Child neurodevelopment is related to maternal manganese exposure: A Taiwan national prospective cohort study.

AIM: Prenatal exposure to air pollutants has been linked to developmental delays in early childhood. This study investigated the association between prenatal exposure to ambient manganese (Mn) and delays in achieving specific neurodevelopmental milestones. METHOD: Data were obtained from a nationwide population-based cohort study that recruited children born in 2005 and their mothers. Developmental outcomes were assessed by conducting home interviews at 6 and 18 months of age. Gestational exposure to ambient Mn was estimated using a land-use regression model enhanced with machine learning. Associations between Mn exposure and delayed milestone attainment were evaluated using multivariable logistic regression, adjusting for child, maternal, household factors, and co-exposure to particulate matter and nitrogen dioxide. RESULTS: A total of 17,683 term singleton births without congenital anomalies were included. Mn exposure during mid-gestation showed more consistent associations with later attainment of selected developmental milestones. After adjustment for relevant covariates, each 1 ng/m³ increase in second-trimester Mn exposure was associated with higher odds of delayed gross motor, fine motor, language, and social milestones ("walking with support": adjusted odds ratio [aOR] = 1.028; 95% confidence interval [CI]: 1.004-1.053), fine motor skills ("drawing arbitrarily": aOR = 1.081; 95% CI: 1.053-1.109), language milestones ("waving goodbye": aOR = 1.048; 95% CI: 1.022-1.075; "calling a parent meaningfully": aOR = 1.050; 95% CI: 1.021-1.080), and social interaction ("drinking with both hands": aOR = 1.045; 95% CI: 1.021-1.071). CONCLUSION: These findings suggest modest associations between prenatal ambient Mn exposure, particularly during mid-gestation, and early neurodevelopmental timing.