Tetrapolar Bioelectrical Impedance Analysis Research Articles

Resting Heart Rate Variability is Independently Associated with Visceral Fat Rating Scores in Saudi Adult Males.

Visceral adipose tissue (VAT) may be a specific modifiable contributor to body composition-related autonomic impairment. To compare heart rate variability (HRV) between groups stratified by visceral fat rating (VFR) and compare associations between HRV and body composition metrics. A cross-sectional study was conducted on healthy men (n=99,age=37.8±13.4 years, body mass index [BMI]=26.9±4.6 kg/m2). HRV was derived from 5-minute electrocardiographic recordings. Body composition (body fat percentage, VFR, and muscle mass to visceral fat ratio [MMVFR]) was estimated using tetrapolar bioelectrical impedance analysis. Participants were categorized into groups according to VFR: G1 (VFR=1-8); G2(VFR=9-12); and G3(VFR>12). Age-adjusted comparisons were made between groups. Independent associations were quantified with multiple linear regressions. P <0.05 was significant. Root-mean square of successive differences (RMSSD) and standard deviation of normal RR intervals (SDNN) were higher for G1 vs. G2 and G3 (p<0.05). Low-frequency power (LF) was higher in G1 than in G2 (p<0.05). VFR and MMVFR were negatively associated with SDNN, RMSSD, LF, and HF (p<0.05). After adjusting for age, BMI, and systolic and diastolic blood pressure, VFR was significantly predictive of RMSSD, SDNN, and HF (p=0.002,-0.027), and MMVFR was significantly predictive of RMSSD and SDNN (p=0.020,-0.023). Men in the lowest VFR category had the highest HRV. VFR was more strongly associated with HRV than body fat percentage and MMVR. Time domain parameters were more sensitive to VAT than frequency domain parameters. HRV parameters could be the primary parameters of interest in tracking cardiac-autonomic status in response to interventions targeting VAT reduction.

Bioelectrical impedance vector analysis evaluates cellularity and hydration in cirrhotic patients.

BACKGROUNDMalnutrition in cirrhotic patients is correlated with mortality and a better response to liver transplantation. However, recovery of the nutritional status in these patients is a challenge due to the difficulty in establishing a reliable nutritional diagnosis. The bioelectrical impedance vector analysis (BIVA) method appears as a feasible tool in clinical practice to define the physiological state of cirrhotic patients by assessing hydration and body cellularity.AIMTo evaluate body composition in cirrhotic patients using BIVA.METHODSThis retrospective cross-sectional study was carried out by following cirrhotic outpatients at a hospital in Porto Alegre, Brazil. A tetrapolar bioelectrical impedance analysis device was used to evaluate cellularity and hydration and to perform the BIVA. The BIVA graphic was elaborated by software and for statistical analysis a significance level of 5% (P ≤ 0.05) was considered.RESULTSOne hundred and ninety patients, 61.1% males, with a mean age of 56.6 ± 11.0 years, were evaluated. Of these, 56.3% had Child-Turcotte-Pugh (CTP) A score, and the prevalent etiology was hepatitis C virus (47.4%). The patients were classified according to cellularity and hydration by the quadrants and ellipses of the BIVA method, quadrant 1 (47.9%); quadrant 2 (18.9%); quadrant 3 (14.2%); and quadrant 4 (18.9%). Those classified in quadrant 1 and 2 had a higher phase angle compared to those in quadrants 3 and 4 (P < 0.001). Quadrant 2 patients had a lower average age than the other groups. The association with CTP score showed that patients in quadrant 2 had a higher proportion of CTP A, and those in quadrant 4 had a higher proportion of CTP C (P < 0.052).CONCLUSIONThe BIVA method allows identification of the cellularity and hydration status of cirrhotic patients, and its association with clinical factors determines the disease severity, age and prognostic index.

