Associations of Pre- and Postnatal Air Pollution Exposures with Child Behavioral Problems and Cognitive Performance: A U.S. Multi-Cohort Study.

Background: Population studies support the adverse associations of air pollution exposures with child behavioral functioning and cognitive performance, but few studies have used spatiotemporally resolved pollutant assessments.
Objectives: We investigated these associations using more refined exposure assessments in 1,967 mother-child dyads from three U.S. pregnancy cohorts in six cities in the ECHO-PATHWAYS Consortium.
Methods: Pre- and postnatal nitrogen dioxide ( NO 2 ) and particulate matter (PM) ≤ 2.5 μ m in aerodynamic diameter ( PM 2.5 ) exposures were derived from an advanced spatiotemporal model. Child behavior was reported as Total Problems raw score using the Child Behavior Checklist at age 4-6 y. Child cognition was assessed using cohort-specific cognitive performance scales and quantified as the Full-Scale Intelligence Quotient (IQ). We fitted multivariate linear regression models that were adjusted for sociodemographic, behavioral, and psychological factors to estimate associations per 2-unit increase in pollutant in each exposure window and examined modification by child sex. Identified critical windows were further verified by distributed lag models (DLMs).
Results: Mean NO 2 and PM 2.5 ranged from 8.4  to  9.0  ppb and 8.4  to  9.1   μ g / m 3 , respectively, across pre- and postnatal windows. Average child Total Problems score and IQ were 22.7 [standard deviation (SD): 18.5] and 102.6 (SD: 15.3), respectively. Children with higher prenatal NO 2 exposures were likely to have more behavioral problems [ β : 1.24; 95% confidence interval (CI): 0.39, 2.08; per 2  ppb NO 2 ], particularly NO 2 in the first and second trimester. Each 2 - μ g / m 3 increase in PM 2.5 at age 2-4 y was associated with a 3.59 unit (95% CI: 0.35, 6.84) higher Total Problems score and a 2.63 point (95% CI: - 5.08 , - 0.17 ) lower IQ. The associations between PM 2.5 and Total Problems score were generally stronger in girls. Most predefined windows identified were not confirmed by DLMs.
Discussion: Our study extends earlier findings that have raised concerns about impaired behavioral functioning and cognitive performance in children exposed to NO 2 and PM 2.5 in utero and in early life. https://doi.org/10.1289/EHP10248.