Clinical and Body Compositional Factors Associated with Metabolic Syndrome in Obese Koreans: A Cross-Sectional Study

Background: Obesity and metabolic syndrome (MetS) are increasing rapidly worldwide, but metabolically healthy population exists. Thus, this study evaluated the proportion of obesity and MetS and investigated clinical and body compositional factors associated with MetS in obese Koreans. Methods: This cross-sectional observational study enrolled subjects from the Korea National Health and Nutrition Examination Survey (n=15,408). Obesity was defined by body mass index (BMI) cutoff points of 25 and 27.5kg/m(2). Clinical and laboratory parameters were compared by MetS presence and factors associated with insulin resistance or MetS in obese subjects were evaluated by multivariate or logistic regression analyses. Results: The proportion of obesity was 29.7% at a BMI cutoff point of 25kg/m(2) and 10.4% at 27.5kg/m(2). The proportion of MetS was greater in obese population and increased with higher obesity cutoff point, where men were more prevalent than women. The subjects with MetS showed higher age, glycated hemoglobin, insulin resistance, liver enzymes, and ferritin compared with metabolically healthy population in both obese genders. Factors associated with insulin level or presence of MetS were high trunk fat percentage, trunk-to-limb fat ratio, and trunk-to-leg fat ratio, but low limb fat percentage and leg fat percentage. Among body composition indices, trunk-to-limb fat ratio and trunk-to-leg fat ratio showed significantly high odds ratios for MetS in both obese genders regardless of BMI cutoff points. Conclusions: MetS in obese population concurrently increased with higher obesity cutoff point. Higher age, insulin resistance, liver enzymes, ferritin, and higher proportion of truncal fat mass-to-limb or leg fat mass significantly contribute to MetS, where trunk-to-limb fat ratio and trunk-to-leg fat ratio could be helpful in identifying and preventing MetS in the obese Korean population.