Figures
- Fig. 1.—
Intermethod agreement of fat-free mass (FFM) measurement for: a) dual energy X‐ray absorptiometry (DEXA) and bioelectric impedance analysis (BIA) (FFMDEXA - FFMBIA); and b) DEXA and skinfold anthropometry (SFA) (FFMDEXA - FFMSFA). Bland and Altman plots of the differences (Δ) between methods of measuring FFM (▵: females; ▴: males). Mean differences (solid line) and limits of agreement (±2sd; - - -) are shown for the whole population.
- Fig. 2.—
Intermethod agreement of fat-free mass index (FFMI) measurement for: a) dual energy X‐ray absorptiometry (DEXA) and bioelectric impedance analysis (BIA) (FFMIDEXA - FFMIBIA); and b) DEXA and skinfold anthropometry (SFA) (FFMIDEXA - FFMISFA). Bland and Altman plots of the differences (Δ) between methods of measuring FFMI (▵: females; ▴: males). Mean differences (solid line) and limits of agreement (±2sd; - - -) are shown for the whole population.
- Fig. 3.—
Sex differences in body composition measurements for: a) fat-free mass (FFM); and b) FFM index (FFMI) (□: total; ┘: males; └: females). Data are presented as mean±sem intermethod difference (Δ). DEXA: dual energy X‐ray absorptiometry; BIA: bioelectric impedance analysis; SFA: skinfold anthropometry. #: p=0.000; ¶: p=0.042; +: p=0.018.
- Fig. 4.—
Validation of bioelectric impedance analysis as a means of measuring fat-free mass (FFM) against deuterium-dilution (total body water measurement). Data were obtained from a study of 117 chronic obstructive pulmonary disease patients (▪: males; •: females). Sex-specific regression equations for the calculation of FFM from impedance measurements were derived from this study (see Appendix). The regression line for the whole group is shown. (Reproduced with permission from A.M.W. Schols, University of Maastricht, Maastricht, the Netherlands).
Tables
- Table 1—
Baseline patient characteristics
Males Females Subjects n 53 32 Age yrs 67.7±8.4 65.6±8.7 Height m 1.72±0.07 1.59±0.06 Weight kg 70.2±13.0 60.2±10.5 BMI kg·M−2 23.7±3.9 23.7±3.3 FEV1 L 0.91±0.38 0.84±0.36 FVC L 2.56±0.79 1.92±0.53 FEV1 % pred 30.9±12.8 40.6±13.7 -
Data are presented as mean±sd
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BMI: body mass index
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FEV1: forced expiratory volume in one second
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FVC: forced vital capacity
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% pred: percentage of the predicted value
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- Table 2—
Fat-free mass (FFM) and FFM index (FFMI) by dual energy X‐ray absorptiometry (DEXA), bioelectric impedance analysis (BIA) and skinfold anthropometry (SFA)
Males Females DEXA FFM kg 50.6±7.6 36.4±5.0 FFMI kg·m−2 17.0±1.9 14.4±1.4 Depletion % 36 72 BIA FFM kg 48.8±6.4 37.5±4.6 FFMI kg·m−2 16.5±2.0 14.8±1.3 Depletion % 42 59 SFA FFM kg 51.7±6.9 39.1±5.0 FFMI kg·m−2 17.4±1.8 15.4±1.4 Depletion % 28 53 -
Data are presented as mean±sd
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Patients were considered nutritionally depleted if they had a body mass index of ≤21 or an FFMI of ≤15 (females) or ≤16 (males)
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- Table 3—
Reproducibility of fat-free mass (FFM) measurements
Patient characteristics Mean difference* sd# p‐value ICC Weight kg 0.43 0.97 0.035 0.997 FFMDEXA kg −0.17 1.39 0.54 0.991 FFMBIA kg −0.20 1.37 0.48 0.987 FFMSFA kg 0.02 1.29 0.93 0.99 -
*: calculated by subtracting the first measurement from a second taken 7 weeks later
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#: of mean difference
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Significance was tested using paired t‐tests
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ICC: intraclass correlation coefficient
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DEXA: dual energy X‐ray absorptiometry
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BIA: bioelectric impedance analysis
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SFA: skinfield anthropometry
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