Validation of bioelectrical-impedance analysis as a measurement of change in body composition in obesity

Impaired eating behaviors but intact metabolic hormone levels in individuals with major depressive disorder and generalized anxiety disorder

BACKGROUND

Major depressive disorder (MDD) and generalized anxiety disorder (GAD) contribute significantly to global health burdens. Identifying disease markers for these comorbid disorders can increase understanding of pathogenesis and improve screening and intervention strategies. This study examined the association of physical health factors with MDD and MDD + GAD, across sexes.

METHODS

Two samples of participants from the Tulsa-1000 study (exploratory cohort: N = 136; confirmatory cohort: N = 185) completed body composition measurements, eating behavior (Three Factor Eating Questionnaire [TFEQ], Eating Disorder Diagnostic Scale [EDDS]), exercise questionnaires, and a blood draw. Metabolic hormone concentrations (leptin, insulin, and adiponectin) were analyzed from blood samples. Within each cohort, a two-way analysis of variance compared three groups (MDD, MDD + GAD, and healthy controls [HC]), sex, and their interaction on dependent variables. Hedges g was calculated to reflect effect size magnitude.

RESULTS

Medium-to-large group main effects across cohorts indicated that compared to HC: (1) MDD (g = 1.71/0.57) and MDD + GAD (g = 0.93/0.69) reported higher TFEQ Disinhibition scores; (2) MDD endorsed higher TFEQ Hunger scores (g = 0.66/0.48); and (3) MDD (g = 1.60/1.30) and MDD + GAD (g = 0.92/1.72) reported greater EDDS scores. Large sex main effects across cohorts indicated that females exhibited higher levels than males for percent body fat (g = 1.07/1.17), leptin (g = 1.27/1.12), and adiponectin (g=0.82/0.88).

LIMITATIONS

The power to detect group*sex interactions was limited due to a greater number of females (than males) in the study, and over half of clinical participants were taking medications.

CONCLUSIONS

Individuals with MDD and MDD + GAD demonstrate difficulties in regulating eating behaviors, potentially contributing to functional impairment and increased disease burden.

Combined use of handgrip strength and hemoglobin as markers of undernutrition in patients with stage 3-5 chronic kidney disease

BACKGROUND AND AIMS

The early identification of undernourished patients with CKD could help instating appropriate nutritional intervention before the full development of the threatening condition known as Protein Energy Wasting (PEW). Handgrip strength (HGS) and blood hemoglobin (Hb) concentration are two parameters considered representative of nutritional status but not included among the criteria for PEW diagnosis. In the present work we investigated whether they could help identifying CKD patients at risk of undernutrition.

METHODS AND RESULTS

We performed a two-step cluster analysis to classify a cohort of 71 stage 3-5 CKD patients, none of which with PEW, according to their Hb concentration and dominant-hand HGS. Two clusters were finely separated using this method. When we compared the two groups for main body composition and nutritional variables by using t-test statistics or Mann-Whitney test, as appropriate, we found significant differences in PhA, ECW/TBW, ASMI, serum iron. Then we stratified our population by gender and performed cluster analysis as well. PhA, ECW/TBW were still significantly different in the two clusters both in M and in F, while serum iron concentration only in males and ASMI only in females.

CONCLUSION

These results suggest that either in male than in female Hb concentration and HGS may distinguish two subgroups of CKD patients with different nutritional status and disease severity. Patient belonging to either of these cluster can be easily identified by using the HGS/Hb ratio which represents the HGS normalized per gr Hb.

Prognostic role of body composition in peritoneal carcinomatosis patients undergoing cytoreduction and hyperthermic intraperitoneal chemotherapy

BACKGROUND

Bioelectric impedance analysis (BIA)-measured body composition and nutritional status have been used as prognostic indicators in various cancer cohorts. This study investigated whether BIA could provide information on prognosis in peritoneal carcinomatosis patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

We retrospectively analyzed the data of 99 patients with preoperative BIA data among those who underwent CRS and HIPEC. The association between BIA-derived parameters and intraoperative peritoneal cancer index (PCI) score was assessed. Predictive analysis for the occurrence of postoperative morbidities including major complications (Clavien-Dindo classification 3-4) and re-admission within 30 days after surgery as well as 1 year mortality was also performed.

RESULTS

BIA-derived mineral (r = 0.224, p = 0.027), fat (r =  - 0.202, p = 0.048), and total body water (TBW)/fat-free mass (FFM) (r =  - 0.280, p = 0.005) showed significant associations with intraoperative PCI score. Lower TBW/FFM was an independent predictor of major postoperative complications (OR 0.047, 95% CI 0.003-0.749, p = 0.031) and re-admission (OR 0.094, 95% CI 0.014-0.657, p = 0.017) within 30 days after surgery. Higher fat mass was also independently associated with a higher risk of major postoperative complications (OR 1.120, 95% CI 1.006-1.248, p = 0.039) and re-admission (OR 1.123, 95% CI 1.024-1.230, p = 0.013). Intraoperative PCI score > 20 (OR 4.489, 95% CI 1.191-16.917, p = 0.027) and re-admission within 30 days after surgery (OR 5.269, 95% CI 1.288-21.547, p = 0.021) independently predicted postoperative 1-year mortality.

CONCLUSIONS

We demonstrate that preoperative BIA-derived TBW/FFM and fat mass were significantly correlated with metastatic extent, assessed by PCI score, in patients with peritoneal carcinomatosis. In addition, BIA-derived TBW/FFM and fat mass showed independent predictability for postoperative 30-day major complications and re-admission in patients undergoing CRS and HIPEC. Our findings suggest that assessment of BIA may improve discrete risk stratification in patients who are planned to receive CRS and HIPEC.

