Context: Recent animal studies showed that osteocalcin action is related to not only bone metabolism but also glucose metabolism and fat mass. We investigated the relationship between two bone formation markers, serum osteocalcin and bone-specific alkaline phosphatase, and glucose metabolism, serum adiponectin, and the amount of fat mass as well as atherosclerosis parameters in men and postmenopausal women with type 2 diabetes.

Methods: A total of 179 men and 149 postmenopausal women were recruited consecutively, and radiographic and biochemical characteristics were collected. Brachial-ankle pulse wave velocity (baPWV) and intima-media thickness (IMT) were evaluated as the parameters of atherosclerosis.

Results: Multiple regression analysis adjusted for age, duration of diabetes, body mass index, and serum creatinine showed that osteocalcin negatively correlated with fasting plasma glucose and hemoglobin A_1c in both men and postmenopausal women (P < 0.05) and with percent fat, baPWV, and IMT in men (P < 0.05). Osteocalcin positively correlated with total adiponectin in postmenopausal women (P < 0.001). After additional adjustments for systolic blood pressure, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, hemoglobin A_1c, and Brinkmann index, osteocalcin still significantly and negatively correlated with baPWV and IMT in men. In contrast, osteocalcin did not correlate with fasting C-peptide, and bone-specific alkaline phosphatase did not correlate with any variable in either men or postmenopausal women.

Conclusions: Serum osteocalcin is associated with glucose and total adiponectin levels, fat mass, and atherosclerosis parameters in patients with type 2 diabetes, suggesting that osteocalcin is important for not only bone metabolism but also glucose and fat metabolism.