Prenatal exposure to glycol ethers and response inhibition in 6-year-old children: The PELAGIE cohort study

Background: Exposure to glycol ethers (GEs) is suspected of impairing neurodevelopment in children, but the specific impact on their inhibitory capacity, a central deficit of ADHD, has never been studied. We aimed to assess the impact of prenatal exposure to GEs on the response inhibition of children aged six years. Methods: In total, 169 mother-child pairs from the French cohort PELAGIE (2002-2006) were studied. Maternal urinary concentrations of six GE metabolites (alkoxycarboxylic acids) were measured during pregnancy. Multiple imputation by quantile regression was used to handle non-detected values and the data were then classified into quartiles. Inhibition of children was evaluated by the Rhythmic Continuous Performance Test 90 (R-CPT90). The inhibition score (percentage of correct responses to non-target stimuli) was corrected for compliance with the instructions (percentage of correct responses to target stimuli). The analysis used a multiple linear regression model, adjusting for confounding factors for each metabolite. Results: Median concentrations of metabolites ranged from 0.02 mg/L (Ethoxyacetic acid, EAA) to 0.39 mg/L (Phenoxyacetic acid, PhAA). The median corrected inhibition score was 37.9% [first quartile: 29.8 - third quartile: 47.9]. We found a negative and statistically significant association between the inhibition score and prenatal urinary EAA concentration (p-trend = 0.03), with a significant coefficient for the third quartile (beta = - 0.064; 95% confidence interval: - 0.121, - 0.007). There were no statistically significant associations for the other five metabolites. Conclusion: These results are consistent with the hypothesis of possible impact of prenatal environmental exposure on inhibitory capacity among children. Data about the GEs metabolized to EAA (history of exposure sources and toxicokinetics) should be gathered to further interpret these results and guide precautionary measures.