Association between phase angle from bioelectrical impedance analysis and level of physical activity: Systematic review and meta-analysis

Association between phase angle and body composition: New equations to predict fat mass and skeletal muscle mass

OBJECTIVE

The aim of this cross-sectional study was to develop new regression equations for estimating fat mass (FM) and skeletal muscle mass (SMM) in a heterogeneous Caucasian population, using the phase angle (PhA) as a bioelectrical parameter and DXA as the reference method. We also aimed to cross-validate the new equations, and to compare them with the manufacturers' equations.

METHODS

The 212 healthy Caucasian participants aged 20-65 years were randomly distributed into two groups: development group (n = 141) and validation group (n = 71). Bioelectrical parameters were obtained with a 50 kHz foot-to-hand phase-sensitive body composition analyzer. The new FM percentage (FM%) and SMM percentage (SMM%) equations were developed by performing multiple forward regression analyses. Agreement between DXA and the different equations was assessed by mean differences, coefficient of determination, standard error of the estimate (SEE), concordance correlation coefficient (CCC), and Bland-Altman plots.

RESULTS

The proposed equations explained 89.2% of the variance in the DXA-derived FM% and 91.8% in the DXA-derived SMM%, with low random errors (SEE = 3.04% and 1.92%, respectively), and a very strong agreement (CCC = 0.93 and 0.94, respectively). In addition, they demonstrated no fixed bias and a relatively low individual variability. However, the manufacturer's equations described a lower percentage of the variance, with higher random errors, obtained fixed bias of -5.77% for FM% and 4.91% for SMM%, as well as higher individual variability.

CONCLUSIONS

The new regression equations, which include the PhA as a bioelectrical parameter, can accurately predict DXA-derived FM% and SMM% in a heterogeneous Caucasian population, and are better options than the manufacturer's equations.

Association Between Phase Angle and Tongue Pressure in Older Inpatients with Connective Tissue Diseases

To investigate the association between tongue pressure (TP) and phase angle (PhA) in patients with connective tissue diseases (CTDs) aged 65 years or older. This retrospective cross-sectional study was conducted on 189 patients with CTDs who underwent hospital rehabilitation. TP was measured using a tongue pressure measuring device, and PhA was calculated from the bioimpedance analysis readings. Statistical analyses included multivariate linear regression with TP and receiver operating characteristic curves to determine PhA cutoff values indicative of low TP, defined as < 24.3 kPa for men and < 23.7 kPa for women. A total of 189 patients with CTDs (mean age 75 years; 49 men and 140 women; mean PhA 4.0°; mean TP 27.7 kPa) were included in the analysis. Fifty-five patients had low TP. Patients with low TP had lower PhA values than those with normal TP (mean PhA values 3.5° versus 4.3°). After adjusting for confounding factors, PhA (β = 0.387, p < 0.001) was significantly associated with TP. Cutoff values for PhA predicting low TP were identified as 3.9° for men and 3.5° for women. PhA is associated with TP, independent of other factors, in older inpatients with CTDs. The identified PhA cutoff values could enable the early detection of declining TP.

Six-month trajectory of phase angle after cardiovascular surgery and associated factors of the recovery during cardiac rehabilitation: A retrospective cohort study

BACKGROUND AND AIMS

Although the phase angle (PhA), a measure of frailty and sarcopenia, determined by bioelectrical impedance analysis has been reported as a prognostic factor after cardiovascular surgery, few studies have reported the trajectory of the PhA after discharge. In this study, we examined the trajectory of the PhA along with conventional physical function measures and explored the factors associated with recovery for 6 months after hospital discharge in patients who had undergone cardiovascular surgery.

METHODS

We included 116 patients who underwent elective cardiovascular surgery and cardiac rehabilitation after discharge. The PhA, physical function measures (grip strength, knee extension isometric muscle strength [KEIS], and usual gait speed), and Geriatric Nutritional Risk Index (GNRI) were assessed preoperatively, at discharge, and 3 and 6 months. Correlations between the PhA recovery rates and physical function and nutritional indices were assessed using Spearman's correlation analysis. Multivariate linear regression analysis was performed to examine the factors associated with recoveries of PhA and physical function indices (grip strength, KEIS, gait speed) after discharge.

RESULTS

Mean values of the PhA and physical function measurements and the GNRI score at discharge were lower than the preoperative values (PhA, -8.0 %; grip strength, -8.7 %; KEIS, -6.9 %; usual gait speed, -8.3 %; GNRI, -11 %). The grip strength, KEIS, and gait speed recovered to almost preoperative values 3 months after discharge. Values for the PhA and GNRI were still lower than preoperative values 3 months after discharge but had recovered to preoperative values at 6 months. The PhA was not significantly correlated with the recovery rates of the other indicators. Older age was negatively associated with PhA recovery rate, however, recovery rates decreased significantly with post-discharge physical activity.

CONCLUSIONS

In patients undergoing cardiovascular surgery, the PhA takes longer to recover than muscle strength or gait speed, requiring up to 6 months to recover to preoperative levels. Post-discharge interventions to increase daily physical activity may be an important method of speeding PhA recovery.

Pre-stroke patient characteristics that influence skeletal muscle quality: A cross-sectional study

AIM

One of the parameters that is measurable using bioelectrical impedance is the phase angle (PhA), which is an indicator of skeletal muscle quality. The PhA reflects cellular health and nutritional status and is an important parameter for monitoring recovery after stroke. However, the factors affecting skeletal muscle quality remain unclear. Therefore, this study aimed to identify the factors associated with skeletal muscle quality in patients with acute stroke.

METHODS

A total of 505 consecutively hospitalized patients with acute stroke were included in this study. The primary outcome was the PhA measured by bioelectrical impedance analysis, which evaluates muscle quality. Multiple regression analysis was performed to identify the factors affecting PhA.

RESULTS

The mean age of the participants was 75.1 years, and 44% were female. The median National Institutes of Health Stroke Scale (NIHSS) score upon admission was 4, and the mean length of stay was 18 days. The mean PhA for skeletal muscle quality was 4.9° in males and 3.9° in females. Multiple regression analysis showed that age, sex, pre-stroke modified Rankin Scale (pre-mRS), Geriatric Nutritional Risk Index, type 2 diabetes mellitus, atrial fibrillation, and chronic kidney disease had independent effects on PhA (R2 = 0.575; P = 0.001). Age, pre-mRS, NIHSS, dementia, and PhA independently associated with functional independence measure at discharge (R2 = 0.657; P = 0.001).

CONCLUSIONS

This study identified determinants contributing to the deterioration of muscle quality upon admission in acute stroke patients. Further investigation is needed to ascertain whether modulation of these factors improves muscle quality. Geriatr Gerontol Int 2025; 25: 213-219.

Associations of socio-demographic, anthropometric and behavioural factors with phase angle in older adults: a cross-sectional study in Taiwan

OBJECTIVE

Phase angle (PhA) is a prognostic factor for predicting and monitoring geriatric syndromes. However, multiple factors associated with increased PhA values as an outcome remain unclear in the older population. This study aimed to examine the association of socio-demographic, anthropometric and behavioural factors with PhA among older Taiwanese adults.

DESIGN

This cross-sectional study was conducted between May and August 2023.

SETTING

The study was carried out in northern Taiwan, specifically Taipei city and Yilan county.

PARTICIPANTS

Participants aged ≥65 years who were able to walk independently and had no artificial implants, such as cardiac pacemakers or joint replacements, were recruited using convenience sampling. A total of 198 participants were initially recruited for this study.

PRIMARY OUTCOME MEASURES

Data on socio-demographic and behavioural variables were collected using self-administered questionnaires. Anthropometric variables and PhA were measured using a multi-frequency bioelectrical impedance analyser (MC-780MA, TANITA). PhA was categorised into 'high' and 'low' using gender-specific cut-off points. A logistic regression analysis was performed.

RESULTS

A total of 152 participants (mean age: 72.0±5.5 years; 121 women (79.6%)) were included. Male (OR=0.72, 95% CI=0.02 to 0.33), unmarried (OR=0.22, 95% CI=0.06 to 0.82) and unemployed older adults (OR=0.16, 95% CI=0.03 to 0.87) were less probable to achieve high PhA values. After adjusting for potential confounders, older individuals with an increased body mass index (BMI) (OR=2.56, 95% CI=1.61 to 4.07) and greater muscle mass (OR=1.34, 95% CI=1.12 to 1.60) may have higher PhA values, whereas those with a greater fat mass may have lower PhA values (OR=0.61, 95% CI=0.48 to 0.78). No significant associations were observed between behavioural factors and PhA values.

CONCLUSIONS

The interventions designed to improve PhA should prioritise strategies tailored to male, unmarried or unemployed older adults, as well as those with low BMI, low muscle mass and high fat mass. Future studies with larger sample sizes are needed to confirm and strengthen our findings.

