Combined effects of ambient air pollution exposure and biological aging on incident liver diseases: a large prospective cohort study

Both ambient air pollution exposure and biological aging are associated with incident liver diseases, but previous studies mainly focused on single-factor associations. This study aimed to assess the combined effects of air pollutant exposure and biological aging on liver diseases incidence and investigate the potential mediating role of biological aging. We analyzed 418 576 UK Biobank participants. Annual mean concentrations of PM2.5, PM10, PM2.5-10, NO2, and NO in 2010 were used to generate a weighted air pollution score. Biological ages were assessed using the Klemera-Doubal method biological age (KDM-BA) and phenotypic age (PhenoAge). Cox regression models and quantile g-computation were used to evaluate associations and joint effects. Mediation analyses explored the role of biological aging. Over a median follow-up of 13.57 years, 7991 (1.91%) participants developed liver diseases. Exposure to all pollutants and biological aging were associated with higher liver diseases risk. And NO2 contributed 42.31% to the mixture effect. Participants with higher levels of air pollutant exposure and biologically older status had a higher risk. Furthermore, the mediated proportion of accelerated biological aging was 1.9% to 7.7% for air pollution-associated liver diseases. Ambient air pollution exposure may increase liver diseases risk, with biological aging potentially involved in the mechanisms.