TNF and type 2 diabetes mellitus: Among the mechanisms proposed to explain the association between T2DM and bone metabolism, the abnormal accumulation of visceral fat can increase the secretion of adipokines and inflammatory factors such as leptin, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) (7, 8), which may increase bone resorption and decrease bone mineral density (BMD) (9, 10).