Relationships among Bone Metabolic Markers, Body Fat Composition and Carotid Intima–Media Thickness in Premenopausal Obese Women

Osteocalcin (OC) is inversely related to body fat distribution and fasting glucose levels. We sought to observe the effect of OC on fat distribution and subclinical atherosclerosis as measured by carotid intima-media thickness (CIMT) in premenopausal obese women. In this prospective observational study, totally, 73 premenopausal obese women (aged 17-55 years) and 53 healthy women (aged 20-50 years) with normal weight were included as controls. Anthropometric measurements, total fat and fat ratio, insulin, fasting blood glucose, and OC levels were estimated. Ultrasonography was used to assess fat distribution, and fat thickness was measured in 4 regions. Subcutaneous fat (SCF), visceral fat (VF), and preperitoneal fat (PPF) thicknesses were considerably higher in obese subjects (p<0.01) than healthy controls, while OC levels were significantly lower. No correlation was observed between OC levels and SCF, VF, or PPF. In a multiple regression analysis, OC was significantly positively associated with SCF (p=0.04, Beta=0.284). No associations were observed between OC levels and VF, PPF, or CIMT. A significant association was observed between parathyroid hormone (PTH) and VF (p=0.021, Beta=0.284), and vitamin D levels were inversely associated with VF (p=0.002, r=−0.366). OC levels were lower in premenopausal obese women than normal-weight healthy controls, but OC exhibited no correlation with VF or PPF, and only a weak positive association with SCF. Additionally, VF was positively correlated with PTH and inversely correlated with vitamin D. These results suggest that OC may be an early indicator of lipid accumulation in te subcutaneous area and development of atherosclerosis.