Association between gestational and childhood exposures to organophosphate esters and social skill, problem behavior...

Early life exposure to organophosphate esters (OPEs), a class of flame retardants and plasticizers, may be associated with adverse neurobehavioral outcomes. Due to OPEs' relatively short biological half-life in humans, it is important to evaluate exposure-response associations using repeated measures during gestation and childhood. We examined the associations between OPE biomarkers and social skill/problem behavior using data from 236 caregiver-adolescent dyads in the Health Outcomes and Measures of the Environment (HOME) Study. We included urinary concentrations of four OPE biomarkers [bis-2-chloroethyl-phosphate (BCEP), bis(1,3-dichloro-2-propyl)-phosphate (BDCIPP), di-n-butyl-phosphate (DNBP), diphenyl-phosphate (DPHP)] measured up to 9 times (3 in gestation and 6 in childhood) and calculated cumulative exposure measures during gestation, childhood, and the lifetime. Social and behavioral outcomes at age 12 years were assessed using the Social Skills Improvement System (SSiS) completed by adolescents and caregivers. We used quantile g-computation regression to evaluate joint associations between the OPE biomarker mixture and SSiS scores, while adjusting for covariates. Overall, we observed null associations between OPE biomarkers and adolescent social skill/problem behavior scores, but the effect measure modification by adolescent sex was statistically significant. Every quartile increase in childhood/lifetime OPE biomarker mixture was associated with improved caregiver-reported problem behavior among females (Ψ_childhood -3.44 (95%CI: -6.05, -0.84); Ψ_lifetime -3.82 (95%CI: -6.43, -1.22)). Every quartile increase in lifetime OPE biomarker mixture was associated with impaired social skill scores in males (Ψ_lifetime -3.59 (95%CI: -6.79, -0.40). Further studies with a larger sample size will help provide additional insights into OPE exposures early in life and subsequent sex-specific associations with adolescent social skill/problem behavior scores.