Prenatal Persistent Exposure to Organophosphate Esters and Early Childhood Brain Development: A Longitudinal Analysis

Previous studies on the prenatal organophosphate ester (OPE) exposure's effect on children's neurodevelopment have yielded inconsistent results. In this study, we employed a longitudinal approach, capitalizing on multitime-point evaluations of exposure to OPEs and two-stage assessments of children's brain development. The study included 508 mother-child pairs. We measured seven OPEs in maternal serum throughout pregnancy and assessed children's mental health and developmental milestones at the age of 2 and 5. The group-based trajectory model identified pregnancy exposure trajectories. Generalized estimated equations and quantile-based g-computation were employed to evaluate the effects of OPEs on children's brain development. Four OPEs, including 2-ethylhexyl diphenyl phosphate (EHDPP), were detected in over 50% of the maternal samples. Each ln-unit increment of EHDPP was associated with an increased peer problem scores (IRR: 1.104, 95% CI: 1.038-1.174) in mental health. Regarding development milestones, EHDPP was related to lower scores in communication, gross motor, personal-social, and total score of the ages and stages questionnaires (ASQ) (IRR: 0.963-0.976). Trajectory analysis confirmed these associations. Notably, boys were more affected in terms of mental health, while girls were more vulnerable in terms of developmental milestones. Prenatal exposure to OPEs, particularly EHDPP, is associated with adverse brain development in early childhood with notable sex-specific differences in vulnerability.