20-Year Trends in Metabolic Syndrome Among Korean Adults From 2001 to 2020

BACKGROUND: The number of people with metabolic syndrome (MetS) is increasing worldwide, and many socioeconomic and environmental factors contribute to this. OBJECTIVES: The authors investigated tangible trends in the prevalence of MetS using the 2001 to 2020 versions of the Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: In these surveys, stratified multistage sampling designs were used to approximate the entire population. Blood pressure, waist circumference, and lifestyle variables were examined in a standardized fashion. Metabolic biomarkers were measured in a central laboratory operated by the Korean government. RESULTS: The age-adjusted prevalence of MetS increased significantly from 27.1% in 2001 to 33.2% in 2020. It was more prevalent in men (25.8%→40.0%) but did not change in women (28.2%→26.2%). Among the 5 MetS components, the proportions of high glucose level and large waist circumference increased substantially by 17.9% and 12.2% over 20 years, while high-density lipoprotein cholesterol levels increased significantly, resulting in a decrease in low high-density lipoprotein cholesterol by 20.4%. Caloric intake derived from carbohydrates decreased from 68.1% to 61.3%, while fat consumption increased from 16.7% to 23.0%. Notably, sugar-sweetened beverage consumption showed an almost 4-fold increase from 2007 to 2020, while physical activity levels decreased by 12.2% from 2014 to 2020. CONCLUSIONS: Glycemic dysregulation and abdominal obesity were key features contributing to the increased prevalence of MetS observed in Korean men during the past 20 years. Rapid economic and socioenvironmental changes in this period may be involved in this phenomenon. Understanding these changes in MetS could be valuable for other countries undergoing such socioeconomic transformation.