Effects of procedure, upright equilibrium time, sex and BMI on the precision of body fluid measurements using bioelectrical impedance analysis

Improving multidisciplinary management of patients living with obesity: The evaluation of seated bioimpedance measures and relationship to functional performance following targeted intervention

Management of obesity requires a multidisciplinary approach including physical activity interventions, which have significant impacts on overall health outcomes. Greater levels of lean muscle mass are significantly associated with improved health and reduced risk of comorbidities and should be preserved where possible when undertaking rapid weight loss. This article reports on the physical and functional outcomes achieved during a 12-week intensive multidisciplinary intervention targeting obesity and evaluates correlations between body composition and functional outcomes. We additionally aimed to investigate the test-retest reliability and levels of agreement in body composition measurements using bioimpedance spectroscopy between seated and standing positions. Of the 35 participants included in analysis, significant differences were observed between baseline and post-intervention measures. These included weight loss of 12.6 kg, waist circumference reduction of 10.5 cm, fat mass reduction by 2.9%, muscle mass increase by 1.6%, 54.5 m improvement in the 6-minute walk test and 3.8 rep improvement in the 30-second sit-to-stand test. No significant correlations were observed between physical and functional outcome measures. Excellent test re-test reliability was observed in bioimpedance spectroscopy seated measurements (ICC >.9). Significant differences were observed between seated and standing bioimpedance spectroscopy measurements, however they are regarded as small differences in a clinical setting.

The Effect of Passive Dehydration on Phase Angle and Body Composition: A Bioelectrical Impedance Analysis

Bioelectrical impedance analysis (BIA) is a method used to estimate body composition, and it relies mainly on the body's water content. Insufficient body water can introduce bias to body composition scores.

PURPOSE

To determine the effect of body weight loss elicited by passive dehydration on body composition scores, including phase angle (PhA).

METHODS

Twenty-five euhydrated apparently healthy and physically active men's (age = 22.6 ± 3.3 yr.; body mass = 76.7 ± 15.9 kg; height = 172.0 ± 6.3 cm) body composition variables and PhA were measured before and after sitting quietly for 5 h in a controlled environment (26.6 ± 1.7 °C, 72 ± 4.9%RH).

RESULTS

It was found that five hours of passive dehydration caused a loss in body weight (Δ = 0.76 ± 0.34 kg, p < 0.05) and a decrease in body fat estimation (Δ = 0.90 ± 0.87 kg, p < 0.001). Additionally, an increase in ECW (Δ = 0.12 ± 0.30 L, p < 0.021) and PhA (Δ = 0.10 ± 0.15°, p < 0.005) was observed.

CONCLUSION

Body weight loss due to passive dehydration decreased BIA-derived fat mass, and increased extracellular water and PhA in physically active and apparently healthy men. Nonetheless, these changes had a negligible effect on the accuracy of the equipment, rendering them clinically insignificant.

Worth the Wait? Time Course of Supine Shifts in Body Water Compartments on Variables of Bioelectrical Impedance Analysis

Bioelectrical impedance analysis (BIA) reference values are based on supine assessments. Little is known regarding the effects of time course shifts in body water compartments after assuming a supine position. The aim of this study was to characterize these effects and provide recommendations regarding the optimal waiting time to perform BIA. Thirty-eight healthy adults underwent BIA via the RJL Quantum Legacy analyzer immediately upon lying down and every 5 minutes for 15 minutes. Differences in resistance (R), reactance (Xc), intracellular (ICW), extracellular (ECW), total body water (TBW), body fat percentage (%BF), and phase angle (PhA) were assessed. There were small but significant increases in R, Xc, and %BF (all p<0.001), as well as small but significant decreases in ICW, ECW, and TBW (all p<0.001) over 15 minutes. No difference was observed for PhA (p=0.065). Average values changed over 15 minutes by +7.14Ω, +1.36Ω, -0.2L, -0.2L, -0.4L, +0.05° and +0.1% for R, Xc, ICW, ECW, TBW, PhA and %BF, respectively. BIA measurements are affected by shifts in body water compartments after assuming a supine position, but these differences lack clinical significance in healthy adults. Technicians working with healthy adults can perform BIA within 15 minutes after participants assume a supine position.