Association of phase angle and running performance

A high phase angle derived from bioelectrical impedance analysis has been linked to a high level of physical activity. However, it is unknown whether a high phase angle is related to running performance. We included all subjects who participated for the first time to the Course de l'Escalade between 1999 and 2016, a yearly city run occurring in Geneva. The subjects underwent a measurement by 50-kHz tetrapolar bioelectrical impedance analysis (Nutriguard®). Running time was converted to running speed in km/h. Results are shown as mean (SD) and as frequencies. We performed sex-specific univariate and multivariate regressions, adjusted for age, body mass index, categories of running distance and year of measurement, to evaluate whether the phase angle is associated with running speed. We analyzed 2264 subjects (1025 women and 1239 men). In univariate regressions, phase angle was significantly related to running speed in women (coeff 0.52, 95% CI 0.35-0.67, p<0.001, adjusted R2 0.037) and men (coeff 0.57, 95% CI 0.42-0.73, p<0.001, adjusted R2 0.039). Multivariate regressions showed that the phase angle was still significantly associated with running speed in women and men (p<0.001 for both models), with an adjusted R2 of 0.262 and 0.282, respectively. The phase angle is positively associated with running performance in men and women. It remains to be demonstrated if this association reflects the benefit of regular training and whether the phase angle might be suitable to monitor improvements in running performance. CLINICAL TRIAL REGISTRY: clinicaltrials.gov, identifier: NCT03400761.

Role of Bioelectrical Impedance Analysis in the Evaluation of Patients with Upper Limb Lymphedema.

Background: Monofrequency bioelectrical impedance analysis (BIA) protocols seek to further quantify changes in lymphedema compared with traditional circumferential evaluations. Complex decongestive therapy (CDT) is an effective method of reducing unilateral upper limb lymphedema secondary to breast cancer treatments. Comparing lymphedema measurements between segmental tetrapolar BIA, total body BIA, and circumferential measurements during therapeutic changes can improve our quantitative assessment ability for this prevalent medical complication. Methods and Results: Twenty-two patients with breast-cancer-related unilateral upper limb lymphedema participated in this prospective observational study. Circumferential measurements, segmental tetrapolar BIA, and total body BIA were obtained and compared before CDT, immediately after 10 sessions of CDT, and 30 days post-CDT to assess lymphedema. The segmental tetrapolar BIA correlated well with improvements in circumferential measurements of the limb. We found that the resistance value cutoff point of 237 Ω could indicate a recurrence of lymphedema. Conclusions: Segmental, tetrapolar monofrequency BIA provides a simple method to monitor and evaluate the efficacy of therapy in the outpatient setting by operators with minimal training. This protocol could aid quantitative evaluations of unilateral upper limb lymphedema.

Relative Accuracy of Bioelectrical Impedance Analysis for Assessing Body Composition in Children With Severe Obesity.

The accuracy of different bioelectrical impedance analysis (BIA) devices for assessing body composition in children with obesity is unclear. We determined the relative accuracy of 2 BIA devices compared to dual x-ray absorptiometry (DXA) in obese and severely obese children. We measured body composition in a cross-sectional study of 78 obese children by a handheld single frequency tetrapolar BIA device (Omron), a stationary multifrequency octopolar BIA device (InBody 370) and DXA. Intermethod agreement was assessed by intraclass correlations, paired t tests, and Bland-Altman analyses. Participants (37% female, age 14.8 ± 2.7 years) had mean (±standard deviation) body mass index of 36.7 ± 7.5 kg/m, body fat percentage of 46.4% ± 5.2%, and appendicular lean mass of 22.5 ± 6.0 kg by DXA. Intraclass correlations with DXA for body fat percentage were 0.39 and 0.87 for single frequency tetrapolar and multifrequency octopolar BIA devices, respectively. The single frequency tetrapolar BIA underestimated body fat percentage by 5.5% ± 2.9% (P < 0.0001). Differences between the multifrequency octopolar BIA and DXA for body fat percentage (-1.1% ± 2.8%) and appendicular lean mass (-0.3 ± 1.4 kg) were small, and 95% limits of agreement were approximately ±5%. BIA machines vary in relative accuracy in measuring body composition in children who are obese and severely obese. The multifrequency octopolar BIA device accurately estimated body fat percentage and appendicular lean mass relative to DXA and has the advantage of point of care performance.

