A Blood Test for the Diagnosis of Multiple Sclerosis.

Multiple sclerosis (MS) is an autoimmune chronic disease characterized by inflammation and demyelination of the central nervous system (CNS). Despite numerous studies conducted, valid biomarkers enabling a definitive diagnosis of MS are not yet available. The aim of our study was to identify a marker from a blood sample to ease the diagnosis of MS. In this study, since there is evidence connecting the serotonin pathway to MS, we used an ELISA (Enzyme-Linked Immunosorbent Assay) to detect serum MS-specific auto-antibodies (auto-Ab) against the extracellular loop 1 (ECL-1) of the 5-hydroxytryptamine (5-HT) receptor subtype 2A (5-HT2A). We utilized an ELISA format employing poly-D-lysine as a pre-coating agent. The binding of 208 serum samples from controls, both healthy and pathological, and of 104 serum samples from relapsing-remitting MS (RRMS) patients was tested. We observed that the serum-binding activity in control cohort sera, including those with autoimmune and neurological diseases, was ten times lower compared to the RRMS patient cohort (p = 1.2 × 10-47), with a sensitivity and a specificity of 98% and 100%, respectively. These results show that in the serum of patients with MS there are auto-Ab against the serotonin receptor type 2A which can be successfully used in the diagnosis of MS due to their high sensitivity and specificity.

Nutritional indicators and metabolic alterations in outpatients with anorexia nervosa: a retrospective study.

PURPOSE: In patients living with Anorexia Nervosa (AN), dehydration and haemoconcentration, may prevent a correct interpretation of laboratory nutritional parameters. Our study aims to evaluate if some indicators of disease severity, as body mass index (BMI), Phase Angle (PhA) and months of amenorrhea may be predictors of metabolic alterations (serum albumin, liver enzymes). METHODS: In 154 outpatients with AN, case history was collected, and anthropometric and laboratory parameters measured. Patients were divided according to the following tertiles (T) of BMI, duration of amenorrhea and PhA: (1) BMI (T1 < 15.6; T2 15.6-16.8; T3 > 16.8 kg/m2); (2) Amenorrhea duration (T1 < 7; T2 7-14; T3 > 14 months); (3) PhA value (T1 < 4.64; T2 4.64-5.35; T3: > 5.35°). ROC curves were used to determine which of these three indicators (BMI, PhA and amenorrhea duration) might better identify patients belonging to Group A or B (less than 3 or more metabolic abnormalities). RESULTS: The most frequent registered metabolic alterations were for alkaline phosphatase (ALP), alanine aminotransferase, cholesterol and hemoglobin. Aspartate aminotransferase, ALP and gamma glutamyl transferase abnormalities were frequent in the first tertiles of all the three indicators. Albumin was low in the T1 of BMI and PhA. No differences in nutritional alterations emerged according to amenorrhea duration. PhA had the best performance (AUCs: 0.721) in identifying patients with 3 or more abnormalities, with the optimal cut-off value of 4.5°. CONCLUSIONS: Our data confirmed PhA as the more reliable predictor of metabolic alterations, followed by BMI and amenorrhea duration, especially in the first tertile. EVIDENCE-BASED MEDICINE: Level 2.

Evaluation of nutritional adequacy in adult patients with Crohn's disease: a cross-sectional study.

