Validation of different bioimpedance analyzers for predicting cell mass against whole-body counting of potassium (40K) as a reference method

Bioimpedance Vector Analysis-Derived Body Composition Influences Strength and Power in Alpine Skiers

Purpose: Alpine ski racing is a complex sport where no single factor can exclusively account for performance. We assessed body composition, using bioelectrical impedance vector analysis (BIVA), and our purpose was to study its influence on the strength and power profile of young alpine skiers. Methods: Anthropometric measurements and advanced BIVA parameters were recorded on eighteen alpine ski racers (6 females/12 males; 17.0 ± 1.3 years; 172.2 ± 9.3 cm; 68.5 ± 9.8 kg). Dynamic force and power were assessed using countermovement jumps (CMJ), while maximal isometric strength was evaluated for hip flexion-extension and abduction-adduction movements. Stepwise regression models examined the relationship between BIVA-derived parameters and strength/power variables. Results: Body cellular mass (BCM) positively related to jump height (p = .021, R2 = 74%), jump momentum (p < .001, R2 = 89%), reactive strength index modified (p = .026, R2 = 75%) and peak concentric power (p < .001, R2 = 82%), while intracellular water (ICW) related to peak eccentric (p < .001, R2 = 76%) and concentric force (p < .001, R2 = 77%) as well as to concentric rate of force development together with the phase angle (PhA) (p = .008, R2 = 79% and R2 = 0.015). Regarding isometric assessment, ICW was a significant predictor for all four movement directions, and PhA contributed to hip adduction strength. Conclusions: Body composition, particularly BCM and ICW, significantly predict force- and power-related factors in young alpine skiers.

Comparison of series and parallel reactance to identify changes in intracellular water in response to physical training in athletes during a sports season

OBJECTIVE

Cross-sectional evidence has demonstrated that parallel reactance obtained by bioelectrical impedance analysis (BIA) may be an alternative to the regularly used series of measurements to predict intracellular water (ICW) in athletes. However, we are not aware of any studies that have determined the predictive role or compared the effectiveness of both series and parallel reactance for tracking ICW changes during an athletic season. The main aim of this study was to determine the predictive role and compare both series and parallel reactance (Xc) in tracking ICW during an athletic season.

RESEARCH METHODS AND PROCEDURES

This longitudinal study analyzed 108 athletes in the preparatory and competitive periods. Using dilution techniques, total body water (TBW) and extracellular water (ECW) were determined and ICW was calculated. Resistance (R), Xc, and impedance (Z) standardized for height were obtained through BIA spectroscopy using a frequency of 50kHz in a series array and then mathematically transformed in a parallel array.

RESULTS

Multiple regression analyses showed that only changes in parallel Xc and capacitance (CAP) (P < 0.05) were predictors of delta ICW during the sports season. In contracts, this was not the case for Xcs. Both changes in R and Z, series and parallel, predicted similarly the changes in ECW and TBW (P < 0.05) in athletes.

CONCLUSION

Our findings highlight the potential of parallel BIA values to detect changes in body water compartments over a competitive season. These data provide preliminary evidence that changes in parallel Xc/H, and ultimately CAP, represent valid markers of alterations in cell volume during a sports season.

The bioelectrical impedance analysis (BIA) international database: aims, scope, and call for data

BACKGROUND

Bioelectrical impedance analysis (BIA) is a technique widely used for estimating body composition and health-related parameters. The technology is relatively simple, quick, and non-invasive, and is currently used globally in diverse settings, including private clinicians' offices, sports and health clubs, and hospitals, and across a spectrum of age, body weight, and disease states. BIA parameters can be used to estimate body composition (fat, fat-free mass, total-body water and its compartments). Moreover, raw measurements including resistance, reactance, phase angle, and impedance vector length can also be used to track health-related markers, including hydration and malnutrition, and disease-prognostic, athletic and general health status. Body composition shows profound variability in association with age, sex, race and ethnicity, geographic ancestry, lifestyle, and health status. To advance understanding of this variability, we propose to develop a large and diverse multi-country dataset of BIA raw measures and derived body components. The aim of this paper is to describe the 'BIA International Database' project and encourage researchers to join the consortium.

METHODS

The Exercise and Health Laboratory of the Faculty of Human Kinetics, University of Lisbon has agreed to host the database using an online portal. At present, the database contains 277,922 measures from individuals ranging from 11 months to 102 years, along with additional data on these participants.

