Accuracy of eight-polar bioelectrical impedance analysis for the assessment of total and appendicular body composition in peritoneal dialysis patients

Estimation of fluid status using three multifrequency bioimpedance methods in hemodialysis patients

INTRODUCTION

Segmental eight-point bioimpedance has been increasingly used in practice. However, whether changes in bioimpedance analysis components before and after hemodialysis (HD) using this technique in a standing position is comparable to traditional whole-body wrist-to-ankle method is still unclear. We aimed to investigate the differences between two eight-point devices (InBody 770 and Seca mBCA 514) and one wrist-to-ankle (Hydra 4200) in HD patients and healthy subjects in a standing position.

METHODS

Thirteen HD patients were studied pre- and post-HD, and 12 healthy subjects once. Four measurements were performed in the following order: InBody; Seca; Hydra; and InBody again. Electrical equivalent models by each bioimpedance method and the fluid volume estimates by each device were also compared.

FINDINGS

Overall, total body water (TBW) was not different between the three devices, but InBody showed lower extracellular water (ECW) and higher intracellular water (ICW) compared to the other two devices. When intradialytic weight loss was used as a surrogate for changes in ECW (∆ECW) and changes in TBW (∆TBW), ∆ECW was underestimated by Hydra (-0.79 ± 0.89 L, p < 0.01), InBody (-1.44 ± 0.65 L, p < 0.0001), and Seca (-0.32 ± 1.34, n.s.). ∆TBW was underestimated by Hydra (-1.14 ± 2.81 L, n.s.) and InBody (-0.52 ± 0.85 L, p < 0.05) but overestimated by Seca (+0.93 ± 3.55 L, n.s.).

DISCUSSION

Although segmental eight-point bioimpedance techniques provided comparable TBW measurements not affected by standing over a period of 10-15 min, the ECW/TBW ratio appeared to be significantly lower in InBody compared with Seca and Hydra. Results from our study showed lack of agreement between different bioimpedance devices; direct comparison of ECW, ICW, and ECW/TBW between different devices should be avoided and clinicians should use the same device to track the fluid status in their HD population in a longitudinal direction.

Electrical Impedance of Upper Limb Enables Robust Wearable Identity Recognition against Variation in Finger Placement and Environmental Factors

Most biometric authentication technologies commercialized in various fields mainly rely on acquired images of structural information, such as fingerprints, irises, and faces. However, bio-recognition techniques using these existing physical features are always at risk of template forgery threats, such as fake fingerprints. Due to the risk of theft and duplication, studies have recently been attempted using the internal structure and biological characteristics of the human body, including our previous works on the ratiometric biological impedance feature. However, one may still question its accuracy in real-life use due to the artifacts from sensing position variability and electrode-skin interfacing noise. Moreover, since the finger possesses more severe thermoregulatory vasomotion and large variability in the tissue properties than the core of the body, it is necessary to mitigate the harsh changes occurring at the peripheral extremities of the human body. To address these challenges, we propose a biometric authentication method through robust feature extraction from the upper-limb impedance acquired based on a portable wearable device. In this work, we show that the upper limb impedance features obtained from wearable devices are robust against undesirable factors such as finger placement deviations and day-to-day physiological changes, along with ratiometric impedance features. Overall, our upper-limb impedance-based analysis in a dataset of 1627 measurement from 33 subjects lowered the classification error rate from 22.38% to 4.3% (by a factor of 5), and further down to 2.4% (by a factor of 9) when combined with the ratiometric features.

Impact of extracellular-to-intracellular fluid volume ratio on albuminuria in patients with type 2 diabetes: A cross-sectional and longitudinal cohort study

AIMS/INTRODUCTION

Body fluid volume imbalance is common in patients with kidney failure, and is associated with all-cause mortality. This study aimed to investigate the association between fluid volume imbalance and albuminuria in patients with type 2 diabetes mellitus without kidney failure.

MATERIALS AND METHODS

Using data from one cohort study, a baseline cross-sectional study of 432 participants and a longitudinal cohort study of 368 participants who could follow up was carried out. Body fluid imbalance was determined by measuring the extracellular water (ECW)-to-intracellular water (ICW) ratio (ECW/ICW) using bioelectrical impedance analysis. A change in the urinary albumin-to-creatinine ratio (ACR) was defined as the ratio of urinary ACR at follow up to that at baseline. The ECW/ICW ratio was compared with the level of albuminuria.

RESULTS

In this cross-sectional study, the ECW/ICW ratio increased with the level of albuminuria. There was an association between the ECW/ICW ratio and logarithms of urinary ACR after adjusting for covariates (β = 0.205, P < 0.001). Furthermore, the ECW/ICW ratio was associated with a change in the urinary ACR after adjusting for covariates (β = 0.176, P = 0.004) in this longitudinal study. According to the receiver operating characteristic curve, the optimal cut-off point of the ECW/ICW ratio for incident macroalbuminuria, defined as ACR >300 mg/gCr, was 0.648 (area under the curve 0.78, 95% confidence interval 0.58-0.90).

CONCLUSIONS

The ECW/ICW ratio is independently associated with the level of albuminuria in patients with type 2 diabetes mellitus without kidney failure. This reinforces the importance of monitoring fluid balance in patients with type 2 diabetes mellitus.

Validation of the SARC-F for Assessing Sarcopenia in Patients on Peritoneal Dialysis

OBJECTIVE

Proper screening or diagnosis of sarcopenia (SP) is important to obtain favorable outcomes in patients on peritoneal dialysis (PD). Previous studies have shown that the SARC-F is associated with various parameters of SP in elderly populations. In this study, we aimed to validate the SARC-F questionnaire for predicting SP in patients on PD.

METHODS

This cross-sectional study was conducted at a tertiary medical center. We identified all patients prevalent on PD patients (n = 127). A version of the original SARC-F was used to assess the questionnaire. Patients with a total score of ≥4 points were defined as the high group and those with <4 points were defined as the normal group. The hand grip strength and appendicular skeletal muscle mass index were measured in all patients. SP was defined as previously reported.

RESULTS

Of the 127 total patients, 29 (22.8%, high group) had an SARC-F score of ≥4. The sensitivity and specificity of the SARC-F for predicting SP were 70.0% and 81.2%, respectively. The negative predictive and positive predictive values were 96.9% and 24.1%, respectively. The area under curve of the SARC-F score for SP was 0.791 (0.709-0.858, P < .001). The hand grip strength of the normal and high groups was 26.4 ± 8.5 and 19.5 ± 6.8 kg, respectively (P < .001). The appendicular skeletal muscle mass index in the normal and high groups was 7.6 ± 1.3 and 7.2 ± 1.8 kg/m², respectively (P = .152). An increase in the SARC-F score as a continuous variable or classification into the high group as a categorical variable was associated with a higher odds ratio for SP in univariate and multivariate analyses.

CONCLUSION

The SARC-F has a high negative predictive value and a high specificity for predicting SP in patients on PD.