PURPOSE: Inadequate oral intake may play an important role in the onset of malnutrition in patients with Crohn's disease (CD). The aims of this cross-sectional study were: (1) to compare dietary intake in clinically active and quiescent CD patients, and (2) to assess patients' nutritional adequacy relative to the dietary reference values (DRVs) for the Italian population using LARN (Livelli di Assunzione di Riferimento di Nutrienti ed energia per la popolazione italiana). METHODS: Patients aged between 18 and 65 years with a diagnosis of CD were recruited. All participants underwent anthropometry and were instructed to fill in a 3-day food record. Disease activity was clinically defined using the Crohn's disease activity index (CDAI). RESULTS: Overall, 117 patients, 71 males and 46 females, with a mean age of 39.6 ± 13.8 years and a mean body weight of 65.4 ± 11.8 kg, were ultimately included. Our findings showed that the amount of nutrients was similar between patients with active and quiescent disease. The mean intake of macronutrients was adequate, except for fiber, while dietary micronutrients were insufficient. Median intakes of sodium, phosphorus, and fluorine met LARN recommendations in both sexes, and the DRVs were accomplished by many patients (53/117; 104/117 and 98/117, respectively). Interestingly, dietary amounts of iron and zinc were barely acceptable in males but not in females. However, a few of the patients (< 15) met the LARN for potassium, calcium, and magnesium, regardless of sex and CDAI. With respect to vitamins, no relevant difference was found between the active and quiescent groups, and none of them met recommended values in both sexes. CONCLUSIONS: This study showed that the assessment of dietary intake can be crucial for optimizing dietary intervention with focused nutrition counseling, to improve nutritional status in CD patients.

Accuracy of predictive equations for estimating resting energy expenditure in obese adolescents.

OBJECTIVE: To compare resting energy expenditure (REE) measured by indirect calorimetry with REE predicted using different equations in obese adolescents. STUDY DESIGN: We recruited 264 obese patients (body mass index ranging from 30.0-70.0 kg/m(2)) between 14 and 18 years of age. Data were obtained comparing measured and predicted REE derived from published equations for normal weight and obese adolescents. The average differences between measured and predicted REE, as well as the accuracy at ± 10% level, were evaluated. RESULTS: Evaluating the mean REE in 109 males (1938 ± 271 kcal/d) and 155 females (2569 ± 459 kcal/d), we found that the Lazzer equation in males had the smallest difference between measured and predicted REE; in females the Henry-1, Food and Agriculture Organization/World Health Organization/United Nations University, Schmelze, and Lazzer equations were the most accurate. The prediction accuracy was considered adequate within ± 10%. CONCLUSIONS: REE predictive equations developed in obese patients and for specific age groups are more suitable than those for the general population. Inaccuracy of predicted REE could affect dietary prescription appropriateness and, consequently, dietary compliance in this age group.

The Anxiety Burden in Patients with Chronic Intestinal Failure on Long-Term Parenteral Nutrition and in Their Caregivers.

Background and aims: Home parenteral nutrition (HPN) is a life-saving treatment for patients affected by chronic intestinal failure (CIF). Both this clinical condition and its therapy require radical lifestyle modifications, affecting life quality and psychological balance in patients as well as family members. Patient psychological burden has rarely been taken into consideration, not to mention that of caregivers. This study aims to evaluate the levels of anxiety in CIF patients on HPN, and their caregivers, consequently determining their impact on the psychological and physical aspects. Methods: After a brief introductory interview, adult patients on HPN for CIF and their caregivers were asked to fill in the HAMA-A questionnaire. Results: Fifty patients and their respective caregivers were enrolled. Mean HAMA-A scores were similar in patients and caregivers and testified the presence of a mild to severe impact of CIF and HPN in both groups, with a significantly higher impact on female patients and caregivers. After adjusting age, education level, duration of CIF and HPN dependence, and degree of kinship, no differences were revealed in the scores. Conclusions: The study confirms that CIF patients on HPN and their caregivers have a significant anxiety burden independently from the duration of the disease, therefore needing appropriate support.

Exploring Adiponectin in Autosomal Dominant Kidney Disease: Insight and Implications.

