Comparison of body composition measures assessed by bioelectrical impedance analysis versus dual-energy X-ray absorptiometry in the United Kingdom Biobank.

BACKGROUND: Bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) serves as common modalities for body composition assessment. This study was aimed to evaluate the agreement between BIA and DXA measures in UK Biobank. METHODS: UK Biobank participants with body fat mass (FM) and fat-free mass (FFM) estimates obtained through BIA (Tanita BC418MA) and DXA concurrently were included. Correlation between BIA and DXA-derived estimates were assessed with Lin's concordance correlation coefficients. Bland-Altman and Passing-Boblok analyses were performed to quantify the difference and agreement between BIA and DXA. Multivariable linear regression was used to identify predictors influencing the differences. Finally, prediction models were developed to calibrate BIA measures against DXA. RESULTS: The analysis included 34437 participants (female 51.4%, mean age 64.1 years at imaging assessment). BIA and DXA measurements were highly correlated (Lin's concordance correlation coefficient 0.94 for FM and 0.94 for FFM). BIA (Tanita BC418MA) underestimates FM overall by 1.84 kg (23.77 vs. 25.61, p < 0.01), and overestimated FFM overall by 2.56 kg (52.49 vs. 49.93, p < 0.01). The BIA-DXA differences were associated with FM, FFM, BMI and waist circumference. The developed prediction models showed overall good performance in calibrating BIA data. CONCLUSION: Our analysis exhibited strong correlation between BIA (Tanita BC418MA)- and DXA-derived body composition measures at a population level in UK Biobank. However, the BIA-DXA differences were observed at individual level and associated with individual anthropometric measures. Future studies may explore the use of prediction models to enhance the calibration of BIA measures for more accurate assessments in UK Biobank.

Phase Angle as a Predictor of Mortality in Older Patients with Hip Fracture.

The aim of our study is to determine if there is an association between phase angle obtained by bioelectrical impedance analysis (BIA) and mortality in older patients with fragility hip fractures. A prospective study of patients over 65 years old and hospitalized with a diagnosis of hip fracture was conducted. BIA was performed 24 to 48 h after surgery. Mortality was recorded, and the optimal phase angle cut-off value for predicting mortality was determined by using receiver operating characteristic (ROC) curves. A total of 262 patients were included. Of the patients studied, 10 (3.8%), 21 (8%), 39 (14.9%) and 53 (20.2%) died at 1, 3, 6 and 12 months after surgery, respectively. The phase angle cut-off for mortality at 12 months was 4.05° in women and 4.65° in men. A total of 94 patients (35.9%) were considered to have a low phase angle. After adjustment for possible confounders, mortality in patients with a low phase angle was 5.1 times higher at 1 month, 3.1 times higher at 3 months, 2.9 times higher at 6 months, and 2.8 times higher at 12 months. Phase angle is associated with prognosis in patients admitted for hip fracture regardless of age and comorbidities and can be positioned as a prognostic tool for mortality at 1, 3, 6 and 12 months.

Variations in bioelectrical impedance devices impact raw measures comparisons and subsequent prediction of body composition using recommended estimation equations.

BACKGROUND & AIMS: Bioelectrical impedance analysis (BIA) for body composition estimation is increasingly used in clinical and field settings to guide nutrition and training programs. Due to variations among BIA devices and the proprietary prediction equations used, studies have recommended the use of raw measures of resistance (R) and reactance (Xc) within population-specific equations to predict body composition. OBJECTIVE: We compared raw measures from three BIA devices to assess inter-device variation and the impact of differences on body composition estimations. METHODS: Raw R, Xc, impedance (Z) parameters were measured on a calibrated phantom and athletes using tetrapolar supine (BIASUP4), octapolar supine (BIASUP8), and octapolar standing (BIASTA8) devices. Measures of R and Xc were compared across devices and graphed using BIA vector analysis (BIVA) and raw parameters were entered into recommended athlete-specific equations for predicting fat-free mass (FFM) and appendicular lean soft tissue (ALST). Whole-body FFM and regional ALST were compared across devices and to a criterion five-compartment (5C) model and dual energy X-ray absorptiometry for ALST. RESULTS: Data from 73 (23.2 ± 4.8 y) athletes were included in the analyses. Technical differences were observed between Z (range 12.2-50.1Ω) measures on the calibrated phantom. Differences in whole-body impedance were apparent due to posture (technological) and electrode placement (biological) factors. This resulted in raw measures for all three devices showing greater dehydration on BIVA compared to published norms for athletes using a separate BIA device. Compared to the 5C FFM, significant differences (p < 0.05) were observed on all three equations for BIASUP8 and BIASTA8, with constant error (CE) from -2.7 to -4.6 kg; no difference was observed for BIASUP4 or when device-specific algorithms were used. Published equations resulted in differences as large as 8.8 kg FFM among BIA devices. For ALST, even after a correction in the error of the published empirical equation, all three devices showed significant (p < 0.01) CE from -1.6 to -2.9 kg. CONCLUSIONS: Raw bioimpedance measurements differ among devices due to technical, technological, and biological factors, limiting interchangeability of data across BIA systems. Professionals should be aware of these factors when purchasing systems, comparing data to published reference ranges, or when applying published empirical body composition prediction equations.

