Bioelectrical Impedance Vector Analysis Research Articles

Hydration status according to impedance vectors and its association with clinical and biochemical outcomes and mortality in patients with chronic kidney disease.

Background: the evaluation of hydration status and body composition in patients with kidney disease is vital for proper management, since overhydration is associated with cardiovascular complications. Patients with chronic kidney disease (CKD) begin to show perceptible alterations in hydration during the intermediate stages of the disease; however, there is little information regarding the evaluation of blood volume status through bioelectrical impedance vector analysis (BIVA) in this population. Objective: to determine the association between hydration status measured with BIVA and biochemical and clinical parameters and mortality in patients with stage G3a, G3b and G4 CKD. Material and methods: A cross-sectional study was conducted with patients with stage G3a, G3b and G4 CKD who underwent bioelectrical impedance analysis (BIA). The following biochemical and clinical parameters were determined: serum and urinary albumin, hematocrit, serum electrolytes and creatinine, estimated glomerular filtration rate (eGFR, using the CKD-EPI formula), 24-hour urine output and blood pressure. The clinical and biochemical variables were associated with the components of the BIA. According to the resistance/height (R/H) and reactance/height (Xc/H) values, the BIVA results were individually plotted on reference ellipses to identify patients with abnormal hydration states. The patients were classified by group according to hydration status and CKD stage z-scores, and differences in clinical, biochemical and BIA parameters were identified. Mortality was determined by hydration status. Results: a total of 138 subjects, 69 men and 69 women, were studied. An association was found between the BIVA components (R/H, Xc/H and phase angle (PA) and serum albumin (albumin and R/H, r = -0.38, p = 0.001; Xc, r = 0.59, p = 0.000; PA, r = 0.58, p ≤ 0.0010). When the biochemical and clinical parameters were compared by hydration status, significant differences were found in eGFR (p = 0.01), serum calcium (p ≤ 0.001), serum albumin (p ≤ 0.001), hemoglobin (p = 0.04), hematocrit, (p = 0.04) and mean arterial pressure (p = 0.03). The patients were followed for a median of 65.5 months (IQR: 53.0 to 207.0), and 12 (8.6 %) patients with CKD died. The Kaplan-Meier curves showed that patients with overhydration had a significantly higher risk of death than patients with normal hydration. Conclusions: there is an association between the hydration status evaluated by BIVA and clinical and biochemical variables. Patients with overhydration are significantly more likely to die than patients with normal hydration.

Agreement between vector analysis and body composition measurements by four types of bioelectrical impedance technology in hemodialysis patients.

Background: the differences in bioelectrical impedance vector analysis (BIVA) results from different analyzers that use different bioelectrical impedance analysis (BIA) measurement technologies are not known. This study aimed to identify the degree of agreement between the BIVA results of four different BIA measurement techniques and to evaluate the degree of agreement between their estimates of fat-free mass (FFM) and fat mass (FM) and those determined by the gold-standard method of dual-energy X-ray absorptiometry (DEXA) in a subgroup of patients without overhydration. Methods: a cross-sectional study was conducted with hemodialysis (HD) patients with end-stage renal disease (ESRD) aged 18 to 65 years. BIA was measured with four different techniques: spectroscopic (BIA-BIS), multifrequency (BIA-MF), single-frequency (BIA-SF), and segmental multifrequency (BIA-MS) techniques. The differences and concordance between the components of the BIA (resistance, reactance, and phase angle) of the four devices were analyzed. Patients with a normal hydration status were identified, and concordance between FM and FFM measurements with each impedance device and DEXA was observed only in these patients. Results: thirty patients were included. The concordance between the components of BIA ranged from good to excellent (phase angle: intraclass correlation coefficient (ICC) = 0.82, 95 % confidence interval (CI): 0.77-0.93; resistance: ICC = 0.98, 95 % CI: 0.92-0.99). The overall concordance for BIVA diagnosis between the analyzers was substantial for hydration (k = 0.71, 95 % CI: 0.71-0.72) and for body tissues (k = 0.68, 95 % CI: 0.67-0.68). Bland-Altman plots showed the lowest bias between BIA-BIS and DEXA for both FM and FFM. Conclusions: the agreement among the four devices was good for diagnosis by BIVA. The BIA-BIS analyzer and DEXA had the lowest bias for both FFM and FM, although with higher limits of agreement. The lowest limits of agreement were found with the BIA-MS analyzer.

