Purpose: To investigate the changes of plasma 25(OH)D levels in type 2 diabetes mellitus (T2DM) patients and explore its role in the dysfunction of glucose and lipid metabolism and cognition.
Methods: One hundred and thirty-two T2DM patients were enrolled and the demographic and clinical data were collected. The plasma concentration of 25(OH)D was detected and the patients were divided into two groups including a Vitamin D insufficient (VDI) group and a normal VD group according to the clinical diagnostic criterial of VDI with the plasma 25(OH)D level less than 29 ng/mL.