Children’s Behavioral and social impairment in relation to prenatal exposure to phthalates

Abstract

Purpose: Phthalates are non-persistent endocrine disrupting chemicals whose relationship with children’s neurodevelopment has not been fully elucidated. This study examines the relationship between prenatal phthalate exposure and potential adverse effects on child behavior. Methods: We assessed behavioral and social impairment in 3 year old children from a Canadian prospective cohort using the parents report of the Behavior Assessment System for Children-2 (BASC-2; n=815), and the Social Responsiveness Scale-2 (SRS-2; n=556). We measured 11 phthalates metabolites in maternal urine during the first trimester of pregnancy. We used multivariable linear regression to estimate the covariate-adjusted differences in child behavior scores with a doubling in di-2-ethylhexyl (DEHP), Mono butyl (MBP), Mono benzyl (MBzP), Mono ethyl (MEP), and Mono-3-carboxypropyl (MCPP) phthalates concentrations. We also examined sex-specific associations of phthalates and behaviors. Results: No consistent associations were observed with the BASC scores. Regarding the SRS, higher MBP and MCPP concentrations were significantly associated with poorer scores of social cognition. MCPP was further associated with poorer scores of social communication. For example, a doubling in MBP concentration was associated with 0.29 points (95% CI: 0.07, 0.51) worse scores in social cognition. In further analyses, sex modified associations between MBP and MEP concentrations, and social cognition, social communication, and total SRS scores, with worse scores in boys and better scores in girls (p-interaction<0.05). For instance, a doubling in MBP concentration was associated with 0.35 (95% CI: 0.09, 0.61) and 0.27 (95% CI: 0, 0.55) points worse social cognition and total scores in boys, and better scores in girls (β= -0.19, 95% CI: -0.45, 0.07 and -0.04, 95% CI: -0.32, 0.25, respectively). Conclusions: Higher prenatal phthalate concentrations were associated with social impairment in boys, but not girls.