Air Pollution Reduces Lung Function in Minority Children with Asthma

Exposure to air pollution caused by smoke and exhaust early in life can lead to reduced lung function in Latino and African American children with asthma, according to a new study.

The adverse effects of exposure to air pollution on lung function are well documented, but there is little evidence available in racial/ethnic minority children.

Researchers led by Andreas M. Neophytou, ScD, a postdoctoral fellow in the Division of Environmental Health Sciences at University of California Berkeley School of Public Health, in Berkeley, CA, examined the effects of air pollution on lung function in 1,449 Latino and 519 African American children with asthma from five different geographical regions across the mainland US and Puerto Rico. They 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-the GALA II and SAGE II studies.

The researchers found that African ancestry was a significant predictor of lung function and small particles from smoke and exhaust (PM2.5) were associated with reduced lung function. A 5 μg/m³ increase in average lifetime PM2.5 exposure was associated with a 7.7 % decrease in forced expired volume in one second in the overall study population.

The study results were published online Jan 6, 2016 in the American Journal of Respiratory and Critical Care Medicine.

“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 Neophytou. “Now we know that air pollution, specifically PM2.5, poses an additional risk of reduced lung function in this vulnerable population of children.”

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.

“This is the first study to report an association between exposure to fine particulate matter and reduced lung function in minority children in which racial/ethnic status was measured by genome-wide genetic ancestry,” said Neophytou.

Asthma is believed to be the result of complex interactions between genes and the environment, and varies by race, ethnicity, and genetic ancestry. The interaction of the effects of genes and the environment has been recognized as a potential source of the “missing heritability” in complex diseases. The contribution of genes and the environment to the phenotypes of complex diseases has been evaluated recently. The increasing prevalence of asthma as well as the disparities in asthma prevalence across populations suggests a critical role of genes and the environment in asthma.

The researchers believe there is value in considering genetic ancestry as well as self-identified ethnicity when examining exposure to air pollution and the resulting lung function.

Source:

Neophytou AM, White MJ, Oh SS. Air pollution and lung function in minority youth with asthma in in the GALA II & SAGE II Studies. Am J Respir Crit Care Med. First published online 06 Jan 2016 as DOI: 10.1164/rccm.201508-1706OC