Evaluation of oxygen uptake adjusted by skeletal muscle mass in cardiovascular disease patients with type 2 diabetes

[Purpose] We aimed to evaluate oxygen uptake adjusted by total skeletal muscle mass in patients with cardiovascular disease with or without type 2 diabetes mellitus. [Participants and Methods] The participants included 54 males ≥50 years of age without heart failure who underwent cardiopulmonary exercise testing during cardiac rehabilitation. We divided the participants into two groups: patients with type 2 diabetes mellitus (DM group) and patients without type 2 diabetes mellitus (NDM group). [Results] We found no significant differences in age, weight, fat mass, or skeletal muscle mass between the groups. There were also no differences in cardiac function, body composition, and heart rate response. The DM group showed significantly lower peak oxygen uptake values adjusted by skeletal muscle mass, despite the absence of significant differences in skeletal muscle mass. A significant positive correlation was found between peak oxygen uptake and age, weight, and skeletal muscle mass. Stepwise regression analysis revealed that age, skeletal muscle mass, and medical history of diabetes were independent predictors of absolute peak oxygen uptake. [Conclusion] Peak oxygen uptake adjusted by skeletal muscle mass in patients with cardiovascular disease and type 2 diabetes mellitus is lower than that in those without type 2 diabetes mellitus.

Development and validation of a multifrequency bioimpedance spectroscopy equation to predict appendicular skeletal muscle mass in hemodialysis patients

BACKGROUND & AIMS

The Body Composition Monitor (BCM), a multifrequency bioimpedance spectroscopy device, has been widely used to assess body composition in hemodialysis patients because its measurement is not affected by overhydration commonly seen in chronic kidney disease. We aimed to develop and validate an equation for obtaining appendicular skeletal muscle mass (ASM) from BCM taking dual-energy X-ray absorptiometry (DXA) as the reference among hemodialysis patients.

METHODS

A total of 322 consecutive body composition measurements with BCM and DXA in 263 hemodialysis patients were randomly divided at a ratio of 2:1 into development and validation groups. Stepwise multiple regression modeling was applied to develop the ASM prediction equation. We evaluated the model as a diagnostic tool for sarcopenia using cutoffs of ASM defined by the Asian Working Group for Sarcopenia (AWGS). We further explored the association between ASM predicted by the BCM equation and all-cause mortality in two independent cohorts: one with 326 stage 3-5 CKD patients and one with 629 hemodialysis patients.

RESULTS

BCM yielded the following equation: ASM (kg) = -1.838 + 0.395 × total body water (L) + 0.105 × body weight (kg) + 1.231 × male sex - 0.026 × age (years) (R² = 0.914, standard error of estimate = 1.35 kg). In the validation group, Bland-Altman reliability analysis showed no significant bias of 0.098 kg and limits of agreement ±2.440 kg. Using the AWGS criteria, the model was found to have a sensitivity of 94.1%, a specificity of 98.8%, a positive predictive value of 84.2%, and a negative predictive value of 99.6% for the diagnosis of sarcopenia. Low ASM predicted by the BCM equation was associated with significantly worse overall survival among CKD patients but not hemodialysis patients.

CONCLUSIONS

The new BCM equation provides a feasible and valid option for assessing ASM in hemodialysis patients.

The Association between Serum Uric Acid and Appendicular Skeletal Muscle Mass and the Effect of Their Interaction on Mortality in Patients on Peritoneal Dialysis

BACKGROUND

Serum uric acid (SUA) has been revealed to be positively associated with the body composition parameters in hemodialysis patients, but few studies have investigated that in patients on peritoneal dialysis (PD). The aim of this study was to identify the relationship between SUA and appendicular skeletal muscle mass (ASM) and the effect of their interaction on mortality in PD patients.

METHODS

This was a single-center retrospective cohort study. Patients who underwent multifrequency bioelectrical impedance analysis between January 1, 2013, and December 31, 2016, and had data on SUA values were enrolled. All patients were followed up until December 31, 2019.

RESULTS

In total, 802 prevalent PD patients (57.9% male), with mean age of 46.2 ± 14.2 years were enrolled. The average SUA and ASM were 6.8 ± 1.3 mg/dL and 21.2 ± 4.9 kg. According to multiple linear regression models, SUA was positively associated with relative ASM in middle-aged and older PD patients (standardized coefficients [β] 0.117; 95% confidence interval [CI] 0.027, 0.200; p = 0.010). Further sex-stratified analysis showed that the association existed only in males (β 0.161; 95% CI 0.017, 0.227; p = 0.023). Moreover, the presence of hyperuricemia was found to predict lower risk of all-cause mortality (hazard ratio [HR] 0.514, 95% CI 0.272, 0.970; p = 0.040) only in patients with lower relative ASM. And, the adjusted HR of every 1 mg/dL elevated SUA level was 0.770 (95% CI 0.609, 0.972; p = 0.028) for all-cause mortality in the lower relative ASM subgroup.

CONCLUSIONS

There exists a positive association between the SUA and ASM, and the ASM significantly affected the association between SUA and all-cause PD mortality.

High Levels of Physical Activity May Promote a Reduction in Bone Mineral Density in Peritoneal Dialysis

Background and objectives: Peritoneal dialysis (PD) patients are expected to present lower levels of physical activity, unhealthy changes at the body composition level, and low levels of strength. Firstly, this study aimed to report the sex differences in physical activity, body composition and muscle strength and the relations among these variables. Secondly, we analyze the relationship between physical activity and biochemical parameters. Materials and Methods: Thirty-four patients (13 women and 21 men) participated in this study. Body composition was assessed by bioimpedance and dual-energy X-ray absorptiometry (DXA), and maximum isokinetic unilateral strength, analytical parameters and physical activity levels were evaluated. Results: The men showed higher values for weight, height, lean body mass, bone mineral content, bone mineral density (BMD) and total body water, while women showed higher values for the percentage of fat mass and hydration of lean body mass (p < 0.05). No differences between the sexes were found in different levels of physical activity; however, males registered significantly higher values for isokinetic strength variables except for knee extensor strength. BMD was positively related to sedentary activity and negatively related to moderate and vigorous activity (r = 0.383 and r = -0.404, respectively). Light physical activity was negatively correlated with albumin (r = -0.393) and total protein (r = -0.410) levels, while moderate/vigorous activity was positively correlated with urea distribution volume (r = 0.446) and creatinine clearance (r = 0.359) and negatively correlated with the triglyceride level (r = -0.455). Conclusions: PD patients with higher levels of physical activity present better results in terms of body composition and biochemical parameters. Additional studies should be conducted to clarify the relation between physical activity level and BMD.

Prenatal exposure to di-(2-ethylhexyl) phthalate and decreased skeletal muscle mass in 6-year-old children: A prospective birth cohort study

BACKGROUND/AIM

Phthalate is a well-known endocrine-disrupting chemical that has anti-androgenic effects. Although there are several studies on the relationship between body composition and phthalate, studies that investigated the effects of phthalate on skeletal muscle during childhood are lacking.

METHODS

We analyzed data from 481 mother-and-child pairs enrolled in the Environment and Development of Children cohort in South Korea. We examined the association between phthalate metabolites (mono [2-ethyl-5-hydroxyhexyl] phthalate [MEHHP], mono [2-ethyl-5-oxohexyl] phthalate [MEOHP], molar sum of MEHHP and MEOHP [Σ DEHP], and mono-n-butyl phthalate [MnBP]) in prenatal maternal urine and children's urine at the age of 6, and body composition indices (body mass index [BMI] z-score, percentage of fat mass, fat mass index, percentage of skeletal muscle, and the skeletal muscle index [SMI]) measured when the child was 6 years using a bioelectrical impedance analyzer.