Correlation between Phase Angle and the Number of Medications in Older Inpatients: A Cross-Sectional Study

BACKGROUND

Muscle weakness in older adults elevates mortality risk and impairs quality of life, with the phase angle (PhA) indicating cellular health. Polypharmacy, common in geriatric care, could influence PhA. This investigates whether the number of medications and polypharmacy with PhA as a biomarker of muscle quality in older inpatients aged ≥65 and determines the extent to which multiple medications contribute to the risk of reduced muscle quality.

METHODS

This retrospective cross-sectional study analyzed data from older inpatients requiring rehabilitation. PhA was measured using bioelectrical impedance analysis. The number of medications taken by each patient was recorded at admission. Polypharmacy was defined as the concurrent use of five or more medications at admission.

RESULTS

In this study of 517 hospitalized older adults (median age 75 years; 47.4% men), 178 patients (34.4%) were diagnosed with sarcopenia. Polypharmacy was present in 66% of patients. The median PhA was 4.9° in men and 4.3° in women. Multivariate linear regression analysis was performed separately for men and women. In men, PhA was negatively correlated with the number of medications (β=-0.104, p=0.041) and polypharmacy (β=-0.045, p=0.383). In women, PhA was negatively correlated with the number of medications (β=-0.119, p=0.026) and polypharmacy (β=-0.098, p=0.063). Analyses were adjusted for age, body mass index, sarcopenia, C-reactive protein, and hemoglobin levels.

CONCLUSION

The number of medications at admission negatively impacted PhA in older inpatients, highlighting the importance of reviewing prescribed drugs and their interactions.

Improved trunk muscle quality in patients with stroke increases improvements in activities of daily living

BACKGROUND

This study aimed to determine whether an increased trunk muscle quality index (TMQI) is associated with activities of daily living (ADL) in patients ≥ 65 years of age with cerebral infarction in a convalescent rehabilitation ward.

METHODS

This retrospective observational study included patients aged ≥ 65 years who were admitted for post-stroke rehabilitation in Okinawa, Japan, between May 2018 and December 2022. The TMQI was calculated at admission and discharge using bioelectrical impedance analysis. Patients were divided into two groups based on the change in the TMQI during hospitalization: increase-in-TMQI and no-increase-in-TMQI groups. Multiple regression analysis was employed to explore the impact of increased TMQI on functional independence measure (FIM) -motor gain.

RESULTS

We included a total of 315 patients (79.1 ± 7.9 years of age, 51.7% men) in our analyses. Over half (165 [52.4%]) of the patients exhibited an increase in TMQI scores, and 150 (47.6%) patients did not exhibit an increase. No significant difference was observed in motor FIM score and motor FIM gain at admission and discharge between the groups with and without increased TMQI. Increased TMQI was independently associated with increased FIM-motor gain (adjusted R2 = 0.340 and R2 = 0.357, coefficient = 1.736, 95% confidence interval: 0.52-2.95, P = 0.005).

CONCLUSIONS

The results of this study suggest that increased TMQI has a positive effect on the recovery of physical function in patients with stroke. Further prospective studies are needed to elucidate the relationship between increased TMQI and ADL.

Use of phase angle as an indicator of overtraining in sport and physical training

The use of bioelectrical impedance analysis (BIA) is now well established in healthcare as an essential support tool for patient management in various clinical settings. Its use in sports is rapidly expanding due to the valuable insights it offers, helping to better structure athletes' diets and training programs, thereby optimizing their performance. In the context of sport, however, there is a consensus regarding the importance of proper interpretation of BIA-derived data, which cannot be limited to mere estimation of body composition. In this sense, therefore, the evaluation and interpretation of raw bioelectrical parameters, including resistance, reactance, and phase angle (PhA) is of relevant importance. The assessment of PhA is particularly significant in the context of sports, as it is closely linked to key factors such as muscle mass, strength, and overall muscle quality. However, the existing relationship between PhA and systemic, and loco-regional inflammation, which, in a broader sense, is the rationale behind its use for assessing and monitoring localised muscle damage. Thus, the importance of PhA monitoring during training becomes evident, as it plays a crucial role in assessing and potentially identifying functional impairments, such as overtraining syndrome, as well as muscle injury and related changes in fluid distribution, at an early stage. The aim of this review is to provide the scientific basis necessary to consider the use of whole-body PhA as an indicator of overtraining.

The Diagnostic Accuracy and Cutoff Value of Phase Angle for Screening Sarcopenia: A Systematic Review and Meta-Analysis

OBJECTIVES

Phase angle (PhA) declines with age and is a reliable marker for muscle function, making it a potential screening indicator for sarcopenia. However, studies examined the reliability and validity of PhA for detecting sarcopenia, yielding inconsistent results. This meta-analysis aimed to evaluate the accuracy and cutoff value of PhA for screening sarcopenia and examine the potential confounding factors.

DESIGN

This is a meta-analysis.

SETTING AND PARTICIPANTS

PubMed, Embase, and Cochrane Library were searched up to September 18, 2023. Eighteen studies (6184 participants) were included reporting the diagnostic accuracy of PhA for screening sarcopenia.

METHODS

Pooled accuracy [ie, the computed area under the curve value (AUC)] and cutoff value interval for screening sarcopenia were estimated using a random-effects model. Meta-regression analyses were conducted to identify sources of heterogeneity.

RESULTS

The AUC value was 0.81. Pooled sensitivity and specificity were 80% and 70%. The calculated 95% CI of the cutoff value of PhA for screening sarcopenia falls between 4.54° and 5.25°. The results of meta-regression analyses showed that ethnicity, body mass index (BMI), health status, and diagnostic criteria were the main factors affecting the diagnostic accuracy for screening sarcopenia (with all P values < 0.01).

CONCLUSION AND IMPLICATIONS

PhA may serve as a robust screening tool for sarcopenia, and the recommended cutoff interval falls between 4.54° and 5.25°. Ethnicity, BMI, health status, and diagnostic criteria can affect PhA's efficacy in sarcopenia screening.

Association between phase angle and sarcopenia in patients with connective tissue diseases

BACKGROUND AND AIMS

Early detection and management of sarcopenia in patients with connective tissue diseases (CTDs) are essential. However, the relationship between the phase angle and sarcopenia in patients with CTDs is unknown. This study investigated the association between the phase angle and sarcopenia in patients with (CTDs) and determined the optimal phase angle cutoff values for the early detection of sarcopenia.

METHODS

A retrospective cross-sectional study was conducted in 279 hospitalized patients with CTDs undergoing rehabilitation (median age 73.3 years; 80 men and 199 women). Bioimpedance analysis was used to measure the phase angle, and sarcopenia was assessed according to the Asian Working Group for Sarcopenia criteria.

RESULTS

Sarcopenia was identified in 134 patients (36 men and 98 women). Patients with sarcopenia had a significantly smaller phase angle than those without sarcopenia. Multivariate analysis revealed that phase angle was significantly associated with sarcopenia after adjusting for confounding factors in each sex. The optimal phase angle cutoff value for identifying sarcopenia was 4.6° for men and 4.3° for women, with area under the curve values of 0.795 and 0.754, respectively.

CONCLUSION

Phase angle is a valuable marker for identifying sarcopenia in patients with CTDs. The established phase angle cutoff values of 4.6° in men and 4.3° in women can facilitate the early detection and management of sarcopenia.

Longitudinal association of objectively measured physical activity and bioimpedance phase angle in older adults

BACKGROUND & AIMS

The benefits of physical activity, including exercise and daily and household chores, on the bioimpedance phase angle remain unclear. We aimed to examine the longitudinal association between objectively measured physical activity and bioimpedance phase angle among community-dwelling older adults.

METHODS

This community-based cohort study enrolled individuals aged 65 years or older without any disability in the basic activities of daily living. The exposure was physical activity level measured objectively using a tri-axial accelerometer at baseline. The outcome was a whole body phase angle at 50 kHz obtained from a bioelectrical impedance analyzer at a one-year follow-up. The linear regression model was fitted to estimate the continuous associations of physical activity level and phase angle with adjustment of confounders, including age, sex, body mass index, physical performance, and phase angle at baseline.

RESULTS

The primary analysis included 229 individuals (mean age = 72.6 years [standard deviation = 4.9], 62.9% females). In the multivariable linear regression model, physical activity level at baseline is associated with a greater phase angle at follow-up (mean difference per 1 increase, 0.53° [95%CI, 0.23-0.83]). Subgroup analysis by sex showed similar trends. Restricted cubic spline analysis indicated a linear association between phase angle at follow-up and physical activity level at baseline (p = 0.66 for non-linearity).

CONCLUSIONS

Higher physical activity level was associated with greater phase angle at one-year follow-up in a linear dose-response manner, independent of demographics, physical performance, and phase angle at baseline, in community-dwelling older adults.

Low phase angle is associated with swallowing outcomes in patients with acute stroke

BACKGROUND AND PURPOSE

Stroke-induced dysphagia is a critical complication that can lead to severe secondary worldwide health issues. This retrospective cohort study investigated the association between phase angle (PhA) and swallowing function in the acute phase of stroke. We aim to establish whether nutritional and muscular interventions associated with PhA could enhance swallowing recovery and reduce related risks post-stroke.