Circumference-Based Predictions of Body Fat Revisited: Preliminary Results From a US Marine Corps Body Composition Survey

Purpose: Body composition assessment methods are dependent on their underlying principles, and assumptions of each method may be affected by age and sex. This study compared an abdominal circumference-focused method of percent body fat estimation (AC %BF) to a criterion method of dual-energy x-ray absorptiometry (DXA), and a comparative assessment with bioelectrical impedance (BIA), in younger (≤30 years) and older (>age 30 years) physically fit (meeting/exceeding annual US Marine Corps fitness testing requirements) men and women.

Methods: Fit healthy US Marines (430 men, 179 women; 18–57 years) were assessed for body composition by DXA (iDXA, GE Lunar), anthropometry, and BIA (Quantum IV, RJL Systems).

Results: Compared to DXA %BF, male AC %BF underestimated for both ≤30 and >30 years age groups (bias, -2.6 ± 3.7 and -2.5 ± 3.7%); while female AC %BF overestimated for both ≤30 and >30 years age groups (2.3 ± 4.3 and 1.3 ± 4.8%). On an individual basis, lean men and women were overestimated and higher %BF individuals were underestimated. Predictions from BIA were more accurate and reflected less relationship to adiposity for each age and sex group (males: ≤30, 0.4 ± 3.2, >30 years, -0.5 ± 3.5; women: ≤30, 1.4 ± 3.1, >30 years, 0.0 ± 3.3). Total body water (hydration) and bone mineral content (BMC) as a proportion of fat-free mass (FFM) remained consistent across the age range; however, women had a higher proportion of %BMC/FFM than men. Older men and women (>age 30 years) were larger and carried more fat but had similar FFM compared to younger men and women.

Conclusion: The AC %BF provides a field expedient method for the US Marine Corps to classify individuals for obesity prevention, but does not provide research-grade quantitative body composition data.

Fat-to-Muscle Ratios and the Non-Achievement of LDL Cholesterol Targets: Analysis of the Korean Genome and Epidemiology Study

Maintaining optimal low-density lipoprotein (LDL) cholesterol levels is necessary to prevent cardiovascular disease (CVD). Excessive fat mass and decreased muscle mass are both associated with increased risks of developing dyslipidemia. Thus, we investigated the longitudinal relationship between the fat-to-muscle ratio (FMR) and the non-achievement of LDL cholesterol targets. We analyzed a total of 4386 participants aged 40–69 years from the Korean Genome and Epidemiology Study. FMR was defined as the ratio of total fat mass to total muscle mass, measured by bioelectrical impedance. The non-achievement of an LDL cholesterol target was defined as an LDL cholesterol level higher than the established target level according to individual CVD risk. The adjusted hazard ratios and 95% confidence interval for the incidence of non-achievement of LDL cholesterol targets for the sex-specific middle and highest tertiles vs. the referent lowest tertile of FMR were 1.56 (1.29–1.90) and 1.86 (1.47–2.31) in men and 1.40 (1.18–1.66) and 1.31 (1.06–1.62) in women after adjusting confounders. Our findings suggest that FMR, a novel indicator of the combined effects of fat and muscle mass, is useful for predicting non-achievement of LDL cholesterol targets.

Comparison of Bioelectrical Impedance Analysis and Computed Tomography on Body Composition Changes Including Visceral Fat After Bariatric Surgery in Asian Patients with Obesity

PURPOSE

The accuracy of bioelectrical impedance analysis (BIA) in patients with obesity has been controversial. This study aimed to validate the use of BIA in detecting body composition changes, especially for visceral fat, before and after bariatric surgery using computed tomography (CT) as a reference method.

MATERIALS AND METHODS

This retrospective study included Korean patients with a BMI of ≥ 35, or ≥ 30 with metabolic comorbidities. All patients underwent bariatric surgery, and underwent BIA and CT evaluation before and 6 months after the operation. The skeletal muscle index (SMI) and visceral fat index (VFI), variables corrected for height, were compared between BIA and CT.

RESULTS

Forty-eight patients (18 men, 30 women) demonstrated a mean weight loss of 27.5 kg. Significant decreases in both VFI and SMI were observed in both BIA and CT (all p<0.001), with greater VFI change compared to SMI (48.2% vs. 10.4% in CT, respectively). Both pre- and post-operative measurements of VFI and SMI were significantly correlated between BIA and CT (all p<0.05). However, the percent decrease was significantly correlated only with VFI (ρ=0.71, p<0.001). The Bland-Altman analysis showed that BIA underestimated VFI, with a greater degree of underestimation in subjects with higher VFI.

CONCLUSION

Despite the underestimation of BIA in measuring visceral fat, BIA VFI was associated with CT VFI. The SMI values showed significant correlations before and after surgery, but not with the percent decrease. Our results suggest that BIA can be a reliable tool for measuring body composition, especially for visceral fat, after bariatric surgery.

An objective measure of energy intake using the principle of energy balance

BACKGROUND

The measurement of energy intake is central to the understanding of energy balance and predicting changes in body weight. Until recently, the most commonly used methods of assessing intake were self-reported diet recalls, diet diaries, or food-frequency questionnaires. These methods, however, are subject to systematic biases and are often inaccurate.

AIM

Review the validations and applications of an expenditure/balance method for measuring energy intake.

METHODS

Review the literature regarding the theory and practice of objectively measuring energy intake based on the principle of energy balance i.e., energy intake is calculated from the measured total energy expenditure plus the change in body energy stores (ES). The attainable precision is modeled and compared with the accuracy and precision of validations against known energy intake.