Bioelectrical Impedance Vector Analysis of Young Elite Team Handball Players.

Team handball is a highly dynamic sport where physical demands differ between categories and roles. Thus, physical characteristics are fundamental for the final performance. This study aims to (a) characterize a sample of young male and female elite team handball players with a non-athletic reference population; (b) to generate their 50%, 75%, and 95% percentiles of the bioelectrical variables. The study included 55 young elite team handball players (Males, n = 37, age = 17.0 ± 1.2 yrs, height = 185.8 ± 7.3 cm, weight = 82.0 ± 11.0 kg, body mass index (BMI) = 23.7 ± 2.5; Females, n = 18, age = 17.8 ± 0.9 yrs, height = 171.2 ± 6.4 cm, weight = 67.4 ± 7.2 kg, BMI = 23.0 ± 2.0). Height and bioelectrical variables were assessed in a state of euhydration and standard conditions. Bioelectrical impedance vector analysis (BIVA) was used to characterize the bioelectrical vector (BIA vector) distribution pattern for each group. Compared to the reference values, BIA vector showed statistically significant differences in males U17 (n = 19, T2 = 51.0, p < 0.0001), males U19 (n = 18, T2 = 82.0, p < 0.0001) and females U19 (n = 18, T2 = 85.8, p < 0.0001). Male groups were also bioelectrically different (T2 = 13.7, p = 0.0036). BIVA showed specific bioelectrical characteristics in young male and female elite handball players. This study provides an original data set of bioelectrical impedance reference values of young male and female elite team handball players. Our result might help to interpret individual bioimpedance vectors and define target regions for young handball players.

Association of electrical bioimpedance vectors with the nutritional classification of vulnerable multiethnic children.

Monitoring growth and body composition in childhood is vital for early detection of health and nutrition problems during child development. The bioelectrical impedance vector analysis (BIVA) revealed its effectiveness as an indicator of nutritional status. This study aimed to measure the bioimpedance vectors of a sample of multiethnic children and evaluate the utility of BIVA for the classification of the nutritional status in a group of children with greater vulnerability, including in the presence of obesity. This is a cross-sectional study that analyzed the bioelectrical impedance of a sample of 321 children from public daycare centers, aged 1-4 years, using the RXc graph method (tetrapolar analysis at 50kHz frequency). The 95%, 75%, and 50% tolerance ellipses were plotted by age group. The Z-scores of bioimpedance parameters (Xc/H-Z and R/H-Z) were calculated regarding age, which were used to build reference tolerance ellipses for a single group, regardless of age. Such ellipses were evaluated for their ability to recognize the pattern and classify the deviations, using individual vectors of obese children. The mean impedance vectors showed progressively higher reactances and lower resistances with age. In the group of obese children, the individual vectors located outside the 95% baseline tolerance ellipse were 12.5%, 18.75%, and 11.1% of the cases for the WHZ, WAZ, and BMIZ criteria, respectively, all above the expected 5%, but much below expectations. This may be a problem with the obesity criteria used, as WHZ, WAZ, and BMIZ do not differentiate fat from lean mass. Bioimpedance vector analysis reflects differences in the bioelectric patterns of children classified as obese. Provided the obesity criteria are constructed based on fat measurements, rather than lean mass, the use of tolerance ellipses in the BIVA chart is promising as a tool for monitoring nutritional status where measuring body composition is difficult, because constant tissue hydration cannot be assumed.

Prognostic Role of Malnutrition Diagnosed by Bioelectrical Impedance Vector Analysis in Older Adults Hospitalized with COVID-19 Pneumonia: A Prospective Study.

