyfluthrin, deltamethrin, and tetramethrin pyrethroids were detected in 100, 56, 9, 15, and 26% of the dust samples, respectively. Multiple regression analysis suggested diet plays a role in children's exposure, in particular, the food groups "pasta, rice or semolina" (for cis-DCCA and F-PBA), fruit (3-PBA), "breakfast cereals and whole grain bread" (cis-DBCA), and the global proportion of organic food in diet (for cis-DBCA, trans-DCCA). Children with a parent occupationally exposed to pesticides were about 3-times more likely to have higher urinary concentrations of 3-PBA (OR=2.8, 95% CI [1.2; 6.5]). Dust content was correlated mainly with household insecticide use: higher mean concentrations of permethrin (β=0.8 [0.3; 1.3], in μg/g) and an increased risk of a detectable level of cyfluthrin (OR=4.7 [1.7; 12.9]) were observed in home dust, for indoor use of at least twice a year. Outdoor insecticide use at least once a year was associated with detection in dust of cypermethrin (OR=3.0 [1.3; 6.7]) and tetramethrin (OR=3.7 [1.6; 8.3]). Three positive and one negative correlations (out of 11) between urinary metabolite concentrations and home dust contents of their possible corresponding parent compounds were observed. The strength of this study lies in its concurrent use of biomarkers, environmental measurements, and potential sources of exposure. Its limitations include the use of a single urine sample and imprecise data about pyrethroid use in local agriculture.

Prenatal Exposure to Glycol Ethers and Neurocognitive Abilities in 6-Year-Old Children: The PELAGIE Cohort Study

BACKGROUND

Glycol ethers (GE) are widely used organic solvents. Despite the potential neurotoxicity of several families of organic solvents, little is known about the impact of GE on the neurodevelopment of infants and children.

OBJECTIVES

We investigated the relation between urinary concentrations of GE metabolites in pregnant women and neurocognitive abilities in their 6-year-old children in the PELAGIE mother-child cohort.

METHODS

Five GE metabolites were measured in first morning void urine samples of 204 French pregnant women in early pregnancy (< 19 weeks of gestation). Psychologists assessed the neurocognitive abilities of their 6-year-old children with the Wechsler Intelligence Scale for Children IV (WISC) and the Developmental Neuropsychological Assessment (NEPSY). We analyzed the results with linear (WISC) and Poisson regression models (NEPSY), adjusted for potential confounders, including child's stimulation at home.

RESULTS

GE metabolites were detected in 90-100% of maternal urine samples. The WISC Verbal Comprehension score was significantly lower for children with the highest tertile of urinary phenoxyacetic acid (PhAA) [β (third vs. first tertile) = -6.53; 95% CI: -11.44, -1.62]. Similarly, the NEPSY Design Copying subtest score was lower in those with the highest tertile of urinary ethoxyacetic acid (EAA) [β (third vs. first tertile) = -0.11; 95% CI: -0.21, 0.00]. The other GE metabolites we studied were not significantly associated with WISC or NEPSY scores.

CONCLUSIONS

Prenatal urine concentrations of two GE metabolites were associated with lower WISC Verbal Comprehension Index scores and NEPSY Design Copying subscale scores, respectively, at age 6 years. PhAA is the primary metabolite of 2-phenoxyethanol (EGPhE), which is commonly found in cosmetics, and precursors of EAA are frequently used in cleaning agents. Additional research is needed to confirm our findings and further explore potential effects of prenatal GE exposures on neurocognitive performance in children.

Behavioural disorders in 6-year-old children and pyrethroid insecticide exposure: the PELAGIE mother-child cohort

OBJECTIVE

The potential impact of environmental exposure to pyrethroid insecticides on child neurodevelopment has only just started to receive attention despite their widespread use. We investigated the associations between prenatal and childhood exposure to pyrethroid insecticides and behavioural skills in 6-year-olds.

METHODS

The PELAGIE cohort enrolled 3421 pregnant women from Brittany, France between 2002 and 2006. 428 mothers were randomly selected for the study when their children turned 6, and 287 (67%) agreed to participate. Children's behaviour was assessed using the Strengths and Difficulties Questionnaire (SDQ). Three subscales (prosocial behaviour, internalising disorders and externalising disorders) were considered. Five pyrethroid metabolites were measured in maternal and child urine samples collected between 6 and 19 gestational weeks and at 6 years of age, respectively. Logistic regression and reverse-scale Cox regression models were used to estimate the associations between SDQ scores and urinary pyrethroid metabolite concentrations, adjusting for organophosphate metabolite concentrations and potential confounders.

