Whole-body Bioelectrical Impedance Research Articles

Tele-Pulmonary Rehabilitation and Mediterranean-like Lifestyle, Adjunctively to Continuous Positive Airway Pressure in Obstructive Sleep Apnea Patients: Effects in Fitness and Oxidative Indicators

Obstructive sleep apnea (OSA), often overlooked by clinicians, may lead to negative outcomes if left untreated. In this study, we examined the efficacy and efficiency of a 12-week unsupervised tele-rehabilitation program in OSA patients and focused on the potential changes in their fitness indicators and oxidative status. Forty OSA patients were allocated into two groups: the CPAPgroup (AHI 52.0 ± 31.5 events/h; age, 49.7 ± 9.4 years; BMI, 32.1 ± 7.6 kg/m2; control group) versus the non-CPAPgroup (AHI 38.2 ± 21.5 events/h; age, 49.3 ± 10.7 years; BMI, 32.3 ± 5.1 kg/m2; intervention group; personalized recommendations for nutrition—based on the Mediterranean diet—and exercise programs). Measurements included anthropometric characteristics and body composition through whole-body bioelectrical impedance analysis. In addition, participants underwent blood sampling for reactive oxygen metabolites’ levels (d-ROM), plasma antioxidant capacity (PAT), and Lipoprotein (a) (Lp(a)), as well as a 6 min walk test (6MWT). Statistically significant differences were detected in both groups (CPAPgroup versus non-CPAPgroup) after 12 weeks between Lp(a) (−32.2 ± 25.5%, p = 0.021 versus −17.7 ± 16.3%, p = 0.034) and 6MWT (16.6 ± 9.3%, p < 0.001 versus 7.5 ± 6.6%, p = 0.002). ΔNRO2 (oxygen saturation difference between nadir during sleep and resting awake) was significantly associated with d-ROMs levels (p = 0.045), resting mean arterial pressure (p = 0.024), and chest circumference in maximal inhalation and exhalation (Δchest, p < 0.001). To conclude, lifestyle interventions with unsupervised tele-exercise-rehabilitation pulmonary programs and Mediterranean-like diet may serve as adjunctive-to-CPAP therapeutic elements.

Usefulness of the skeletal muscle index in postoperative ileus of colorectal cancer patients: a retrospective cohort study

BackgroundPostoperative complications of colorectal cancer mainly include infections (surgical site infection, remote infection, etc.), post-operative ileus (POI), and anastomosis leakage. POI reportedly prolongs the hospital stay and increases medical costs. Therefore, predicting POI is very important. There have been some reports on the relationships between sarcopenia and postoperative complications in colorectal cancer patients, but none have been limited to POI. We therefore conducted a retrospective clinical study with a logistic regression analysis to confirm the risk factors for ileus after colorectal cancer surgery.MethodsWe retrospectively analyzed 213 patients who underwent elective oncological colorectal surgery for colorectal cancer from November 2017 to July 2021. The skeletal muscle mass (SMM, kg) was estimated using a whole-body bioelectrical impedance analysis (BIA), and the skeletal muscle index (SMI) was calculated as the SMM/height2. We divided all patients into 2 groups based on a low SMI (male < 8.958 kg/m2, female < 8.443 kg/m2) or normal SMI. Preoperative and intraoperative factors as well as, postoperative outcomes were then compared between the two groups.ResultsThe median (range) age of the 213 included patients was 72.0 (33–91) years old. Complications were noted in 96 patients (45.1%), including 21 (9.9%) with POI. There were 68 (31.9%) low SMI patients. POI occurred significantly more frequently in low SMI patients (19.1%) than in normal SMI patients (5.5%) (p = 0.005). In the multivariate analysis, bleeding (p = 0.039) and a low SMI (p = 0.031) were significantly associated with POI. In addition, a propensity score matching analysis was performed to further reduce the selection bias. As a result, a low SMI was the only independent POI predictor among the 78 matched cases.ConclusionA preoperative low SMI in colorectal cancer patients was considered a risk factor for POI.

