The prediction of total body water from bioelectrical impedance in patients with anorexia nervosa

Scalfi, Luca; Bedogni, Giorgio; Marra, Maurizio; Biase, Giuseppe Di; Caldara, A.; Severi, S; Contaldo, Franco; Battistini, N.

doi:10.1079/bjn19970156

Cited by 25 publications

(29 citation statements)

References 22 publications

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“…Besides the larger number of subjects, it is likely that the greater interindividual variability in TBW : Wt observed in the present study has contributed to this result (Scalfi et al, 1997). Not unexpectedly , the RMSE% associated with the cross-validation of the ECW equation was higher than that associated with the TBW equation (8 vs 5%).…”

Section: Discussionmentioning

confidence: 45%

“…We have the policy of systematically testing this hypothesis in our BIA studies. For instance, we have not been able to show that four-polar BIA at 50 kHz is more accurate than Wt in estimating TBW and appendicular body composition in anorexic women (Scalfi et al, 1997;Bedogni et al, 2003b). Even if the use of multifrequency instruments may change this evidence, the use of an impedance-meter is clearly not justified in these circumstances.…”

Section: Discussionmentioning

confidence: 73%

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

et al. 2004

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Objective: To measure body water distribution and to evaluate the accuracy of eight-polar bioelectrical impedance analysis (BIA) for the assessment of total body water (TBW) and extracellular water (ECW) in severe obesity. Design: Cross-sectional study. Setting: Obesity clinic. Subjects: In all, 75 women aged 18-66 y, 25 with body mass index (BMI) between 19.1 and 29.9 kg/m 2 (ie not obese), 25 with BMI between 30.0 and 39.9 kg/m 2 (ie class I and II obese), and 25 with BMI between 40.0 and 48.2 kg/m 2 (ie class III obese). Methods: TBW and ECW were measured by 2 H 2 O and Br dilution. Body resistance (R) was obtained by summing the resistances of arms, trunk and legs as measured by eight-polar BIA (InBody 3.0, Biospace, Seoul, Korea). The resistance index at a frequency of x kHz (RI x ) was calculated as height 2 /R x . Results: ECW : TBW was similar in women with class III (4673%, mean7s.d.) and class I-II obesity (4573%) but higher than in nonobese women (3973%, Po0.05). In a random subsample of 37 subjects, RI 500 explained 82% of TBW variance (Po0.0001) and cross-validation of the obtained algorithm in the remaining 38 subjects gave a percent root mean square error (RMSE%) of 5% and a pure error (PE) of 2.1 l. In the same subjects, RI 5 explained 87% of ECW variance (Po0.0001) and cross-validation of the obtained algorithm gave a RMSE% of 8% and a PE of 1.4 l. The contribution of weight and BMI to the prediction of TBW and ECW was nil or negligible on practical grounds. Conclusions: ECW : TBW is similar in women with class I-II and class III obesity up to BMI values of 48.2 kg/m 2 . Eight-polar BIA offers accurate estimates of TBW and ECW in women with a wide range of BMI (19.1-48.2 kg/m 2 ) without the need of population-specific formulae. Sponsorship: Progetti di Ricerca Corrente, Istituto Auxologico Italiano.

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Section: Discussionmentioning

confidence: 45%

Section: Discussionmentioning

confidence: 73%

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

et al. 2004

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“…In homogeneous samples such as those studied here, Wt is generally a better predictor of TBW and FFM than Rl, while the contrary happens for heterogeneous samples (Kushner et al, 1992;Scalfi et al, 1997). The reason why Wt did contribute to the unexplained variance of FFM in anorexics but not in controls is unclear but it is possible that a frequency of 50 kHz may not be enough to obtain an accurate estimate of FFM in anorexics because of changes in their ECW: ICW ratio.…”

Section: Discussionmentioning

confidence: 54%

“…BIA offers accurate estimates of total body composition in anorexics, but its accuracy for the assessment of appendicular body composition in these subjects is not known (Hannan et al, 1990;Scalfi et al, 1993Scalfi et al, , 1997Polito et al, 1998). In the present study, population-specific equations were needed to obtain accurate estimates of total and appendicular FFM from BIA in anorexics.…”