Bioelectrical impedance phase angle combined with physical function predicts pre-frailty in maintenance hemodialysis patients: a prospective study.

BACKGROUND: The prevalence of pre-frailty is notably high among maintenance hemodialysis (MHD) patients. Pre-frailty, an early and reversible condition between non-frailty and frailty, can lead to adverse outcomes such as increased unplanned hospital admissions and a higher risk of other chronic diseases. Early identification and intervention of pre-frailty in MHD patients are crucial. This study aimed to establish a simple and effective model for screening and identifying MHD patients at high risk of pre-frailty by using 50 kHz-Whole Body Phase Angle (PhA) measured by bioelectrical impedance analysis (BIA), hand grip strength (HGS), the Five-Times-Sit-to-Stand Test (FTSST), and laboratory parameters, with a specific focus on gender differences. METHODS: This prospective cross-sectional study was conducted from September to December 2023 at the Wenjiang Hemodialysis Center in the Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China. A total of 244 MHD patients, including 130 males and 114 females, were enrolled, comprising 128 non-frail and 116 pre-frail individuals. Data were collected prospectively, including demographic information, physical measurements, and laboratory test results. All participants provided informed consent before enrollment. The FRAIL scale (FS) was used to assess pre-frailty in MHD patients. Grip strength was measured using an electronic grip strength tester, physical function was assessed using the Five-Times-Sit-to-Stand Test, and whole-body phase angle was measured using the InBody S10 device. RESULTS: A total of 244 MHD patients with a mean age of 53.75 ± 0.90 years were enrolled, including 130 males with a mean age of 54.12 ± 1.26 years and 114 females with a mean age of 53.32 ± 1.29 years. ROC curve analysis showed that in male patients, the AUC of PhA for predicting pre-frailty was 0.919, with a sensitivity of 94.5% and specificity of 91.3%, and a cutoff value of 6.05°; in female patients, the AUC of PhA was 0.870, with a sensitivity of 70.5% and specificity of 90.6%, and a cutoff value of 5.25°. The AUC of FTSST for screening pre-frailty in male patients was 0.827, with a sensitivity of 62.3% and specificity of 96.2%, and a cutoff value of 12.95 s; in female patients, the AUC of FTSST was 0.784, with a sensitivity of 67.3% and specificity of 84.0%, and a cutoff value of 12.95 s. Additionally, in male patients, the combination of PhA and FTSST resulted in an AUC of 0.930, with a sensitivity of 96.4% and specificity of 81.3%; in female patients, the AUC was 0.911, with a sensitivity of 78.7% and specificity of 92.5%. CONCLUSION: PhA measured by BIA, in combination with the Five-Times-Sit-to-Stand Test, serves as an effective screening tool and predictor of pre-frailty in MHD patients. The combination of PhA and FTSST shows enhanced diagnostic value in female patients, while PhA alone is sufficient for predicting pre-frailty in male patients. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2100051111), registered on 2021-09-13.

Bioimpedance analysis predicts worsening events in outpatients with heart failure and reduced ejection fraction.

AIMS: Heart failure (HF) with reduced left ventricle ejection fraction (LVEF) is an entity with poor prognosis characterized by decompensations. Bioelectrical impedance analysis (BIA) is used to assess volume overload (VO) and may be useful to identify apparently stable HF outpatients at risk of decompensation. The aim of this study is to analyse whether VO assessed by BIA is associated with worsening heart failure (WHF) in stable outpatients with HF and reduced LVEF (HFrEF). METHODS AND RESULTS: This is a prospective single-centre observational study. Consecutive stable HF outpatients with LVEF below 40% underwent BIA, transthoracic echocardiography, blood sampling, and physical examination and were followed up for 3 months. VO was defined as the difference between the measured weight and the dry weight assessed by BIA. Demographic, clinical, anthropometric, echocardiographic, and analytical parameters were recorded. The primary endpoint was WHF, defined by visits to the emergency department for HF or hospitalization for HF. A total of 100 patients were included. The median VO was 0.5 L (interquartile range 0-1.6 L). Eleven patients met the primary endpoint. Univariate binary logistic regression analysis showed that left ventricle filling pressures assessed by E/e', N-terminal pro B-type natriuretic peptide, inferior vena cava dilatation (≥21 mm), signs of congestion, and VO were associated with the primary endpoint. Binary logistic regression multivariate analysis showed that VO was the only independent predictor for the primary endpoint (adjusted OR 2.7; 95% CI 1.30-5.63, P = 0.008). Multivariate Cox regression analysis also showed an adjusted hazard ratio (HR) for VO of 2.03; 95% CI 1.37-3.02, P < 0.001. Receiver-operating characteristic curve analysis showed an area under the curve for VO of 0.88 (95% CI 0.79-0.97, P < 0.001) with an optimal cut-off of 1.2 L. CONCLUSIONS: VO assessed by BIA is independently associated with WHF in stable outpatients with HFrEF at 3 months.

