Clinical and Preclinical Obesity in Korean Adults from 2014 to 2023.

backgruoundA new diagnostic framework for clinical obesity, proposed by the Lancet Commission, defines obesity as excess adiposity with organ dysfunction, offering a more functional assessment than traditional body mass index (BMI)-based classification. However, it has not been applied to Asian populations, where obesity-related complications arise at lower BMI thresholds.

methodsWe analyzed 57,863 Korean adults aged ≥20 years from the 2014 to 2023 Korea National Health and Nutrition Examination Survey (KNHANES), a nationally representative, cross-sectional dataset. Clinical obesity was defined as excess adiposity with ≥1 obesity-related complication or functional limitation; preclinical obesity was defined as excess adiposity without complications. Age, sex, and temporal trends were examined and compared with BMI-based classifications using complex sampling weights and age-standardization.

resultsThe prevalence of clinical obesity and preclinical obesity was 31.2% and 8.1%, respectively. Among those with BMI-defined obesity (≥25.0 kg/m²), 20.1% had no complications, while 19.4% of overweight individuals (BMI 23.0-24.9 kg/m²) met clinical obesity criteria. Clinical obesity increased with age despite stable BMI, driven by metabolic and functional decline. Cancer prevalence was highest among individuals with clinical obesity (1.77%). Applying Western waist circumference cutoffs drastically reduced the estimated prevalence of clinical obesity to 13.1%. Longitudinal analyses showed a rising trend in clinical obesity over ime.

conclusionThis is the first large-scale study to apply the clinical obesity framework in an Asian population. The framework identifies high-risk individuals missed by BMI al.