Racial differences in body fat distribution among reproductive-aged women

We examined the influence of race/ethnicity on body fat distribution for a given body mass index (BMI) among reproductive-aged women. Body weight, height, and body fat distribution were measured with a digital scale, wall-mounted stadiometer, and dual-energy x-ray absorptiometry, respectively, on 708 healthy black, white, and Hispanic women 16 to 33 years of age. Multiple linear regression was used to model the relationship between race/ethnicity and different body fat distribution variables after adjusting for BMI, age at menarche, and demographic and lifestyle variables. For a given BMI, white women had the highest total fat mass (FM_total), trunk fat mass (FM_trunk), and leg fat mass (FM_leg), whereas Hispanic women had the highest percentage of FM_trunk (%FM_trunk) and trunk-to-limb fat mass ratio (FMR_{trunk-to-limb}). Conversely, black women had the lowest FM_total, FM_trunk, percentage body fat mass (%FM), %FM_trunk, and FMR_{trunk-to-limb}, and the highest percentage of FM_leg. The %FM was similar in whites and Hispanics and lower in blacks. The race × BMI interactions were significant for almost all of the body fat distribution variables. Increasing in differences with increasing BMI were apparent between blacks and whites in FM_trunk, %FM_trunk, FMR_{trunk-to-limb}, %FM_leg, and %FM, and between blacks and Hispanics in FM_trunk, %FM_trunk, FMR_{trunk-to-limb}, and FM_leg. In summary, the distribution of body fat for a given BMI differs by race among reproductive-aged women. These findings raise questions regarding universally applied BMI-based guidelines for obesity and have implications for patient education regarding individual risk factors for cardiovascular disease and metabolic complications.