J Allergy Clin Immunol

Background:Telomere length (TL) can serve as a potential biomarker for conditions associated with chronic oxidative stress and inflammation, such as asthma. Air pollution can induce oxidative stress. Understanding the relationship between TL, asthma, and air pollution is important for identifying risk factors contributing to unhealthy aging in children. Objectives: We sought to investigate associations between exposures to ambient air pollutants and TL in African American children and adolescents and to examine whether African ancestry, asthma status, and steroid medication use alter the association.Methods:Linear regression was used to examine associations between absolute telomere length (aTL) and estimated annual average residential ozone (O3) and fine particulate matter with a diameter of 2.5 \u3bcm or less (PM2.5) exposures in a cross-sectional analysis of 1072 children in an existing asthma case-control study. African ancestry, asthma status, and use of steroid medications were examined as effect modifiers.Results:Participants\u2019 aTLs were measured by using quantitative PCR. A 1-ppb and 1 \u3bcg/m3 increase in annual average exposure to O3 and PM2.5 were associated with a decrease in aTL of 37.1 kilo-base pair (kb; 95% CI, 1266.7 to 127.4 kb) and 57.1 kb (95% CI, 12118.1 to 3.9 kb), respectively. African ancestry and asthma were not effect modifiers; however, exposure to steroid medications modified the relationships between TL and pollutants. Past-year exposure to O3 and PM2.5 was associated with shorter TLs in patients without steroid use.Conclusion:Exposure to air pollution was associated with shorter TLs in nonasthmatic children and adolescents. This was not the case for asthmatic children as a group, but those receiving steroid medication had less shortening than those not using steroids. Reduced exposure to air pollution in childhood might help to preserve TL.20192020-09-01T00:00:00ZR01 HL141992/HL/NHLBI NIH HHS/United StatesK01 HL140218/HL/NHLBI NIH HHS/United StatesT32 HG000044/HG/NHGRI NIH HHS/United StatesR01 HL117004/HL/NHLBI NIH HHS/United StatesR21 ES024844/ES/NIEHS NIH HHS/United StatesR01 HL135156/HL/NHLBI NIH HHS/United StatesT32 GM007546/GM/NIGMS NIH HHS/United StatesRL5 GM118984/GM/NIGMS NIH HHS/United StatesR01 MD010443/MD/NIMHD NIH HHS/United States31247265PMC6938647828