Association of Birth Weight, Body Composition and Blood Pressure During Infancy in 1-Year-Old Jamaican Children

ObjectivesTo investigate the association of birth weight (BW), body composition (BC), and blood pressure (BP) in healthy, one-year-old infants in Jamaica.MethodsA cross-sectional study where fat-free mass (FFM) and fat mass (FM) was assessed by whole-body bioelectrical impedance analysis (BIA) and skinfold thickness measurements in a sample of 101 healthy one-year-old infants (58 girls and 43 boys). Oscillometric Blood Pressure was measured in triplicate in each infant. The main independent variable was birth weight. Pearson's correlation test and multiple linear regression were used to analyze the association between birth weight and body composition and blood pressure..ResultsSignificant associations were observed between birth weight and fat-free mass(r = 0.35.p = 0.0001) and fat mass(r = 0.25.p = 0.013) at the simple bivariate level, weight, and length significantly correlated with body composition using the multiple linear regression. 12% of girls and 265 of boys had excess body fat. The mean BP was 110/67 mm Hg for boys and 108/67 mm Hg for girls. At the bivariate level, birth weight was significantly correlated with systolic blood pressure (r = 0.21, p = 0.019). There was no association between birth weight and blood pressure in the regression models. Socioeconomic status did not impact the association of birth weight and body composition in this study. Significant associations were observed between birth weight and fat-free mass(r = 0.35.p = 0.0001) and fat mass(r = 0.25.p = 0.013) at the simple bivariate level, weight, and length significantly correlated with body composition using the multiple linear regression. 12% of girls and 265 of boys had excess body fat. The mean BP was 110/67 mm Hg for boys and 108/67 mm Hg for girls. At the bivariate level, birth weight was significantly correlated with systolic blood pressure (r = 0.21, p = 0.019). There was no association between birth weight and blood pressure in the regression models. Socioeconomic status did not impact the association of birth weight and body composition in this study.ConclusionsIn this sample of one-year-old infants, birth weight was associated with fat-free mass and fat mass, and weight and length were associated with fat-free mass, fat mass, and percentage body fat.Funding SourcesThis research was not funded.

Association of serum fibroblast growth factor 21 levels with skeletal muscle mass and mortality in chronic hemodialysis patients

Fibroblast growth factor 21 (FGF21) is a hormone that modulates metabolic pathways, which acts as a myokine under metabolic stress. We aimed to explore the association of serum FGF21 levels with skeletal muscle mass and mortality in patients on hemodialysis (HD). Baseline serum FGF21 levels were measured, and a portable whole-body bioelectrical impedance device was used to assess skeletal muscle mass. One hundred twenty-four patients undergoing chronic HD were categorized into high- and low-FGF21 groups according to the median FGF21 value. Patients with low FGF21 values had lower body weight, body mass index, skeletal muscle mass index (SMI=skeletal muscle mass/height2), and serum triglyceride levels. Log serum FGF21 levels revealed a modest but positive correlation with SMI (r=0.30, p=0.001) and independently predicted SMI after multiple adjustment (β=1.59, p=0.027). During a median follow-up period of 66 months, all-cause mortality and cardiovascular death rates did not differ significantly between the high- and low-FGF21 groups. We also failed to demonstrate FGF21 as an independent predictor of all-cause mortality. Serum FGF21 levels exhibited a positive association with skeletal muscle mass but were not predictive of mortality in patients undergoing chronic HD.

Association of handgrip strength and endurance with body composition in head and neck cancer patients.