RESULTS

A 2-fold increase in Σ DEHP and MnBP in the prenatal maternal urine was significantly associated with a -0.07 unit (95% CI: -0.11, -0.03) and -0.09 unit (95% CI: -0.14, -0.03) change in SMI, respectively, in 6-year old girls alone. BMI z-score was also negatively associated with a 2-fold increase in MEHHP and MnBP in prenatal maternal urine as -0.11 unit (95% CI: -0.22, -0.01) and -0.15 unit (95% CI: -0.28, -0.02) change, respectively, only among girls. Among boys, phthalate metabolites in the prenatal and children's urine were not significantly associated with any body composition indices.

CONCLUSIONS

Our longitudinal study shows that high levels of prenatal exposure to phthalates are significantly associated with decreased SMI among girls. We can postulate that anti-androgenic effects of phthalates during pregnancy may affect girl offspring's muscle growth.

Equation models developed with bioelectric impedance analysis tools to assess muscle mass: A systematic review

BACKGROUND & AIMS

This systematic review aims to systematically assess and summarize the equation models developed to estimate muscle mass with bioelectric impedance analysis (BIA) instruments against a reference instrument (DXA, MRI, CT-scan, Ultrasonography), in order to help researchers and clinicians choose the most adapted equation, depending on the device and the population in question.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was followed. Medline (via Ovid) and Scopus were searched in January 2019 for observational (transversal, longitudinal, retrospective) studies developing an equation prediction model to validate BIA against another reference method for the assessment of muscle mass. Study selection and data extraction was performed independently by two researchers. Methodological quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool.

RESULTS

25 studies matched the inclusion criteria and were included in the present systematic review. Among them, 10 studies proposed an equation for subjects aged 65 years and older, 9 for adults, 4 for infants and 2 did not report the age of the population. A large heterogeneity was observed regarding the brand and type of BIA as well as the administration protocol (mode, frequency, number of electrodes, administration position and empty bladder/stomach or not). Most of the studies used DXA as the reference instrument, except 4 that used MRI. In each of the included papers authors provided, through simple or multiple regression, a predictive equation for muscle mass. BIA resistance index, sex, weight, age, BIA reactance and height were most frequently included as predictive variables. The majority of the equations developed explained more than 80% of the variance between both instruments. Out of the 25 equations available, only 9 were also validated in another population within the same paper.

CONCLUSION

This systematic review of the literature offers clinicians and researchers the opportunity to verify the existence of a prediction equation when using a BIA device for estimating muscle mass. This will help them to obtain a valid estimation of muscle mass in a specific population and with a specific instrument. If the equation exists and has been validated by a study free of high risk of bias, it's use is recommended because the development of a new equation in the same context seems redundant and undesirable. If a validation has not been carried out for a specific brand of BIA, reference method or population, we recommend the development and cross-validation of a new equation.

Assessment of Skin Properties in Chronic Lymphedema: Measurement of Skin Stiffness, Percentage Water Content, and Transepidermal Water Loss

Background: Lymphedema (LE) is a chronic progressive protein-rich edema of the soft tissues. Measurement of extracellular fluid of the affected limbs is widely used in detecting LE; however, quantification of the skin alterations and early tissue changes in LE lacks approaches. Methods and Results: Ninety-one patients with LE were assessed. Measurement of transepidermal water loss (TEWL), skin stiffness (SF), and percentage water content (PWC) was assessed on five predetermined skin sites. The value of TEWL, SF, and PWC increased significantly in lymphedematous skin compare with controls, indicating damaged function and texture of the affected skin. Both PWC ratio and SF ratio strongly correlated with LE stage. High correlations were found among instruments assessing tissue fluid. Conclusions: Assessment of the skin parameters has contributed new information about the functional and structural alterations in chronic lymphedematous skin. Quantification of skin properties changes could be a valuable supplement to diagnosis and evaluation of chronic LE.

Ratiometric Impedance Sensing of Fingers for Robust Identity Authentication

We present a novel biometric authentication system enabled by ratiometric analysis of impedance of fingers. In comparison to the traditional biometrics that relies on acquired images of structural information of physiological characteristics, our biological impedance approach not only eliminates any practical means of making fake copies of the relevant physiological traits but also provides reliable features of biometrics using the ratiometric impedance of fingers. This study shows that the ratiometric features of the impedance of fingers in 10 different pairs using 5 electrodes at the fingertips can reduce the variation due to undesirable factors such as temperature and day-to-day physiological variations. By calculating the ratio of impedances, the difference between individual subjects was amplified and the spectral patterns were diversified. Overall, our ratiometric analysis of impedance improved the classification accuracy of 41 subjects and reduced the error rate of classification from 29.32% to 5.86% (by a factor of 5).

Body Fat Mass and Risk of Cerebrovascular Lesions: The PRESENT (Prevention of Stroke and Dementia) Project

Obesity is known to increase the risk of stroke. It is unclear whether high absolute fat mass (FM) increases the risk of stroke independently. We studied the correlation between FM and silent brain infarction/white matter change (SI/WMC) using brain computed tomography. We selected subjects from the local government health promotion project. We randomly selected a target population that had never been diagnosed with stroke or dementia. FM was measured by bioelectrical impedance analysis (BIA). We divided the subjects into three groups according to the FM (gender-specific tertiles [GTx]). Seven hundred and twenty-two subjects (321 men) between 50 and 75 years of age were recruited. The overall odds ratio (OR) of SI/WMC was 2.23 (95% confidence interval (CI), 1.34-3.71; p = 0.002) times higher in the 37th to 100th percentiles (GT3) than in the first to 32nd percentiles (GT1). When men and women were separated, the OR of GT3 was 1.35 (CI, 0.62-2.94; p = 0.45) in men and 3.2 (CI, 1.60-6.40; p = 0.001) in women. The findings were not found to be statistically significant after adjusting for the well-known stroke risk factors. When the subjects were divided into a high FM (HFMG, GT3) and low FM group (LFMG, GT1 + GT2), the HFMG showed an increased OR of SI/WMC in women. Similar results were seen after adjusted (overall: OR, 1.38; CI, 0.85-2.25, p = 0.198; men: OR, 0.93; CI, 0.422-2.051; p = 0.86; women: OR, 2.02; CI, 1.06-3.86; p = 0.03). The findings suggest that high FM may be an independent risk factor for ischemic stroke among adults free from stroke and dementia, especially in women.

Effects of FABP2 Ala54Thr gene polymorphism on obesity and metabolic syndrome in middle-aged Korean women with abdominal obesity

OBJECTIVES

Asians (including Chinese, Japanese and Koreans), who generally have a relatively smaller body size and a lower mean body mass index (BMI), have a relatively higher risk of developing android-type obesity than westerners. Substitution of alanine for threonine (Ala54Thr) on the FABP2 gene (rs 1799883) is related to insulin resistance and obesity. However, few studies have examined this substitution in Koreans, and the number of Korean subjects in those studies is limited. For this reason, we investigated the differences between the FABP2 Ala54Thr polymorphism and obesity, hemodynamic variables, blood lipid profile results, and insulin resistance among middle-aged Korean women with abdominal obesity.