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a common monogenic disorder characterized by renal cysts and progressive renal failure. In kidney diseases, adipose tissue undergoes functional changes that have been associated with increased inflammation and insulin resistance mediated by release of adipokines. Adiponectin is involved in various cellular processes, such as energy and inflammatory and oxidative processes. However, it remains to be determined whether adiponectin is involved in the concomitant metabolic dysfunctions present in PKD. In this scenario, we aimed to analyze: (a) PPARγ, ADIPOQ, ADIPOR1 and ADIPOR2 gene variations in 92 ADPKD patients through PCR-Sanger sequencing; and (b) adiponectin levels and its oligomerization state by ELISA and Western Blot. Our results indicated that: (a) 14 patients carried the PPARγ SNP, 29 patients carried the ADIPOQ SNP rs1501299, and 25 patients carried the analyzed ADIPOR1 SNPs. Finally, 82 patients carried ADIPOR2 SNPs; and (b) Adiponectin is statistically lower in ADPKD patients compared to controls, and further statistically lower in ESRD than in non-ESRD patients. An inverse relationship between adiponectin and albumin and between adiponectin and creatinine and a direct relationship between adiponectin and eGFR were found. Interestingly, significantly lower levels of adiponectin were found in patients bearing the ADIPOQ rs1501299 SNP and associated with low levels of eGFR. In conclusion, adiponectin levels and the presence of ADIPOQ rs1501299 genotype are significantly associated with a worse ADPKD phenotype, indicating that both could potentially provide important insights into the disease. Further studies are warranted to understand the pathophysiological role of adiponectin in ADPKD patients.

Chronic renal impairment and DDAH2-1151 A/C polymorphism determine ADMA levels in type 2 diabetic subjects.

BACKGROUND: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS). Increased levels of ADMA cause impaired vasodilation, leading to endothelial dysfunction and a higher risk for cardiovascular events. In patients with a chronic kidney disease, increased ADMA levels are reported to play a role in the pathogenesis of accelerated atherosclerosis and are an independent risk marker leading to end-stage renal disease and mortality. Circulating ADMA is metabolized by the action of dimethylarginine dimethylamino hydrolase (DDAH) and DDAH2 isoform is the most prevalent in tissues expressing endothelial NOS. DDAH and NOS are co-expressed in the same kidney regional sites supporting the hypothesis that a strict and specific regulation of intracellular ADMA levels is crucial for NO generation in the kidney. Starting from these findings, the study aims to investigate the role of DDAH2 gene promoter polymorphism at position -1151 A/C in determining the levels of ADMA in type 2 diabetic patients (T2DM) with chronic renal impairment. METHODS: Three groups of carefully selected subjects of both sexes were enrolled and compared. The first group (control subjects) comprised 286 non-diabetic subjects (mean age 55.8 ± 11.4 years), the second group (T2DM uncomplicated subjects) was made up of 322 T2DM subjects without complications (mean age 64.9 ± 9.6 years) whereas the third group (T2DM CRF subjects) included 110 T2DM patients with chronic renal impairment. The rs805304 DDAH2-1151 A/C promoter polymorphism was determined by a polymerase chain reaction-restriction fragment length polymorphism approach. Results T2DM CRF subjects showed significant increased plasma levels of ADMA with respect to those of T2DM uncomplicated subjects and control subjects (0.51 versus 0.39 versus 0.37 µmol/L, P = 0.002, respectively). Analysis of variance showed an interaction between DDAH2-1151 C carrier and groups on ADMA plasma levels (F = 4.36; P < 0.05). ADMA plasma levels were also dependent on groups (F = 4.96; P < 0.01). CONCLUSIONS: Our work demonstrates that rs805304 DDAH2-1151 polymorphism plays a central role in determining ADMA in diabetic renal impairment, where patients with DDAH2-1151 C carriers showed the highest ADMA levels. This unfavourable genetic profile is highlighted by pathological kidney conditions such as diabetic CRF. These findings could open new insights on the pathways involving ADMA/DDAH/NOS in the development and progression of chronic renal impairment and therefore of the other micro- macrovascular diabetic complications.

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.

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 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.

Evaluation of the Nutritional Status of Gaucher Disease Type I Patients under Enzyme Replacement Treatment.

