Exposure to perfluoroalkyl substances and neurodevelopment in 2-year-old children: A prospective cohort study

Background: Humans are widely exposed to per-and polyfluoroalkyl substances (PFAS). As fetal stage is a critical window for neurodevelopment, it is important to know if in utero exposure to PFAS affects fetal neuro-development. However, previous human studies are both limited and inconsistent. Objectives: To investigate the relationship between PFAS exposure during early pregnancy and the neuro-developmental status at 2 years of age in a prospective cohort study. Methods: We measured 10 PFAS in maternal plasma samples collected prior to 16 weeks of gestation in the Shanghai Birth Cohort Study between 2013 and 2016. Childhood neurodevelopment was assessed at 2 years of age using the Bayley Scales of Infant and Toddler Development-Third Edition (BSID-III). Associations with domain specific scores for individual PFAS were assessed by multiple linear regression and binary logistic regression when scores were dichotomized. Quantile-based g-computation was used to estimate the joint effects of PFAS mixture. Results: A total of 2257 mother-child pairs who had both PFAS and BSID measurements were included in our analyses. The means and standard deviations of comprehensive scores were 115 +/- 22, 96 +/- 15 and 108 +/- 15 for cognition, language, and motor, respectively. In multiple linear regressions, we observed significant negative associations of perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDeA), perfluoroundecanoic acid (PFUnDA) with cognitive scores; PFNA, PFDeA, PFUnDA and perfluorohexanesulfonate (PFHxS) negatively with language scores; and PFNA and PFUnDA negatively with motor scores. Quantile-based g-computation showed that PFAS mixture was significantly associated with decreased cognitive and language scores, with an estimated beta of-2.1 [95% confidence interval (CI):-3.5,-0.7)] and-2.0 (95% CI:-2.9,-1.0) per one quartile increase in PFAS mixture for cognitive and language domains, respectively. PFAS mixture was associated with increased odds of low cognition (adjusted odds ratio [OR] = 1.3, 95% CI:1.0, 1.6) and language scores (OR = 1.2, 95% CI: 1.1, 1.3). Conclusions: PFAS exposure during early pregnancy was significantly associated with the adverse neuro-developmental status at 2 years of age, which raises a serious public health concern.