Postoperative Rehabilitation Program for Increasing Muscle Mass in Patients With Hip Fracture: A Retrospective Study.

BACKGROUND: Hip fractures are most likely to occur in older people, and after hip surgery muscle mass and the ability to perform activities of daily living often decline. In this study, we conducted inpatient rehabilitation after surgery for hip fracture and measured changes in muscle mass and physical performance. METHODS: We retrospectively analyzed patients aged 65 years or older who underwent surgery (prosthetic replacement or internal fixation) and inpatient rehabilitation for hip fracture at our hospital between August and December 2020. The training included a joint range of motion exercise, muscle-strengthening exercise, gait training, early mobilization training, and neuromuscular electrical stimulation. We measured the following factors after one and six weeks postoperatively: muscle mass, body weight, fat mass, grip strength, bilateral knee extension strength, ability to walk, and ability to perform activities of daily living. RESULTS: Seventeen patients were included. Median age was 84 years (interquartile range, 72-90). Lower limbs skeletal muscle mass increased (median 4.8 kg to 4.9 kg, p = 0.045), while upper limbs skeletal muscle mass and body weight decreased (median 1.2 kg to 1.1 kg, p = 0.0027), (median 46.8 kg to 45.5 kg, p = 0.0039), respectively. Total skeletal muscle mass and fat mass remained unchanged. Grip strength was maintained, and knee extension muscle strength on the healthy and affected sides increased (healthy side median 10.7 kgf to 13.7 kgf, p = 0.019; affected side median 5.5 kgf to 9.5 kgf, p < 0.001). All patients exhibited improved ability to perform activities of daily living; however, 52.9% of patients regained their pre-injury walking ability. CONCLUSIONS: Our rehabilitation program increased lower limb skeletal muscle mass in patients with hip fractures.

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

BACKGROUND & AIMS: The benefits of physical activity, including exercise and daily and household chores, on the bioimpedance phase angle remain unclear. We aimed to examine the longitudinal association between objectively measured physical activity and bioimpedance phase angle among community-dwelling older adults. METHODS: This community-based cohort study enrolled individuals aged 65 years or older without any disability in the basic activities of daily living. The exposure was physical activity level measured objectively using a tri-axial accelerometer at baseline. The outcome was a whole body phase angle at 50 kHz obtained from a bioelectrical impedance analyzer at a one-year follow-up. The linear regression model was fitted to estimate the continuous associations of physical activity level and phase angle with adjustment of confounders, including age, sex, body mass index, physical performance, and phase angle at baseline. RESULTS: The primary analysis included 229 individuals (mean age = 72.6 years [standard deviation = 4.9], 62.9% females). In the multivariable linear regression model, physical activity level at baseline is associated with a greater phase angle at follow-up (mean difference per 1 increase, 0.53° [95%CI, 0.23-0.83]). Subgroup analysis by sex showed similar trends. Restricted cubic spline analysis indicated a linear association between phase angle at follow-up and physical activity level at baseline (p = 0.66 for non-linearity). CONCLUSIONS: Higher physical activity level was associated with greater phase angle at one-year follow-up in a linear dose-response manner, independent of demographics, physical performance, and phase angle at baseline, in community-dwelling older adults.

Assessing the nutritional status and impact of a series of nutritional interventions on elderly inpatients using bioelectrical impedance analysis: A service evaluation.