Assessment of Changes in Body Composition During the First Postoperative Year After Bariatric Surgery

The potential effect of bariatric surgery on weight reduction and improvement of associated comorbidities is known, but the ratio obtained between the components of body weight, including lean body mass, body fat mass, and bone mass, is still not determined. This study aims to verify the changes in body composition during the first year after bariatric surgery. We conducted a prospective observational cohort study. Fifty patients who underwent bariatric surgery and maintained follow-ups were selected. Patients were assessed preoperatively and postoperatively for periods of 1, 3, 6, and 12months using tetrapolar bioelectrical impedance analysis and laboratory testing of lipids and serum albumin levels. Data were statistically analyzed. Statistically significant differences (p < 0.001) were obtained between the preoperative and 12-month evaluation respectively, for body mass index (BMI) (45.8 ± 7.5 to 30.0 ± 4.8kg/m2), FM (64.7 ± 15.5 to 30.6 ± 9.8kg), PFM (51.6 ± 4.17 to 37.3 ± 7.6%), and total cholesterol levels (197.1 ± 49.8 to 169.8 ± 31.0mg/dL). The decrease in PFM shows a better proportion between the body components. PFM showed significantly higher decrease in males than in females (p = 0.012). Lean body mass (p = 0.000) reduction was highest for patients operated by the Unified Health System (SUS, Government of Brazil) probably because of its few financial resources to maintain postoperative care. The change in body composition of patients who underwent Roux-en-Y gastric bypass was statistically significant for all variables examined during the first year postoperatively. This shows the effectiveness of the surgical procedure and clinical protocol set, which tends to favor a better health prognosis and weight maintenance in the long term.

Safety and Results of Bioelectrical Impedance Analysis in Patients with Cardiac Implantable Electronic Devices

Objective To analyze the dual interference between cardiac implantable electronic devices (CIEDs) and bioelectrical impedance analysis (BIA).Methods Forty-three individuals admitted for CIEDs implantation were submitted to a tetrapolar BIA with an alternating current at 800 microA and 50 kHz frequency before and after the devices’ implantation. During BIA assessment, continuous telemetry was maintained between the device programmer and the CIEDs in order to look for evidence of possible electric interference in the intracavitary signal of the device.Results BIA in patients with CIEDs was safe and not associated with any device malfunction or electrical interference in the intracardiac electrogram of any electrode. After the implantation of the devices, there were significant reductions in BIA measurements of resistance, reactance, and measurements adjusted for height resistance and reactance, reflecting an increase (+ 1 kg; P<0.05) in results of total body water and extracellular water in liter and, consequently, increases in fat-free mass (FFM) and extracellular mass in kg. Because of changes in the hydration status and FFM values, without changes in weight, fat mass was significantly lower (-1.2 kg; P<0.05).Conclusion BIA assessment in patients with CIEDs was safe and not associated with any device malfunction. The differences in BIA parameters might have occurred because of modifications on the patients’ body composition, associated to their hydration status, and not to the CIEDs.

813: Changes of body composition in women with BMI≥25 included in a lifestyle program. Correlation with birthweight’s centile

To evaluate if changes of body composition could affect the birthweight’s centile in overweight/obese women enrolled in an early lifestyle program. Two hundred and fourteen women with BMI≥25 were enrolled in an interventional study at 9th week, receiving a lifestyle program (hypocaloric, low-glycaemic index, low-saturated fat diet + specific physical activity recommendations). The tetrapolar bioelectrical impedance analysis (BIA) measured the gestational weight gain (GWG), the whole and regional fat mass (FM) and fat free mass (FFM), at enrolment and at 36th week. The primary outcome was the birthweigh’s centile. Age was 31.9±5.1 years (20-44). Most of women (78.6%) were Caucasian, pluriparous (61.9%) with a BMI of 43.6±5.9 (25.1-55.4). Obese of class I and II prevailed (62.4%) and 38 cases (17.7%) presented with BMI≥40. Those exceeding IOM recommendations (39.7%) had a significantly higher FM compared with those remaining into the ranges (5.5±3.6 vs 1.3±3.4 kg, p<0.001). Pre-pregnancy BMI didn’t show any correlation with birthweight’s centile. Both the GWG (p=0.01) and the changes in the FFM (p=0.002) (Figure), while not in the FM, at 36th week were correlated with the birthweight’s centile. The occurrence of GDM was 38.7% and these women had babies with significantly higher birthweight’s centile (p<0.001). After correcting for confounders (age, parity and pre-pregnancy BMI), the birthweight’s centile was independently associated with GDM (CR:14.9, p<0.0001), changes in FFM (CR:1.8, p=0.002) and, to a lesser extent, with GWG (CR:0.9, p=0.025). The rate of large for gestational age (LGA) and small for gestational age (SGA) babies are reported in the table. A reduction in FFM is associated with an increased risk of SGA babies (OR= 5.75, 95% CI: 1.59-20.87). GWG is a poor predictor of birthweight’s centile. Body composition changes, namely the decrease of the whole FFM, predict SGA babies in women submitted to a lifestyle program.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Accuracy of Commercial Body Composition Scales Versus Clinical Dual-Energy X-ray Absorptiometry and Bioelectrical Impedance Analysis

