Comparison of Whole Body and Segmental Bioimpedance Methodologies for Estimating Total Body Water (original) (raw)
Related papers
Acta Diabetologica, 2003
Bioelectric impedance analysis (BIA) is commonly used in clinical settings and field studies for estimating total, extracellular, and intracellular water compartments. The objective of the present study was to carry out a meta-analysis of published reports in which total body water (TBW) was estimated using BIA techniques and comparisons were made with reference values. We identified 16 reports conducted among healthy and obese adults and individuals with chronic renal failure. Based on the weighted mean difference, we found that those studies using only multi-frequency BIA did not significantly overestimate the TBW compared with the reference values. Thus, among BIA techniques, multi-frequency BIA seems to be a more accurate method for estimating the TBW compartment for healthy and obese adults and for those with chronic renal failure.
British Journal of Nutrition, 2004
The present study was performed to determine how equilibrated fluctuations in hydration affected the validity of bioelectrical impedance analysis (BIA) for body composition assessment. Total body water (TBW) expansion was induced by a 4 d endurance trial and the subsequent water loss was obtained over the recovery period. Twelve healthy men exercised on a cycle and treadmill alternately for 5 h/d over 4 d at moderate intensity. TBW, fat mass (FM) and fat-free mass (FFM) were assessed 3 d before the trial (control), and on the first and eighth day of recovery (R1 and R8 respectively). TBW was evaluated by 2 H dilution (TBW 2H ) as a reference method and by BIA (TBW BIA ) at 100 kHz at the same time. TBW 2H increased significantly between the control day and R1 by 1·87 (SD 1·11) litres (P¼ 0·005) and TBW BIA by 1·38 (SD 1·56) litres (P¼0·009). Both values returned to the control level on R8. For each period, TBW 2H and TBW BIA did not differ significantly and were correlated (r 2 0·85, P¼0·0004 for the control day; r 2 0·63, P¼ 0·03 for R1; r 2 0·75, P¼0·02 for R8). Plasma Na concentration and osmolality did not differ between the control day, R1 and R8. FFM gain (1208 (SD 1983) g) and FM loss (21168 (SD 906) g) between the control day and R1 were followed by a FFM decrease (2624 (SD 1281) g) and a FM increase (860 (SD 1212) g) between R1 and R8. As expected, these FFM and FM changes were significantly correlated with TBW variations. The present results provide evidence that BIA may be a useful method for estimating TBW when fluid shifts are equilibrated and electrolyte concentrations are unchanged. However, it is not a valid technique for assessing FM and FFM under these conditions.
Assessment of foot-to-foot bioelectrical impedance analysis for the prediction of total body water
European Journal of Clinical Nutrition, 1998
Objective: To investigate the accuracy of foot-to-foot impedance methodology for the prediction of total body water and whether leg length rather than stature should be used in the prediction of total body water. Design: Cross-sectional study using volunteers from the community. Setting: University laboratory. Subjects: 57 subjects (29 male; 28 female) aged 19±56 y. Interventions: Total body water was measured using a deuterium oxide dilution technique. Total body water was also predicted using foot-to-foot impedance apparatus (Tanita Inc, Tokyo, Japan, Model TBF 305). Results: Mean values for predicted and measured total body water differed by 0.7 l. However this bias was not constant across all individuals with a progressive underestimation of total body water by foot-to-foot impedance technology as the water content of the body increases. Also the use of leg length did not improve the accuracy of the prediction equation. Conclusions: At the population level predictions of total body water obtained from foot-to-foot impedance technology compare well with measured total body water. However the signi®cant correlation between the difference between predicted and measured total body water and the absolute value for total body water is a concern especially if the technology is used for body composition assessment during a weight loss program. Sponsorship: RJH was in receipt of a Queensland University of Technology Vacation Scholarship.
Metabolites
Bioelectrical impedance analysis (BIA) has proven to be particularly useful due to its inexpensive and rapid assessment of total body water and body density. However, recent fluid intake may confound BIA results since equilibration of fluid between intra- and extracellular spaces may take several hours and furthermore, ingested fluids may not be fully absorbed. Therefore, we aimed to evaluate the impact of different fluid compositions on the BIA. A total of eighteen healthy individuals (10 females, mean ± SD age of 23.1 ± 1.8 years) performed a baseline measurement of body composition before they consumed isotonic 0.9% sodium-chloride (ISO), 5% glucose (GLU) or Ringer (RIN) solutions. During the visit of the control arm (CON), no fluid was consumed. Further impedance analyses were conducted every 10 min after the fluid consumption for 120 min. We found statistically significant interactions between the effects of solution ingestion and time for intra- (ICW, p < 0.01) and extracel...
Enhancing the accuracy of bio impedance analysis in assessing total body water
Objective: To assess the validity of a bio impedance analysis (BIA) instrument in predicting total body water (TBW), assessing the suitability of existing TBW equations and to develop a population specific impedance-based equation for the prediction of TBW in post pubertal adolescent girls using deuterium dilution as the reference method. Methods: The study population comprised of 15 to 19-year-old, Sri Lankan adolescent girls. Body composition was assessed by Fourier transform infrared spectrometry (FTIR) and bio impedance analysis (BIA). Available TBW equations for adolescents were assessed for validity of use on Sri Lankan adolescent girls. A new equation for TBW was derived and validated by linear regression analysis, against TBW derived by FTIR. Results: TBW obtained directly by the BIA instrument as well as TBW calculated using existing equations significantly (P<0.001) underestimated the actual TBW volume, obtained by the reference method (FTIR). Impedance index (height 2 / resistance; cm 2 /Ω) was a significant determinant of TBW in the new TBW equation derived for adolescent girls (TBW = 3.94 + 0.652* impedance index). Discussion: Direct use of the TBW value obtained by the BIA instrument as well as existing impedancebased equations for the prediction of TBW are unsuitable for this population. The new equation utilizing the impedance index, is appropriate for prediction of TBW in Sri Lankan post-pubertal adolescent girls and those of Asian origin, and can be utilized to assess other body composition parameters in this population.