METHODS

We studied 243 middle-aged community-dwelling Korean women with abdominal obesity from Gyeonggi Province, Republic of Korea, who had no history of taking chronic medications. We examined each subject (n = 243) for the presence of FABP2 Ala54Thr polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Subjects were also examined for obesity hemodynamic variables (n = 243), lipid profiles (n = 142), and insulin resistance (n = 142).

RESULTS

Of the 243 subjects, 117 had AA ("normal") homozygotic genotype, 100 had AT heterozygotic genotype, and 26 had TT homozygotic genotype for the FABP2 Ala54Thr polymorphism. The AT heterozygotic individuals had a significantly higher mean waist-to-hip ratio, abdominal fat area, and visceral fat area than individuals with other genotypes. TT homozygotic individuals had higher mean triglyceride and fasting glucose levels than individuals with other genotypes.

CONCLUSIONS

The results of this study show that the FABP2 Ala54Thr polymorphism was associated with central obesity and obesity-related metabolic syndrome among middle-aged Korean women.

Viscus fat area contributes to the Framingham 10-year general cardiovascular disease risk in patients with type 2 diabetes mellitus

OBJECTIVE

To explore the correlation of the viscus fat area (VFA) with the Framingham 10-year general cardiovascular disease risk in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 202 patients with T2DM were divided into two groups based on VFA (a VFA ≥ 100 cm² group and a VFA < 100 cm² group), or four groups based on sex and age (a middle-aged male group, an elderly male group, a middle-aged female group, and an elderly female group). The correlation between the Framingham 10-year general cardiovascular disease risk and body fat indexes was analyzed.

RESULTS

Patients in the VFA ≥ 100 cm² group had higher body fat indexes and Framingham Risk Scores (FRSs) and lower levels of high density lipoprotein-cholesterol (HDL-C) when compared to the VFA < 100 cm² group (P < 0.05). Female patients had higher body fat mass (BFM) and body fat percentage (BFP) levels and a lower VFA when compared to male patients. The VFA was significantly higher in the elderly than in the middle-aged patients. The waist hip fat ratio (WHFR) was significantly higher in elderly females than in elderly males (P < 0.05). Elderly females had the highest FRS of all patients. Multiple stepwise regression analysis revealed the VFA as a contributor to the Framingham 10-year general cardiovascular disease risk after statistical correction for other multiple factors affecting cardiovascular disease risk.

CONCLUSION

The VFA is an independent factor that contributes to the Framingham 10-year general cardiovascular disease risk in patients with T2DM.

Amino Acid-Based Metabolic Panel Provides Robust Prognostic Value Additive to B-Natriuretic Peptide and Traditional Risk Factors in Heart Failure

Metabolic disturbances represent functional perturbation in peripheral tissues and predict outcomes in patients with heart failure (HF). This study developed an amino acid-based metabolic panel and sought to see whether this panel could add diagnostic and prognostic value to currently used B-type natriuretic peptide (BNP) measurements. Mass spectrometry and ultra-performance liquid chromatography were performed on 1288 participants, including 129 normal controls and 712 patients at HF stages A to D in the initial cohort and 447 stage C patients in the validation cohort. Patients were followed up for composite events (death/HF-related rehospitalization). Histidine, ornithine, and phenylalanine were 3 metabolites found strongly significant to identify patients at stage C and were adopted to develop the HOP panel. Compared to BNP, HOP had better value in discriminating the patients at different stages, especially in elderly patients and those with atrial fibrillation, high body mass index, or kidney dysfunction. HOP was correlated with the distance of 6 min walking distance better than BNP. For prognosis, HOP predicted composite events in patients at stages C and D, independent of log (BNP), age, sex, left ventricular ejection fraction, New York Heart Association functional class, HF stage, diabetes mellitus, chronic kidney disease, hypertension, hemoglobin, and albumin. Higher BNP (≥750 pg/mL) along with higher HOP (≥14) robustly predicted lower event-free survival compared to all others [hazard ratio = 3.15 (2.23-4.46), p < 0.001]. The prognostic value of HOP was confirmed in the validation cohort. In conclusion, aiming for clinical applications, this study proved that the HOP panel provides diagnostic and prognostic value additive to BNP and traditional risk factors.

Gender-specific associations of skeletal muscle mass and arterial stiffness among peritoneal dialysis patients

Decreased skeletal muscle has been identified as a relevant factor for arterial stiffness but has not been thoroughly investigated in peritoneal dialysis (PD) patients. The aim of this study was to investigate the relationship between skeletal muscle and arterial stiffness in PD patients. A cross-sectional study of 658 prevalent PD patients with a mean brachial-ankle pulse wave velocity (baPWV) of 1714 (±501) cm/s and mean skeletal muscle mass of 26.6 (±5.4) kg was performed. Skeletal muscle mass level was significantly higher in males than in females. When examining skeletal muscle mass as a continuous variable, skeletal muscle mass was significantly associated with baPWV in fully adjusted linear regression models in total patients [standardized coefficients (β), −0.181; 95% confidence interval (95% CI), −0.276 to −0.056; P = 0.003] or female patients (β, −0.119; 95% CI, −0.350 to −0.015; P = 0.03) but not in male patients (β, −0.117; 95% CI, −0.300 to 0.011; P = 0.07). Furthermore, in females, a significant association between the middle or highest tertile of skeletal muscle mass and baPWV was found in fully adjusted models (β, −0.123; 95% CI, −0.204 to −0.008; P = 0.03; β, −0.140; 95% CI, −0.228 to −0.016; P = 0.02, respectively). In conclusion, decreased skeletal muscle mass was independently associated with increased baPWV in PD patients, and this association was significant in females but not in males.

Effects of procedure, upright equilibrium time, sex and BMI on the precision of body fluid measurements using bioelectrical impedance analysis

BACKGROUND/OBJECTIVES

Extensive work has addressed the validity of bioimpedance (BIA) measurements and the effect of posture on fluid homeostasis. However, limited research has investigated effects of subject preparation. This study aimed to determine the precision of total body water (TBW) and extracellular water (ECW) measurements using a stand-on multifrequency BIA (MFBIA seca mBCA 514/515), in three pre-test procedures: supine, sitting, and following walking, with specific reference to the influence of sex and body mass index (BMI).

SUBJECTS/METHODS

Fifty three healthy, ambulatory men (n=26, age:32.5±9.4 years) and women (n=27, age:35.2±10.3 years) received repeat MFBIA measurements (six measurements from 0 to 15 min). Agreement and precision were evaluated for each condition and paired time points.

RESULTS

Significant TBW sex differences from supine posture were observed for walking (females) and sitting (males) postures. For BMI (⩽24.9 kg m^-2) significant TBW differences from supine were observed for both sitting and walking and significant ECW differences from sitting were also observed with both supine and walking. There was no significant effect of sex or BMI (⩾25.0 kg m^-2) on ECW measures. Irrespective of sex or BMI, there was close agreement in TBW and ECW precision over the three protocols.