Background: Little is known on the clinical relevance of the nutritional status and body composition of patients hospitalized with SARS-CoV-2 infection. The aim of our study was to assess the prevalence of malnutrition in patients with COVID-19 pneumonia using bioelectrical impedance vector analysis (BIVA), and to evaluate the relationship of their nutritional status with the severity and outcome of disease. Methods: Among 150 consecutive patients who were hospitalized with COVID-19 pneumonia, 37 (24.3%) were classified as malnourished by BIVA, and were followed-up for 60 days from admission. Outcome measures were differences in the need for invasive mechanical ventilation, in-hospital mortality, and the duration of hospital stay in survivors. Results: During 60 days of follow-up, 10 (27%) malnourished patients and 13 (12%) non-malnourished patients required invasive mechanical ventilation (p = 0.023), and 13 (35%) malnourished patients and 9 (8%) non-malnourished patients died (p < 0.001). The average duration of the hospital stay in survivors was longer in patients with malnutrition (18.2 ± 15.7 vs. 13.2 ± 14.8 days, p < 0.001). In survival analyses, mechanical ventilation free (log-rank 7.887, p = 0.050) and overall (log-rank 17.886, p < 0.001) survival were significantly longer in non-malnourished than malnourished patients. The Cox proportional ratio showed that malnutrition was associated with an increased risk of mechanical ventilation (HR 4.375, p = 0.004) and death (HR 4.478, p = 0.004) after adjusting for major confounders such as age, sex, and BMI. Conclusions: Malnutrition diagnosed with BIVA was associated with worse outcomes in hospitalized patients with COVID-19 pneumonia.

Effects of the COVID-19 Lockdown on Body Composition and Bioelectrical Phase Angle in Serie A Soccer Players: A Comparison of Two Consecutive Seasons.

Simple SummaryIn 2020, the first Italian soccer league (Serie A) was canceled due to the COVID-19 pandemic. Consequently, a detraining process was triggered in soccer players, leading coaches and sports scientists to implement alternative training strategies to prevent a remodeling in body composition. This study tested the hypothesis that male elite soccer players, when confined to their home during the coronavirus disease 2019 pandemic, will display unfavorable trends in bioelectrical and body composition parameters. The results of the present study showed that reduction in phase angle and muscle mass occurred in soccer players during the coronavirus disease 2019 pandemic lockdown. Recognizing these adverse effects of a detraining period is critical in avoiding adverse effects on body composition in soccer players. In addition, the bioelectrical phase angle has been identified as a valid predictor of muscle mass changes during the competitive soccer season. Considerably, the phase angle represents a parameter that can be measured directly through bioelectrical impedance analysis, and it is independent of predictive equations such as those that quantify muscle mass. The present study compared changes in body composition during the COVID-19-associated lockdown with the same period of the following season in elite soccer players. Fifteen elite male soccer players (30.5 ± 3.6 years.) underwent a bioelectrical impedance analysis (BIA) before (end of February) and after (end of May) the lockdown, which occurred during the 2019/2020 season, and at the same period during the following competitive season in 2020/2021, when restrictions were lifted. Fat and muscle mass were estimated using predictive equations, while phase angle (PhA) and bioelectrical impedance vector analysis (BIVA) patterns were directly measured. After lockdown, fat mass remained unchanged (p > 0.05), while muscle mass (95%CI = −1.12/−0.64; ES = −2.04) and PhA (95%CI = 0.51/−0.24, ES = −1.56) decreased. A rightward displacement of the BIVA vector was also found (p < 0.001, ES = 1.50). After the same period during the regular season, FM% and muscle mass did not change (p > 0.05), while the PhA increased (95%CI = 0.01/0.22; ES = 0.63). A leftward vector displacement (p < 0.001, ES = 1.05) was also observed. The changes in muscle mass correlated with changes in PhA (“lockdown” season 2019/2020: ß = −1.128, p = 0.011; “regular” season 2020/21: ß = 1.963, p = 0.011). In conclusion, coaches and strength conditioners should monitor muscle mass in soccer players during detraining periods as this parameter appears to be mainly affected by changes in training plans.

