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Bias between two reference methods of body composition assessment in elderly men
The aim of this study was to compare BISA to single frequency (50KHz) BIA and DEXA for body composition assessment, initially in ‘healthy volunteers’. The LBM and FM of 9 volunteers were assessed by DEXA (Norland XR 26 Mk II), immediately followed by BISA (Xitron 4000) over a frequency range of 5-1000 KHz, including 50 KHz. Precision of the bioimpedance was generally very good throughout the frequency range (CV of repeated measurements using the same electrodes was less than 0.3%). Estimates of LBM by BISA correlated better with DEXA than did single frequency BIA (r = 0.989 and 0.978 respectively). This was also the case for FM (r =0.975 and 0.747). Multi-frequency BIA seems, therefore, to have advantages over single frequency analysis and would merit further study.
and NaBr dilution in 39 COPD patients (246, age: 65 f 9y, FEV,: 38 f 14%). Respiratory muscle strength was measured by maximal inspiratory mouth pressure and exercise capacity (n = 23, 166) by incremental cycle ergometry (max. load cycled: W,,,. max. oxygen consumption: VO*). Fat-free mass (FFM = TBW/0.73) and FFM-index (FFMI = FFM/height’) and intracellular water (ICW) were calculated. Results: mean (SD)
Underweight patients had a significantly lower TBW and FM than normal weight patients, but exhibited no significant difference in body water compartments. Independent of the FEV,, FFMI correlated highly significant and better than the BMI with W,,, (r = 0.82”’ vs r = 0.58**), VOZ_max(r = 0.81*** vs r = 0.68*“) and respiratory muscle strength (r = 0.59”’ vs 0.38). Conclusions: Tissue depletion in clinically stable COPD-patients is reflected in a low BMI, a low FFMI and a lower albumine concentration, but not in shifts of body-water compartments. The FFMI is an important determinant of physiological function in these patients.
P.25 Bias between two reference methods of body composition assessment in elderly men. N. J. Fuller, M. B. Sawyer, M. A. Laskey, f. faxton’ and M. Elia. MRC Dunn Clinical Nutrition Practice, Cambridge, UK.
Centre and ‘Lensfield
Medical
This study aimed to establish extent of agreement between two body composition reference methods, dual-energy X-ray absorptiometry (DEXA - Lunar Model DPX) and deuterium dilution (D,O) space (assuming that D20 space is 1.04 total body water (TBW) space and that there is 72% hydration of fat-free mass - FFM), in 15 elderly men, selected randomly from the populaticn, with the following characteristics: mean age 82 (76-87) years; body mass index 24.4 (SD 3.0) kg/m’; TBW 36.0 (SD 4.8) kg or 50.4 (SD 3.1) % weight (D,O); body fat 29.9 (SD 4.3) % body weight (D,O); and bone mineral content 2.9 (SD 0.3) kg (DEXA). Bias and 95% limits of agreement were assessed (D20 minus DEXA). The bias and 95% limits of agreement for FFM were found to be -4.08 kg and 3.13 kg, and for fat (% body weight) 5.79% and 4.09 (%), respectively. No association was found between measurement magnitude and difference between methods. These findings contrast those (smaller bias, larger 95% limits of agreement) in younger men (Fuller et al. 1992). The magnitude of bias, which may originate from either age-related changes in hydration of FFM or from technical difficulties incorrectly interpreting DEXA measurements (e.g. field depth differences), is of major concern and suggests the need for revision of assumptions or practices applied to the elderly. Reference: Fuller N.J., Jebb S.A., Laskey M.A. et al. Clinical Science 1992; 82: 687-693.