BACKGROUND: Body composition (BC) analysis is increasingly available to consumers in the form of wifi-connected bioelectrical impedance analysis (BIA) bathroom scales. However the accuracy of current generation scales to criterion methods is not known. PURPOSE: To determine the accuracy and precision of BC measurements using scales for men and women compared to dual-energy X-ray absorptiometry (DXA). In addition, we investigate the use of scales for quantifying resting metabolic rate (RMR). METHODS: We recruited a sample of convenience of healthy adults to undergo a series of BC measurements. Height and weight was assessed using a Seca 284. BC was accessed using whole-body DXA (Horizon A), a clinical tetrapolar multifrequency BIA (InBody770), and 7 bathroom scales: Tanita BF-684W, Weightwatchers WW701Y, Taylor 7226SFC, Withings Smart Body Analyzer WS-50 and Body Cardio WBS04, Fitbit Aria, and QardioBase. Duplicate measures were taken on the scales to evaluate the test-retest precision. RMR was calculated using Nelson RMR equations for DXA and BIA measures, and Harris-Benedict (HB) using weight. RESULTS: In total, 22 participants were recruited (12 male) with an average age of 29.6 (±7.3 years), weight of 70.0 (±13.4 kg) and height of 170.0 (±10.1 cm). PBF was highly correlated between the 770 and DXA for both men and women (r=0.9) but less correlated between the scales and DXA (0 < r < 0.65). However, all BIA devices underestimated PBF by 2 to 11 units. There was poor obesity classification between the scales and DXA as well (kappa < 0.2). RMR was highly correlated between DXA and scales for both men and women (r=0.50 to 0.99). RMR was overestimated by all scales compared to DXA from 21 to 184 kcal but in all cases were improvements over the HB RMR estimate (HB-DXA 260 kcal). The test-retest precisions (% coef of var, standard deviation) for PBF and RMR varied by model for men and women (0.2 to 0.5 %, NA) and (0.2 to 0.6 %, 2 to 9 kcal) respectively. Overall, we found the Tanita to have the best correlation to DXA measures, Taylor and Weight Watchers to have the best precision. CONCLUSIONS: We conclude that the use of bathroom scales may provide a more accurate assessment of RMR than the HB equation, and that the precision is comparable to previously-reported DXA values. However, our results varied substantially by make.

Whey Protein Supplementation Enhances Body Fat and Weight Loss in Women Long After Bariatric Surgery: a Randomized Controlled Trial.

The ideal nutritional approach for weight regain after bariatric surgery remains unclear. The objective of this study is to assess the effect of whey protein supplementation on weight loss and body composition of women who regained weight 24 or more months after bariatric surgery. This is a 16-week open-label, parallel-group, randomized controlled trial of women who regained at least 5% of their lowest postoperative weight after a Roux-en-Y gastric bypass (RYGB). A total of 34 participants were treated with hypocaloric diet and randomized (1:1) to receive or not supplementation with whey protein, 0.5g/kg of the ideal body weight. The primary outcomes were changes in body weight, fat free mass (FFM), and fat mass (FM), evaluated by tetrapolar bioelectrical impedance analysis (BIA). Secondary outcomes included resting energy expenditure, blood glucose, lipids, adiponectin, interleukin 6 (IL-6), and cholecystokinin levels. Statistical analyses included generalized estimating equations adjusted for age and physical activity. Fifteen patients in each group were evaluated: mean age was 45±11years, body mass index (BMI) was 35.7±5.2kg/m2, and time since surgery was 69±23months. Protein intake during follow-up increased by approximately 75% in the intervention group (p=0.01). The intervention group presented more body weight loss (1.86kg, p=0.017), accounted for FM loss (2.78, p=0.021) and no change in FFM, as compared to controls (gain of 0.42kg of body weight and 0.6kg of FM). No differences in secondary outcomes were observed between groups. Whey protein supplementation promoted body weight and FM loss in women with long-term weight regain following RYGB.