RESULTS

Measurement of energy intake, calculated in this way, is accurate to within 2% and has a precision of 4-37% depending on the expenditure and body composition methods used and the time interval between measures. Applications of this expenditure/balance (EB) method have provided novel data on the compliance to dietary restriction and its association with physical activity interventions, and the effects of bariatric surgery on energy intake and weight gain. Practical limitations to this method, however, include cost and limited access to the analyses required by the DLW method.

CONCLUSION

The EB method of objectively measuring energy intake is objective, accurate, and reasonably precise. It is practical for moderate-sized studies.

Cross-validation of prediction equations for estimating the body fat percentage in adults with obesity

BACKGROUND & AIM

An accurate estimation of the body fat percentage (BF%) in patients with obesity is of clinical importance. Therefore, we aim to assess the validity of anthropometric-based BF predictive equations in treatment-seeking patients in an outpatient setting.

METHODS

BF% was assessed by Tanita MC-780MA bioimpedance (BIA) and considered as a reference method, and anthropometric-based predictive equations were used in BF% estimations among 275 adults of both genders, in the outpatient clinic of the Department of Nutrition and Dietetics at Beirut Arab University (Lebanon). The mean differences between the measured and estimated BF% values were calculated to assess the accuracy of five equations, and the Bland-Altman method was used to assess the level of agreement.

RESULTS

In both males and females, all predictive equations gave significantly different estimates of BF% when compared to those measured by BIA. On the other hand, in both genders, the mean difference between the BF% value estimated by the Jackson equation and that measured using BIA, was not significant, and agreement was confirmed using Bland-Altman plots.

CONCLUSION

We suggest the Jackson equation for accurate BF% estimation in both genders of patients with obesity in the Lebanese population. However, future studies are still urgently needed to develop and validate new predictive equations suitable for BF% estimations, taking into account ethnicity (i.e., the Arab population).

Development of an Easy-to-Use Prediction Equation for Body Fat Percentage Based on BMI in Overweight and Obese Lebanese Adults

An accurate estimation of body fat percentage (BF%) in patients who are overweight or obese is of clinical importance. In this study, we aimed to develop an easy-to-use BF% predictive equation based on body mass index (BMI) suitable for individuals in this population. A simplified prediction equation was developed and evaluated for validity using anthropometric measurements from 375 adults of both genders who were overweight or obese. Measurements were taken in the outpatient clinic of the Department of Nutrition and Dietetics at Beirut Arab University (Lebanon). A total of 238 participants were used for model building (training sample) and another 137 participants were used for evaluating validity (validation sample). The final predicted model included BMI and sex, with non-significant prediction bias in BF% of −0.017 ± 3.86% (p = 0.946, Cohen’s d = 0.004). Moreover, a Pearson’s correlation between measured and predicted BF% was strongly significant (r = 0.84, p < 0.05). We are presenting a model that accurately predicted BF% in 61% of the validation sample with an absolute percent error less than 10% and non-significant prediction bias (−0.028 ± 4.67%). We suggest the following equations: BF% _females = 0.624 × BMI + 21.835 and BF% _males = 1.050 × BMI − 4.001 for accurate BF% estimation in patients who are overweight or obese in a clinical setting in Lebanon.

The implementation of a physical activity intervention in adults with Obstructive Sleep Apnoea over the age of 50 years: a feasibility uncontrolled clinical trial

Background

Obstructive Sleep Apnoea (OSA) is a risk factor for cardiovascular disease (CVD) and Type 2 diabetes (T2D). Observational studies suggested that OSA treatment might reduce CVD and T2D but RCTs failed to support these observations in part due to poor adherence to continuous positive airway pressure (CPAP). Physical activity (PA) has been shown to have favourable impact on CVD and the risk of T2D independent of its impact on weight and therefore might provide additional health gains to patients with OSA, whether or not adherent to CPAP.

Methods

The main aim of this study was to explore the feasibility of providing a 12-week PA intervention to adults aged over 50 with OSA. The secondary aim was to assess the impact of the PA intervention on OSA severity. Patients with moderate-severe OSA (apnoea hypopnea index (AHI) ≥ 15 events/hour (based on overnight ApneaLink™) were recruited in response to posters displayed in workplaces. A 12-week daily PA intervention was delivered in participant’s home setting and PA was monitored via text and validated by objective PA measures (GT3X accelerometers).

Results

The intervention was feasible as all 10 patients (8 males, mean (SD) age 57.3 (6.01)) completed the intervention and PA increased across the 12-weeks. The duration of PA increased from baseline (113.1 min (64.69) per week to study-end following the intervention (248.4 min (148.31) (p = 0.02). Perceived Exertion (RPE) (physical effort) increased significantly between baseline (M = 10.7 (1.94)) to end of intervention (M = 13.8, (1.56) (p < 0.001). The intervention had no significant impact on weight or composition. Following the intervention, there was a statistically non-significant a reduction in AHI from baseline to study end (22.3 (7.35) vs. 15.8 (7.48); p = 0.09).

Conclusion

It is feasible to deliver a PA intervention to adults aged over 50 with OSA. The intervention resulted in improved PA and AHI levels somewhat and seemingly independent of weight changes. Future trials need to examine whether PA can reduce the burden of OSA associated comorbidities.

Trial registration

CTN: ISRCTN11016312 Retrospectively Registered 21/07/20.

Glucose and protein metabolic responses to an energy- but not protein- restricted diet in type 2 diabetes

AIMS

To test the effect of energy restriction with maintained protein intake on body composition and on insulin sensitivity of glucose and protein metabolism in adults with type 2 diabetes (T2D).

