Background: Insulin is the key link between energy and bone metabolism. In the presence of insulin osteoblasts secrete undercarboxylated osteocalcin, which promotes pancreatic beta-cell proliferation, insulin secretion and its tissue sensitivity, fatty tissue metabolism and energy expenditure thus contributing to euglycemia. The aim was to investigate osteocalcin and undercarboxylated osteocalcin in adult patients with newly diagnosed diabetes mellitus type 2 (DM2) advised on lifestyle changes for glycemic optimisation.
Methods: Study included 57 patients newly diagnosed with DM2 (21 F, 36 M; median, range; age 57 years, 30-80; BMI 29.2, 23.2-43.6; blood glucose 9.5 nmol/L, 7.9-15; HbA1c 8.0%, 6.3-12.0). Patients were advised on life-style improvement, no blood glucose medication was prescribed, and re-evaluated after three months. Osteocalcin, undercarboxylated osteocalcin and crosslaps were measured by commercial kits, and other biochemical parameters by standard recommended methods.
Results: No difference for analysed data existed between sexes. At second visit (n=22) lifestyle changes were observed by statistically significant decrease of BMI, glucose, HbA1c and indices of steady state beta-cell function. No difference for osteocalcin or undercarboxylated osteocalcin was found between visits. For the second visit (n=22) two pairs of parameters revealed statistically significant negative correlations between glucose and osteocalcin (p=0.01), and also glucose and crosslaps (p=0.046), considered unexpected.
Conclusions: Changes of osteocalcin and undercarboxylated osteocalcin with improvement of gylcemia were not found after three months, although optimization of HbA1c goal (≤ 6.5%) was achieved solely by lifestyle advice. At the second visit interesting negative correlations of glucose with osteocalcin and also crosslaps as glycemic optimisation were observed. This might indicate the association of glucose and bone metabolism. Corresponding relationship of crosslaps and glucose reflects coupling of bone turnover actions, as both osteocalcin and crosslaps correlated with glucose in a positive fashion.
Disclosure: The authors declared no competing interests. This work was supported by Croatian Ministry of Science, Education and Sport, project no 214-1080229-0163 (2007-2013).