Early Life Exposure to Perfluoroalkyl Substances (PFAS) and ADHD: A Meta-Analysis of Nine European Population-Based Studies

Abstract

INTRODUCTION: To date, the evidence for an association between perfluoroalkyl substances (PFAS) exposure and attention deficit and hyperactivity disorder (ADHD) is inconclusive. OBJECTIVE: We investigated the association between early life exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), and ADHD in a collaborative study including nine European population-based studies, encompassing 4,826 mother-child pairs. METHODS: Concentrations of PFOS and PFOA were measured in maternal serum/plasma during pregnancy, or in breast milk, with different timing of sample collection in each cohort. We used a validated pharmacokinetic model of pregnancy and lactation to estimate concentrations of PFOS and PFOA in children at birth and at 3, 6, 12, and 24 months of age. We classified ADHD using recommended cutoff points for each instrument used to derive symptoms scores. We used multiple imputation for missing covariates, logistic regression to model the association between PFAS exposure and ADHD in each study, and combined all adjusted study-specific effect estimates using random-effects meta-analysis. RESULTS: A total of 399 children were classified as having ADHD, with a prevalence ranging from 2.3% to 7.3% in the studies. Early life exposure to PFOS or PFOA was not associated with ADHD during childhood [odds ratios (ORs) ranging from 0.96 (95% CI: 0.87, 1.06) to 1.02 (95% CI: 0.93, 1.11)]. Results from stratified models suggest potential differential effects of PFAS related to child sex and maternal education. CONCLUSION: We did not identify an increased prevalence of ADHD in association with early life exposure to PFOS and PFOA. However, stratified analyses suggest that there may be an increased prevalence of ADHD in association with PFAS exposure in girls, in children from nulliparous women, and in children from low-educated mothers, all of which warrant further exploration.

Thyroid Disrupting Effects of Old and New Generation PFAS

“…Some studies showed only weak to moderate associations between child's behavior and prenatal PFOA, PFNA, and PFDA exposure (96). A recent investigation of nine European cohorts with a total of 4,826 mother-child pairs found overall no associations between prenatal and early postnatal (up to 24 months of age) PFOS and PFOA exposure and ADHD risk (97). Up to now, only a very recent study by Luo et al addressed the issue of the role of thyroid hormone perturbations as the mechanism through which PFAS would impair neurodevelopment in children (79).…”

Antioxidative Molecules in Human Milk and Environmental Contaminants

“…Early life exposure to PFASs in human milk has been correlated in 2020 to different negative outcomes in infants, although further studies are necessary to confirm the first and so far weak evidence from very few studies [ 183 ]. A European-based meta-analysis including more than 4800 mother–child dyads suggested an increased prevalence of attention-deficit/hyperactivity disorder (ADHD) linked to PFAS exposure in girls, in children from nulliparous women and in children from low-educated mothers [ 183 ]. A small Chinese cohort of 174 mother-infant pairs correlated PFAS exposure via human milk and negative outcomes in postnatal growth, particularly infants’ length and weight gain rates [ 127 ].…”

Associations of Maternal Stress, Prenatal Exposure to Per- and Polyfluoroalkyl Substances (PFAS), and Demographic Risk Factors with Birth Outcomes and Offspring Neurodevelopment: An Overview of the ECHO.CA.IL Prospective Birth Cohorts

“…These chemicals pass through the placenta and can affect the developing fetus [ 13 , 14 ], leading to adverse birth outcomes [ 15 , 16 , 17 ]. Prenatal exposure to PFAS and non-chemical stressors also has been linked to impaired cognition in childhood [ 10 , 18 , 19 ]. However, these associations have been inconsistent across study populations.…”