Specific BIVA recognizes variation of body mass and body composition: Two related but different facets of nutritional status

Effect of Physical Training on Body Composition in Brazilian Military

The military are selected on the basis of physical standards and are regularly involved in strong physical activities, also related to particular sports training. The aims of the study were to analyze the effect of a 7-month military training program on body composition variables and the suitability of specific ‘bioelectrical impedance vector analysis’ (spBIVA), compared to DXA, to detect the changes in body composition. A sample of 270 male Brazilian cadets (19.1 ± 1.1 years), composed of a group practicing military physical training routine only (MT = 155) and a group involved in a specific sport training (SMT = 115), were measured by body composition assessments (evaluated by means of DXA and spBIVA) at the beginning and the end of the military routine year. The effect of training on body composition was similar in SMT and MT groups, with an increase in LST. DXA and spBIVA were correlated, with specific resistance (Rsp) and reactance (Xcsp) positively related to fat mass (FM), FM%, LST, and lean soft tissue index (LSTI), and phase angle positively related to LST and LSTI. Body composition variations due to physical training were recognized by spBIVA: the increase in muscle mass was indicated by the phase angle and Xcsp increase, and the stability of FM% was consistent with the unchanged values of Rsp. Military training produced an increase in muscle mass, but no change in FM%, independently of the sample characteristics at baseline and the practice of additional sports. SpBIVA is a suitable technique for the assessment of body composition in military people.

Body composition in patients with rheumatoid arthritis: a narrative literature review

There is growing interest in the alterations in body composition (BC) that accompany rheumatoid arthritis (RA). The purpose of this review is to (i) investigate how BC is currently measured in RA patients, (ii) describe alterations in body composition in RA patients and (iii) evaluate the effect on nutrition, physical training, and treatments; that is, corticosteroids and biologic Disease Modifying Anti-Rheumatic Disease (bDMARDs), on BC in RA patients. The primary-source literature for this review was acquired using PubMed, Scopus and Cochrane database searches for articles published up to March 2021. The Medical Subject Headings (MeSH) terms used were 'Arthritis, Rheumatoid', 'body composition', 'sarcopenia', 'obesity', 'cachexia', 'Absorptiometry, Photon' and 'Electric Impedance'. The titles and abstracts of all articles were reviewed for relevant subjects. Whole-BC measurements were usually performed using dual energy x-ray absorptiometry (DXA) to quantify lean- and fat-mass parameters. In RA patients, lean mass is lower and adiposity is higher than in healthy controls, both in men and women. The prevalence of abnormal BC conditions such as overfat, sarcopenia and sarcopenic obesity is significantly higher in RA patients than in healthy controls; these alterations in BC are observed even at an early stage of the disease. Data on the effect treatments on BC in RA patients are scarce. In the few studies published, (a) creatine supplementation and progressive resistance training induce a slight and temporary increase in lean mass, (b) exposure to corticosteroids induces a gain in fat mass and (c) tumour necrosis factor alpha (TNFα) inhibitors might be associated with a gain in fat mass, while tocilizumab might be associated with a gain in lean mass. The available data clearly demonstrate that alterations in BC occur in RA patients, but data on the effect of treatments, especially bDMARDs, are inconsistent and further studies are needed in this area.

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

OBJECTIVE

The study objective is to propose bioelectrical impedance vector analysis (BIVA) ellipses for the population and investigate its use to assess nutritional status through the BMI/age ratio and the cardiovascular risk through waist circumference (WC).

DESIGN

Age, weight, height and WC were recorded, along with the values of resistance (R), reactance (Xc) and phase angle (PA) by impedance. Student's t test and ANOVA were applied to ascertain the significance between means and a specific programme was applied to investigate the significance between ellipses.

SETTING

Fortaleza, Brazil.

PARTICIPANTS

A total of 467 students from public schools participated in the study: 120 children and 347 adolescents were evaluated, with respective means of age, weight and height of 8·2 years, 27·6 kg and 1·29 m and 12·7 years, 48·6 kg and 1·53 m, respectively.

RESULTS

The mean values of R/H, Xc/H and PA were 569·0 and 424·7 Ohm/m, 59·1 and 50·4 Ohm/m, and 5·9º and 6·8º for children and adolescents, respectively. The mean vectors for R/H and Xc/H show significant differences between for both age ranges and are inversely proportional to the BMI/A. As for WC, individuals without cardiovascular risk had higher R/H and lower Xc/H, but Xc and R in participants without cardiovascular risk were greater than with cardiovascular risk.