MATERIALS AND METHODS

After 3 days of an isoenergetic diet with 1.2 g/kg/d protein, obese adults with T2D (three women, two men) followed a 5-week diet providing 60% of energy requirements with 45% carbohydrate, and with protein maintained at pre-intervention level. Isotopic tracers were used to quantify whole-body glucose (3-³ H-glucose) and protein (¹³ C-leucine) metabolism pre- (day 4) and post-intervention (day 39), in the postabsorptive state and during a hyperinsulinaemic, isoglycaemic, isoaminoacidaemic clamp. Body composition was measured using dual-energy x-ray absorptiometry.

RESULTS

After energy restriction, 6% weight loss occurred via total body (11%) and visceral fat losses (25%), but lean mass was preserved. Fasting glucose level, serum insulin level, homeostatic model assessment of insulin resistance index and C-peptide level decreased significantly (29%, 38%, 54% and 38%, respectively) as did other cardiometabolic risk factors. Between clamp studies, postabsorptive protein turnover and oxidation rates decreased (12% and 32%), resulting in less negative net balance, consistent with protein conservation. The rates of glucose turnover decreased, and glucose metabolic clearance rate improved (24%). During the clamp, protein flux was lower (9%) and breakdown suppressed (12%), and net balance became less negative but not different. Although glucose turnover did not differ, metabolic clearance improved by 47%.

CONCLUSIONS

In obese adults with T2D, an energy-restricted diet with maintained protein intake of ~1.2 g/kg/d improved the kinetics of protein metabolism (particularly in the postabsorptive state), and preserved lean body mass and increased glucose metabolic clearance rate.

Comparison of bioimpedance body composition in young adults in the Russian Children's Study

BACKGROUND & AIMS

Body mass index is a simple anthropometric measure (kg/m²) used as an indirect estimate of body fat in individuals, and in assessments of population health and comparisons between populations. Bioelectrical impedance analysis (BIA) is often used to provide additional information on body fat and fat-free mass, and has been used to generate body composition reference data in national health surveys. However, BIA measurements are known to be device-specific and there are few published studies comparing results from different BIA instruments. Therefore, we compared the performance of two BIA instruments in the Russian Children's Study (RCS) of male growth, pubertal development and maturation.

METHODS

Paired BIA measurements were obtained using the Tanita BC-418MA (Tanita Corp., Tokyo, Japan) and ABC-01 'Medas' (Medas Ltd, Moscow, Russia) BIA instruments. Cross-sectional data on 236 RCS subjects aged 18-22 years were used for the BIA comparison and the development of a conversion formula between measured resistances; follow-up data (n = 96) were used for validation of the conversion formula.

RESULTS

Whole-body resistances were highly correlated (Spearman rho = 0.95), but fat mass (FM) estimates were significantly higher with the Medas than the Tanita device (median difference 3.3 kg, 95% CI: 2.9, 3.6 kg) with large limits of agreement (LoA) for the FM difference (-2.0, 8.6 kg). A conversion formula between the resistances (Res) was obtained: Medas Res = 0.882 × Tanita Res+26.2 (r² = 0.91, SEE = 17.6 Ohm). After applying the conversion formula to Tanita data and application of the Medas assessment algorithm, the 'converted' Tanita FM estimates closely matched the Medas original estimates (median difference -0.1 kg, 95% CI: -0.3, 0.2 kg), with relatively small LoA for the FM difference (-2.3 to 2.1 kg), suggesting potential interchangeability of the ABC-01 'Medas' and Tanita BC-418MA data at the group level.

CONCLUSIONS

Our results support the importance of cross-calibration of BIA instruments for population comparisons and proper data interpretation in clinical and epidemiological studies.

Body fat rather than body mass index is associated with gingivitis - A southern Brazilian cross-sectional study

BACKGROUND

This cross-sectional study aimed to evaluate the association between body mass index (BMI) and body fat with gingivitis in 613 adults of Porto Alegre, Brazil.

METHODS

Individuals with at least four teeth were included in this study. They were identified through a multi-stage probability sampling, considering the city distribution of sex and age. Structured interviews were conducted by trained researchers in order to collect sociodemographic characteristics, behavioral habits, and systemic impaired conditions. Visible plaque and modified gingival index were assessed by a trained and calibrated examiner. Additionally, weight, height, and body fat percentage were measured. Body fat percentage was determined by bioelectrical-impedance analysis using a portable electrical micro-current monitor. The median sites with marginal bleeding was 20%, and used as a cutoff point for gingivitis. Crude and adjusted prevalence ratio by mean Poisson regression with robust variance were calculated. Two multivariable models were performed in order to associate both independent and dependent variables.

RESULTS

In the multivariable analysis that included BMI, no significant association with gingivitis was detected. On the other hand, the multivariable model that included body fat showed that very high body fat category (PR 1.22; 95% CI: 1.01 to 1.49) was significantly associated with higher marginal gingival bleeding.

CONCLUSION

Very high body fat category rather than BMI was significantly associated with higher positive marginal gingival bleeding in adults.

Increased lipogenesis in spite of upregulated hepatic 5'AMP-activated protein kinase in human non-alcoholic fatty liver

AIMS

Molecular adaptations in human non-alcoholic fatty liver disease (NAFLD) are incompletely understood. This study investigated the main gene categories related to hepatic de novo lipogenesis and lipid oxidation capacity.

METHODS

Liver specimens of 48 subjects were histologically classified according to steatosis severity. In-depth analyses were undertaken using real-time polymerase chain reaction, immunoblotting, and immunohistochemistry. Lipid profiles were analyzed by gas chromatography/flame ionization detection, and effects of key fatty acids were studied in primary human hepatocytes.

