Abstract
<title>Abstract</title> <p> <bold>Objective</bold> To investigate the relationships of individual and combined urinary metal exposure with liver function biomarkers and to determine whether these associations differed by region. <bold>Methods</bold> This cross-sectional study included 284 adults aged ≥ 60 years residing in an industrial non-ferrous smelting region and a nearby upwind non-industrial region in Northwest China. Urinary concentrations of 14 metals were quantified using ICP-MS and adjusted for creatinine. Associations of individual metals with liver function biomarkers and potential dose–response patterns were examined using multivariable linear regression and restricted cubic spline models. Bayesian kernel machine regression (BKMR) and quantile g-computation were subsequently applied to evaluate the effects of metal mixtures. <bold>Results</bold> Higher urinary Cu and Zn were associated with increased ALT, while Li and As were associated with increased AST. Ni was inversely associated with the AST/ALT ratio. BKMR indicated Zn and Hg contributed most to ALT, and Ni and Cr to the AST/ALT ratio. QG-comp showed no significant overall mixture effect. Stronger associations were observed in the non-industrial region. <bold>Conclusion</bold> Urinary metals were associated with liver biomarkers, with heterogeneous mixture effects and regional differences. </p>