African Ancestry Predicts Lung Function in Minority Youth with Asthma

African ancestry was a significant predictor of lung function said researchers who also found that small particles from smoke and exhaust (PM2.5), the most common cause of health problems from air pollution, were associated with reduced lung function in a nation-wide study of African American and Latino children with asthma. According to research findings published in the American Thoracic Society journal American Journal of Respiratory and Critical Care Medicine, ancestry predicted lung function, but did not modify the effect that environmental exposures had on lung function.

For example, African ancestry in participants self-identified as Latino did not modify the effects of PM2.5 exposures on lung function to a significant degree. The study, “Air Pollution and Lung Function in Minority Youth with Asthma in the GALA II & SAGE II Studies,” which appeared in the journal’s online edition, is believed to be the first to look at interaction between exposure to pollutants and genetic ancestry on lung function.

Andreas Neophytou, ScD, postdoctoral fellow in the Division of Environmental Health Sciences at UC Berkeley School of Public Health, and colleagues examined health data related to Latino and African Americans age 8-21 years, who participated in the largest gene-environment study of asthma in minority children in the US, namely the GALA II and SAGE II studies. Representing a diverse geographic sample, the 1,968 participants were recruited from Chicago, IL; Bronx, NY; Houston, TX; San Francisco Bay Area, CA; and Puerto Rico.

Asthma is the result of complex gene-environment (GxE) interactions which are incompletely defined, and which vary by race, ethnicity and genetic ancestry. GxE interaction effects have been recognized as a potential source of the “missing heritability” in complex diseases, and evaluation of their contribution to the cause of complex diseases/phenotypes has significantly increased in recent years. However, the increasing asthma prevalence as well as the disparities in asthma prevalence across populations suggests a critical role of GxE in asthma.

“Compared to the general population, African American and Puerto Rican children are at higher risk of developing asthma and the cases are usually more severe, potentially due to the areas in which they live, socioeconomic issues, and genetics,” said Dr. Neophytou. “Now we know that air pollution, specifically PM2.5, poses an additional risk of reduced lung function in this vulnerable population of children.”

The researchers examined air pollution effects on lung function in participants across these regions and assessed the possible interactions with global genetic ancestry.
Despite failing to see any significant modification of exposure effect by genetic ancestry in this study, the researchers believe there is value in considering genetic ancestry as well as self-identified ethnicity when examining exposure and lung function.