Exposure to per- and polyfluoroalkyl substances in association with autism spectrum disorder: a case-control study

By H. Shin, D. Bennett, A. Calafat, D. Tancredi, and I. Hertz-Picciotto
Environ. Epi.
November 11, 2019
DOI: 10.1097/01.EE9.0000610080.49619.11

Background/Aim: Per- and polyfluoroalkyl substances (PFAS), a group of synthetic compounds widely used in industrial and consumer products, have shown neurologic or neuro-developmental toxicity in experiments with laboratory animals. In humans, associations between exposures to PFAS and neurodevelopmental or behavioral problems are somewhat inconclusive. The goal of this study was to determine whether in utero exposure or child’s early life exposure to PFAS was associated with an increased risk of autism spectrum disorder (ASD).

Methods: Participants were 453 mother-child pairs from CHARGE (CHildhood Autism Risk from Genetics and Environment), a population-based case-control study. Children were clinically confirmed for ASD (n = 239) or typical development (TD, n = 214). As a proxy for in utero or child’s early life exposures, we quantified nine PFAS in maternal serum samples collected when their child was 2 to 5 years old and used the ln-transformed concentrations to reduce the influence of outliers. We used logistic regression to evaluate the association of maternal PFAS concentrations with ASD.

Results: Perfluorohexane sulfonate (PFHxS) was statistically significantly associated with an increased risk of ASD (per natural-log nanogram per milliliter increase: odds ratio (OR) = 1.48; 95% confidence interval (CI): 1.03, 2.12). When concentrations were categorized by quartile and compared to the lowest quartile (reference category), we observed positive associations with ASD risk for being in the highest quartile of perfluorooctane sulfonate (PFOS) and PFHxS with ASD risk (OR = 2.06; 95% CI: 1.00, 4.26 [PFOS]; OR = 1.97; 95% CI: 1.09, 3.58 [PFHxS]).

Conclusions: In this study, we found that in utero exposure or child’s early life exposure to PFAS might increase the risk of ASD. Further studies will be useful to confirm these findings with direct exposure measures prospectively collected from mothers and children at an earlier developmental stage than the current study.

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