Prenatal exposure to benzophenones, parabens and triclosan and neurocognitive development at 2 years

Benzophenones (BPs), parabens, and triclosan (TCS) are widely used in personal care products and may be neurotoxic to children, but limited studies have estimated the associations between exposure to these potential endocrine disrupting chemicals during pregnancy and child neurocognitive development.

Our aim was to evaluate the relationships of prenatal exposure to BPs, parabens and TCS with child neurocognitive development at age 2.

From 2014 to 2015, 478 mother-child pairs from a longitudinal prenatal cohort in China were included in present study. We quantified BPs, parabens and TCS in three spot urine samples during pregnancy (in the first, second, and third trimester). The Bayley Scales of Infant Development (BSID) test to children was performed at 2 years. Multivariate linear regression models and generalized estimating equations were used to examine changes in mental developmental index (MDI) and psychomotor development index (PDI) per 2-fold increase in averaged and trimester-specific maternal urinary phenols, respectively.

In the adjusted models, each 2-fold increase in average prenatal paraben concentration was associated with lower MDI scores among girls [-1.08 (95% CI: -2.10, -0.06) and - 1.51 (95% CI: -2.69, -0.32) for methyl paraben (Mep) and Σparabens, respectively], but the association was not statistically significant among boys [-0.24 (95% CI: -1.46, 0.99), P_sex-int = 0.37 and 0.18 (95% CI: -1.28, 1.64), P_sex-int = 0.10 for Mep and Σparabens, respectively]. Increasing urinary 4-hydroxybenzophenone (4-OH-BP) concentration was associated with lower PDI scores among boys [-2.96 (95% CI: -4.48, -1.45)], not girls [-0.07 (95% CI: -1.57, 1.43)] and the association was significantly different in boys and girls (P_sex-int = 0.01). No significant associations were observed between the average prenatal TCS exposure and BSID results. In trimester-specific analyses, increasing parabens was associated with lower girls' MDI only in the second trimester, while increasing 4-OH-BP was associated with lower boys' PDI in each trimester.

Our results suggest that prenatal exposure to BPs and parabens may be associated with impairment in child cognitive abilities at 2 years. Further human and animal studies are needed to verify our results and elucidate the biological mechanisms involved in these associations.