RESULTS

Increased prenatal cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (DCCA) concentrations were associated with internalising difficulties (Cox p value=0.05). For childhood 3-phenoxybenzoic acid (PBA) concentrations, a positive association was observed with externalising difficulties (Cox p value=0.04) and high ORs were found for abnormal or borderline social behaviour (OR 2.93, 95% CI 1.27 to 6.78, and OR 1.91, 95% CI 0.80 to 4.57, for the intermediate and highest metabolite categories, respectively). High childhood trans-DCCA concentrations were associated with reduced externalising disorders (Cox p value=0.03).

CONCLUSIONS

The present study suggests that exposure to certain pyrethroids, at environmental levels, may negatively affect neurobehavioral development by 6 years of age.

Prenatal exposure to chlordecone, gestational weight gain, and birth weight in a Guadeloupean birth cohort

BACKGROUND

Chlordecone is a persistent organochlorine insecticide with well-defined estrogenic properties. It was intensively used in the French West Indies until 1993 to control the banana root borer. Because of the long-term contamination of soils and water, the population is currently exposed to chlordecone through food consumption. Chlordecone has been found in the blood of pregnant women and in cord blood. It has been shown to be an endocrine-disrupting chemical and exposure during pregnancy may affect fetal growth.

OBJECTIVES

The objective of our study was to examine the association between prenatal exposure to chlordecone and fetal growth based on the TIMOUN birth cohort conducted in Guadeloupe, with a focus on the potential modification of this relationship by maternal body mass index (BMI) and gestational weight gain (GWG).

METHODS

Chlordecone was determined in cord plasma at birth in 593 babies. Birth weight was the indicator of fetal growth. Maternal pre-pregnancy BMI and GWG were determined. Adherence to GWG recommendations of the US Institute of Medicine based on maternal pre-pregnancy BMI was assessed. Birth weight was analyzed relative to cord blood chlordecone levels using linear and non-linear regression models.

RESULTS

Overall chlordecone in cord blood was not associated with birth weight, but we found an interaction between chlordecone exposure with GWG and adherence to GWG recommendations. After stratification by GWG, we found a significant U-shaped association between birth weight and chlordecone exposure, within the upper quartiles of GWG or excessive GWG.

CONCLUSION

Chlordecone exposure may affect fetal growth, particularly when excessive GWG is present.

Organophosphate Insecticide Metabolites in Prenatal and Childhood Urine Samples and Intelligence Scores at 6 Years of Age: Results from the Mother-Child PELAGIE Cohort (France)

BACKGROUND

Several studies suggest that exposure to organophosphate insecticides (OP) during pregnancy impairs neurodevelopment in children.

OBJECTIVES

We evaluated associations between biomarkers of prenatal and postnatal OP exposure and cognitive function of 6-year-olds in a French longitudinal birth cohort.

METHODS

In 2002-2006, the PELAGIE mother-child cohort enrolled pregnant women from Brittany. For a random subcohort, we measured nonspecific dialkylphosphate metabolites (DAP) of OP in one maternal urine sample, collected before 19 weeks' gestation, and in one urine sample collected from their 6-year-old children. Six subtests of the Wechsler Intelligence Scale for Children, 4th edition (WISC-IV) were administered when the children were 6 years of age to evaluate cognitive function (n = 231). Linear regression models controlling for factors including maternal intelligence and the Home Observation for Measurement of the Environment score were used.

RESULTS

WISC-IV scores were not significantly associated with prenatal or childhood total DAP metabolites. WISC verbal comprehension score was significantly higher in association with the highest maternal urinary concentrations of diethylphosphate (DE) metabolites (5.5; 95% CI: 0.8, 10.3 for > 13.2 nmol/L vs. < LOQ), whereas WISC working memory score was significantly lower in association with the highest urinary concentrations of DE metabolites at age 6 years (-3.6; 95% CI: -7.8, -0.6 for > 11.1 nmol/L vs. < LOD).

CONCLUSION

We found no evidence that prenatal OP exposure adversely affected cognitive function in 6-year-olds, perhaps because of the population's socioeconomic status, which was higher than in previous studies, though other causal and noncausal explanations are also possible. The negative association between WISC score and concurrent DE urinary concentrations requires replication by longitudinal studies investigating childhood OP exposure.

CITATION

Cartier C, Warembourg C, Le Maner-Idrissi G, Lacroix A, Rouget F, Monfort C, Limon G, Durand G, Saint-Amour D, Cordier S, Chevrier C. 2016. Organophosphate insecticide metabolites in prenatal and childhood urine samples and intelligence scores at 6 years of age: results from the mother-child PELAGIE cohort (France). Environ Health Perspect 124:674-680; http://dx.doi.org/10.1289/ehp.1409472.

