Binational comparison of depressive symptom severity and metabolic syndrome in nationally representative adults from South Korea and the United States.

PURPOSE: Given limited recent nationally representative evidence on depression and metabolic syndrome (MetS), we compared this association in South Korea and the United States (US). METHODS: We analyzed data from the Korea National Health and Nutrition Examination Survey (KNHANES, 2014-2022) and the National Health and Nutrition Examination Survey (NHANES, 2013-2020). Depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9; categorized as low [0-9], moderate [10-14], or high [15-27]). MetS was defined by the National Cholesterol Education Program Adult Treatment Panel III. Weighted logistic regression analyses were performed to calculate weighted odds ratios (wORs) and 95% confidence intervals (CIs) by PHQ-9 category. RESULTS: We included 25,207 KNHANES participants and 16,447 NHANES participants. MetS prevalence was higher in the high PHQ-9 group (South Korea, 38.19% [95% CI, 33.05-43.33]; the US, 43.20% [36.73-49.68]). Estimated wORs for MetS generally increased at higher PHQ-9 scores. High versus low PHQ-9 scores were associated with higher MetS odds in both countries (South Korea: wOR, 1.34 [95% CI, 1.07-1.66]; the US: 1.44 [1.09-1.91]), with a numerically higher estimate in the US. Subgroup analyses suggested that differences in MetS prevalence across PHQ-9 categories were more evident among females, adults aged 40-64 years, and participants with lower household income. CONCLUSIONS: These findings underscore the need to incorporate depressive symptom assessment into MetS prevention and management, with strategies tailored to national contexts.