Long-term ambient ozone exposure and accelerated biological aging: A longitudinal analysis among middle-aged and older adults

BACKGROUND: Population aging and the escalating ozone (O₃) pollution are both global challenges. Yet the interplay between them, such as associations between long-term O₃ exposure and biological aging acceleration (BAA), remains poorly understood. METHODS: This study examined O₃-BAA associations among 5576 Chinese adults aged 45-80 years from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study (CHARLS). We calculated participants' BAA via the Klemera-Doubal method with 11 clinical biomarkers. The 12-month average ambient O₃ concentration before BAA assessment was determined. Change-to-change analyses with generalized linear models were conducted to regress changes in BAA against changes in O₃ exposure across two assessments from 2011 to 2015, by comparing each subject with her/himself. Fixed-effect analysis of repeated measures data was further used to examine the robustness of the O₃-BAA association. Subgroup analysis was performed to identify susceptible populations. RESULTS: The change-to-change analyses show that a 5 μg/m³ increment in O₃ exposure was associated with a 0.67-year (95% CI 0.37, 0.97) increment in BAA, and a 85% higher probability of increased BAA (odds ratio 1.85, 95% CI 1.36, 2.51). These effect estimates remained robust after adjusting for co-varying PM2.5 and NO₂. The fixed-effect models also identified a positive and significant O₃-BAA association. Older adults, females, rural residents, individuals with lower education, and those with existing chronic conditions were more susceptible to O₃ exposure. CONCLUSIONS: With increasing O₃ pollution globally, our findings highlight the urgency of mitigating O₃ pollution to promote healthy aging.