Glycemic control and bone turnover in diabetes

There is a moderately decreased bone mass and low rate of bone turnover in patients with diabetes. However, the etiology of this remains unclear. To address this question, we examined whether glycémie control, as measured by blood glucose and glycosylated hemoglobin (HbA1c), influenced markers of bone turnover in 12 patients with diabetes and compared them to 6 healthy subjects. Fasting blood and urine samples were taken twice, at two months apart, with at least one sample taken when patients were in good control. Urinary excretion of pyridinium cross-links (PYD and DPD), markers of bone résorption, were analyzed by HPLC and normalized for creatinine. Serum levels of osteocalcin (OC), a marker of bone formation, were determined by standard radioimmunoassay. In the nine diabetic patients with an elevated blood glucose (ISO-330 mg/dl), mean PYD and OC were 9.4±4.3 nmol/mmol and 3.4±1.4 tig/ml, respectively, which were significantly decreased compared to healthy subjects, 14.6 ±5.7 nmol/mmol and 6.6 ±2.4 ng/ml, respectively (p<0.05). An inverse correlation was observed between blood glucose and markers of bone turnover (urinary PYDX and serum OC, rO.50, pO.Ol). Although HbAlc correlated inversely with serum OC (r-0.48, p<0.05), a relationship was not observed with markers of résorption. These data suggest that hyperglycemia is related to a low rate of bone turnover, and that poor glycémie control may be one factor influencing bone mass in patients with diabetes. (NJAES #0153866).