Introduction:Assessment of skeletal muscle function (SMF) is of clinical relevance in the prediction of treatment outcome and to decide on optimal management of head & neck cancer (HNC) patients. Handgrip strength (HGS) & handgrip endurance (HGE) are considered as surrogate marker for whole-body skeletal muscle function. Further, SMF depends substantially on the body composition (BC). Hence in this study, we compared BC, HGS and HGE between HNC patients and healthy controls and also analysed the association of HGS, HGE with body composition in HNC patients.Methods:A cross-sectional study, conducted in 44 subjects in the age between 18 to 60 years. Twenty-two were histologically proven HNC patients prior to cancer-specific treatment and twenty-two age and gender-matched healthy volunteers. The parameters recorded were Height, weight, waist circumference, hip circumference, HGS, HGE and BC. Hand-held dynamometer was used to measure HGS and HGE measured using a stopwatch. BC was estimated by whole-body bioelectrical Impedance analysis method using Bodystat Quad scan 4000 device.Result:Comparison of data between HNC patient & healthy control was done by Student's t test. HGS, HGE, lean body mass (LBM), fat-free mass index (FFMI), Phase angle (PA), body cell mass (BCM) and body cell mass index (BCMI) were found to be reduced significantly in HNC patients when compared to healthy subjects. Further, Pearson correlation analysis revealed a significant positive correlation of HGS & HGE with LBM, FFMI, PA, BCM & BCMI, whereas body fat mass index showed a negative correlation with HGS & HGE in HNC patients.Conclusion:Our findings revealed, a significant reduction in HGS, HGE in patient with HNC which denotes decreased skeletal muscle function and it is linearly associated with low muscle mass, body cell mass and phase angle.

Development and validation of BIA prediction equations of upper and lower limb lean soft tissue in athletes.

Knowing the distribution of lean soft tissue (LST) among the body segments is of relevance for optimizing athletic performance, monitoring response to training, and for evaluating injury risk. Bioelectrical impedance (BIA) is a portable, low cost, and easy technique to assess body composition. However, most equations used by BIA to predict LST are not specific for the athlete population. The aim of this investigation was to develop and validate equations to estimate dual-energy X-ray absorptiometry (DXA) appendicular LST of the arms and legs based on whole-body BIA in athletes. Arms and legs LST were assessed by DXA and whole-body reactance (Xc) and resistance (R) were measured by BIA in athletes from various sports. Using measures of height, the resistance index (RI) (RI = height2/R) was calculated. Prediction equations were established using a cross-validation method where 177 athletes (2/3 of sample) were used for equation development and the remaining 88 athletes (1/3 of sample) were used for equation validation. The developed prediction equations were as follows: arm LST = 0.940 × sex (0 = male; 1 = female) + 0.042 × total body weight (kg) + 0.080 × RI + 0.024 × Xc - 3.927; leg LST = 1.983 × sex (0 = male; 1 = female) + 0.154 × total body weight (kg) + 0.127 × RI - 1.147. Both equations validated well for the arms (mean difference = 0.11 kg, R2 = 0.89, pure error (PE) = 0.61) and for the legs (mean difference = 0.05 kg, R2 = 0.81, PE = 1.93 kg). There were no differences (p > 0.05) in the mean observed and predicted LST for the arms and legs. The developed BIA-based prediction equations provide a valid estimation of upper and lower body LST in athletes.

Development of a Segmental Bioelectrical Impedance Spectroscopy Device for Body Composition Measurement.

Whole-body bioelectrical impedance analysis for measuring body composition has been well-explored but may not be sensitive enough to changes in the trunk compared to changes in the limbs. Measuring individual body segments can address this issue. A segmental bioelectrical impedance spectroscopy device (SBISD) was designed for body composition measurement and a prototype was implemented. Compensation was performed to adjust the measured values to correct for a phase difference at high frequencies and to counteract the hook effect when measuring the human body. The SBISD was used to measure five subjects and was compared against three existing analyzers. For most segmental measurements, the SBISD was within 10% of the R0 and R∞ values determined with a Bodystat Multiscan 5000 and an Impedimed SFB7. The impedance values from the third reference device, a Seca 514, differed significantly due to its eight-electrode measuring technique, meaning impedance measurements could not be compared directly.