European Journal of Clinical Nutrition, 2012
BACKGROUND/OBJECTIVES: In this study, we aimed to validate the accuracy of single-frequency bioelectrical impedance analysis (SF-BIA) at 50 kHz to assess total body water (TBW) against the reference technique deuterium dilution (D 2 O) and to explore if the simple clinical parameters extracellular fluid (ECF) composition and body shape explain individual differences between D 2 O and SF-BIA (Diff BIA À D2O). SUBJECTS/METHODS: We assessed TBW with D 2 O and SF-BIA in 26 women and 26 men without known disease or anomalous body shapes. In addition, we measured body shape with anthropometry and ECF composition (osmolality, albumin, glucose, urea, creatinine, sodium and potassium). RESULTS: On group average, SF-BIA to predict TBW agreed well with D 2 O (SF-BIA, 39.8 ± 10.1 l; D 2 O, 40.4 ± 10.2 l; and Diff BIA À D2O À 0.7 l). In four individuals ('outliers'; 15% of the study population), Diff BIA À D2O was high (À 6.8 to þ 3.8 l). Diff BIA À D2O was associated with individual variations in body shape rather than ECF composition. Using gender-specific analysis, we found that individual variability of waist circumference in men and arm length in women significantly contributed to Diff BIA À D2O. When removing the four 'outliers', these associations were lost. CONCLUSIONS: In the majority of our sample, BIA agreed well with D 2 O. Adjusting for individual variability in body shape by anthropometrical assessment could possibly improve the accuracy of SF-BIA for individuals who deviate from mean values with respect to body shape. However, further studies with higher subject numbers are needed to confirm our findings.
Analytic assessment of the various bioimpedance methods used to estimate body water
Journal of applied physiology (Bethesda, Md. : 1985), 1998
Knowledge of patient fluid distribution would be useful clinically. Both single-frequency (SF) and impedance modeling approaches are proposed. The high intercorrelation between body water compartments makes determining the best approach difficult. This study was conducted to evaluate the merits of an SF approach. Mathematical simulation was performed to determine the effect of tissue change on resistance and reactance. Dilution results were reanalyzed, and resistance and parallel reactance were used to predict the intracellular water for two groups. Results indicated that the amount of intracellular and extracellular water conduction at any SF can vary with tissue change, and reactance at any SF is affected by all tissue parameters. Modeling provided a good prediction of dilution intracellular and extracellular water, but an SF method did not. Intracellular, extracellular, and total body water were equally predicted at all frequencies by SF resistance and parallel reactance. Extrace...
International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity, 1997
To validate the assessment of total body water (TBW) and extracellular water (ECW) by multi-frequency bioelectrical impedance. Twenty-five overweight but otherwise healthy subjects and 20 lean subjects. Cross-sectional. TBW and ECW were determined by dilution techniques. Prediction equations from the literature were used to calculate TBW and ECW from measured impedance at 100 and 50 kHz or 1 and 5 kHz, respectively. In 18 of the obese subjects, impedance was also measured with the electrodes placed at proximal sites. In lean and obese subjects, significant correlations were observed between the impedance index (H2/Z) at high frequencies with TBW (r = 0.90, P < 0.001 in lean and r = 0.80, P < 0.001 in obese subjects) and at low frequencies with ECW (r = 0.87, P < 0.001 and r = 0.77, P < 0.001 respectively). Proximal placement of electrodes slightly improved the correlation between the impedance index and TBW (from r = 0.83 to r = 0.90 at 50 kHz and from r = 0.85 to r = 0....
Making the choice between bioelectrical impedance measures for body hydration status assessment
Scientific Reports
Situational or persistent body fluid deficit (i.e., de- or hypo-hydration) is considered a significant health risk factor. Bioimpedance analysis (BIA) has been suggested as an alternative to less reliable subjective and biochemical indicators of hydration status. The present study aimed to compare various BIA models in the prediction of direct measures of body compartments associated with hydration/osmolality. Fish (n = 20) was selected as a biological model for physicochemically measuring proximate body compartments associated with hydration such as water, dissolved proteins, and non-osseous minerals as the references or criterion points. Whole-body and segmental/local impedance measures were used to investigate a pool of BIA models, which were compared by Akaike Information Criterion in their ability to accurately predict the body components. Statistical models showed that ‘volumetric-based’ BIA measures obtained in parallel, such as distance2/Rp, could be the best approach in pre...
Int J Environ Res Public Health, 2020
The aims of this study were to analyze the usefulness of raw bioelectrical impedance (BI) parameters in assessing water compartments and fluid distribution in athletes. A total of 202 men and 71 female athletes were analyzed. Total body water (TBW) and extracellular water (ECW) were determined by dilution techniques, while intracellular water (ICW) was calculated. Fluid distribution was calculated as the ECW/ICW ratio (E:I). Phase angle (PhA), resistance (R) and reactance (Xc) were obtained through BI spectroscopy using frequency 50kHz. Fat (FM) and fat-free mass (FFM) were assessed by dual-energy X-ray absorptiometry. After adjusting for height, FM, FFM, age and sports category we observed that: PhA predicted ICW (females: β = 1.62, p < 0.01; males: β = 2.70, p < 0.01) and E:I (males and females: β = -0.08; p < 0.01); R explained TBW (females: β = -0.03; p < 0.01; males: β = -0.06; p < 0.01) and ECW (females: β = -0.02, p < 0.01; males: β = -0.03, p < 0.01) and...