Cross-calibration of eight-polar bioelectrical impedance analysis versus dual-energy X-ray absorptiometry for the assessment of total and appendicular body composition in healthy subjects aged 21-82 years

Abstract

Eight-polar BIA offers accurate estimates of total and appendicular body composition. The attractive hypothesis that eight-polar BIA is influenced minimally by age and sex should be tested on larger samples including younger individuals.

Body water distribution in severe obesity and its assessment from eight-polar bioelectrical impedance analysis

“…The regression lines had similar slopes and intercepts (data not shown), confirming the manufacturer's indication that this apparent violation of the conduction pathways is expected to have a minimal effect on the assessment of body composition. The within-day precision of InBody 3.0 in three obese subjects was p2.0 O, a value similar to that observed in nonobese subjects (Bedogni et al, 2002;Malavolti et al, 2003).…”

“…Even if the use of multifrequency instruments may change this evidence, the use of an impedance-meter is clearly not justified in these circumstances. However, the present study and our experience so far (Malavolti et al, 2003) suggest that eight-polar BIA is substantially better than Wt as an indicator of body composition. As we have suggested elsewhere (Malavolti et al, 2003), unique characteristics of eight-polar BIA that may contribute to its very low dependency from Wt are: (1) the use of tactile electrodes, avoiding problems connected with adhesive electrodes, (2) the fact that whole-body eight-polar R is the sum of segmental resistances obtained with a 5-cylinder model of the human body ( Figure 1) and, (3) the insensitivity of eight-polar BIA to subject's posture.…”

“…Eight-polar BIA is a recently introduced technique with three interesting characteristics: (1) the use of very practical tactile electrodes for measuring segmental resistances at multiple frequencies, (2) the absence of need to standardize subject's posture before analysis and, (3) the rapidity of measurements. We have shown that eight-polar BIA offers accurate estimates of TBW and appendicular body composition in adult and elderly subjects (Bedogni et al, 2002;Malavolti et al, 2003). However, the accuracy of eightpolar BIA in detecting TBW and ECW in conditions of altered body water distribution is at present unknown.…”

“…We avoided measuring segmental lengths and calculating segmental RIs because the above approach is at least as accurate as the segmental one and less time consuming (Bedogni et al, 2002;Malavolti et al, 2003). No caution was taken to standardize the subject's posture before BIA, as suggested by the manufacturer.…”

Evaluation of air-displacement plethysmography and bioelectrical impedance analysis vs dual-energy X-ray absorptiometry for the assessment of fat-free mass in elderly subjects

“…Calibration of indirect techniques against direct methods provides the most common means of performing epidemiological studies of body composition (Heymsfield et al, 2000). Dual-energy X-ray absorptiometry (DXA) compares well with reference body composition methods and is increasingly used to evaluate body composition and to calibrate indirect techniques (Gallagher et al, 1997;Salamone et al, 2000;Malavolti et al, 2003). Air-displacement plethysmography (ADP) is a relatively new technique for the assessment of body composition (Fields and Hunter, 2004;Fields et al, 2005).…”