Resting Energy Expenditure and Body Composition of Women with Weight Regain 24Months After Bariatric Surgery.

Weight regain 24months after Roux-en-Y gastric bypass (RYGB) and low protein intake in patients without protein supplementation can favor fat-free mass loss and reduce resting energy expenditure (REE). We aimed to assess REE and its association with the body composition of women with weight regain and no protein supplementation in the late postoperative period of RYGB. We determined the body mass index (BMI), REE by indirect calorimetry, body composition by tetrapolar bioelectrical impedance analysis, and energy intake by two 24-h recalls of 34 patients with at least 5% of weight regain and no protein supplementation. The software SPSS v.17 analyzed the data calculating measures of central tendency and dispersion and using Pearson's correlation to test the association between the variables and the multivariate linear regression model at a p < 0.05 significance level. Postoperative period was positively associated with weight regain (r = 0.39; p = 0.023). The mean percentages of fat and fat-free masses were 45.1 ± 8.3% and 54.3 ± 8.1%, respectively. The mean REE was 1424.7 ± 187.2kcal (14kcal/kg of the current weight), mean energy intake was 1258.6 ± 454.3kcal, and mean protein intake was 0.9g/kg of the ideal weight ± 0.3. Fat-free mass was positively associated with REE regardless of protein intake and postoperative period. Female bariatric patients with weight regain and no protein supplementation lose fat-free mass, lowering their REE. Health practices that promote maintenance of BMI and body composition may lead to improved outcomes of bariatric surgery.

Different body fluid volumes measured by single- and multi-frequency bioelectrical impedance analyzers in overweight/obese renal patients.

Bioelectrical impedance analysis (BIA) is an affordable, non-invasive and fast alternative method to assess body composition. The purpose of this study was to compare two different tetrapolar BIA devices for estimating body fluid volumes and body cell mass (BCM) in a clinical setting among patients with kidney failure. All double measurements were performed by multi-frequency (MF) and single-frequency (SF) BIA analyzers: a Body Composition Monitor (Fresenius Medical Care, Germany) and BIA-101 (Akern, Italy), respectively. All procedures were conducted according to the manufacturers' instructions (dedicated electrodes, measurement sites, positions, etc). Total body water (TBW), extracellular water (ECW), intracellular water (ICW) and BCM were compared. The study included 39 chronic kidney disease patients (stage III-V) with a mean age of 45.8 ± 8 years (21 men and 18 women) who had a wide range of BMI [17-34 kg/m2 (mean 26.6 ±5)]. A comparison of results from patients with BMI <25 vs ≥25 revealed a significant discrepancy in measurements between the two BIA devices. Namely, in the group with BMI <25 (n=16) acceptable correlations were obtained in TBW (r 0.99; p<0.01), ICW (0.92; p<0.01), BCM (0.68; p<0.01), and ECW (0.96 p<0.05), but those with BMI ≥25 (n=23) showed a discrepancy (lower correlations) in TBW (r 0.82; p<0.05), ICW (0.78; p<0.05), BCM (0.52; p<0.05), and ECW (0.76; p<0.01). Since estimates of TBW, ICW and BCM by the present BIA devices do not differ in patients with BMI <25, they might be interchangeable. This does not hold true for overweight/obese renal patients.

Adipokines levels are associated with the severity of liver disease in patients with alcoholic cirrhosis.