RESULTS

Real-time polymerase chain reaction, immunoblotting, and immunohistochemistry indicated 5'AMP-activated protein kinase (AMPK) to be increased with steatosis score ≥ 2 (all P < 0.05), including various markers of de novo lipogenesis and lipid degradation (all P < 0.05). Regarding endoplasmic reticulum stress, X-Box binding protein-1 (XBP1) was upregulated in steatosis score ≥ 2 (P = 0.029) and correlated with plasma palmitate (r = 0.34; P = 0.035). Palmitate incubation of primary human hepatocytes increased XBP1 and downstream stearoyl CoA desaturase-1 mRNA expression (both P < 0.05). Moreover, plasma and liver tissue exposed a NAFLD-related lipid profile with reduced polyunsaturated/saturated fatty acid ratio, increased palmitate and palmitoleate, and elevated lipogenesis and desaturation indices with steatosis score ≥ 2 (all P < 0.05).

CONCLUSION

In humans with advanced fatty liver disease, hepatic AMPK protein is upregulated, potentially in a compensatory manner. Moreover, pathways of lipid synthesis and degradation are co-activated in subjects with advanced steatosis. Palmitate may drive lipogenesis by activating XBP1-mediated endoplasmic reticulum stress and represent a target for future dietary or pharmacological intervention.

Effect of BMI, Body Fat Percentage and Fat Free Mass on Maximal Oxygen Consumption in Healthy Young Adults

INTRODUCTION

Maximal oxygen consumption (VO_2max) is an important measure of cardiorespiratory capacity of an individual at a given degree of fitness and oxygen availability. Risk of cardiovascular diseases increases with increasing degree of obesity and a low level of VO_2max has been established as an independent risk factor for cardiovascular mortality.

AIM

To determine VO_2max in young adults and to find its correlation with Body Mass Index (BMI), Body Fat% and Fat Free Mass (FFM).

MATERIALS AND METHODS

Fifty four (male=30, female=24) healthy young adults of age group18-25 years after screening by Physical Activity Readiness Questionnaire (PAR-Q) participated in the study. Height was measured by stadiometer. Weight was measured by digital weighing scale with 0.1 kg sensitivity. Body fat% was measured by Bioelectrical Impedance Analysis (BIA) method. FFM was calculated by subtracting fat mass from the body weight. VO_2max (mL.kg^-1.min^-1) was obtained by Submaximal Exercise Test (SET) by first two stages of Bruce Protocol with the basis of linear relationship between Heart Rate (HR) and oxygen consumption (VO₂). Data were analysed statistically in GraphPad Prism software version 6.01 for windows.

RESULTS

VO_2max (mL.kg^-1.min^-1) of male (43.25±7.25) was significantly (p<0.001) higher than female (31.65±2.10). BMI showed weak negative correlation (r= -0.3232, p=0.0171) with VO_2max but Body Fat% showed strong negative correlation (r= -0.7505, p<0.001) with VO_2max. FFM positively correlated (r=0.3727, p=0.0055) with VO_2max.

CONCLUSION

Increased body fat is associated with decreased level of VO_2max in young adults. Obesity in terms of Fat% is a better parameter than BMI for prediction of low VO_2max.

The effects of supervised exercise training 12-24 months after bariatric surgery on physical function and body composition: a randomised controlled trial

BACKGROUND

Bariatric surgery is effective for the treatment of stage II and III obesity and its related diseases, although increasing evidence is showing weight regain ~12-24 months postsurgery. Weight regain increases the risk of physical function decline, which negatively affects an individual's ability to undertake activities of daily living. The study assessed the effects of a 12-week supervised exercise intervention on physical function and body composition in patients between 12 and 24 months post bariatric surgery.

METHODS

Twenty-four inactive adult bariatric surgery patients whose body mass index remained ⩾30 kg m² 12 to 24 months post surgery were randomised to an exercise intervention (n=12) or control group (n=12). Supervised exercise consisted of three 60-min gym sessions per week of moderate intensity aerobic and resistance training for 12 weeks. Control participants received usual care. The incremental shuttle walk test (ISWT) was used to assess functional walking performance after the 12-week exercise intervention, and at 24 weeks follow-up. Measures of anthropometric, physical activity, cardiovascular and psychological outcomes were also examined. Using an intention-to-treat protocol, independent t-tests were used to compare outcome measures between groups.

RESULTS

Significant improvements in the exercise group were observed for the ISWT, body composition, physical function, cardiovascular and self-efficacy measures from baseline to 12 weeks. A large baseline to 12-week change was observed for the ISWT (exercise: 325.00±117.28 m; control: 355.00±80.62 m, P<0.001). The exercise group at 24 weeks recorded an overall mean improvement of 143.3±86.6 m and the control group recorded a reduction of -32.50±75.93 m. Findings show a 5.6 kg difference between groups in body mass change from baseline to 24 weeks favouring the exercise group.

CONCLUSIONS

A 12-week supervised exercise intervention led to significant improvements in body mass and functional walking ability post intervention, with further improvements at the 24-week follow-up.

Sociodemographic, Behavioral, and Psychological Correlates of Current Overweight and Obesity in Older, Urban African American Women

To better understand obesity and overweight among urban African American women, the authors examined sociodemographic, behavioral, and psychological factors within body mass index (BMI) categories. A total of 496 women were recruited for cardiovascular risk factor screening from 20 urban African American churches. Study participants had a mean age of 52.8 years, 13.5 years of education, and an average BMI of 32 kg/m2. Bivariate analyses showed increased overall energy intake and decreased physical performance on a walk test, and general well-being declined as the BMI class increased; obese women had the lowest physical performance and well-being levels and the highest energy intake levels. There was no difference by BMI category, however, in social variables such as educational attainment, employment, marital status, or household income. This study suggests that although women with increasing BMI have some physical and well-being concerns, the major social variables are not differentially distributed by BMI in this sample of women.