P.27 Is anthropometry a satisfactory measure of fat-free mass in HIV-infected individuals? D. Sharpstone,H. Ross, C. Murray, M. Hancock, M. Phelan and 8. Gazzard. Chelsea and Westminster Hospital, London, UK. Introduction: Controversy exists over the most suitable method for assessing fat-free mass in HIV-positive individuals. Dualenergy X-ray absorptiometry (DEXA) is widely recognised as an accurate measure of body composition but is not widely available. Anthropometry, bioelectrical impedance (Bl) and 24 hour urine creatinine are widely available but considered to be less accurate. Aim: To correlate 3 measures of body composition with DEXA in HIV-infection. Methods: Ninety-five HIV-positive people (non-AIDS) with CD4 counts of less than 400 were recruited. Fat-free mass was assessed using DEXA and anthropometry at 4 sites. BI was assessed using the Bodystat 500 (Akerne Instruments). A 24 hour urine creatinine was collected as a measure of muscle mass. Coefficients of correlation were derived for all techniques. Results: Anthropometry (Height)‘/Bl 24 hour urine creatinine
Anthropometry
(Height)%1
0.65 0.42
0.14
Conclusion: Anthropometry and DEXA are closely correlated. If we accept DEXA to be an accurate measure of fat-free mass, as shown in other studies, then anthropometry is a useful technique for assessing fat-free mass in these patients. BI is less closely correlated with DEXA than anthropometry. 24 hour urinary creatinine offers no advantage over anthropometry or BI.
P.26 Analysis of body composition in relation to tissue depletion and physiological function in clinically stable patients with chronic obstructive pulmonary disease. E. M. Baarends,A. M. W. J. Schols, Ft. Mostert’ and E. F. M. Wouters. Dept of Pulmonology, University of Limburg, Maastricht, Netherlands; ‘Asthma Centre Hornerheide, Horn, Netherlands.
DEXA 0.92 0.71 0.45
P.28 The influence of an acute disease exacerbation on the metabolic profile of patients with chronic obstructive pulmonary disease. M. A. P. Vermeeren’,A. M. W. J. Schols, F. C. M. Qaudvlieg
The The
Introduction: Weight loss is a common feature in patients with Chronic Obstructive Pulmonary Disease (COPD). The purpose of this study was to examine body composition in COPD patients in relation to tissue depletion and physiological function. Methods: Total body water (TBW) and extracellular water (ECW) (corrected bromide space (CBS)) were measured by deuterium
and E. F. M. l$‘outers. Depts of Pulmonology and Maastricht, The Netherlands.
‘Dietetics, University Hospital
Introduction: Nutritional depletion commonly occurs in chronic obstructive pulmonary disease (COPD). In this study we investi38
and NaBr dilution in 39 COPD patients (246, age: 65 f 9y, FEV,: 38 f 14%). Respiratory muscle strength was measured by maximal inspiratory mouth pressure and exercise capacity (n = 23, 166) by incremental cycle ergometry (max. load cycled: W,,,. max. oxygen consumption: VO*). Fat-free mass (FFM = TBW/0.73) and FFM-index (FFMI = FFM/height’) and intracellular water (ICW) were calculated. Results: mean (SD)
Underweight patients had a significantly lower TBW and FM than normal weight patients, but exhibited no significant difference in body water compartments. Independent of the FEV,, FFMI correlated highly significant and better than the BMI with W,,, (r = 0.82”’ vs r = 0.58**), VOZ_max(r = 0.81*** vs r = 0.68*“) and respiratory muscle strength (r = 0.59”’ vs 0.38). Conclusions: Tissue depletion in clinically stable COPD-patients is reflected in a low BMI, a low FFMI and a lower albumine concentration, but not in shifts of body-water compartments. The FFMI is an important determinant of physiological function in these patients.
P.25 Bias between two reference methods of body composition assessment in elderly men. N. J. Fuller, M. B. Sawyer, M. A. Laskey, f. faxton’ and M. Elia. MRC Dunn Clinical Nutrition Practice, Cambridge, UK.
