Could BIA-derived phase angle predict health-related musculoskeletal fitness? A cross-sectional study in young adults.

OBJECTIVES: To our knowledge, little evidence exists on the relationships between body composition and health-related physical fitness; in particular, musculoskeletal fitness. Bioimpedance index phase angle (bioelectrical impedance analysis raw variables) is a candidate predictor of health-related fitness, a marker of fat-free and body cell mass, respectively. The aim of this study was to evaluate body composition, raw bioelectrical impedance analysis variables, and health-related fitness in young adults and investigate their mutual relationships to identify predictors of muscle strength. METHODS: The study included 229 young adults (115 men and 114 women; 24.2 ± 3 y; body mass index 19-30 kg/m²). Anthropometry was measured with standardized procedures. Whole-body BIA (50 kHz) was performed for impedance and phase angle. Predictive equations estimated fat-free mass and percentage body fat. The bioimpedance index was calculated as stature²/impedance. Musculoskeletal fitness was assessed by handgrip strength, standing broad jump, squat jump, and countermovement jump. RESULTS: In both sexes, health-related fitness had stronger associations with body composition than stature or weight. Handgrip strength was related to fat-free mass and bioimpedance index, while an inverse association with percent body fat emerged for standing broad jump, squat jump and countermovement jump. Phase angle is directly correlated with handgrip strength, standing broad jump, squat jump, and countermovement jump. In multiple regression analysis phase angle was an independent predictor of all health-related fitness tests, along with fat-free mass (or bioimpedance index) for handgrip strength, and with sex and percent body fat for the three jump tests. CONCLUSIONS: The present study provided consistent information on the relationships between body composition and health-related fitness in young adults. Phase angle emerged as a significant predictor of all health-related fitness measures and might be useful for a more consistent assessment of musculoskeletal fitness.

High Nutritional Risk Is Associated with Poor Functional Status and Prognostic Biomarkers in Stroke Patients at Admission to a Rehabilitation Unit.

Considering that malnutrition (undernutrition) is common in stroke patients and may negatively impact body function, the aim of this study was to determine the relationship between nutritional risk and functional status in stroke patients at admission to a rehabilitation unit. Nutritional risk was assessed using the Geriatric Nutritional Risk Index (GNRI), the Prognostic Nutritional Index (PNI) and the Controlling Nutritional Status (CONUT) score. Functional status was assessed using the Barthel Index, the modified Rankin Scale, the Trunk Control Test and the Sitting Balance Scale, and cognitive function was assessed using the Short Portable Mental Status Questionnaire. C-reactive protein, fibrinogen and D-dimer were also evaluated as established prognostic biomarkers. Stroke patients (n = 245; age 69.7 ± 12.8 years; 47%, women; 82% ischemic stroke) at admission to a rehabilitation unit were included in this study. A high prevalence of nutritional risk was detected with each tool and was found to be greater using the GNRI and in patients aged ≥75 years. Multiple logistic regression analysis showed that age and dysphagia were independent predictors of high nutritional risk. High risk groups performed worse on all functional tests compared to the low-risk groups (p < 0.05). Nutritional risk with each tool was associated with functional and cognitive statuses (with the highest correlation being with the Trunk Control Test). Significant associations were also found with C-reactive protein, fibrinogen and D-dimer. In conclusion, a high nutritional risk, as evaluated with the GNRI, the PNI and the CONUT score, was detected in stroke patients at admission to a rehabilitation unit. High nutritional risk was associated with functional status and with predictors of clinical outcomes (and specifically in older patients).

Amino acid profiles, disease activity, and protein intake in adult patients with Crohn's disease.