Cardiopulmonary fitness, adiponectin, chemerin associated fasting insulin level in colorectal cancer patients

PURPOSE

Since circulating level of insulin is associated with colorectal cancer prognosis, it is important to identify factors contributing to fasting insulin level in colorectal cancer patients. The purpose of the current study is to investigate the association of physical fitness, adiponectin, and chemerin levels with circulating level of insulin in colorectal cancer patients.

METHODS

A total of 123 stage II-III colorectal cancer patients who completed standard cancer treatment were recruited. Anthropometric characteristics, fitness measurements, fasting insulin level, homeostasis model assessment of insulin resistance, lipid profiles, and adiponectin and chemerin levels were analyzed.

RESULT

Cardiopulmonary fitness level inversely associated with fasting insulin levels (the least fit (1st tertile): 8.11 ± 0.64, moderately fit (2nd tertile): 6.02 ± 0.63, and highly fit (3rd tertile): 5.58 ± 0.66 μU/ml, unfit vs. moderately fit, p < 0.01; unfit vs. highly fit, p < 0.05) after adjustment for gender, age, stage, and BMI. In addition, fasting adiponectin and chemerin levels were associated with fasting insulin levels after adjustment for gender, age, stage, and BMI. In our combined analyses, participants with high adiponectin and low chemerin levels showed significantly lower fasting insulin levels (4.92 ± 0.75 vs. 8.07 ± 0.80 μU/ml, p < 0.01) compared with participants with low adiponectin and high chemerin levels. Multiple linear regression analysis confirmed that cardiopulmonary fitness and adiponectin levels (β = -0.299, p = 0.002; β = -0.201, p = 0.033) were independently associated with fasting insulin level.

CONCLUSION

Our results suggest that physical fitness and adiponectin and chemerin levels may contribute to circulating levels of insulin. These results suggest that exercise may influence the prognosis of colorectal cancer patients by influencing physical fitness level, circulating levels of adiponectin and chemerin.

Measuring body composition using the bioelectrical impedance method can predict the outcomes of gemcitabine-based chemotherapy in patients with pancreatobiliary tract cancer

In order to examine the effect on body composition of anticancer drug treatments, the body composition rate in patients being treated with gemcitabine (GEM)-based chemotherapy was measured over time on an outpatient basis with a simple body composition monitor using the bioelectrical impedance (BI) method. The results revealed a significant reduction in the body fat rate (P=0.01) over the course of treatment in patients with pancreatobiliary tract cancer who became unable to continue GEM-based chemotherapy due to progressive disease or a decreased performance status. Meanwhile, no changes were observed in the body composition of control patients with urothelial carcinoma receiving GEM-based chemotherapy. In association with the adverse reactions to GEM and the hematotoxicity profile, a decreased white blood cell count was more likely to occur in body fat-dominant patients (mean fat rate, 25.8%; mean muscle rate, 26.2%), whereas a decreased blood platelet count was more likely to occur in skeletal muscle-dominant patients (mean fat rate, 23.3%; mean muscle rates, 28.7%). The correlation between body composition parameters and the relative dose intensity (RDI) associated with GEM administration was also analyzed. The results revealed a positive correlation between the RDI and basal metabolism amount (P=0.03); however, the RDI did not correlate with the body fat rate, skeletal muscle rate or body mass index (P=0.61, P=0.14 and P=0.20, respectively). In conclusion, the body composition rate measurement using the BI method over time may be useful for predicting the outcome of GEM-based chemotherapy and adverse events in patients with pancreatobiliary tract cancer. In particular, the present findings indicate that the changes in body fat rate may be helpful as an adjunct index for assessing potential continuation of chemotherapy and changes in physical conditions.

Energy and macronutrient intake after gastric bypass for morbid obesity: a 3-y observational study focused on protein consumption

BACKGROUND

The effect of a Roux-en-Y gastric bypass (RYGB) on body weight has been amply documented, but few studies have simultaneously assessed the evolution of energy and macronutrient intakes, energy expenditure, and changes in body composition over time after an RYGB.

OBJECTIVE

We evaluated energy and macronutrient intakes, body composition, and the basal metabolic rate (BMR) in obese female patients during the initial 3 y after an RYGB.

METHODS

Sixteen women with a mean ± SEM body mass index (in kg/m(2)) of 44.1 ± 1.6 were included in this prospective observational study. The women were studied on 6 different occasions as follows: before and 1, 3, 6, 12 (n = 16), and 36 (n = 8) mo after surgery. On each occasion, food intake was evaluated from 4- or 7-d dietary records, body composition was assessed with the use of bio-impedancemetry, and energy expenditure was measured with the use of indirect calorimetry.

RESULTS

Body weight evolution showed the typical pattern reported after an RYGB. Total energy intake was 2072 ± 108 kcal/d at baseline and decreased to 681 ± 58 kcal/d at 1 mo after surgery (P < 0.05 compared with at baseline). Total energy intake progressively increased to reach 1240 ± 87 kcal/d at 12 mo after surgery (P < 0.05 compared with at 1 mo after surgery) and 1448 ± 57 kcal/d at 36 mo after surgery (P < 0.05 compared with at 12 mo after surgery). Protein intake was 87 ± 4 g/d at baseline and ± 2 g/d 1 mo after surgery (P < 0.05 compared with at baseline) and increased progressively thereafter to reach 57 ± 3 g/d at 36 mo after surgery (P < 0.05 compared with at 1 mo after surgery). Carbohydrate and fat intakes over time showed similar patterns. Protein intake from meat and cheese were significantly reduced early at 1 mo after surgery but increased thereafter (P < 0.05). The BMR decreased from 1.12 ± 0.04 kcal/min at baseline to 0.93 ± 0.03, 0.86 ± 0.03, and 0.85 ± 0.04 kcal/min at 3, 12, and 36 mo after surgery, respectively (all P < 0.05 compared with at baseline).