Section: Discussionmentioning

confidence: 99%

Comparison of bioelectrical impedance analysis and dual-energy X-ray absorptiometry for the assessment of appendicular body composition in anorexic women

et al. 2003

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Objective: To establish the accuracy of bioelectrical impedance analysis (BIA) for the assessment of appendicular body composition in anorexic women. Design: Cross-sectional study. Setting: Outpatient University Clinic. Subjects: A total of 39 anorexic and 25 control women with a mean (s.d.) age of 21 (3) y. Methods: Total, arm and leg fat-free mass (FFM) were measured by dual-energy X-ray absorptiometry and predicted from total and segmental BIA at 50 kHz. The predictor variable was the resistance index (Rl), that is, the ratio of height 2 to body resistance for the whole body and the ratio of length 2 /limb resistance for the arm and leg. Results: Predictive equations developed on controls overestimated total, arm and leg FFM in anorexics (Po0.0001). Populationspecific equations gave a satisfactory estimate of total and appendicular FFM in anorexics (P ¼ NS) but had higher percent root mean square errors (RMSEs%) as compared to those developed on controls (8% vs 5% for whole body, 12% vs 10% for arm and 10% vs 8% for leg). The accuracy of the estimate of total and leg FFM in anorexics was improved by adding body weight (Wt) as a predictor with Rl (RMSE% ¼ 5% vs 8% and 7% vs 10%, respectively). However, the same accuracy was obtained using Wt alone, suggesting that in anorexics, BIA at 50 kHz is not superior to Wt for assessing total and leg FFM. Conclusion: BIA shows some potential for the assessment of appendicular body composition in anorexic women. However, Wt is preferable to BIA at 50 kHz on practical grounds. Further studies should consider whether frequencies 450 kHz give better estimates of appendicular composition in anorexics as compared to Wt.

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“…It functions as a structural component, a medium for chemical reactions and a vehicle for interchange between the body cells and organs. It has been suggested that body water as percent of body weight increases in anorexia (Dempsey et al, 1984;Scal® et al, 1997), and it has been found to be irregularly distributed with expansion of the extracellular compartment at the expense of the intracellular (Veisman et al, 1988;Scal® et al, 1993). To estimate total body water we have used the Kushner's equation (1992) that has been validated also in anorexic patients (Scal® et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

Body composition changes in anorexia nervosa

Polito¹,

Cuzzolaro

Raguzzini³

et al. 1998

Eur J Clin Nutr

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Objective: To assess the body composition changes in anorexia nervosa and after medium term recovery. Design: A descriptive study. Setting: Rome, Italy. Subjects: Twenty women affected by anorexia nervosa (AN) with a BMI [weight (kg)aheight (m 2 )] below 17 kgam 2 and weight-stable for at least three months, were compared with 10 well nourished control women (CO) and nine rehabilitated subjects (R-AN), who had a BMI above 18.5 kgam 2 stable for at least the last six months. Interventions: Body fat was assessed by underwater weighing, muscle mass by urinary creatinine, total body water (TBW) by impedance parameters (50 kHz and 800 mA), skeletal mass by anthropometry and radius bone mineral density by dual photon absorptiometry in ultra-distal (UD-BMD) and medio-distal (MD-BMD) sites. Results: The AN group, as compared to the control group, had a signi®cantly lower weight, body mass index (BMI kgam 2 ) and percent body fat (P`0.0000). Creatinine urinary excretion was lowest in absolute term and when expressed as creatinine height index or per kg fat free mass (FFM) (P`0.0000); muscle mass per kg body weight was 13% lower (P`0.01). Ultra distal bone mineral density (UD-BMD) was 6% lower (not signi®cant). TBW as percent of body weight was signi®cant higher (P`0.001): however TBWaFFM % was not statistically different with large inter-individual variability. An altered distribution of extra and intra-cellular water was suggested by the phase angle (AN: 4.4 AE 0.8 ; CO: 6.1 AE 0.4 ; (P`0.0000). In rehabilitated anorexic patients (R-AN) the fat mass represented 53% of the weight gain. Their creatinine excretion remained still below the mean value of the controls (P`0.001). The impedance parameters were not signi®cantly different between the R-AN and the CO groups, however, the phase angle of the R-AN (5.0 AE 0.7 ) remained lower than in the CO group, indicating that the water distribution was still altered. Conclusions: This study shows that AN is a condition of reduced body fat as well as of muscle mass, with a slightly reduced bone mass. In the course of rehabilitation, most of the weight regained is represented by fat, while the muscle mass appears to lag behind, at least in the medium term.

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The prediction of total body water from bioelectrical impedance in patients with anorexia nervosa

Cited by 25 publications

References 22 publications

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

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

Comparison of bioelectrical impedance analysis and dual-energy X-ray absorptiometry for the assessment of appendicular body composition in anorexic women

Body composition changes in anorexia nervosa

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