Introduction: Crohn's disease (CD) is an immune-mediated inflammatory disorder of the gastrointestinal tract with a relapsing-remitting course. Amino acids (AAs) may play critical roles in the intestinal manifestations of disease, due to their involvement in many metabolic and immune functions. The present study aimed to explore serum AA concentrations in adult patients with CD, looking into their variations due to disease activity, surgery and protein content of diet. Eventually, the link between AAs and inflammatory markers was also assessed. Methods: Consecutive adult patients aged 18-65 years with diagnosis of CD were recruited. All participants underwent anthropometry and were instructed to fill in a 3-day food record to assess protein intake. Disease activity was clinically defined using the Crohn's Disease Activity Index (CDAI), while blood samples were taken to analyze serum AA profile and inflammatory markers. Results: A total of 103 patients with CD (61 men and 42 women; age:39.9 ± 13.9 years, BMI: 23.4 ± 3.51 kg/m2) were included. Tryptophan levels were found to be remarkably decreased in most subjects, unrelated to disease activity. On the contrary, concentration of lysine, leucine, valine and glutamine decreased in active versus quiescent CD patients, while aspartic acid, glutamate and glycine increased. The latter AAs were also directly correlated with CDAI and serum interleukin (IL)- 1ß concentration. Considering the total protein intake, expressed as g/kg/body weight, we observed a reduction in some essential AAs in patients with unmet protein requirements compared to patients who met the recommendation. Discussion: In conclusion, specific AAs varied according to disease activity and protein intake, adjusted to body weight and disease status. Glu and Asp concentrations raised with increasing IL-1ß. However, extensive research is needed to understand the mechanisms underpinning the link between variation in serum AAs, disease activity and protein intake in patients with CD.

Relationship between Nutritional Risk, Clinical and Demographic Characteristics, and Pressure Ulcers in Patients with Severe Acquired Brain Injuries Attending a Rehabilitative Program.

Preliminary evidence in the literature suggests a high prevalence of malnutrition (undernutrition) in patients with severe acquired brain injuries (sABI), with an expected negative impact on clinical outcomes and pressure ulcers (PUs) in particular. In a retrospective cohort study on patients discharged from intensive care units (ICU) and admitted to an intensive rehabilitation unit (IRU), the risk of malnutrition was systematically assessed, in addition to standard clinical procedures (including PUs evaluation), using two different tools: the Malnutrition Universal Screening Tool (MUST) and the Controlling Nutritional Status (CONUT) tool. Eighty-eight patients were included in the analysis. A high proportion (79.5%) of patients with sABI suffered from PUs, being older and more frequently men, with a longer ICU stay between the event and admission to IRU, and a greater MUST score. At discharge, when compared to patients whose PUs had healed, those with persisting PUs were more often men and had the worst cognitive performance at admission. As for nutritional risk, the baseline CONUT score was identified as an independent negative predictor of PUs at discharge by the logistic regression model. In conclusion, the assessment of nutritional risk using simple standard tools may be useful in the clinical evaluation of sABI patients with PUs.

Controlling Nutritional Status (CONUT) score and the risk of mortality or impaired physical function in stroke patients: A systematic review and meta-analysis.

AIMS: The Controlling Nutritional Status (CONUT) score is a tool for assessing the risk of malnutrition (undernutrition) that can be calculated from albumin concentration, total peripheral lymphocyte count, and total cholesterol concentration. CONUT score has been proposed as a promising prognostic marker in several clinical settings; however, a consensus on its prognostic value in patients with stroke is lacking. The aim of this systematic review and meta-analysis was to evaluate the relationship between CONUT score and clinical outcomes in patients with stroke based on all current available studies. DATA SYNTHESIS: Systematic research on PubMed, Scopus and Web of Science from inception to February 2023 was performed on the association between CONUT score and clinical outcomes in patients with stroke. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses were followed. Methodological quality was evaluated using the Newcastle-Ottawa Scale quality assessment tool. Pooled effect estimation was calculated by a random-effect model. Through the initial literature search, 15 studies (all high-quality) including 16 929 patients were found to be eligible and analysed in the meta-analysis. A significant risk of malnutrition (in most studies defined by a CONUT score ≥5) was directly associated with mortality, higher risk of poor functional outcome according to the modified Rankin Scale and total infection development. Evidence was consistent for acute ischaemic stroke and preliminary for acute haemorrhagic stroke. CONCLUSION: CONUT score is an independent prognostic indicator, and it is associated with major disability and infection development during hospitalisation. PROSPERO ID: CRD42022306560.

Serum Interleukin 6, Controlling Nutritional Status (CONUT) Score and Phase Angle in Patients with Crohn's Disease.

