Phase Angle From Bioelectrical Impedance Analysis: Population Reference Values by Age, Sex, and Body Mass Index

Phase Angle and Frailty Are Important Prognostic Factors in Critically Ill Medical Patients: A Prospective Cohort Study

OBJECTIVES

To investigate whether phase angle (PhA) measured by bioelectrical impedance analysis (BIA) and frailty are associated with the outcomes of critical illnesses.

DESIGN

A single-center prospective cohort study.

SETTING

Medical intensive care unit (ICU) in Seoul National University Hospital, Seoul, Republic of Korea.

PARTICIPANTS

97 patients who were admitted to the medical ICU.

MEASUREMENTS

On admission, PhA was measured by BIA, and frailty was assessed by the Korean Modified Barthel Index (KMBI) scoring system. Patients were classified according to PhA and KMBI scores, and their impact on the outcomes of critical illnesses was evaluated.

RESULTS

The patients' mean age was 62.4 ± 16.4 years, and 56 of the patients (57.7%) were men. Having a high PhA above 3.5 at the time of ICU admission was associated with lower in-hospital mortality (adjusted OR 0.42, p = .042), and a shorter duration of ICU stay (5.6 days vs. 9.8 days, p = .016) compared to those with a low PhA. Other indices measured by BIA were not significantly associated with outcomes of critical illnesses. Frailty (KMBI > 60) was associated with more mechanical ventilation days (2.3 days vs. 7.1 days; p = .018).

CONCLUSION

Both PhA and frailty are important prognostic factors predicting the outcomes of critical illnesses. Low PhA scores were associated with increased mortality and a longer duration of ICU stay, and frailty was associated with more mechanical ventilation days.

Bioimpedance phase angle in elite male athletes: a segmental approach

OBJECTIVE

Phase angle (PA), a bioelectrical impedance analysis (BIA) parameter, has proven to be a proxy of body cell mass in athletes, but very few data are available on its segmental evaluation (upper and lower limbs). Therefore, we aimed to assess whether whole-body and segmental PA varied among elite male athletes of different sports and compared these to control groups. Additionally, we investigated its relationship with anthropometric and body composition parameters.

APPROACH

Elite athletes practicing cycling, water polo and ballet dance aged 18-40 years underwent anthropometric and BIA measurements. PA (whole-body and upper and lower limbs) was considered as raw BIA variable. Data were also compared with healthy subjects with similar characteristics who served as control groups.

MAIN RESULTS

Participants included three groups of male athletes: 18 cyclists (age 28.6 ± 3.4 years; weight 70.6 ± 5.4 kg; BMI 21.5 ± 1.4 kg m²), 20 water polo players (age 23.9 ± 4 years; weight 89.0 ± 5.2 kg; BMI 25.9 ± 1.9 kg m²) and 18 ballet dancers (age 19.2 ± 1.3 years; weight 63.3 ± 5.8 kg; BMI 20.8 ± 1.0 kg m²) and three groups of healthy control subjects each of which similar for general characteristics (one to one) to the previous ones. Both whole-body and limb PAs were significantly higher in athletes compared to their respective controls, whereas no differences were found among sport groups. PA was positively correlated with BMI and fat-free mass (FFM) more in athletes than in controls and FFM was the main determinant.

SIGNIFICANCE

PA may represent a useful proxy parameter of soft tissue mass quality, directly related to physical activity level. Furthermore, the direct evaluation of segmental PA among athletes practicing different sports may be useful for assessing and monitoring the differences among athletes and changes due to training.

Validation of GLIM malnutrition criteria for diagnosis of malnutrition in ICU patients: An observational study

BACKGROUND & AIMS

Patients in the Intensive Care Unit (ICU) are at high risk of malnutrition. The only validated malnutrition assessment tool is the Subjective Global Assessment (SGA). The Global Leadership Initiative on Malnutrition (GLIM) is a new malnutrition assessment tool. The present study compares the nutrition-related parameters of the following tools: GLIM tool, SGA, Phase Angle (PA), Low Fat-Free Mass Index (FFMI), and Patient- and Nutrition-Derived Outcome Risk Assessment score (PANDORA), in an attempt to validate an objective tool.

METHODS

Eighty-four ICU patients were included. The tools mentioned above were assessed for their validity in diagnosing malnutrition. All patients were defined as suffering from acute disease and received medical nutrition therapy. To evaluate whether there is a correlation between the GLIM criteria, SGA, PA, and low FFMI, we compared the SGA, PA, and low FFMI to the GLIM criteria using Spearman correlation coefficients and a Chi-square test. Also, a Mann-Whitney U test was used to test the mean differences between the GLIM criteria and the PANDORA. The area under the curve (AUC) of the proposed parameters was evaluated for diagnosis of malnutrition to seek cutoff points that yield good sensitivity and specificity.

RESULTS

Mean age was 50 ± 20 years, BMI 25.3 ± 5.1 kg/m², APACHE II 20.5 ± 7.7, PANDORA score 32 ± 8.5. GLIM malnutrition criteria were significantly correlated with the gold standard SGA assessment and with low FFMI, with PA (Phase Angle), and with the PANDORA score. The area under the curve, by using the ROC curve analysis for GLIM criteria stratified by the SGA results, was 0.85 (P < 0.001). Sensitivity was 85%, and specificity 79%. However, when comparing the low FFMI, PA, and PANDORA to the GLIM criteria, the ROC curve analysis results were considered poor rank.

CONCLUSIONS

The SGA malnutrition assessment highly validated the GLIM criteria framework combined with the two-criteria diagnosis of malnutrition with a high level of precision. The GLIM malnutrition assessment seems to be acceptable in the ICU setting.

Relationship between Phase Angle and Objective and Subjective Indicators of Nutritional Status in Cancer Patients: A Systematic Review

To investigate the relationship between phase angle (PA) and objective and subjective indicators of nutritional status in cancer patients, as well as to identify cutoff points for PA, to detect malnutrition in these patients. The study was a systematic review, carried out following the guidelines of the Preferred Reporting Items for Systematic Reviews and meta-analyses (PRISMA). Literature search was performed for two authors, in indexed databases, including the National Library of Medicine, Bethesda, MD (PubMed), Latin American and Caribbean Literature in Health Sciences (LILACS), and Scopus (Elsevier). We used the checklist from the Joanna Briggs Institute for assessing the risk of bias. The review was registered with the Systematic Review Registration (PROSPERO), number CRD42020134324. In total, nine papers were eligible. PA was correlated with several objective and subjective indicators of nutritional status in most cases. Cutoff point values for the PA, capable of detecting malnutrition, varied from 4.73° to 6°, despite the modest diagnostic accuracy. We assume that PA may be considered an indicator of nutritional status, when complementing additional data and assisting health practitioners in evaluating individuals with malignant neoplasms. However, a single cutoff point with fair and concomitant sensitivity and specificity was not identified.

Phase angle and non-alcoholic fatty liver disease before and after bariatric surgery

BACKGROUND

Obesity is a global health problem that is continuing to increase in the young population. In Brazil, the frequency of obesity in 2018 was 19.8%. Several comorbidities are directly associated with obesity, such as non-alcoholic fatty liver disease (NAFLD), which is considered the most common liver disorder in Western countries and affects up to 46% of adults. Bariatric surgery is effective in treating obesity and can improve NAFLD; however, the effect of bariatric surgery on body composition, phase angle (PA), and improving NAFLD needs to be further studied.

AIM

To analyze the PA in the postoperative period of bariatric surgery and to correlate it with changes in body composition and liver disease.

METHODS

This study is a retrospective cohort study of the analysis of the medical records of patients undergoing bariatric surgery in a reference center of a teaching hospital in Porto Alegre over a 2-year period. Patients older than 18 years whose record contained all information relevant to the study were included. The data analyzed were body composition and PA through electrical bioimpedance and NAFLD through liver biopsy in the pre- and postoperative period. The level of significance adopted for the statistical analyses was 5%.

