Four-Component Model of Body Composition in Chronic Renal Failure Comprising Dual-Energy X-ray Absorptiometry and Measurement of Total Body Water by Deuterium Oxide Dilution

1996 ◽  
Vol 91 (6) ◽  
pp. 763-769 ◽  
Author(s):  
Graham Woodrow ◽  
Brian Oldroyd ◽  
John H. Turney ◽  
Peter S. W. Davies ◽  
Janice M. E. Day ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Total Body Water ◽  
Dual Energy ◽  
Body Water ◽  
Fat Free Mass ◽  
Component Model ◽  
X Ray ◽  
Four Component Model ◽  
Total Body

1. Assessment of nutrition in patients with chronic renal failure by body composition measurement techniques may be affected by variable hydration. 2. This study aimed to derive a four-component model of body composition (consisting of fat, protein, total body water and body mineral) from a combination of dual-energy X-ray absorptiometry and total body water measured by deuterium oxide dilution, allowing assessment of body protein stores without the effect of variation in hydration. Patients with chronic renal failure on haemodialysis, peritoneal dialysis and conservative treatment and a control group were studied. Patients with chronic renal failure were at an ‘ideal’ state of hydration on clinical assessment. 3. Hydration was defined by total body water as a percentage of fat-free mass measured by dual-energy X-ray absorptiometry, and no differences were found between chronic renal failure subgroups and control subjects (except in the female undialysed chronic renal failure subgroup). Hydration was significantly correlated with percentage total body fat in the control groups but not in patients with chronic renal failure. 4. Lean tissue measured by dual-energy X-ray absorptiometry was significantly reduced in three of the six chronic renal failure groups compared with control subjects (male and female patients on haemodialysis and female patients on peritoneal dialysis). Protein estimated from the four-component model failed to detect these abnormalities. 5. Lean tissue measured by dual-energy X-ray absorptiometry in normal subjects strongly correlated with fat-free mass measured by total body potassium in normal subjects (male r = 0.91; female r = 0.89, both P < 0.0001). The correlation of protein estimated from the four-component model with fat-free mass measured by total body potassium was far weaker in male control subjects (r = 0.51, P < 0.05) and not significant in female control subjects (r = 0.38, P not significant). In the normal subjects protein estimated from the four-component model showed a much greater variation from protein estimated by total body potassium than did protein estimated simply as 27% of dual-energy X-ray absorptiometry fat-free mass minus total body mineral. 6. Hydration in patients with chronic renal failure in whom fluid balance is believed to be normal on clinical criteria does not differ from that in normal subjects. The combined model of dual-energy X-ray absorptiometry and total body water is not a useful method for the measurement of body protein.

QDR 4500A DXA overestimates fat-free mass compared with criterion methods

2003 ◽  
Vol 94 (3) ◽  
pp. 959-965 ◽  
Author(s):  
Frances Tylavsky ◽  
Timothy Lohman ◽  
Barbara A. Blunt ◽  
Dale A. Schoeller ◽  
Thomas Fuerst ◽  
...  
Keyword(s):  
Lower Estimate ◽  
Dual Energy ◽  
Fat Free Mass ◽  
Component Model ◽  
Men And Women ◽  
Hydration Level ◽  
X Ray ◽  
Beam System ◽  
Four Component Model ◽  
Total Body

This study evaluated the accuracy with which the dual-energy X-ray absorptiometer (Hologic QDR 4500A) measured fat-free mass (FFM), fat mass (FM), and hydration of FFM. In a study of 58 men and women (ages 70–79 yr), the QDR 4500A was found to provide a systematically higher estimate of FFM and lower estimate of FM than a four-component model of body composition. A correction factor from this study was developed and applied to two other samples ( n = 13 and 37). We found mean corrected levels of FFM and FM to be equivalent to that obtained by the four-component model or total body water. In addition, the hydration of the corrected FFM was closer to the established hydration level in adult samples and that obtained from the four-component model. These findings suggest that the current calibration of the fan-beam system of the Hologic QDR 4500A provides an overestimate of FFM and underestimate of FM compared with reference methods.

scholarly journals Evaluation of a model for total body protein mass based on dual-energy X-ray absorptiometry: comparison with a reference four-component model

2001 ◽  
Vol 86 (1) ◽  
pp. 45-52 ◽  
Author(s):  
N. J. Fuller ◽  
J. C. K. Wells ◽  
M. Elia
Keyword(s):  
Dual Energy ◽  
Fat Free Mass ◽  
Component Model ◽  
Body Volume ◽  
Body Protein ◽  
X Ray ◽  
Protein Mass ◽  
Four Component Model ◽  
The Mean ◽  
Total Body

