Prenatal exposure to PM₁₀ and NO₂ and children's neurodevelopment from birth to 24months of age: Mothers and Children's Environmental Health (MOCEH) study

Introduction: Previous studies have suggested adverse effects of maternal exposure to air pollution on neurodevelopment in early childhood. Objectives: We aimed to investigate the association between prenatal exposure to particulates of less than 10μm in diameter (PM₁₀) and nitrogen dioxide (NO₂) and neurodevelopment in children during the first 24months of their lives. Methods: The MOCEH study is a prospective birth cohort study in South Korea. Average exposure levels to PM₁₀ and NO₂ during the entire pregnancy were estimated using the inverse distance weighting (IDW) method. A total of 520 mother-child pairs who completed neurodevelopmental assessments using the Korean Bayley Scale of Infant Development II (K-BSID-II) more than once at ages of 6, 12 and 24months were included. Mental developmental index (MDI) and psychomotor developmental index (PDI) from the K-BSID-II were used as outcome variables. Results: There were negative associations between maternal exposure to PM₁₀ and MDI (β=-2.83; p=0.003) and PDI (β=-3.00; p=0.002) throughout the first 24months of life as determined by the generalized estimating equation (GEE) model. Maternal NO₂ exposure was related with impairment of psychomotor development (β=-1.30; p=0.05) but not with cognitive function (β=-0.84; p=0.20). In a multiple linear regression model, there were significant effects of prenatal air pollution exposure on MDI (PM₁₀: β=-4.60; p<0.001, NO₂: β=-3.12; p<0.001) and PDI (PM₁₀: β=-7.24; p<0.001, NO₂: β=-3.01; p<0.001) at 6months, but no significant association was found at 12 and 24months of age. Conclusions: The findings suggest that exposure to air pollution may result in delayed neurodevelopment in early childhood.