Prenatal exposure to air pollution is associated with childhood inhibitory control and adolescent academic achievement.

backgroundPrenatal air pollution exposure is associated with reductions in self-regulation and academic achievement. Self-regulation has been separately linked with academic achievement. Understudied, however, are the contributions of pollution exposure to inhibitory control, a facet of self-regulation, and whether pollution-related inhibitory control deficits are associated with impairment in academic achievement.

methodsParticipants were recruited from a prospective birth cohort. Measures of prenatal airborne polycyclic aromatic hydrocarbons (PAH) during the third trimester of pregnancy, inhibitory control (NEPSY Inhibition) at mean age = 10.4 years, and Woodcock-Johnson Tests of Achievement-III at mean age = 13.7 were available for N = 200 participants. Multiple linear regression examined sex-dependent and sex independent associations among prenatal PAH, childhood inhibitory control, and academic achievement during adolescence, and whether childhood inhibitory control mediated associations between prenatal PAH and academic achievement during adolescence, controlling for ethnicity, maternal country of birth, language of prenatal interview, maternal marital status, maternal years of education, material hardship, quality of home caregiving environment, and early life stress.

resultsAcross all participants, higher prenatal PAH was significantly associated with worse spelling skills (WJ-III Spelling, β = -0.16, 95%Confidence Interval [CI]: 0.30, -0.02, p = .02). Trend level associations between higher prenatal PAH and worse reading comprehension (WJ-III Passage Comprehension, β = -0.13, 95%CI: 0.28, 0.01, p = .07) and math skills (WJ-III Broad Math, β = -0.11, 95%CI: 0.25, 0.03, p = .11) were detected. Across all participants, higher PAH was significantly associated with worse inhibitory control (β = -0.15, 95%CI: 0.29,-0.01 p = .03). Better inhibitory control was significantly associated with better reading comprehension (WJ-III Passage Comprehension, β = 0.22, 95%CI: 0.09, 0.36, p < .002) and math skills (WJ-III Broad Math Index, β = 0.32, 95%CI: 0.19, 0.45, p < .001), and trend level associations with better spelling skills (WJ-III Spelling, β = 0.12, 95%CI: 0.02, 0.26, p = .10). Inhibitory control significantly mediated PAH-related achievement effects for Passage Comprehension (β = -0.61, 95%CI: 1.49, -0.01) and Broad Math Index (β = -1.09, 95%CI: 2.36, -0.03).

conclusionsHigher prenatal PAH exposure and lower childhood inhibitory control were associated with worse spelling, passage comprehension, and math in adolescence. Notably, childhood inhibitory control mediated PAH exposure-related effects on achievement in adolescents. Identifying these potential exposure-related phenotypes of learning problems may promote interventions that target inhibitory control deficits rather than content specific deficits.