Bioelectrical impedance vector analysis in patients on the waiting list for liver transplant: Associated factors and prognostic effects

ObjectivesThe aim of this study was to assess patients on the waiting list for liver transplant (LTx) according to bioelectrical impedance vector analysis (BIVA), as well as to verify the association between the placement of the vectors on the graph with clinical outcomes and identify the predictors to vector placement in quadrant 4 (Q4; indicating more hydration and less cellularity). MethodsThis was a retrospective observational study including 129 patients ≥20 y of age awaiting LTx. Patients’ nutritional status was assessed by using different tools, including single-frequency bioelectrical impedance analysis and the Subjective Global Assessment (SGA). Clinical data were registered. The BIVA was evaluated by comparing the individual vectors plotted for all patients to the tolerance ellipses of 50%, 75%, and 95% of the reference healthy population. The quadrant of the vector for each patient was registered. ResultsThe majority of the vectors were placed in Q1 (n = 54; 41.9%) and Q4 (n = 39; 30.2%). The presence of ascites or edema (hazard ratio [HR], 2.43; 95% confidence interval [CI], 1.15–5.12; P = 0.019) and the BIVA vector placed in Q4 in any ellipse (HR, 2.10; 95% CI, 1.07–4.09; P = 0.029) were independent predictors for mortality on the waiting list or ≤1 y after LTx. BIVA was not associated with longer hospital length of stay. The predictors of vector placement in Q4 were higher age, malnutrition according to SGA, and presence of ascites or edema. ConclusionPatients on the waiting list for LTx with BIVA vectors placed in Q4, in the 50%, 75%, or 95% tolerance ellipses, presented a worse prognosis.

Assessment of total and regional bone mineral density using bioelectrical impedance vector analysis in elderly population

This study aimed to investigate the relationship between bone mineral density (BMD) and height-adjusted resistance (R/H), reactance (Xc/H) and phase angle (PhA). A total of 61 male and 64 female subjects aged over 60 years were recruited from middle Taiwan. The R and Xc were measured using Bodystat Quadscan 4000 at a frequency of 50 kHz. BMD at the whole body, L2–L4 spine, and dual femur neck (DFN), denoted as BMDTotal, BMDL2–L4, and BMDDFN, were calculated using a Hologic DXA scanner. The R-Xc graph was used to assess vector shift among different levels of BMD. BMD was positively correlated with Xc/H and negatively correlated with R/H (p < 0.001). The General Linear Model (GLM) regression results were as follows: BMDTotal = 1.473–0.002 R/H + 0.007 Xc/H, r = 0.684; BMDL2–L4 = 1.526–0.002 R/H + 0.012 Xc/H, r = 0.655; BMDDFN = 1.304–0.002 R/H + Xc/H, r = 0.680; p < 0.0001. Distribution of vector in the R-Xc graph was significantly different for different levels of BMDTotal, BMDL2–L4 and BMDDFN. R/H and Xc/H were correlated with BMD in the elderly. The linear combination of R/H and Xc/H can effectively predict the BMD of the whole body, spine and proximal femur, indicating that BIVA may be used in clinical and home-use monitoring tool for screening BMD in the elderly in the future.

Applications of Bioelectrical Impedance Vector Analysis (BIVA) in the Study of Body Composition in Athletes

The study of body composition (BC) allows evaluating nutritional status, optimizing competitive performance, and monitoring the success of training regimens in athletes. Since BC reference techniques are expensive and/or invasive, in practice simpler, less expensive, and safer methods such as anthropometry are often used. The problem is that anthropometry requires a qualified anthropometrist, a rigorous measurement protocol using validated equipment, and a lengthy procedure because of its limited accuracy. Bioimpedance analysis (BIA) is an indirect method for estimating BC in a simple, fast, inexpensive, noninvasive, accurate, and reproducible manner. Despite the limitations of conventional BIA, it is still the most commonly used method for assessing BC in athletes. However, bioelectrical impedance vector analysis (BIVA) allows qualitative assessment of body cell mass (BCM) and hydration status without the need for biological assumptions and without being subject to conventional BIA errors. The purpose of this article was to demonstrate the uses and applications of BIA in the study of the BC and physical characteristics of athletes. For example, several practical cases of athletes from different sports were compared. The results obtained from somatotype studies, conventional BIA, and BIVA were included. BIVA interpretation and somatotype were consistent for all cases analyzed, but BIVA also provided information about hydration and BCM. The application of BIVA in the assessment of athletes can improve BC studies in sports because it is fast, simple, and reliable and neither imposes two-compartment-model limitations on BC estimation nor requires any biological assumptions.