RESULTS

We evaluated 379 patients with preoperative data. Regarding PA, 169 patients were analyzed, and 33 patients had liver biopsy pre- and postoperatively with NAFLD information. In total, 79.4% were female, with a mean age of 39.1 ± 10.6 years. The average body mass index (BMI) was 45.9 ± 7.5 kg/m². The PA showed a mean of 5.8 ± 0.62° in the preoperative period and a significant reduction in the postoperative period. A postoperative reduction in body composition data (skeletal muscle mass, fat percentage, fat mass, body cell mass, BMI and visceral fat area) was shown as well. Regarding liver disease, all patients presented a reduction in the degrees and stages of liver disease in the postoperative period, and some had no degree of liver disease at all.

CONCLUSION

PA decreased after bariatric surgery, with a direct correlation with weight loss and changes in body composition. The decrease in PA was not correlated with the improvement in NAFLD.

Body Composition Post Pediatric Liver Transplant: Implications and Assessment

Liver disease has a negative influence on growth and development of children. Measurement of body composition as a component of nutrition status assessment in children before and after transplant would facilitate tailoring of nutrition therapy. A comprehensive literature search on pediatric liver transplant and body composition assessment was performed using a modified systematic approach. This review includes evidence specific to body composition of children undergoing liver transplant and a discussion of relevant body composition assessment methods for this population. Malnutrition is commonly seen in children with liver disease prior to transplant because of the disrupted metabolic pathways from liver dysfunction; however, malnutrition is not consistently diagnosed. Within 1 year of transplant, children tend to quickly recover with weight gain and linear growth. In some children, obesity and sarcopenia have been observed as long-term posttransplant outcomes. Body composition assessment tools have been utilized in diagnosing nutrition status in adults; yet there are limited studies that use these tools in the pediatric liver-transplant population. Technologies available to assess body composition include air displacement plethysmography, dual-energy x-ray absorptiometry, bioimpedance, and ultrasound. Total body potassium has been used for body composition assessment in adults and children post liver transplant; however, this method is not applicable in a clinical setting. We conclude that understanding posttransplant body composition could help clinicians diagnose and treat malnutrition.

The Predictive Role of Raw Bioelectrical Impedance Variables in Disordered Eating Attitudes in Female Ballet Dance Students

The present study used receiver operating characteristic (ROC) curve analysis to investigate the accuracy of body composition and raw bioelectrical impedance analysis (BIA) in correctly classifying disordered eating attitudes (DEA) in dance students. Participants were 81 female dancers assigned in two groups: beginner training (BT; age (mean ± SD) = 10.09 ± 1.2 years, n = 32) and advanced training (AT; age = 15.37 ± 2.1 years, n = 49). Fat mass (FM) was estimated by Slaughter's equation and skeletal muscle with Poortman's equation. Impedance (Z), resistance (R), reactance (Xc) and phase angle (PhA) were obtained through multifrequency BIA at a frequency of 50 kHz. Fat-free mass (FFM) was assessed using Sun's equation. For evaluation of DEA, the Eating Attitudes Test-26 (EAT-26) questionnaire was performed. We defined an EAT-26 score ≥ 20 as positive for DEA. Comparisons between groups were performed by a one-way ANOVA test or Kruskall-Wallis test. Spearman's rank correlation coefficients were performed to assess associations between variables. ROC curve analysis was utilized to test the accuracy of body composition and BIA variables in predicting DEA. In the BT group, Xc and PhA demonstrated high accuracy in predicting DEA with an area under the curve (AUC) of 0.976 (95% confidence interval (CI): 0.85-1.00) and 0.957 (95% CI: 0.82-0.99), respectively, (both p < 0.0001). FFM Sun had an AUC of 0.836 (95% CI: 0.66-0.94) (p < 0.0001) in the BT group and FFM Slaughter was 0.797 (95% CI: 0.66-0.90) (p < 0.001) in the AT group. Reactance and Phase angle were excellent and useful predictors of DEA in the BT group.

Bioelectrical impedance analysis (BIA) -derived phase angle in sarcopenia: A systematic review

BACKGROUND & AIMS

Bioelectrical impedance analysis-derived phase angle (PhA) has been gaining attention in the clinical evaluation of nutritional status because it is thought to be a proxy of water distribution and body cell mass; it is also associated to muscle strength and is an effective predictor of different clinical outcomes. Since an association may be expected between PhA and sarcopenia (defined by low skeletal muscle mass and impaired muscle function), the aim of this systematic review was to evaluate: a) changes in PhA due to sarcopenia; b) prevalence of sarcopenia according to PhA values; c) derivation of phase angle cut-offs for detecting sarcopenia; d) sarcopenia and PhA as predictors of clinical outcomes.

METHODS

A systematic research on electronic databases (PubMed, Embase, Scopus and Web of Science) from inception to January 31st, 2020 was performed according to PRISMA checklist. Using PICOS strategy, "P" corresponded to participants of any age, gender or ethnicity, "I" designated diagnosis of sarcopenia, "C" indicated subjects without sarcopenia, "O" corresponded to PhA, and "S" selected all study types. Methodological quality was assessed using the National Institute of Health (NIH) quality assessment tool.

RESULTS

Through the initial literature search and after removing duplicates and excluding papers by screening titles and abstracts, 79 potentially relevant studies were examined. Thirteen studies (7668 subjects) met the inclusion criteria. The overall risk of bias was low. Sarcopenia was associated with a significant lower PhA in seven studies out of eight, while five studies out of six reported a high prevalence of sarcopenia was in patients with low PhA. Different cut-off point values from 4.05 to 5.05° have been derived for the identification of sarcopenia. PhA and sarcopenia were independent predictors of survival in cancer patients and geriatric hospitalized patients.

CONCLUSIONS

Data from the selected papers demonstrate that PhA is decreased in sarcopenic subjects and the prevalence of sarcopenia is higher in subjects with low PhA. Further studies are needed to determine to what extent PhA may be valuable in detecting low muscle quality and/or identifying sarcopenia.

Heritability and Environmental Correlation of Phase Angle with Anthropometric Measurements: A Twin Study

Bioelectrical impedance analysis (BIA)-derived phase angle (PhA) is a valuable parameter to assess physical health. However, the genetic and environmental aspects of PhA are not yet well understood. The present study aimed to estimate the heritability of PhA and investigate the relationships between PhA and anthropometric measurements. PhA and skeletal muscle mass index (SMI) were examined using multi-frequency BIA in 168 Japanese twin volunteers (54 males and 114 females; mean age = 61.0 ± 16.5 years). We estimated the narrow-sense heritability of these parameters and the genetic and environmental relationships between them using a genetic twin modeling. For the PhA, 51% (95% confidence interval: 0.33, 0.64) of the variance was explained by additive genetic effects, and 49% (95% confidence interval: 0.36, 0.67) was explained by unique environmental effects. The heritability of PhA was lower than the height, body weight, and body mass index. PhA shared almost no genetic variation with anthropometric measurements and SMI but shared an environmental variation (14%) with SMI. These findings suggest that the genes affecting PhA are different than those affecting anthropometric measurements and SMI. The correlation between PhA and SMI is caused by common environmental factors.

The clinical use of longitudinal bio-electrical impedance vector analysis in assessing stabilization of children with severe acute malnutrition

BACKGROUND & AIMS

Severe Acute Malnutrition (SAM) in children is determined using anthropometry. However, bio-electrical impedance (BI) analysis could improve the estimation of altered body composition linked to edema and/or loss of lean body mass in children with SAM. We aimed to assess: 1) the changes in BI parameters during clinical stabilization and 2) whether BI parameters add prognostic value for clinical outcome beyond the use of anthropometry.

METHODS

This prospective observational study enrolled children, aged 6-60 months, that were admitted at Queen Elizabeth Central Hospital in Blantyre, Malawi, for complicated SAM (i.e., having either severe wasting or edematous SAM with a complicating illness). Height, weight, mid-upper arm circumference (MUAC), and BI were measured on admission and after clinical stabilization. BI measures were derived from height-adjusted indices of resistance (R/H), reactance (Xc/H), and phase angle (PA) and considered to reflect body fluids and soft tissue in BI vector analysis (BIVA).

