title: Bioelectrical impedance analysis to assess body composition in obese adult women: the effect of ethnicity.
abstract: 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.
authors.affiliation: University of Pittsburgh School of Medicine, PA 15213, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Jakicic
authors.forename: R R
authors.initials: RR
authors.lastname: Wing
authors.forename: W
authors.initials: W
authors.lastname: Lang
mesh_terms: 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