Low Serum Osteocalcin Level as a Risk Factor for Metabolic Syndrome in Korean Men: A Retrospective Longitudinal Study

Abstract

Background: Recent studies have suggested that low serum osteocalcin levels are associated with metabolic syndrome (MetS). However, the association between serum osteocalcin levels and the incidence of MetS remains unclear. This aim of this study was to investigate the relationship between serum osteocalcin levels and MetS development in Korean men.Methods: This retrospective study included 2,837 Korean men who were not diagnosed with MetS and recruited from the Health Promotion Center from January 2003 through December 2018. They were followed up at the center until the participant was newly diagnosed with MetS or until the last follow-up visit if the participant was not diagnosed with MetS. Serum osteocalcin levels were measured using an electrochemiluminescence immunoassay. The participants were divided into quartiles (Q1–Q4) based on their serum osteocalcin levels. Cox proportional hazard models were used to test the independent association of serum osteocalcin levels with the development of MetS, and hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.Results: In the baseline analysis, blood pressure, body mass index, waist circumference, waist-hip ratio, body fat mass, fasting glucose, hemoglobin A1c (P for trend < 0.001 for all), total cholesterol (P for trend = 0.026), triglyceride (P for trend = 0.003), and low-density lipoprotein cholesterol (P for trend = 0.031) varied inversely with the osteocalcin quartile. In addition, the prevalence of abdominal obesity (P for trend = 0.001), high blood pressure (P for trend = 0.008), and hyperglycemia (P for trend < 0.001) decreased as the osteocalcin quartile increased. After a mean follow-up time of 2.76 years, MetS occurred in 518 participants (18.26%), and baseline serum osteocalcin levels were found to be inversely associated with the incident risk of MetS (P for trend < 0.001 across quartiles of osteocalcin levels). In a fully adjusted model, HR for MetS in the first quartile (the lowest osteocalcin concentration) was significantly higher than that for MetS in the fourth quartile (HR, 1.40; 95% CI, 1.06–1.84).Conclusion: Low serum osteocalcin levels at baseline were associated with unfavorable metabolic profiles and a higher risk of incident MetS in Korean men.