RESULTS

We studied 183 children with SAM (55% edematous; age 23.0 ± 12.0 months; 54% male) and 42 community participants (age 20.1 ± 12.3 months; male 62%). Compared to community participants, the BIVA of children with edematous SAM were short with low PA and positioned low on the hydration axis which reflects severe fluid retention. In contrast, children with severe wasting had elongated vectors with a PA that was higher than children with edematous SAM but lower than community participants. Their BIVA position fell within the top right quadrant linked to leanness and dehydration. BIVA from severely wasted and edematous SAM patients differed between groups and from community children both at admission and after stabilization (p < 0.001). Vector position shifted during treatment only in children with edematous SAM (p < 0.001) and showed a upward translation suggestive of fluid loss. While PA was lower in children with SAM, PA did not contribute more than anthropometry alone towards explaining mortality, length of stay, or time-to-discharge or time-to-mortality. The variability and heterogeneity in BI measures was high and their overall added predictive value for prognosis of individual children was low.

CONCLUSIONS

BIVA did not add prognostic value over using anthropometry alone to predict clinical outcome. Several implementation challenges need to be optimized. Thus, in low-resource settings, the routine use of BI in the management of pediatric malnutrition is questionable without improved implementation.

Prospective study on sedentary behaviour patterns and changes in body composition parameters in older women: A compositional and isotemporal substitution analysis

BACKGROUND & AIMS

The aims of this study were to examine the prospective compositional associations between sedentary behaviour (SB) patterns and longitudinal changes in body composition parameters, and to use compositional isotemporal substitution modelling to analyse the longitudinal changes in body composition parameters associated with time reallocation from SB to physical activity (PA) in older women.

METHODS

The study included women aged 60 years and older (n = 182) with valid data at baseline and at the subsequent 7-year follow-up. For both time points, the ActiGraph GT1M accelerometer was used for SB and PA assessments and multi-frequency bioimpedance analysis was used to assess the body composition parameters related to adiposity and muscle mass. Compositional regression models were used to analyse the associations between proportion of time spent in sedentary bouts of different duration and longitudinal changes in body composition parameters. A compositional isotemporal substitution model was created to estimate the differences in body composition parameters associated with one-to-one time reallocations between baseline SB and PA.

RESULTS

A significant increase in fat mass index (β_ilr1 = 0.61, 95% confidence interval [CI]: 0.18, 1.04) and visceral adipose tissue (β_ilr1 = 6.01, 95% CI: 1.52, 10.5) was associated with a higher baseline proportion of time spent in long sedentary bouts (i.e. sedentary bout of ≥30 min). Reallocating 1 h/week and 3.5 h/week from the time spent in long sedentary bouts in favour of light PA was associated with a significant decrease in fat mass index by 0.78% (95% CI: 0.24, 1.32) and 3.13% (95% CI: 0.97, 5.29), respectively. No association was found for indicators of muscle mass.

CONCLUSIONS

This study suggests that long-term adiposity status could be improved by increasing the proportion of time spent in light PA at the expense of time spent in prolonged SB. This finding may help in designing more effective and feasible interventions for the maintenance of healthy body composition in advanced age.

Phase Angle Is an Independent Predictor of 6-Month Mortality in Patients With Decompensated Cirrhosis: A Prospective Cohort Study

BACKGROUND

This study aimed to evaluate the nutrition status through phase angle (PA) and its association with mortality in patients with decompensated cirrhosis.

METHODS

A prospective cohort study was performed with hospitalized decompensated cirrhotic patients. Nutrition status was assessed by PA, bioelectrical impedance vector analysis (BIVA), and Subjective Global Assessment (SGA) within 72 hours of hospital admission. The best PA cutoff point for malnutrition diagnosis was determined by ROC curve analysis, considering the SGA as the reference standard. Predictors of 6-month mortality were identified using Cox proportional hazards models, adjusted for Child-Pugh and MELD scores, and hepatocellular carcinoma.

RESULTS

This study included 97 patients, 63% male (n = 61), with a mean age of 60.1 ± 10.3 years. The median follow-up time of patients was 11.2 months (IQR, 2.4-21). Overall mortality was 58.8% (n = 57) and 6-month mortality was 35.1% (n = 34). Nutrition assessment according to BIVA indicated a risk for cachexia and normal hydration. Patients with values of PA ≤5.52° were considered malnourished. Malnourished patients according to PA (58.8%, n = 57) had a higher risk of 6-month mortality (HR = 3.44; 95% CI, 1.51-7.84; P = .003), and each increase of 1° in PA values was associated with a reduction of 53% in 6-month mortality risk.

CONCLUSIONS

The PA is an independent predictor of 6-month mortality in patients with decompensated cirrhosis. Therefore, PA may be useful to assess the nutrition status and identify patients at the highest risk of mortality in clinical practice.

Changes in the bioelectrical impedance parameters estimating appendicular skeletal muscle mass in healthy older persons

BACKGROUND AND AIMS

As population ageing, it is necessary to use inexpensive and widely available methods of monitoring healthy ageing to earlier detect the risk of potential ageing-related diseases. As an alternative to the reference methods, bioelectrical impedance analysis (BIA) enables one to quickly and easily estimate appendicular skeletal muscle mass, which in the case of older persons is an indicator of their physical fitness. The aim of this study was to evaluate the actual bio-impedance parameters used to estimate body composition, as possible markers of changes in the mass of the appendicular skeletal muscles in the course of ageing.

METHODS

Four hundred and thirty-five persons (including 107 men and 328 women) aged 50-87 years (65.6 ± 6.4 years) participated in the study. Anthropometric measurements and measurements of the bioelectrical impedance components (resistance, reactance, and phase angle) were carried out. Using the prediction equations, appendicular muscle mass and appendicular skeletal muscle mass were estimated.

RESULTS

Differences in the bio-impedance parameters between older persons aged 65 + and persons on average 10 years younger have been demonstrated and the impedance components have been shown to be correlated with age, the correlations being stronger in the persons after the 65th year of life.

CONCLUSIONS

The actual bioelectrical impedance parameters measured directly using the BIA method of estimating body composition are good identifiers of the changes in the mass of the appendicular skeletal muscles in older persons in the course of ageing.

Obesity Affects the Association of Bioelectrical Impedance Phase Angle With Mortality in People Living With HIV

Bioelectrical impedance analysis phase angle (BIA-PA) is a valid indicator of mortality risk in people living with HIV; however, it is not known whether BIA-PA is valid for people living with HIV who are overweight or obese. We assessed whether BIA-PA differentially predicted mortality by body mass index category in participants receiving clinical care at a single site between 2000 and 2012. Change in BIA-PA from the highest versus last available phase angle was assessed using multivariate logistic regression models. Eight hundred ninety participants were included in the final analyses, with 102 deaths recorded during the study period. Decline in BIA-PA was associated with mortality in underweight and normal weight participants but not in overweight or obese participants. Additional investigation is warranted to determine the appropriate clinical BIA-PA equations and parameters to identify overweight and obese patients with increased mortality risk.

Dual-frequency bioelectrical phase angle to estimate the platelet count for the prognosis of dengue fever in Indian children

A noninvasive investigation to ascertain the platelet (PLT) count was conducted on 44 hospitalized dengue hemorrhagic fever (DHF) subjects, male and female aged between 3 and 14 years using bioelectrical phase angle (BPhA). Among the 44 subjects, 30 subjects were confirmed to be non-structural protein-1 (NS1) positive at the time of admission, whose blood investigations such as hematocrit (HCT) level, PLT count, aspartate aminotransferase (AST) level and alanine aminotransferase (ALT) level were performed for the classification of risk as low-risk (LR) and high-risk (HR) DHF. It was found that the BPhA of the body reflects a linear correlation with the PLT count. To provide a better and more accurate estimate of PLT, a dual-frequency method is proposed to calculate the phase angle of the total body. The resistance at 5 kHz and reactance at 100 kHz were used to estimate the phase angle of the total body. The statistical analysis identified that the PLT count estimated using the proposed dual-frequency method shows a good correlation with the blood investigation results. In addition, statistical analysis of the proposed method on other fever subjects indicated a significant difference with DHF.

