When analyzed by quartiles, the highest quartile (Q4) of the ALT/AST ratio demonstrated a nearly threefold increase in diabetes risk compared to the lowest quartile (Q1) (HR = 2.94; 95% CI: 2.42–3.57, P < 0.001), with a clear and strong dose-response trend (P for trend < 0.001). This evidence concerns the gene GPT and diabetes mellitus.