METHODS

Stroke patients requiring rehabilitation were assessed for the association between low PhA-with cutoff values for low PhA defined as less than 5.28 for men and 4.32 for women-and swallowing function using a functional oral intake scale (FOIS) on Day 7 after admission and after the completion of acute stroke treatment.

RESULTS

In this study of 140 acute stroke patients (median age 74[69-81], and 85 men and 55 women), 76 patients with low PhA significantly exhibited older age, lower body mass index, more decline in skeletal muscle mass index, and lower premorbid modified Rankin Scale scores compared to 64 patients with high PhA. Multivariate linear regression revealed that low PhA was independently associated with FOIS scores on Day 7 after admission (β=-0.143 and p=0.036) and after the completion of acute stroke treatment (β=-0.513 and p=0.024), even when adjusting for confounding factors.

CONCLUSIONS

Low PhA is associated with swallowing function in patients with acute stroke. Nutritional and physical interventions improving PhA may lead to a reduction of the risk associated with stroke sequelae.

Association of phase angle with sarcopenia in patients undergoing maintenance hemodialysis: A case-control study

Background

Sarcopenia, characterized by reduced muscle strength and mass, is commonly observed in patients with kidney disease. This study aimed to investigate the factors that influence sarcopenia in patients undergoing maintenance hemodialysis (HD patients).

Materials and Methods

A case-control study was conducted from 2022 to 2023, involving a total of 137 HD patients receiving regular dialysis. Relevant data were collected, and based on diagnostic criteria, patients were classified into sarcopenia and nonsarcopenia groups. All patients received polysulfone membrane HD at a flow rate of 500 mL/min. Bioelectrical impedance analysis was used to evaluate phase angle (PhA), muscle volume, and body composition.

Results

The prevalence of sarcopenia among maintenance HD patients was found to be 40.14%. There was a higher proportion of women (76.36%) with sarcopenia compared to men (P < 0.001). Furthermore, a significant difference was observed in PhA (P < 0.006) between patients undergoing maintenance HD with and without sarcopenia. PhA was positively associated with body mass index, body cell mass, basal metabolic rate, fat-free mass, soft lean mass, and minerals, whereas age and skeletal muscle index showed an inverse significant correlation.

Conclusion

Sarcopenia, a condition associated with increased mortality risk, affects a considerable proportion of dialysis patients. It is imperative to urgently identify and develop preventive and therapeutic strategies to counteract the detrimental effects of sarcopenia on the health outcomes of kidney patients.

Phase angle as an indicator of body composition and physical performance in handball players

BACKGROUND

Phase angle (PhA), obtained from the bioimpedance analysis, is widely used in clinical situations and in sports. This study evaluated the association between PhA with body composition and physical performance of handball athletes.

METHODS

43 national-level players (22.19 ± 3.86 years) of both sexes were evaluated regarding anthropometry, body composition, squat (SJ) and countermovement (CMJ) jumps, handgrip strength, and cardiorespiratory fitness.

RESULTS

We verified a correlation between PhA of the whole body and fat-free mass (r = 0.511), body mass index (r = 0.307), and body fat % (r = -0.303). There was a positive correlation between PhA of the whole body and SJ (r = 0.376), CMJ (r = 0.419), and handgrip for the dominant hand (r = 0.448). Moreover, PhA of the upper limbs was more strongly correlated with handgrip for the dominant (r = 0.630) and non-dominant hand (r = 0.575) compared to PhA of the whole body considering both sexes. Similarly, segmental PhA had a stronger significant correlation with SJ (r = 0.402) and handgrip for the dominant hand (r = 0.482) in males, as well as CMJ (r = 0.602) in females, compared to PhA of the whole body.

CONCLUSION

PhA of the whole body was positively related to fat-free mass, body mass index, body fat %, and lower- and upper-limbs strength in handball athletes. Segmental PhA might be used as a tool for estimating lower and upper limbs performance considering the sex, in preference to the PhA of the whole body.

Association between Physical Activity Level, Body Composition, and Phase Angle in University Students from Bioelectrical Impedance Analysis (BIA)

Background: The aim of this study is to determine the relationship between selected components of body composition and the phase angle specified by bioelectrical impedance analysis, depending on the level of physical activity among students. Materials and Methods: The study group consisted of 484 university students from Krosno. The diagnostic survey method (IPAQ-SF), measurements of highs, and analysis of body composition components (BIA) were used. The relationship between variables was determined using the χ2 test, the V-Kramer coefficient, and Spearman's rho coefficient. Results: University students in physical education demonstrated the highest level of physical activity and the lowest incidence of excessive body mass. Among the participants, 28.1% did not engage in any physical activity, or their level was insufficient. The PhA level was correlated with lean body mass and muscle mass. The correlation between higher levels of PA and PhA values was statistically significant, as was the relationship between self-assessment of physical fitness and the level of PA determined by IPAQ-SF. Conclusions: Preventive actions and educational programs, especially about spending leisure time in active ways, should be particularly targeted at students of disciplines with a significant amount of sedentary classes.

Glycated hemoglobin (HbA1c) is independently associated with the bioelectrical impedance phase angle in junior sumo wrestlers: A pilot study

The study explores the relationship between phase angle (PhA), an indicator of cellular health, and metabolic health parameters among junior sumo wrestlers in Japan. Given the demanding lifestyle and high-energy diets of sumo wrestlers that predispose them to metabolic syndrome post-retirement, this study focuses on a younger cohort. The primary aim is to evaluate if PhA could serve as an early indicator of metabolic health issues within this unique demographic. A total of 14 sumo wrestlers aged 9-17 years were assessed to determine the relationship between PhA and various metabolic markers, including glycated hemoglobin (HbA1c), using a TANITA MC-780A-N body composition analyzer and standard blood tests. Bivariate regression analysis and Pearson's correlation revealed a negative relationship between PhA and HbA1c even after adjusting for age and weight (ß = -0.496, r2 = 0.776, r = -0.756, p = 0.004). The results indicate a significant negative relationship between PhA and HbA1c levels, suggesting that lower PhA values, which indicate poorer cellular integrity, are associated with higher HbA1c levels, signifying impaired glycemic control. These findings underscore the potential of PhA as a valuable biomarker for monitoring metabolic health in young sumo wrestlers, with implications for early intervention and management strategies.

Association between the Thickness or Area of the Temporal Muscle and Skeletal Muscle Mass in Bioimpedance Analysis

INTRODUCTION

Sarcopenia associated with stroke can significantly impact patient prognosis; however, the current standard diagnostic methods for sarcopenia are rarely used in stroke patients. Therefore, the aim of the current study was to investigate whether the temporal muscle thickness (TMT) or area (TMA) could serve as a surrogate marker for measuring skeletal muscle mass.

METHODS

This retrospective chart review study was conducted on 244 participants from March 2018 to February 2020. The TMT and TMA were measured at the supraorbital roof level using brain CT or T1-weighted MR imaging obtained from participants. The skeletal muscle mass and skeletal muscle index (SMI) and whole-body phase angle (WBPA) at 50 kHz were collected. Pearson correlation analysis was used to assess the relationship between the TMT or TMA and the results of the bioimpedance analysis.

RESULTS

The mean TMT showed significant positive correlations with skeletal muscle mass (male, r = 0.520; female, r = 0.706), SMI (male, r = 0.426; female, r = 0.582), and WBPA (male, r = 0.295; female, r = 0.232). The mean TMA showed significant positive correlations with skeletal muscle mass (male, r = 0.490; female, r = 0.657), SMI (male, r = 0.289; female, r = 0.473), and WBPA (male, r = 0.232; female, r = 0.243).

CONCLUSION

We observed moderate to strong positive correlations between body composition analysis measured by BIA and TMT or TMA, suggesting that TMT or TMA could serve as a reliable surrogate marker for identifying low skeletal muscle mass in cerebrovascular disease.

Phase angle as an indicator of physical activity in patients with stable chronic obstructive pulmonary disease

OBJECTIVES

Phase angle (PhA) reflects cell membrane integrity and vitality and is an indicator of sarcopenia. PhA is associated with physical function in patients with stable chronic obstructive pulmonary disease (COPD). To our knowledge, the association between PhA and physical activity (PA) has not been investigated. Therefore, the aim of this study was to investigate whether PhA reflects PA in patients with COPD.

METHODS

This single-center, cross-sectional, observational study included 103 patients with stable COPD (87 men; mean age, 74.7 ± 8.1 y; mean forced expiratory volume in 1s %predicted value, 58.9 ± 20.4%). PhA was measured by bioelectrical impedance analysis. Patients were stratified into low (n = 54) and high (n = 49) PhA groups based on median values (4.3° ± 0.6° and 5.4° ± 0.5°, respectively). PA was calculated as the average daily duration of high-intensity light PA (HLPA; 2.0-2.9 metabolic equivalents [METs] of PA) and moderate- to vigorous-intensity PA (MVPA; >3 METs). Correlation and multivariate analyses using multiple regression analysis were performed to confirm the association between PhA and PA.

