Ambient air pollution, psychological stress, and early childhood respiratory outcomes: Modifying effects of prenatal maternal diet, sex, and race/ethnicity

Abstract

BACKGROUND AND AIM: Many lower income, racially/ethnically mixed communities experience co-occurring environmental hazards (i.e., pollutants, social inequities and related stress, poorer access to healthy foods) contributing to respiratory disease. Starting {in utero}, fine particulate matter (PM₂.₅) and stress disrupt similar but not completely overlapping processes, including oxidative stress, influencing respiratory health. Antioxidant intake can have protective effects. We examined associations among prenatal PM₂.₅, maternal stress, and antioxidant intake in relation to early childhood wheeze in a longitudinal pregnancy cohort in the Northeastern United States (N=539). METHODS: Daily prenatal PM₂.₅ exposure was estimated using a satellite-based spatiotemporally resolved model. Women completed the Lifetime Stressor Checklist-Revised (LSC-R). A prenatal antioxidant index (AI) was based on average percentile intake of beta-carotene, vitamins (A,C,E), zinc, magnesium, and selenium. Mothers reported child wheeze with follow-up to 4.1±2.8 years. Logistic regression was used to examine effects of prenatal AI and LSC-R on repeated wheeze (≥2 episodes); effect modification was explored in stratified models. Bayesian distributed lag interaction models (BDLIMs) were used to examine associations between prenatal PM₂.₅ exposure on wheeze, and effect modification by AI, race/ethnicity, and child sex. Covariates included maternal age, education, asthma, and temperature. RESULTS:Women were 39.3% black and 33% Hispanic with 35.6% reporting ≤high school education; 20.3% of children had repeated wheeze. The association between higher AI and decreased wheeze was significant only in blacks (Odds Ratio, OR=0.37, 95% confidence interval, CI: 0.19-0.73 per interquartile range increase). Higher stress was associated with repeated wheeze when AI was below the median, especially among blacks/Hispanics [OR=1.04 (1.01-1.06)]. BDLIMs found that cumulative effect on repeated wheeze per μg/m³ increase in PM₂.₅ across pregnancy was only significant in boys born to black mothers with low antioxidant intake [OR=1.2 (1.01-1.59)]. CONCLUSIONS:Relationships among prenatal PM₂.₅, stress, antioxidant intake, and child wheeze are complex and are modified by race/ethnicity and child sex. KEYWORDS: particulate matter, prenatal stress, nutrition, antioxidants, pediatric respiratory outcomes