title: Efficacy of specific bioelectrical impedance vector analysis (BIVA) for assessing body composition in the elderly.
abstract: OBJECTIVE
  This study aimed to ascertain the efficacy of bioelectrical impedance vector analysis (BIVA) in assessing body composition in the elderly by comparing findings with the results of dual-energy X-ray absorptiometry (DXA), and to test an analytical variant of the method (specific BIVA).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  The sample comprised 207 free-living elderly individuals (75 men and 132 women) aged 65 to 93 years.
  
  
  METHODS
  Anthropometric and bioelectrical measurements were taken according to standard criteria. BIVA was applied using the 'classic' procedure and correcting bioelectrical values for body geometry to obtain an estimate of the whole-body impedivity. DXA was used as a reference body composition assessment method. BIVA (classic and specific values) and DXA findings were compared using Student's t and Hotelling's T2 tests, and Pearson's correlation coefficient.
  
  
  RESULTS
  In both sexes, BIVA distinguished between individuals with different amounts of fat and fat-free mass (lean mass including bone mineral content), according to DXA, but not between those with different proportions of fat mass (FM%). Specific bioelectrical values detected changes in body composition.
  
  
  CONCLUSIONS
  BIVA should be used with caution for evaluating body composition in the elderly. Specific bioelectrical values proved effective, showing promise as a methodological variant of BIVA, suitable for identifying age-related changes in body fatness.
authors.affiliation: Department of Environmental and Life Sciences, Anthropological Science Section, University of Cagliari, Cittadella Universitaria, 09042 Monserrato (Cagliari), Italy. emarini@unica.it
authors.forename: E
authors.initials: E
authors.lastname: Marini
authors.forename: G
authors.initials: G
authors.lastname: Sergi
authors.forename: V
authors.initials: V
authors.lastname: Succa
authors.forename: B
authors.initials: B
authors.lastname: Saragat
authors.forename: S
authors.initials: S
authors.lastname: Sarti
authors.forename: A
authors.initials: A
authors.lastname: Coin
authors.forename: E
authors.initials: E
authors.lastname: Manzato
authors.forename: R
authors.initials: R
authors.lastname: Buffa
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry / Q000379:methods*; D001823:Body Composition; D015992:Body Mass Index; D015519:Bone Density; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D009752:Nutritional Status