RESULTS

The high-PhA group demonstrated greater HLPA (104.4 [16.5-332.5] versus 131.3 [61.1-328.7] min, P = 0.005) and MVPA (19.5 [4.7-96.0] versus 46.6 [8.9-139.3] min, P < 0.001) than the low-PhA group. PhA was positively correlated with HLPA (r = 0.32, P < 0.001) and MVPA (r = 0.49, P < 0.001). MVPA (β = 0.178, P = 0.029) and HLPA (β = 0.158, P = 0.026) were associated with PhA independent of age, sex, body mass index, respiratory function, muscle strength, skeletal muscle mass index, and 6-min walking distance.

CONCLUSION

In patients with COPD, PhA may reflect PA as well as muscle function.

Relationship between the phase angle from bioelectrical impedance analysis and daily physical activity in patients with rheumatoid arthritis

OBJECTIVES

This study aimed to examine the relationship between daily physical activity and the phase angle (PhA) obtained by bioelectrical impedance analysis in rheumatoid arthritis (RA) patients.

METHODS

Data from a prospective cohort study of RA patients who were surveyed every year were analysed. The PhA was assessed by the bioelectrical impedance analysis method, and physical activity was assessed as the amount of time of exercise in metabolic equivalents (METs) per day using a triaxial accelerometer for 7 consecutive days. The association between physical activity and the PhA was evaluated using the isotemporal substitution model in multiple regression analysis.

RESULTS

Seventy-six RA patients were included in the analysis (81% female and age 66.2 ± 13.1 years). On cross-sectional analysis, the isotemporal substitution model in multiple regression analysis showed that the PhA was 0.05 points higher every 10 minutes when activities with intensity of 1 ≤ METs < 2 were replaced by activities with intensity of ≥3 METs (P = .01). Over 1 year, the rate of change in the PhA was 0.69% higher every 10 minutes when activities with intensity of 1 ≤ METs < 2 were replaced by activities with intensity of ≥3 METs (P = .037).

CONCLUSION

The PhA in RA patients may be related to physical activity level.

Relationship between Phase Angle and Physical Activity Intensity among Community-Dwelling Older Adults in Japan: A Cross-Sectional Study

This cross-sectional study aimed to determine the association between phase angle (PhA) and physical activity intensity in community-dwelling older Japanese adults. The intensity and time of physical activity for predicting high PhA were also examined. This study involved 67 community-dwelling older adults (mean age: 78.3 ± 5.5; female: 83.6%). We measured the physical activity and body composition of the participants. Physical activity was measured using a triaxial accelerometer, and light-intensity physical activity (LPA) and moderate-to-vigorous intensity physical activity (MVPA) hours per day were calculated from the results. Body composition was measured using Inbody S10, and the PhA was calculated from the measurements of the right side of the body. Bayesian statistical modeling revealed an association between PhA and MVPA (β = 0.256; p = 0.022; 95% Bayesian confidence interval [CI] = 0.001, 0.012), but not LPA (β = -0.113; p = 0.341; 95% Bayesian CI = -0.002, 0.001), even after adjustment for confounders. The cutoff value of MVPA predicting high PhA, calculated by the receiver operator characteristic curve, was 19.7 min/d (sensitivity = 0.906; specificity = 0.429). These results can be used to develop strategies to increase PhA in older adults and suggest that MVPA is important in this population.

Association of phase angle with sarcopenia and muscle function in patients with COPD: a case-control study

BACKGROUND AND AIMS

The predictive value of phase angle for sarcopenia diagnosis has been discussed for years. The present investigation was conducted to determine the association between phase angle and sarcopenia in patients with COPD.

METHODS

In this case-control study, 222 smoker men were divided into healthy and COPD groups. COPD was diagnosed by a pulmonologist through spirometry. Anthropometric indices, phase angle, muscle function, sarcopenia, and dietary intake were assessed.

RESULTS

A significant inverse association was observed between phase angle and sarcopenia after adjustment for age and energy intake (OR: 0.31, 95% CI 0.18-0.52) and after adjustment for BMI (OR: 0.31, 95% CI 0.18-0.52). A significant decrease was detected in anthropometric indices and indicators of sarcopenia and muscle function in COPD cases compared to the healthy controls.

CONCLUSIONS

Although further studies are suggested, phase angle might be considered an indicator of sarcopenia and muscle function in COPD patients.

Inflammatory and intestinal permeability biomarkers in healthy participants on long term vegan, vegetarian, omnivore and low-carbohydrate high-fat diet

Vegan, vegetarian and low-carbohydrate high fat (LCHF) diets can all offer several health benefits, if food choices are appropriate. In most studies examining their effects on systemic inflammation, participants were either overweight, on a weight loss programme or not matched for BMI, or had a pre-existing condition such as type 2 diabetes mellitus or hypertension. Little is known about the effects of dietary patterns on healthy and normal weight individuals. The aim of the present study was therefore to assess and directly compare inflammatory and intestinal permeability status in healthy participants following aforementioned or omnivore diet for at least 6 months. In this cross-sectional study, we measured the inflammatory biomarkers IL-6, TNF-α and CRP, and the markers of intestinal permeability LBP and zonulin, along with the analysis of lifestyle aspects, dietary intakes and physical activity, in 89 healthy participants. The groups were matched for sex, age and BMI. There were no differences in any of the measured parameters between the four groups and we found no strong correlations with dietary intakes. Using cluster analysis, participants were divided into eight clusters with more or less favourable inflammatory profiles; all clusters contained representatives of all patterns and all patterns were represented in each cluster. Significant differences between clusters were in the intake of mono-unsaturated fatty acids, ω-3/ω-6 ratio, phase angle and working two shifts. In healthy, normal-weight individuals, inflammatory status therefore does not depend on the dietary pattern itself, but is rather more complexly regulated and associated with dietary and non-dietary factors.

Phase angle is associated with sarcopenic obesity in post-stroke patients

BACKGROUND & AIMS

Evidence is limited concerning the association between bioimpedance analysis-derived phase angle and sarcopenic obesity. This study examined this association in patients who underwent convalescent rehabilitation after stroke.

METHODS

This cross-sectional study included hospitalized patients with post-acute stroke. The phase angle was measured using a multifrequency bioimpedance analysis. Sarcopenic obesity was diagnosed according to the European Society of Clinical Nutrition and Metabolism/European Association for the Study of Obesity criteria. A multiple linear regression analysis was used to examine the association between the phase angle and sarcopenic obesity after adjusting for confounding factors. A receiver operating characteristic curve was used to calculate the optimal phase angle cutoff value for predicting sarcopenic obesity.

RESULTS

A total of 760 patients (median age 71 years; 352 women) were analyzed. The median (interquartile range, 25th and 75th percentiles) phase angle was 4.45° (4.10°, 4.88°). Sarcopenic obesity was diagnosed in 16 (3.9%) men, 18 (5.1%) women, and 34 (4.5%) patients overall. The multiple linear regression analysis showed that sarcopenic obesity (β = -0.185, p = 0.017) and sarcopenia (β = -0.121, p = 0.012) were significantly and negatively associated with the phase angle. Obesity was not significantly associated with the phase angle (β = -0.078, p = 0.094). The optimal cutoff value of the phase angle for diagnosing sarcopenic obesity was 4.29° (sensitivity 0.65, specificity 0.80, area under the curve [AUC] 0.79, 95% CI 0.77-0.87, p < 0.001) in men and 3.84° (sensitivity 0.67, specificity 0.84, AUC 0.81, 95% CI 0.79-0.86, p < 0.001) in women.

CONCLUSION

The phase angle was associated with sarcopenic obesity, and the cutoff values of the phase angle that could predict sarcopenic obesity were 4.29° for men and 3.84° for women. This simple and practical phase angle-based prediction of sarcopenic obesity can be useful in clinical practice.

The Impact of Nutritional Markers and Dietary Habits on the Bioimpedance Phase Angle in Older Individuals

Low phase angle (PhA), as determined via bioelectrical impedance analysis, reflects unhealthy aging and mortality. In this study, we assessed whether nutritional status, including serum nutritional markers and dietary habits, is related to PhA in older individuals. We recruited 212 participants (aged ≥ 65 years) who underwent medical health checkups. PhA was measured using a multi-frequency impedance body composition analyzer. Habitual food and nutrient intake was evaluated using a brief, self-administered diet history questionnaire. Low PhA values were defined as ≤4.95 in males and ≤4.35 in females. Males with low PhA had poor exercise habits (p = 0.0429) and a lower body mass index (p = 0.0024). PhA was significantly correlated with serum cholinesterase levels, a nutritional status marker (r = 0.3313, p = 0.0004 in males; r = 0.3221, p = 0.0070 in females). The low-PhA group had significantly lower total energy and carbohydrate intake per ideal body weight (IBW) than the high-PhA group in males (total energy intake:30.2 ± 9.8 and 34.5 ± 9.3 kcal/kg/day, p = 0.0307; carbohydrate intake:15.2 ± 4.9 and 18.0 ± 5.8 kcal/kg/day, p = 0.0157). Total energy intake per IBW (adjusted odds ratio [95% confidence interval], 0.94 [0.89-1.00] per 1 kcal/kg/day increase) was independently associated with a low PhA in males. Our study revealed that lower total energy intake independently impacted low PhA in older males.