CONCLUSION

The BIA International Database represents a key resource for research on body composition.

Prediction of body water compartments by raw bioelectrical impedance parameters in athletes: Comparison between series and parallel measurements

BACKGROUND

The aim of this study was to determine the predictive role of series and parallel bioelectrical impedance-derived parameters in predicting total body (TBW), intracellular (ICW), and extracellular water (ECW) in athletes.

METHODS

This cross-sectional study analyzed 134 male (21.33 ± 5.11 years) and 64 female (20.45 ± 5.46 years) athletes. Using dilution techniques, TBW and ECW were determined while ICW was the difference between both. Raw and standardized for height (/H) bioelectrical resistance (R), reactance (Xc), and impedance (Z) values were obtained using a phase-sensitive device at a single frequency in a series array (s). These were mathematically transformed in a parallel array (p) and capacitance (CAP). Fat-free mass (FFM) was assessed by dual-energy X-ray absorptiometry.

RESULTS

Multiple regressions adjusted for age and FFM show that R/Hs, Z/Hs, R/Hp, and Z/Hp were significant predictors of TBW (p < 0.001 in females and males). While Xc/Hs did not predict ICW, Xc/Hp was a predictor (p < 0.001 in females and Males). In females, R/H and Z/H predicted similarly TBW, ICW, and ECW. In males, R/Hs was considered a better predictor than R/Hp for TBW and ICW, and the Xc/Hp was considered the best predictor for ICW. Another significant predictor of ICW was CAP (p < 0.001 in females and males).

CONCLUSION

This study highlights the potential value of parallel bioelectrical impedance values to identify fluid compartments in athletes as an alternative to the regularly used series measurements. Moreover, this study supports Xc in parallel, and ultimately CAP, as valid indicators of cell volume.

Future lines of research on phase angle: Strengths and limitations

Bioelectrical impedance analysis (BIA) is the most widely used technique in body composition analysis. When we focus the use of phase sensitive BIA on its raw parameters Resistance (R), Reactance (Xc) and Phase Angle (PhA), we eliminate the bias of using predictive equations based on reference models. In particular PhA, have demonstrated their prognostic utility in multiple aspects of health and disease. In recent years, as a strong association between prognostic and diagnostic factors has been observed, scientific interest in the utility of PhA has increased. In the different fields of knowledge in biomedical research, there are different ways of assessing the impact of a scientific-technical aspect such as PhA. Single frequency with phase detection bioimpedance analysis (SF-BIA) using a 50 kHz single frequency device and tetrapolar wrist-ankle electrode placement is the most widely used bioimpedance approach for characterization of whole-body composition. However, the incorporation of vector representation of raw bioelectrical parameters and direct mathematical calculations without the need for regression equations for the analysis of body compartments has been one of the most important aspects for the development of research in this area. These results provide new evidence for the validity of phase-sensitive bioelectrical measurements as biomarkers of fluid and nutritional status. To enable the development of clinical research that provides consistent results, it is essential to establish appropriate standardization of PhA measurement techniques. Standardization of test protocols will facilitate the diagnosis and assessment of the risk associated with reduced PhA and the evaluation of changes in response to therapeutic interventions. In this paper, we describe and overview the value of PhA in biomedical research, technical and instrumental aspects of PhA research, analysis of Areas of clinical research (cancer patients, digestive and liver diseases, critical and surgical patients, Respiratory, infectious, and COVID-19, obesity and metabolic diseases, Heart and kidney failure, Malnutrition and sarcopenia), characterisation of the different research outcomes, Morphofunctional assessment in disease-related malnutrition and other metabolic disorders: validation of PhA with reference clinical practice techniques, strengths and limitations. Based on the detailed study of the measurement technique, some of the key issues to be considered in future PhA research. On the other hand, it is important to assess the clinical conditions and the phenotype of the patients, as well as to establish a disease-specific clinical profile. The appropriate selection of the most critical outcomes is another fundamental aspect of research.

Influence of the type of electrodes in the assessment of body composition by bioelectrical impedance analysis in the supine position

BACKGROUND & AIMS

The main source of error in body composition assessment of bedridden patients by bioelectrical impedance analysis (BIA) is the electrode inadequacy and placement. As electrocardiogram (ECG) electrodes are often used for BIA measurements, this study aimed to compare three of them with a reference BIA electrode.

