Children's contrast sensitivity function in relation to organophosphate insecticide prenatal exposure in the mother-child PELAGIE cohort.

Human exposure to organophosphate pesticides (OP) is widespread. Several studies suggest that OP prenatal exposure alters the development of cognitive and behavioural functions in children, but the effects of OP prenatal exposure on child sensory functions are largely unknown. The aim of the study was to evaluate the association between OP prenatal exposure and visual processing in school-aged children from the mother-child PELAGIE cohort (France). OP biomarkers of exposure were measured in maternal urine samples at the beginning of pregnancy. The Functional Acuity Contrast Test (FACT) was used to assess visual contrast sensitivity in 180 children at 6 years of age. Linear regression models were performed on all children, and separately for boys and girls, taking into account various potential confounders, including maternal education and breastfeeding. No associations were observed in the whole sample, while maternal OP urinary metabolite levels were associated with a decrease of FACT scores in boys. These findings indicate that OP prenatal exposure might impair visual processing later in life in boys only.

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 and early-life polychlorinated biphenyl (PCB) levels and behavior in Inuit preschoolers.

BACKGROUND: Whereas it is well established that prenatal exposure to polychlorinated biphenyls (PCBs) can disrupt children's behavior, early postnatal exposure has received relatively little attention in environmental epidemiology. OBJECTIVES: To evaluate prenatal and postnatal exposures to PCB-153, a proxy of total PCB exposure, and their relation to inattention and activity in 5-year-old Inuits from the Cord Blood Monitoring Program. METHODS: Prenatal exposure to PCBs was informed by cord plasma PCB-153 levels. We used a validated pharmacokinetic model to estimate monthly infants' levels across the first year of life. Inattention and activity were assessed by coding of video recordings of children undergoing fine motor testing. We used multivariable linear regression to evaluate the association between prenatal and postnatal PCB-153 levels and inattention (n=97) and activity (n=98) at 5years of age. RESULTS: Cord plasma PCB-153 was not associated with inattention and activity. Each interquartile range (IQR) increase in estimated infant PCB-153 levels at 2months was associated with a 1.02% increase in the duration of inattention (95% CI: 0.04, 2.00). Statistical adjustment for the duration of breastfeeding slightly increased regression coefficients for postnatal level estimates, some of which became statistically significant for inattention (months: 2-4) and activity (months: 2-5). CONCLUSIONS: Our study adds to the growing evidence of postnatal windows of development during which children are more susceptible to neurotoxicants like PCBs.

Prenatal and 5-year p,p'-DDE exposures are associated with altered sensory processing in school-aged children in Nunavik: a visual evoked potential study.

Due to their geographic location and traditional diet, rich in seafood and marine mammals, the Inuit living in Arctic Quebec are exposed to high amounts of pollutants, including organochlorine pesticides (OCPs). While the adverse developmental effects of these pesticides on child cognitive functions are well known, the effects of developmental exposure to OP on sensory processes have not been investigated. The aim of this longitudinal study was to assess the effects of prenatal and childhood exposure to 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and its major metabolite 1,1,-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), on visual processing in Inuit children in Nunavik (Arctic Québec). p,p'-DDT and p,p'-DDE concentrations were determined from umbilical cord and 5- and 11-year plasma samples. Visual evoked potentials (VEPs) were successfully recorded in 150 children at 4 contrast levels (95%, 30%, 12%, and 4%). Hierarchical multiple regressions were conducted to determine the association between p,p'-DDT, or p,p'-DDE, exposure and VEPs while controlling for the effects of various confounders, including fish nutrients and other contaminants. p,p'-DDE measured in umbilical cord plasma was significantly related to the amplitude of the N150 response at the lowest contrast (4%). In addition, 5-year p,p'-DDE plasma concentration was significantly associated with decreased N75 amplitude. These findings indicate that p,p'-DDE exposure, both pre- and postnatally, during early childhood is associated with visual processing impairment later in life.