J Allergy Clin Immunol 2015 Jan 6;135(1):228-35. Epub 2014 Oct 6.
Department of Medicine, University of California, San Francisco (UCSF), San Francisco, Calif; Department of Bioengineering and Therapeutic Sciences, UCSF, San Francisco, Calif.
Background: Childhood asthma prevalence and morbidity varies among Latinos in the United States, with Puerto Ricans having the highest and Mexicans the lowest.
Objective: To determine whether genetic ancestry is associated with the odds of asthma among Latinos, and secondarily whether genetic ancestry is associated with lung function among Latino children.
Methods: We analyzed 5493 Latinos with and without asthma from 3 independent studies. For each participant, we estimated the proportion of African, European, and Native American ancestry using genome-wide data. We tested whether genetic ancestry was associated with the presence of asthma and lung function among subjects with and without asthma. Odds ratios (OR) and effect sizes were assessed for every 20% increase in each ancestry.
Results: Native American ancestry was associated with lower odds of asthma (OR = 0.72, 95% CI: 0.66-0.78, P = 8.0 × 10(-15)), while African ancestry was associated with higher odds of asthma (OR = 1.40, 95% CI: 1.14-1.72, P = .001). These associations were robust to adjustment for covariates related to early life exposures, air pollution, and socioeconomic status. Among children with asthma, African ancestry was associated with lower lung function, including both pre- and post-bronchodilator measures of FEV1 (-77 ± 19 mL; P = 5.8 × 10(-5) and -83 ± 19 mL; P = 1.1 x 10(-5), respectively) and forced vital capacity (-100 ± 21 mL; P = 2.7 × 10(-6) and -107 ± 22 mL; P = 1.0 x 10(-6), respectively).
Conclusion: Differences in the proportions of genetic ancestry can partially explain disparities in asthma susceptibility and lung function among Latinos.