Relationship between plasma osteocalcin, glycaemic control and components of metabolic syndrome in adult Nigerians with type 2 diabetes mellitus

Aims: To determine the levels of plasma osteocalcin (OC) in Nigerians with type 2 diabetes mellitus (DM) and compare these to levels in non-diabetic controls (NDM). To assess the relationship of OC to glycaemic control and parameters of metabolic syndrome (MetS) and compare its levels in Nigerians with and without MetS. Methods: The waist circumference (WC), body mass index (BMI) and blood pressure of 200 study participants were taken. Plasma osteocalcin, fasting glucose (FPG), glycated haemoglobin (HbA1c), high density lipoprotein cholesterol (HDL-c) and triglyceride (TG) levels were determined. Metabolic syndrome was defined by the International Diabetes Federation criteria. Statistical significance was set at 0.05. Results: Osteocalcin levels were lower in the DM group (p = 0.002) and inversely related to FPG (r = - 0.198, p = 0.003), HbA1c (r = - 0.313, p < 0.001), BMI (r = - 0.331, p < 0.001), WC (r = - 0.339, p < 0.001) and TG (r = - 0.145, p = 0.040), but directly related to HDL-c levels (r = 0.166, p = 0.019). Osteocalcin was higher in participants without MetS (Median 8.75 ng/mL IQR[5.48-12.68] ng/mL) than in those with MetS (Median 4.74 ng/Ml, IQR[2.80-9.12] ng/mL), p < 0.001. Conclusions: Plasma osteocalcin levels are inversely associated with good glycaemic control and components of MetS and are lower in individuals with DM and in those with MetS. These findings support a vital role of the bone, in the regulation of glucose and energy metabolism, in Nigerians. Further extensive studies are required to explore the potentials of OC in the management of DM and MetS. (C) 2016 Diabetes India. Published by Elsevier Ltd. All rights reserved.