Long-term exposure to air pollution, proteomic aging clocks, and liver-related outcomes in Chinese adults

Although air pollution is recognized as a contributor to accelerated biological aging, its associations with clinically significant liver-related outcomes and the potential role of proteomic aging remain unclear. We aimed to evaluate the associations of key air pollutants with liver-related outcomes and the potential mediating role of proteomic aging clocks. Among 504,006 China Kadoorie Biobank participants without liver disease or cancer, we used time-varying Cox regression to assess associations of PM_2.5, PM₁₀, NO₂, and warm-season O₃, and their mixtures with liver-related events (LRE) and liver-related mortality (LRM), and mediation analyses to examine the role of proteomic aging clocks (i.e., ProtAge). Long-term exposure to PM_2.5, PM₁₀, NO₂, and warm-season O₃ showed significant positive associations with LRE, while PM_2.5, PM₁₀, and NO₂ were also positively associated with LRM. A 1-unit increment in the weighted pollutant score was associated with an 81% higher risk of LRE (hazard ratio [HR] = 1.81 [1.65-1.98]) and a 17% higher risk of LRM (HR = 1.17 [1.05-1.31]). Acceleration in ProtAge was associated with higher risks of LRE (HR = 1.86 [1.16-2.97]) and LRM (HR = 4.43 [3.02-6.50]). ProtAge accounted for an estimated 7.1% and 12.5% of the associations of pollutant mixtures with LRE and LRM, respectively. Among proteins in ProtAge, CD248, GDF15, TNFRSF6B, and XG showed concordant associations in pollutant mixture-protein and protein-LRE analyses. Long-term air pollution was associated with higher risks of clinically significant liver-related outcomes. These findings suggest a possible role of proteomic aging in the association between air pollution and liver-related outcomes, warranting further investigation.