CONCLUSIONS

Practitioners can have confidence in the precision of TBW and ECW measurements within a 15 min time period and pre-testing conditions (supine, sitting or walking) in healthy subjects, though must be cautious in assessments when pre-test postures change. Further research to examine the impact of pre-testing procedures on stand-on MFBIA BIA measurements, including subjects with fluid disturbance, is warranted.

Higher skeletal muscle mass may protect against ischemic stroke in community-dwelling adults without stroke and dementia: The PRESENT project

Background

It is well known that a low skeletal muscle mass (SMM) is associated with stroke. However, it is unknown whether increasing muscle mass can prevent stroke.

Methods

This community-based cross-sectional study was supported by the regional government. SMM measurements and brain computed tomography was performed in 722 stroke-free and dementia-free subjects (aged 50–75 years). Subjects were divided into quartiles (Q) by SMM, checked using the bioelectrical impedance analysis method (InBody 770, InBody, Seoul, Korea). Odds ratios (ORs) of brain white matter changes/silent infarction (WMC/SI) were calculated. The subjects were then divided into two groups by sex and evaluated.

Results

In the analysis of the four groups, the unadjusted ORs of Q2–Q4 were 0.616 (95% confidence interval [CI], 0.372–1.022; P = 0.061), 0.290 (CI, 0.159–0.530; P < 0.001), and 0.209 (CI, 0.108–0.403; P < 0.001) for the risk of WMC/SI. Adjusted ORs for age, hypertension, diabetes mellitus, education, hypercholesterolemia, and smoking were 0.994 (CI, 0.513–1.740; P = 0.085), 0.669 (CI, 0.329–1.362; P = 0.268), and 0.464 (CI, 0.219–0.984; P = 0.045). In the two–group (dichotomized) analysis, the unadjusted OR for the higher muscle mass groups (Q3 + Q4) was 0.313 (CI, 0.200–0.491; P < 0.001). The adjusted OR was 0.577 (CI, 0.340–0.979; P = 0.042). Considering sex, the adjusted OR were 0.351 (CI, 0.141–0.869; P = 0.024) in men and 0.771 (CI, 0.391–1.519; P = 0.452) in women.

Conclusions

Our findings suggest that increased SMM may protect against WMC/SI, especially in men.

Total body composition estimated by standing-posture 8-electrode bioelectrical impedance analysis in male wrestlers

Standing-posture 8-electrode bioelectrical impedance analysis is a fast and practical method for evaluating body composition in clinical settings, which can be used to estimate percentage body fat (BF%) and skeletal muscle mass in a subject’s total body and body segments. In this study, dual-energy X-ray absorptiometry (DXA) was used as a reference method for validating the standing 8-electrode bioelectrical impedance analysis device BC-418 (BIA₈, Tanita Corp., Tokyo, Japan). Forty-eight Taiwanese male wrestlers aged from 17.9 to 22.3 years volunteered to participate in this study. The lean soft tissue (LST) and BF% in the total body and body segments were measured in each subject by the BIA₈ and DXA. The correlation coefficients between total body, arm, leg segments impedance index (BI, ht²/Z) and lean soft tissue mass measured from DXA were r = 0.902, 0.453, 0.885, respectively (p < 0.01). In addition, the total body and segmental LST estimated by the BIA₈ were highly correlated with the DXA data (r = 0.936, 0.466, 0.886, p < 0.01). The estimation of total body and segmental BF% measured by BIA₈ and DXA also showed a significant correlation (r > 0.820, p < 0.01). The estimated LST and BF% from BIA₈ in the total body and body segments were highly correlated with the DXA results, which indicated that the standing-posture 8-electrode bioelectrical impedance analysis may be used to derive reference measures of LST and BF% in Taiwanese male wrestlers.

Contribution of branched-chain amino acids to purine nucleotide cycle: a pilot study

BACKGROUND/OBJECTIVES

Branched-chain amino acids (BCAAs) and purine nucleotide cycle (PNC) are both associated with energy metabolism. The purpose of this study was to explore the influences of BCAA supplementation on the PNC activity of male athletes in response to a bout of endurance running exercise.

SUBJECTS/METHODS

Twelve male athletes (20.3±1.4 years) participated in the study. Each of the athletes received 12 g of a BCAA supplement (leucine 54%, isoleucine 19% and valine 27%) per day during the study. They performed two identical 60-min running exercises (65-70% maximum heart rate reserved) before and after receiving the BCAA supplements for 15 days. In addition to body composition measurement, plasma and urinary samples were also collected. Plasma samples were examined for the concentrations of glucose, lactate, BCAAs, alanine, glutamine, aspartate, hypoxanthine and uric acid. Urinary samples were examined for the concentrations of urea nitrogen, hydroxyproline, 3-methylhistidine and creatinine.

RESULTS

Body composition and the concentrations of urinary metabolites were not affected by BCAA supplementation, whereas clearance of plasma lactate after recovery from exercise was enhanced by BCAA supplementation (P<0.05). Plasma aspartate concentration was increased (P<0.05), whereas plasma glutamine, hypoxanthine and uric acid concentrations were decreased (P<0.05) by BCAA supplementation.

CONCLUSIONS

The findings suggest that BCAA supplements not only provided additional substrate to meet the energy demands of the athletes during endurance exercise but also reduced their PNC activity, and subsequently decreased uric acid production and reduced the incidence of gout in a person engaging in endurance exercise.

Shortage of Appendicular Skeletal Muscle Is an Independent Risk Factor for Mortality in Peritoneal Dialysis Patients

♦ BACKGROUND: Limited data are available on clinical outcomes among peritoneal dialysis patients with shortage of appendicular skeletal muscle (ASM). In this study, we tested the hypothesis that the shortage of ASM is an independent risk factor for mortality in continuous ambulatory peritoneal dialysis (CAPD) patients. ♦ METHODS: Adult patients undergoing CAPD between March and August 2007 in a single center in China were recruited in this prospective cohort study. Body composition, protein/energy intake, clinical, and biochemical data were collected at baseline, 6 months, and 12 months. End points were all-cause mortality by 12 September 2014. The mean follow-up time was 60.21 (± 24.45) months (11.00 - 89.00). ♦ RESULTS: Compared with the baseline, the mean value of ASM in CAPD patients decreased at 12 months (19.40 ± 5.60 vs 21.85 ± 6.14, p < 0.001). According to the estimation of patient survival by Kaplan-Meier, patients with a shortage of ASM had a worse survival rate than those with normal ASM (χ² = 16.588, p < 0.001). In the Cox's proportional hazards model, patients' survival was independently associated with a shortage of ASM (hazard ratio [HR] = 2.318, p = 0.024, 95% confidence interval [CI] = 1.116 - 4.812). Standard daily protein intake (stDPI) and standard daily energy intake (stDEI) in patients with a shortage of ASM were significantly lower than those in patients with normal ASM in the first follow-up year (t = 2.067, p = 0.041; t = 3.673, p = 0.001). ♦ CONCLUSIONS: A shortage of ASM is an independent risk factor for mortality in CAPD patients. Further studies are needed to demonstrate that nutritional intervention helps with improving muscle mass and, consequently, the survival of CAPD patients.

Genetic Variants in Interleukin-28B Are Associated with Diabetes and Diabetes-Related Complications in Patients with Chronic Hepatitis C Virus Infection

BACKGROUND

Few studies have shown that host interleukin-28B (IL28B) genetic polymorphisms are associated with insulin resistance in patients with chronic hepatitis C virus (HCV) infection. However, the clinical relevance of this relationship is unclear.

