title: Prediction of body fat in a dolescents: comparison of two electric bioimpedance devices with dual-energy X-ray absorptiometry.
abstract: BACKGROUND
  An accurate estimate of body composition is important in assessing and monitoring the nutritional status of adolescents.
  
  
  OBJECTIVE
  To compare the accuracy of 2 electrical bioimpedance devices with that of dual-energy X-ray absorptiometry (DXA) to predict body fat in Brazilian adolescents.
  
  
  METHODS
  We evaluated 500 adolescents aged between 10 and 19 years, stratified by sex and divided into overweight and non-overweight groups. The percentage of body fat (%BF) was estimated using 2 types of electrical bioimpedance devices: BIA1 (horizontal tetrapolar bioimpedance equipment) and BIA2 (vertical 8-electrode bioimpedance equipment), as well as by DXA. A Bland- Altman plot was used to calculate the total errors and standard errors of estimate.
  
  
  RESULTS
  Considering BMI for age, 19.4% were overweight and 47.4% as assessed by %BF of DXA were overweight. The %BF estimated by BIA2 correlated well (p < 0.05) with the %BF predicted by DXA, and only the total errors for BIA2 in the overweight group were acceptable (≤2.5%). The standard errors of estimate was <3.5%, with the lowest values observed for BIA2. Both BIA1 and BIA2 underestimated the %BF in overweight adolescents, while overestimating the %BF in male adolescents of normal weight.
  
  
  CONCLUSIONS
  The BIA2 was found to be more effective in the evaluation of body fat. Regardless of the method used, the results should be carefully interpreted when assessing the body composition of adolescents.
authors.affiliation: Department of Pharmacy and Nutrition - Universidade Federal do Espírito Santo.. elianefariaufes@gmail.com.
authors.forename: Eliane Rodrigues
authors.initials: ER
authors.lastname: de Faria
authors.affiliation: Universidade Federal de Viçosa..
authors.forename: Franciane Rocha
authors.initials: FR
authors.lastname: de Faria
authors.affiliation: Universidade Federal de Viçosa..
authors.forename: Vivian Siqueira Santos
authors.initials: VS
authors.lastname: Gonçalves
authors.affiliation: Department of Nutrition and Health - Universidade Federal de Viçosa. Brazil..
authors.forename: Sylvia do Carmo Castro
authors.initials: Sdo C
authors.lastname: Franceschini
authors.affiliation: Department of Nutrition and Health - Universidade Federal de Viçosa. Brazil..
authors.forename: Maria do Carmo Gouveia
authors.initials: Mdo C
authors.lastname: Peluzio
authors.affiliation: Department of Nutrition and Health - Universidade Federal de Viçosa. Brazil..
authors.forename: Luciana Ferreira da Rocha
authors.initials: LF
authors.lastname: Sant'Ana
authors.affiliation: Department of Nutrition and Health - Universidade Federal de Viçosa. Brazil..
authors.forename: Silvia Eloiza
authors.initials: SE
authors.lastname: Priore
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000273:Adipose Tissue / Q000033:anatomy & histology*; D000293:Adolescent; D001823:Body Composition; D015992:Body Mass Index; D001938:Brazil; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests