title: Bioimpedance in 7-year-old children: validation by dual X-ray absorptiometry - part 1: assessment of whole body composition.
abstract: OBJECTIVE
  To validate the bioimpedance analyzer (BIA) Tanita BC-418 for its clinical and epidemiological use in children compared to dual-energy X-ray absorptiometry (DXA).
  
  
  METHODS
  A cross-sectional validation study was performed in 7-year-old children using anthropometry, BIA and DXA. Whole body fat and lean masses were assessed through BIA (BIAoutputs) and DXA. Fat mass index (FMI) was calculated. Predictive equations were derived from raw impedance and anthropometric measures; results obtained from these predictive equations (BIAregressions) were also compared to DXA.
  
  
  RESULTS
  171 children (84 boys) were studied. BIAoutputs and DXA results revealed small differences for lean mass (1%) and moderate differences for fat mass (13%). BIAregressions results showed small differences for both body lean and fat masses (0.21 and 4.62%, respectively). Sensitivity and specificity to correctly classify children >90.8th percentile of FMI was 84.6 (64.3-94.9) and 95.9% (90.8-98.3) for BIAoutputs and 100 (98.1-100.0) and 95.9% (92.3-99.4) for BIAregressions, respectively.
  
  
  CONCLUSIONS
  Tanita BC-418 may be valid for epidemiological studies assessing whole body composition. Its measurements may help in the diagnosis and monitoring of childhood overweight and obesity. The validation of predictive equations in specific populations may increase the precision of the technique.
authors.affiliation: Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus, Spain.
authors.forename: Veronica
authors.initials: V
authors.lastname: Luque
authors.forename: Ricardo
authors.initials: R
authors.lastname: Closa-Monasterolo
authors.forename: Carmen
authors.initials: C
authors.lastname: Rubio-Torrents
authors.forename: Marta
authors.initials: M
authors.lastname: Zaragoza-Jordana
authors.forename: Natalia
authors.initials: N
authors.lastname: Ferré
authors.forename: Mariona
authors.initials: M
authors.lastname: Gispert-Llauradó
authors.forename: Joaquin
authors.initials: J
authors.lastname: Escribano
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D009765:Obesity / Q000175:diagnosis; D050177:Overweight / Q000175:diagnosis; D016032:Randomized Controlled Trials as Topic; D012680:Sensitivity and Specificity; D013030:Spain