The relationship between prenatal perfluorine and polyfluoroalkyl substances (PFAS) exposure and infant neurodevelopment: Modifying effects of DHA revised

Abstract

Background: It has been found that prenatal perfluorine and polyfluoroalkyl substances (PFAS) exposure can affect infant neurodevelopment. On the other hand, docosahexaenoic acid (DHA) supplementation can improve neurodevelopment, but studies on whether it can improve neurodevelopmental delay caused by prenatal PFAS exposure are limited.

Objective: This study aimed to investigate the relationship between prenatal PFAS exposure and infant neurodevelopmental delay and evaluate the effects of postnatal DHA supplementation on infant neurodevelopment.

Methods: From October 2020 to December 2022, 2415 mother-newborn pairs were enrolled in the study from China WuHu Birth Cohort Study (WH-BC). Six PFAS (PFOA, PFOS, PFNA, PFBS, PFHxS and PFHxA) were measured in maternal urine samples using liquid chromatography-mass spectrometry (LC-MS/MS). Infant neurodevelopment was assessed at 6 and 12 months using the Ages and Stages Questionnaire (ASQ-3) score. Generalised linear models (GLMs) and Bayesian kernel machine regression (BKMR) were used to evaluate the associations between single or mixed PFAS exposure and infant neurodevelopment. Generalized estimating equations (GEEs) were used to identify the sensitive time window for the effect of prenatal exposure to PFAS on infant neurodevelopment. Stratified analysis was used to investigate the potential effect of postnatal DHA supplementation on infant neurodevelopment.

Results: In the gross motor domain, there was a significant positive association between child development delay at 6 months of age and first-trimester PFOA (1st tri: OR = 1.97, 95 % CI: 1.20, 3.24) as well as second-trimester PFNA (2nd tri: OR = 1.61, 95 % CI: 1.03, 2.52). Similarly, at 12 months of age, there were significantly and positively associated between second-trimester exposure levels of PFNA (OR = 1.98, 95 % CI: 1.14, 3.45), PFBS (OR = 1.63, 95 % CI: 1.04, 2.55) and children's developmental delay. We found significant association between prenatal exposure to PFAS and increased children's developmental delay after adjusting for confounders, and the critical exposure windows of PFAS were the first-trimester and second-trimester of pregnancy. Prenatal PFAS exposure affected neurodevelopmental domains differently in infants of different sexes, with PFAS exposure mainly affecting fine domain development in boys and communication and gross motor domains in girls. The children's developmental delay associated with exposure to PFAS could be attenuated by DHA supplementation during lactation in mother-child pairs with PFAS. Whereas in the DHA unsupplemented group, PFAS exposure increased the risk of neurodevelopment. There was a significant and positive association between PFOA (1st tri: OR = 1.68, 95 % CI: 1.09, 2.60) and PFNA (1st tri: OR = 1.43, 95 % CI: 1.01, 2.03;2nd tri: OR = 1.61, 95 % CI: 1.06, 2.45) with developmental delay at 6 months of age.

Conclusions: PFAS exposure was associated with developmental delays, with gender differences observed, and female infants are more vulnerable. Infant neurodevelopmental delay caused by prenatal PFAS exposure can be alleviated by postnatal DHA supplementation. These findings offer important directions for future research and may have implications for public health policy development.

Keywords: DHA; Infants; Neurodevelopmental; PFAS.