Prenatal exposure to perfluoroalkyl substances (PFASs) and ADHD-related behaviors in 3 year old children

Abstract

Introduction Perfluoroalkyl substances (PFASs) are ubiquitous in human sera, and have been associated with ADHD in some but not all epidemiology studies. Few studies have examined associations between prenatal PFAS exposures and ADHD-related behaviors in children. Methods We measured plasma levels of perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) in first trimester pregnant women from 6 Canadian cities. Child behavior at 3 years was assessed with the Behavioral Assessment System for Children (BASC-2, maternal report). We used linear regression with generalized estimating equations to estimate associations of prenatal log2 PFAS levels with hyperactivity and inattention (mean:50, SD:10), adjusting for maternal age, race, education, income, parity, marital status, smoking during pregnancy, alcohol during pregnancy, folic acid, and child sex (n=790). We also examined differences by child sex. Results Geometric means for PFHxS, PFOA and PFOS in plasma were 1.1, 1.7, and 4.7 ng/mL. PFHxS was significantly associated (p<0.05) with higher scores [β (95% CI)] for hyperactivity [0.3 (0.0, 0.6)] in all children combined. Associations between PFOA and hyperactivity were null with all children combined [0.0 (-0.5, 0.5)], but were highly sex-specific, with lower scores in boys and higher scores in girls [Boys: -0.9 (-1.4, -0.3); Girls: 0.9 (0.2,1.6), p interaction <0.01]. A similar pattern was found for PFOS and hyperactivity [Boys: -0.3 (-0.9, 0.2); Girls: 1.0 (0.3, 1.7), p interaction <0.01]. None of the PFASs were associated with attention scores. Conclusions In a Canadian cohort with low PFAS exposure, PFHxS was associated with higher hyperactivity scores in 3 yr children. PFOA and PFOS were associated with lower hyperactivity scores in boys, and higher hyperactivity scores in girls. No associations were found with attention. Our results suggest that PFASs may be associated with hyperactive-type ADHD behaviors, especially in girls.