METHODS

BIA was performed sequentially on 24 healthy subjects in the supine position, using 3 different ECG electrodes (3M® Red Dot® 2330; Ambu® BlueSensor 2300; Ambu® BlueSensor SU-00-C) and the reference electrode (Bianostic AT®) for the BIA device (Nutriguard-M®, Data Input, Germany). Resistance (R), reactance (Xc), phase angle (PhA), appendicular skeletal muscle index (ASMI), fat-free mass index (FFMI) and fat mass percentage (FM%) obtained with the different electrodes were compared using Bland-Altman plots, repeated measures one-way ANOVA and paired t-test. Patient characteristics potentially involved in BIA measurement differences were assessed using linear regression analysis.

RESULTS

The study population consisted of 9 men and 15 women, 33% and 47% of whom were overweight, respectively. The measured R was within the physiological range for all men (428-561 Ω) and women (472-678 Ω), regardless of the type of electrodes used. Compared to the reference electrode, the 3M® Red Dot® 2330 and Ambu® BlueSensor SU-00-C electrodes gave significantly different Xc and PhA values, but only the Ambu® BlueSensor SU-00-C gave significantly different ASMI, FFMI and FM% at 50 kHz, with biases of -0.2 kg/m², -0.3 kg/m² and +1.4%, respectively. The higher the current frequency, the lower was the Xc and PhA measured by the Ambu® BlueSensor SU-00-C compared to the reference electrode. These measurement differences seemed mainly due to the too small gel area of the Ambu® BlueSensor SU-00-C (154 mm²) compared to the reference electrode (1311 mm²).

CONCLUSIONS

The use of electrodes with small gel area affects BIA measurement in the supine position, especially when PhA is used as an indicator of the nutritional status. Therefore, it is essential to specify the type of electrodes and carry out comparative tests before changing consumables for body composition assessment, to ensure BIA measurement reliability in clinical and research settings.

Overhydration Assessed Using Bioelectrical Impedance Vector Analysis Adversely Affects 90-Day Clinical Outcome among SARS-CoV2 Patients: A New Approach

Background: COVID-19 has taken on pandemic proportions with growing interest in prognostic factors. Overhydration is a risk factor for mortality in several medical conditions with its role in COVID-19, assessed with bioelectrical impedance (BI), gaining research interest. COVID-19 affects hydration status. The aim was to determine the hydration predictive role on 90 d survival COVID-19 and to compare BI assessments with traditional measures of hydration. Methods: We studied 127 consecutive COVID-19 patients. Hydration status was estimated using a 50 kHz phase-sensitive BI and estimated, compared with clinical scores and laboratory markers to predict mortality. Results: Non-surviving COVID-19 patients had significantly higher hydration 85.2% (76.9−89.3) vs. 73.7% (73.2−82.1) and extracellular water/total body water (ECW/TBW) 0.67 (0.59−0.75) vs. 0.54 (0.48−0.61) (p = 0.001, respectively), compared to surviving. Patients in the highest hydration tertile had increased mortality (p = 0.012), Intensive Care Unit (ICU) admission (p = 0.027), COVID-19 SEIMC score (p = 0.003), and inflammation biomarkers [CRP/prealbumin (p = 0.011)]. Multivariate analysis revealed that hydration status was associated with increased mortality. HR was 2.967 (95%CI, 1.459−6.032, p < 0.001) for hydration and 2.528 (95%CI, 1.664−3.843, p < 0.001) for ECW/TBW, which were significantly greater than traditional measures: CRP/prealbumin 3.057(95%CI, 0.906−10.308, p = 0.072) or BUN/creatinine 1.861 (95%CI, 1.375−2.520, p < 0.001). Hydration > 76.15% or ECW/TBW > 0.58 were the cut-off values predicting COVID-19 mortality with 81.3% and 93.8% sensitivity and 64 and 67.6% specificity, respectively. Hydration status offers a sensitive and specific prognostic test at admission, compared to established poor prognosis parameters. Conclusions and Relevance: Overhydration, indicated as high hydration (>76.15%) and ECW/TBW (>0.58), were significant predictors of COVID-19 mortality. These findings suggest that hydration evaluation with 50 kHz phase-sensitive BI measurements should be routinely included in the clinical assessment of COVID-19 patients at hospital admission, to identify increased mortality risk patients and assist medical care.