Effect of Moderate Intensity Physical Activity and Modality on Measures of Body Composition in Males

Exercise prior to body composition measures using air displacement plethysmography (ADP) and bioelectrical impedance (BIA) is generally contraindicated. Blood flow redistribution varies when using modalities such as treadmill walking (TW), leg cycling (LC) and arm cycling (AC) that may contribute to inaccuracies. Understanding the effect of physical activity using modalities on the accuracy of these devices have practical benefits. PURPOSE: To determine the effect of moderate intensity physical activity using different exercise modalities on body fat percent (BF%) measured by ADP, whole body bioelectrical impedance (WBIA), upper body bioelectrical impedance (UBIA), and lower body bioelectrical impedance (LBIA). METHODS: Seventeen male participants (33.1 ± 9.3 y; 23.0%-49.0% body fat) were included in the study. Participants exercised using TW, LC, and AC (45%-55% heart rate reserve) for 30 minutes on different days including a control condition. BF% was measured pre exercise (PreE), immediately post-exercise (PE0), 15 minutes post-exercise (PE15), 30 minutes post-exercise (PE30), 45 minutes post-exercise (PE45), and 60 minutes post-exercise (60PE) using ADP, WBIA, UBIA and LBIA at each time point. RESULTS: No differences were found during the control for PreE BF% for ADP (18.2 ± 9.9%), WBIA (17.8 ± 7.6%), UBIA (17.8 ± 6.5%), and LBIA (15.6 ± 8.0%). There was no effect of time during the control on BF% except when using UBIA (p=0.03). Using ADP, BF% at PE0 was significantly less than all other time points following TW and LC (p<0.05). Following AC, PE0 was significantly different from PE15-PE60, but not PreE (p=0.06). Using LBIA, after TW only BF% measured at PE15 and PE45 was significantly less than PreE (p<0.05). CONCLUSION: BF% measured by ADP after exercise decreases with all modalities, but generally returns to PreE measures within PE15. WBIA and UBIA BF% are not affected by exercise modality over time. However, LBIA BF% tends to decrease following TM but returns to PreE measures within 60 minutes.

Body composition evaluated by body mass index and bioelectrical impedance vector analysis in women with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a complex inflammatory disease that modifies body composition. Although body mass index (BMI) is one of the clinical nutrition tools widely used to assess indirectly nutritional status, it is not able to identify these body alterations. Bioelectrical Vector Analysis (BIVA) is an alternative method to assess hydration and body cell mass of patients with wasting conditions. To investigate the differences in nutrition status according to BMI groups (normal, overweight and obesity) and BIVA classification (cachectic and non-cachectic) in women with RA. Women with confirmed diagnosis of RA were included from January 2015 to June 2016. Whole-body bioelectrical impedance was measured using a tetrapolar and mono-frequency equipment. Patients were classified according to BMI as: low body weight (n = 6, 2.7%), normal (n = 59, 26.3%), overweight (n = 88, 39.3%) and obese (n = 71, 31.7%), and each group was divided into BIVA groups (cachectic 51.8% and non-cachectic 48.2%). A total of 224 RA patients were included, with mean age 52.7 years and median disease duration of 12 years. Significant differences were found in weight, arm circumference, waist, hip, resistance/height, reactance/height and erythrocyte sedimentation rate among all BMI groups. However, serum albumin levels were significantly different between cachectic and non-cachectic patients independently of BMI. In all BMI categories, cachectic groups had lower reactance and phase angle than non-cachectic subjects. RA patients with normal or even high BMI have a significantly lower muscle component. Evaluation of body composition with BIVA in RA patients could be an option for cachexia detection.

Arresting frailty and sarcopenia in cirrhosis: Future prospects.

Arresting frailty and sarcopenia in cirrhosis: Future prospects.

Evaluation of serum myostatin and sclerostin levels in chronic spinal cord injured patients.

