Title of article:

Body composition measurements in females with leg-to-leg bioelectrical impedance analsys compared to DEXA

Authors: Austin MA, Heymsfield SB, Nieman DC.
Source: Tanita Corporation website1. 1998.

Abstract

Objective: This study determined the validity of the leg-to-leg bioelectrical impedance analysis (BIA) system (Tanita Body Fat Analyzer, TBF 105, Tanita Corporation of America, Inc., Arlington Heights, IL) in estimated body composition in a hetergeneous group of females ( n=255) [mean±SD, age, 42.0±15.6 yr (range, 18-88); body mass, 74.8±16.7 kg (33.8-120.5 kg); height, 162±7 cm (144-179 cm); body mass index, 28.4±6.0 kg/m2 (15.9-41.9 kg/m2)].
Methods: Fat-free mass (FFM) and percent body fat (BF) were estimated using BIA and dual energy X-ray absorptiometry (DEXA) ( Lunar DPX, Lunar Radiation Corp, Madison, WI). Prior to testing, subjects were required to adhere to standard BIA testing guidelines, and bioelectrical impedance was measured in subjects standing erect with bare feet on the analyzer's footpads, and wearing minimal clothing. FFM and BF from BIA were calculated using the prediction equation supplied by the manufacturer (which uses body mass, age, and an impedance index, height2/impedance).
Results: A Bland-Altman plot of difference between FFM and BF measured by DEXA and BIA versus average FFM and BF by the two methods showed no significant systematic difference ( mean difference, -1.2±3.0 kg, and 1.7±4.2%, respectively). FFM was estimated at 44.8±5.6 kg with DEXA, and 46.0±4.8 kg with BIA (r=0.84, p<0.001; SEE 3.0 kg). BF was estimated at 38.2±10.2% with DEXA, and 36.5±9.8% with BIA (r=0.91, p<0.001; SEE 4.2%). These data indicate that the leg-to-leg bioelectrical impedance system accurately assesses FFM and BF in females compared to DEXA. Supported by a grant from the Tanita Corporation of America, Inc

Comments and Key points

Although this study was industry sponsored by the Tanita Corporation, and the results were published on the Tanita website1, the scientific detail presented seems credible.

It demonstrates that body fat measurements made with the Bio-Electrical Impedence technique, using the inexpensive Tanita TBF-105 body fat monitor scales, were able to accurately measure females body fat percentage. There was no significant difference compared to DEXA measurements.

 

References

  1. http://www.tanita.com/professional/abstracts/abstract_main.html

Review & comments by Steven B. Halls, MD, Last edited 26-May-2008 Copyright.

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