The Effect of Probiotic Yogurt Containing Lactobacillus Acidophilus LA-5 and Bifidobacterium Lactis BB-12 on Selected Anthropometric Parameters in Obese Individuals on an Energy-Restricted Diet: A Randomized, Controlled Trial

Previous studies using probiotics have shown strain-dependent effects on body mass index (BMI), body mass, or fat mass (FM). The aim of this study was to evaluate how the addition of yogurt containing Lactobacillus acidophilus LA-5 and Bifidobacterium animalis subsp. lactis BB-12 strains to a diet plan affects selected anthropometric parameters in obese people on an energy-restricted diet. Fifty-four subjects aged 20–49 (34.52 ± 9.58) years were included in this study. The recruited subjects were assigned to two subgroups: consuming probiotic yogurt along with a hypocaloric diet (GP) (n–27) or the same diet but without an intentional introduction of yogurt (GRD) (n–27) for 12 weeks. Both GP and GRD decreased body weight, BMI, fat mass and visceral fat by 5.59 kg and 4.71 kg, 1.89 and 1.61 kg/m2, 4.80 kg and 4.07 kg, and 0.68 and 0.65 L, respectively, although the obtained differences were not significant. Analysis of GP and GRD results separately at the beginning and end of the intervention showed that fat loss was substantial in both groups (p < 0.05). Consumption of yogurt containing LA-5 and BB-12 does not significantly improve anthropometric parameters in obese patients.

Interpopulation Similarity of Sex and Age-Related Body Composition Variations Among Older Adults

The aim of the study was to analyze sex and age-related body composition variations among older adults from the Brazilian, Italian, and Mexican population. A cross-sectional analysis was conducted in 1103 community-dwelling older adults (634 women and 469 men), aged 60 to 89 years, living in Brazil (n = 176), Italy (n = 554), and Mexico (n = 373). Anthropometric measurements were taken, BMI was calculated, and impedance measurements were obtained (resistance, R, reactance, Xc). Specific bioelectrical impedance vector analysis (specific BIVA) was applied, with the specific vector defined by impedance, or vector length (Z = (Rsp² + Xcsp)^0.5), and phase angle (PA = arctan Xc/R 180/π). Population, sex, and age differences in anthropometric and bioelectrical variables were evaluated by means of a two way ANOVA. The mean bioelectrical vectors were graphed by confidence ellipses and statistically compared by the Hotelling's T² test. The three population groups showed differences in body mass and composition (p < 0.001): the Brazilian sample was characterized by greater body dimensions, longer vectors (higher relative content of fat mass), and lower phase angles (lower skeletal muscle mass). Men were taller and heavier than women (p < 0.001) but had a similar BMI (p = 0.102). They also had higher phase angle (higher skeletal muscle mass) (p < 0.001) and lower vector length (lower %FM) (p < 0.001). In the three population groups, the oldest individuals showed lower anthropometric and phase angle values with respect to the youngest ones (p < 0.001), whereas the vector length did not change significantly with age (p = 0.665). Despite the differences between sexes and among populations, the trend of age-related variations was similar in the Brazilian, Italian, and Mexican older adults.

Effects of Resistance Training with Different Pyramid Systems on Bioimpedance Vector Patterns, Body Composition, and Cellular Health in Older Women: A Randomized Controlled Trial

Bioelectrical impedance vector analysis (BIVA) and phase angle (PhA) have been widely used to monitor changes in health-related parameters in older adults, while resistance training (RT) is one of the potential strategies to mitigate the adverse effects of aging. The purpose of this study was to compare the effects of the crescent pyramid RT system with two repetition zones on BIVA patterns and PhA. Fifty-five older women (≥60 years) were randomly assigned into three groups: control (CON, n = 18), narrow pyramid (NPR, n = 19), and wide pyramid (WPR, n = 18). The RT was performed for eight weeks, three times per week, in eight exercises for the whole body with three sets of 12/10/8 (NPR) or 15/10/5 repetitions (WPR). Bioimpedance spectroscopy (50 kHz frequency) was assessed. After the intervention period, both training groups showed significant changes in BIVA patterns compared to CON (p < 0.001); resistance decreased and reactance increased, which resulted in a BIVA-vector displacement over time (p < 0.001). Changes in PhA were greater for WPR (∆% = 10.6; effect size [ES] = 0.64) compared to NPR (∆% = 5.3; ES = 0.41) and CON (∆% = −6.4; ES = −0.40). The results suggest that the crescent pyramid RT system with both repetition zones (WPR and NPR) is effective for inducing improvements in BIVA patterns and PhA in older women, although WPR elicits greater increases in PhA than NPR.

Independent Association of Phase Angle with Fasting Blood Glucose and Hemoglobin A1c in Korean Type 2 Diabetes Patients

The relationship between phase angle (PhA) of bioelectrical impedance analysis (BIA) and glycemic parameters in diabetes mellitus (DM) patients has not been well studied. To evaluate the prognostic value of the PhA from BIA as a glycemic marker, we investigated the relationship of PhA with various variables such as age, body mass index (BMI), and glycemic parameters in Korean patients with type 2 DM (T2DM). We evaluated the anthropometric data, body composition, glycemic parameters, and PhA of 321 T2DM patients aged 30–83 years. The patients were classified by sex into men (n = 133) and women (n = 188). General linear models identified the independent effects of PhA after covarying for age, sex and BMI. The PhA, body cell mass (BCM), extracellular mass (ECM), lean body mass, intracellular water (ICW), extracellular water (ECW), total body water (TBW), fasting blood glucose, and hemoglobin A1c (HbA1c) of T2DM Korean patients were significantly higher in men than in women. However, fat mass, ECM/BCM, ECW/ICW, ECW/TBW, and serum insulin were significantly higher in women than in men. Statistically significant independent associations were observed between PhA and age, BCM, ECM, ECM/BCM, ICW, ECW, ECW/ICW, and ECW/TBW for both sexes. There was no significant association between PhA and BMI the patients. Glycemic parameters, such as HbA1c and fasting blood glucose were independently associated with PhA. These results suggest that PhA could be an indicator for assessing ability to control fasting blood glucose in T2DM patients in Korea.

Phase Angle Evaluation of Lung Disease Patients and Its Relationship with Nutritional and Functional Parameters

BACKGROUND

This study aimed to determine the value of phase angle (PhA) in patients with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension (PH) and its association with nutritional and functional parameters.

METHODS

A cross-sectional study of 77 patients under follow-up at the pulmonary outpatient clinic of a public hospital. Anthropometric measurements and functional assessments of physical and pulmonary capacity were performed, and a regular physical activity questionnaire was administered.

RESULTS

The sample consisted of 38 patients with COPD (mean age, 63.8 ± 9.9 years; 68.4% female) and 39 patients with PH (mean age, 46.6 ± 14.4 years; 79.5% female). There was no difference in anthropometric measurements between patients with COPD and PH. Patients with COPD had mild to moderate limitations of pulmonary function, while patients with PH had only mild limitations (p < 0.01). Although the median distance covered in the 6-minute walk test (6MWT) was different between the COPD and PH groups (p < 0.05), it was considered adequate for these populations. Mean PhA was within the range considered adequate in patients with COPD (6.3°±1°) and PH (6.2°±0.8°) (p > 0.05). In the statistical analyses, although the correlations were weak, adequate PhA correlated with fat free mass index, 6MWT, disease staging, forced vital capacity, and forced expiratory volume in the first second.

CONCLUSION

The anthropometric profile of both patient groups was very similar, and PhA values were within the expected range. Despite weak correlations, PhA is a clinical component to be followed and investigated in patients with lung disease.

Phase Angle as an Indicator of Sarcopenia, Malnutrition, and Cachexia in Inpatients with Cardiovascular Diseases

Malnutrition is associated with sarcopenia, cachexia, and prognosis. We investigated the usefulness of phase angle (PhA) as a marker of sarcopenia, cachexia, and malnutrition in 412 hospitalized patients with cardiovascular disease. We analyzed body composition with bioelectrical impedance analysis, and nutritional status such as controlling nutritional status (CONUT) score. Both skeletal muscle mass index (SMI) and PhA correlated with age, grip strength and knee extension strength (p < 0.0001) in both sexes. The SMI value correlated with CONUT score, Hb, and Alb in males. Phase angle also correlated with CONUT score, Hb, and Alb in males, and more strongly associated with these nutritional aspects. In females, PhA was correlated with Hb and Alb (p < 0.001). In both sexes, sarcopenia incidence was 31.6% and 32.4%; PhA cut-off in patients with sarcopenia was 4.55° and 4.25°; and cachexia incidence was 11.5% and 14.1%, respectively. The PhA cut-off in males with cachexia was 4.15°. Multivariate regression analysis showed that grip strength and brain natriuretic peptide (BNP) were independent determinants of SMI, whereas grip strength, BNP, and Hb were independent determinants of PhA. Thus, PhA appears to be a useful marker for sarcopenia, malnutrition, and cachexia in hospitalized patients with cardiovascular disease.

