Less air pollution previously related to clean air and climate policies is linked to improved cognitive scores over time in NYC children

Abstract

Prenatal and postnatal exposure to air pollution has been associated in multiple epidemiological studies with adverse neurodevelopmental outcomes in children, including in New York City cohorts. Studies are lacking on changes in associations between air quality and neurodevelopmental outcomes over recent decades that have been marked by improvement in air quality. Here we investigated whether decreased prenatal exposure to air pollution, previously linked to clean air and climate policies in New York City, benefited cognitive development in children participating in cohort studies of the Columbia Center for Children’s Environmental Health between 1998 and 2020. Information from such studies can benefit public health policy. We utilized data on prenatal exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO 2 ) and polycyclic aromatic hydrocarbons (PAH) in successive longitudinal cohort studies. PM2.5 and NO 2 were available in the first two cohorts (1998–2016); PAH were monitored in three cohorts (1998–2020). Children were assessed for cognitive development at ages 1, 2, and 3 using the Bayley Scales of Infant and Toddler Development (BSID-II), which provided Mental Development Index (MDI) scores. To test associations between air pollutant exposures and MDI, we used linear regression, adjusting for demographic and other factors that contribute to neurodevelopment and/or changed over time. Across the cohorts, levels of prenatal exposure to PM2.5, NO 2 , and PAH decreased significantly; and there was a significant upward trend in MDI scores ( N = 1109). Overall, when combining samples from cohorts, the pollutants were significantly and inversely associated with MDI at 1, 2, and 3 years. In the cohort-specific analyses, significant inverse associations between prenatal exposure to PM2.5, NO 2 , PAH and 3-year MDI were seen in the larger initial cohort ( N > 700, enrolled between 1998 and 2006) that experienced the highest exposure and the greatest decrease in levels of air pollutants. Weaker, albeit inverse, associations were observed between PM2.5 and cognitive development of children in the later cohort (2008–2016) who experienced lower exposure. These results indicate that, during the period of the largest reduction in air pollution levels, previously associated with air pollution and climate policies enacted in NYC, children’s scores on cognitive tests improved, providing new evidence that such policies are beneficial to children’s neurodevelopment.