Urinary organophosphate insecticide metabolite concentrations during pregnancy and children's interpersonal, communication, repetitive, and stereotypic behaviors at 8 years of age: The home study

Abstract

Background Prenatal exposure to organophosphate insecticides may be associated with autism spectrum disorders and related behaviors. This association may be modified by single nucleotide polymorphisms in the paraoxonase (PON1) enzyme. Objective We examined the relationship of prenatal organophosphate insecticide biomarkers with reciprocal social, repetitive, and stereotypic behaviors in 8-year old children, and modification of this relationship by child PON1 polymorphisms. Methods Among 224 pregnant women, we quantified concentrations of six nonspecific dialkyl phosphate (DAP) metabolites of organophosphate insecticides in two urine samples collected at ~16 and ~26 weeks gestation. When children were eight years old, we administered the Social Responsiveness Scale (SRS), a continuous measure of various dimensions of interpersonal behavior, communication, and repetitive/stereotypic behaviors. We estimated the association between a 10-fold increase in the sum of six DAP concentrations (ΣDAP) and SRS scores. We examined whether child PON1192 and PON1–108 genotypes modified this association. Results After covariate adjustment, ΣDAP concentrations were not associated with SRS scores [β=–1.2; 95% confidence interval (CI): –4.0, 1.6]. Among children with the PON1–108TT genotype, ΣDAP concentrations were associated with 2.5-point higher (95% CI: −4.9, 9.8) SRS scores; however, the association was not different from the 1.8-point decrease (95% CI: −5.8, 2.2) among children with PON1–108CT/CC genotypes (ΣDAP × PON1–108 p-value =0.54). The association between ΣDAP concentrations and SRS scores was not modified by PON1192 (ΣDAP × PON1192 p-value =0.89). Conclusions In this cohort, prenatal urinary DAP concentrations were not associated with children's social behaviors; these associations were not modified by child PON1 genotype.