Endocrine Abstracts

Introduction: Osteocalcin is a bone-specific hormone also involved in regulation of glucose and fat mass metabolism. It regulates energy expenditure by acting on adipocytes and pancreatic islet cells. The aim of the present study was to examine the relation between serum osteocalcin and glucose metabolism in young women with obesity.

Material and methods: A total of 66 healthy women were included in the analysis. Data on body mass index (BMI), waist circumference (WC), serum osteocalcin, fasting plasma glucose (FPG) and insulin levels were collected. Insulin sensitivity was estimated by homeostasis model assessment for insulin resistance (HOMA-IR = [glucose (mmol/l) × insulin (mIU/l)]) and by quantitative insulin sensitivity check index (QUICKI index = 1/[log (insulin in mIU/l) + log (glucose in mmol/l)]). All measurements were done in the morning after an 8-h overnight fast.

Results: The participants of the study were classified according to their weight status, 36 women with obesity (BMI ≥30 kg/m², WHO) and 30 normal weight women (BMI ≤ 25 kg/m²). The mean age was 33.1±5.9 years and was similar in both groups. Serum osteocalcin was significantly lower in women with obesity than in normal weight women (8.9±4.1 vs 13.8±6.9 ng/ml, P=0.009). Insulin resistance was detected by HOMA-IR in 55.5% and by the QUICKI index in 68.2% in women with obesity and no cases of insulin resistance in normal weight women. Serum osteocalcin was inversely associated with BMI (P=0.02), waist circumference (P=0.021), FPG (P=0.003) and fasting insulin (P=0.004). Moreover, osteocalcin was inversely associated to HOMA-IR (P=0.028) and QUICKI index (P=0.020).

Conclusion: These results suggests that serum osteocalcin concentration was significantly lower and inversely associated with blood markers of glucose metabolism, insulin secretion, insulin resistance and adiposity in young women with obesity.