Case-control study. To assess serum myostatin levels, bone mineral density (BMD), appendicular skeletal muscle mass (ASMM) and serum sclerostin levels in chronic spinal cord injured (SCI) patients and healthy controls. SCI centre in Italy. Blood samples, whole-body bioelectrical impedance analysis and BMD measurement with the ultrasound technique at the calcaneus level were taken from patients suffering from chronic SCI (both motor complete and incomplete) and healthy control subjects. A total of 28 SCI patients and 15 healthy controls were enrolled. Serum myostatin levels were statistically higher (P<0.01) in SCI patients compared with healthy controls. Similar results were found comparing both the motor complete and the motor incomplete SCI subgroups to healthy controls. Serum sclerostin was significantly higher in patients with SCI compared with healthy controls (P<0.01). BMD, stiffness and mean T-score values in SCI patients were significantly lower than those in healthy controls. Serum myostatin concentrations in the motor complete SCI subgroups correlated only with serum sclerostin levels (r(2)=0.42; P=0.001) and ASMM (r(2)=0.70; P=0.002) but not in healthy controls. Serum myostatin and serum sclerostin are significantly higher in chronic SCI patients compared with healthy controls. They are potential biomarkers of muscle and bone modifications after SCI. This is the first study reporting an increase in serum myostatin in patients suffering from chronic SCI and a correlation with ASMM.

The relationship between fat-free mass index and pulmonary hyperinflation in COPD patients.

Reduced fat-free mass (FFM), a common finding in chronic obstructive pulmonary disease (COPD), may indirectly impact peak exercise capacity through a greater level of pulmonary hyperinflation. We aimed to investigate if FFM index (FFM/squared height) impacts exercise induced dynamic hyperinflation in COPD patients. Fifty-four patients with moderate-to-very severe COPD performed a symptom limited incremental cardiopulmonary exercise tests with serial measurements of inspiratory capacity (IC). FFM was measured by whole-body bioelectrical impedance. Patients were 66.7 ± 7.7 years old with mean forced expiratory volume in 1 s (FEV₁) of 1.08 ± 0.41 L (42 ± 15% of predicted). Peak exercise IC was significantly (P < 0.05) correlated with IC at rest (r = 0.78), FEV₁(r = 0.66), FVC (r = 0.59), FFM (r = 0.38) and FFM index (r = 0.29). However, only FEV₁ and rest IC predict peak IC (r = 0.86; P < 0.01) in a multivariate linear regression analysis. FFM index was weakly associated with peak exercise IC in COPD patients. However, it ceased to be an independent predictor when corrected for expiratory airflow limitation (FEV₁) and lung hyperinflation at rest (rest IC).

Body composition by whole-body bioelectrical impedance and prediction of clinically relevant outcomes: overvalued or underused?

Body composition calculated using whole-body bioelectrical impedance analysis (BIA), almost invariably with height (H) and often with weight (W), can help patient management and predict clinical outcomes. This study aimed to examine the merits of this approach compared with simple anthropometry (W+H). Use was made of original data and validation studies based on reference body composition methods: water dilution, densitometry, dual-energy X-ray absorptiometry, and more robust methods. Prediction of clinical outcomes, including mortality and length of hospital stay, was examined in six studies of chronic obstructive pulmonary disease and a study with multiple patient groups. Vector analysis, phase angle, multi-frequency BIA and segmental impedance were not considered. In a broad range of study populations, from neonates to older people, in health and disease, body composition calculated using BIA with simple anthropometry frequently offered no advantage over W+H alone, but in some situations it was superior and in others inferior. In predicting clinically relevant outcomes, the fat-free mass index (FFMI), established using BIA, had comparable and sometimes greater power than body mass index (BMI), but none of the reviewed papers used FFMI calculated from W+H or BMI to predict clinical outcomes. A variable and generally weak evidence base was found to suggest that BIA with anthropometry is better at predicting body composition than simple anthropometry alone. No evidence was found from the reviewed studies that FFMI calculated from BIA and anthropometry was better at predicting clinical outcomes than FFMI calculated by simple anthropometry alone.

