Serum levels of osteocalcin are inversely associated with the metabolic syndrome and the severity of coronary artery disease in Chinese men

Objective Osteocalcin is a bone-derived protein and has been shown to play an important role in regulating glucose and fat metabolism. We therefore investigated the association of serum levels of osteocalcin with the metabolic syndrome (MS) and coronary atherosclerosis in Chinese men. Research design and methods Serum osteocalcin levels were measured by an electrochemiluminescence immunoassay in 181 men who underwent coronary angiography, and their association with the MS and the severity of coronary artery disease (CAD) were studied. Results Osteocalcin levels in patients with the MS were significantly lower compared with those in non-MS subjects (P < 0.001) and decreased correspondingly with the increasing number of components of the MS (P < 0.001). Multiple logistic regression analysis demonstrated that osteocalcin was independently associated with the MS (OR = 0.060, 95% CI: 0.005-0.651). In multiple stepwise regression analysis, waist circumference (P = 0.001) and fasting plasma glucose (P = 0.002) were independently associated with serum osteocalcin. Subgroup analysis in 60 subjects with normal glucose tolerance showed that serum osteocalcin decreased significantly in patients with CAD compared with those without CAD (P = 0.029) and decreased significantly as the number of stenotic vessels increased (P = 0.033). Furthermore, serum osteocalcin showed an independent correlation with coronary atherosclerosis index (standardized beta = -0.497, P = 0.003). Conclusion Serum osteocalcin is inversely associated with the MS as well as the severity of coronary atherosclerosis in Chinese men, supporting the new concept that bone has the reciprocal regulation with energy metabolism.