BACKGROUND: The aim of the study was to use bioelectrical impedance analysis (BIA) to assess nutritional status of elderly patients admitted to hospital and quantitatively measure the impact of the Cardiff and Vale University Health Board (CAVUHB) model ward. Secondary objectives were to assess the feasibility of using BIA in this patient population and compare nutrition risk screening tools against fat-free mass index (FFMI). METHODS: A prospective, comparative, single-centre, service evaluation of a 'model ward for nutrition and hydration' undertaken in medical and rehabilitation beds in a large UK teaching hospital. RESULTS: A total of 450 BIA measurements were taken using a Bodystat Multiscan 5000 on 162 patients; several patients had repeated measurements during their hospital stay. Patients tolerated the procedure well, but lack of accurate weight, implanted medical devices and tissue viability precluded some participants. CONCLUSIONS: BIA is quick, non-invasive, simple to complete and can elicit huge data about an individual's body composition. In a larger cohort of medical admissions, BIA could assist in identifying the sensitivity and specificity of the nutrition screening tools. The collective benefit of a series of nutritional interventions preserved nutritional status better in this elderly inpatient population than usual models of care. Although results were not statistically significant, there is an opportunity with the new model of care to better support frail patients and prevent deconditioning.

Preoperative body composition measured by bioelectrical impedance analysis can predict pancreatic fistula after pancreatic surgery.

BACKGROUND: Postoperative pancreatic fistula (POPF) remains one of the most severe complications after pancreatic surgery. The methods for predicting pancreatic fistula are limited. We aimed to investigate the predictive value of body composition parameters measured by preoperative bioelectrical impedance analysis (BIA) on the development of POPF. METHODS: A total of 168 consecutive patients undergoing pancreatic surgery from March 2022 to December 2022 at our institution were included in the study and randomly assigned at a 3:2 ratio to the training group and the validation group. All data, including previously reported risk factors for POPF and parameters measured by BIA, were collected. Risk factors were analyzed by univariable and multivariable logistic regression analysis. A prediction model was established to predict the development of POPF based on these parameters. RESULTS: POPF occurred in 41 of 168 (24.4%) patients. In the training group of 101 enrolled patients, visceral fat area (VFA) (odds ratio [OR] = 1.077, P = 0.001) and fat mass index (FMI) (OR = 0.628, P = 0.027) were found to be independently associated with POPF according to multivariable analysis. A prediction model including VFA and FMI was established to predict the development of POPF with an area under the receiver operating characteristic curve (AUC) of 0.753. The efficacy of the prediction model was also confirmed in the internal validation group (AUC 0.785, 95% CI 0.659-0.911). CONCLUSIONS: Preoperative assessment of body fat distribution by BIA can predict the risk of POPF after pancreatic surgery.

Association of Body Water Balance, Nutritional Risk, and Sarcopenia with Outcome in Patients with Acute Ischemic Stroke: A Single-Center Prospective Study.

In the present study, we examined the inter-relationships between body water balance, nutritional risk, sarcopenia, and outcome after acute ischemic stroke (AIS) in patients who were living independently. We defined abnormal body water balance as overhydration, with an extracellular fluid/total body water ratio > 0.390. A geriatric nutritional risk index (GNRI) < 98 was considered low GNRI. Sarcopenia was defined according to the 2019 Asian Working Group for sarcopenia criteria. Poor outcome was defined as a modified Rankin scale (mRS) score ≥ 3 at discharge. Among 111 eligible patients (40 females, median age: 77 years), 43 had a poor prognosis, 31 exhibited overhydration, 25 had low GNRI, and 44 experienced sarcopenia. Patients with poor outcomes had significantly higher National Institutes of Health Stroke Scale (NIHSS) scores, which were significantly more common with overhydration, low GNRI, and sarcopenia (p < 0.001 for all). Concomitant overhydration, low GNRI, and sarcopenia were associated with poorer outcomes. In multivariate analysis, overhydration [odds ratio (OR) 5.504, 95% confidence interval (CI) 1.717-17.648; p = 0.004], age (OR 1.062, 95%CI 1.010-1.117; p = 0.020), and NIHSS score (OR 1.790, 95%CI 1.307-2.451; p < 0.001) were independent prognostic factors for poor outcome. The results indicated that the combination of overhydration, low GNRI, and sarcopenia predict poor outcomes following AIS. Overhydration was particularly associated with poor outcomes.

Usefulness of bioelectrical impedance analysis in multiple sclerosis patients-the interrelationship to the body mass index.

