Association Between Circulating Osteocalcin And Glucose Homoeostasis In Adults With Type 1 Diabetes

OBJECTIVE:To investigate the level of osteocalcin in adult type 1 diabetes mellitus(T1DM)and its role in the glycemic metabolism.Methods:This retrospective study comprised 105 T1DM patients and 92 non-diabetic patients who were hospitalized in Drum Tower Hospital Affiliated to Nanjing University Medical School during January 1,2015 to January 1,2017.The Gender,age,height.weight,and duration of diabetes were collected.BMI was calculates from body weight and body size as body weight(kilograms)/height(metres2).Blood samples were drawn between 8:00 and 10:00 a.m.after an overnight fast.The following laboratory parameters were measured:150 grams steamed bread meal test two-point blood glucose(FBG,2h-BG),two-point blood C-peptide(Fasting C peptide and two hours postprandial C peptide),glycosylated hemoglobin(HbAlc),and triglyceride,total cholesterol,high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C),apolipoprotein A1(apoAl),apolipoprotein B(apoB),serum osteocalcin,procollagen type 1 N-terminal propeptide(P1NP),β-C-terminal telopeptide of type I collagen(β-CTX),serum alkaline phosphatase(ALP),serum calcium,serum phosphorus,serum 25 hydroxy-vitamin D3,serum calcitonin,serum parathyroid hormone(PTH).Analysis of the relationship between osteocalcin and glucose metabolism in adult T1DM.Results:The level of osteocalcin was significantly lower in T1DM(P<0.05).Besides,osteocalcin was proved to be inversely related to glycosylated hemoglobin(HbA1c)(r=-0.262,P=0.002),but positively related to serum alkaline phosphatase(ALP)(r=0.222,P=0.006),serum phosphorus(r=0.178,P=0.029),serum parathyroid hormone(PTH)(r=0.361,P=0.001),P-C-terminal telopeptide of type I collagen(β-CTX)(r=0.584,P=0.000)and procollagen type 1 N-terminal propeptide(P1NP)(r=0.817,P=0.000).Multivariate regression analysis revealed that osteocalcin was an independent risk factor for HbA1c(P=0.024)in adult T1DM,after the adjustment of age,sex,and BMI.For every 1 ng/ml increase of osteocalcin,HbA1c decreases by 0.18%.TIDM with higher osteocalcin showed significantly lower HbAlc(P<0.05),but significantly higher levels of fasting C peptide,β-CTX and P1NP(P<0.05).Conclusion:The level of osteocalcin was significantly decreased in T1DM.Nevertheless,higher osteocalcin in T1DM was associated with better glycemia and islet function,indicating the involvement of osteocalcin in the regulation of glycemic metabolism in T1DM.