Prenatal Pyrethroid Exposure and Behavioral Problems in 5-Year Old Children from the Infants' Environmental Health Study (ISA)

Background: Pyrethroid insecticides may affect children's behavior, but data from prospective studies are rare. We examined whether prenatal pyrethroid exposure was associated with behavioral problems in 5-year old children from the Infants′ Environmental Health Study (ISA).Methods: We interviewed mothers from 5-year old children (mean 5.7 ± 0.4 years) (n=292) about their child’s behavior during the last two months, administring the Child Behavior Checklist (CBCL). We measured pesticide metabolite concentrations in maternal urine collected 1-3 times during pregnancy: DCCA for the pyrethroids permethrin, cypermethrin, and cyfluthrin, and 3PBA for permethrin, cypermethrin, and deltamethrin. We revised internal consistency of CBCL and analyzed sub-scales with Cronbach-alfa >0.7: Internalizing, Externalizing, Aggressive, Withdrawn behavior. We ran linear regression models for log-10 transformed prenatal metabolite concentrations and CBCL scales, adjusting for child age, child sex, stressful life events, HOME score, parity, maternal education, and maternal depression. We also examined effect-modification by sex.Results: Median (p25-p25) specific gravity-adjusted DCCA and 3PBA concentrations were 1.3 (0.8-2.4) and 0.8 (0.5-1.4) µg/L respectively. Higher DCCA concentrations were associated with increased internalizing problems (ß=2.7, 95%CI -0.2-5.6, per ten-fold increase in exposure), particularly for boys (ß=5.6, 95%CI 1.5-9.6, per ten-fold increase in exposure). Higher 3PBA concentrations were associated with increased externalizing problems (ß=3.0, 95%CI -0.2–6.3, per ten-fold increase in exposure), particularly for boys (ß=5.2, 95%CI 1.1 - 9.9 per ten-fold increase in exposure). For boys, higher 3PBA was also associated with internalizing problems and aggressive behavior: ß=4.4 (95%CI 1.1-8.6) and ß=4.1 (95%CI -0.1-8.3), respectively.Conclusion: Results suggest pyrethroids negatively affect young children’s behavior, effects may be stronger for boys.