Associations between Phase Angle Values Obtained by Bioelectrical Impedance Analysis and Nonalcoholic Fatty Liver Disease in an Overweight Population

OBJECTIVE

There is a limited diagnosis of nonalcoholic fatty liver disease (NAFLD). Thus, the noninvasive assessments are worth exploring. We determined the associations of phase angles (PhAs) obtained from bioelectric impedance analysis (BIA) with the risk of NAFLD in an overweight population.

METHODS

A study involving 953 overweight participants was conducted in Wuhan city, China. The associations between PhAs (right arm, left arm, body trunk, right leg, left leg, and whole body) and the risk of NAFLD were conducted using multivariate logistic regression analyses. The associations of PhAs with the controlled attenuation parameter (CAP), a noninvasive assessment of liver steatosis and fibrosis, were also evaluated by both linear and logistic regression analyses.

RESULTS

The PhA values of the whole body, trunk, and legs were significantly lower (P < 0.05) in the NAFLD group than the non-NAFLD group. After adjustment for BMI, gender, education, income/year, hyperlipidemia, hypertension, diabetes, smoking, passive smoking, and drinking, significant associations of PhA values of the right leg, left leg, and whole body with the risk of NAFLD were observed. In addition, the PhA of the right leg, left leg, and whole body were significantly related to the CAP values. Further stratified analyses indicated that these associations were significant in the participants with BMI <30, but not in the participants with BMI ≥30.

CONCLUSIONS

PhAs might be effective indicators in the management of NAFLD among overweight people.

Phase angle associated with different indicators of health-related physical fitness in adults with obesity

In obese populations, the exacerbated increase in adipose tissue results in a significant reduction of health-related physical fitness and can affect the phase angle (PhA), a promising health indicator of cell health and integrity. The aim of this study was to investigate the association of PhA with health-related physical fitness indicators in obese adults. This cross-sectional study had a non-probabilistic sample and was conducted from April to June 2018. The PhA was obtained by a bioelectrical impedance analysis, and the health-related physical fitness indicators evaluated were percentage of body fat (%BF), lower- and upper-body maximal strength, cardiorespiratory fitness (relative V̇O2peak), and flexibility. Pearson and Spearman´s linear correlations, crude and adjusted linear regression analyses were performed. A total of 69 obese adults (60.8% female; BMI = 33.5 ± 2.8 kg/m²) with a mean age of 34.6 ± 7.1 years were studied. The PhA means were 5.8 (±0.6º) and had an inverse correlation with %BF (r=-0.74; p<0.001) and positive correlation with V̇O2peak (r=0.50; p<0.001), lower- and upper-body maximal strength (r=0.65; r=0.70; p<0.001, respectively). After adjustment, %BF (β=-0.065, adjusted R²=0.53; p<0.001), lower- and upper-body maximal strength (β=0.004; adjusted R²=0.46; p<0.001, and β=0.024; adjusted R²=0.50; p<0.001, respectively) were predictors of PhA. Our results suggest the favorable role of PhA as a clinically viable tool to screen and identify the physical fitness variables and functional status of obese adults.

Phase Angle: Could Be an Easy Tool to Detect Low-Grade Systemic Inflammation in Adults Affected by Prader-Willi Syndrome?

Prader-Willi syndrome (PWS) is the most common genetic inherited obesity syndrome. Obesity-related complications, mostly related to chronic low-grade systemic inflammation (LGI), are the commonest cause of mortality and morbidity in PWS adults. Phase angle (PhA) is an easy tool to screen a state of LGI in healthy subjects and in subjects with obesity and is obtained from bioelectrical impedance analysis (BIA). The aim of this study was to validate the PhA in PWS adults as a potential biomarker of LGI. In this single-center, cross-sectional study, fifteen PWS adults (six males, aged 19-41 years, and body mass index (BMI) 31.0-68.0 Kg/m2) and fifteen control subjects matched by gender, age, and BMI were evaluated. PhA values were significantly lower (p < 0.001), while high-sensitivity C-reactive protein (hs-CRP) levels were significantly higher (p < 0.001) in PWS adults compared with controls (p < 0.001), without a gender difference in the latter. After adjustment for gender, BMI, and waist circumference, significant correlation was found between PhA and hs-CRP levels (r = -0.69, p = 0.01). At the ROC analysis, the threshold value of PhA predicting the highest hs-CRP levels above the median value was found at PhA ≤ 4.8° (p = 0.01; AUC, 0.82; standard error, 0.12; 95% CI, 0.58 to 1.00). These results suggest that PWS adults had a significant higher degree of LGI compared with their counterparts. Moreover, our finding suggest that PhA is a valid biomarker of LGI also in PWS adults.

Impact of modified short-term fasting and its combination with a fasting supportive diet during chemotherapy on the incidence and severity of chemotherapy-induced toxicities in cancer patients - a controlled cross-over pilot study

BACKGROUND

This pilot trial aimed to investigate whether modified short-term fasting (mSTF) reduces the incidence of chemotherapy-induced toxicities and whether an initial ketogenic diet (KD) as fasting supportive diet reduces fasting-related discomfort and improves the compliance.

METHODS

In this controlled cross-over trial, gynaecologic cancer patients undergoing chemotherapy with a minimum of 4 cycles fasted for 96 h during half of their chemotherapy cycles and consumed a normocaloric diet during the other chemotherapy cycles. The caloric intake during mSTF was restricted to 25% of each patient's daily requirement. In addition, half of the patients should eat a 6-day normocaloric KD prior to each mSTF period to investigate a KD's hunger-suppression effect. Chemotherapy-induced toxicities, fasting-related discomfort, body composition, quality of life, laboratory values, and compliance were assessed at each chemotherapy.

RESULTS

Thirty patients aged 30-74 years (median 54 years) completed the study. During mSTF the frequency and severity score of stomatitis [- 0.16 ± 0.06; 95% CI -0.28 - (- 0.03); P = 0.013], headaches [- 1.80 ± 0.55; 95% CI -2.89 - (- 0.71); P = 0.002], weakness [- 1.99 ± 0.87; 95% CI -3.72 - (- 0.26); P = 0.024] and the total toxicities' score were significantly reduced [- 10.36 ± 4.44; 95% CI -19.22 - (- 1.50); P = 0.023]. We also observed significantly fewer chemotherapy postponements post-mSTF, reflecting improved tolerance of chemotherapy [- 0.80 ± 0.37; 95% CI -1.53 - (- 0.06); P = 0.034]. A significant reduction in mean body weight by - 0.79 ± 1.47 kg during mSTF was not compensated and remained until study's conclusion (P < 0.005). On average, Insulin [- 169.4 ± 44.1; 95% CI -257.1 - (- 81.8); P < 0.001] and Insulin-like growth factor 1 levels [- 33.3 ± 5.4; 95% CI -44.1 - (- 22.5); P < 0.001] dropped significantly during fasting. The KD as a fasting supportive diet neither reduced fasting-related discomfort nor improved compliance of our fasting regimen.

CONCLUSION

MSTF is safe and feasible in gynaecologic cancer patients. Our results indicate that mSTF during chemotherapy can reduce chemotherapy-induced toxicities and enhance the tolerance of chemotherapy. Larger clinical trials are required to recommend mSTF for cancer patients.

TRIAL REGISTRATION

germanctr.de: DRKS00011610, registered 30 January, 2017.