Prenatal exposure to persistent organic pollutants and organophosphate pesticides, and markers of glucose metabolism at birth

BACKGROUND

Experimental evidence suggests that developmental exposure to persistent organic pollutants (POP) and to some non persistent pesticides may disrupt metabolic regulation of glucose metabolism and insulin secretion, and thereby contribute to the current epidemic of obesity and metabolic disorders. Quasi-experimental situations of undernutrition in utero have provided some information. However, the evidence in humans concerning the role of the prenatal environment in these disorders is contradictory, and little is known about long-term outcomes, such as type 2 diabetes, of prenatal exposure.

OBJECTIVES

Our aim was to evaluate the effects of prenatal exposure to POP and organophosphate pesticides on fetal markers of glucose metabolism in a sample of newborns from the Pelagie mother-child cohort in Brittany (France).

METHODS

Dialkylphosphate (DAP) metabolites of organophosphate pesticides were measured in maternal urine collected at the beginning of pregnancy. Cord blood was assayed for polychlorinated biphenyl congener 153 (PCB153), p,p'-dichlorodiphenyl dichloroethene (DDE) and other POP. Insulin and adiponectin were determined in cord blood serum (n=268).

RESULTS

A decrease in adiponectin and insulin levels was observed with increasing levels of DDE, but only in girls and not boys. Adiponectin levels were not related to the concentrations of other POP or DAP metabolites. Decreasing insulin levels were observed with increasing PCB153 concentrations. Insulin levels increased with DAP urinary levels. Additional adjustment for BMI z-score at birth modified some of these relations.

CONCLUSIONS

Our observations bring support for a potential role of organophosphate pesticides and POP in alterations to glucose metabolism observable at birth.

Childhood exposure to polybrominated diphenyl ethers and neurodevelopment at six years of age

Mixtures of polybrominated diphenyl ethers (PBDEs) are present in indoor environments. Studies of the developmental effects of exposure to these chemicals in large prospective mother-child cohorts are required, with data on prenatal exposure and long-term follow-up of the children. We aimed to investigate the relationship between prenatal and childhood exposure to PBDEs and neurodevelopment at the age of six years. We determined the levels of PBDEs and other neurotoxicants in cord blood and dust collected from the homes of children for 246 families included in the PELAGIE mother-child cohort in France. We assessed two cognitive domains of the six-year-old children using the Wechsler Intelligence Scale for Children-IV. Verbal comprehension scores were lower in children from homes with higher concentrations of BDE99 (βDetects<median_vs_NonDetects=-1.6; 95% CI: -6.1, 2.9; βDetects≥median_vs_NonDetects=-5.4; -9.9, -1.0; p trend=0.02) and of BDE209 (β2nd_vs_1st_tertile=-1.8; 95% CI: -6.1, 2.5; β3rd_vs_1st_tertile=-3.2; -7.5, 1.2; p trend=0.15) in dust, particularly for boys (p trend=0.02 and 0.04, respectively). Working memory scores seemed to be lower in children with higher BDE99 concentrations in dust (p trend=0.10). No association was observed with cord blood levels of BDE209. Our findings are in agreement with those of four previous studies suggesting adverse cognitive outcomes among children associated with early-life exposure to penta-BDE mixtures, and provide new evidence for the potential neurotoxicity of BDE209. Several countries are in the process of banning the use of PBDE mixtures as flame-retardants. However, these compounds are likely to remain present in the environment for a long time to come.

Sex-specific differences in fetal growth in newborns exposed prenatally to traffic-related air pollution in the PELAGIE mother-child cohort (Brittany, France)

BACKGROUND

Numerous studies have linked prenatal traffic-related air pollution exposure to fetal growth. Recently, several studies have suggested exploring this association independently among boys and girls because of potential sex-specific biological vulnerability to air pollution. Residence-based factors can also influence fetal growth by enhancing susceptibility to the toxic effects of air pollution and must also be considered in these relations.

OBJECTIVE

We examined sex-specific associations between prenatal air pollution exposure and fetal growth and explored whether they differed by the urban-rural status of maternal residence.

METHODS

This study relied on the PELAGIE mother-child cohort (2521 women, Brittany, France, 2002-2006). Fetal growth was assessed through birth weight, head circumference and small weight (SGA) and small head circumference (SHC) for gestational age. Nitrogen dioxide (NO2) concentrations at mothers' homes were estimated by using a land use regression model taking into account temporal variation during pregnancy. Associations between estimated NO2 concentrations and fetal growth were assessed with linear regression or logistic regression models, depending on the outcome investigated.

