Effects of prenatal community violence and ambient air pollution on childhood wheeze in an urban population

Abstract

Background: Prenatal exposures to stress and physical toxins influence children's respiratory health, although few studies consider these factors together.

Objectives: We sought to concurrently examine the effects of prenatal community-level psychosocial (exposure to community violence [ECV]) and physical (air pollution) stressors on repeated wheeze in 708 urban children followed to age 2 years.

Methods: Multi-item ECV reported by mothers in pregnancy was summarized into a continuous score by using Rasch modeling. Prenatal black carbon exposure was estimated by using land-use regression (LUR) modeling; particulate matter with a diameter of less than 2.5 μm (PM2.5) was estimated by using LUR modeling incorporating satellite data. Mothers reported child's wheeze every 3 months. The effects of ECV and air pollutants on repeated wheeze (≥ 2 episodes) were examined by using logistic regression. Interactions between ECV and pollutants were examined.

Results: Mothers were primarily black (29%) and Hispanic (55%), with lower education (62% with ≤ 12 years); 87 (12%) children wheezed repeatedly. In models examining concurrent exposures, ECV (odds ratio [OR], 1.95; 95% CI, 1.13-3.36; highest vs lowest tertile) and black carbon (OR, 1.84; 95% CI, 1.08-3.12; median or greater vs less than median) were independently associated with wheeze adjusting for sex, birth season, maternal atopy, education, race, and cockroach antigen. Associations were similar for PM2.5 (adjusted OR, 2.02; 95% CI, 1.20-3.40). An interaction between ECV with air pollution levels was suggested.

Conclusions: These findings suggest that both prenatal community violence and air pollution can contribute to respiratory health in these urban children. Moreover, place-based psychosocial stressors might affect host resistance such that physical pollutants can have adverse effects, even at relatively lower levels.

Keywords: Community violence; particulate matter; prenatal exposure; prenatal stress; repeated wheeze; traffic air pollution.

Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Figures

Figure 1. Predicted BC levels for ACCESS study participants during pregnancy

This figure demonstrates the predicted BC levels for study participants based on residence during the gestation period. In addition, the locations of monitoring sites used in the model to predict BC levels are presented as black triangles.

Figure 2. Predicted PM2.5 levels for ACCESS study participants during pregnancy

This figure demonstrates predicted PM2.5 levels for study participants based on residence during the gestation period. The 10km × 10km AOD grid used to predict daily PM2.5 levels is also depicted.

Figure 3. Exposure-response relationships of prenatal maternal ECV and prenatal air pollution indicators with children’s repeated wheeze

Penalized spline curves using GAMs demonstrating the relationship of (A) prenatal maternal ECV, (B) prenatal BC level (µg/m 3), and (C) prenatal PM2.5 level (µg/m 3), with log odds of children’s repeated wheeze by age 2 years. Solid lines depict the penalized spline curve while dotted lines indicate the 95% confidence bounds. Models were adjusted for child’s gender, season of birth, maternal race, education, atopy, and household cockroach allergens.

Figure 4. Associations between prenatal maternal ECV and children’s repeated wheeze in analyses stratified by air pollutant levels

This figure demonstrates ORs and 95% CIs for repeated wheeze comparing medium vs. low ECV groups (squares) and high vs. low ECV groups (diamonds), stratified by (A) BC median level (0.38 µg/m3) and (B) PM2.5 median level (11.22 µg/m3). The solid markers indicate the ORs for participants exposed to higher levels (≥median) of air pollution and the hollow markers indicate the ORs for participants exposed to lower levels (<median) of air pollution. Models were adjusted for child’s gender, season of birth, maternal race, education, and atopy.