Bioelectrical impedance analysis to assess body composition in obese adult women: the effect of ethnicity.
OBJECTIVE
To examine whether the accuracy of bioelectrical impedance analysis (BIA) to estimate body composition in overweight women is affected by the ethnicity of the individuals.


METHODS
Cross-sectional design to compare body composition estimated by BIA to body composition measured by dual energy x-ray absorptiometry (DEXA), which was the reference method.


METHODS
One hundred twenty three overweight women participated in this study, of which 43 women were African-American (aged 37.2+/-5.6 y; BMI, 32.3+/-4.9 kg/m2) and 80 were Caucasian (aged 36.1+/-5.7 y; BMI, 31.9+/-3.5 kg/m2).


METHODS
Body composition was estimated from BIA using both a generalized and an obesity-specific equation. These estimations were compared to body composition measured by DEXA, which was the reference method.


RESULTS
The generalized BIA equation underestimated lean body mass (LBM) by 2.6+/-3.1 kg in Caucasian women and 0.4+/-3.2 kg in African-American women, with the difference between the ethnic groups being significant (P < 0.001). The obesity-specific equation underestimated LBM in Caucasians by 0.9+/-3.1 kg and overestimated LBM in African-Americans by 1.2+/-2.8 kg (P < 0.001). An ethnic-specific equation is proposed, and cross-validation of this equation indicates that it provides a reasonable estimate of body composition in overweight women.


CONCLUSIONS
The accuracy of BIA to estimate body composition appears to be affected by the ethnicity of the individual. Therefore, an ethnic-specific equation for overweight women is proposed. However, further validation of this prediction model in an ethnically diverse population is necessary.
Jakicic
J M
JM
University of Pittsburgh School of Medicine, PA 15213, USA.
Wing
R R
RR
Lang
W
W
D015502:Absorptiometry, Photon; D000328:Adult; D044383:Black People; D001823:Body Composition / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D009765:Obesity / Q000208:ethnology / Q000503:physiopathology*; D012044:Regression Analysis; D044465:White People; D001741:Black or African American