Is Lower-Body Bioelectrical Impedance Comparable to Whole-Body Bioelectrical Impedance in High School Students?

Literature has shown that the use of BMI is not the most accurate assessment of overweight status since it does not account for the composition of an individual's body potentially misclassifying individuals (Heyward, 2006). As an alternative to BMI, bioelectrical impedance analysis (BIA) assesses an individual's body composition through a flow of current or impedance that measures total body water and fat free mass (Heyward & Wagner, 2004). Gold standard scales, such as a tetrapolar analyzer (WBA), analyze the whole body via four electrodes that make contact with the hands and feet. Scales are available to assess body composition by upper-body impedance (UBIA) via hand-to-hand analyzers or lower-body impedance (LBIA) via foot-to-foot analyzers. WBA can be very costly and therefore LBIA or UBIA may be more economical especially for high school fitness assessments when a BMI alternative is desired. PURPOSE: To determine if there are any significant differences in the results obtained between LBIA, UBIA, and WBA scales under identical conditions. METHODS: Participants consisted of 164 high school students (F=77, M=87) with a mean age of 15.43±1.2 yrs. Measurements were taken for each participant using all three devices and repeated at two subsequent screenings. Each device calculated the total body water (TBW), lean body mass (LBM) and fat mass (FM). Weight was measured using the LBIA and WBIA scales and manually inputted into the UPIA. Height was measured using a portable stadiometer or height rod. Statistical findings were determined using one-way ANOVA and Tukey post-hoc. Significant differences for males and females were based off the Tukey post-hoc. RESULTS: When assessing all parameters, there were significant differences in TBW and FM between the UBIA and the WBIA. Gender comparison showed significant differences (p<.05) among females in LBM and FM between LBIA and WBIA as well as between the UBIA and LBIA. There were no significant differences in LBM and FM between the LBIA and WBIA. Among the males there was a significant difference in TBW between UBIA and WBIA as well as between LBIA and UBIA. However no statistical differences were seen in TBW between LBIA and WBIA. CONCLUSIONS: Lower-body bioelectrical impedance scales are a cost effective and reliable method for determining body composition in high school students.

Changes in Estimating Echocardiography Pulmonary Capillary Wedge Pressure After Hypersaline Plus Furosemide Versus Furosemide Alone in Decompensated Heart Failure

Background The aim of the study was to verify the effects of hypertonic saline solution (HSS) plus a high furosemide dose and light restriction of sodium intake compared with a high-dose infusion of furosemide alone on pulmonary capillary wedge pressure (PCWP), as determined by Doppler echocardiography and tissue Doppler imaging in patients suffering from decompensated heart failure. Methods and Results Consecutive patients in New York Heart Association functional class IV, unresponsive to oral high doses of furosemide up to 250–500 mg/d and/or combinations of diuretics, with ejection fraction <40%, serum creatinine <2 mg/dL, blood urea nitrogen ≤60 mg/dL, reduced urinary volume (<500 mL/24 h), and low natriuresis (<60 mEq/24 h) were randomized into 2 groups (double blind). The first group received a furosemide infusion (250 mg) plus HSS (150 mL 3.0% Na) bid and light Na restriction (120 mmol), and the second group received furosemide infusion (250 mg) twice daily, and low Na diet (80 mmol). The fluid intake of both groups was restricted (1 L/d). Body weight, whole-body bioelectrical impedance analysis (BIA), 24-hour urinary volume, and serum and urinary laboratory parameters were measured daily. Estimations of echocardiographic PCWP (Echo-PCWP) were detected on entry, 1 hour after concluding the initial treatment, and 6 days thereafter. A total of 133 patients (47 women and 86 men), aged 65–82 years, met the entry criteria.The HSS group revealed a significant increase in daily diuresis, natriuresis, and serum sodium compared with the furosemide group. Six days after treatment, renal function was significantly improved in the HSS group. Both groups showed a significant reduction in Echo-PCWP, but the HHS group revealed a faster reduction and significant lower values at 6 days compared with the group taking furosemide alone. We observed a positive correlation between values of Echo-PCWP and BNP and an inverse correlation between BIA parameters and Echo-PCWP. Conclusions Our data show that the combination of high diuretic dose and HSS infusion plus light restriction in dietary sodium intake determine a more rapid and significant hemodynamic stabilization through the improvement of echo-PCWP, BNP levels, and BIA parameters than the group treated without HSS.

