The relationship between body mass index and body cell mass in African-American, Asian, and Caucasian adults.

The objective of this study was to investigate the relationship between body mass index (BMI, kg/m2) and body cell mass (BCM) estimated from total body potassium (TBK) measured by whole body 40K counting in healthy 284 African-Americans (AA), 269 Asians (A) and 536 Caucasians (C) aged 18–107 years and to study the effects of age, sex, and race on the relationship. Body fat and fatfree mass (FFM) were measured by dual-energy X-ray absorptiometry (DXA). There was a significant positive correlation between BCM and BMI. For a given BMI, A had lower BCM but decreased less per year of age than AA and C, and males had higher BCM than females in each ethnic group. The fraction, BCM/FFM decreased with BMI in all subgroups by race, sex, and age, and males decreased more per age and AA decrease more than A and C. Not only the BCM–BMI relationship but also BCM/FFM vs. BMI is important to health. [ABSTRACT FROM AUTHOR]