(1) Background: Gaucher disease (GD) is a rare lysosomal storage disease. The few studies analyzing Resting Energy Expenditure (REE) in GD involved mainly untreated patients and supported a hypermetabolic condition possibly due to the associated inflammatory state. Definitive conclusions could not be drawn also because of the heterogeneity and the small size of the samples investigated. In order to expand current knowledge concerning, in particular the condition of patients under Enzyme Replacement Therapy (ERT), we evaluated the nutritional status of a relatively large sample of GD patients followed at Federico II University Hospital in Naples, Italy. (2) Methods: The study, having a cross-sectional design and involving 26 patients on ERT, included routine biochemical analyses, bioelectrical impedance analysis, indirect calorimetry, and administration of food frequency and physical activity questionnaires. The results in GD patients were compared with those from an appropriate control group. (3) Results: GD patients had normal biochemical parameters in 80% of cases, except for HDL-cholesterol, consumed a hyper-lipidic diet, and had a 60% prevalence of overweight/obesity. Body composition did not differ between patients and controls; however, measured REE was significantly lower than predicted and was reduced in comparison with the healthy controls. (4) Conclusions: This study provided novel elements to the present knowledge about REE and the nutritional status of GD patients under ERT. Its results warrant confirmation in even larger GD population samples and a more in-depth investigation of the long-term effects of treatment superimposed on the basic pathophysiological disease condition.

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.

Mass spectrometry measurement of plasma hepcidin for the prediction of iron overload.

BACKGROUND: Hepcidin has emerged as the primary regulator of iron homeostasis. Previous studies on assessing urinary hepcidin are limited. We developed a method for quantifying hepcidin-25 (Hep-25) in plasma using surface-enhanced laser-desorption-ionization time-of-flight mass spectrometry (SELDI-TOF/MS) and a 25-AA peptide as reference standard. The aims of the study were 1) to assess the performance of this method in different conditions of iron metabolism disorders; 2) to assess the diagnostic validity of non-invasive serum biomarkers in the identification of iron overload. METHODS: Validation of the method was performed in 10 patients with type I hemochromatosis (HE) and in 177 subjects previously enrolled in a general population epidemiological study. Among the latter group, 17 had non-alcoholic fatty liver disease, 10 had chronic hepatitis C, and 150 subjects had normal ultrasound, normal liver function tests (LFTs), an alcohol intake < 20 g ethanol/day and were negative for the C282Y mutation. The following biomarkers were assayed in each case: plasma Hep-25, C282Y and H63D mutations of the HFE gene; serum iron, ferritin (SF), transferrin saturation, transaminases, γ-glutamyltransferase (GGT), glucose, insulin, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides. RESULTS: Plasma Hep-25 concentrations were higher in HCV+ patients (26.3 ± 7.2 nmol/L) than in controls, and correlated positively with SF (p < 0.001). H63D heterozygous subjects revealed a pattern of iron overload that was significantly higher than H63D wild type subjects. Analyzing the data with the Biomarker Pattern 5.0.2. software to identify the most significant biomarkers for discriminating between HE cases and controls allowed us to produce an algorithm with four terminal nodes, which included glucose > 4.8 mmol/L and Hep-25/SF ratio ≤ 6.6 as the main splitters. These variables enabled the correct diagnosis of HE with 100% sensitivity, 93% specificity and an area under the receiver operating characteristic (ROC) curve of 0.993. CONCLUSIONS: Our plasma Hep-25 mass spectrometry method yields measurements that reflect pathological and genetic influences; simple non-invasive biomarkers (Hep-25/SF ratio and glucose) can predict the presence of HE.

Prediction of resting energy expenditure in healthy older adults: A systematic review.