Centre and ‘Lensfield
Medical
This study aimed to establish extent of agreement between two body composition reference methods, dual-energy X-ray absorptiometry (DEXA - Lunar Model DPX) and deuterium dilution (D,O) space (assuming that D20 space is 1.04 total body water (TBW) space and that there is 72% hydration of fat-free mass - FFM), in 15 elderly men, selected randomly from the populaticn, with the following characteristics: mean age 82 (76-87) years; body mass index 24.4 (SD 3.0) kg/m’; TBW 36.0 (SD 4.8) kg or 50.4 (SD 3.1) % weight (D,O); body fat 29.9 (SD 4.3) % body weight (D,O); and bone mineral content 2.9 (SD 0.3) kg (DEXA). Bias and 95% limits of agreement were assessed (D20 minus DEXA). The bias and 95% limits of agreement for FFM were found to be -4.08 kg and 3.13 kg, and for fat (% body weight) 5.79% and 4.09 (%), respectively. No association was found between measurement magnitude and difference between methods. These findings contrast those (smaller bias, larger 95% limits of agreement) in younger men (Fuller et al. 1992). The magnitude of bias, which may originate from either age-related changes in hydration of FFM or from technical difficulties incorrectly interpreting DEXA measurements (e.g. field depth differences), is of major concern and suggests the need for revision of assumptions or practices applied to the elderly. Reference: Fuller N.J., Jebb S.A., Laskey M.A. et al. Clinical Science 1992; 82: 687-693.
P.27 Is anthropometry a satisfactory measure of fat-free mass in HIV-infected individuals? D. Sharpstone,H. Ross, C. Murray, M. Hancock, M. Phelan and 8. Gazzard. Chelsea and Westminster Hospital, London, UK. Introduction: Controversy exists over the most suitable method for assessing fat-free mass in HIV-positive individuals. Dualenergy X-ray absorptiometry (DEXA) is widely recognised as an accurate measure of body composition but is not widely available. Anthropometry, bioelectrical impedance (Bl) and 24 hour urine creatinine are widely available but considered to be less accurate. Aim: To correlate 3 measures of body composition with DEXA in HIV-infection. Methods: Ninety-five HIV-positive people (non-AIDS) with CD4 counts of less than 400 were recruited. Fat-free mass was assessed using DEXA and anthropometry at 4 sites. BI was assessed using the Bodystat 500 (Akerne Instruments). A 24 hour urine creatinine was collected as a measure of muscle mass. Coefficients of correlation were derived for all techniques. Results: Anthropometry (Height)‘/Bl 24 hour urine creatinine
Anthropometry
(Height)%1
0.65 0.42
0.14
Conclusion: Anthropometry and DEXA are closely correlated. If we accept DEXA to be an accurate measure of fat-free mass, as shown in other studies, then anthropometry is a useful technique for assessing fat-free mass in these patients. BI is less closely correlated with DEXA than anthropometry. 24 hour urinary creatinine offers no advantage over anthropometry or BI.
P.26 Analysis of body composition in relation to tissue depletion and physiological function in clinically stable patients with chronic obstructive pulmonary disease. E. M. Baarends,A. M. W. J. Schols, Ft. Mostert’ and E. F. M. Wouters. Dept of Pulmonology, University of Limburg, Maastricht, Netherlands; ‘Asthma Centre Hornerheide, Horn, Netherlands.
DEXA 0.92 0.71 0.45
P.28 The influence of an acute disease exacerbation on the metabolic profile of patients with chronic obstructive pulmonary disease. M. A. P. Vermeeren’,A. M. W. J. Schols, F. C. M. Qaudvlieg
The The
Introduction: Weight loss is a common feature in patients with Chronic Obstructive Pulmonary Disease (COPD). The purpose of this study was to examine body composition in COPD patients in relation to tissue depletion and physiological function. Methods: Total body water (TBW) and extracellular water (ECW) (corrected bromide space (CBS)) were measured by deuterium
and E. F. M. l$‘outers. Depts of Pulmonology and Maastricht, The Netherlands.
‘Dietetics, University Hospital
Introduction: Nutritional depletion commonly occurs in chronic obstructive pulmonary disease (COPD). In this study we investi38