Air pollution associate with advanced hepatic fibrosis among patients with chronic liver disease

We aimed to investigate the association between air pollution and advanced fibrosis among patients with metabolic associated fatty liver disease (MAFLD) and chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. A total of 1376 participants who were seropositive for HBV surface antigen (HBsAg) or antibodies to HCV (anti-HCV) or had abnormal liver function in a community screening program from 2019 to 2021 were enrolled for the assessment of liver fibrosis using transient elastography. Daily estimates of air pollutants (particulate matter ≤2.5 microm in diameter [PM_2.5 ], nitrogen dioxide [NO₂ ], ozone [O₃ ] and benzene) were aggregated into mean estimates for the previous year based on the date of enrolment. Of the 1376 participants, 767 (52.8%) and 187 (13.6) had MAFLD and advanced fibrosis, respectively. A logistic regression analysis revealed that the factors associated with advanced liver fibrosis were HCV viremia (odds ratio [OR], 3.13; 95% confidence interval [CI], 2.05-4.77; p < 0.001), smoking (OR, 1.79; 95% CI, 1.16-2.74; p = 0.01), age (OR, 1.04; 95% CI, 1.02-1.05; p < 0.001) and PM_2.5 (OR, 1.10; 95% CI, 1.05-1.16; p < 0.001). Linear regression analysis revealed that LSM was independently correlated with PM_2.5 (β: 0.134; 95% CI: 0.025, 0.243; p = 0.02). There was a dose-dependent relationship between different fibrotic stages and the PM_2.5 level (the PM_2.5 level in patients with fibrotic stages 0, 1-2 and 3-4: 27.9, 28.4, and 29.3 microg/m³ , respectively; trend p < 0.001). Exposure to PM_2.5 , as well as HBV and HCV infections, is associated with advanced liver fibrosis in patients with MAFLD. There was a dose-dependent correlation between PM_2.5 levels and the severity of hepatic fibrosis.