Metabolic syndrome severity score in Korean adults: Analysis of the 2010-2015 Korea National Health and Nutrition Examination Survey

Background: Continuous metabolic syndrome (MS) severity scores that can track metabolic risk in individuals over time have been developed for Western populations. The present study aimed to develop gender- and age-specific equations for MS severity scores in Korean adults. Methods: Using data from the Korea National Health and Nutrition Examination Surveys (KNHANES) IV (2010-2012) and VI (2013-2015), we performed a confirmatory factor analysis of single MS factor that allowed for differential loadings across groups to generate gender- and age-specific, continuous MS severity scores. Then, we validated this equation in a different dataset of Korean adults. Results: In confirmatory analysis, waist circumference had the highest factor loading, indicating that waist circumference had the strongest correlation with MS among Korean adults. Lower factor loadings (< 0.4) among Korean adults aged 40-59 years were noted for systolic blood pressure and fasting glucose. MS severity score values were significantly correlated with metabolic parameters, including high-sensitivity C-reactive-protein, glycated hemoglobin, and homeostasis model assessment of insulin resistance. Furthermore, MS severity scores well predicted traditional MS according to receiver operating characteristic analysis in a validation dataset (KNHANES VII). In a longitudinal cohort dataset, participants diagnosed with Adult Treatment Program III (ATP-III) MS after an initial assessment had progressively higher baseline MS severity scores in relationship to their time until ATP-III MS diagnosis. Conclusion: The new MS severity score equations for Korean adults proposed in this study provide a clinically-accessible continuous measure of MS for potential use in identifying adults at higher risk for MS-related diseases and following changes within individuals over time.