Low osteocalcin level is a risk factor for impaired glucose metabolism in a Chinese male population

AIMS/INTRODUCTION This study was to assess the association between serum osteocalcin level and glucose metabolism in a Chinese male population. MATERIALS AND METHODS We carried out a cross-sectional study with a cohort of participants from the Fangchenggang Area Male Health and Examination Survey. The cross-sectional study was carried out among 2,353 men, including 2,139 participants with normal glucose tolerance, 148 with impaired fasting glucose and 66 with type 2 diabetes. A subsample of 1,109 men with measurement of osteocalcin was observed in the cohort. After a 4-year follow-up period, 1,049 non-diabetic and 983 participants with normal glucose tolerance who submitted the available information were enrolled in the cohort. Participants were divided into group-H (≥23.33 ng/mL) and group-L (<23.33 ng/mL) by osteocalcin level. RESULTS In the cross-sectional study, osteocalcin levels were highest in participants with normal glucose tolerance, followed by those with impaired fasting glucose and type 2 diabetes (P < 0.001). In partial correlation analysis adjusted for age, serum osteocalcin level was related to glucose level (r = -0.082, P < 0.001), insulin level (r = -0.079, P < 0.001) and insulin resistance (r = -0.065, P = 0.002). Compared with group-H, group-L was associated with an increased risk of type 2 diabetes (odds ratio 2.107, 95% confidence interval 1.123-3.955), impaired fasting glucose (odds ratio 2.106; 95% CI 1.528-2.902), and insulin resistance (odds ratio 1.359, 95% confidence interval 1.080-1.710) adjusted for age, education levels, cigarette smoking and lipid profiles. In the cohort study, the increased risk of impaired fasting glucose was significant in group-L vs group-H (3.3% vs 1.2%, P = 0.026). CONCLUSIONS Low serum osteocalcin level was a risk factor for impaired glucose metabolism and subsequent type 2 diabetes.