The prevalence trend of metabolic syndrome and its components and risk factors in Korean adults: results from the Korean National Health and Nutrition Examination Survey 2008-2013

Background: Abnormalities in the clinical markers of metabolic syndrome (MS) are associated with the development of cardiovascular disease, type 2 diabetes mellitus, and some cancers. MS prevalence in Korea increased between the mid-1990s and mid-2000s; however, no data on the recent trends of MS prevalence are available. Thus, we aimed to investigate the prevalence of MS, the five components of MS, and the related risk factors in Korean adults by using recent data. Methods: Data from the Korean National Health and Nutrition Examination Survey conducted between 2008 and 2013 were used. The revised National Cholesterol Education Program criteria were used for defining MS. A multivariate logistic regression analyses was used to estimate the relationship between the related risk factors including behaviors, dietary factors, and the prevalence of MS. Results: A total of 34,587 men and women were included in the analysis. Age-adjusted prevalence of MS in 2013 was 28.9% without a significant increasing or decreasing trend between 2008 and 2013. Among the five components of MS, abdominal obesity decreased in both men and women (annual percent change: -2.0 and -2.5%, respectively), the decrease being significant only in women, whereas blood pressure and blood glucose significantly increased in men (+1.9 and +2.7%, respectively). Age and obesity (odds ratio = 6.7, 95% confidence interval = 5.9-7.5 for body mass index >= 25 kg/m(2) vs. body mass index < 25 kg/m(2)) were associated with increased MS risk in both men and women. Smoking and alcohol drinking were significantly associated with increased MS risk in men, and association between MS and vitamin D deficiency was at the edge of statistical significance. Higher education and income level were significantly associated with decreased MS risk in women. During this period, smoking rate and physical activity, sodium intake, and serum vitamin D level significantly decreased. Education level, calorie intake, and intake of carbohydrate, fat, protein and calcium significantly increased. Conclusion: Several factors contribute to the stable MS prevalence-on the one hand, increased prevalence of high blood sugar, high blood pressure, calorie intake, and physical inactivity, and on the other hand, decreased prevalence of abdominal obesity and smoking. Lifestyle interventions to prevent and control non-communicable diseases should be implemented at the national level to reduce the burden of MS.