The aim of the present study was to evaluate a model of body composition for assessing total body protein (TBP) mass using dual-energy X-ray absorptiometry (DXA), with either measured or assumed total body water (TBW); it was intended to provide a less complex or demanding alternative technique to, for example, the four-component model (4-CM). The following measurements were obtained in healthy adults (n46) aged 18–62 years, and children (n30) aged 8–12 years: body weight (BWt), body volume (BV; under-water weighing), TBW (2H-dilution space or predicted using an assumed hydration fraction of fat-free mass (HFffm)), bone mineral content (BMC; DXA) and fat-free soft tissue (FFST; DXA). TBP was calculated using the 4-CM (TBP=3·050BWt-0·290TBW-2·734BMC-2·747BV) and the DXA model (TBP=FFST-0·2305BMC-TBW). DXA measurements were obtained using the Lunar DPX (Lunar Radiation Corporation, Madison, WI, USA) or Hologic QDR 1000/W (Hologic, Waltham, MA, USA). Precision of the DXA model for TBP with measured TBW (4·6–6·8 % mean TBP) was slightly worse than the 4-CM (4·0–5·4 %), whereas that modelled with assumed HFffmwas more precise (2·4–5·2 %) because it obviated imprecision associated with measuring TBW. Agreement between the 4-CM and DXA model with measured TBW was also worse (e.g. bias, 15 % of the mean; 95 % limits of agreement up to ±39 % for adults measured on the Lunar DPX) than when a constant for HFffmwas assumed (3·7 % and ±21 % respectively). Most of the variability in agreement between these various models was due to interpretation of biological factors, rather than to measurement imprecision. Therefore, the DXA model, which is less complex and demanding than the 4-CM, is of value for assessing TBP in groups of healthy subjects, but is of less value for individuals in whom there may be substantial differences from reference 4-CM estimates.

Fat-Free Mass and Percent Body Fat Assessments by Dual-Energy X-ray Absorptiometry, Densitometry and Total Body Water

1993 ◽  
pp. 71-74
Author(s):  
Rita Wellens ◽  
Alex F. Roche ◽  
Shumei Guo ◽  
William C. Chumlea ◽  
Roger M. Siervogel
Keyword(s):  
Body Fat ◽  
Total Body Water ◽  
Dual Energy ◽  
Body Water ◽  
Fat Free Mass ◽  
Percent Body Fat ◽  
X Ray ◽  
Total Body

Four-component model for the assessment of body composition in humans: comparison with alternative methods, and evaluation of the density and hydration of fat-free mass

1992 ◽  
Vol 82 (6) ◽  
pp. 687-693 ◽  
Author(s):  
N. J. Fuller ◽  
S. A. Jebb ◽  
M. A. Laskey ◽  
W. A. Coward ◽  
M. Elia
Keyword(s):  
Body Composition ◽  
Skinfold Thickness ◽  
Dual Energy ◽  
Fat Free Mass ◽  
Component Model ◽  
Alternative Methods ◽  
X Ray ◽  
Four Component Model ◽  
Deuterium Dilution ◽  
Component Models

1. Body composition was assessed in 28 healthy subjects (body mass index 20–28 kg/m2) by dual-energy X-ray absorptiometry, deuterium dilution, densitometry, 40K counting and four prediction methods (skinfold thickness, bioelectrical impedance, near-i.r. interactance and body mass index). Three- and four-component models of body composition were constructed from combinations of the reference methods. The results of all methods were compared. Precision was evaluated by analysis of propagation of errors. The density and hydration fraction of the fat-free mass were determined. 2. From the precision of the basic measurements, the propagation of errors for the estimation of fat (± sd) by the four-component model was found to be ± 0.54 kg, by the three-component model, ± 0.49 kg, by deuterium dilution, ± 0.62 kg, and by densitometry, ± 0.78 kg. Precision for the measurement of the density and hydration fraction of fat-free mass was ± 0.0020 kg/l and ± 0.0066, respectively. 3. The agreement between reference methods was generally better than between reference and alternative methods. Dual-energy X-ray absoptiometry predicted three- and four-component model body composition slightly less well than densitometry or deuterium dilution (both of which greatly influence these multi-component models). 4. The hydration fraction of fat-free mass was calculated to be 0.7382 ± 0.0213 (range 0.6941–0.7837) and the density of fat-free mass was 1.1015 ± 0.0073 kg/1 (range 1.0795–1.1110 kg/1), with no significant difference between men and women for either. 5. The results suggest that the three- and four-component models are not compromised by errors arising from individual techniques. Dual-energy X-ray absorptiometry would appear to be a suitable alternative method for the assessment of body composition in these healthy adults. The traditional mean value assumed for density of the fat-free mass in classic densitometry (1.1 kg/l) appears to be appropriate, and the mean hydration fraction was close to values which are generally applied to the fat-free mass (0.72–0.73). Despite concealing considerable inter-individual variation, these mean values may be applied to groups with characteristics similar to those in this study. Finally, with the notable exception of skinfold thickness, bedside prediction methods show poor agreement with both the three- and the four-component models.

226 BODY COMPOSITION BY HYDRODENSITOMETRY, DUAL ENERGY X-RAY ABSORPTIOMETRY AND TOTAL BODY WATER IN ADULTS

1994 ◽  
Vol 26 (Supplement) ◽  
pp. S40
Author(s):  
R. Wellens ◽  
A. F. Roche ◽  
H. Khamis ◽  
S. Guo ◽  
W. C. Chumlea ◽  
...  
Keyword(s):  
Body Composition ◽  
Total Body Water ◽  
Dual Energy ◽  
Body Water ◽  
X Ray ◽  
Total Body

scholarly journals Change of Body Impedance according to Loss of Total Body Water during Hemodialysis in Chronic Renal Failure Patients

1996 ◽  
Vol 30 (5) ◽  
pp. 566
Author(s):  
Kyung Bong Yoon ◽  
Kwang Ho Lee ◽  
Jung Won Lee ◽  
Dae Ja Um ◽  
Ryung Choi ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Total Body Water ◽  
Body Water ◽  
Body Impedance ◽  
Total Body
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