AIMS

We examined the association between IL28B genotype for rs12980275 and risk of type 2 diabetes and diabetes-related complications.

METHODS

We used a cross-sectional study of prospectively recruited male veterans with chronic HCV. We employed logistic regression analysis and adjusted for patients' age, race, body mass index, and hepatic fibrosis.

RESULTS

A total of 528 participants were recruited (mean age 59.1 years; 38.5 % African-American; 40.3 % advanced fibrosis). Of these, 36.1 % were homozygous for favorable AA allele for rs12980275, 49.0 % were heterozygous (AG), and 14.0 % were homozygous for the unfavorable allele (GG). Prevalence of diabetes was significantly lower in patients with both favorable alleles (AA) than that with at least one unfavorable IL28B G allele (21.1 vs. 30.2 %, p = 0.02). Similarly, patients who were homozygous for the favorable alleles had lower prevalence of diabetes-related complications than patients with any unfavorable IL28B allele (5.7 vs. 12.2 %, p = 0.01). This association did not change after adjusting for sociodemographic characteristics, body mass index, and stage of hepatic fibrosis (adjusted ORdiabetes 0.56, 95 % CI 0.35-0.89; ORdiabetes-related complications 0.47, 95 % CI 0.23-0.96).

CONCLUSIONS

Patients who have favorable AA IL28B alleles have a lower prevalence of diabetes and related complications compared with patients with unfavorable IL28B rs12980275 genotype. IL28B genotype information may be used to counsel HCV patients regarding their individualized risk of diabetes and diabetes-related complications.

Cardiorespiratory fitness and body composition in postmenopausal women

The object of the study was to analyze the relationship between aerobic fitness and body composition in postmenopausal women. We hypothesized that postmenopausal women that had higher adiposity had lower cardiorespiratory capacity, regardless of the characteristics of menopause. The sample included 208 women (57.57 ± 6.62 years), whose body composition and the basal metabolic rate were evaluated by octopolar bioimpedance (InBody 720) and the oxygen uptake by the modified Bruce protocol. Most of the sample showed obesity and a high visceral fat area. The visceral fat area and the basal metabolic rate explained 30% of the variation of oxygen uptake, regardless of age, time, nature or hormone therapy. The values of the latter variables were reduced in the presence of high central adiposity (−6.16 ml/kg/min) and the basal metabolic rate of less than 1238 kcal/day (−0.18 ml/kg/min). The women with oxygen uptake above 30.94 ml/kg/min showed lower values of total and central adiposity when compared with other groups. With an increase of aerobic fitness, there was a growing tendency of the average values of the soft lean mass index, with differences between the groups low-high and moderate-high. These results suggest worsening of the cardiorespiratory condition with an increase of central adiposity and a decrease of the BMR, regardless of age and menopause characteristics.

The correlates of body composition with heart rate recovery after step test: an exploratory study of Malaysian adolescents

BACKGROUND

In adults, heart rate recovery is a predictor of mortality, while in adolescents it is associated with cardio-metabolic risk factors. The aim of this study was to examine the relationship between body composition measures and heart rate recovery (HRR) after step test in Malaysian secondary school students.

METHODS

In the Malaysian Health and Adolescents Longitudinal Research Team (MyHEART) study, 1071 healthy secondary school students, aged 13 years old, participated in the step test. Parameters for body composition measures were body mass index z-score, body fat percentage, waist circumference, and waist height ratio. The step test was conducted by using a modified Harvard step test. Heart rate recovery of 1 minute (HRR1min) and heart rate recovery of 2 minutes (HRR2min) were calculated by the difference between the peak pulse rate during exercise and the resting pulse rate at 1 and 2 minutes, respectively. Analysis was done separately based on gender. Pearson correlation analysis was used to determine the association between the HRR parameters with body composition measures, while multiple regression analysis was used to determine which body composition measures was the strongest predictor for HRR.

RESULTS

For both gender groups, all body composition measures were inversely correlated with HRR1min. In girls, all body composition measures were inversely correlated with HRR2min, while in boys all body composition measures, except BMI z-score, were associated with HRR2min. In multiple regression, only waist circumference was inversely associated with HRR2min (p=0.024) in boys, while in girls it was body fat percentage for HRR2min (p=0.008).

CONCLUSION

There was an inverse association between body composition measurements and HRR among apparently healthy adolescents. Therefore, it is important to identify cardio-metabolic risk factors in adolescent as an early prevention of consequent adulthood morbidity. This reiterates the importance of healthy living which should start from young.

Effect of fasting in Ramadan on body composition and nutritional intake: a prospective study

BACKGROUND

The present study aimed to assess the effects of Ramadan intermittent fasting on body weight and composition and the effects of age and sex.

METHODS

Body weight, height, waist and hip circumferences were measured, body mass index (BMI) was calculated and fat mass, fat-free mass and percentage body fat were assessed by bioelectrical impedance on 240 adult subjects (male: 158) who fasted between sunrise and sunset for at least 20 days. Measurements were taken 1 week before and 1 week after Ramadan. Energy and macronutrient intakes were assessed using a 3-day food frequency questionnaire on a sub-sample of subjects before and during Ramadan.

RESULTS

Subjects were grouped according to age and sex: ≤35 years (n = 82, males: 31) and 36-70 years (n = 158, males: 127). There were significant reductions in weight and BMI (P < 0.001) in almost all subjects, with the biggest being in males ≤35 years [-2.2% (SE 2.2%), P < 0.001]. Waist and hip circumferences fell in most subjects, except females aged 36-70 years. Fat mass fell in most subjects, ranging from 2.3% to 4.3% from baseline, except in females aged 36-70 years who did not experience a significant change. Fat-free mass was significantly reduced in all subjects (P < 0.001), whereas percentage body fat was lower only in males by 2.5% (SE 3.2%) (P = 0.029) in those aged ≤35 years and by 1.1% (SE 1.5%) (P < 0.001) in those aged 36-70 years. Dietary intake was similar before and during Ramadan, except in males whose protein intake fell during Ramadan (P = 0.032).

CONCLUSIONS

Ramadan fasting leads to weight loss and fat-free mass reductions. Body composition changes vary depending on age and sex.

Racial differences in the association between adiposity measures and the risk of hepatitis C-related liver disease

BACKGROUND

African Americans have lower reported likelihood of hepatitis C virus-related cirrhosis than whites. It is unknown whether relative differences in the distribution of adipose tissue, lean mass, and other anthropometric measurements may explain these observed interethnic differences in disease risk.

AIM

: To evaluate the association between anthropometric measurements and advanced liver disease in a cross-sectional study of African American and white male veterans.

METHODS

We used the validated FibroSURE-ActiTest to assess hepatic pathology, and direct segmental multichannel bioelectric impedance analysis for anthropometric measurements. Race-stratified logistic regression was employed to evaluate risk of high fibrosis progression rate (FPR) and advanced inflammation (A2 to A3).

