Behavioral outcomes and exposure to perfluoroalkyl substances among children aged 6-13 years: The TEDDY child study

Abstract Background Although some studies report that exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy and early life stages of a child could adversely impact neurodevelopment, literature shows mixed evidence. Objectives Using an ecological framework for human development, we assessed the association of risk factors for environmental PFAS exposure and childhood PFAS concentrations with behavioral difficulties among school-age children exposed to PFAS from birth, while also controlling for the important influence of the parenting and familial environment. Methods The study participants included 331 school-age children (6–13 years) born in a PFAS-contaminated area in the Veneto Region (Italy). We study the associations between environmental risk factors of maternal PFAS exposure (residential time, consumption of tap water, residence in Red zone A or B), and breastfeeding duration with parent assessments of children's behavioral problems (using the Strengths and Difficulties Questionnaire [SDQ]), adjusting for socio-demographic, parenting and familial variables. The direct relationships between serum blood PFAS concentrations and SDQ scores was evaluated in a subset of children (n = 79), both with single PFAS and weighted quantile sum (WQS) regressions. Results Poisson regression models reported positive associations between high consumption of tap water and externalizing SDQ scores (Incidence Rate Ratio [IRR]: 1.18; 95% confidence interval [CI]: 1.04–1.32) and total difficulty scores (IRR: 1.14; 95% CI: 1.02–1.26). Childhood perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) were associated with higher internalizing SDQ scores (4th vs. 1st quartile, PFOS IRR: 1.54, 95% CI: 1.06–2.25), externalizing scores (4th vs. 1st quartile, PFHxS IRR: 1.59, 95% CI: 1.09–2.32), and total difficulty scores (4th vs. 1st quartile, PFOS IRR: 1.37, 95% CI: 1.05–1.71; PFHxS IRR: 1.54, 95% CI: 1.09–1.90). The WQS regressions confirmed the associations reported by single-PFAS analyses. Conclusions We observed cross-sectional associations of tap water consumption and childhood PFOS, and PFHxS concentrations with greater behavioral difficulties.