Drawings or 3D models: Do illustration methods matter when assessing perceived body size and body dissatisfaction?

Research has reported that both men and women experience body dissatisfaction. Among other instruments, a widely used method to assess perceived body size and body dissatisfaction are figure rating scales. Although a variety of illustration methods (e.g., three-dimensional, or 3D, models and line-drawing models) have been used to create these figure rating scales, to date, they have not been directly compared to one another. Thus, in the first study, which includes 511 participants at a mean age of 46 years old (range: 20–70), the present research work aims to assess how the line-drawing and 3D model scales, representing different body illustration methods, relate to each other. Furthermore, the first study assesses the validity of the indication of body dissatisfaction measured using these figure rating scales by comparing them to body checking or scrutinizing behavior and body appreciation levels. The project’s second study examines the two figure rating scales using objectively measured anthropometric data. In total, 239 participants at a mean age of 54 years (range: 18–94) were included. The results show that figure rating scales can be considered tools that measure perceptual body image due to their positive correlations with body checking behavior (for women) and their negative correlations with body appreciation. The 3D model and line-drawing scales show good to excellent inter-scale reliability, and both scales agree equally well with body mass index (BMI) measurements. Thus, the 3D model and line-drawing scales both seem well suited for assessing perceived body size and perceptual body dissatisfaction, suggesting that neither illustration method is superior to the other.

The centenary of the Harris-Benedict equations: How to assess energy requirements best? Recommendations from the ESPEN expert group

BACKGROUND & AIMS

The year 2019 marked the centenary of the publication of the Harris and Benedict equations for estimation of energy expenditure. In October 2019 a Scientific Symposium was organized by the European Society for Clinical Nutrition and Metabolism (ESPEN) in Vienna, Austria, to celebrate this historical landmark, looking at what is currently known about the estimation and measurement of energy expenditure.

METHODS

Current evidence was discussed during the symposium, including the scientific basis and clinical knowledge, and is summarized here to assist with the estimation and measurement of energy requirements that later translate into energy prescription.

RESULTS

In most clinical settings, the majority of predictive equations have low to moderate performance, with the best generally reaching an accuracy of no more than 70%, and often lead to large errors in estimating the true needs of patients. Generally speaking, the addition of body composition measurements did not add to the accuracy of predictive equations. Indirect calorimetry is the most reliable method to measure energy expenditure and guide energy prescription, but carries inherent limitations, greatly restricting its use in real life clinical practice.

CONCLUSIONS

While the limitations of predictive equations are clear, their use is still the mainstay in clinical practice. It is imperative to recognize specific patient populations for whom a specific equation should be preferred. When available, the use of indirect calorimetry is advised in a variety of clinical settings, aiming to avoid under-as well as overfeeding.

The effect of short-term exercise prehabilitation on skeletal muscle protein synthesis and atrophy during bed rest in older men

BACKGROUND

Poor recovery from periods of disuse accelerates age-related muscle loss, predisposing individuals to the development of secondary adverse health outcomes. Exercise prior to disuse (prehabilitation) may prevent muscle deterioration during subsequent unloading. The present study aimed to investigate the effect of short-term resistance exercise training (RET) prehabilitation on muscle morphology and regulatory mechanisms during 5 days of bed rest in older men.

METHODS

Ten healthy older men aged 65-80 years underwent four bouts of high-volume unilateral leg RET over 7 days prior to 5 days of inpatient bed rest. Physical activity and step-count were monitored over the course of RET prehabilitation and bed rest, whilst dietary intake was recorded throughout. Prior to and following bed rest, quadriceps cross-sectional area (CSA), and hormone/lipid profiles were determined. Serial muscle biopsies and dual-stable isotope tracers were used to determine integrated myofibrillar protein synthesis (iMyoPS) over RET prehabilitation and bed rest phases, and acute postabsorptive and postprandial myofibrillar protein synthesis (aMyoPS) rates at the end of bed rest.