Body composition analysis in patients with acute heart failure: the Scale Heart Failure trial.

AimsIn this study, we aimed to investigate whether body composition analysis (BCA) derived from bioelectrical impedance vector analysis (BIVA) could be used to monitor the hydration status of patients with acute heart failure (AHF) during intensified diuretic therapy.Methods and resultsThis observational, single‐centre study involved a novel, validated eight‐electrode segmental body composition analyser to perform BCA derived from BIVA with an alternating current of 100 μA at frequencies of 5, 7.5, 50, and 75 kHz. The BCA‐derived and BIVA‐derived parameters were estimated and compared with daily body weight measurements in hospitalized patients with AHF. A total of 867 BCA and BIVA assessments were conducted in 142 patients (56.3% men; age 76.8 ± 10.7 years). Daily changes in total body water (TBW) and extracellular water (ECW) were significantly associated with changes in body weight in 62.2% and 89.1% of all measurements, respectively (range, ±1 kg). Repeated measures correlation coefficients between weight loss and TBW loss resulted with rho 0.43, P < 0.01, confidence interval (CI) [0.36, 0.50] and rho 0.71, P > 0.01, CI [0.67, 0.75] for ECW loss. Between the first and last assessments, the mean weight loss was −2.5 kg, compared with the −2.6 L mean TBW loss and −1.7 L mean ECW loss. BIVA revealed an increase in mean Resistance R and mean Reactance Xc across all frequencies, with the subsequent reduction in body fluid (including corresponding body weight) between the first and last assessments.ConclusionsBody composition analysis derived from BIVA with a focus on ECW is a promising approach to detect changes in hydration status in patients undergoing intensified diuretic therapy. Defining personalized BIVA reference values using bioelectrical impedance devices is a promising approach to monitor hydration status.

The association between sarcopenia and functional outcomes after hospital discharge among critically ill surgical patients

To determine the association between sarcopenia in surgical intensive care unit (SICU) patients and long-term functional outcomes. This prospective, cohort study enrolled patients aged >65 years admitted to SICUs at the tertiary care hospital. Their muscle mass and strength were measured by bioelectrical impedance vector analysis (BIVA) and handgrip-strength or manual-muscle-strength tests. The functional outcomes were evaluated with the Thai version of the Barthel index for activities of daily living (ADL). 120 patients were enrolled. A multivariate analysis identified 3 independent predictors associated with poor functional outcomes (ADL scores ≤70) at one month after hospital discharge including sarcopenia (adjusted odds ratio [aOR]: 3.33; 95% confidence interval [CI]: 1.25-8.87); duration of mechanical ventilation (aOR: 1.19; 95% CI: 1.02-1.38); and length of hospital stay (aOR: 1.05; 95% CI: 1.01-1.10). Cox proportional-hazards regression models found that sarcopenia (adjusted hazard ratio [aHR]: 2.07; 95% CI: 1.02-4.22) and admission severity (aHR: 1.13; 95% CI: 1.04-1.23) were predictors of 120-day mortality. Sarcopenia was an independent predictor of poor functional outcomes at one month after hospital discharge.

Using bioelectrical impedance analysis in children and adolescents: Pressing issues.

