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Abstract Background Overall and abdominal obesity are associated with increased risks of various chronic diseases. A comprehensive understanding of nationwide trends and contributing factors is necessary to reduce obesity burdens. Methods We conducted hierarchical age-period-cohort analyses using cross-classified random-effects models on measured body mass index (BMI) and waist circumference (WC) data from a nationally representative sample of 86 806 Korean adults aged 19–79 years in the Korea National Health and Nutrition Examination Survey 2007–2022. Results In 2007–2022, there were overall increasing trends in age-standardized mean BMI and WC and prevalence of overall and abdominal obesity. When stratified by sex, the age-standardized mean BMI and WC increased among men (BMI: from 24.1 to 25.2 kg/m2; WC: from 84.6 to 88.6 cm), whereas only small changes were observed among women (BMI: from 23.1 to 23.2 kg/m2; WC: from 78.8 to 77.9 cm). Mean BMI and WC increased with age through middle adulthood in men and late adulthood in women. After controlling for age and period effects, mean BMI and WC were lowest among the birth cohorts of the late 1950s and 1970s and increased in more recent birth cohorts. Among men, mean BMI and WC were higher in higher socioeconomic subgroups (higher income, higher education, urban areas), but, among women, mean BMI and WC were higher in lower socioeconomic subgroups. Conclusions To reduce obesity-related disease burdens in Korea, tailored interventions are needed to target the most vulnerable populations, such as younger generations, men of higher socioeconomic subgroups, and women of lower socioeconomic subgroups.
Jeong et al. (2026) studied this question.