Crohn's disease (CD) is a chronic inflammatory disorder that may occur in any segment of the gastrointestinal tract. Asymptomatic or untreated inflammation along with malnutrition can often coexist in patients with CD, impairing clinical outcomes, therefore the aim of this study was to assess the relationship between inflammation, malnutrition risk and nutritional status in CD patients. Consecutive adult CD outpatients aged 18-65 years were recruited. Disease activity was clinically defined by the Crohn's Disease Activity Index (CDAI), whilst anthropometry and phase angle (PhA) were measured. The Controlling Nutritional Status (CONUT) score was retrospectively calculated for screening malnutrition risk and blood samples were taken. A total of 140 CD patients with a mean age of 38.8 ± 13.9 years and an average weight of 64.9 ± 12.0 kg were included. Serum interleukin (IL)-6 concentration was increased in active-CD patients, unrelated to medical treatment, which was associated with CDAI and PhA. Based on the CONUT score, the prevalence of patients with moderate/severe malnutrition risk (score ≥ 5) was 10%, showing lower age, body mass index and fat mass, but higher IL-6 and IL-1ß levels than subjects classified as not at risk (score 0-1). Finally, increased IL-6 levels and reduced PhA values were identified as independent predictors of moderate/severe malnutrition risk (p < 0.05). In conclusion, IL-6 increased in active-CD patients, which was inversely correlated with PhA. Although the CONUT score might be helpful for identifying CD patients at moderate/severe risk of malnutrition, larger studies are needed to verify these results in different settings.

The Assessment of the Risk of Malnutrition (Undernutrition) in Stroke Patients.

Malnutrition is common in stroke patients, as it is associated with neurological and cognitive impairment as well as clinical outcomes. Nutritional screening is a process with which to categorize the risk of malnutrition (i.e., nutritional risk) based on validated tools/procedures, which need to be rapid, simple, cost-effective, and reliable in the clinical setting. This review focuses on the tools/procedures used in stroke patients to assess nutritional risk, with a particular focus on their relationships with patients' clinical characteristics and outcomes. Different screening tools/procedures have been used in stroke patients, which have shown varying prevalence in terms of nutritional risk (higher in rehabilitation units) and significant relationships with clinical outcomes in the short- and long term, such as infection, disability, and mortality. Indeed, there have been few attempts to compare the usefulness and reliability of the different tools/procedures. More evidence is needed to identify appropriate approaches to assessing nutritional risk among stroke patients in the acute and sub-acute phase of disease or during rehabilitation; to evaluate the impact of nutritional treatment on the risk of malnutrition during hospital stay or rehabilitation unit; and to include nutritional screening in well-defined nutritional care protocols.

Comparison of bioelectrical impedance analysis-derived phase angle in individuals with different weight status.

OBJECTIVE: Obesity is characterized not only by an increase of fat mass but also by alterations in skeletal muscle. Bioimpedance analysis (BIA)-derived phase angle (PhA) may provide specific information on the inherent characteristics of fat-free mass, and is widely used as an index of poor nutritional status. The aim of this study was to describe whether and to what extent PhA varies depending on age, sex, and body mass index (BMI) in individuals with different weight status. METHODS: We selected 1877 participants for this retrospective study (two weight status groups): 983 individuals with obesity (age 40 ± 13.9 y; BMI 39.5 ± 7.2 kg/m²) and 894 controls (age 40 ± 13.3 y; BMI 24.6 ± 2.7 kg/m²). Anthropometry and PhA at 50 kHz for the whole body were performed in all participants. RESULTS: PhA was greater in men than in women, although a decline of PhA was observed with age, which was linear in women and occurred in men after 40 y of age. On the other hand, no significant differences were observed with increasing BMI in either sex; lower values might be observed when BMI >50 kg/m². CONCLUSIONS: A more detailed appraisal of BIA-derived PhA in obesity is reported in the present study, providing basic data that might be taken into consideration in prevention and clinical nutrition. Further studies are needed to explore differences of PhA in individuals with different weight status.

Bioelectrical Impedance Analysis-Derived Phase Angle and Body Composition Are Predictors of Health-Related Fitness in Children and Adolescents with Obesity.