Single- and multifrequency bioelectrical impedance analysis (BIA) has gained popularity as a tool to assess body composition and health status of children and adolescents, but many questions and misconceptions remain. This review addresses pressing issues researchers and health care providers may encounter when using BIA in the young population. The importance of choosing population-specific and device-specific equations to estimate body composition as well as the use of BIA in longitudinal analyses are discussed. When specific equations are not available, raw bioimpedance values (i.e., resistance, reactance, and impedance) can be used to compute bioimpedance parameters, such as phase angle, impedance ratio, and bioelectrical impedance vector analysis. As interpreting these parameters is challenging, suggestions are provided on the use of reference data, cut-off points, and adjustment factors. Furthermore, unsolved technical and analytical issues are listed. Based on existing issues and potential for future development, a greater interaction between industry and academic researchers to improve the validity of BIA measurements among children and adolescents across their developmental stages is encouraged.

Resistance but not elastic tubes training improves bioimpedance vector patterns and body composition in older women: A randomized trial

The present study aimed to investigate the effects of traditional resistance training compared to elastic tubes training on bioimpedance vector patterns, body composition, and strength in older women. Thirty-eight older women (age 68.7 ± 6.9 years, body mass index 28.8 ± 7.2 kg/m2) were randomly assigned to perform traditional resistance or elastic tubes training three times per week for 12 weeks. Body composition was assessed by dual energy X-ray absorptiometry and bioelectrical impedance vector analysis. In addition, handgrip strength was measured using a dynamometer. Only the participants who followed the 12-week traditional resistance training program significantly (p < 0.05) decreased fat mass (ES: −0.69) and extracellular water (ES: −1.06), and increased total body water (ES: 0.49), intracellular water (ES: 1.11), body cell mass (ES: 0.82), muscle mass (ES: 0.94), and phase angle (ES: 0.99), while no change occurred in the elastic tubes training group. Furthermore, a vector leftward displacement (ES: 1.11) into the resistance-reactance graph was found only after the traditional resistance training program. The handgrip strength increased for both traditional and elastic tubes training groups (ES: 0.64, ES: 0.71, respectively). Traditional resistance training improved body composition and strength in the older women group, while training using elastic tubes was effective only for the latter. The present outcomes encourage the use of systematic resistance training to counteract the effects of aging in older women.

Bioelectrical Impedance Vector Analysis (BIVA) for the monitoring of body composition in pregnancy.

During pregnancy, body composition alterations can be considered as markers of complications and in this context, a non-invasive and low-cost method such as Bioelectrical Impedance Vector Analysis (BIVA), can be employed to monitor such changes. This study aimed at identifying body compartments trend during physiological pregnancy. Classic and specific BIVA variables have been measured in a sample of 37 pregnant women approximately every 4 weeks of gestation and once postpartum. Researchers used both longitudinal and cross-sectional approach. The first case included data of women from the 11th to the 15th week along with data from the 28th to the 32nd week of gestation. The cross-sectional approach regarded two more specific moments (11th-12th weeks and 30th-31st weeks) and data within two months postpartum RESULTS: The longitudinal approach showed a significant decrease in classic BIVA variables (R/H, Xc/H, Z/H p < 0.001) and a shortening of the vector, pointing out that TBW and hydration increased significantly. Specific vector length increased significantly, indicating a physiological gain of FM% (p < 0.01). The cross-sectional approach showed lower values of R/H, Xc/H, Z/H between 12th-13th and 30th-31st weeks (p < 0.01), while in the postpartum period values tended to those registered at the beginning of pregnancy. No changes have been found for the phase angle in both approaches, indicating that ECW/ICW ratio remained constant CONCLUSIONS: Among physiological pregnancies, bioelectric values showed a coherent trend and these results represent a first contribution to support routine exams, leading to an early detection of anomalous values potentially correlated to pathologies.

Bioelectrical impedance vector applied to body composition evaluation of women survivors of breast cancer: A longitudinal study

Thus, the aim of this study was to assess the changes in the body composition of the women survivors of breast cancer and its association with clinical staging, using the bioelectrical impedance vector analysis (BIVA), over five years of follow-up. At baseline time 114 patients (T0) were selected and after 5 years (T1) of follow-up (n=35) data of weight, body mass index, waist circumference, phase angle, resistance/height, reactance/height, %fat free mass and %fat mass were monitored. Bioelectrical impedance vector analysis (BIVA) and the vector displacement assessment took place according to the initial and advanced clinical staging (CS 1 and 2, respectively) and time of follow-up and have been showed using mean graph and RXc score graph. Patients on CS 1 showed a reduction in reactance/height, phase angle, %fat free mass and an increase in %fat mass. The same group presented during the follow-up significant vector displacement by mean graph and a change to the 95% ellipse by the RXc score graph. Women with breast cancer in the initial CS showed a more significant displacement of bioelectric vectors, indicating worsening in body composition.

