Circulating Osteocalcin is Associated with Time in range and other Metrics Assessed by Continuous Glucose Monitoring in Type 2 Diabetes

Abstract Background:Osteocalcin is a sort of protein secreted by osteoblast exclusively，and new observations have verified that glucose balance can be modulated by it in some ways. TIR has attracted more and more attention as an emerging blood glucose evaluation index. In this study, the association between TIR and the level of circulating osteocalcin was investigated in type 2 diabetes.METHODS376 patients with type 2 diabetes were enrolled in our trail, all of them performed three consecutive days of monitoring. And they were divided into four groups on account of the quartile of osteocalcin. TIR, Time below range(TBR）, Time above range(TAR) and measures of glycemic variability (GV) were assessed for analysing. After a 100g standard steamed bread meal, blood glucose (Glu0h Glu0.5h, Glu1h, Glu2h, GLu3h), C-peptide (Cp0h, Cp0.5h, Cp1h, Cp2h, Cp3h), serum insulin (INS0h, INS0.5h, INS1h, INS2h, INS3h) concentrations at different time points were obtained. HOMA-IS, HOMA-β was calculated to evaluate insulin sensitivity and insulin secreting of the participants.RESULTSTIR increased significantly as the osteocalcin level increased between groups (p < 0.05). No significant differences were found in gender composition, age, weight, BMI, diabetes duration, K+, Ca+, Creatinine, blood pressure among groups (respectively, p>0.05). Osteocalcin had positive correlation with TIR (r=0.227, P<0.001), while a negative correlation was presented in osteocalcin and TAR (-0.229, P< 0.001). Likewise, osteocalcin was negatively correlated with INS0h, INS0.5h, fasting blood glucose and postprandial blood glucose at any time point after intaking of a standard meal.Meanwhile, osteocalcin had a negative correlation with the majority of GV indexes including standard deviation (SD), mean blood glouse (MBG), mean of daily differences (MODD), average daily danger range (ADDR). Multiple stepwise regression analysis demonstrated that osteocalcin was an independent contributor of TIR, TAR, and HOMA-IS.CONCLUSIONSCirculating osteocalcin has a positive correlation with TIR, and is an protective factor of TIR and insulin sensitivity in type 2 diabetic patients.