To investigate the adipokine levels of leptin, adiponectin, resistin, visfatin, retinol-binding protein 4 (RBP4), apelin in alcoholic liver cirrhosis (ALC). Forty non-diabetic ALC patients [median age: 59 years, males: 35 (87.5%), Child-Pugh (CP) score: median 7 (5-12), CP A/B/C: 18/10/12, Model for End-stage Liver Disease (MELD): median 10 (6-25), follow-up: median 32.5 mo (10-43)] were prospectively included. The serum adipokine levels were estimated in duplicate by ELISA. Somatometric characteristics were assessed with tetrapolar bioelectrical impedance analysis. Pearson's rank correlation coefficient was used to assess possible associations with adipokine levels. Univariate and multivariate Cox regression analysis was used to determine independent predictors for overall survival. Body mass index: median 25.9 (range: 20.1-39.3), fat: 23.4% (7.6-42.1), fat mass: 17.8 (5.49-45.4), free fat mass: 56.1 (39.6-74.4), total body water (TBW): 40.6 (29.8-58.8). Leptin and visfatin levels were positively associated with fat mass (P < 0.001/P = 0.027, respectively) and RBP4 with TBW (P = 0.025). Median adiponectin levels were significantly higher in CPC compared to CPA (CPA: 7.99 ± 14.07, CPB: 7.66 ± 3.48, CPC: 25.73 ± 26.8, P = 0.04), whereas median RBP4 and apelin levels decreased across the spectrum of disease severity (P = 0.006/P = 0.034, respectively). Following adjustment for fat mass, visfatin and adiponectin levels were significantly increased from CPA to CPC (both P < 0.001), whereas an inverse correlation was observed for both RBP4 and apelin (both P < 0.001). In the multivariate Cox regression analysis, only MELD had an independent association with overall survival (HR = 1.53, 95%CI: 1.05-2.32; P = 0.029). Adipokines are associated with deteriorating liver function in a complex manner in patients with alcoholic liver cirrhosis.

Assessing appendicular skeletal muscle mass with bioelectrical impedance analysis in free-living Caucasian older adults

Aging is characterized by a loss of appendicular skeletal muscle mass (ASMM) leading to physical disability and death. Bioelectrical impedance analysis (BIA) is reliable in estimating ASMM but no prediction equations are available for elderly Caucasian subjects. The aim of the study was to develop and validate an equation derived from bioelectrical impedance analysis (BIA) to predict appendicular skeletal muscle mass (ASMM) in healthy Caucasian elderly subjects, taking dual X-ray absorptiometry (DXA) as the reference method, and comparing the reliability of the new equation with another BIA-based model developed by Kyle et al. (Kyle UG, Genton L, Hans D, Pichard C, 2003). With a cross-sectional design, 296 free-living, healthy Caucasian subjects (117 men, 179 women) over 60 years of age were enrolled. Lean mass of limbs was measured with DXA to ascertain ASMM (ASMMDxA). Whole-body tetrapolar BIA was performed to measure resistance (Rz), resistance normalized for stature (RI), and reactance (Xc). The BIA multiple regression equation for predicting ASMM was developed using a double cross-validation technique. The predicted ASMM values were compared with ASMMKyle, i.e. ASMM estimates derived from the model developed by Kyle et al. (Kyle et al., 2003). Cross-validation resulted in a unique equation using the whole sample: ASMM (kg) = -3.964 + (0.227*RI) + (0.095*weight) + (1.384*sex) + (0.064*Xc) [R(2) = 0.92 and SEE = 1.14 kg]. In our sample, ASMMKyle differed significantly from the ASMMDxA (p < 0.0001), with a mean error of -0.97 ± 1.34 kg (5.1 ± 6.9%). Unlike the present BIA prediction equation, the Kyle et al. model showed a correlation between the bias and the mean of ASMMDxA and ASMMKyle (r = -0.406, p < 0.001). The new BIA equation provides a valid estimate of ASMM in older Caucasian adults.

Predictive capacity of different bioelectrical impedance analysis devices, with and without protocol, in evaluation of adolescents

Objectivethis study was performed to determine the predictive capacity of four diffe- rent bioelectrical impedance analysis (BIA) devices in the assessment of adolescents, with and without a protocol. Methodsa cross-sectional study was performed with 215 adolescents aged 10 to 14 years, of both genders, evaluated through anthropometry and body composition by dual energy X-ray absorptiometry (DXA) and by four different BIA devices, with and without a protocol. The following tests were used: Kolmogorov-Smirnov's, chi-squared, Student's t or Mann-Whitney's, Kruskal-Wallis's, Wilcoxon's, and kappa index. The ROC curves were constructed and the sensitivity, specificity, and positive and negative predictive values were calculated. Resultsof the 215 adolescents, 44.2% had excessive body fat. The tetrapolar BIA device equipped with eight tactile electrodes showed more sensitivity and results that were closer to those obtained by DXA (area under the ROC curve [AUC] = 0.964 with protocol and AUC = 0.973 without protocol, p < 0.001), as well as greater agreement (k = 0.67 with protocol and k = 0.63 without protocol, p < 0.001). The evaluation without protocol was similar to that by DXA in most investigated situations (p > 0.05). ConclusionBIA is capable of predicting alterations in adolescents’ body composition. When it is impossible to perform the assessment with a protocol, its results may be useful in population studies.