Specific Bioelectrical Impedance Vector Analysis Identifies Body Fat Reduction after a Lifestyle Intervention in Former Elite Athletes.

Simple SummaryThe ability of specific bioelectrical impedance vector analysis (BIVA) to classify subjects according to the percentage of fat mass has been recognized in different cross-sectional studies, but no longitudinal designs have yet been applied. The results of this investigations showed that specific BIVA can be used as a practical solution for assessing body composition management in former overweight/obese athletes. In particular, reductions in bioelectrical vector length adjusted according to the specific BIVA procedure were found to be associated with reductions in percentage of fat mass.Background: specific bioelectrical impedance vector analysis (BIVA) has been proposed as an alternative bioimpedance method for evaluating body composition. This investigation aimed to verify the ability of specific BIVA in identifying changes in fat mass after a 16-week lifestyle program in former athletes. Methods: The 94 participants included in the Champ4life project (clinicaltrials.gov: NCT03031951) were randomized into intervention (n = 49) and control (n = 45) groups, from which 82 athletes completed the intervention (age 43.9 ± 9.2 y; body mass index 31.1 ± 4.6 kg/m2). Fat mass was estimated by dual-energy X-ray absorptiometry. Bioelectric resistance, reactance, phase angle, and vector length were assessed by bioelectric impedance spectroscopy, and the BIVA procedure was applied. Results: A significant (p < 0.05) group x time interaction for fat mass, specific resistance, reactance, and vector length was found. Fat mass and vector length significantly (p < 0.05) decreased in the intervention group, while no change was measured in the control group. Considering the participants as a whole group, changes in vector length were associated with changes in fat mass percentage (r2 = 0.246; β = 0.33; p < 0.001) even after adjusting for age, sex, and group (R2 = 0.373; β = 0.23; p = 0.002). Conclusions: The specific BIVA approach is suitable to track fat mass changes during an intervention program aimed to reduce body fat in former athletes.

Association of Drug Application and Hydration Status in Elderly Patients.

Due to multifactorial reasons, such as decreased thirst and decreased total body water, elderly patients are vulnerable to dehydration. Mild cognitive impairment (MCI) or dementia increase the risk of dehydration and, in turn, dehydration decreases cognitive performance. The study aims to identify and assess differences in hydration status, taking into account patients’ drug treatment and diseases, using bioelectrical impedance vector analysis (BIVA), thereby revealing unfavorable aspects of prognosis. 447 geriatric patients (241 women, 206 men) including information on medication and bioelectrical impedance analysis (BIA) were investigated, which allowed studying the association between 40 drugs and the hydration status. First, patients were divided into disease groups. Renal disease and diuretic treatment were significantly different in both sexes, whereas cardiovascular patients differed exclusively for females. Next, drug enrichment was examined in either hyperhydrated or dehydrated patients. Simvastatin, candesartan, bisoprolol, amlodipine, olmesartan, furosemide, torasemide, allopurinol, mirtazapine, pantoprazole, cholecalciferol, and resveratrol showed enrichment depending on hydration status. This study demonstrated that patients can be differentiated and stratified by BIVA, taking into account medication and disease associated with hydration status. Although patients diagnosed with MCI and therefore treated with resveratrol, BIVA still showed evaluated dehydration. This is unfavorable in terms of prognosis and requires special attention.

Bioimpedance Vector Patterns according to Age and Handgrip Strength in Adolescent Male and Female Athletes.