RESULTS

During bed rest, daily step-count and light and moderate physical activity time decreased, whilst sedentary time increased when compared with habitual levels (P < 0.001 for all). Dietary protein and fibre intake during bed rest were lower than habitual values (P < 0.01 for both). iMyoPS rates were significantly greater in the exercised leg (EX) compared with the non-exercised control leg (CTL) over prehabilitation (1.76 ± 0.37%/day vs. 1.36 ± 0.18%/day, respectively; P = 0.007). iMyoPS rates decreased similarly in EX and CTL during bed rest (CTL, 1.07 ± 0.22%/day; EX, 1.30 ± 0.38%/day; P = 0.037 and 0.002, respectively). Postprandial aMyoPS rates increased above postabsorptive values in EX only (P = 0.018), with no difference in delta postprandial aMyoPS stimulation between legs. Quadriceps CSA at 40%, 60%, and 80% of muscle length decreased significantly in EX and CTL over bed rest (0.69%, 3.5%, and 2.8%, respectively; P < 0.01 for all), with no differences between legs. No differences in fibre-type CSA were observed between legs or with bed rest. Plasma insulin and serum lipids did not change with bed rest.

CONCLUSIONS

Short-term resistance exercise prehabilitation augmented iMyoPS rates in older men but did not offset the relative decline in iMyoPS and muscle mass during bed rest.

Total body water by BIA in children and young adults with normal and excessive weight

Background

Estimation of total body water (TBW) is essential for clinical care.

Objective

Evaluation of changes in TBW by bioelectrical impedance analysis (BIA) in children and young adults with excessive weight.

Design

Data was collected in individuals aged 3–21 years with normal (n = 202) or excessive body weight (n = 133). The BIA results from individuals with normal weight were compared with two previously published studies in children by isotope dilution methods.

Results

Individuals with excessive weight had a higher mean TBW (27.87 L, SE 0.368) for height and age as compared to individuals with normal weight (23.95 L, SE 0.298), P<0.001. However, individuals with excessive weight had lower mean TBW (24.93 L, SE 0.37) for weight and body surface area (BSA) as compared to individuals with normal weight (26.94 L, SE 0.287), P<0.001. Comparison with two previously published studies showed no significant differences in mean TBW with one ((p = 1.00) but a significant difference with another study (p = 0.001).

Conclusions

Individuals with excessive weight had 16.5% higher mean TBW for height and age and 7.4% lower TBW for weight and BSA as compared to normal weight individuals. Our study validates the feasibility of data collection in pediatric outpatient setting by BIA.

Comparison between bioelectrical impedance spectroscopy measurements and water volume displacement of ankle oedema variations during the course of a day

OBJECTIVE

The purpose of this study was to find relationships between variations in bioelectrical impedance spectroscopy (BIS) measurements and those obtained by water displacement (WD) and calf (C) and ankle (A) perimetry on legs of patients with venous insufficiency and lower limb oedema, some with positive pitting test (PPT), others with negative pitting test (NPT).

APPROACH

Twenty-nine (29) female subjects were clinically examined prior to inclusion in the trial. Measurements were taken once in the morning and then 6 h later, using perimetry, WD, and then BIS; subjects were standing. Leg volume was assessed using two WD volumeters, one 'Tall' (TWD) and one 'Short' (SWD). BIS was performed using a SFB7 impedance meter device (Impedimed^®).

MAIN RESULTS

Forty-three (43) legs with oedema were included. The results showed that 61% of the TWD variations variance was explained by SWD variations; less than 30% of the TWD variations variance was explained using BIS or perimetry alone, and 45% at best when used in combination. R₀, related to extracellular water, was the key BIS parameter. For NPT subpopulation (32 legs), the composite parameter (C² - A²)/R₀ explained more than 60% of the TWD variations variance. For PPT subpopulation (11 legs), small or statistically non-significant variance explanations were found.

SIGNIFICANCE

Combination of anthropometric and BIS parameters gave a better forecast of WD results than using only one or other. A novel composite parameter, (C² - A²)/R₀, better predicted TWD changes than other parameters hitherto used in literature, with improved estimates for the NPT subpopulation. Study n°ANSM 2017-A01063-50.