Phase Angle from Bioelectric Impedance and Maturity-Related Factors in Adolescent Athletes: A Systematic Review

Phase angle (PhA) is a body composition (BC) parameter from bioelectrical impedance analysis that is suggested as a marker of cell integrity and general health. In adolescent athletes, PhA values are used to monitor the effects of training and competitions and seem to vary according to age, having an upward trajectory during puberty. Since adolescence is a period composed of maturation stages, the aim of this systematic review was to investigate the relationship between PhA and maturation stage in adolescent athletes. A search was conducted in PubMed/MEDLINE, BVS, Web of Science (WOS), Scopus, Science Direct, and Academic Search Complete (EBSCO) databases up to May 2020. Eligibility criteria followed the PICOS strategy and studies with healthy athletes aged 10–19 years of any level of competition were included. Six cross-sectional studies and two longitudinal studies met the inclusion criteria. Results showed that early and mature athletes have higher PhA than those who are non-matured or maturated late. Thus, PhA is influenced by the pubertal status. Considering BC is one of the factors influencing sports performance together with its growth-related changes, practitioners may use PhA values in BC analysis of adolescent athletes.

The efficacy of early postoperative enteral immunonutrition on T-lymphocyte count: A randomised control study in low-risk cardiac surgery patients

BACKGROUND

Patients undergoing cardiac surgery have a pronounced immune response that leads to a reduction in cellular immunity. Immune-modulating nutritional supplements are considered to be beneficial for patients undergoing major surgery. However, due to the lack of studies in the cardiac surgery population, the effect of immunonutrition remains unclear in this patient group.

OBJECTIVE

Our purpose was to research the efficacy of early postoperative enteral immunonutrition on T-lymphocyte count in the cardiac surgery population.

METHODS

This was a randomised control study of low operative risk adult patients, who underwent elective cardiac surgery. These patients were randomised into immunonutrition and control groups. The immunonutrition group was supplemented with immune nutrients for five postoperative days. The counts of T-lymphocytes, as well as the counts for the CD4+ and CD8+ cell subpopulations were determined on the day of surgery and on the sixth postoperative day.

RESULTS

Fifty-five patients were enrolled in the study, the mean age was 69.7 ± 6.3 years, 28 (50.9%) of them were males, the median operative risk was 1.75%. Twenty-seven (49.1%) were randomised into the immunonutrition group. The control and the immunonutrition groups were similar before the intervention. The counts of the CD3+ T cells and CD4+ T cells on the sixth postoperative day were significantly higher in the immunonutrition group compared to the control group with 1.42 ± 0.49 vs. 1.12 ± 0.56 (∗10⁹/l), p = 0.035 and 1.02 ± 0.36 vs. 0.80 ± 0.43 (∗10⁹/l), p = 0.048, respectively. Regression analysis was performed to determine the efficacy of the immunonutrition on the counts of the CD3+ and CD4+ T cells; CD3+ T and CD4+ T cell counts were increased to 0.264 (∗10⁹/l), p = 0.039 and 0.232 (∗10⁹/l), p = 0.021, respectively.

CONCLUSIONS

Early postoperative immunonutrition increases the count of the CD3+ and CD4+ T cells in cardiac surgical patients. Clinical trials identifier number: NCT04047095.

Prognostic Impact of Preoperative Nutritional Risk in Patients Who Undergo Surgery for Pancreatic Adenocarcinoma

BACKGROUND

Nutritional derangements are common hallmarks of pancreatic cancer (PC). Their early detection and management are usually overlooked in routine practice. This study aimed to explore preoperative nutritional status and its prognostic value in patients undergoing surgery for PC.

METHODS

Data from 73 patients who underwent surgery for PC from November 2015 to January 2018 at the General and Pancreatic Surgery Unit, The Pancreas Institute, University Hospital of Verona Hospital, Verona, Italy, were retrospectively evaluated. The Nutritional Risk Screening (NRS)-2002 was used to evaluate the preoperative nutritional risk. Body composition was assessed using bioimpedance vectorial analysis (BIVA) on the day prior to surgery. The effect of clinical, pathological, and nutritional characteristics on overall survival (OS) was investigated using a Cox and logistic regression model. Kaplan-Meier curves were compared using the log-rank test.

RESULTS

Most patients (80.8%) were at preoperative risk of malnutrition (NRS-2002 ≥ 3) despite a mean BMI of 24.1 kg/m²(± 4.3). Twenty-four patients (32.9%) received neoadjuvant therapy prior to surgery. Preoperative NRS-2002 was significantly higher in this subset of patients (p = 0.026), with a significant difference by chemotherapy regimens (in favor of FOLFIRINOX, p = 0.035). In a multivariate analysis, the only independent prognostic factor for OS was the NRS-2002 score (HR 5.24, p = 0.013). Particularly, the likelihood of 2-year survival was higher in NRS < 3 (p = 0.009).

CONCLUSIONS

Our analysis confirms that preoperative malnutrition has a detrimental impact on OS in PC patients undergoing radical surgery for PC. Careful preoperative nutritional evaluation of PC patients should be mandatory, especially in those who are candidates for neoadjuvant therapy.

Phase Angle is Determined by Body Composition and Cardiorespiratory Fitness in Adolescents

The phase angle is used to evaluate nutritional status and is an indicator of cellular health. Cardiorespiratory fitness and body composition are strong indicators of health during adolescence. We aimed to evaluate if body composition and cardiorespiratory fitness have an association with phase angle among adolescents. 203 girls and 220 boys (12.8±1.3 years) were evaluated. Peak height velocity, percentage fat mass, fat-free mass, cardiorespiratory fitness, and phase angle measurements were collected. Linear regression adjusted by peak height velocity was used to verify if predictor variables were associated with phase angle among adolescents. Phase angle showed correlation with fat-free mass (girls: r=0.42 and boys: r=0.37); with percent fat mass (girls: r=0.23); and with cardiorespiratory fitness (boys: r=0.19). Linear regression showed that percentage fat mass (in girls) and cardiorespiratory fitness (in boys) had an effect of 11 and 17% in phase angle, respectively, while fat-free mass had an effect of 22 and 26% in phase angle for girls and boys, respectively. Changes in phase angle seem to be more associated with the percentage fat mass in girls, cardiorespiratory fitness in boys, and fat-free mass in both when controlled by peak height velocity.

Phase angle as a predictor of functional outcomes in patients undergoing in-hospital rehabilitation after hip fracture surgery

OBJECTIVES

To evaluate the association between the phase angle and functional outcomes in patients after in-hospital postoperative rehabilitation for fragility hip fracture.

METHODS

A prospective observational study was conducted in 68 patients over 65 years of age who had undergone a two-week postoperative rehabilitation for hip fracture. Phase angle of the non-fractured limb was used to reduce the error caused by postoperative edema. Participants were divided into groups according to phase angle terciles. Multivariable linear regression models adjusted for relevant factors known to affect functional outcomes after hip fracture were performed to identify the association between phase angle of the non-fractured limb and functional outcomes at discharge as evaluated the Functional Ambulation Category and Berg Balance Scale.

RESULTS

The mean age of this study population was 81.9 ± 6.2 years and the average phase angle of the non-fractured limb was 3.6 ± 1.3°. The lowest tercile of phase angle (<3.0°) was independently associated with worse functional outcomes as measured by the Functional Ambulation Category and Berg Balance Scale at discharge (adjusted coefficient [β] = -0.287, P = 0.004; β = -0.172, P = 0.049, respectively) after adjusting for relevant covariates.

CONCLUSIONS

Low phase angle of the non-fractured limb was independently associated with worse functional outcomes at rehabilitation discharge in patients who undergoing hip fracture surgery. Phase angle may reflect both the pre-fracture body composition and functional status. It is a useful indicator for functional outcomes after postoperative rehabilitation for fragility hip fracture.

Perioperative Interstitial Fluid Expansion Predicts Major Morbidity Following Pancreatic Surgery: Appraisal by Bioimpedance Vector Analysis

OBJECTIVE

To evaluate whether perioperative bioimpedance vector analysis (BIVA) predicts the occurrence of surgery-related morbidity.

SUMMARY BACKGROUND DATA

BIVA is a reliable tool to assess hydration status and compartimentalized fluid distribution.

METHODS

The BIVA of patients undergoing resection for pancreatic malignancies was prospectively measured on the day prior to surgery and on postoperative day (POD)1. Postoperative morbidity was scored per the Clavien-Dindo classification (CDC), and the Comprehensive Complication Index (CCI).