Modulatory Effects of Physical Activity Levels on Immune Responses and General Clinical Functions in Adult Patients with Mild to Moderate SARS-CoV-2 Infections-A Protocol for an Observational Prospective Follow-Up Investigation: Fit-COVID-19 Study

Background: This proposal aims to explain some of the gaps in scientific knowledge on the natural history of coronavirus disease (COVID-19), with a specific focus on immune, inflammatory, and metabolic markers, in parallel with temporal assessment of clinical and mental health in patients with COVID-19. The study will explore the temporal modulatory effects of physical activity and body composition on individual trajectories. This approach will provide a better understanding of the survival mechanisms provided by the immunomodulatory role of physical fitness. Methods: We will conduct a prospective observational cohort study including adult patients previously infected with the SARS-CoV-2 virus who have expressed a mild to moderate COVID-19 infection. Procedures will be conducted for all participants at baseline, six weeks after vaccination, and again at 12 months. At each visit, a venous blood sample will be collected for immune phenotypic characterization and biochemistry assays (inflammatory and metabolic parameters). Also, body composition, physical activity level, cardiovascular and pulmonary function, peripheral and respiratory muscle strength, functional exercise capacity, and mental health will be evaluated. Using the baseline information, participants will be grouped based on physical activity levels (sedentary versus active), body composition (normal weight versus overweight or obese), and SARS-CoV-2 status (positive versus negative). A sub-study will provide mechanistic evidence using an in-vitro assay based on well-trained individuals and age-matched sedentary controls who are negative for SARS-CoV-2 infection. Whole blood will be stimulated using recombinant human coronavirus to determine the cytokine profile. Peripheral blood mononuclear cells (PBMCs) from healthy well-trained participants will be collected and treated with homologous serum (from the main study; samples collected before and after the vaccine) and recombinant coronavirus (inactive virus). The metabolism of PBMCs will be analyzed using Respirometry (Seahorse). Data will be analyzed using multilevel repeated-measures ANOVA. Conclusions: The data generated will help us answer three main questions: (1) Does the innate immune system of physically active individuals respond better to viral infections compared with that of sedentary people? (2) which functional and metabolic mechanisms explain the differences in responses in participants with different physical fitness levels? and (3) do these mechanisms have long-term positive modulatory effects on mental and cardiovascular health? Trial registration number: Brazilian Registry of Clinical Trials: RBR-5dqvkv3. Registered on 21 September 2021.

Muscle weakness as an additional criterion for grading sarcopenia-related prognosis in patients with cancer

Background

Low muscle strength has been pointed out as a key characteristic of sarcopenia, but the prognostic significance of muscle function next to reduced skeletal muscle mass (SMM) in patients with cancer has been scantily investigated.

Methods

Data on muscle strength by handgrip (HG) dynamometry and total‐body SMM estimated by bioelectrical impedance analysis (BIA) of Italian and German patients with cancer observed prospectively until death or censoring were analysed (N = 1076). Patients were stratified in four risk categories based on low HG (<10th percentiles of age and gender‐specific normative values) and low total‐body SMM according to SMM index cutoffs (<10.75 and <6.75 kg/m² in men and women, respectively).

Results

During a median follow‐up of 58 months [25th–75th percentile, 37–60], 566 patients had died. Patients presenting low HG in combination or not with low SMM were characterised by shorter median survival (12.7 vs. 27.2 months, respectively; p < 0.001) compared to those with low SMM/normal HG and normal SMM/normal HG (>60 months for both). After adjusting for sex, age, body mass index and percentage of weight loss, disease's stage, performance status and type of cancer, compared to reference category (normal HG and SMM; N = 210) the hazard ratios were: low SMM/normal HG (N = 342), 0.83 [95% confidence interval, CI, 0.67–1.02] (p = 0.073); normal SMM/low HG (N = 158), 1.19 [95% CI, 1.07–1.32] (p = 0.002); low SMM/low HG (N = 366), 1.39 [95% CI, 1.27–1.53] (p < 0.001).

Conclusions

Muscle weakness was found to be a more powerful predictor of survival than BIA‐estimated SMM and should be considered as an additional key feature of sarcopenia in patients with cancer.

Low muscle strength has been pointed out as a key characteristic of sarcopenia, but the prognostic significance of muscle function next to reduced skeletal muscle mass (SMM) in patients with cancer has been scantily investigated. Muscle weakness was found to be a more powerful predictor of survival than SMM and should be considered as additional key feature of sarcopenia in patients with cancer.