Background: Patients with multiple sclerosis (MS) have many potential factors (disease duration, spasticity, immobilization, or glucocorticoid use) that can deteriorate their nutritional status and impact both the progression and prognosis of the disease. Body mass index (BMI), the most widely used nutritional status assessment tool, has important limitations because it does not provide any data on body composition. Aim: This study aimed to assess the interrelationship between nutritional status assessment by both body mass index (BMI) and body composition using bioelectrical impedance analysis (BIA) and the consistency of diagnosis for underweight/underfat, normal weight/healthy, overweight/overfat, and obesity/obese MS patients. Methods: Anthropometric [BMI and waist-to-height ratio (WHtR)] and body composition (BIA) data were evaluated in 176 patients with MS. Patients were categorized into four nutritional status subgroups (underweight, normal weight, overweight, obese according to BMI, and underfat, healthy, overfat, and obese according to fat mass% by BIA). The median Expanded Disability Status Scale score was 4.5. Patients were then divided according to EDSS score as mild (EDSS 1.0-4.0) or moderate (EDSS 4.5-6.5) disability subgroups. Results: Based on BIA assessment, there was a significantly higher prevalence of overfat than of overweight based on BMI [n = 50 (28.41%) vs. n = 38 (21.59%); p < 0.05]. However, the prevalence of obesity did not differ significantly regardless of the mode of diagnosis and was not significantly lower when assessed using BIA [n = 26 (14.77%) vs. n = 30 (17.05%), respectively]. The overall compatibility rates (CR) of diagnoses made using both BMI and BIA were 75.6, 77.0, and 70.1% for all patients with MS and the mild and moderate subgroups, respectively. The lowest CR was observed in the overweight group. Adiposity significantly underestimated BMI in all subgroups. In the moderate MS subgroup, BMI significantly overcategorized patients with MS as having a normal weight (p < 0.05). Stratification for abdominal obesity (WHtR > 0.5) showed that BMI significantly underestimated the prevalence of MS in overweight and obese vs. overfat and obese patients, as assessed using BIA (60.5 vs. 67%; p < 0.05). Clinical status (EDSS and ΔEDSS) was more closely related to the nutritional status categorized by FAT% assessed using BIA than using BMI cutoff points. However, the relationship was not statistically significant. Conclusion: Using the BMI cutoff point for nutritional status assessment in patients with MS is associated with a significant underestimation of excess fat mass. BIA-based FAT% based on BIA have a better relationship with abdominal obesity and disability status than with BMI in patients with MS. The highest rate of false-negative diagnoses was based on the BMI in patients with MS and moderate disability. Adiposity assessment using BIA appears to be a useful method for proper nutritional status assessment in the patients group.

Factors associated with an improvement in extracellular water-to-total body water ratio in older adults with hip fractures: A decision tree analysis.

BACKGROUND & AIMS: The extracellular water-to-total body water ratio (ECW/TBW) increases with age and after fractures. A high ECW/TBW may hinder improvements in physical function and skeletal muscle mass. However, the effects of ECW/TBW improvement have not been properly investigated. The aim of this study was to investigate the factors associated with ECW/TBW improvement in older adults with hip fractures. METHODS: This retrospective cohort study included 203 patients with hip fractures who were admitted to a convalescent rehabilitation ward. ECW/TBW and skeletal muscle mass index (SMI) were measured using bioelectrical impedance analysis. The patients were classified into two groups: those with an improvement in ECW/TBW (n = 123) and those without an improvement (n = 80). Decision tree analysis was performed to examine the factors associated with ECW/TBW improvement. As a secondary objective, a multiple regression analysis was performed to identify the factors associated with SMI gain. RESULTS: Decision tree analysis identified rehabilitation volume and protein intake as the first and second factors most significantly associated with an improvement in ECW/TBW, respectively. Multiple regression analysis showed that improved ECW/TBW (ß: 0.400, p < 0.001) was significantly associated with SMI gain. CONCLUSIONS: Rehabilitation volume and protein intake are clinically important for improving ECW/TBW in older adults with hip fractures.

Advancing body composition assessment in patients with cancer: First comparisons of traditional versus multicompartment models.