CONCLUSIONS

Total energy, carbohydrate, fat, and protein intakes decreased markedly during the initial 1-3 mo after an RYGB, whereas the BMR moderately decreased. The reduction in protein intake was particularly severe at 1 mo after surgery, and protein intake increased gradually after 3-6 mo after surgery. This trial was registered at clinicaltrials.gov as NCT01891591.

Validity of bioelectrical impedance analysis for measuring changes in body water and percent fat after bariatric surgery

BACKGROUND

Few studies have validated bioelectrical impedance analysis (BIA) following bariatric surgery.

METHODS

We examined agreement of BIA (Tanita 310) measures of total body water (TBW) and percent body fat (%fat) before (T0) and 12 months (T12) after bariatric surgery, and change between T0 and T12 with reference measures: deuterium oxide dilution for TBW and three-compartment model (3C) for %fat in a subset of participants (n = 50) of the Longitudinal Assessment of Bariatric Surgery-2.

RESULTS

T0 to T12 median (IQR) change in deuterium TBW and 3C %fat was -6.4 L (6.4 L) and -14.8% (13.4%), respectively. There were no statistically significant differences between deuterium and BIA determined TBW [median (IQR) difference: T0 -0.1 L (7.1 L), p = 0.75; T12 0.2 L (5.7 L), p = 0.35; Δ 0.35 L(6.3 L), p = 1.0]. Compared with 3C, BIA underestimated %fat at T0 and T12 [T0 -3.3 (5.6), p < 0.001; T12 -1.7 (5.2), p = 0.04] but not change [0.7 (8.2), p = 0.38]. Except for %fat change, Bland-Altman plots indicated no proportional bias. However, 95% limits of agreement were wide (TBW 15-22 L, %fat 19-20%).

CONCLUSIONS

BIA may be appropriate for evaluating group level response among severely obese adults. However, clinically meaningful differences in the accuracy of BIA between individuals exist.

Protein and glucose metabolic responses to hyperinsulinemia, hyperglycemia, and hyperaminoacidemia in obese men

OBJECTIVE

In insulin-resistant states, resistance of protein anabolism occurs concurrently with that of glucose, but can be compensated for by abundant amino acid (AA) provision. This effect and its mechanism were sought in obesity.

METHODS

Pancreatic clamps were performed in 8 lean and 11 obese men, following 5-h postabsorptive, 3-h infusions of octreotide, basal glucagon, and growth hormone, with clamped postprandial-level insulin, glucose, and AA. Whole-body [1-(13) C]-leucine and [3-(3) H]-glucose kinetics, skeletal muscle protein ((2) H5 -phenylalanine) fractional synthesis rates, and insulin signaling were determined.

RESULTS

Clamp Δ insulin and Δ branched-chain AA did not differ; fasting glucagon and growth hormone were maintained. Glucose uptake was 20% less in obese concurrent with less Akt(Ser473) , but also less IRS-1(Ser636/639) phosphorylation. Stimulation of whole-body, myofibrillar, and sarcoplasmic protein synthesis was similar. Whole-body protein catabolism suppression tended to be less (P=0.06), resulting in lesser net balance (1.09 ± 0.07 vs. 1.31 ± 0.08 μmol [kg FFM(-1) ] min(-1) , P=0.048). Increments in muscle S6K1(Thr389) phosphorylation were less in the obese, but 4E-BP1(Ser65) did not differ.

CONCLUSIONS

Hyperaminoacidemia with hyperinsulinemia stimulated protein synthesis (possibly via nutrient signaling) normally in obesity, but suppression of proteolysis may be compromised. Whether long-term high protein intakes could compensate for the insulin resistance of protein anabolism remains to be determined.

Food prices and body fatness among youths

We examine the effect of food prices on clinical measures of obesity, including body mass index (BMI) and percentage body fat (PBF) measures derived from bioelectrical impedance analysis (BIA) and dual energy X-ray absorptiometry (DXA), among youths ages 12 through 18 in the National Health and Nutrition Examination Survey. This is the first study to consider clinically measured levels of body composition rather than BMI to investigate the effects of food prices on obesity outcomes among youths classified by gender and race/ethnicity. Our findings suggest that increases in the real price per calorie of food for home consumption and the real price of fast-food restaurant food lead to improvements in obesity outcomes among youths. We also find that a rise in the real price of fruits and vegetables leads to increased obesity. Finally, our results indicate that measures of PBF derived from BIA and DXA are no less sensitive and in some cases more sensitive to the prices just mentioned than BMI, and serve an important role in demonstrating that rising food prices (except fruit and vegetable prices) are indeed associated with reductions in obesity rather than with reductions in body size proportions alone.

A comparison of skinfold thickness, body mass index, bioelectrical impedance analysis and dual-energy X-ray absorptiometry in assessing body composition in obese subjects before and after weight loss

The assessment of body composition in obese subjects by anthropometric means (skinfolds), presents many difficulties. This study compares the estimates provided of fat free mass in 21 obese subjects (mean body mass index 36.6 +/- 1.2 kg/m(2)) using body mass index and skinfold thickness, with those obtained using the more recently developed techniques of bioelectrical impedance analysis and dual-energy X-ray absorptiometry. Despite highly significant correlations between some of the methods (r(2) = 0.94 for dual-energy X-ray absorptiometry versus bioelectrical impedance analysis), there was a considerable lack of agreement in the measurements, particularly when skinfold thickness was compared with dual-energy X-ray absorptiometry (limits of agreement -21.9 to -1.5 kg for fat free mass estimated from dual-energy X-ray absorptiometry and skinfold thickness) and even for dual-energy X-ray absorptiometry and bioelectrical impedance analysis (limits of agreement -10.7 to 0.4 kg). After weight loss the intermethod differences were reduced.

