The effects of visceral fat accumulation by diabetes mellitus on bone metabolism

The number of obesity and diabetes mellitus in the world has been rapidly increasing in population. Current lifestyle initiates obesity, especially visceral fat accumulation, and leads to the onset of metabolic syndrome, such as cardiovascular events, hyperlipidemia and diabetes mellitus, based on insulin resistance. Several studies of adipocyte function have revealed that adipose tissue is not merely an energy-storing organ but it secretes a variety of biologically active molecules, conceptualized as "adipocytokines", including tumor necrosis factor-alpha, estrogen, leptin and adiponectin and that abnormal secretion of these adipocytokines causes metabolic syndrome. Adipocytes exist not only in the visceral and subcutaneous tissue but also in the bone marrow. Therefore, it is important to know their effects not only on glucose and lipid metabolism but also on bone metabolism. This report aims to review some of the effects of visceral fat accumulation by diabetes mellitus on bone metabolism.