Associations of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) with measures of cognition in 7.5-month-old infants

Abstract

Keywords: PFAS, mixtures, neurodevelopment Background: Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that are of health concern given their persistence in the environment and human body, and transmission to offspring during pregnancy. Studies examining the relationship between PFAS and neurodevelopment are inconclusive and largely have been conducted in older children. In the present study, we examined whether prenatal exposure to a mixture of PFAS was related to cognitive function in infancy. Methods: Pregnant participants were enrolled in the Chemicals in Our Bodies cohort and Illinois Kids Development Study, which together make up the ECHO.CA.IL cohort. Seven PFAS were previously measured in 2nd trimester maternal serum samples and were natural log transformed for analyses. Infant cognition was assessed at 7.5 months using a visual recognition memory task that tracks infant looking behavior using an infrared eye tracker. From the eye-tracking data, we calculated two measures of attention (based on infants shifting their looking between two stimuli, and the time it took them to reach cumulative looking criterion), information processing speed (based on how long infants looked at the stimuli before looking away) during the familiarization trial, and recognition memory (based on infants’ looking at novel compared to the familiar stimulus) in the test trial. Bayesian kernel machine regressions (BKMR) were used to assess joint associations between multiple PFAS and individual cognitive outcomes (N=160). Results: Unexpectedly, prenatal exposure to the PFAS mixture was modestly associated with better attention, as indicated by faster shifts between stimuli, with PFNA, PFOS, PFHxS, and PFUdA contributing the most to the overall mixture effect. Increasing exposure to the PFAS mixture was weakly associated better information processing speed and attention although credible intervals include the null value. Conclusions: Using a visual recognition memory task, we observed little evidence that prenatal PFAS exposure is associated with cognitive function.