Bioelectric Impedance Vector Analysis (BIVA) can be used to qualitatively compare individuals’ hydration and cell mass independently of predictive equations. This study aimed to analyze the efficiency of BIVA considering chronological age and handgrip strength in adolescent athletes. A total of 273 adolescents (male; 59%) engaged in different sports were evaluated. Bioelectrical impedance (Z), resistance (R), reactance (Xc), and phase angle (PhA) were obtained using a single-frequency bioelectrical impedance analyzer. Fat-free mass (FFM) and total body water were estimated using bioimpedance-based equations specific for adolescents. Female showed higher values of R (5.5%, p = 0.001), R/height (3.8%, p = 0.041), Z (5.3%, p = 0.001), and fat mass (53.9%, p = 0.001) than male adolescents. Male adolescents showed higher values of FFM (5.3%, p = 0.021) and PhA (3.1%, p = 0.033) than female adolescents. In both stratifications, adolescents (older > 13 years or stronger > median value) shifted to the left on the R-Xc graph, showing patterns of higher hydration and cell mass. The discrimination of subjects older than 13 years and having higher median of handgrip strength values was possibly due to maturity differences. This study showed that BIVA identified age and strength influence in vector displacement, assessing qualitative information and offering patterns of vector distribution in adolescent athletes.

Body Composition Symmetry in Long-Term Active Middle-Aged and Older Individuals.

This study aimed to analyze body composition and strength symmetry in a sample of 165 middle-aged and elderly Italian volunteers, which included 97 active (67 men and 30 women; 61.17 ± 7.56 years) individuals regularly engaged in Tai Chi Chuan, tennis, or running, and a control group of 59 age-matched sedentary (27 men and 32 women) individuals. Anthropometric and bioelectrical measurements and hand grip strength of both sides were collected. Segmental body composition was analyzed through specific bioelectrical impedance vector analysis. The body composition of the right and left limbs was similar among active individuals (arms: T2 = 6.3, n.s.; legs: T2 = 5.0, n.s.), with a similar pattern in the three different disciplines. By contrast, the control group showed bilateral asymmetry (arms: T2 = 6.8, p < 0.001; legs: T2 = 8.8, p < 0.001), mainly because of the higher values of specific reactance (t = 2.4; p = 0.018) and phase angle (t = 2.0; p = 0.054) in the dominant arm, and the higher specific vector length (t = −3.0; p = 0.027) in the left leg. All of the groups showed a higher hand grip strength in the dominant arm (active: t = 7.0, p < 0.001; control: t = 2.9; p < 0.01). In conclusion, the active individuals showed stronger body composition symmetry than the controls, thus indicating a previously undetected positive effect of sport in middle-aged and older adults.

Is bioelectrical impedance vector analysis a good indicator of nutritional status in children and adolescents?

The study objective is to propose bioelectrical impedance vector analysis (BIVA) ellipses for the population and investigate its use to assess nutritional status through the BMI/age ratio and the cardiovascular risk through waist circumference (WC). Age, weight, height and WC were recorded, along with the values of resistance (R), reactance (Xc) and phase angle (PA) by impedance. Student's t test and ANOVA were applied to ascertain the significance between means and a specific programme was applied to investigate the significance between ellipses. Fortaleza, Brazil. A total of 467 students from public schools participated in the study: 120 children and 347 adolescents were evaluated, with respective means of age, weight and height of 8·2 years, 27·6 kg and 1·29 m and 12·7 years, 48·6 kg and 1·53 m, respectively. The mean values of R/H, Xc/H and PA were 569·0 and 424·7 Ohm/m, 59·1 and 50·4 Ohm/m, and 5·9º and 6·8º for children and adolescents, respectively. The mean vectors for R/H and Xc/H show significant differences between for both age ranges and are inversely proportional to the BMI/A. As for WC, individuals without cardiovascular risk had higher R/H and lower Xc/H, but Xc and R in participants without cardiovascular risk were greater than with cardiovascular risk. It was possible to propose confidence and tolerance BIVA ellipses for children and adolescent's clinical evaluation. The method was also suitable to identify cardiovascular risk ellipses in these age groups, but it was not possible to draw nutritional classifications ellipses by BMI/age data.