RESULTS

Out of 249 patients, the overall and major complication rates were 61% and 16.5% respectively. The median CCI was 24 (IQR 0.0-24.2), and 24 patients (9.6%) had a complication burden with CCI≥40. At baseline the impedance vectors of severe complicated patients were shorter compared to the vectors of uncomplicated patients only for the female subgroup (P=0.016). The preoperative extracellular water (ECW) was significantly higher in patients who experienced severe morbidity according to the CDC or not [19.4L (17.5-22.0) vs. 18.2L (15.6-20.6), P=0.009, respectively] and CCI≥40, or not [20.3L (18.5-22.7) vs. 18.3L (15.6-20.6), P=0.002, respectively]. The hydration index on POD1 was significantly higher in patients who experienced major complications than in uncomplicated patients (P=0.020 and P=0.025 for CDC and CCI, respectively).At a linear regression model, age (β=0.14, P=0.035), sex female (β=0.40, P<0.001), BMI (β=0.30, P<0.001), and malnutrition (β=0.14, P=0.037) were independent predictors of postoperative ECW.

CONCLUSION

The amount of extracellular fluid accumulation predicts major morbidity after pancreatic surgery. Female, obese and malnourished patients were at high risk of extracellular fluid accumulation.

Methods for Detection of Bioimpedance Variations in Resource Constrained Environments

Changes in a certain parameter are often a few magnitudes smaller than the base value of the parameter, specifying significant requirements for the dynamic range and noise levels of the measurement system. In case of electrical bioimpedance acquisition, the variations can be 1000 times smaller than the entire measured value. Synchronous or lock-in measurement of these variations is discussed in the current paper, and novel measurement solutions are presented. Proposed methods are simple and robust when compared to other applicable solutions. A common feature shared by all members of the group of the proposed solutions is differentiation. It is achieved by calculating the differences between synchronously acquired consecutive samples, with lock-in integration and analog differentiation. All these methods enable inherent separation of variations from the static component of the signal. The variable component of the bioimpedance can, thus, be acquired using the full available dynamic range of the apparatus for its detection. Additive disturbing signals and omnipresent wideband noise are considered and the method for their reduction is proposed.

The prognostic value of standardized phase angle in adults with acute leukemia: A prospective study

Standardized phase angle (SPhA) is a tool used to estimate body composition and cell membrane integrity. Standardized phase angle has been shown to predict survival in solid malignancies and hematopoietic stem cell transplant patients. We investigated the predictive value of SPhA on 60-day mortality, overall survival (OS), and length of hospital stay (LHS) for adults with acute myelogenous and lymphoblastic leukemia (AML and ALL). Consecutive patients ≥18 years with newly diagnosed acute leukemia receiving intensive chemotherapy were enrolled. Phase angle measurements were taken on day 1 of therapy for all patients and on the day of nadir marrow for AML patients. Measurements were standardized by BMI, gender, and age to calculate the SPhA. The difference between SPhA at nadir bone marrow compared to day 1 of induction was used to calculate change in SPhA. A cutoff of 25th percentile was used to dichotomize baseline SPhA. Among 100 patients, 88% were AML, 56% were female, and mean age was 59 years. Though not statistically significant, OS by Kaplan-Meier analysis was shorter for those below the 25th percentile SPhA compared to those above (median OS: 11.0 months vs 19.5 months; P = .09). Lower baseline SPhA was associated with increased incidence of 60-day mortality in univariable (odds ratio [OR] = 5.25; 1.35, 20.44; P = .02) but not multivariable analysis (OR = 3.12; 0.67, 14.48; P = .15) adjusted for age, creatinine, and cytogenetics. Increased change in SPhA was associated with worse OS (hazard ratio = 1.15; 1.00,1.33; P = .05) in multivariable analysis. Standardized phase angle is a rapid, noninvasive, and objective measure that may be used to inform risk stratification.

Predictivity of bioimpedance phase angle for incident disability in older adults

BACKGROUND

Bioelectrical impedance analysis (BIA)-derived phase angle is expected to be an efficient prognostic marker of health adverse events with aging as an alternative of muscle mass. We aimed to examine the predictive ability of phase angle for incident disability in community-dwelling elderly and determine the optimal cut-off values.

METHODS

Community-dwelling elderly aged ≥65 years (n = 4452; mean age = 71.8 ± 5.3 years, 48.3% women) without disability at baseline participated in this prospective cohort study. Phase angle and appendicular skeletal muscle mass (ASM) were examined using a multi-frequency BIA at baseline. Other potential confounding factors (demographics, cognitive function, depressive symptoms, medications, and physical performance) were also assessed. Incident disability was monitored on the basis of long-term care insurance certification.

RESULTS

Over a follow-up of 24 months, 4.0% (n = 174) experienced disability, with an overall incidence rate of 20.6 per 1000 person-years. The Cox hazard regression analysis showed that phase angle, as a continuous variable, was independently associated with incident disability after adjusting the covariates [male: hazard ratios (HRs) = 0.61, 95% confidence interval (CI) = 0.37-0.98; female: HR = 0.58, 95% CI = 0.37-0.90], although body mass index adjusted ASM was not. Receiver operating characteristic analysis indicated moderate predictive abilities of phase angle for incident disability [male: area under the receiver operating characteristic curve (AUC) = 0.76, 95% CI = 0.70-0.83; female: AUC = 0.71, 95% CI = 0.65-0.76], while those of body mass index adjusted ASM were low (male: AUC = 0.59, 95% CI = 0.521-0.66; female: AUC = 0.58, 95% CI = 0.52-0.63). Multivariate Cox regression analysis showed that low phase angle categorized by cut-off value (male, ≤4.95°; female, ≤4.35°) was independently related to increased risk of incident disability (HR = 1.95, 95% CI = 1.37-2.78).

CONCLUSIONS

Lower phase angle independently predicts the incident disability separately from known risk factors. BIA-derived phase angle can be used as a valuable and simple prognostic tool to identify the elderly at risk of disability as targets of preventive treatment.

Whole body vibration training during allogeneic hematopoietic cell transplantation-the effects on patients' physical capacity

Patients undergoing allogeneic hematopoietic cell transplantation (alloHCT) experience a considerable decline in physical and psycho-social capacity. Since whole body vibration (WBV) is known to efficiently stimulate the neuromuscular system and enhance cardiorespiratory fitness and muscle strength in frail individuals, we hypothesized that WBV would maintain various physical and psychological capacities in patients during alloHCT. Seventy-one patients were randomly allocated to either an intervention group (IG) doing WBV or an active control group (CG) doing mobilization exercises five times per week. We determined peak oxygen consumption (VO_2peak) and maximum power, maximum strength, functional performance, body composition, quality of life (QoL), and fatigue. Tests were carried out before conditioning therapy, at hospital discharge and at day ± 180 (follow-up). As 18 patients did not participate in post-intervention assessment and follow-up data from 9 patients was not collectible, per-protocol (PP) analysis of 44 patients is presented. During hospitalization, WBV maintained maximum strength, height, and power output during jumping, as well as reported QoL, physical functioning, and fatigue level compared with mobilization. At follow-up, relative VO_2peak (p = 0.035) and maximum power (p = 0.011), time and power performing chair-rising test (p = 0.022; p = 0.009), and reported physical functioning (p = 0.035) significantly increased in the IG, while fatigue decreased (p = 0.005). CG’s body cell mass and phase angle had significantly decreased at follow-up (p = 0.002; p = 0.004). Thus, WBV might maintain maximum strength, functional performance, QoL, and fatigue during alloHCT, while cardiorespiratory fitness might benefit from accelerated recovery afterwards.

Phase angle could be a marker of microvascular damage in systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is an autoimmune disease characterized by endothelial dysfunction with fibrosis of skin and internal organs. Integrity of the endothelial cell is important to its physiologic function such as production of angiogenetic factors. The aim of this study was to assess whether phase angle (PhA) is altered in patients with SSc and whether its values correlate with vascular endothelial growth factor (VEGF) and digital microvascular damage.

METHODS

Patients with SSc and matched healthy controls underwent VEGF determination and bioimpedentiometry (BIA) for PhA assessment. Clinical assessment, disease activity index (DAI), disease severity scale, and nailfold videocapillaroscopy (NCV) were performed in patients with SSc.