Multiple measures derived from 3D photonic body scans improve predictions of fat and muscle mass in young Swiss men

INTRODUCTION

Digital tools like 3D laser-based photonic scanners, which can assess external anthropometric measurements for population based studies, and predict body composition, are gaining in importance. Here we focus on a) systematic deviation between manually determined and scanned standard measurements, b) differences regarding the strength of association between these standard measurements and body composition, and c) improving these predictions of body composition by considering additional scan measurements.

METHODS

We analysed 104 men aged 19-23. Bioelectrical Impedance Analysis was used to estimate whole body fat mass, visceral fat mass and skeletal muscle mass (SMM). For the 3D body scans, an Anthroscan VITUSbodyscan was used to automatically obtain 90 body shape measurements. Manual anthropometric measurements (height, weight, waist circumference) were also taken.

RESULTS

Scanned and manually measured height, waist circumference, waist-to-height-ratio, and BMI were strongly correlated (Spearman Rho>0.96), however we also found systematic differences. When these variables were used to predict body fat or muscle mass, explained variation and prediction standard errors were similar between scanned and manual measurements. The univariable predictions performed well for both visceral fat (r2 up to 0.92) and absolute fat mass (AFM, r2 up to 0.87) but not for SMM (r2 up to 0.54). Of the 90 body scanner measures used in the multivariable prediction models, belly circumference and middle hip circumference were the most important predictors of body fat content. Stepwise forward model selection using the AIC criterion showed that the best predictive power (r2 up to 0.99) was achieved with models including 49 scanner measurements.

CONCLUSION

The use of a 3D full body scanner produced results that strongly correlate to manually measured anthropometric measures. Predictions were improved substantially by including multiple measurements, which can only be obtained with a 3D body scanner, in the models.

Body Positional Effects on Bioimpedance Spectroscopy Measurements for Lymphedema Assessment of the Arm

Background: Bioimpedance spectroscopy (BIS) measurements have conventionally been performed using a device that uses gel-backed electrodes with the patient in a supine position. More recently, impedance devices that use stainless steel electrodes with the patient in a standing position have become available. The aim of this study was to assess and compare BIS measurements made in three different body positions using two different impedance devices (lead device and stand-on device) in women with and without arm lymphedema. Methods: A cross-sectional study design was used to recruit two cohorts of women, healthy controls (n = 47) and those who had been diagnosed with breast cancer (n = 53) and were either at risk of (n = 14) or with unilateral arm lymphedema (n = 39). BIS measurements were taken three times in each position for each device. Results: Impedance measurements were reliably made using either a lead or stand-on device with a coefficient of variation being 0.6% or lower. Absolute impedance measurements for the stand-on device were larger than the comparable lead device values due to the difference in electrode position, but were highly correlated (r = 0.92, p < 0.0001). Interarm impedance ratios and L-Dex scores were slightly (3.1% equivalence), but significantly different. Conclusion: The findings support impedance measurements being made reliably using either the lead or stand-on device, representing supine and upright measurement positions, respectively. Data between devices were, however, not directly interchangeable.

Single-slice CT measurements allow for accurate assessment of sarcopenia and body composition

OBJECTIVES

To evaluate the correlation between simple planimetric measurements in axial computed tomography (CT) slices and measurements of patient body composition and anthropometric data performed with bioelectrical impedance analysis (BIA) and metric clinical assessments.

METHODS

In this prospective cross-sectional study, we analyzed data of a cohort of 62 consecutive, untreated adult patients with advanced malignant melanoma who underwent concurrent BIA assessments at their radiologic baseline staging by CT between July 2016 and October 2017. To assess muscle and adipose tissue mass, we analyzed the areas of the paraspinal muscles as well as the cross-sectional total patient area in a single CT slice at the height of the third lumbar vertebra. These measurements were subsequently correlated with anthropometric (body weight) and body composition parameters derived from BIA (muscle mass, fat mass, fat-free mass, and visceral fat mass). Linear regression models were built to allow for estimation of each parameter based on CT measurements.

