title: Evaluation of the novel Tanita body-fat analyser to measure body composition by comparison with a four-compartment model.
abstract: The Tanita body-fat analyser is a novel device to estimate body fat, based on the principles of bioelectrical impedance. It differs from other impedance systems which use surface electrodes in that the subjects stand bare-footed on a metal sole-plate which incorporates the electrodes, hence impedance is measured through the legs and lower trunk. In 104 men and 101 women (16-78 years and BMI 16-41 kg/m2) the mean bias in body-fat mass measured using the Tanita body-fat analyser was 0.8 (2SD 7.9) kg relative to a four-compartment model. This is comparable to the other prediction techniques tested (conventional tetrapolar impedance -1.3 (2SD 6.9) kg, skinfold thicknesses 0.3 (2SD 7.4) kg, and BMI-based formulas -0.2 (2SD 9.0) kg and -0.6 (2SD 8.5) kg), but the agreement was poorer than for 'reference' methods to measure body fat (density 0.2 (2SD 3.7) kg, total body water -0.9 (2SD 3.4) kg and dual-energy X-ray absorptiometry 0.1 (2SD 5.0) kg). The present paper also describes the derivation of a new prediction equation for the calculation of body composition from the Tanita body-fat analyser. The equation incorporates sex, age, and a log-transformation of height, weight and the measured impedance to predict body fat measured by a four-compartment model. This approach is recommended in the derivation of other prediction equations in body composition analysis. Using this novel prediction equation the residual standard deviations were 4.8% for men and 3.3% for women. A similar analysis using data collected with a conventional tetrapolar system yielded residual standard deviations of 4.3% for men and 3.1% for women. This demonstrates that the practical simplicity of the novel Tanita method is not associated with a clinically significant decrement in performance relative to a traditional impedance device.
authors.affiliation: MRC Human Nutrition Research, Cambridge, UK. Susan.Jebb@mrc-hnr.cam.ac.uk
authors.forename: S A
authors.initials: SA
authors.lastname: Jebb
authors.forename: T J
authors.initials: TJ
authors.lastname: Cole
authors.forename: D
authors.initials: D
authors.lastname: Doman
authors.forename: P R
authors.initials: PR
authors.lastname: Murgatroyd
authors.forename: A M
authors.initials: AM
authors.lastname: Prentice
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000465:Algorithms; D000886:Anthropometry / Q000295:instrumentation*; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D015203:Reproducibility of Results; D017678:Sex Distribution; D012885:Skinfold Thickness