Predictive capacity of different bioelectrical impedance analysis devices, with and without protocol, in the evaluation of adolescents

Objectivethis study was performed to determine the predictive capacity of four different bioelectrical impedance analysis (BIA) devices in the assessment of adolescents, with and without a protocol. Methodsa cross-sectional study was performed with 215 adolescents aged 10 to 14 years, of both genders, evaluated through anthropometry and body composition by dual energy X-ray absorptiometry (DXA) and by four different BIA devices, with and without a protocol. The following tests were used: Kolmogorov-Smirnov's, chi-squared, Student's t or Mann-Whitney's, Kruskal-Wallis's, Wilcoxon's, and kappa index. The ROC curves were constructed and the sensitivity, specificity, and positive and negative predictive values were calculated. Resultsof the 215 adolescents, 44.2% had excessive body fat. The tetrapolar BIA device equipped with eight tactile electrodes showed more sensitivity and results that were closer to those obtained by DXA (area under the ROC curve [AUC] = 0.964 with protocol and AUC = 0.973 without protocol, p < 0.001), as well as greater agreement (k = 0.67 with protocol and k = 0.63 without protocol, p < 0.001). The evaluation without protocol was similar to that by DXA in most investigated situations (p > 0.05). ConclusionBIA is capable of predicting alterations in adolescents’ body composition. When it is impossible to perform the assessment with a protocol, its results may be useful in population studies.

Accuracy of Consumer Grade Bioelectrical Impedance Analysis Devices Compared to Air Displacement Plethysmography

The purpose of this study was to examine the accuracy of percent body fat estimates from seven different bioelectrical impedance analysis (BIA) models and a seven-site skin fold formula (SKF) compared with air displacement plethysmography (ADP) in females. Eighty-two female volunteers ranging from 19-67 years (31.96 ± 1.39) enrolled in this study. Body composition was assessed by seven site skin folds (SKF), ADP, Tetrapolar BIA (TBIA), and five consumer grade BIA devices: finger to finger (FF), hand to hand (HH) and three different leg to leg (LL1, LL2, LL3) models. In addition, LL3 was analyzed using the athletic (LL3a) and non-athletic modes (LL3b). The Institutional Review Board for Human Subjects at Eastern Washington University approved this study. The participants represented a wide range of percentage body fat (BF) as assessed by ADP (8.40 to 47.10, mean = 26.15 ± 0.93 SEE). No difference in the estimated percent body fat was found between ADP and SKF, TBIA, FF, HH, LL1, LL2, LL3a, and LL3b (r=0.862, 0.553, 0.775, 0.771, 0.765, 0.791, 0.798, 0.796 respectively; P&lt;0.001). Bland-Altman plots of the differences between % fat by ADP and BIA versus average % fat by the two methods showed no systematic differences for SKF and the seven BIA models (mean differences ± SD : SKF, 1.92 ± 4.25; TBIA, 0.73 ± 7.3; FF, -1.55 ± 5.34, HH, 1.37 ± 5.35; LL1, -4.70 ± 5.40, LL2, -3.72 ± 5.12 and LL3a, 1.70 ± 5.07; LL3b, -6.11 ± 31.40 p&lt;0.05). Skin fold measures were found to be the most reliable field method of estimating body composition. Of the BIA machines tested, the strongest relationship was found in the LL models with the LL3 in athletic mode (LL3a) being the most reliable. For the more affordable models, the LL2 was the most reliable compared to ADP.

