Aging biomarkers: Potential mediators of association between long‐term ozone exposure and risk of atherosclerosis

Background Long‐term exposure to ambient ozone links to aging biomarkers and increased risk for atherosclerotic cardiovascular diseases (ASCVD). However, the roles of aging biomarkers in the association of long‐term exposure to ambient ozone with ASCVD are unclear. Methods A total of 5298 participants completed the questionnaire and physical examination and provided biological specimens. Aging biomarkers (telomere length [TL] and mitochondrial copy number [mtDNA‐CN]) were measured by using a real‐time polymerase chain reaction method. The concentration of ambient ozone was assessed using a random forest model. Associations of ambient ozone or aging biomarkers with 10‐year ASCVD risk were analyzed using logistic regression models. The roles of aging biomarkers in the association of ambient ozone exposure with 10‐year ASCVD risk were explored by mediation analysis. Results The adjusted odds ratios and 95% confidence interval of high 10‐year ASCVD risk were 1.16 (1.08, 1.25), 0.71 (0.60, 0.85), and 0.78 (0.64, 0.96) in association with each 1‐unit increment in ambient ozone (1 μg/m3) concentration, relative TL, and mtDNA‐CN, respectively. The mediated proportion of the association between ambient ozone exposure and high 10‐year ASCVD risk by TL or mtDNA‐CN was 21.13% or 7.75%, respectively. The total proportion of association between ambient ozone exposure and high 10‐year ASCVD risk mediated by TL plus mtDNA‐CN was 21.02%. Conclusions Long‐term exposure to ambient ozone was associated with increased 10‐year ASCVD risk, and the association was partially mediated by aging biomarkers (shortened TL and decreased mtDNA‐CN). This study indicated that ambient ozone pollution–related ASCVD risk might be partially explained by the telomere–mitochondrial axis of aging.