BACKGROUND AND AIMS: Measurement of body composition using computed tomography (CT) scans may be a viable clinical tool for low muscle mass assessment in oncology. However, longitudinal assessments are often infeasible with CT. Clinically accessible body composition technologies can be used to track changes in fat-free mass (FFM) or muscle, though their accuracy may be impacted by cancer-related physiological changes. The purpose of this study was to examine the agreement among accessible body composition method with criterion methods for measures of whole-body FFM measurements and, when possible, muscle mass for the classification of low muscle in patients with cancer. METHODS: Patients with colorectal cancer were recruited to complete measures of whole-body DXA, air displacement plethysmography (ADP), and bioelectrical impedance analysis (BIA). These measures were used alone, or in combination to construct the criterion multicompartment (4C) mode for estimating FFM. Patients also underwent abdominal CT scans as part of routine clinical assessment. Agreement of each method with 4C model was analyzed using mean constant error (CE = criterion - alternative), linear regression including root mean square error (RMSE), Bland-Altman limits of agreement (LoA) and mean percentage difference (MPD). Additionally, appendicular lean soft tissue index (ALSTI) measured by DXA and predicted by CT were compared for the absolute agreement, while the ALSTI values and skeletal muscle index by CT were assessed for agreement on the classification of low muscle mass. RESULTS: Forty-five patients received all measures for the 4C model and 25 had measures within proximity of clinical CT measures. Compared to 4C, DXA outperformed ADP and BIA by showing the strongest overall agreement (CE = 1.96 kg, RMSE = 2.45 kg, MPD = 98.15 ± 2.38%), supporting its use for body composition assessment in patients with cancer. However, CT cutoffs for skeletal muscle index or CT-estimated ALSTI were lower than DXA ALSTI (average 1.0 ± 1.2 kg/m2) with 24.0% to 32.0% of patients having a different low muscle classification by CT when compared to DXA. CONCLUSIONS: Despite discrepancies between clinical body composition assessment and the criterion multicompartment model, DXA demonstrates the strongest agreement with 4C. Disagreement between DXA and CT for low muscle mass classification prompts further evaluation of the measures and cutoffs used with each technique. Multicompartment models may enhance our understanding of body composition variations at the individual patient level and improve the applicability of clinically accessible technologies for classification and monitoring change over time.

Associations between bioelectrical impedance analysis-derived phase angle, protein-energy wasting and all-cause mortality in older patients undergoing haemodialysis.

AIM: Protein-energy wasting (PEW) is a common syndrome in patients undergoing haemodialysis (HD) and is associated with poor prognosis. Bioelectrical impedance analysis (BIA)-derived phase angle (PA) is useful for predicting PEW, but sex and age need to be considered. We aimed to reveal sex-specific cut-off values of PA predicting PEW in HD patients aged ≥65. METHODS: This two-centre retrospective cohort study included patients on HD who underwent BIA. PEW was detected using the International Society of Renal Nutrition and Metabolism (ISRNM) criteria as a reference. The PA was measured using a multifrequency bioimpedance device. Sex-specific cut-off values of PA predicting PEW were detected by receiver-operator characteristic analysis. We investigated the association between PEW determined using sex-specific cut-off values for PA and all-cause mortality. RESULTS: This study included 274 patients undergoing HD, with a median age of 75 (70-80) years, mean PA of 3.8 ± 1.1° and PEW of 43%. Over a median follow-up duration of 1095 (400-1095) days, 111 patients died. Cut-off values of PA predicting PEW were as follows: female, 3.00° (sensitivity, 87.3%; specificity, 77.5%), and male, 3.84° (sensitivity, 77.6%; specificity, 71.4%). The kappa coefficient between sex-specific cut-off values of the PA and ISRNM criteria had a moderate coincidence level of 0.55. PEW detected by PA was independently associated with all-cause mortality (hazard ratio: 2.40; 95% confidence interval: 1.51-3.85; p < .001). CONCLUSIONS: Sex-specific cut-off values for PA in older HD patients may be useful as a screening tool for predicting PEW and mortality.

Development of a bioelectrical impedance analysis-based prediction equation for body composition of rural children aged 4-8 years in Myanmar.

Background: Reliable and accurate estimates of body composition are essential when studying the various health correlates of disease. Bioelectrical impedance analysis (BIA) is an affordable and feasible body composition assessment technique for clinical and field settings. Total body water (TBW) and hence fat-free mass is estimated by predictive regression algorithms using anthropometric measurements plus the resistance index. Aim: The study aimed to develop a BIA prediction equation for TBW in children in Myanmar using the deuterium dilution technique as the reference method. Methods: The study design was cross-sectional in a school setting with convenience sampling of participants. One hundred and two healthy children (57 boys and 45 girls) with aged 4 and 8 years participated; randomly divided into the prediction group (29 boys and 22 girls) and cross-validation group (28 boys and 23 girls). Whole-body impedance, anthropometric and TBW (by D2O dilution) measurements. The prediction equation was cross-validated using a split-group design and compared to published equations for contemporaneous populations. Results: TBW could be predicted by the following equation. TBW = 0.4597 * Weight (kg) + 0.1564 * Impedance index + 0.6075 (R2 = 0.891, P < 0.0001) with a correlation coefficient of 0.942 and limits of agreement of 0.98 kg TBW on cross-validation. Conclusions: This equation can be used to predict body composition in young (aged 4-8 years) children in Myanmar but because the age range of the participants in the present study was relatively narrow, more research in different age groups is required to establish its broader applicability.

Validity and agreement between dual-energy X-ray absorptiometry, anthropometry and bioelectrical impedance in the estimation of fat mass in young adults.

