title: Body composition assessment of undernourished older subjects by dual-energy x-ray absorptiometry and bioelectric impedance analysis.
abstract: BACKGROUND
  The prevention and treatment of diseases related to changes in body composition require accurate methods for the measurement of body composition. However, few studies have dealt specifically with the assessment of body composition of undernourished older subjects by different methodologies.
  
  
  OBJECTIVE
  To assess the body composition of undernourished older subjects by two different methods, dual energy x-ray absorptiometry (DXA) and bioelectric impedance (BIA), and to compare results with those of an eutrophic group.
  
  
  METHODS
  The study model was cross-sectional; the study was performed at the University Hospital of the School of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
  
  
  METHODS
  Forty-one male volunteers aged 62 to 91 years. The groups were selected on the basis of anamnesis, physical examination and nutritional assessment according to the Mini Nutritional Assessment (MNA) score. Body composition was assessed by DXA and BIA.
  
  
  RESULTS
  Body weight, arm and calf circumference, body mass index (BMI), fat free mass (FFM) and fat mass (FM) were significantly lower in the undernourished group as compared to the eutrophic group. There were no significant differences between FFM and FM mean values determined by DXA and BIA in both groups, but the agreement between methods in the undernourished group was less strong.
  
  
  CONCLUSIONS
  Our results suggest caution when BIA is to be applied in studies including undernourished older subjects. This study does not support BIA as an accurate method for the individual assessment of body composition.
authors.affiliation: Department of Internal Medicine, Division of General Internal and Geriatric Medicine, School of Medicine of Ribeirão Preto, University of Säo Paulo, Brazil. kavilaca@yahoo.com.br
authors.forename: K H C
authors.initials: KH
authors.lastname: Vilaça
authors.forename: F J A
authors.initials: FJ
authors.lastname: Paula
authors.forename: E
authors.initials: E
authors.lastname: Ferriolli
authors.forename: N K C
authors.initials: NK
authors.lastname: Lima
authors.forename: J S
authors.initials: JS
authors.lastname: Marchini
authors.forename: J C
authors.initials: JC
authors.lastname: Moriguti
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D001837:Body Weights and Measures; D001938:Brazil; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D044342:Malnutrition; D008875:Middle Aged; D015596:Nutrition Assessment; D012016:Reference Values; D015203:Reproducibility of Results