Association between Phase Angle and Body Composition of Children and Adolescents Diagnosed with HIV Infection

The aim of the study was to investigate how phase angle (PhA) is associated with subtotal and lumbar spine bone mineral density [BMD], lean soft tissue mass [LSTM], total body fat mass, android and gynoid in children and adolescents with HIV according to sex. A cross-sectional study was conducted in Florianópolis, Brazil, involving 64 children and adolescents vertically transmitted with HIV. Resistance and reactance values were obtained using bioelectrical impedance analysis, and PhA was subsequently calculated. Dual emission X-ray absorptiometry was used to assess body composition. Antiretroviral medication, physical activity (accelerometers) and skeletal maturation (wrist-carpal radiography) were used in the adjusted model. In males, PhA was directly associated with subtotal BMD (βadj: 0.65; R²: 0.38, p < 0.01) and lumbar spine BMD (βadj: 0.53; R²: 0.22, p = 0.01), directly associated with LSTM (βadj: 0.76; R²: 0.46, p < 0.01), and inversely associated with gynoid fat (βadj: -0.47; R²: 0.2, p = 0.01), in adjusted models. In females, PhA was directly associated with subtotal BMD (βadj: 0.46; R²: 0.17, p < 0.01) and lumbar spine BMD (βadj: 0.48; R²: 0.19, p < 0.01). It is concluded that PhA was directly associated with subtotal and regional BMD, LSTM, and inversely with gynoid fat in boys with HIV. In girls, PA was directly associated only with subtotal and regional BMD.

Association between Phase Angle and Subjective Perceptions of Health Variables in Cancer Patients

The phase angle, an increasingly studied healthcare tool, was studied to explore its relationship with psychological factors in cancer patients. The aim of this study was to investigate the relationship between the phase angle (PhA), obtained by the bioimpedance analysis of body composition, and psychological factors measured by questionnaire in cancer patients. The study included 311 patients who underwent bioimpedance testing to determine their PhA value; their psychological profiles were assessed using SF-36, FACIT, QLQ-C30, and GHQ-12 questionnaires. Mixed linear regression models were used to analyze the relationship between PhA and the psychological tests. The results showed a statistical correlation between PhA and the GHQ-12, FACIT, and SF-36 questionnaires, with higher PhA values associated with better results on the questionnaires. In the QLQ-C30 questionnaire, a correlation was observed between PhA and the functioning scales (p < 0.001), except for emotional and cognitive functioning (p = 0.148 and p = 0.544, respectively), but not in most of the symptom scales. The PhA is a useful tool for assessing the subjective health perception of cancer patients, especially with regard to psychological factors. While there is a statistically significant correlation, further research is required before confidently applying it in clinical practice. The current predictive value of this predictor for certain psychological aspects is limited, underscoring the need for additional research.

How Do Football Playing Positions Differ in Body Composition? A First Insight into White Italian Serie A and Serie B Players

The present study aimed to investigate how playing positions differ in specific body composition variables in professional soccer players with respect to specific field zones and tactical lines. Five hundred and six Serie A and B professional soccer players were included in the study and analyzed according to their playing positions: goalkeepers (GKs), central backs (CBs), fullbacks (FBs), central midfielders (MIDs), wide midfielders (WMs), attacking midfielders (AMs), second strikers (SSs), external strikers (ESs), and central forwards (CFs), as well as their field zones (central and external) and tactical lines (defensive, middle, and offensive). Anthropometrics (stature and body mass) of each player were recorded. Then, body composition was obtained by means of bioelectric impedance analysis (BIA). GKs and CFs were the tallest and heaviest players, with no differences from each other. Likewise, GKs and CFs, along with CBs, were apparently more muscular (for both upper and lower limbs) and fatter at the same time compared with the other roles. Overall, players of the defensive line (CBs and FBs), along with those playing in central field zones (CBs, MIDs, AMs, SSs, and CFs), were significantly (p < 0.05) superior in almost all anthropometric and body composition variables than those of middle and offensive line and external zones, respectively.

Association of 24-h movement behaviors with phase angle in community-dwelling older adults: a compositional data analysis

BACKGROUND

Phase angle (PhA) is an indicator of cellular conditions. Recent studies have suggested that PhA supports healthy aging. Identifying modifiable lifestyle factors for PhA is important. The associations of PhA in 24-h movement behaviors, including physical activity (PA), sedentary behavior (SB), and sleep, have not been studied in older adults.

OBJECTIVES

We investigated the cross-sectional associations between 24-h movement behaviors and PhA in community-dwelling older adults while appropriately considering the co-dependent nature of daily time use using compositional data analysis.

METHODS

The participants were 113 healthy older adults. PhA was measured using a bioelectrical impedance device. Time spent in light-intensity PA (LPA), moderate- to vigorous-intensity PA (MVPA), and SB was measured using a tri-axial accelerometer. Sleep duration information was self-reported in a questionnaire. Compositional multiple linear regression and compositional isotemporal substitution were performed to examine the associations of 24-h movement behaviors with PhA and hypothetical time reallocation in movement behaviors with PhA, respectively.

RESULTS

Even after adjusting for potential confounders, relative to other behaviors more time spent in MVPA was significantly associated with higher PhA (p < 0.001). The 30 min/day of time reallocation from the other behaviors (SB, LPA, and sleep) to MVPA was predicted to be 0.12 higher PhA (corresponding to 2.3% increase; 95% CI 0.01, 0.24).

CONCLUSIONS

Our results suggest that increasing or maintaining the daily time spent in MVPA is important for managing PhA in older adults, regardless of the other behaviors time consumed instead.

Effects of lipodystrophy and physical exercise on bioimpedance parameters in people living with HIV: A cross-sectional study

OBJECTIVE

The aim of this study was to evaluate the effects of lipodystrophy and physical exercise on the parameters of bioimpedance spectroscopy (BIS) and bioimpedance vector analysis (BIVA) of people living with HIV (PLWHIV).

METHODS

Seventy patients were divided into two groups: PLWHIV with lipodystrophy (PLWHIV-L) and PLWHIV without lipodystrophy (PLWHIV-NL). The phase angle (PhA) and the BIVA were determined from the values of resistance and reactance collected by the BIS. The percentage of fat mass and lean soft tissue (LST) were determined by dual-energy x-ray absorptiometry. For comparisons between the PLWHIV-L and PLWHIV-NL groups, the t test for independent samples or the Mann-Whitney test was used. From the BIVA, the average of the impedance vectors of the two groups was calculated with the 95% confidence ellipse, and the individual vectors of the patients divided by sex were also compared with the tolerance ellipses of 50%, 75%, and 95% of the healthy reference population. The relationships between the variables of interest were determined by the Pearson or Spearman correlation coefficient and the coefficient of determination. Analysis of covariance was used for comparisons between groups, adjusted for possible confounding variables.

RESULTS

PLWIV-L showed better hydration conditions (P <0.01), higher LST (P <0.01), and lower percent of fat mass (P <0.01). No differences in PhA were observed between PLWHIV who practiced or did not practice physical exercise. There was a significant difference between the impedance vectors of the groups with and without lipodystrophy (T = 42.4 and P <0.01). Additionally, most of the patients who were positioned beyond the ellipse limits of 50% of tolerance fell into the areas of edema and cachexia. The extracellular to intracellular water ratio explained 81% of the PhA variations. When PhA was adjusted for height², fat mass/height² and LST, it was significantly different between groups of the female sex (PhA: P <0.01).

CONCLUSION

Lipodystrophy and the practice of physical exercise do not present direct involvement in the PhA values, with sex, body composition, and hydration variables being the main influences on this variable. BIVA was able to show differences in the body composition of the groups even when the PhA values were similar.

Association of appendicular extracellular-to-intracellular water ratio with age, muscle strength, and physical activity in 8,018 community-dwelling middle-aged and older adults

BACKGROUND

The appendicular extracellular-to-intracellular water ratio (Ap ECW/ICW) has recently gained attention as a non-invasive measurable marker of muscle quality. However, there is a lack of basic evidence regarding age-related changes, sex differences, contribution to muscle strength independent of skeletal muscle mass (SMM), and potential improvement through physical activity (PA) in Ap ECW/ICW.

METHODS

This cross-sectional study enrolled 8,018 middle-aged and older Japanese individuals (aged 45-75 years). The Ap ECW/ICW and SMM were measured using segmental bioelectrical impedance spectroscopy. Muscle strength was evaluated by measuring the handgrip strength (HGS) with a dynamometer, and the PA level (PAL) was measured with an accelerometer. We performed a linear regression analysis of the associations of the Ap ECW/ICW with age, HGS, and PAL.