Introduction: Assessment of fat mass has historically employed various methods like Dual-energy X-ray Absorptiometry (DXA), and bioelectrical impedance (BIA), and anthropometry with its set of formulas. However, doubts persist regarding their validity and interchangeability to evaluate fat mass. This research aimed to determine the validity of anthropometry, and BIA in estimating fat mass Vs DXA, considering the influence of sex and hydration status. Methods: A descriptive, cross-sectional study included 265 young adults (161 males and 104 females), assessed through DXA, BIA in a standing position, and anthropometry. A fat mass estimation formula with DXA, a fat mass estimation formula with BIA and 10 fat mass estimation formulas with anthropometry were calculated. Results: Significant differences were found across DXA, BIA and anthropometry in both kilograms and percentages for the overall sample (p<0.001), and when the covariable sex was included (p<0.001), with no significant effect of hydration status (p=0.332-0.527). Bonferroni-adjusted analyses revealed significant differences from DXA with anthropometry and BIA in most cases for the overall sample (p<0.001), as well as when stratified by sex (p<0.001-0.016). Lin's coefficient indicated poor agreement between most of the formulas and methods both in percentage and kilograms of fat mass (CCC=0.135-0.892). In the Bland-Altman analysis, using the DXA fat mass values as a reference, lack of agreement was found in the general sample (p<0.001-0.007), except for Carter's formula in kilograms (p=0.136) and percentage (p=0.929) and Forsyth for percentage (p=0.365). When separating the sample by sex, lack of agreement was found in males for all methods when compared with both percentage and kilograms calculated by DXA (p<0.001). In the female sample, all methods and formulas showed lack of agreement (p<0.001-0.020), except for Evans's in percentage (p=0.058). Conclusion: The formulas for fat mass assessment with anthropometry and BIA may not be valid with respect to the values reported with DXA, with the exception of Carter's anthropometry formula for general sample and Evans's anthropometry formula for female sample. BIA could also be an alternative if what is needed is to assess fat mass in women as a group.

Body Fat Distribution and Left Atrial Reverse Remodeling After Catheter Ablation for Atrial Fibrillation.

Background: Emerging evidence suggests a pathophysiological link between obesity and atrial fibrillation (AF). However, the contribution of body fat distribution to left atrial (LA) remodeling and its reversibility remain unclear in nonobese AF patients. Objectives: The purpose of this study was to investigate the association of body fat distribution with LA size and reverse remodeling (LARR). Methods: In total, 116 nonobese patients with AF (88 men, age 63 ± 11 years) who underwent first catheter ablation (CA) were included. Body fat distribution was assessed with bioelectrical impedance, and body fat percentage (BF%) and central fat percentage (CF%) were calculated. Patients were categorized by body size metrics (body mass index [BMI] and waist-to-hip [W/H] ratio) and fat parameters (BF% and CF%). Echocardiography was performed before and 6 months after CA. Multivariable logistic regression was used to examine the association between the 4 metrics (ie, BMI, W/H ratio, BF%, and CF%) and a lack of LARR (<15% reduction or increase in the LA volume index). Results: Body size metrics and adiposity measures were not independently associated with baseline LA size. Six months after CA, the higher W/H ratio and CF% groups exhibited persistent LA enlargement compared to their counterparts (both P < 0.01). In the multivariable analysis, W/H ratio and CF% were associated with a lack of LARR (adjusted ORs of 3.86 and 2.81 per 0.10 and 10% increase, respectively, both P < 0.01). The combined assessment of CF% with W/H ratio provided complementary risk stratification for persistent LA enlargement. Conclusions: Central adiposity was associated with a lack of LARR after CA, highlighting the importance of assessing body fat distribution even in nonobese patients.

Evaluation of Energy Balance Estimated From Total Energy Expenditure and Body Composition Changes in Junior Sumo Wrestlers: An Observational Study Over Six Months.

Background Sumo is a sport that requires wrestlers to develop their physique from childhood for athletic advantage. However, the energy expenditure and energy balance required for the growth of junior Sumo wrestlers remain unclear. This study aimed to determine the energy balance of junior Sumo wrestlers over six months using doubly labeled water (DLW) and bioelectrical impedance analysis (BIA). Methodology A total of 12 male Sumo wrestlers were affiliated with a local Sumo club (average age = 15 ± 1 years). The total energy expenditure (TEE) was measured using DLW, whereas body composition was evaluated using BIA. Daily physical activity was quantified using a tri-accelerometer (Active style Pro HJA-750C). Results The TEE was 4,194 ± 734 kcal/day, while daily physical activity without training was 786 ± 50 minutes. Within six months, the body weight increased by 2.0 ± 3.2 kg, fat-free mass (FFM) was augmented by 2.1 kg, while fat mass did not change significantly. The surplus energy accumulated was 5.6 ± 213 kcal/day. Conclusions The excess energy of junior Sumo wrestlers predominantly increases their FFM. To increase their physical prowess, wrestlers adhere to a lifestyle characterized by high-intensity training and attenuated daily physical activity.