RESULTS

An interquartile range (8.8 µg m(-3)) increase in NO2 exposure estimates was associated with a 27.4 g (95% CI 0.8 to 55.6) increase in birth weight and a 0.09 cm (95% CI 0.00-0.17) significant increase in head circumference, among newborn boys only. Their risks of SGA and SHC were reduced (OR 0.70, 95% CI 0.53-0.92, OR 0.76, 95% CI 0.56-1.03, respectively, for an increase of 8.8 µg m(-3)). No statistically significant trends were observed among girls. Urban-rural status modified the effect of air pollution only for SHC and again only for newborn boys.

CONCLUSION

Findings from this study confirm the need to consider sex-specific associations between air pollution and fetal growth and to investigate possible mechanisms by which traffic-related air pollution may increase anthropometric parameters at birth.

Perinatal exposure to chlordecone and infant growth

BACKGROUND

The intensive use of chlordecone (an organochlorine insecticide) in the French West Indies until 1993 resulted in a long-term soil and water contamination. Chlordecone has known hormonal properties and exposure through contaminated food during critical periods of development (gestation and early infancy) may affect growth.

OBJECTIVES

We aimed to assess the impact of prenatal and postnatal exposure to chlordecone on the growth of children from the TIMOUN mother-child cohort.

METHODS

Chlordecone was determined in cord plasma at birth (N=222) and in breast milk samples (at 3 months). Dietary chlordecone intake was estimated at 7 and 18 months, with food-frequency questionnaires and food-specific contamination data. Anthropometric measurements were taken at the 3-, 7- and 18-month visits and measurements reported in the infants' health records were noted. Structured Jenss-Bayley growth models were fitted to individual height and weight growth trajectories. The impact of exposure on growth curve parameters was estimated directly with adjusted mixed non-linear models. Weight, height and body mass index (BMI), and instantaneous height and weight growth velocities at specific ages were also analyzed relative to exposure.

RESULTS

Chlordecone in cord blood was associated with a higher BMI in boys at 3 months, due to greater weight and lower height, and in girls at 8 and 18 months, mostly due to lower height. Postnatal exposure was associated with lower height, weight and BMI at 3, 8 and 18 months, particularly in girls.

CONCLUSION

Chlordecone exposure may affect growth trajectories in children aged 0 to 18 months.

Association between prenatal exposure to traffic-related air pollution and preterm birth in the PELAGIE mother-child cohort, Brittany, France. Does the urban-rural context matter?

INTRODUCTION

Evidence has accumulated that exposure to ambient air pollution during pregnancy may influence preterm birth (PTB) in urban settings. Conversely, this relation has barely been investigated in rural areas where individual characteristics (demographic, socioeconomic, and psychosocial factors) and environmental co-exposures may differ.

OBJECTIVE

We examined the association between prenatal exposure to traffic-related air pollution and PTB among pregnant women from the PELAGIE mother-child cohort (Brittany, France, 2002-2006) living in urban (n=1550) and rural (n=959) settings.

METHODS

Women's residences were classified as either urban or rural according to the French census bureau rural-urban definitions. Nitrogen dioxide (NO2) concentrations at home addresses were estimated from adjusted land-use regression models as a marker of traffic-related pollution. Associations between NO2 concentrations and PTB were assessed with logistic regression models.

RESULTS

Prevalence of PTB was similar among women living in urban (3.2%) and in rural (3.5%) settings. More positive socioeconomic characteristics and health behaviors but more single-parent families were observed among urban women. NO2 exposure averaged 20.8±6.6 µg m(-3) for women residing in urban areas and 18.8±5.6 µg m(-3) for their rural counterparts. A statistically significant increased risk of PTB was observed among women exposed to NO2 concentrations ≥16.4 µg m(-3) and residing in urban areas but not among their rural counterparts.

DISCUSSION

The results of this study, conducted in a region with interspersed urban-rural areas, are in line with previous findings suggesting an increased risk of PTB associated with higher NO2 concentrations for women living in urban areas. The absence of association among their rural counterparts for whom exposure levels were similar suggests that environmental mixtures and psychosocial inequalities might play a role in this heterogeneity.

Prenatal pesticide exposure and otitis media during early childhood in the PELAGIE mother-child cohort

OBJECTIVE

Contemporary pesticides, such as triazines or organophosphates, possess immunotoxic properties. We aimed to determine whether prenatal environmental exposure to these current-use pesticides was associated with otitis media (OM) during the first 2 years of life among children from the PELAGIE mother-child cohort.

