Ethnic and sex differences in the distributions of body mass index and waist circumference among adults: a binationally representative study in South Korea and the United States

Abstract

OBJECTIVE: The ethnic and sex differences in the distributions of body mass in-dex (BMI) and waist circumference (WC) among adults are largely unknown. Therefore, we aimed to investigate the percentiles of BMI and WC in groups divided according to age, sex, and eth-nicity.PATIENTS AND METHODS: We conducted a population-based binational study of adults aged >= 20 years based on data from two sourc-es: US National Health and Nutrition Examina-tion Survey (2015 to 2020) and Korea National Health and Nutrition Examination Survey (2016 to 2019).RESULTS: Weight, height, and WC were mea-sured in 13,144 American adults and 30,191 Ko-rean adults. Overall, BMI increased at younger ages and decreased at older ages, which indi-cates a reversed U-shaped relationship, and dif-fered in terms of age, sex, and ethnicity. Wom-en in the other Hispanic, non-Hispanic white, non-Hispanic black, and "other ethnic groups" showed a common BMI peak at ages 50-54 years. The patterns of WC distribution were sim-ilar to those of BMI distribution.CONCLUSIONS: In this binational represen-tative study, we found varied distributions of ethnic and sex differences in BMI and WC. Con-sidering the differences in these distributions may help improve individual and personalized treatment strategies.