BACKGROUND & AIMS: Estimates of energy requirements, based on measured or predicted resting energy expenditure (REE), are needed to avoid undernutrition or overnutrition (and their clinical consequences) in elderly subjects. The aims of this systematic review were to evaluate the prediction accuracy of REE in healthy elderly subjects and to ascertain which equation is more reliable at group level and/or individual level. METHODS: Studies assessing prediction of REE in general elderly population were systematically searched using PubMed, EMBASE, Web of Science and CINAHL until March 2020. Prediction accuracy of REE was assessed at both group (bias) and individual (precision) level for each equation. RESULTS: Fourteen studies met the inclusion criteria of this systematic review. Bias was reported in 8 papers and calculated in another 5 from absolute values. There was a prevalent tendency towards an overestimation of REE across the studies. The least bias was observed for the Mifflin (-0.3%) and Harris-Benedict (+2.6%) equations, with values above 5% for the FAO/WHO/UNU, Fredrix and Muller equations. Precision widely varied between studies for the same equation. The higher precision was observed using the Harris-Benedict equation (~70%), while the Henry and Mifflin equations provided estimates within 10% of measured values in 65% and 61% of elderly individuals, respectively. CONCLUSIONS: None of the prediction equations considered provides accurate and precise REE estimates in healthy older adults. However, the best prediction is given by the Mifflin equation at group level and by the Harris-Benedict equation at individual level. Further studies with strong quality design are needed to evaluate the variability and accuracy of REE in the elderly general population.

Bioimpedance phase angle in elite male athletes: a segmental approach.

OBJECTIVE: Phase angle (PA), a bioelectrical impedance analysis (BIA) parameter, has proven to be a proxy of body cell mass in athletes, but very few data are available on its segmental evaluation (upper and lower limbs). Therefore, we aimed to assess whether whole-body and segmental PA varied among elite male athletes of different sports and compared these to control groups. Additionally, we investigated its relationship with anthropometric and body composition parameters. APPROACH: Elite athletes practicing cycling, water polo and ballet dance aged 18-40 years underwent anthropometric and BIA measurements. PA (whole-body and upper and lower limbs) was considered as raw BIA variable. Data were also compared with healthy subjects with similar characteristics who served as control groups. MAIN RESULTS: Participants included three groups of male athletes: 18 cyclists (age 28.6 ± 3.4 years; weight 70.6 ± 5.4 kg; BMI 21.5 ± 1.4 kg m2), 20 water polo players (age 23.9 ± 4 years; weight 89.0 ± 5.2 kg; BMI 25.9 ± 1.9 kg m2) and 18 ballet dancers (age 19.2 ± 1.3 years; weight 63.3 ± 5.8 kg; BMI 20.8 ± 1.0 kg m2) and three groups of healthy control subjects each of which similar for general characteristics (one to one) to the previous ones. Both whole-body and limb PAs were significantly higher in athletes compared to their respective controls, whereas no differences were found among sport groups. PA was positively correlated with BMI and fat-free mass (FFM) more in athletes than in controls and FFM was the main determinant. SIGNIFICANCE: PA may represent a useful proxy parameter of soft tissue mass quality, directly related to physical activity level. Furthermore, the direct evaluation of segmental PA among athletes practicing different sports may be useful for assessing and monitoring the differences among athletes and changes due to training.

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.

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.

Body Composition and Bioelectrical-Impedance-Analysis-Derived Raw Variables in Pole Dancers.

Few data are available on the body composition of pole dancers. Bioelectrical impedance analysis (BIA) is a method that is used to estimate fat-free mass (FFM) and fat mass (FM), while raw BIA variables, such as the impedance ratio (IR) and phase angle (PhA), are markers of body cell mass and the ratio between extracellular and total body water. The aim of this study was to evaluate the body composition of pole dancers compared to controls, in particular, those raw BIA variables that are considered as markers of muscle composition. Forty female pole dancers and 59 controls participated in the study. BIA was performed on the whole body and upper and lower limbs, separately, at 5, 50, 100 and 250 kHz. The FFM, FFM index, FM and body fat percentage (BF%) were predicted. The bioelectrical impedance indexes IR and PhA were also considered. Pole dancers exhibited higher FFMI and BI indexes and lower BF%. PhA was greater and IRs were smaller in pole dancers than in controls for the whole body and upper limbs. Considering the training level, FFM, whole-body IR and PhA were higher in the professionals than non-professionals. Raw BIA variables significantly differed between the pole dancers and controls, suggesting a higher BCM; furthermore, practicing pole dancing was associated with a greater FFM and lower FM.

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.