Serum osteocalcin levels are inversely associated with plasma glucose and body mass index in healthy Chinese women.

Aim: Osteocalcin, a biochemical marker of bone formation, has been suggested to be involved in the regulation of energy metabolism. The aim of this study was to investigate the possible association between serum osteocalcin and markers of glucose and lipid metabolism in a large sample of healthy Chinese women.

Methods: A total of 2032 healthy Chinese women in Shanghai, aged 20-94 (including 1396 discovery-study subjects and 636 postmenopausal women for a reduplication analysis) were recruited. Their serum osteocalcin, calcium and the relevant measurements were analyzed. A Spearman correlation analysis was performed between osteocalcin and the other markers of energy metabolism including triglyceride, total cholesterol, fasting plasma glucose (FPG), serum insulin, body mass index and homeostasis model assessment-insulin resistance. Separate multiple regression analyses were performed with data from the discovery and reduplication subjects to determine whether serum osteocalcin concentration was an independent predictor of the glucose or lipid metabolism markers.

Results: For the discovery-study subjects, serum osteocalcin was found to be negatively associated with weight (r=-0.08, P=0.002), BMI (-0.13, P<0.001) and FPG (r=-0.13, P=0.001). Similar results were also found in the reduplication subjects (weight: r=-0.19, P=0.016; BMI: r=-0.23, P=0.003; FPG: r=-0.28, P<0.001). In the multiple regression analysis, serum osteocalcin was revealed as a potential independent predictor for FPG (β=-0.07 and -0.210 for discovery and reduplication, respectively, P<0.01) and BMI (β=-0.127 and -0.299 for discovery and reduplication, respectively, P<0.01).

Conclusion: Serum osteocalcin is negatively associated with weight BMI and FPG in healthy Chinese women. Therefore, osteocalcin might contribute to obesity and diabetes.