There is little evidence in children and adolescents with obesity of the relationships between muscle strength/cardiorespiratory fitness (both components of health-related fitness = HRF) and body composition. Body composition and HRF were studied in 281 children and adolescents with obesity to explore their mutual relationship and to identify the predictors of HRF. By performing a bioelectrical impedance analysis (BIA), the fat-free mass (FFM) and percentage of body fat (%BF) were calculated, and the phase angle (PhA) was recorded. Handgrip strength (HGS), the standard broad jump (SBJ), and five broad jumps (FIVEBJ) were considered for the assessment of muscle strength, and the six-minute walking distance (SIXMWD) for cardiorespiratory fitness. The BMI Z-score was slightly higher in boys, and the %BF was higher in girls, with no difference in the FFM. HGS, the SBJ, and FIVEBJ were greater in the male sex. After controlling for sex, HGS was associated with the FFM, and with height, weight, and absolute BMI. On the contrary, the SBJ and FIVEBJ were negatively associated with adiposity, with a weak relationship with the FFM. The SIXMWD was only poorly related to height, the BMI Z-score, and the waist-to-height ratio. These results were confirmed with a multiple regression analysis. HGS, the SBJ, and FIVEBJ were higher in the first compared to the third tertile of the PhA in both sexes. The PhA also remained a consistent predictor of HGS, the SBJ, and FIVEBJ in a multiple regression analysis. In conclusion, the following predictors have been identified for HRF: the FFM for the isometric strength of the upper limbs and adiposity indicators for the SBJ and FIVEBJ. The PhA emerged as a proxy index of muscle strength.

Perceived Difficulties in Physical Tasks and Physical Fitness in Treatment- and Non-Treatment-Seeking Youths with Obesity.

Youths with obesity are more likely to experience physical and psychosocial distress which strongly limits physical activity, with consequences on the quality of life. Most evidence of lower physical fitness and physical activity levels has been reported in treatment-seeking samples, while few data are available in community samples. Our aim was to assess whether perceived difficulties in physical tasks and physical fitness performance differed between treatment- and non-treatment-seeking youths with obesity, enrolled from a hospital (H) and a school (S). Three hundred fifty-one youths (269 from H and 82 from S) were enrolled. Sports participation, sedentary habits and perceived difficulties in physical tasks were assessed by interview. Six-minute walk test (SMWD) and long jump (LJ) were performed. BMI Z-score, sedentary time and perceived difficulties were higher in H vs. S. In addition, youths from H scored worse in SMWD and LJ. For the same BMI Z-score, the perceived difficulties and physical fitness were poorer in the H compared to the S group. The setting (H) was the stronger predictor of perceived difficulties and lower performance. Our findings underline that physical aspects imposed by obesity are more evident in treatment-seeking youths. Counseling related to perceived difficulties in physical tasks and performance is useful to treat youth with obesity with appropriate and personalized modalities.

A height-weight formula to measure body fat in childhood obesity.

BACKGROUND: The assessment of body composition is central in diagnosis and treatment of paediatric obesity, but a criterion method is not feasible in clinical practice. Even the use of bioelectrical impedance analysis (BIA) is limited in children. Body mass index (BMI) Z-score is frequently used as a proxy index of body composition, but it does not discriminate between fat mass and fat-free mass. We aimed to assess the extent to which fat mass and percentage of body fat estimated by a height-weight equation agreed with a BIA equation in youths with obesity from South Italy. Furthermore, we investigated the correlation between BMI Z-score and fat mass or percentage of body mass estimated by these two models. METHODS: One-hundred-seventy-four youths with obesity (52.3% males, mean age 10.8 ± 1.9) were enrolled in this cross-sectional study. Fat mass and percentage of body fat were calculated according to a height-weight based prediction model and to a BIA prediction model. RESULTS: According to Bland-Altman statistics, mean differences were relatively small for both fat mass (+ 0.65 kg) and percentage of body fat (+ 1.27%) with an overestimation at lower mean values; the majority of values fell within the limits of agreement. BMI Z-score was significantly associated with both fat mass and percentage of body fat, regardless of the method, but the strength of correlation was higher when the height-weight equation was considered (r = 0.82; p < 0.001). CONCLUSIONS: This formula may serve as surrogate for body fat estimation when instrumental tools are not available. Dealing with changes of body fat instead of BMI Z-score may help children and parents to focus on diet for health.

