GPT and diabetes mellitus: In the present study, we found that an increase of each unit of the AST/ALT ratio reduced the risk of prediabetes by 21% (HR:0.79, 95%CI: 0.75-0.84 P<0.0001) after adjusting for gender, age, DBP, SBP, BMI, HDL-C, TG, LDL-C, TC, Scr, FPG, BUN, drinking status, smoking status and family history of diabetes.