GPT and type 2 diabetes mellitus: DM: diabetic; NDM: non-diabetic; T2DM: type 2 diabetes mellitus; ALT: alanine aminotransferase; HDL-C: high-density lipoprotein cholesterol; LDL-C: low-density lipoprotein cholesterol; CRP: C-reactive protein; VDBP: vitamin D binding protein.