A Two-Year Weight Reduction Program in Obese Sleep Apnea Patients

To evaluate the effects of a 2-year weight reduction program on respiratory disturbances, arousal index, daytime sleepiness, metabolic status, and quality of life in obese patients with obstructive sleep apnea syndrome (OSAS). Prospective intervention study of 33 consecutive obese OSAS patients (24 men, 9 women); 19 subjects used continuous positive airway pressure and 4 used mandibular retaining device, except during nights with sleep recording. The program consisted of 8 weeks of low calorie diet followed by group meetings with behavioral change support. Seventy percent of the patients completed the program; 67% completed the sleep recordings. The success rate for the apnea-hypopnea index (AHI) (< 20 and reduction > or = 50%) was 15% in the intention to treat (ITT) analysis. The AHI showed a nonsignificant decrease in mean values, from 43 to 28. The oxygen desaturation index (ODI) decreased from 42 to 23 (p = 0.010), arousal index from 24 to 11 (p = 0.019), body mass index from 40 to 35 (p = 0.003) and the Epworth Sleepiness Scale (ESS) from 9 to 5 (p = 0.026), all ITT. Metabolic status, physical functioning, and vitality evaluations improved only in the per protocol analysis. Reduction in weight correlated significantly to reductions in ESS (p = 0.038) and insulin levels (p = 0.002), respectively. There were no differences based on gender or use/non-use of OSAS treatment device. Our weight reduction program showed a limited success in reducing AHI. However, there were significant improvements in weight, ODI, arousal index, and subjective symptoms. We recommend the program as an adjunct treatment for well-motivated obese OSAS patients.

Validation of BIA in Obese Children and Adolescents and Re‐evaluation in a Longitudinal Study

Decrease in fat mass (FM) is a one of the aims of pediatric obesity treatment; however, measurement techniques suitable for routine clinical assessment are lacking. The objective of this study was to validate whole-body bioelectrical impedance analysis (BIA; TANITA BC-418MA) against the three-component (3C) model of body composition in obese children and adolescents, and to test the accuracy of our new equations in an independent sample studied longitudinally. A total of 77 white obese subjects (30 males) aged 5-22 years, BMI-standard deviation score (SDS) 1.6-3.9, had measurements of weight, height (HT), body volume, total body water (TBW), and impedance (Z). FM and fat-free mass (FFM) were calculated using the 3C model or predicted from TANITA. FFM was predicted from HT(2)/Z. This equation was then evaluated in 17 other obese children (5 males) aged 9-13 years. Compared to the 3C model, TANITA manufacturer's equations overestimated FFM by 2.7 kg (P < 0.001). We derived a new equation: FFM = -2.211 + 1.115 (HT(2)/Z), with r(2) of 0.96, standard error of the estimate 2.3 kg. Use of this equation in the independent sample showed no significant bias in FM or FFM (mean bias 0.5 +/- 2.4 kg; P = 0.4), and no significant bias in change in FM or FFM (mean bias 0.2 +/- 1.8 kg; P = 0.7), accounting for 58% (P < 0.001) and 55% (P = 0.001) of the change in FM and FFM, respectively. Our derived BIA equation, shown to be reliable for longitudinal assessment in white obese children, will aid routine clinical monitoring of body composition in this population.