RESULTS

The Ap ECW/ICW increased by 0.019 for men and 0.014 for women per 5-year increase in age (p < 0.001), and the age-related increase was greater in men than in women (p for interaction <0.001). The Ap ECW/ICW was more strongly associated with the HGS than with the SMM in both men and women (p < 0.001). PAL showed a significant inverse association with the Ap ECW/ICW in both men and women (p < 0.001).

CONCLUSIONS

Ap ECW/ICW is higher with age, and it varies by sex. The Ap ECW/ICW may reflect muscle strength more than the SMM, suggesting that the Ap ECW/ICW may be improved by PA. The findings from this study may provide a framework for further Ap ECW/ICW research.

Bioelectrical impedance analysis in the BaSAlt cohort-study: the phase angle as an additional parameter for sarcopenia quantification among German nursing home residents?

PURPOSE

Sarcopenia is characterized by the loss of muscle mass, strength, and physical functioning. The bioelectrical impedance analysis (BIA) is a simplify method for the measurement of muscle quantity and quality. But there is a lack of evidence in the interpretation of the muscle quality parameter phase angle (PhA), which was recommended by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2). We hypothesize that the PhA shows differences between sarcopenia categorized groups and can be used as an additional parameter for sarcopenia quantification among residents of nursing homes (NH).

METHODS

Based on EWGSOP2 specifications, 78 residents from five German NH was categorized into sarcopenia groups. Group comparisons with Kruskal-Wallis tests, Dunn-Bonferroni post-hoc-Tests, and correlations with Spearman coefficients were conducted with the muscle quality parameter PhA.

RESULTS

Significant group differences by Kruskal-Wallis test for PhA was detected (H = 8.150, p = 0.017). The Dunn-Bonferroni post-hoc-Test showed significant results by group comparison for "confirmed/ severe sarcopenia" (4.1° [3.1-5.0]) with "no sarcopenia" (4.6° [3.7-11.2]; p =0 .049) and "probable sarcopenia" (4.7° [3.4-13.5]; p = 0.016), respectively.

CONCLUSIONS

There is a limitation for differentiation in preliminary stage of sarcopenia among multimorbid NH residents by PhA. Moreover, further research for specific cut-off-values and the individual sarcopenia progression monitoring by PhA are needed.

TRIAL REGISTRATION

No. AZ A2.5.4-096_aa (Date of approval: July 2019).

Association of phase angle with sarcopenia in chronic musculoskeletal pain patients: a retrospective study

BACKGROUND

In chronic musculoskeletal pain patients, detection of sarcopenia is of significant clinical interest. Phase angle, which can be measured through bioelectrical impedance analysis (BIA), can detect sarcopenia; however, the evidence in chronic musculoskeletal pain patients is limited. This study aimed to assess the relationship between phase angle and sarcopenia in patients with chronic musculoskeletal pain. Our hypothesis was that phase angle would be a useful indicator to identify sarcopenia in patients with chronic musculoskeletal pain.

METHODS

A total of 190 patients (51 men and 139 women) with chronic musculoskeletal pain were included in this retrospective cross-sectional study. Patient data of backgrounds, numeric rating scale score for pain, skeletal muscle index, and phase angle assessed using BIA were retrospectively reviewed. Sarcopenia was diagnosed using the Asian Working Group for Sarcopenia criteria 2019.

RESULTS

A total of 51 patients (26.7%), including 10 men (19.6%) and 41 women (29.5%), were diagnosed with sarcopenia. Phase angle, sarcopenia-related factors, age, and body mass index (BMI) differed significantly in patients with and without sarcopenia. On multiple logistic regression analysis, the prevalence of sarcopenia was significantly correlated with phase angle and BMI. The areas under the curve exhibited high accuracy in discriminating sarcopenia in men and moderate accuracy in both sexes and in women.

CONCLUSIONS

Phase angle may be a valid discriminator of sarcopenia in patients with chronic musculoskeletal pain.

Effects of muscle mass and muscle quality estimated by phase angle on functional outcomes in older patients undergoing rehabilitation: A prospective cohort study

BACKGROUND

Both skeletal muscle mass and muscle quality are important predictors of poor prognosis in older patients. However, the effects of muscle mass and muscle quality estimated by the phase angle (PhA) on functional outcomes in older patients undergoing rehabilitation have yet to be reported. This study aimed to investigate whether appendicular skeletal muscle index (SMI) and muscle quality estimated by PhA were independently associated with activities of daily living (ADL) and physical function in older patients undergoing rehabilitation.

METHODS

This prospective cohort study included older patients in a subacute rehabilitation hospital (n = 443). Baseline SMI and PhA were measured using bioelectrical impedance analysis, and low SMI or low PhA were determined using each cutoff value. The primary outcomes were ADL abilities measured using the functional independence measure for motor function (FIM-M) score and physical function measured using the short physical performance battery (SPPB) score at hospital discharge. Association between low SMI and low PhA and FIM-M or SPPB scores at discharge were determined using multiple regression analysis adjusted for confounding factors.

RESULTS

There were significant differences between the normal- and low-PhA groups in the FIM-M and SPPB scores at discharge (P < 0.001). In multiple regression analysis, low PhA was independently associated with FIM-M (β = -0.109, P = 0.013) and SPPB scores (β = 0.535, P < 0.001) at discharge; however, low SMI was not independently associated with these functional outcomes.

CONCLUSION

Decreased muscle quality estimated by the PhA was independently associated with poor ADL abilities and poor physical function in older patients undergoing rehabilitation.

Sex differences in the association of phase angle and lung cancer mortality

Background

Lung cancer is a lethal malignant tumor that is common worldwide and is associated with a high incidence of malnutrition. Phase angle (PA) is a simple, objective, and non-invasive indicator of body composition that has increasingly attracted attention as an indicator of the nutritional status and prognosis of patients with malignant tumors. This study aimed to investigate the association between the PA and overall survival in patients with lung cancer.

Methods

This study prospectively analyzed 804 lung cancer patients in the Investigation on Nutrition Status and its Clinical Outcome of Common Cancers (INSCOC) project from 40 hospitals in China. We used a restricted cubic spline to analyze the sex-specific association between PA and mortality in men and women with lung cancer. Cox regression analysis was used to evaluate the independent association between PA and mortality in men and women. Sensitivity analysis was performed. The Kaplan-Meier method was used to evaluate the survival of patients with high and low PA values.

Results

There was an L-shaped association between PA and survival in both men and women with lung cancer (p = 0.019 and p = 0.121, respectively). Kaplan-Meier survival analysis suggested that patients with a high PA showed a better survival than patients with a low PA (p = 0.007 for men and p < 0.001 for women). Multivariate-adjusted Cox regression analysis showed that PA was an independent risk factor for mortality in men (HR = 0.79, 95% CI = 0.65-0.95, p = 0.015), but not in women (HR = 0.83, 95% CI = 0.67-1.04, p = 0.105).

Conclusion

Phase angle is an independent risk factor for the mortality of male lung cancer patients. However, its role in predicting the mortality of female lung cancer patients seems to be limited.

Body Composition, Somatotype and Raw Bioelectrical Impedance Parameters of Adolescent Elite Tennis Players: Age and Sex Differences

Studies analyzing tennis players' body composition and morphological and bioelectrical characteristics are scarce, especially among adolescents. This study aimed to explore sex- and age-based differences in body composition, somatotype, and bioelectrical properties among elite young male and female tennis players aged 13-16 years. Twenty-two male (14.45 ± 1.10 years) and 20 female (14.30 ± 1.03 years) elite tennis players participated in this study and were compared according to sex (males vs. females) and, within each sex, according to age (13-14 years vs. 15-16 years). Female adolescent elite tennis players had higher body fat (BF) percentage and higher endomorphy than males. They also had lower skeletal muscle mass and total body water (TBW) percentages. Older boys had lower resistance and a higher TBW and phase angle (PhA) than younger boys, likely due to maturation and performance. No significant differences were found between younger and older girls, except for the PhA, potentially associated with better cell function and performance. This study provides valuable reference data for coaches of elite youth tennis players. Due to the few differences found in body composition and somatotype in the different age groups, the PhA may be used by practitioners as a reference for cell function and performance.

Phase angle (PhA) in overweight and obesity: evidence of applicability from diagnosis to weight changes in obesity treatment

Phase angle (PhA) is a recently proposed marker of nutritional status in many clinical conditions. Its use in patients with obesity presents different critical concerns due to the higher variability of the two measured parameters (resistance, R, and reactance, Xc) that contribute to the determination of PhA. Controversial is the relation between PhA and BMI that might vary with graded levels of obesity due to the variation in fat and free fat mass. Obesity is frequently associated with metabolic, hepatic, cardiovascular and kidney diseases that introduce variations in PhA values, in relation to multimorbidity and severity degree of these diseases. It is reported that the improvement of clinical condition is associated with a positive change in PhA. Also, the treatment of obesity with weight loss might confirm this effect, but with different responses in relation to the type and duration of the intervention applied. In fact, the effect appears not only related to the percentage of weight loss but also the possible loss of free fat mass and the nutritional, metabolic and structural modifications that might follow each therapeutic approach to decrease body weight. We can conclude that the PhA could be used as marker of health status in patients with obesity supporting an appropriate weight loss intervention to monitor efficacy and fat free mass preservation.