Relationship Between Basal Metabolic Rate, Gender, Age, and Body Composition in 8,780 White Obese Subjects

The objective of the present study was to explore the relationship between basal metabolic rate (BMR), gender, age, anthropometric characteristics, and body composition in severely obese white subjects. In total, 1,412 obese white children and adolescents (BMI > 97 degrees percentile for gender and age) and 7,368 obese adults (BMI > 30 kg/m(2)) from 7 to 74 years were enrolled in this study. BMR was measured using an indirect calorimeter equipped with a canopy and fat free mass (FFM) were obtained using tetrapolar bioelectrical impedance analysis (BIA). Using analysis of covariance, we tested the effect of gender on the relationship between BMR, age, anthropometry, and body composition. In children and adolescents, the predictor x gender interaction was significant in all cases except for FFM x gender. In adults, all predictor x gender interactions were significant. A prediction equation based on body weight (BW), age, and gender had virtually the same accuracy of the one based on FFM, age, and gender to predict BMR in both children and adults (R(2)(adj) = 0.59 and 0.60, respectively). In conclusion, gender was a significant determinant of BMR in children and adolescents but not in adults. Our results support the hypothesis that the age-related decline in BMR is due to a reduction in FFM. Finally, anthropometric predictors of BMR are as accurate as body composition estimated by BIA.

Avaliação de gordura corporal pela bioimpedância elétrica e sua correlação com diferentes pontos anatômicos de medida da circunferência da cintura em crianças

OBJECTIVE: To compare the different anatomical sites used in the measurement of waist circumference, as well as the effectiveness of these landmarks to predict the percentage of body fat by tetrapolar bioelectrical impedance analysis. METHODS: We evaluated 205 children from 6 to 9 years of age of both sexes. Data on weight, height and waist circumference were collected at three different sites: at the lower abdominal curvature, above the navel and at the midpoint between the last rib and the iliac crest. Nutritional status was assessed through the body mass index (BMI)/age as recommended by the World Health Organization. RESULTS: The sample was considered homogeneous in terms of sex, and the mean age was 7.2±1.2 years. Regarding nutritional status, 6.3% of the children had low weight, 75.1% were eutrophic, 7.3% were overweight, and 11.2% were obese. Among males, there was no statistical difference between the different sites of measurement; in females, the measurement above the navel was statistically higher. In the correlation analysis, the midpoint measurement showed the best correlation with percentage of body fat, with values of 0.50 in boys and 0.62 in girls. CONCLUSION: Waist circumference measured at the midpoint between the last rib and the iliac crest presented the best correlation with percentage of body fat.

Accuracy of Consumer Grade Bioelectrical Impedance Analysis Devices Compared to Air Displacement Plethysmography

PURPOSE: The aim of this study was to compare body composition measures between consumer grade models of bioelectrical impedance analysis (BIA), skin folds and a criterion methodology, air displacement plethysmography (ADP). METHODS: Eighty-two female volunteers ranging from 19–67 years (31.96 ± 1.39) enrolled in this study. Body composition was assessed by seven site skin folds (SKF), ADP, Tetrapolar BIA (TBIA), and five consumer grade BIA devices: finger to finger (FF), hand to hand (HH) and three different leg to leg (LL1, LL2, LL3) models. In addition, LL3 was analyzed using the athletic (LL3a) and non-athletic modes (LL3b). This study was approved by the Institutional Review Board for Human Subjects at Eastern Washington University. RESULTS: The participants represented a wide range of percentage body fat (BF) as assessed by ADP (8.40 to 47.10, mean = 26.15 ± 0.93 SEE). No difference in estimating percent body fat was found between ADP and SKF, TBIA, FF, HH, LL1, LL2 and LL3a (r=0.862, 0.553, 0.775, 0.771, 0.765, 0.791, 0.798, respectively; p<0.001). A significant difference in estimating percent body fat was found between ADP and LL3b (r=0.051, p<0.001, SEE = 8.42). Bland-Altman plots of the differences between % fat by ADP and BIA versus average % fat by the two methods showed no systematic differences for SKF and six BIA models (mean differences ± SD: SKF, 1.92 ± 4.25; TBIA, 0.73 ± 7.3; FF, −1.55 ± 5.34, HH, 1.37 ± 5.35; LL1, −4.70 ± 5.40, LL2, −3.72 ±5.12 andLL3a, 1.70 ± 5.07; p<0.05). Systematic differences were found for the LL3b BIA model (mean difference ± SD = −6.11 ±31.40). CONCLUSIONS: Skin fold measures were found to be the most reliable simple method of estimating body composition. Of the all BIA machines tested, the strongest relationship was found in the LL models with the LL3 in athletic mode being the most reliable. For the most affordable models, the LL2 model was the most reliable when comparing to ADP.