RESULTS

Linear regression models allowed for accurate prediction of patient body weight (adjusted R² = 0.886), absolute muscle mass (adjusted R² = 0.866), fat-free mass (adjusted R² = 0.855), and total as well as visceral fat mass (adjusted R² = 0.887 and 0.839, respectively).

CONCLUSIONS

Our data suggest that patient body composition can accurately and quantitatively be determined by using simple measurements in a single axial CT slice. This could be useful in various medical and scientific settings, where the knowledge of the patient's anthropometric parameters is not immediately or easily available.

KEY POINTS

• Easy to perform measurements on a single CT slice highly correlate with clinically valuable parameters of body composition. • Body composition data were acquired using bioelectrical impedance analysis to correlate CT measurements with a non-imaging-based method, which is frequently lacking in previous studies. • The obtained equations facilitate a quick, opportunistic assessment of relevant parameters of body composition.

Magnetic resonance imaging quantification of dehydration and rehydration in vocal fold tissue layers

Clinicians commonly recommend increased hydration to patients with voice disorders. However, effects on clinical voice outcome measures have been inconsistent. Hydration-induced change within different layers of vocal fold tissue is currently unknown. Magnetic Resonance Imaging (MRI) is a promising method of noninvasively measuring water content in vocal folds. We sought to image and quantify changes in water content within vocal fold mucosa and thyroarytenoid muscle after dehydration and rehydration. Excised porcine larynges were imaged using proton density (PD) weighted MRI (1) at baseline and (2) after immersion in one of five hypertonic, isotonic, or hypotonic solutions or in dry air. Larynges dehydrated in hypertonic solutions or dry air were rehydrated and imaged a third time. Scans revealed fluid-rich vocal fold mucosa that was distinct from muscle at baseline. Baseline normalized signal intensity in mucosa and muscle varied by left vs. right vocal fold (p < 0.01) and by anterior, middle, or posterior location (p < 0.0001). Intensity changes in the middle third of vocal fold mucosa differed by solution after immersion (p < 0.01). Hypertonic solutions dehydrated the middle third of mucosa by over 30% (p < 0.001). No difference from baseline was found in anterior or posterior mucosa or in muscle after immersion. No association was found between intensity change in mucosa and muscle after immersion. After rehydration, intensity did not differ by solution in any tissue, and was not different from baseline, but post-rehydration intensity was correlated with post-immersion intensity in both mucosa and muscle (p < 0.05), suggesting that degree of change in vocal fold water content induced by hypertonic solutions ex vivo persists after rehydration. These results indicate that PD-MRI can be used to visualize large mammalian vocal fold tissue layers and to quantify changes in water content within vocal fold mucosa and thyroarytenoid muscle independently.

Comparison of Bioelectrical Impedance Analysis, Slaughter Skinfold-Thickness Equations, and Dual-Energy X-ray Absorptiometry for Estimating Body Fat Percentage in Colombian Children and Adolescents with Excess of Adiposity

Dual-energy X-ray absorptiometry (DXA) has been considered a reference method for measuring body fat percentage (BF%) in children and adolescents with an excess of adiposity. However, given that the DXA technique is impractical for routine field use, there is a need to investigate other methods that can accurately determine BF%. We studied the accuracy of bioelectrical impedance analysis (BIA) technology, including foot-to-foot and hand-to-foot impedance, and Slaughter skinfold-thickness equations in the measurement of BF%, compared with DXA, in a population of Latin American children and adolescents with an excess of adiposity. A total of 127 children and adolescents (11–17 years of age; 70% girls) from the HEPAFIT (Exercise Training and Hepatic Metabolism in Overweight/Obese Adolescent) study were included in the present work. BF% was measured on the same day using two BIA analysers (Seca^® 206, Allers Hamburg, Germany and Model Tanita^® BC-418^®, TANITA Corporation, Sportlife Tokyo, Japan), skinfold measurements (Slaughter equation), and DXA (Hologic Horizon DXA System^®, Quirugil, Bogotá, Columbia). Agreement between measurements was analysed using t-tests, Bland–Altman plots, and Lin’s concordance correlation coefficient (ρc). There was a significant correlation between DXA and the other BF% measurement methods (r > 0.430). According to paired t-tests, in both sexes, BF% assessed by BIA analysers or Slaughter equations differ from BF% assessed by DXA (p < 0.001). The lower and upper limits of the differences compared with DXA were 6.3–22.9, 2.2–2.8, and −3.2–21.3 (95% CI) in boys and 2.3–14.8, 2.4–20.1, and 3.9–18.3 (95% CI) in girls for Seca^® mBCA, Tanita^® BC 420MA, and Slaughter equations, respectively. Concordance was poor between DXA and the other methods of measuring BF% (ρc < 0.5). BIA analysers and Slaughter equations underestimated BF% measurements compared to DXA, so they are not interchangeable methods for assessing BF% in Latin American children and adolescents with excess of adiposity.

