Background

The number of people with obesity and/or metabolic syndrome is increasing in Korea with the western lifestyle. In this study, we compared the change of obesity, metabolic syndrome(Mets), and phenotypes for 10 years with Korea National Health and Nutrition Examination Survey (KNHANES) 2008 and 2017 dataset.

Methods

We investigated the trends of obesity and Mets prevalence over 10 years using sampling weight methods based on KNHANES 2008 and 2017. Of the 11994 people (2008: 6251 and 2017:5743) were included in the present study. According to Asia Pacific regional guidelines, obesity was defined as a body mass index (BMI) ≥ 25 kg/m2. Mets was defined as having 3 or more disorders in the following measurements: waist circumference, blood pressure, fasting triglycerides, high-density lipoprotein serum cholesterol, and glucose.

Results

The mean BMI was increased from 22.53±0.05 to 23.03±0.05 between 2008 and 2017. At same times, the prevalence of obesity was increased from 25.7% to 30.1% (p<0.001), but Mets was not changed (22.2% vs. 22.7%, p=0.592). The prevalence of Mets in non-obese people was decreased from 11.5% to 9.9% (p=0.024) but in obese people not changed (45.9% vs. 46.7%, p=0.651). In multiple-regression analysis with adjusting age and body mass index, the risk for Mets was decreased 23.8% (95% CI: 0.679 to 0.857, p<0.001). This change only observed in non-obese people (OR=0.645, 95% CI: 0.545 to 0.764, p<0.001), but not in obese people (OR=0.883, 95% CI: 0.754 to 1.035, p=0.125). In the receiver operating characteristic (ROC) analysis, the optimal cut-off value for BMI to discriminate Mets was slightly increased from 24.3 Kg/m2 (sensitivity 71.2%, specificity 71.2%) at 2008 to 24.6 Kg/m2 (sensitivity 73.8%, specificity 72.7%) at 2019.

Conclusions

Last 10 years, Korean are becoming more obese, but fortunately the prevalence of Mets not change in obese people and decreased in non-obese people. We postulate that Korean are adopting the fatness in non-obese people to some extent.