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 (original) (raw)
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Arquivos Brasileiros de Endocrinologia & Metabologia, 2008
Aging involves both nutritional and physiological changes, reducing fat-free mass (FFM) and increasing body fat, both of which are associated with physical weakness, unfitness and morbidity among the elderly. This study was undertaken to analyze the cross-validity of bioelectrical impedance equations for the prediction of fat-free mass (FFM) in elderly Brazilians. A cross-sectional population-based study, was performed in Florianópolis, Santa Catarina, Brazil, 2006. The study sample comprised 60 men and 120 women, aged 60 to 81. The dual energy X-ray absorptiometry (DEXA) served as gold standard. Predicted %BF and FFM were obtained from various anthropometric equations and bioelectric impedance. The cross-validation criteria suggested by Lohman and Bland-Altman plots of differences against the mean were used. The body mass index of the sample ranged from 18.4 to 39.3 kg/m². Mean percent body fat was 23.1 ± 5.8% in men and 37.3 ± 6.9% in women (range: 6 to 51.4%). In men, the equatio...
The journal of nutrition, health & aging, 2012
To compare measures of fat-free mass (FFM) by three different bioelectrical impedance analysis (BIA) devices and to assess the agreement between three different equations validated in older adult and/or overweight populations. Cross-sectional study. Orthopaedics ward of Brisbane public hospital, Australia. Twenty-two overweight, older Australians (72 yr ± 6.4, BMI 34 kg/m² ± 5.5) with knee osteoarthritis. Body composition was measured using three BIA devices: Tanita 300-GS (foot-to-foot), Impedimed DF50 (hand-to-foot) and Impedimed SFB7 (bioelectrical impedance spectroscopy (BIS)). Three equations for predicting FFM were selected based on their ability to be applied to an older adult and/ or overweight population. Impedance values were extracted from the hand-to-foot BIA device and included in the equations to estimate FFM. The mean FFM measured by BIS (57.6 kg ± 9.1) differed significantly from those measured by foot-to-foot (54.6 kg ± 8.7) and hand-to-foot BIA (53.2 kg ± 10.5) (P ...
Journal of Clinical Densitometry, 2009
The purpose of this study was to compare the Rudolph J. Liedtke (RJL) Sciences Quantum II system bioelectrical impedance analyzer (BIA) with the fan beam Hologic dual-energy X-ray absorptiometry (DXA, software V8.26a) for assessing body composition in postmenopausal obese women. Thirty-three postmenopausal overweight/obese females (mean age: 53.9 ± 6.0 yr; mean weight: 91.3 ± 17.5 kg; and mean body mass index [BMI]: 33.1 ± 5.7 kg/m2) were evaluated for comparison of body weight (BW), fat mass (FM), percent FM (%FM), and fat free mass (FFM). The comparison was assessed by RJL Quantum 2 Cyprus 2.6© (Clinton Township, MI) BIA vs fan beam DXA Hologic QDR-4500A software V8.26a (ODR 4500 Hologic, Inc., Waltham, Mass). RJL-BIA and DXA measurements were performed at the same time. BW was measured using a balance scale (Detecto; Web City, MO) and these results were used for the RJL-BIA analysis. Balance weight was compared with DXA BW. Correlations between DXA and RJL-BIA for BW, FM, %FM, and FFM were 0.998, 0.980, 0.782, and 0.926 (p < 0.01), respectively. Bland-Altman plots demonstrated general agreement between methods for BW, FM, %FM, and FFM. However, for the latter 3 metrics of body composition, one unit change using BIA does not correspond to one unit change using DXA, as there were systematic disagreements at either end of the range of values. But RJL-BIA could be a valid method for assessing body composition of overweight/obese postmenopausal women once appropriate validated regression equations have been developed.