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

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

Precision and accuracy of bioelectrical impedance analysis devices in supine versus standing position with or without retractable handle in Caucasian subjects

BACKGROUND & AIMS

Bioelectrical impedance analysis (BIA) could be facilitated in subjects who are able to stand by using scales without (BIA_std4) or with a retractable handle (BIA_std8), provided that they are as precise as BIA devices commonly used in the supine position in the hospital setting (BIA_sup). This observational prospective cross-sectional study aimed to compare the precision and accuracy of BIA_std4, BIA_std8 and BIA_sup in a Caucasian population.

METHODS

Fat mass percentage (FM%) was measured in 160 healthy Caucasian subjects (80 men/80 women) aged 20-60 years, with a body mass index (BMI) ≥18.5 and < 30 kg/m², using the HAGRID Body Fat Scales (Huawei Technologies Co., Ltd., China) in BIA_std4 or BIA_std8 mode, and the Nutriguard-M (Data Input GmbH, Germany) as BIA_sup. Intra-unit and inter-unit precisions of each device were evaluated by calculating the coefficients of variation (CV%) of 3 measurements with 3 different units of each device. Inter-device precisions were evaluated with Pearson correlations, Bland-Altman plots, and repeated measures ANOVA followed by post-hoc Bonferroni tests. Accuracy of these BIA devices was estimated in a subgroup of 16 subjects, using comparison with dual-energy X-ray absorptiometry (DXA).

RESULTS

The study population was 40 ± 12 years old, with a body height and weight of 171 ± 10 cm and 72.2 ± 11.5 Kg, respectively. All three devices were very precise with intra-unit CV% of 0.5%, 0.9%, and 0.3% and inter-unit CV% of 0.5%, 1.1%, and 0.4% for BIA_std4, BIA_std8 and BIA_sup, respectively. Inter-device precision was ±2.1% for BIA_std4/BIA_sup, ±1.9% for BIA_std8/BIA_sup, and ±1.3% for BIA_std8/BIA_std4. Bland-Altman plots showed bias ±1.96 SD of 0.3 ± 5.2% for BIA_std4/BIA_sup, -0.4 ± 4.5% for BIA_std8/BIA_sup and -0.6 ± 3.1% for BIA_std8/BIA_std4. Compared to DXA, all three devices tended to underestimate FM% in men with low BMI, while only BIA_std4 and BIA_std8 tended to overestimate FM% in women with high BMI. FM% measurement accuracy was ±2.6% for BIA_sup/DXA, ±3.3% for BIA_std4/DXA, and ±3.4% for BIA_std8/DXA.

CONCLUSIONS

Both BIA_std4 and BIA_std8 show a good intra- and inter-unit precision close to BIA_sup, making them suitable for rapid body composition assessment in non-bedridden subjects. However, all these three devices should not be used interchangeably, because BIA_std4 and BIA_std8 tend to accentuate FM% changes during body composition monitoring compared to BIA_sup and DXA.

TRIAL REGISTRATION

ClinicalTrial.gov no. NCT04504799.

Cortisol concentration affects fat and muscle mass among Polish children aged 6-13 years

Background

Cortisol is a steroid hormone acting as a stress hormone, which is crucial in regulating homeostasis. Previous studies have linked cortisol concentration to body mass and body composition.

Methods

The investigations were carried out in 2016–2017. A total of 176 children aged 6–13 years in primary schools in central Poland were investigated. Three types of measurements were performed: anthropometric (body weight and height, waist and hip circumferences), body composition (fat mass FM (%), muscle mass – MM (%), body cellular mass - BCM (%), total body water - TBW (%)), and cortisol concentration using saliva of the investigated individuals. Information about standard of living, type of feeding after birth, parental education and maternal trauma during pregnancy was obtained with questionnaires.

Results

The results of regression models after removing the environmental factors (parental education, standard of living, type of feeding after birth, and maternal trauma during pregnancy) indicate a statistically significant association between the cortisol concentration and fat mass and muscle mass. The cortisol concentration was negatively associated with FM (%) (Beta=-0.171; p = 0.026), explaining 2.32 % of the fat mass variability and positively associated with MM (%) (Beta = 0.192; p = 0.012) explaining 3.09 % of the muscle mass variability.

Conclusions

Cortisol concentration affects fat and muscle mass among Polish children.

Trial registration

The Ethical Commission at the University of Lodz (nr 19/KBBN-UŁ/II/2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02837-3.

