Effect of exposure to traffic-related air pollution on liver function during the compensation period for cirrhosis: a 4-year follow-up cohort study

The increasing number of motor vehicles due to economic and urbanization development has raised concerns about the impact of traffic-related air pollution on human health. Research on the impact of traffic-related pollution on populations, particularly in individuals with liver cirrhosis, is currently lacking. In this study, we utilized data from compensated cirrhosis patients at the Second People’s Hospital in Tianjin, China, to investigate the effects of traffic-related air pollution exposure on liver function-related blood indicators. A multiple linear regression model was applied to analyze the exposure to six air pollutants as well as the proximity of patients’ residential (or work) addresses to traffic arteries (main roads, secondary roads, highways). The results indicated a significant correlation between traffic-related air pollution and certain levels of liver function. Specifically, PM2.5 exposure was positively correlated with prothrombin time [PT, P < 0.05, 95%CI = (0.119, 0.424)] and international normalized ratio [INR, P < 0.05, 95%CI = (0.003, 0.041)]; SO2 exposure was positively correlated with cholesterol [CHO, P < 0.05, 95%CI = (0.126, 0.947)]; CO exposure was positively correlated with cholinesterase [CHE, P < 0.05, 95%CI = (15,276.644, 55,907.446)], triglyceride [TG, P < 0.05, 95%CI = (0.741, 7.215)], and hemoglobin [Hb, P < 0.05, 95%CI = (26.211, 305.697)]; O3 exposure was positively correlated with creatine kinase [CK, P < 0.05, 95%CI = (0.012, 0.126)], CHO [P < 0.05, 95%CI = (0.008, 0.248)], and INR [P < 0.05, 95%CI = (0.001, 0.02)]; the distance to main roads was negatively correlated with aspartate aminotransferase [AST, P < 0.05, 95%CI = (-0.041, -0.001)], gamma-glutamyl transferase [GGT, P < 0.05, 95%CI = (-0.041, -0.001)], and serum ferritin [SF, P < 0.05, 95%CI = (-0.348, -0.062)]; and the distance to secondary roads was negatively correlated with PT [P < 0.05, 95%CI = (-0.007, -0.001)]. High-intensity traffic-related air pollution was found to have a negative influence on liver function, potentially causing liver damage. This research provides evidence of the detrimental effects of traffic-related air pollution on the liver.