Phase angle and cellular health: inflammation and oxidative damage

Phase angle is a composite measure that combines two raw bioelectrical impedance analysis measures: resistance and reactance. Phase angle has been considered an indicator of cellular health, integrity, and hydration. As inflammation and oxidative stress can damage cellular structures, phase angle has potential utility in early detecting inflammatory and oxidative status. Herein, we aimed to critically review the current understanding on the determinants of phase angle and its relationship with markers of inflammation and oxidative stress. We also discussed the potential role of phase angle in detecting chronic inflammation and related adverse outcomes. Several factors have been identified as predictors of phase angle, including age, sex, extracellular to intracellular water ratio, and fat-free mass. In addition to these factors, body mass index (BMI) also seems to influence phase angle. Available data also show that lower phase angle values are correlated (negligible to high correlation coefficients) with higher c-reactive protein, tumour necrosis factor-α, interleukin-6, and interleukin-10 in studies involving the general and aging populations, as well as patients with chronic conditions. Although fewer studies have evaluated the relationship between phase angle and markers of oxidative stress, available data also suggest that phase angle has potential to be used as an indicator (for screening) of oxidative damage. Future studies including diverse populations and bioelectrical impedance devices are required to confirm the validity and accuracy of phase angle as a marker of inflammation and oxidative stress for clinical use.

Role of phase angle in older adults with focus on the geriatric syndromes sarcopenia and frailty

Age-related changes in body composition reflect an increased risk for disease as well as disability. Bioimpedance analysis is a safe and inexpensive bed side method to measure body composition, but the calculation of body compartments with BIA is hampered in older adults. Phase angle, a raw parameter derived from bioimpedance analysis, is free from calculation-inherent errors. It declines with age and disease and is highly predictive of a variety of clinical outcomes as well as mortality. This review summarizes the current evidence linking the phase angle to geriatric syndromes such as malnutrition, sarcopenia and frailty and also investigates whether the phase angle reacts to interventions. Since the majority of studies show an association between the phase angle and these geriatric syndromes, a low phase angle is not suitable to exclusively indicate a specific condition. It does not inform on the underlying cause and as such, a low phase angle mainly indicates increased risk. Phase angle decline over time is reflected by deterioration of e.g. frailty status. It reacts to physical training and detraining, but studies investigating whether these induced changes are also associated with improved outcome are missing.

Phase Angle as a Predictor for Physical Function in Institutionalized Independent Older Adults

The aim of this study was to investigate the relationship between phase angle (PhA) and physical function in institutionalized, independent older adults. Physical function was evaluated using the Senior Fitness Test Battery. PhA was measured by electrical bioimpedance at 50 khz, and body composition parameters were also registered. Results showed that PhA significantly correlated with all physical fitness tests, except for arm curls. Regarding the results of the multivariate analysis, three models were created: Model 1, formed by a dependent variable "PhA" and two predictor variables "8 ft up-and-go" and "6 min walk"; Model 2, formed by a dependent variable "PhA" and three predictor variables "8 ft up-and-go", "6 min walk" and "30-s chair stand"; and Model 3, formed by a dependent variable "PhA" and four predictor variables "8 ft up-and-go", "6 min walk", "30-s chair stand" and "arm curl". Results showed that predictor variables had a significant influence on the PhA for all three models (Model 1: p = 0.001, 12.5%; Model 2: p = 0.002, 12.9%; and Model 3: p = 0.005, 13.1%). For women, Model 1 showed a significant influence of predictor variables on the PhA (p = 0.030, 9.3%). The results for men in Models 1, 2 and 3 showed significant influences on the PhA (p = 0.002, 31.2%; p = 0.006, 31.6%; and p = 0.016, 31.6%; respectively). This study confirmed previous studies regarding to the relationship between PhA and physical function. It also indicates that PhA could be an excellent predictor of physical function.

Phase angle obtained via bioelectrical impedance analysis and objectively measured physical activity or exercise habits

The phase angle (PhA), measured via bioelectrical impedance analysis, is considered an indicator of cellular health, where higher values reflect higher cellularity, cell membrane integrity, and better cell function. This study aimed to examine the relationship between PhA and exercise habits or objectively measured physical activity. We included 115 people aged 32-69 years. The body composition and PhA were measured using a bioelectrical impedance device. Physical activity and sedentary behavior (SB) were assessed using a triaxial accelerometer. Exercise habits were also obtained through structured interviews, and participants were categorized into the no exercise habit (No-Ex), resistance training exercise habit (RT), or aerobic training exercise habit (AT) groups. Objectively measured moderate-to-vigorous physical activity or step count significantly correlated with PhA, independent of age, sex, height, percent body fat, body cell mass, and leg muscle power. In contrast, SB was not significant determinants of PhA. People who exercised regularly (RT or AT) had significantly higher PhA values than did those in the No-Ex group. Furthermore, the PhA was not significantly different between the RT and AT groups. Regularly engaging in exercise with moderate-to-vigorous intensity may improve or maintain muscle cellular health and muscle quality.

Association between phase angle and functional disability among patients with lumbar spinal stenosis: The SPSS-OK study

BACKGROUND

Whether the lower phase angle associated with worse physical function is a result of pain and muscle weakness in patients with lumbar spinal stenosis (LSS) is unclear.

OBJECTIVE

To evaluate the association between phase angle and back pain-specific disabilities in patients with LSS.

METHODS

In this single-center, cross-sectional study, 491 participants with LSS were enrolled. The phase angle and back pain-specific disability were measured using bioelectrical impedance analysis and the Oswestry Disability Index, respectively. General linear models were used to examine associations between phase angle and the Oswestry Disability Index with or without adjustment for age, sex, low back and lower limb pain, numbness in the lower extremities, total fat mass, and lower limb muscle mass.

RESULTS

The mean (SD) phase angle was 4.4∘ (1.0∘), and the mean Oswestry Disability Index was 36.1 (14.1) points. Greater phase angles were associated with less Oswestry Disability Index points (p= 0.037) independent of fat mass, low back pain, and hip or lower limb pain.

CONCLUSIONS

A lower phase angle was associated with worse functional disability. Low phase angle may be an indicator of functional impairment due to low back pain associated with LSS.

Combined resistance training with aerobic training improves physical performance in patients with coronary artery disease: A secondary analysis of a randomized controlled clinical trial

Background

The efficacy of combined resistance training (RT) and aerobic training (AT) compared with AT alone is well established in cardiac rehabilitation (CR); however, it remains to be elucidated whether RT load (high load [HL] vs. low load [LL]) modifies the outcomes. The aim of our study was to investigate the effects of HL-RT and LL-RT combined with AT in comparison to AT alone on body composition and physical performance in patients with coronary artery disease (CAD) enrolled in phase II CR.

Methods

We randomized 79 patients with a stable CAD to 12 weeks of lower limb LL-RT + AT (35-40% of one repetition maximum [1-RM]; n = 28), HL-RT + AT (70-80% of 1-RM; n = 26), or AT (n = 25). Fifty-nine patients (75% men) with mean (standard deviation) age 61 (8) years and left ventricular ejection fraction 53 (9)% completed LL-RT (n = 19), HL-RT (n = 21) and AT (n = 19). Body composition and physical performance (upper and lower submaximal muscle strength, flexibility, balance, and mobility) were measured at baseline and post-training.

Results

Training intervention had no significant impact on time × group interaction in the body composition measures. There was a significant time × group interaction for the gait speed test, chair sit-and-reach test, arm curl test, Stork balance test, up and go test, STS-5, and 6-min walk distance (p-values ≤ 0.001-0.04) following the training intervention. After the training intervention, HL-RT improved gait speed (+12%, p = 0.044), arm curl (+13%, p = 0.037), and time of Up and Go test (+9%, p < 0.001) to a greater extent compared with AT group, while there was a greater improvement in time of Up and Go test (+18%, p < 0.001) and time of five sit-to-stand tests (+14%, p = 0.016) following LL-RT when compared with AT. There were no differences between HL-RT and LL-RT in post-training improvement in any of the physical performance measures.

Conclusion

The combination of AT with HL-RT or LL-RT promoted similar improvements in physical performance, which were superior to AT. Therefore, both types of combined AT and RT can be applied to patients with CAD.

Clinical trial registration

[https://clinicaltrials.gov/ct2/show/NCT04638764] Identifier [NCT04638764].