METHODS

The PELAGIE cohort enrolled 3421 women at the beginning of pregnancy in Brittany (France). At the 2-year follow-up, 1505 families completed a self-administered questionnaire, including the domestic use of pesticides and consumption of organic diet during pregnancy and occurrences of OM in the child. Two health outcomes were considered: at least one OM and recurrent OM (at least three). Multivariate logistic regression models that adjusted for known risk factors of OM were performed. Metabolites of triazine herbicides and organophosphate insecticides measured in urine collected before the 19th week of gestation (248 mothers) were considered in a subgroup analysis. Multiple imputation was used to handle missing values for the covariates.

RESULTS

Children whose mothers reported an organic diet during pregnancy had a reduced risk of OM (at least one episode, p trend=0.01). No association was found between any outcome and residential proximity to crops. The presence in maternal urine of dealkylated triazine metabolites (OR=2.12 (1.01 to 4.47)) was positively associated with recurrent OM.

CONCLUSIONS

To the best of our knowledge, this is the first work to suggest a positive association between prenatal exposure to current-use pesticides and the occurrence of parent-reported OM in young children.

Pyrethroid insecticide exposure and cognitive developmental disabilities in children: The PELAGIE mother-child cohort

Pyrethroid insecticides are widely used in agriculture and in homes. Despite the neurotoxicity of these insecticides at high doses, few studies have examined whether lower-level exposures could adversely affect children's neurodevelopment. The PELAGIE cohort included 3421 pregnant women from Brittany, France between 2002 and 2006. When their children reached their sixth birthday, 428 mothers from the cohort were randomly selected, successfully contacted and found eligible. A total of 287 (67%) mothers agreed to participate with their children in the neuropsychological follow-up. Two cognitive domains were assessed by the Wechsler Intelligence Scale for Children: verbal comprehension and working memory. Five pyrethroid and two organophosphate insecticide metabolites were measured in maternal and child first-void urine samples collected between 6 and 19 gestational weeks and at 6years of age, respectively. Linear regression models were used to estimate associations between cognitive scores and urinary pyrethroid metabolite concentrations, adjusting for organophosphate metabolite concentrations and potential confounders. Maternal prenatal pyrethroid metabolite concentrations were not consistently associated with any children's cognitive scores. By contrast, childhood 3-PBA and cis-DBCA concentrations were both negatively associated with verbal comprehension scores (P-trend=0.04 and P-trend<0.01, respectively) and with working memory scores (P-trend=0.05 and P-trend<0.01, respectively). No associations were observed for the three other childhood pyrethroid metabolite concentrations (4-F-3-PBA, cis-DCCA, and trans-DCCA). Low-level childhood exposures to deltamethrin (as cis-DBCA is its principal and selective metabolite), in particular, and to pyrethroid insecticides, in general (as reflected in levels of the 3-PBA metabolite) may negatively affect neurocognitive development by 6years of age. Whatever their etiology, these cognitive deficits may be of importance educationally, because cognitive impairments in children interfere with learning and social development. Potential causes that can be prevented are of paramount public health importance.

Socioeconomic Disparities in Adverse Birth Outcomes in Urban and Rural Contexts: a French Mother-Child Cohort

BACKGROUND

Although adverse birth outcomes have been associated with neighbourhood deprivation in urban areas, few studies have addressed this issue in rural zones. This study examines whether associations between neighbourhood deprivation and adverse birth outcomes differ in urban and rural contexts, while taking individual characteristics and spatial accessibility of prenatal care (SAPC) into account.

METHODS

Pregnant women from a French mother-child cohort were recruited from 2002 to 2006 in Brittany. Their residential addresses were geocoded into their census blocks (the finest geographical resolution available). Deprivation was assessed at the same neighbourhood level. Models to assess the associations of deprivation, stratified by urban/rural status, with preterm delivery (PTD), with small for gestational age birth weight (SGA) and with small for gestational age head circumference at birth (SHC), estimated odds ratios (ORs), adjusted for maternal socioeconomic characteristics and SAPC.

RESULTS

This study considered 2929 liveborn singleton pregnancies from 780 census blocks. Neighbourhood deprivation was associated with increased risks of SGA and SHC (P trend < 0.01 and 0.03 respectively), only among mothers residing in rural areas. Neighbourhood deprivation had statistically significantly heterogeneous effects on SGA and SHC according to the urban/rural status of maternal residence.

CONCLUSION

These findings suggest that neighbourhood deprivation affects fetal growth differentially in urban and rural areas and that SAPC does not seem to be responsible for this difference. Comparison of these findings with the literature requires caution in the conceptualisation of urban and rural settings.