[Bone metabolic markers and osteoporosis associated with diabetes mellitus]

Diabetes mellitus has been documented to affect bone and calcium metabolism. However, there is conflicting data on the frequency of fractures, changes of bone mineral density and the levels of bone metabolic markers in diabetes. These results may be related to heterogeneity of the patients in the studies, i.e., the presence or absence of insulin injection, body mass index, the amounts of intrinsic insulin secretion and/or insulin resistance. The combination of poor bone quality and frequent injurious falls would be expected to increase fracture incidence and a recent report revealed that older women with diabetes had a particularly increased risk of fractures. The metabolic effects of poor glycemic control lead to increased bone resorption without sufficient bone formation. With respect to bone metabolic markers, decreased levels of osteocalcin (OC) have been commonly reported. It is not known whether decreased OC is a predictive factor for fractures in diabetes, but the osteocalcin levels have been found to return toward the normal range after glycemic control. Since OC is known to be glycosylated, it is also possible that the measurement would be affected by high glucose conditions. The exact value of bone metabolic markers in diabetes has not been established, but measurement of osteocalcin may be a useful tool for evaluation of risk of fractures in diabetic patients.