Water temperature affects somatic growth, body condition and oxygen and carbon otolith isotopes of stout whiting (Sillago robusta).

Ocean warming will continue to affect the growth, body condition and geographic distributions of marine fishes and understanding these effects is an urgent challenge for fisheries research and management. Determining how temperature is recorded in fish otolith carbonate, provides an additional chronological tool to investigate thermal histories, preferences and patterns of movement throughout an individual's life history. The influence of three water temperature treatments (22°C, 25°C, and 28°C) on hatchery-reared juvenile stout whiting, Sillago robusta, was tested using a controlled outdoor mesocosm system. Fish were measured for change in length and weight, and body condition was determined using bioelectrical impedance analysis. Sagittal otoliths were analysed for stable oxygen (δ18Ootolith) and carbon (δ13Cotolith) isotopes via isotope ratio mass spectrometry. Whiting kept at 22°C were significantly smaller and had diminished body condition compared to fish in 25°C and 28°C, which did not significantly differ from each other. The δ18O otolith values of stout whiting demonstrated a negative temperature-dependent fractionation relationship which was similar in slope but had a different intercept to the relationships reported for inorganic aragonite and other marine fish species. The δ13C otolith values also showed a negative relationship with water temperature, and the calculated proportion of metabolic carbon M in otoliths differed between fish reared in the coolest (22°C) and warmest (28°C) temperature treatments. Overall, the results suggest that stout whiting may have reached an upper growth threshold between 25°C and 28°C, and that growth and body condition may be optimised during warmer seasons and toward the northerly regions of their distribution. Otolith oxygen thermometry shows promise as a natural tracer of thermal life history, and species-specific fractionation equations should be utilised when possible to prevent errors in temperature reconstructions of wild-caught fish.

Normative values for body composition in 22,191 healthy Norwegian adults 20-99 years: The HUNT4 study.

BACKGROUND: Body mass, body mass index (BMI), and body composition components are essential for health and longevity. Considering the influence of demographic factors on body composition, there is a need for tailored reference values based on age-, sex-, and geography. We aimed to construct a comprehensive reference material on body composition in healthy Norwegian adults. METHODS: In this cross-sectional study, we estimated age- and sex-specific reference values for body-, fat-, and muscle mass variables using multi-frequency bioelectrial impedance analysis (such as body fat percentage, skeletal muscle mass and visceral fat area) in 22,191 healthy adults aged 20-99 years participating in the Trøndelag Health Study 4 (HUNT4). We calculated the fat mass and skeletal muscle mass index as the total fat and muscle mass relative to height squared and used general linear models to explore the associations between physical activity (PA), BMI, and age. RESULTS: With a BMI (kg/m2) of 25.4 (SD 5.1) and 26.0 (4.5) for women and men, respectively, the youngest age group (20-39 yrs) had a lower BMI compared to their counterparts aged 40-59 years (26.3 [4.5] and 27.5 [3.8]) and ≥ 60 years (25.7 [4.1] and 26.5 [3.4]), respectively. Those aged 20-39 years also had the lowest values for the different body fat variables measured. Fat mass index (kg/m2) was 8.41 (4.00) and 5.81 (3.29) for women and men aged 20-39 years, respectively, compared to 9.25 (3.21) and 6.86 (2.46) for those aged ≥60 years. The oldest age group had the lowest values for the various muscle mass variables; women and men aged 60+ years had a skeletal muscle mass index (kg/m2) of 8.91 (0.85) and 10.96 (1.00), respectively. Corresponding values for those aged 20-39 years were 9.33 (0.97) and 11.49 (1.15). For all age groups and both sexes, regular physical activity was associated with lower levels of fat mass, whereas the association between muscle mass and PAwas less conclusive. When using body fat percentage as an obesity measure, we observed a much higher obesity prevalence (41.2%) in the study population compared to BMI (17.3%). CONCLUSIONS: Our study offers a comprehensive reference for body composition among healthy adults in Norway, aiding the identification of abnormal fat and muscle mass values across age groups. We also highlight that BMI often misclassifies individuals with adiposity levels in the overweight or obese category as lean. Therefore, incorporating body composition when defining obesity could enable early intervention to prevent cardiometabolic diseases.