PLASMA TOTAL OSTEOCALCIN LEVELS IN TYPE 2 DIABETICS ATTENDING THE LAGOS UNIVERSITY TEACHING HOSPITAL

Abstract

Background: Osteocalcin is a biochemical marker of bone formation but recent animal and in vitro cell studies suggest a role for it in glucose and energy metabolism. This study was carried out to determine the relationship of plasma osteocalcin to glycaemic control and measures of obesity in patients with type 2 diabetes.
Method: A cross-sectional study was performed of patients with type 2 diabetes attending the Lagos University Teaching Hospital. Body mass index (BMI), waist circumference (WC), plasma osteocalcin, fasting plasma glucose and glycated haemoglobin (HbA1c) were determined. The Mann-Whitney U test was employed to compare the levels of osteocalcin in the diabetics to the non- diabetic participants. Relationship was tested with the Spearman’s correlation coefficient and multiple stepwise regression analyses. p value ≤ 0.05 was considered to be statistically significant.
Results: A total of 213 subjects (109 females, 104 males) participated in this study (108 diabetics, 105 non-diabetic controls). Significantly higher levels of osteocalcin were observed in the controls compared to the diabetics (p=0.002). Plasma osteocalcin had significant inverse relationships with HbA1c, BMI, WC and WHR (p<0.001, p<0.001, p<0.001 and p=0.020 respectively). There was no significant relationship of osteocalcin with fasting plasma glucose (p=0.066).
Conclusion: Lower levels of plasma osteocalcin have been demonstrated in patients with type 2 diabetes. These levels were observed to be inversely correlated to glycaemic control and anthropometric measures of obesity in these patients. The findings from this study may suggest an endocrine role for osteocalcin in glucose and energy metabolism.