The prognostic impact of BIA-derived fat-free mass index in patients with cancer

BACKGROUND & AIMS

Reduced muscle mass represents one of the top ranked phenotypic criteria for malnutrition proposed by the Global Leadership Initiative on Malnutrition. Although height-indexed fat-free mass (FFMI) thresholds have been proposed as useful surrogate measures of reduced muscle mass, the independent prognostic value of BIA-derived FFMI by bioelectric impedance analysis (BIA) in patients with cancer still needs to be fully explored.

METHODS

Data on body mass index (BMI), 6-month percentage of weight loss (%WL), FFMI by BIA and quality of life (QoL by EORTC Quality of Life Questionnaire [EORTC QLQ-C30]) of Italian and German patients observed prospectively until death or censoring were used (N = 1217). Patients were stratified in 5 risk categories according to a robustly validated scoring system based on BMI and %WL. Low FFMI was defined as follows: men, <17 kg/m²; women, <15 kg/m².

RESULTS

Reduced FFMI was found in 234 patients (19.2%). After a median follow-up of 57 months [25th-75th, 31-60], 620 patients (50.9%) had died. The study detected differences in survival between patients presenting with and without reduced FFMI (14.0 months vs. 45.1 months; P < 0.001). The fully-adjusted hazard ratio of mortality for low FFMI was 1.46 [95%CI, 1.18-1.81] (P < 0.001). Low FFMI was also independently associated with reduced QoL: fully-adjusted odds ratio, 1.50 [95%CI, 1.00-2.25] (P = 0.050).

CONCLUSIONS

Reduced FFMI by BIA independently predicted survival and was associated with impaired QoL. Altered body composition should always be considered in all patients with cancer as additional phenotypic criterion of poor prognosis and BIA offers the possibility of multiple, noninvasive bedside assessments.

Impact of Vigorous-Intensity Physical Activity on Body Composition Parameters, Lipid Profile Markers, and Irisin Levels in Adolescents: A Cross-Sectional Study

In adolescence, health status is influenced by several factors, including dietary pattern and physical activity (PA) which are crucial elements of lifestyle in terms of prevention and treatment of metabolic and chronic diseases. The current study aimed to explore the impact of the different intensity levels of PA along with the adherence to a Mediterranean diet (MD), on body composition indices and metabolic parameters in a cohort of adolescents, thereby investigating potential predictors of health behavior in youth. This cross-sectional study was carried out among 92 participants (44 girls and 48 boys, aged 14 to 17 years), which were divided into the following three groups according to intensity levels of PA: Group A (physical inactivity), Group B (moderate PA), and Group C (vigorous-intensity PA). The Questionnaire of Adherence to the Mediterranean Diet (KIDMED test) was used to assess both diet composition and adherence to a MD. All subjects underwent anthropometric measurements, bio-impedentiometric analysis for body composition parameters, and biochemical and hormonal measurements. The majority of adolescents (60.87%) had a medium adherence to the MD, and even a better distribution of food rates was found in adolescents performing vigorous-intensity PA. A comparison of anthropometric measurements and body composition parameters among groups showed that body mass index and fat mass (FM) were significantly lower while body cell mass (BCM), free fat mass (FFM), phase angle (PhA), and total body water (TBW) were higher in Group C adolescents as compared with those of Group A. In Group C, insulin resistance (HOMA-IR) was reduced and insulin levels were inversely associated with FFM (r = −0.454 and p = 0.004) and directly correlated with FM (r = 0.331 and p = 0.003). In the same Group C, we observed elevated serum irisin levels and lower lipid profile markers as compared with Group A. Interestingly, irisin negatively correlated with both total cholesterol (r = −0.428 and p = 0.04) and LDL (r = −0.468 and p = 0.02) in Group C. Finally, a receiver operator characteristic curve (ROC) analysis revealed irisin, LDL, HDL, and body composition variables (FFM, BMC, PhA, and TBW) as the most predictive measures for vigorous-intensity PA. Our results highlight the importance of developing healthy lifestyle programs that include improving the intensity of PA among a young population as a superior strategy for ensuring a better quality of life.