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.

Prevalence of Sarcopenia in Women with Breast Cancer.

Sarcopenia is a common finding in patients with cancer and potentially influences the patient's outcome. The aim of this study was to evaluate the prevalence of sarcopenia, according to the European Working Group on Sarcopenia in Older People, in a sample of women with breast cancer (BC) and a BMI lower than 30 kg/m2. This cross-sectional study was conducted in patients with BC, stage 0-III, and receiving therapy for BC; the women were recruited at the Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy. A control group with similar age and BMI was selected from the internal database. Anthropometry, bioimpedance analysis (BIA) and hand grip strength (HGS) were measured to detect sarcopenia. A total of 122 patients (mean age 49.3 ± 11.0 years, BMI 24.6 ± 3.0 kg/m2) and 80 healthy controls were analyzed. Sarcopenia was found in 13.9% patients with BC, while none of the subjects in the control group was sarcopenic. By comparing BC patients with and without sarcopenia and the control group, the fat-free mass of sarcopenic BC patients were significantly lower than those of both non-sarcopenic BC patients and the control (p < 0.05). The phase angle was also significantly lower in sarcopenic patients (−0.5 degrees, p = 0.048) than in the control group. Considering the prevalence of sarcopenia in patients with BC, our findings suggest the usefulness of body composition and HGS evaluation for early screening of sarcopenia to reduce the risk of associated complications.

Bioelectrical Phase Angle in Patients with Breast Cancer: A Systematic Review.

Breast cancer (BC) is the most common cancer diagnosed among women worldwide. Phase angle (PhA), a proxy measure of membrane integrity and function, has gained relevance in clinical practice and it has been suggested to be a prognostic and nutritional indicator. This systematic review aimed to explore PhA and its relationship with nutritional status and survival in BC patients. Four databases (PubMed, EMBASE, Web of Science, and CINAHL) were systematically searched until September 2021 for studies evaluating PhA in BC patients. A total of 16 studies met the inclusion criteria, where 11 were observational studies and 5 were interventional studies. Baseline PhA-value varied from 4.9 to 6.30 degrees, showing a great variability and heterogeneity across the selected studies. Available data suggested that PhA decreased by 5-15% after completing chemotherapy, and those effects might persist in the long term. However, the use of tailored nutritional and/or exercise programs during and after therapy could prevent PhA reduction and body derangement. High PhA values were found in women displaying a better nutritional status, while inconsistent data were found on survival. Therefore, further studies are needed to focus on the clinical relevance of PhA in BC patients, evaluating its association with disease outcomes and survival.

Nutritional Screening and Anthropometry in Patients Admitted From the Emergency Department.

BACKGROUND: Due to the high prevalence of malnutrition among hospitalized patients, screening and assessment of nutritional status should be routinely performed upon hospital admission. The main objective of this observational study was to evaluate the prevalence of and the risk for malnutrition, as identified by using three nutritional screening tests, and to observe whether some anthropometric and functional parameters used for nutritional evaluation were related to these test scores. METHODS: This single-center observational study included 207 patients admitted from the emergency department for hospitalization in either the internal medicine or surgery units of our institution from September 2017 to December 2018. The prevalence of malnutrition among this patient sample was evaluated by using the Nutritional Risk Screening (NRS-2002), the Subjective Global Assessment (SGA) and the Global Leadership Initiative on Malnutrition (GLIM) criteria. Body mass index (BMI), bioimpedance analysis (BIA), handgrip strength (HGS) and calf circumference (CC) assessments were also performed. RESULTS: According to the NRS-2002, 93% of the patients were at no risk or at low nutritional risk (NRS score < 3), and 7% were at a high nutritional risk (NRS score ≥ 3). On the other hand, according to the SGA, 46.3% of the patients were well-nourished (SGA-a), 49.8% were moderately malnourished (SGA-b), and 3.9% were severely malnourished (SGA-c). Finally, according to the GLIM criteria, 18% patients were malnourished. Body weight, body mass index (BMI), phase angle (PhA), CC and HGS were significantly lower in the patients with NRS scores ≥ 3, SGA-c and in patients with stage 1 and stage 2 malnutrition, according to the GLIM criteria. CONCLUSION: The NRS-2002, the SGA and the GLIM criteria appear to be valuable tools for the screening and assessment of nutritional status. In particular, the lowest NRS-2002, SGA and GLIM scores were associated with the lowest PhA and CC. Nevertheless, a weekly re-evaluation of patients with better screening and assessment scores is recommended to facilitate early detection of changes in nutritional status.

