[Calcium homeostasis and osteoporosis in diabetes mellitus and the metabolic syndrome].

Hyperglycemia and increase in advanced glycation end products in patients with diabetes are known to cause impaired calcium homeostasis such as reduction in parathyroid hormone secretion, decrease in calcium (Ca) absorption resulting from impaired vitamin D action, increase in urinary Ca excretion, impaired osteoblastic function, and deterioration of bone quality. On the other hand, fat deposition accompanied by the metabolic syndrome are positively linked to increased bone mineral density (BMD) and reduced fracture risk through increased body weight. However, body fat has a detrimental effect on BMD after adjustment for weight, and gives less mechanical stress on bone than muscle tissue that is firmly attached to bone via the tendon. Thus, converting fat into muscle tissue by regular exercise and healthy diet helps not only prevent hyperglycemia but also osteoporosis.