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Air pollution and telomere length: interaction by steroid use?

Published online: June 24, 2019

Telomere length (TL) can serve as a potential biomarker for conditions associated with chronic oxidative stress and inflammation such as asthma. Exposure to ambient air pollution is a possible risk factor for telomere shortening. Previous studies of telomere length and exposure to air pollution have demonstrated that shorter telomeres were associated with increasing levels of air pollution. Telomeric DNA damage may have adverse impacts in children and adolescents due to their physical and immune system development. Currently, there are two published studies on exposure to outdoor air pollution and TL in children.

In an Original Article recently published in The Journal of Allergy & Clinical Immunology (JACI), Lee and colleagues hypothesized that exposure to ambient air pollutants is associated with shorter telomere length in African American children and adolescents. Furthermore, the authors examined whether the association varies with African genetic ancestry, asthma status and steroid medication use. They used a subset of participants (n=1,072) from the Study of African Americans, Asthma, Genes & Environment (SAGE), a case-control study of asthma among African American children and adolescents (ages 8-21) from the San Francisco Bay Area.

Linear regression was used to examine associations between absolute telomere length and the estimated annual average residential ozone (O3) and fine particulate matter (PM2.5) exposures in a cross-sectional analysis. African ancestry, asthma status and the use of steroid medications were examined as potential effect modifiers by adding interaction terms to the regression models and conducting subgroup analyses.

Lee et al. found that exposure to ambient air pollution among African Americans during childhood and adolescence may increase the risk of telomere shortening. A unit increase in African ancestry was significantly associated with longer telomeres. The effects of air pollution on telomere length did not vary significantly by African ancestry and asthma status. However, the authors discovered that the use of inhaled or oral steroids for asthma therapy was an important effect modifier. Steroid therapy appeared to reduce the harmful effects of air pollution on telomere length among children with asthma.

The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.