Body Composition and Leptin/Ghrelin Levels during Lenvatinib for Thyroid Cancer

Weight loss is one of the most frequent adverse events during treatment with multikinase inhibitors, but scanty data are available on its extent and characteristics. This is the first assessment of the body composition by bioelectrical impedance analysis and of circulating leptin and ghrelin levels, in patients with advanced thyroid cancer before and at regular intervals during treatment with the tyrosine kinase inhibitor lenvatinib. Body mass index (BMI) decreased in all patients, with an average ∆ reduction of -6.4, -9.8, and -15.3% at 3, 6, and 12 months of treatment, respectively. Interestingly, in most patients, after the first year of treatment, BMI remained stable. In all patients, fat mass (FM) reduced more than fat-free mass, the highest decrement being of -60 and -16%, respectively. A decrease in the body cell mass, a parameter mainly due to muscle tissue, was observed only in patients with a vast baseline muscular mass. Total body water decreased in parallel to BMI. During treatment, leptin tightly paralleled the decrease of BMI values, consistent with the decrease in FM, whereas ghrelin levels increased upon BMI decrease. The loss of the FM accounts for the largest portion of BMI reduction during lenvatinib treatment. The increase in ghrelin could account for the BMI stabilization observed after 1 year of treatment. Nevertheless, oral nutritional supplements should be given as early as possible and athletic patients should be encouraged to maintain physical activity. In some circumstances, parenteral nutrition is required for the rehabilitation of these patients.

Longitudinal changes and correlations of bioimpedance and anthropometric measurements in pregnancy: Simple possible bed-side tools to assess pregnancy evolution

PURPOSE

The aim of this study was to assess longitudinal changes of bioimpedance analysis compared with anthropometric measurements in low-risk pregnant woman recruited in the first trimester and to observe possible differences in these indices in women who developed high-risk pregnancies.

MATERIALS AND METHODS

Bioimpedance indices for the three trimesters of pregnancies were calculated separately for uneventful pregnancies delivered of newborns > the 10th centile. These findings were compared with anthropometric measurements. Data of women who developed hypertensive disorders of pregnancy (HDP) or delivered SGA newborns were calculated and compared.

RESULTS

Significantly longitudinal increases were observed in these pregnancies for total body water (TBW), free fat mass, fat mass, and extra-cellular water. These increases were paralleled body mass index (BMI), skinfolds, and waist measurements. The correlations between these two sets of findings were poor. Women who developed HDP with AGA fetuses showed significantly different bioimpedance from normal cases. TBW indices were highly significantly different since the first trimester. In pregnancies delivered of SGA newborns, these indices were opposite of the values observed in patients with HDP-AGA, TBW in these patients was significantly reduced compared with normal pregnancies.

CONCLUSIONS

The bioelectrical impedance is a fast, simple, noninvasive way to assess the TBW content in pregnancy. Our findings are in agreement with the hypothesis that bioimpedance might help to identify early in gestation patients at risk of developing different clinical phenotypes of hypertensive disease of pregnancy and SGA fetuses.

Postoperative fluid retention after heart surgery is accompanied by a strongly positive sodium balance and a negative potassium balance

The conventional model on the distribution of electrolyte infusions states that water will distribute proportionally over both the intracellular (ICV) and extracellular (ECV) volumes, while potassium homes to the ICV and sodium to the ECV. Therefore, total body potassium is the most accurate measure of ICV and thus potassium balances can be used to quantify changes in ICV. In cardiothoracic patients admitted to the ICU we performed complementary balance studies to measure changes in ICV and ECV. In 39 patients, fluid, sodium, potassium, and electrolyte‐free water (EFW) balances were determined to detect changes in ICV and ECV. Cumulatively over 4 days, these patients received a mean ± SE infusion of 14.0 ± 0.6 L containing 1465 ± 79 mmol sodium, 196 ± 11 mmol potassium and 2.1 ± 0.1 L EFW. This resulted in strongly positive fluid (4.0 ± 0.6 L) and sodium (814 ± 75 mmol) balances but in negative potassium (−101 ± 14 mmol) and EFW (−1.1 ± 0.2 L) balances. We subsequently compared potassium balances (528 patients) and fluid balances (117 patients) between patients who were assigned to either a 4.0 or 4.5 mmol/L blood potassium target. Although fluid balances were similar in both groups, the additionally administered potassium (76 ± 23 mmol) in the higher target group was fully excreted by the kidneys (70 ± 23 mmol). These findings indicate that even in the context of rapid and profound volume expansion neither water nor potassium moves into the ICV.

Pre- and postoperative nutritional deficiencies in obese patients undergoing laparoscopic sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) has been identified as an innovative surgical approach for the treatment of obesity and is increasingly applied worldwide. However, data on outcome of LSG regarding nutrient deficiencies, protein status, and body composition are scarce.

METHODS

Obese subjects (54; f:m = 4:1) scheduled for LSG were included in this study. Micronutrient analysis, protein status assessment, and bioimpedance measures were performed before and 1, 3, 6, and 12 months after LSG.