Cardiovascular and Neuronal Consequences of Thyroid Hormones Alterations in the Ischemic Stroke.

Ischemic stroke is one of the leading global causes of neurological morbidity and decease. Its etiology depends on multiple events such as cardiac embolism, brain capillaries occlusion and atherosclerosis, which ultimately culminate in blood flow interruption, incurring hypoxia and nutrient deprivation. Thyroid hormones (THs) are pleiotropic modulators of several metabolic pathways, and critically influence different aspects of tissues development. The brain is a key TH target tissue and both hypo- and hyperthyroidism, during embryonic and adult life, are associated with deranged neuronal formation and cognitive functions. Accordingly, increasing pieces of evidence are drawing attention on the consistent relationship between the THs status and the acute cerebral and cardiac diseases. However, the concrete contribution of THs systemic or local alteration to the pathology outcome still needs to be fully addressed. In this review, we aim to summarize the multiple influences that THs exert on the brain and heart patho-physiology, to deepen the reasons for the harmful effects of hypo- and hyperthyroidism on these organs and to provide insights on the intricate relationship between the THs variations and the pathological alterations that take place after the ischemic injury.

Resting energy expenditure in elite athletes: development of new predictive equations based on anthropometric variables and bioelectrical impedance analysis derived phase angle.

BACKGROUND: An accurate estimation of athletes' energy needs is crucial in diet planning to improve sport performance and to maintain an appropriate body composition. This study aimed to develop and validate in elite athletes new equations for estimating resting energy expenditure (REE) based on anthropometric parameters as well as bioimpedance analysis (BIA)-derived raw variables and to validate the accuracy of selected predictive equations. METHODS: Adult elite athletes aged 18-40 yrs were studied. Anthropometry, indirect calorimetry and BIA were performed in all subjects. The new predictive equations were generated using different regression models. The accuracy of the new equations was assessed at the group level (bias) and at the individual level (precision accuracy), and then compared with the one of five equations used in the general population or three athletes-specific formulas. RESULTS: One-hundred and twenty-six male athletes (age 26.9 ± 9.1 yrs; weight 71.3 ± 10.9 kg; BMI 22.8 ± 2.7 kg/m2) from different sport specialties were randomly assigned to the calibration (n = 75) or validation group (n = 51). REE was directly correlated with individual characteristics, except for age, and raw BIA variables. Most of the equations from the literature were reasonably accurate at the population level (bias within ±5%). The new equations showed a mean bias -0.3% (Eq. A based on anthropometric parameters) and -0.6% (Eq. B based on BIA-derived raw variables). Precision accuracy (individual predicted-measured differences within ±5%) was ~75% in six out of eight of the selected equations and even higher for Eq. A (82.4%) and Eq. B (92.2%). CONCLUSION: In elite athletes, BIA-derived phase angle is a significant predictor of REE. The new equations have a very good prediction accuracy at both group and individual levels. The use of phase angle as predictor of REE requires further research with respect to different sport specialties, training programs and training level.

Bioelectrical impedance (BIA)-derived phase angle in adults with obesity: A systematic review.

