title: [Variability in bioelectrical impedance assessment of body composition depending on measurement conditions: influence of fast and rest].
abstract: BACKGROUND
  Bioelectrical Impedance Assessment (BIA) is one of the main tools to measure body composition. BIA is recommended in fasting and after 60 minutes of rest; however, this cannot always be guaranteed in healthcare practice.
  
  
  OBJECTIVE
  To establish the reliability of the body composition parameters assessed with BIA under different physiological conditions: fast + rest, fast + no-rest and no-fast + no-rest in healthy volunteers.
  
  
  METHODS
  Transversal study including 25 healthy volunteers aged 18-34 (12 men, 13 women). A BIA was performed under three different conditions: 1) fast + 60 minute rest in cubito supino (gold standard), 2) fast + no rest and 3) no fast + no rest. The collected parameters were: lean mass and fat mass (Kg) and body water (in liters and as body weight percentage). The intraclass correlation coefficient (ICC) was applied for the assessment of concordance within the different measurements.
  
  
  RESULTS
  Compared to the gold standard, the difference in lean mass means in the condition of fast + no-rest, was -0.15 (DE 1.44) in men and 0.98 (DE 1.36) in women; fat mass decreased in 0.06 (DE 1.55) in men and 0.82 (DE 1.5) in women; ICC ranged between 0.826-0.995 in all comparisons. In the condition of no-fast + no rest, lean mass decreased an average of 0.05 (DE 0.33) in men and it increased 0.62 (DE 0.46) in women; fat mass decreased 0.57 (DE 0.82) in men and 0.46 (DE 0.60) in women; ad ICC ranged between 0.942 and 0.999, except in body water in men, where it was 0.340.
  
  
  CONCLUSIONS
  Although relevant, the differences observed in parameters from BIA when comparing the gold standard condition (fast + rest) with the other conditions (fast + no-rest and no-fast + no-rest) are of little magnitude. In clinical practice, the assessment of body composition allows to take decisions when planning treatment for patients with a poor physical condition.
  
  
  CONCLUSIONS
  The reliability of the parameters acquired via BIA within different physiological conditions of fast and rest is excellent (CCI >0.75) in healthy adults aged 19-34. Although general recommendations on the use of BIA devices must be kept in place, the conditions of the performance could be modified according to the context and assuming a small difference of little clinical relevance.
authors.affiliation: Servicio de Neumología. Fundación Cardiovascular de Colombia, Santander. Colombia.. emarco@parcdesalutmar.cat.
authors.forename: Diana Isabel
authors.initials: DI
authors.lastname: Cáceres
authors.affiliation: Grupo de Investigación en Rehabilitación, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona.Rehabilitación, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona. Rehabilitación, Parc de Salut Mar (Hospital del Mar - Hospital de l'Esperança), Barcelona.. emarco@parcdesalutmar.cat.
authors.forename: Monique
authors.initials: M
authors.lastname: Sartor-Messagi
authors.affiliation: Facultad de Medicina, Universidad Autònoma de Barcelona, Barcelona. Servicio de Neumología, Hospital del Mar, Barcelona. Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III (ISCIII), Madrid. Spain.. emarco@parcdesalutmar.cat.
authors.forename: Diego Agustín
authors.initials: DA
authors.lastname: Rodríguez
authors.affiliation: Grupo de Investigación en Rehabilitación, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona. Facultad de Medicina, Universidad Facultad de Medicina, Universidad. emarco@parcdesalutmar.cat.
authors.forename: Ferran
authors.initials: F
authors.lastname: Escalada
authors.affiliation: Servicio de Neumología, Hospital del Mar, Barcelona. Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III (ISCIII), Madrid. Spain.. emarco@parcdesalutmar.cat.
authors.forename: Joaquim
authors.initials: J
authors.lastname: Gea
authors.affiliation: Servicio de Neumología. Fundación Cardiovascular de Colombia, Santander. Colombia. Facultad de Ciencias de la Salud (CEXS), Universitat Pompeu Fabra, Barcelona.. emarco@parcdesalutmar.cat.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Orozco-Levi
authors.affiliation: Grupo de Investigación en Rehabilitación, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona. Facultad de Medicina, Universitat Internacional de Catalunya, Barcelona.. emarco@parcdesalutmar.cat.
authors.forename: Ester
authors.initials: E
authors.lastname: Marco
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D001823:Body Composition; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012146:Rest; D055815:Young Adult