Gun Violence, African Ancestry, and Asthma: A Case-Control Study in Puerto Rican Children.

Background: Exposure to gun violence and African ancestry have been separately associated with increased risk of asthma in Puerto Rican children.
Objective: The objective of this study was to examine whether African ancestry and gun violence interact on asthma and total IgE in school-aged Puerto Rican children.
Methods: This is a case-control study of 747 Puerto Rican children aged 9 to 14 years living in San Juan, Puerto Rico (n = 472), and Hartford, Connecticut (n = 275). Exposure to gun violence was defined as the child's report of hearing gunshots more than once, and the percentage of African ancestry was estimated using genome-wide genotypic data. Asthma was defined as parental report of physician-diagnosed asthma and wheeze in the previous year. Serum total IgE (IU/mL) was measured in study participants. Multivariate logistic and linear regressions were used for the analysis of asthma and total IgE, respectively.
Results: In multivariate analyses, there was a significant interaction between exposure to gun violence and African ancestry on asthma (P = .001) and serum total IgE (P = .04). Among children exposed to gun violence, each quartile increase in the percentage of African ancestry was associated with approximately 45% higher odds of asthma (95% CI, 1.15-1.84; P = .002) and an approximately 19% increment in total IgE (95% , 0.60-40.65, P = .04). In contrast, there was no significant association between African ancestry and asthma or total IgE in children not exposed to gun violence.
Conclusions: Our results suggest that exposure to gun violence modifies the estimated effect of African ancestry on asthma and atopy in Puerto Rican children.
(Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)