RESULTS

Among 330 eligible males (59% African American), there were 43 white and 57 African American males with high FPR, and 70 African American and 59 white with advanced inflammation. Percentage body fat (%BF) was a stronger predictor of high FPR risk than was a high body mass index in African Americans [odds ratio (OR)(adj)=2.08; 95% confidence interval (CI),0.83-5.23 for highest %BF vs. lowest tertile and OR(adj)=1.50; 95% CI,0.60-3.75 for obese vs. normal body mass index, respectively], but not in whites. Highest lean leg mass was associated with a nonsignificant increased risk of both high FPR and advanced inflammation in African Americans (OR(highFPRadj)=1.73; 95% CI, 0.73-4.10; OR(AdvancedinflammationAdj)=1.65; 95% CI, 0.76-3.56) versus a decreased risk of both in whites (OR(highFPRadj)=0.62; 95% CI, 0.21-1.79; OR(AdvancedinflammationAdj)=0.58; 95% CI, 0.22-1.48).

CONCLUSIONS

Interethnic differences in nontraditional anthropometric measurements like %BF suggests their potential role in understanding interethnic differences in hepatitis C virus-related liver disease risk in males.

Common genetic variation in the IGF1 associates with maximal force output

PURPOSE

We clarified the effect of insulin-like growth factor-1 (IGF1), IGF-binding protein-3 (IGFBP3), interleukin-6 (IL6), and its receptor (IL6R) gene variants on muscular and aerobic performance, body composition, and on circulating levels of IGF-1 and IL-6. Single nucleotide polymorphisms (SNPs) may, in general, influence gene regulation or its expression, or the structure and function of the corresponding protein, and modify its biological effects. IGF-1 is involved in the anabolic pathways of skeletal muscle. IL-6 plays an important role in muscle energy homeostasis during strenuous physical exercise.

METHODS

Eight hundred forty-one healthy Finnish male subjects of Caucasian origin were genotyped for IGF1 (rs6220 and rs7136446), IGFBP3 (rs2854744), IL6 (rs1800795), and IL6R (rs4537545) SNPs, and studied for associations with maximal force of leg extensor muscles, maximal oxygen consumption, body fat percent, and IGF-1 and IL-6 levels. Analytic methods included dynamometer, bicycle ergometer, bioimpedance, ELISA, and polymerase chain reaction assays.

RESULTS

All investigated SNPs conformed to Hardy-Weinberg equilibrium with allele frequencies validated against CEU population. Genotype CC of rs7136446 associated with higher body fat and increased maximal force production. Genotype CC of the IGFBP3 SNP rs2854744 and TT genotype of the IL6R SNP rs4537545 associated with higher IL-6 levels. In logistic regression analysis, allele C of the rs2854744 decreased odds for lower body fat. None of the studied SNPs associated with aerobic performance.

CONCLUSIONS

Our data suggest that common variation in the IGF1 gene may affect maximal force production, which can be explained by the role of IGF-1 in the anabolic pathways of muscle and neurotrophy. Variations in the IGF1 and IGFBP3 gene may result in higher body fat and be related to alterations of IGF-1-mediated tissue growth.

Higher serum testosterone is associated with increased risk of advanced hepatitis C-related liver disease in males

Males have strikingly increased risk of advanced liver disease. However, the association between testosterone and risk of hepatitis C virus (HCV)-related advanced liver disease is unknown. We performed a cross-sectional study in male veterans with chronic HCV. Blood samples were obtained to measure total serum testosterone and perform the FibroSURE-ActiTest. Other risk-factor data were obtained through systematic questionnaires (e.g., alcohol), physical measurements (e.g., body mass index), and serological tests (e.g., viral load). The association between total testosterone and risk of advanced hepatic fibrosis (F3 and F3/F4) and inflammatory activity (A3 and A2/3) measured by the FibroSURE-ActiTest was evaluated with logistic regression. A total of 308 eligible study participants were prospectively recruited (mean age: 57; 52% African-American). There were 105 cases with advanced fibrosis and 203 mild fibrosis controls as well as 88 cases with advanced inflammatory activity and 220 mild activity controls. Mean total serum testosterone was significantly higher in advanced fibrosis cases as well as advanced inflammatory activity cases, compared to mild disease controls (6.0 versus 5.3 ng/mL and 5.9 versus 5.4 ng/mL, respectively). We observed a significant 25% increase in advanced fibrosis risk and 15% increase in advanced inflammatory activity risk for each 1-ng/mL increase in total serum testosterone. Total testosterone in the upper tertile was associated with an even greater excess risk of advanced fibrosis than advanced inflammatory activity (odds ratio [OR](adjusted advanced fibrosis) = 3.74; 95% CI: 1.86-6.54 versus OR(adjusted advanced inflammatory activity) = 2.23; 95% CI: 1.07-4.93, respectively).

CONCLUSIONS

Total serum testosterone is associated with an increased risk of both advanced hepatic fibrosis and advanced hepatic inflammatory activity in HCV-infected men. Testosterone may be important in the pathogenesis of HCV-related advanced liver disease in males.

External cross-validation of bioelectrical impedance analysis for the assessment of body composition in Korean adults

Bioelectrical impedance analysis (BIA) models must be validated against a reference method in a representative population sample before they can be accepted as accurate and applicable. The purpose of this study was to compare the eight-electrode BIA method with DEXA as a reference method in the assessment of body composition in Korean adults and to investigate the predictive accuracy and applicability of the eight-electrode BIA model. A total of 174 apparently healthy adults participated. The study was designed as a cross-sectional study. FM, %fat, and FFM were estimated by an eight-electrode BIA model and were measured by DEXA. Correlations between BIA_%fat and DEXA_%fat were 0.956 for men and 0.960 for women with a total error of 2.1%fat in men and 2.3%fat in women. The mean difference between BIA_%fat and DEXA_%fat was small but significant (P < 0.05), which resulted in an overestimation of 1.2 ± 2.2%fat (95% CI: -3.2-6.2%fat) in men and an underestimation of -2.0 ± 2.4%fat (95% CI: -2.3-7.1%fat) in women. In the Bland-Altman analysis, the %fat of 86.3% of men was accurately estimated and the %fat of 66.0% of women was accurately estimated to within 3.5%fat. The BIA had good agreement for prediction of %fat in Korean adults. However, the eight-electrode BIA had small, but systemic, errors of %fat in the predictive accuracy for individual estimation. The total errors led to an overestimation of %fat in lean men and an underestimation of %fat in obese women.

Influence of obesity and sarcopenic obesity on plantar pressure of postmenopausal women

BACKGROUND

Menopause is associated with a decrease in fat-free mass and an increase in fat mass. Sarcopenic obesity is more strongly associated with physical limitations than either obesity or sarcopenia and their effect in plantar pressure is not known. Consequently, the scope of the present study was to examine the effect of obesity and sarcopenic obesity on plantar pressure of postmenopausal women, during walking.

METHODS

Body composition and biomechanics parameters of plantar pressure were assessed in 239 postmenopausal women.

FINDINGS

Compared to non-obese and non-sarcopenic women, obese postmenopausal women have higher peak pressure in the metatarsal areas 1, 4, 5, midfoot and lateral heel and higher absolute impulses in all metatarsal and heel areas. On the other hand, sarcopenic obese postmenopausal women presented higher peak pressure and absolute impulses under all metatarsal areas, midfoot and heels. When the absolute values of maximal peak pressures and absolute impulses were normalised to body mass, pressure increases were only perceived for midfoot.