BACKGROUND & AIMS: Bioimpedance analysis-derived phase angle (PhA), as marker of body cell mass and cell integrity, might be altered in obesity, a condition which is characterized by alterations in muscle structure and function. The aim of this systematic review was to evaluate whether and to which extent PhA varies in individuals/patients with excess body weight focusing on: a) changes in PhA due to obesity; b) changes in PhA after bariatric interventions or training programs. METHODS: According to PRISMA criteria, a systematic literature search until February 2021 using PubMed, Embase, Scopus, and Web of Science was performed. Selection criteria included studies on patients with obesity without comorbidities other than metabolic diseases. RESULTS: A total of 278 articles were first identified. After removing duplicates and excluding studies that did not fulfil the inclusion criteria, the full text of the remaining 80 potentially relevant studies was examined to finally retrieve 11 cross-sectional and 10 longitudinal studies. Few studies have shown that PhA is lower in individuals/patients with obesity than in controls. The only study on the matter showed a decrease with age after the fourth decade of life. Four out of five studies reported consistently greater mean values in men than in women. In two studies PhA was lower in patients with severe obesity; in addition, Patients with low PhA had higher BMI and PhA was inversely correlated with fat mass. Longitudinal studies showed that PhA markedly decreased after bariatric surgery and slightly increased after training programs. CONCLUSIONS: Thus, a relatively low number of studies have evaluated PhA in individuals/patients with obesity with sometimes contradictory and preliminary results. PhA might be useful to evaluate muscle quality in individuals/patients with obesity but further studies are needed to more accurately associate this variable with changes in muscle structure and strength, as well as in metabolic functions.

A proposal for reference values of hand grip strength in women with different body mass indexes.

OBJECTIVE: Hand grip strength (HGS) is frequently used in clinical practice, resulting in a potential marker of nutritional status. This study aimed to develop reference values of HGS in Italian women with different categories of body mass index (BMI). Additionally, the main predictors of HGS were identified. METHODS: A cross-sectional study was conducted in Italian women between ages 16 and 55 y with different categories of BMI at the Department of Clinical Medicine and Surgery, Federico II University Hospital, Naples Italy. The whole sample was divided into tertiles according to BMI: 15 to 17.29 kg/m2 (T1), 17.3 to 19.9 kg/m2 (T2), and 20 to 25 kg/m2 (T3). Anthropometry, bioimpedance analysis, and muscle strength by an HGS test were evaluated. The cut-off values for HGS were developed for all participants and stratified by age group. Finally, a multivariate linear regression analysis was performed to assess the main predictors of HGS. RESULTS: A total of 529 women with a mean age of 23.2 ± 7.0 y and an average BMI of 18.9 ± 2.5 kg/m2 were analyzed. HGS was higher for the dominant hand than for the non-dominant hand in all BMI tertiles. On both sides, according to age groups, HGS increased with increasing age in T1 and T3, whereas it increased in the women between ages 20 and 30 y in T2 only. Multivariate linear regression analysis showed that predictors of HGS varied according to tertiles. Specifically, we found that body weight (R2 = 0.252) was the main predictor in T1, whereas phase angle (PhA) was the main determinant in both T2 (R2 = 0.240) and T3 (R2 = 0.216). CONCLUSION: This study defined the normal reference values of HGS in Italian women with different BMI ranges, stratifying the sample group by age. Additionally, the main predictors of HGS were assessed for each BMI tertile. In primary malnutrition (T1), the main predictor of HGS was body weight, whereas in the other two tertiles (T2, T3), the PhA was the main predictor of HGS.

New predictive equations for estimating resting energy expenditure in subjects with normal weight and overweight.

OBJECTIVE: The aim of this study was to develop and validate new predictive equations for estimating resting energy expenditure (REE) in subjects with normal weight and overweight, considering anthropometric parameters as well as raw variables from bioimpedance analysis (BIA). METHODS: Adult participants with normal weight and overweight were recruited and randomly split into calibration and validation groups. Indirect calorimetry (IC) and BIA were performed in all subjects. New predictive equations were developed using the following models: model 1 with age, weight, stature, and body mass index (BMI) as predictors; and model 2: model 1 + raw BIA variables (bioimpedance index and phase angle). The accuracy of the new equations at both the group (bias) and individual (within ±10%) levels was tested in the validation group. Three published predictive equations were also compared, with the REE values measured by IC. RESULTS: A total of 2483 adults were included for developing and validating the new equations. All selected formulas, including the new ones, showed a bias of <5% in estimating REE at the group level. Accuracy at the individual level was slightly higher for the new equations, especially for the equation based on raw BIA variables (men = 70.3%; women = 72.3%). CONCLUSIONS: Compared to the equations in the literature, the new equations showed good accuracy at both the group and individual levels, with a slight improvement in individual accuracy for the formula including raw BIA variables. However, future research is required to verify the role of the raw BIA variables in predicting REE in subjects with normal weight and overweight.