Biochemical indicators of bone metabolism may change at the initial stage of type 2 diabetes, and the risk of osteoporosis and fracture in patients is significantly increased compared with normal people. Osteoporosis is a systemic bone disease characterized by low bone mass and degeneration of bone tissue microstructure, leading to increased bone fragility and susceptibility to fractures. The main mechanism of type 2 diabetes is insulin resistance (IR). A large number of clinical studies have shown that there is a relationship between insulin resistance and osteoporosis. There is a close association between miR-155 in microRNAs (miRNAs) and IR. At present, studies have found that the increased expression of miR-155 can improve insulin sensitivity, and IR is a potential mechanism leading to diabetes induced osteoporosis. However, although the risk of osteoporosis or fracture in type 2 diabetes patients increases, their bone mineral density (BMD) values are still normal or even slightly increased. Therefore, at present, the relevant mechanism of osteoporosis fracture in type 2 diabetes cannot be fully explained by BMD alone. This article mainly reviews the progress of the relationship between miR-155 and osteoporosis in type 2 diabetes patients.

Vitamin D can regulate calcium and phosphorus metabolism and maintain bone health. In recent years, more and more studies have shown that vitamin D and its receptors have the potential to protect diabetic nephropathy. Animal studies and clinical trials have shown the correlation between vitamin D levels and the risk of diabetic nephropathy. Supplementation of vitamin D or its analogs can improve endothelial cell damage, reduce inflammation, proteinuria, and renal fibrosis and thus delay the process of diabetic nephropathy. Therefore, vitamin D and its receptor are expected to become a new choice for the prevention and treatment of diabetic nephropathy. This review summarizes the new research progress of vitamin D on the protective mechanism of diabetic nephropathy.