INTERPRETATION

The pressure increase found in different foot areas of obese and particularly in sarcopenic obese could cause discomfort and pain in the foot. Sarcopenic obese postmenopausal women also present a higher loading during the stance phase comparing with non-sarcopenic non-obese, fact that might limit their basic daily activity tasks, such as walking.

New method of predicting dry weight using bioelectrical impedance analysis in haemodialysis patients

AIM

There were significant differences in the slopes of the ultrafiltration (UF) amount removed during haemodialysis (HD) sessions versus the percentage change in the extracellular fluid/total body water ratio for the right lower extremity (ECF/TBW(right leg)) plot in normohydrated (NH) and overhydrated states. The purpose of this study was to develop and validate a method for predicting dry weight (DW) using these results.

METHODS

It was hypothesized that for patients to become NH, the slope of the UF amount versus the percentage changes in ECF/TBW(right leg) plot should be same as that of NH patients and a method for predicting DW was developed. To validate the accuracy of this method, the ECF/TBW(right leg) was measured by eight-point tactile-electrode bioelectrical impedance analysis before and after HD in 17 newly enrolled NH patients. Using the current DW (cDW) of subjects as a reference, we compared the accuracies of pDW1 (our devised method) and pDW2 (the normovolaemia/hypervolaemia slope method).

RESULTS

The mean cDW, pDW1 and pDW2 values were 56.8 +/- 7.9, 56.4 +/- 7.7 and 56.3 +/- 8.0 kg, respectively. No significant differences existed between cDW, pDW1 and pDW2. pDW1 had a lower root mean square error than pDW2 (1.12 vs 1.69). On the Bland-Altman plot, differences between pDW1 and cDW were closer to zero than between pDW2 and cDW.

CONCLUSION

A new method was developed of predicting the DW using the relationship between the UF amount and the percentage change in the ECF/TBW ratio of the lower extremities after HD. The devised method appears to be as accurate as the normovolaemia/hypervolaemia slope method.

Japanese study to organize proper lifestyle modifications for metabolic syndrome (J-STOP-MetS): design and method

Prevalence of the metabolic syndrome is now a very serious health problem in Japan and a public preventive strategy is essential to reduce morbidity. A systematic interventional strategy for the metabolic syndrome remains to be established. In order to address this issue, a multi-center study; Japanese Study to Organize Proper lifestyle modification for the metabolic syndrome (J-STOP-MetS), has been established by nine preventive medical centers among Rosai hospital groups. This study comprises a cross-sectional study (J-STOP-MetS 1) and a prospective randomized control study (J-STOP-MetS 2). J-STOP-MetS 1 examines the causes of the metabolic syndrome by means of a questionnaire in a large cohort of patients with the metabolic syndrome and control subjects matched for age and sex. J-STOP-MetS 2 examines the hypothesis that guidance on lifestyle modifications will help at risk patients to reduce abdominal fat and cardiovascular risk factors. The metabolic syndrome patients are randomly assigned either to a single visit to a guidance group or multiple visits every two months. The individualized guidance is provided by the coordination of physician, trained nurse, dietician and exercise trainer. Several parameters are measured before and six months after the first guidance session, including, body weight, waist circumference, blood pressure, several blood markers and arterial stiffness. The J-STOP-MetS is the first large-scale clinical study of the metabolic syndrome in Japan and should provide important evidence for the practical management of the metabolic syndrome.

Cross-validation of bioelectrical impedance analysis for the assessment of body composition in a representative sample of 6- to 13-year-old children

BACKGROUND/OBJECTIVES

(1) To cross-validate tetra- (4-BIA) and octopolar (8-BIA) bioelectrical impedance analysis vs dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition and (2) to evaluate the accuracy of external 4-BIA algorithms for the prediction of total body composition, in a representative sample of Swiss children.

SUBJECTS/METHODS

A representative sample of 333 Swiss children aged 6-13 years from the Kinder-Sportstudie (KISS) (ISRCTN15360785). Whole-body fat-free mass (FFM) and appendicular lean tissue mass were measured with DXA. Body resistance (R) was measured at 50 kHz with 4-BIA and segmental body resistance at 5, 50, 250 and 500 kHz with 8-BIA. The resistance index (RI) was calculated as height(2)/R. Selection of predictors (gender, age, weight, RI4 and RI8) for BIA algorithms was performed using bootstrapped stepwise linear regression on 1000 samples. We calculated 95% confidence intervals (CI) of regression coefficients and measures of model fit using bootstrap analysis. Limits of agreement were used as measures of interchangeability of BIA with DXA.

RESULTS

8-BIA was more accurate than 4-BIA for the assessment of FFM (root mean square error (RMSE)=0.90 (95% CI 0.82-0.98) vs 1.12 kg (1.01-1.24); limits of agreement 1.80 to -1.80 kg vs 2.24 to -2.24 kg). 8-BIA also gave accurate estimates of appendicular body composition, with RMSE < or = 0.10 kg for arms and < or = 0.24 kg for legs. All external 4-BIA algorithms performed poorly with substantial negative proportional bias (r> or = 0.48, P<0.001).

CONCLUSIONS

In a representative sample of young Swiss children (1) 8-BIA was superior to 4-BIA for the prediction of FFM, (2) external 4-BIA algorithms gave biased predictions of FFM and (3) 8-BIA was an accurate predictor of segmental body composition.

Ability of new octapolar bioimpedance spectroscopy analyzers to predict 4-component-model percentage body fat in Hispanic, black, and white adults

BACKGROUND

New, vertical, 8-electrode bioimpedance spectroscopy (BIS) analyzers provide detailed body-composition and nutritional information within 2 min. This is the first report on BIS's accuracy in predicting relative fatness [percentage body fat (%BF)] in a heterogeneous sample according to a multicomponent model criterion.

OBJECTIVE

We compared %BF measurements from 2 BIS devices with those from a multicomponent model in a sample of Hispanic, black, and white adults.

DESIGN

Equal numbers of apparently healthy men and women (n = 75 of each) from each racial-ethnic group, diverse in body mass index and age, volunteered. Reference %BF (%BF(4C)) was computed by using a 4-component (4C) model with total bone mineral content obtained from dual-energy X-ray absorptiometry, body density from underwater weighing with measured residual lung volume, and total body water from traditional BIS. Estimations from InBody 720 (%BF(720)) and InBody 320 (%BF(320)) BIS analyzers were validated against %BF(4C).

RESULTS

The %BF(720) (r = 0.85, SEE = 5.19%BF) and %BF(320) (r = 0.84, SEE = 5.17%BF) correlations were significant (P < 0.05) in the men; main effects were nonsignificant. Correlations for %BF(720) (r = 0.88, SEE = 4.85%BF) and %BF(320) (r = 0.89, SEE = 4.82%BF) also were significant in the women (P < 0.05); there was a main effect for method but not race-ethnicity. There were no sex-specific overestimations or underestimations at the extremes of the distributions.

CONCLUSIONS

BIS estimates of %BF(4C) were well correlated in men and women. There were no significant methodologic differences in the men. The %BF(4C) was significantly underestimated by %BF(720) and %BF(320) in the women.