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.
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Contributors J-FV performed the statistical analyses, and drafted the manuscript, assisted by CC. CC conceived and planned the study, assisted by SC. All authors were involved in the interpretation of the data, revision of the manuscript for important intellectual content, and final approval of the manuscript.
Funding This study was supported by the French National Research Agency (ANR-2010-PRSP-007), the French Pfizer Foundation, and the French Research Institute for Public Health (AMC11004NSA-DGS). The funders had no role in the design or conduct of this study, the analysis or interpretation of the data, or the preparation of this manuscript.
Competing interests None.
Patient consent Obtained.
Ethics approval The French Consulting Committee for the Treatment of Information in Medical Research and the French National Commission for the Confidentiality of Computerised Data approved this study.
Provenance and peer review Not commissioned; externally peer reviewed.
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