Independent Relationship between Serum Osteocalcin and Uric Acid in a Cohort of Apparently Healthy Obese Subjects

Background: It is generally accepted that serum osteocalcin (OC) is a reliable marker of bone formation, while the role of serum uric acid (UA) in bone metabolism is still debated. However, recent studies have shown that endogenous UA within the normal range may exert a positive effect in bone formation by means of its antioxidant role in both sexes. To date, no studies have been carried out in obese subjects aiming to study the relationship between serum OC and UA, given that obesity is considered as a risk factor for osteoporosis and fracture and, at the same time, for cardiovascular events. Objectives: Our search purpose was to verify the relationship between endogenous levels of OC and serum UA in a cohort of obese subjects without any metabolic or chronic diseases (i.e. hypertension, renal failure, diabetes mellitus, etc.). Materials and Methods: One hundred and twenty one obese subjects (93 women and 28 men) were enrolled for this study. Serum OC and UA were assessed and compared with demographic characteristics, clinical and biochemical parameters (age, body mass index (BMI), blood pressure, waist circumference, serum lipids and glycaemia). Results: Serum OC was directly and independently correlated with circulating UA in our population of obese subjects, while neither BMI, age, serum lipids, fasting glycaemia nor gender showed a statistically significant correlation with endogenous plasma levels of OC. Conclusion: The positive effect determined by serum OC in bone metabolism of our obese subjects might be partly due to the antioxidant properties that normal plasma UA levels exert at bone tissue level.