Comparison of body composition assessment by DXA and BIA according to the body mass index: A retrospective study on 3655 measures

BACKGROUND AND AIMS

Body composition assessment is often used in clinical practice for nutritional evaluation and monitoring. The standard method, dual-energy X-ray absorptiometry (DXA), is hardly feasible in routine clinical practice contrary to Bioelectrical Impedance Analysis (BIA) method. We thus aimed to compare body composition assessment by DXA and BIA according to the body mass index (BMI) in a large cohort.

METHODS

Retrospectively, we analysed DXA and BIA measures in patients followed in a Nutrition Unit from 2010 to 2016. Body composition was assessed under standardized conditions in the morning, after a fasting period of 12 h, by DXA (Lunar Prodigy Advance) and BIA (Bodystat QuadScan 4000, Manufacturer's equation). Bland-Altman test was performed for each class of BMI (kg/m2) and fat mass and fat free mass values were compared using Kruskal-Wallis test. Pearson correlations were also performed and the concordance coefficient of Lin was calculated.

RESULTS

Whatever the BMI, BIA and DXA methods reported higher concordance for values of FM than FFM. Body composition values were very closed for patients with BMI between 16 and 18,5 (difference < 1kg). For BMI > 18,5 and BMI < 40, BIA overestimated fat free mass from 3,38 to 8,28 kg, and underestimated fat mass from 2,51 to 5,67 kg compared with DXA method. For BMI ≥ 40, differences vary with BMI. For BMI < 16, BIA underestimated fat free mass by 2,25 kg, and overestimated fat mass by 2,57 kg. However, limits of agreement were very large either for FM and FFM values, irrespective of BMI.

CONCLUSION

The small bias, particularly in patients with BMI between 16 and 18, suggests that BIA and DXA methods are interchangeable at a population level. However, concordance between BIA and DXA methods at the individual level is lacking, irrespective of BMI.

Validity of Predictive Equations for Resting Energy Expenditure Developed for Obese Patients: Impact of Body Composition Method

Predictive equations have been specifically developed for obese patients to estimate resting energy expenditure (REE). Body composition (BC) assessment is needed for some of these equations. We assessed the impact of BC methods on the accuracy of specific predictive equations developed in obese patients. REE was measured (mREE) by indirect calorimetry and BC assessed by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). mREE, percentages of prediction accuracy (±10% of mREE) were compared. Predictive equations were studied in 2588 obese patients. Mean mREE was 1788 ± 6.3 kcal/24 h. Only the Müller (BIA) and Harris & Benedict (HB) equations provided REE with no difference from mREE. The Huang, Müller, Horie-Waitzberg, and HB formulas provided a higher accurate prediction (>60% of cases). The use of BIA provided better predictions of REE than DXA for the Huang and Müller equations. Inversely, the Horie-Waitzberg and Lazzer formulas provided a higher accuracy using DXA. Accuracy decreased when applied to patients with BMI ≥ 40, except for the Horie-Waitzberg and Lazzer (DXA) formulas. Müller equations based on BIA provided a marked improvement of REE prediction accuracy than equations not based on BC. The interest of BC to improve REE predictive equations accuracy in obese patients should be confirmed.