title: Total body water in children with cystic fibrosis using bioelectrical impedance.
abstract: BACKGROUND
  The aim of this study was to assess the ability of commercially available single frequency bioelectrical impedance analysis (BIA) to predict total body water and hence body composition in a cohort of children with cystic fibrosis (CF).
  
  
  METHODS
  In 56 (31 girls, 25 boys) children aged 4 to 18 years, total body water was predicted using BIA and measured using a deuterium oxide dilution technique. Each child provided a urine sample before consuming 0.5 g/kg body weight 10% deuterium oxide. A further urine sample was collected between 4 and 6 h later.
  
  
  RESULTS
  There was a mean bias between predicted and measured total body water of 1.1 L. The bias was consistent across the range of total body water measured in this study. The relationship between height2/impedance and measured total body water was TBW=0.35+0.74*height2/impedance. This equation is similar to other equations found in healthy children.
  
  
  CONCLUSIONS
  We have shown that a commercially available bioelectrical device underestimates measured total body water. We have generated a prediction equation for the population studied, which we believe might enhance the accuracy of the method in children with cystic fibrosis.
authors.affiliation: School of Medicine, University of Maastricht, Maastricht, The Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: Puiman
authors.forename: P
authors.initials: P
authors.lastname: Francis
authors.forename: H
authors.initials: H
authors.lastname: Buntain
authors.forename: C
authors.initials: C
authors.lastname: Wainwright
authors.forename: B
authors.initials: B
authors.lastname: Masters
authors.forename: P S W
authors.initials: PS
authors.lastname: Davies
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D001834:Body Water / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000503:physiopathology*; D017666:Deuterium Oxide; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007201:Indicator Dilution Techniques; D008297:Male; D011237:Predictive Value of Tests
chemical_list: D017666:Deuterium Oxide