RESULTS

Fifty-five patients (46 women) with a mean age of 53.2 ± 13.7 y were studied. The mean value of VEGF was significantly higher in patients with SSc than in the healthy controls (240.3 ± 149.5 versus 139 ± 87.5; P = 0.035). The mean value of PhA was significantly lower in the patient grouop than in the healthy controls (4.51 ± 0.87 versus 5.22 ± 0.55; P < 0.0001). A significant positive correlation was found between VEGF and PhA (P = 0.009, beta coefficient = 1.48) in SSc patients. A negative correlation between VEGF and DAI (P = 0.048, β coefficient = 0.48) was found. PhA median value was significantly (P = 0.006) lower in patients with late pattern SSc (4.2 [2.5-5.3]). PhA median value was significantly (P < 0,0001) lower in patients with digital ulcers (DUs; 4.2 [2.5-5.3]) than in those without DUs (3.80 [2.50-5] versus 4.75 [2.80-7.3]). These data were confirmed in both female and male patients.

CONCLUSIONS

The evaluation of VEGF with PhA, NVC, and DUs could be useful to estimate cellular and microvascular damage in patients with SSc.

Phase Angle Reflects Loss of Functionality in Older Women

OBJECTIVE

This study verified if the phase angle (PA) formed by the resistance (R) and reactance (Xc) obtained from bioimpedance (BIA) might be a useful tool to identify functionality.

DESIGN AND PARTICIPANTS

It was conducted a cross-sectional study with 152 women ≥ 65 years old from the community.

MEASUREMENTS

weight, height, body mass index (BMI), calf circumference (CC), hand grip strength (HGS), gait speed (GS), fat free mass (FFM), body fat (BF), PA with R and Xc from the BIA were measured. Spearman's and Pearson's correlations and the odds ratio (OR) were performed using the IBM SPSS software version 22.0.

RESULTS

Sixty-four percent (n=98) women are with PA below the reference. Negative moderate significant correlation was found between PA and age (r =- 0.440*; p<0.001). Moderate significant correlation was observed between PA and GS (r = 0.484**; p<0.001). Weak significant correlation was found between PA and HGS (r = 0.177*; p = 0.029). Odds ratio (OR) demonstrated that individuals with PA above the mean value have 4.77 times more chances of having increased GS (confidence interval 2.40-9.48; 95%). Women aged below the mean value have 4.02 times more chances of having higher PA (confidence interval 2.02-7.99; 95%). Younger aged women showed 4.02 times more chances of having higher PA (confidence interval 2.02-7.99; 95%).

CONCLUSIONS

Phase angle can be associated with functional tests, such as gait speed and hand grip strength, in older women.

WHOLE-BODY VIBRATION TRAINING PROTOCOLS IN OBESE INDIVIDUALS: A SYSTEMATIC REVIEW

ABSTRACT Obesity is a chronic degenerative disease. Whole-body vibration (WBV) devices make it possible to control the intensity of exercises through their variables: frequency, amplitude and vibration time, thus enabling interventions in these populations. The objective of this study was to review the applications, protocols and results of WBV devices in obese individuals. A systematic literature review was conducted using the descriptors and terms verified in DeCS (LILACS and SCIELO) and MeSH (PubMED). Of the thirteen studies selected, seven used an experimental and six a quasi-experimental methodological design. Eleven studies analyzed chronic responses and two studies acute responses to WBV training. Frequency values ranged between 30 and 35 Hz, amplitude was around 2 mm, and in terms of intensity, most of the training protocols used a gradual increase in WBV throughout the intervention. Eight studies added dynamic exercises and extra loads to the WBV. The mean total WBV exposure time varied around 20’ distributed in 1 or 2 series, with vibration times of 30” to 60” and the same rest time. The mean frequency of interventions was around 2 to 3 times a week, with a mean intervention time of 10 months. The main results include: decrease in body weight and improvement in the physiological variables of oxygen absorption, bone mineral density and arterial profile, indicating that WBV can be a safe tool in the fight against obesity and its implications. Level of Evidence II. Systematic Review of Level II Studies.

Mitochondrial DNA methylation and copy number predict body composition in a young female population

Background

Since both genomic and environmental factors are involved in obesity etiology, several studies about the influence of adiposity on both nuclear DNA and mitochondrial DNA methylation patterns have been carried out. Nevertheless, few evidences exploring the usage of buccal swab samples to study mitochondrial DNA epigenetics can be found in literature.

Methods

In this study, mitochondrial DNA from buccal swabs collected from a young Caucasian population (n = 69) have been used to examine potential correlation between mitochondrial DNA copy number and methylation with body composition (BMI, WHtR and bioimpedance measurements).

Results

A negative correlation between mitochondrial DNA copy number and BMI was measured in females (p = 0.028), but not in males. The mean percentage of D-loop methylation is significantly higher in overweight than in lean female subjects (p = 0.003), and a specific CpG located in the D-loop shows per se an association with impaired body composition (p = 0.004). Body composition impairment is predicted by a combined variable including mtDNA copy number and the D-loop methylation (AUC = 0.785; p = 0.009).

Conclusions

This study corroborates the hypothesis that mitochondrial DNA carries relevant information about body composition. However, wider investigations able to validate the usage of mtDNA methylation from buccal swabs as a biomarker are warranted.

Bioelectrical impedance phase angle in sport: a systematic review

BACKGROUND

Phase angle (PhA) is a raw BIA variable that has been gaining attention in recent years because it is supposed to be an index of the ratio between extracellular and intracellular water, body cell mass, and cellular integrity. The aim of this systematic review was to evaluate the variability of PhA between different sports and its relationships with sport performance. Additionally, we investigated whether PhA depends on gender or age, and analyzed the differences between athletes and controls.

METHODS

A systematic research using PubMed, Scopus and Web of Science up to June 2019 was performed. Selection criteria included studies on subjects who practice sports in planned and continuous modality at competitive or elite level.

RESULTS

Thirty-five papers met the inclusion criteria (twenty-one cross-sectional data, fourteen longitudinal data). A few but convincing studies have shown that mean PhA is higher in athletes vs. controls. PhA increases with age and is likely to be higher in male than female athletes. A large variability in PhA is observed for the same sport, while it is still uncertain to what extent PhA differs between various sports. There are no clear relationships of PhA with sport performance or training/untraining.

CONCLUSION

It is still to be defined to what extent PhA varies between different sports and changes with training/untraining. It can be argued that for a given sport much more data should be collected in a systematic way and for a period of time appropriate in order to determine changes and trends. This is even more crucial in the case of intervention studies.

Nutritional prognostic factors for survival in amyotrophic lateral sclerosis patients undergone percutaneous endoscopic gastrostomy placement

Objective: There are conflicting data on nutritional factors influencing survival in amyotrophic lateral sclerosis (ALS) patients after percutaneous endoscopic gastrostomy (PEG) placement. We performed an observational cross-sectional study evaluating body mass index (BMI) categories and cholesterol levels as prognostic factors for survival after PEG. Moreover, we assessed body composition in a subgroup of patients to better explain the influence of BMI on survival. Methods: Neurological and nutritional parameters were evaluated at the time of PEG implantation in 47 consecutive patients. Moreover, body composition was evaluated in a subgroup of 22 patients by bioelectrical impedance analysis. Survival was calculated as the time from the PEG placement to death. Results: Underweight patients had a significantly increased risk of death as compared to normal-weight patients using Cox regression analysis [HR = 3.37 (1.29-8.81); p = 0.04]. Similarly, older age at the onset of symptoms significantly increased the risk of death [HR = 1.07 (1.02-1.12); p = 0.001]. Neither overweight/obesity nor hypercholesterolemia affected survival. All ALS patients showed an altered body composition compared to the general population. In addition, a BMI <18.5 kg/m² identified patients with a significant reduction of body cell mass (BCM) and phase angle (PhA) compared to patients with normal BMI taken as the reference value. Conclusions: In the later stages of the disease, only a BMI < 18.5 kg/m² and older age at symptom onset had a prognostic value on survival. Dyslipidemia did not affect survival. The low BCM and PhA characterizing underweight patients support the role of BMI as a predictor of survival.