CONCLUSIONS

It was possible to propose confidence and tolerance BIVA ellipses for children and adolescent's clinical evaluation. The method was also suitable to identify cardiovascular risk ellipses in these age groups, but it was not possible to draw nutritional classifications ellipses by BMI/age data.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Association between self-perceived body image and body composition between the sexes and different age classes

OBJECTIVES

The aim of this study was to investigate the association between self-perceived body image and body composition in the sexes and in different age classes.

METHODS

The sample consisted of 632 young adults (238 men and 394 women; 22.8 ± 2.3 y of age), and 162 middle-aged and elderly adults (96 men and 66 women; 61.4 ± 7.6 y of age). The Williamson's figure scale was used to evaluate current body size. Anthropometric measurements (height, weight and waist, arm and calf circumferences) were taken, and body mass index was calculated. Specific bioelectrical impedance vector analysis was applied to evaluate body composition.

RESULTS

The findings suggest that in both age classes, current body size was positively correlated with weight, body mass index, and vector length, indicative of the percentage of fat mass, but not with phase angle, indicative of the intracellular/extracellular water ratio and a proxy of muscle mass. The association was similar between men and women, but clearer in women. Confidence ellipses confirmed the strong association between the silhouettes and adiposity.

CONCLUSION

The Williamson's figure scale silhouettes appear to be a suitable technique to screen for adiposity in epidemiologic studies and for routine applications.

Association of Nutritional Assessment by Phase Angle With Mortality in Kidney Transplant Patients in an 8-Year Follow-Up

BACKGROUND

Phase angle is a bioimpedance analysis parameter that indirectly shows body cell mass. Its association with mortality has been shown in patients receiving dialysis treatment. However, assessment with mortality in kidney transplant recipients has not been studied previously.

METHODS

We examined 158 kidney transplant recipients who underwent bioimpedance analysis 8 years ago in a cross-sectional study. We contacted them again and investigated the presence of cardiovascular events, cancer, angina pectoris, and claudication. Data regarding mortality, graft failure, and creatinine values were collected from recipients' files.

FINDINGS

During the follow-up period, 15 recipients died, 26 lost graft function, 36 experienced cardiovascular events, and 4 developed cancer. Phase angle was significantly associated with mortality during the 8-year follow-up period of kidney transplant recipients (P < .001). The cutoff value for phase angle as a predictor of mortality was ≤5.85. Moreover, a phase angle value lower than 5.85 indicated 5.33 times higher risk of mortality.

DISCUSSION

Phase angle was a predictor of mortality in kidney transplant recipients. Since phase angle is an inexpensive, easy-to-perform, and noninvasive method, it might be considered as an additional tool to assess survival in kidney transplant recipients.

Ethnic differences in fat and muscle mass and their implication for interpretation of bioelectrical impedance vector analysis

According to the World Health Organization Expert Consultation, current body mass index (BMI) cut-offs should be retained as an international classification. However, there are ethnic differences in BMI-associated health risks that may be caused by differences in body fat or skeletal muscle mass and these may affect the interpretation of phase angle and bioelectrical impedance vector analysis (BIVA). Therefore, the aim of this study was to compare body composition measured by bioelectrical impedance analysis among 1048 German, 1026 Mexican, and 995 Japanese adults encompassing a wide range of ages and BMIs (18–78 years; BMI, 13.9–44.3 kg/m2). Regression analyses between body composition parameters and BMI were used to predict ethnic-specific reference values at the standard BMI cut-offs of 18.5, 25, and 30 kg/m2. German men and women had a higher fat-free mass per fat mass compared with Mexicans. Normal-weight Japanese were similar to Mexicans but approached the German phenotype with increasing BMI. The skeletal muscle index (SMI, kg/m2) was highest in Germans, whereas in BIVA, the Mexican group had the longest vector, and the Japanese group had the lowest phase angle and the highest extracellular/total body water ratio. Ethnic differences in regional partitioning of fat and muscle mass at the trunk and the extremities contribute to differences in BIVA and phase angle. In conclusion, not only the relationship between BMI and adiposity is ethnic specific; in addition, fat distribution, SMI, and muscle mass distribution vary at the same BMI. These results emphasize the need for ethnic-specific normal values in the diagnosis of obesity and sarcopenia.

