Association between prenatal and early postnatal exposure to perfluoroalkyl substances (PFAS) and IQ score in 7-year-old children from the Odense Child Cohort.

Abstract

Perfluoroalkyl substances (PFAS) are persistent chemicals capable of crossing the placenta and passing into breastmilk. Evidence suggests that PFAS exposure may affect brain development. We investigated whether prenatal or early postnatal PFAS exposure was associated with IQ-scores in schoolchildren from the Odense Child Cohort, Denmark 2010 to 2020. We assessed perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) concentrations in maternal serum collected in the 1st trimester of pregnancy and in child serum at age 18 months. At 7 years of age children completed an abbreviated version of Wechsler Intelligence Scale for Children version-V (WISC-V) from which Full Scale Intelligence Quotient (FSIQ) and Verbal Comprehension Index (VCI) were estimated. In multiple linear regressions among 967 mother-child pairs a doubling in maternal PFOS and PFNA concentrations was associated with lower FSIQ, while no significant associations were observed for PFOA, PFHxS or PFDA. PFAS concentrations at 18 months and duration of breastfeeding were strongly correlated and even in structural equation models it was not possible to differentiate the opposite effects of PFAS exposure and duration of breastfeeding on FSIQ. As PFAS exposure is ubiquitous association with even a small reduction in IQ is of public health concern.