The area under the curve (AUC) of 25-hydroxy-vitamin D, PTH, BGP, β-CTX, T-PINP and ultrasound BMD were 0.910, 0.826, 0.841, 0.822, 0.821, 0.811 respectively in the diagnosis of early diabetic nephropathy, and the AUC of combined diagnosis was 0.995. This evidence concerns the gene CYP27A1 and diabetic kidney disease.