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

Abstract

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 (${\mathrm{NO}}_2$) and particulate matter (PM) $\le 2.5\mu m$ in aerodynamic diameter (${\mathrm{PM}}_{2.5}$) 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 ${\mathrm{NO}}_2$ and ${\mathrm{PM}}_{2.5}$ ranged from $8.4\text{to}9.0\text{ppb}$ and $8.4\text{to}9.1{\mu g/m}^3$, 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 ${\mathrm{NO}}_2$ exposures were likely to have more behavioral problems [$\beta$: 1.24; 95% confidence interval (CI): 0.39, 2.08; per $2\text{ppb}$ ${\mathrm{NO}}_2$], particularly ${\mathrm{NO}}_2$ in the first and second trimester. Each $2\text{-}{\mu g/m}^3$ increase in ${\mathrm{PM}}_{2.5}$ 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 ${\mathrm{PM}}_{2.5}$ 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 ${\mathrm{NO}}_2$ and ${\mathrm{PM}}_{2.5}$ in utero and in early life. https://doi.org/10.1289/EHP10248.