title: Development of a single-frequency bioimpedance prediction equation for fat-free mass in an adult Indigenous Australian population.
abstract: OBJECTIVE
  To describe the development of a single-frequency bioimpedance prediction equation for fat-free mass (FFM) suitable for adult Aboriginal and Torres Strait Islander peoples with and without diabetes or indicators of chronic kidney disease (CKD).
  
  
  METHODS
  FFM was measured by whole-body dual-energy X-ray absorptiometry in 147 adult Indigenous Australians. Height, weight, body circumference and resistance were also measured. Adults with and without diabetes and indicators of CKD were examined. A random split sample with internal cross-validation approach was used to predict and subsequently validate FFM using resistance, height, weight, age and gender against measured FFM.
  
  
  RESULTS
  Among 147 adults with a median body mass index of 31 kg/m(2), the final model of FFM was FFM (kg)=0.432 (height, cm(2)/resistance, ohm)-0.086 (age, years)+0.269 (weight, kg)-6.422 (if female)+16.429. Adjusted R(2) was 0.94 and the root mean square error was 3.33 kg. The concordance was high (rc=0.97) between measured and predicted FFM across a wide range of FFM (31-85 kg).
  
  
  CONCLUSIONS
  In the context of the high burden of diabetes and CKD among adult Indigenous Australians, this new equation for FFM was both accurate and precise and based on easily acquired variables (height, weight, age, gender and resistance) among a heterogeneous adult cohort.
authors.affiliation: 1] Division of Medicine, Royal Darwin Hospital, Darwin, NT, Australia [2] Charles Darwin University, Menzies School of Health Research, Darwin, NT, Australia.
authors.forename: J T
authors.initials: JT
authors.lastname: Hughes
authors.affiliation: 1] Division of Medicine, Royal Darwin Hospital, Darwin, NT, Australia [2] Charles Darwin University, Menzies School of Health Research, Darwin, NT, Australia.
authors.forename: L J
authors.initials: LJ
authors.lastname: Maple-Brown
authors.affiliation: School of Population Health, University of Melbourne, Melbourne, VIC, Australia.
authors.forename: L S
authors.initials: LS
authors.lastname: Piers
authors.affiliation: Measure Up, Sydney, NSW, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Meerkin
authors.affiliation: School of Population Health, Sansom Institute, University of South Australia, Brisbane, QLD, Australia.
authors.forename: K
authors.initials: K
authors.lastname: O'Dea
authors.affiliation: School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia.
authors.forename: L C
authors.initials: LC
authors.lastname: Ward
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D001315:Australia; D001823:Body Composition; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D003920:Diabetes Mellitus / Q000503:physiopathology; D017097:Electric Impedance; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000503:physiopathology
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