Effect of resistance training on bioelectrical phase angle in older adults: a systematic review with Meta-analysis of randomized controlled trials

Resistance training has been proposed as a valid practice to counteract the aging effect on body mass and its components, which can be easily evaluated though the bioelectrical impedance analysis. This study aimed to achieve a systematic review with meta-analysis on the impact of resistance training on bioelectrical proprieties in older adults.A literature review was done in four electronic databases up to 1 January 2022. The inclusion criteria were: (i) participants aged ≥ 60 years; (ii) resistance training lasted ≥ 8 weeks; (iii) measurement of raw bioelectrical parameters in randomized controlled study designs.The outcomes of the trial had to be bioelectrical phase angle (PhA), resistance (R), and reactance (Xc). The methodological quality was assessed using the Rosendal scale.Overall, seven studies with a total of 344 participants were eligible for the analysis. The quality assessment yielded a score of 71.3%. Bioelectrical PhA (0.52 degree [95%CI 0.32, 0.71], p < 0.001) and Xc (3.58 ohms [95%CI 1.97, 5.19], p < 0.001) increased, whereas R decreased (-28.50 ohms [95%CI -41.39, -15.60], p < 0.001) after the resistance training programs.In this meta-analysis, resistance training promoted increases of PhA, which result from an increase in Xc concomitant with a reduction in R. According to the bioimpedance vector analysis, resistance-trained people experienced a beneficial leftward vector displacement, whilst inactivity induced a rightward vector displacement within the R-Xc graph. In future, more sophisticated and rigorous studies that address specific criteria, methods and targeted designs are required to identify which equipment and protocols allow for an optimization of the resistance training effects.Registration code in PROSPERO: CRD42020168057.

Age-, sex-, and maturity-associated variation in the phase angle after adjusting for size in adolescents

Background

Applied research using the phase angle (PhA) in children and adolescents has increased notably. Using multilevel modeling in a fully Bayesian framework, we examined the relationships between PhA, age, sex, biological maturity status, and body size in 10-16-year-old adolescents.

Methods

The sample comprised 519 adolescents (women, n = 241; men, n = 278) from Campinas, São Paulo, Brazil. Biological maturity status was assessed with self-examination of pubertal development for sexual maturity and maturity offset protocol to estimate age at peak height velocity (PHV) for somatic maturity status. Stature and body mass were measured by anthropometry. Phase angle was calculated based on raw resistance and reactance values (50 kHz frequency) obtained by bioelectrical impedance with the foot-to-hand technology.

Results

The multilevel regression analysis revealed that boys had significantly higher values of phase angle than girls, adjusting for age group and sexual maturity status. Overall, older and more mature adolescents had higher values of phase angle. When considering aligning variation in the phase angle by distance to estimated PHV (maturity offset), there was a higher association between the phase angle and time before and after predicted age at PHV for boys (r = 0.31, 90% CI: 0.23 to 0.39) than girls (r = 0.2, 90% CI: 0.11 to 0.28). When including body mass in the multilevel models, corresponding changes in the overall body mass mediate most of the influence of the maturity status and age group on the phase angle.

Conclusion

The present study demonstrated that the variability in phase angle is related to inter-individual variation in sex, age, and maturity status, as well as differences in body size. Research with adolescents considering phase angle should use multilevel modeling with standardized parameters as default to adjust for the concurrent influence of sex, age, maturity status, and body size.

Bioelectrical Impedance Analysis (BIA)- Derived Phase Angle in Children and Adolescents: A Systematic Review

Phase angle (PhA), a directly-measured bioelectrical impedance analysis variable, is suggested to be a proxy of body cell mass as well as extracellular/intracellular water ratio, and is related to cellular integrity and functions. The aim of this systematic review was to evaluate PhA in healthy youths in relation to sex, age, weight status, physical fitness, and sports activities. A systematic literature search (preferred reporting items for systematic reviews and meta-analyses criteria) until January 2022 was performed using PubMed, Embase, Scopus, and Web of Science regarding studies on PhA in healthy children and adolescents 4-18 years of age. Quality was assessed according to the National Institute of Health. After removing duplicates and studies not fulfilling the inclusion criteria, 22 cross-sectional and 1 longitudinal were considered appropriate. As for quality, 14 articles were rated fair and 9 good. Ten studies found that PhA increases with age: the increase was more marked after puberty, whereas changes in younger subjects are by far less defined. A clear sex difference was found in adolescents, likely due to pubertal development. Limited evidence suggests that PhA increases in participants with very high BMI. Limited data were reported on physically active youths without convincing findings. Positive associations of PhA with physical fitness and fat-free mass were found in few studies. In conclusion, partial and limited evidence suggests that changes in PhA over the first 2 decades of life reflect modification in body composition and fat-free mass composition. Further studies are needed for confirming PhA as a relevant marker of nutritional status in youths.

Brazilian Reference Percentiles for Bioimpedance Phase Angle of Healthy Individuals

Objectives

The present study was designed to estimate phase angle percentile curves for a broad age range of healthy individuals.

Methods

This is a cross-sectional study of healthy Brazilian individuals aged five to 80. InBodyS10 was used to assess phase angle. Reference curves were stratified by sex and estimated using Generalized additive models for location, scale, and shape as a continuous function of age. The phase angle determinants analyzed were physical activity, age, BMI, and SES variables.

Results

Data were analyzed from 2,146 individuals, 1,189 (55.2%) of whom were female. In both sexes, the phase angles showed a similar pattern (an increasing trend from childhood to the teenage phase, followed by stabilization during adult ages and a decrease in old adults). In female, the relationship between phase angle and age were associated with BMI and family income. In the male, the relationship between phase angle and age were associated with skin color and family income.

Conclusions

To the best of our knowledge, it is the first attempt to apply the GAMLSS technique to estimate phase angle percentiles in a healthy population covering most of the life cycle. We also showed that there are different phase angle determinants according to sex.

Montmorency tart cherry supplementation does not impact sleep, body composition, cellular health, or blood pressure in healthy adults

Background: Sleep disturbances are linked with cardiovascular and metabolic disease as well as poor body composition. Aim: To investigate the use of tart cherry supplements, which are high in antioxidants and may contain melatonin, on parameters of health such as sleep, body composition, cellular health, and blood pressure (BP). Methods: Forty-four participants had completed sleep record data and were included in this analysis. Participants consumed either two 240 ml bottles per day of Montmorency tart cherry (MTC) juice or placebo or two capsules per day of powdered MTC or placebo for 30 days. Participants tracked their sleep daily via questionnaire and completed body composition and BP assessments at baseline, 14 days, and 30 days after supplementation. Results: There were no significant differences in sleep time or quality between groups, though both increased over 30 days. The capsule groups had significantly lower body mass (BM) 14 days versus baseline for placebo group (p = 0.01, mean difference: 0.70 kg) and at 30 days versus 14 days in MTC group (p = 0.02, mean difference: 0.75 kg). No other differences in body composition or cellular health were found. BP was unaffected by MTC supplementation over 30 days. Despite the potential benefits of antioxidants and melatonin, we did not find improvements in sleep time or quality, cellular health or BP in participants consuming MTC for 30 days, though BM decreased in capsule groups. Conclusion: These results conflict with previous data on MTC and sleep and BP, therefore further investigation is warranted.

A Higher Phase Angle Is Associated with Greater Metabolic Equivalents in Women 1 Year After Bariatric Surgery

BACKGROUND

Phase angle (PhA), proposed as an indicator of the number, integrity, and function of cells and evaluated in some clinical situations, decreases after bariatric surgery (BS). In contrast, higher values are found in physically active or exercising individuals. We therefore evaluated the influence of physical activity on PhA after BS.

METHODS

The PhA and body composition (obtained by bioelectrical impedance analysis), physical activity level (obtained by International Physical Activity Questionnaire), and metabolic equivalents (METs) were evaluated in adult women submitted to BS. The PhA and body composition were evaluated at three time points: before and 6 and 12 months after surgery. Physical activity level and METs were measured at the two postoperative time points.

RESULTS

A reduction in PhA was observed 6 (p < 0.01) and 12 months (p < 0.01) after BS, with no significant difference between time points. A moderate or high physical activity level was found in 81% of the volunteers after 6 months and in 65% after 12 months. METs were reduced after 12 months compared to 6 months. A positive correlation (p < 0.05) was observed between PhA and body cell mass after surgery. There was a significant positive correlation (p < 0.01) between PhA and METs after 12 months.

CONCLUSIONS

Physical activity may attenuate the PhA reduction that occurs after BS, with this parameter reflecting the engagement of these patients in this type of activity.

Cardiovascular Diseases Diagnosis by Impedance Cardiography

Cardiovascular disease (CVD) represents the leading cause of mortality worldwide. In order to diagnose CVDs, there are a range of detection methods, among them, the impedance cardiography technique (ICG). It is a non-invasive and low-cost method. In this paper, we highlight recent advances and developments of the CDVs diagnosis mainly by the ICG method. We considered papers published during the last five years (from 2017 until 2022). Based on this study, we expressed the need for an ICG database for the different CDVs.