Bioelectric impedance vector analysis (BIVA) in hospitalised children; predictors and associations with clinical outcomes

BACKGROUND

Clinical use of bioelectric impedance is limited by variability in hydration. Analysis of raw bioelectric impedance vectors (BIVA), resistance (R), reactance (Xc) and phase angle (PA) may be an alternative for monitoring disease progression/treatment. Clinical experience of BIVA in children is limited. We investigated predictors of BIVA and their ability to predict clinical outcomes in children with complex diagnoses.

METHODS

R, Xc and PA were measured (BODYSTAT Quadscan 4000) on admission in 108 patients (4.6-16.8 years, mean 10.0). R and Xc were indexed by height (H) and BIVA-SDS for age and sex calculated using data from healthy children. Potential predictors and clinical outcomes (greater-than-expected length-of-stay (LOS), complications) were recorded.

RESULTS

Mean R/H-SDS was significantly higher (0.99 (SD 1.32)) and PA-SDS lower (-1.22 (1.68))) than expected, with a wide range for all parameters. In multivariate models, the Strongkids risk category predicted R/H-SDS (adjusted mean for low, medium and high risk = 0.49, 1.28, 2.17, p = 0.009) and PA-SDS (adjusted mean -0.52, -1.53, -2.36, p = 0.01). BIVA-SDS were not significantly different in patients with or without adverse outcomes.

CONCLUSIONS

These complex patients had abnormal mean BIVA-SDS suggestive of reduced hydration and poor cellular health according to conventional interpretation. R/H-SDS was higher and PA-SDS lower in those classified as higher malnutrition risk by the StrongKids tool. Further investigation in specific patient groups, including those with acute fluid shifts and using disease-specific outcomes, may better define the clinical role of BIV.

Current technologies in body composition assessment: advantages and disadvantages

The interest in non-invasive methods of body composition assessment is on the rise in health care, especially because of its association with clinical outcomes. Technology has revolutionized our understanding of body composition abnormalities, clinical prognostication, and disease follow-up, but translation to bedside is limited, especially in terms of cost effectiveness. Computed tomography gained increased attention in cancer and sarcopenia studies, for instance. Other methods also have interesting features and applications, including bedside ultrasonography, bioelectrical impedance analysis, and dual x-ray absorptiometry. Compelling evidence indicates these methods can be used to accurately and precisely measure skeletal muscle mass, adipose tissue, and edema; diagnose malnutrition-related diseases; and aid in determining prognoses. To apply this technology properly, it is important to understand the advantages and disadvantages of each technique in specific situations of interest. This review introduces concepts and reference studies published in the scientific literature about these techniques and describes important limitations and considerations necessary to incorporate these methods into clinical practice.

Fat-free mass in adolescent athletes: Accuracy of bioimpedance equations and identification of new predictive equations

OBJECTIVES

The aims of this study were to evaluate the effect of biological maturity on body composition in Brazilian adolescent athletes, to verify the accuracy of previous bioimpedance predictive equations for estimating fat-free mass (FFM), and to develop new predictive equations, considering sexual and skeletal maturity.

METHODS

There were 318 Brazilian adolescent athletes (52% male) involved in this study. FFM was determined using single-frequency (50 kHz) bioelectrical impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA), which was used as the reference method. The adolescents were classified into skeletally mature using bone age (both sexes), and sexually mature using menarche occurrence (female). The effect of maturity on bioelectrical values was tested using bioelectrical impedance vector analysis. Three predictive BIA equations to estimate FFM were selected from the reviewed literature. Lin's concordance correlation coefficient and Bland-Altman test were used to test the concordance and accuracy of BIA equations. Stepwise multiple regression was used to develop new predictive equations, considering BIA vectors, age, skeletal, and sexual maturity.

RESULTS

DXA and BIA results showed wide limits of disagreement for FFM for all the three equations. Two new equation models were developed, including age and skeletal maturity for both sexes and menarche status for females. Both models showed high R² (males = 0.92 and females = 0.84).

CONCLUSIONS

The assessment of body composition in adolescent athletes should consider sexual (female) or skeletal (male) maturity. The newly proposed equations showed promising results in Brazilian adolescent athletes. A test in different groups and populations is necessary to evaluate the general suitability of the equations in adolescents.