Associations between maternal urinary metabolite concentrations of selected volatile organic compounds and child neurocognitive development at two years of age.

Abstract

BACKGROUND Neurotoxicity of exposure to volatile organic compounds (VOCs) has been documented in animal studies, but related epidemiological investigations are very limited; particularly, those based on biomonitoring data are not available yet. OBJECTIVES This study aimed to evaluate the trimester-specific association between maternal urinary concentrations of multiple VOC metabolites (mVOCs) and child neurodevelopment. METHODS Twenty mVOCs were measured in urine samples repeatedly collected at the first, second, and third trimesters from 1,023 pregnant women in Wuhan, China. The Bayley Scales of Infant and Toddler Development (Chinese Revision) was used to assess children's neurocognitive development at two years old. General linear models and generalized estimating equations were used to analyze the associations of individual urinary mVOC concentrations with children's neurodevelopment. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to evaluate the effect of the mVOC mixture on children's neurodevelopment. RESULTS Risk assessment showed that the average hazard quotients of cyanide, 1,3-butadiene, and acrolein during pregnancy exceeded the recommended safety thresholds in more than 90% women. Higher urinary concentration of 2-aminothiazoline-4-carboxylic acid (ATCA, metabolite of cyanide) was associated with lower child mental development index (MDI) score, and the association was significant at the first trimester among males. Each interquartile ratio-fold increase in the urinary concentration of ATCA at the first trimester was associated with a decrease of 4.25 points (95% confidence interval: -6.57, -1.94) in males' MDI score. Additionally, WQS regression and BKMR analyses suggested that the mVOC mixture was significantly associated with lower MDI in males, and the association was mainly driven by ATCA. CONCLUSIONS Exposure to cyanide at environmentally relevant doses may impact neurodevelopment, particularly among males. Early pregnancy appeared to be the sensitive window of the exposure. Further studies are needed to confirm these findings. Corresponding measures need to be taken to reduce gestational exposure to cyanide. https://doi.org/10.1289/EHP15539.