Estimation of whole-body skeletal muscle mass by bioelectrical impedance analysis in the standing position

Summary Objective To develop a clinical method for evaluating skeletal muscle (SM) mass using whole-body bioelectrical impedance (BI) analysis in the standing position. Subjects Two hundred and forty-four volunteers (men=106 and women=138) participated in this study. The subjects were randomly separated into validation and cross-validation groups. Methods The whole-body impedance ( Z ) between the hands and feet was measured in the standing position. A stepwise multiple regression analysis was used to develop the prediction equation for SM mass. Whole-body SM mass, measured by magnetic resonance imaging (MRI), was used as a reference. Results BI index (height 2 / Z ), body surface area (BSA), gender, and age were selected as significant contributors to predict SM in the validation group. There was no significant difference between the measured and estimated SM mass and no systematic error in BI analysis in the cross-validation group. All data were pooled to generate the final regression equation: SM mass \( kg \) = \( 0.126 × BI index \) + \( 1.937 × BSA \) + \( − 0.062 × age \) + \( − 2.186 × gender \) − 2.881 , where age is in years. Gender for men=1 and women=2. Analysis revealed that the slope and intercept were not significantly different from one and zero, respectively. The r 2 and SEE values of the regression equation were 0.893 and 1.65kg, respectively. Conclusions Using our developed prediction equation, the BIA system can be used to accurately evaluate whole-body skeletal muscle mass with the subject in the standing position.

Influence of localized edema on whole-body and segmental bioelectrical impedance

ObjectiveTetrapolar whole-body (hand-foot) bioelectrical impedance (Z-body) is used in body composition analysis assuming homogeneous soft tissue hydration. Limbs and trunk contribute to Z-body by 90% and 10%, respectively. We determined the effect on Z-body of an edema localized in one leg. MethodsResistance (R) and reactance (Xc) components of Z vector were measured at 50 kHz (BIA-101, RJL Systems, Akern, Italy) in 20 adult male patients without edema, before and 3 d after a femoropopliteal bypass that induced pitting edema in the leg. Z-body was measured from hand to foot on the right and left sides. Z from the leg (Z-leg) was measured from the pair of electrodes on the foot and the other pair on the trochanter. Data were analyzed with the vector bioelectric impedance analysis (Vector BIA) method (Piccoli's RXc graph with 95% confidence ellipses). ResultsBefore surgery, the positions of the mean Z-body and Z-leg vectors from either side of the body were not significantly different (overlapping 95% confidence ellipses). After surgery, the mean Z-leg and Z-body vectors from the side without edema did not change position in the RXc plane with respect to the presurgery position. In contrast, the mean Z-leg and Z-body vectors of the body side with edema significantly (P < 0.05) shortened according to the Vector BIA patterns of fluid accumulation. ConclusionZ-body in the side of the body without edema is not sensitive to the edema localized in the leg on the opposite side and therefore can be used in the assessment of body composition in patients with edema in one leg.

Bioelectrical impedance and strength measurements in patients with heart failure: comparison with functional class

Objective Patients with chronic heart failure (HF) develop important changes in body composition. Nevertheless, the usual methods of body composition assessment can be misleading in patients with HF because tissue hydration is altered. Bioelectrical impedance vector analysis (BIVA) works without making any assumption about constant soft tissue hydration. In this study, patients with HF and systolic dysfunction (HFS) and preserved systolic function (HFPSF) underwent a body composition evaluation by the BIVA method; the comparison was done between New York Heart Association (NYHA) functional classes I–II and III–IV. Methods We studied 243 patients with HF, 140 (101 in NYHA I–II and 39 in III–IV) with HFS and 103 (67 in NYHA I–II and 36 in II–IV) with HFPSF. Whole-body bioelectrical impedance was measured using BodyStat QuadScan 4000, which is tetrapolar and multiple-frequency equipment. Results In both HF categories, reactance and phase angle were significantly lower, the impedance ratio of 200 kHz to that at 5 kHz was higher, and had significantly shorter and downsloping impedance vector in the NYHA III–IV group compared with the NYHA I–II group by gender. Conclusion Bioelectrical impedance analysis allows an easier evaluation of body composition and this might be particularly useful to stratify the severity of HF.