RESULTS

In 51% of the subjects, at least one micronutrient deficiency was found prior to surgery. Baseline concentrations were below normal for 25-OH vitamin D (27%), iron (29%), vitamin B6 (11%), vitamin B12 (9%), folate (6%), and potassium (7%). Frequencies of deficiencies for vitamin B12, folate, iron, and vitamin B6 tended to increase following LSG within the first year after intervention. Also, parameters of protein status (albumin, transferrin, cholinesterase, and total protein) decreased. After surgery, bioimpedance measures indicated a reduction of total body fat, but also of body cell mass.

CONCLUSIONS

Preoperative micronutrient deficiencies were common in morbid obese individuals scheduled for LSG. LSG had a modest effect on micronutrient status by further reducing iron, vitamin B12, vitamin B6, and folate within the first year after intervention. Our data suggest that especially obese patients with preoperative deficits require control and supplementation of micronutrients and protein in the postoperative period.

Bioimpedance and bioimpedance vector analysis in patients with anorexia nervosa

OBJECTIVE

The utility of bioelectrical impedance analysis (BIA) in patients with anorexia nervosa (AN) is imperfectly defined. Furthermore, any advantage accrued by BIA with vector analysis (BIVA) is unknown.

METHOD

We conducted a retrospective analysis of 57 women with AN admitted to our service who underwent BIA and BIVA. Twenty-seven women were observed during short-term (3 weeks) and 13 women during longer-term (3 months) weight gain.

RESULTS

Bioelectrical impedance analysis produced implausible results in 47% of the patients. BIVA demonstrated low body cell mass and highly variable extracellular water (ECW) volume, ranging from volume contraction to volume expansion on admission and during treatment. BIVA suggested that short-term weight gain predominantly consisted of ECW volume, whereas longer-term weight gain resulted in increased hydrated body cell mass.

CONCLUSION

Conventional BIA has little utility in these patients. However, BIVA could be a suitable alternative in the medical management reflecting ECW volume changes and later genuine tissue mass increases.

Estimate of body water compartments and of body composition in maintenance hemodialysis patients: comparison of single and multifrequency bioimpedance analysis

OBJECTIVE

The goal of this study was to compare the adequacy of single and multifrequency bioimpedance analysis (BIA) to evaluate body water compartments, body composition, and nutritional status in maintenance hemodialysis patients.

DESIGN

Cross-sectional study.

SETTING

University-based hemodialysis unit.

PATIENTS

Nineteen patients (12 male, 7 female), ages 28 to 82 years (mean, 58.9), treated with maintenance hemodialysis (MHD) for 0.5 to 15 years (mean, 7.3).

INTERVENTION

This was a noninterventional study. Patients gave their informed consent to the diagnostic procedures performed.

MAIN OUTCOME MEASURES

Total body water (TBW), extracellular water (ECW), fat-free mass (FFM), and body cell mass (BCM) volumes were estimated with single-frequency (sf BIA) and multifrequency (mf BIA) plethysmographs before and after a midweek dialytic session. Predialysis TBW also was estimated from anthropometric data (e TBW). Serum albumin, prealbumin and myoglobin, and creatinine index were determined as indicators of nutritional status and muscle mass.

RESULTS

Sf BIA and mf BIA gave very similar results for TBW volumes. A high linear correlation was also found between e TBW values and both sf TBW and mf TBW; however, a statistically significant difference was found between e TBW and sf and mf TBW. Sf BIA and mf BIA gave quite different results for ECW, particularly when measured predialysis. The results obtained for FFM indicate a poor agreement between sf and mf BIA. The agreement was better when FFM was measured postdialysis. The values of BCM, either measured predialysis or postdialysis, indicate a significant difference between sf and mf BIA. FFM and BCM estimated with mf BIA had a closer correlation with creatinine index than sf BIA. mf BCM had also a higher correlation with serum myoglobin, which is produced by muscle cells.

CONCLUSIONS

TBW can be estimated with enough confidence from either sf or mf BIA at any time. On the contrary, the results of ECW are significantly different with sf and mf BIA when measured predialysis. Thus, it seems more convenient to perform BIA after dialysis, in particular when assessing the "ideal" body weight. The measurements of FFM and BCM, obtained with either sf or mf BIA, are correlated with different indicators of nutritional status. In particular, mf BCM seems more appropriate than sf BCM for estimating muscle mass.