Comparison of Methods to Assess Body Composition Changes during a Period of Weight Loss

OBJECTIVE

To assess the accuracy of body composition measurements by air displacement plethysmography and bioelectrical impedance analysis (BIA) compared with DXA during weight loss.

RESEARCH METHODS AND PROCEDURES

Fifty-six healthy but overweight participants, 34 women and 22 men (age, 52 +/- 8.6 years; weight, 92.2 +/- 11.6 kg; BMI, 33.3 +/- 2.9 kg/m(2)) were studied in an outpatient setting before and after 6 months of weight loss (weight loss, 5.6 +/- 5.5 kg). Subjects were excluded if they had initiated a new drug therapy within 30 days of randomization, were in a weight loss program, or took a weight loss drug within 90 days of randomization. Subjects were randomly assigned either to a self-help program, consisting of two 20-minute sessions with a nutritionist and provision of printed materials and other self-help resources, or to attendance at meetings of a commercial program (Weight Watchers). Body composition was examined by each of the methods before and after weight loss.

RESULTS

BIA (42.4 +/- 5.8%) underestimated percentage fat, whereas the BodPod (Siri = 51.7 +/- 6.9%; Brozek = 48.5 +/- 6.5%) overestimated percentage fat compared with DXA (46.1 +/- 7.9%) before weight loss. Correlation coefficients for detecting changes in body composition between DXA and the other methods were relatively high, with Brozek Deltafat mass (FM; r(2) = 0.63), Siri FM (r(2) = 0.65), tetrapolar BIA percentage fat (r(2) = 0.57), and Tanita FM (r(2) = 0.61) being the highest.

DISCUSSION

In conclusion, all of the methods were relatively accurate for assessing body composition compared with DXA, although there were biases. Furthermore, each of the methods was sensitive enough to detect changes with weight loss.

Human mature adipocytes express albumin and this expression is not regulated by inflammation

AIMS

Our group investigated albumin gene expression in human adipocytes, its regulation by inflammation and the possible contribution of adipose tissue to albumin circulating levels.

METHODS

Both inflamed and healthy subjects provided adipose tissue samples. RT-PCR, Real-Time PCR, and Western Blot analysis on homogenates of adipocytes and pre-adipocytes were performed. In sixty-three healthy subjects and fifty-four micro-inflamed end stage renal disease (ESRD) patients circulating levels of albumin were measured by nephelometry; all subjects were also evaluated for body composition, calculated from bioelectrical measurements and an thropometric data.

RESULTS

A clear gene expression of albumin was showed in pre-adipocytes and, for the first time, in mature adipocytes. Albumin gene expression resulted significantly higher in pre-adipocytes than in adipocytes. No significant difference in albumin gene expression was showed between healthy controls and inflamed patients. A significant negative correlation was observed between albumin levels and fat mass in both healthy subjects and inflamed ESRD patients.

CONCLUSIONS

In the present study we found first time evidence that human adipocytes express albumin. Our results also showed that systemic inflammation does not modulate albumin gene expression. The negative correlation between albumin and fat mass seems to exclude a significant contributing role of adipocyte in plasma albumin.

Birth-weight and resting metabolic rate in adulthood - sex-specific differences

INTRODUCTION

Low birth-weight is associated with an increased risk of cardiovascular disease, hypertension, and the metabolic syndrome (MetS) in adulthood. Resting metabolic rate (RMR) has been suggested to be associated with the development of obesity as well as MetS and might be an indirect indicator of sympathetic activity. This study's aim was to examine the association between birth-weight and adult RMR.

METHODS

A total of 896 men and women from the Helsinki Birth Cohort Study born 1934-44, for whom a detailed set of birth records were available, underwent measurement of body composition and RMR in adulthood.

RESULTS

Among women, birth-weight adjusted for age and fat-free mass (FFM) was inversely associated with RMR (r = -0.12; P < 0.01). For men, a u-shaped relationship was observed, both independently and after adjustment for age, fat mass, and FFM (P = 0.05 for final model).

DISCUSSION

The sex-specific differences for the association between birth-weight and adult RMR might partly be explained by differences in the developmental programming of the sympathetic nervous system between men and women. The higher adjusted RMR among those with the lowest birth-weights is consistent with previous evidence of higher sympathetic drive among these individuals.

The normal range of body mass index with high body fat percentage among male residents of Lucknow city in north India

BACKGROUND & OBJECTIVES

Several studies have raised the suspicion that the body mass index (BMI) cut-off for overweight as defined by the WHO may not adequately reflect the actual overweight status. The present study looked at the relationship between BMI and body fat per cent (BF %) / health risks (hypertension and type 2 diabetes) in male residents of Lucknow city, north India to evaluate the validity of BMI cut-off points for overweight.

METHODS

One thousand one hundred and eleven male volunteer subjects (18-69 yr) who participated in different programmes organized by the Institute during 2005 to 2008 were included in the study. BF% was measured using commercially available digital weight scale incorporating bioelectrical impedance (BI) analyzer. The proposed cut-off for BMI based on BF % was calculated using receiver operating characteristics (ROC) curve analysis.

RESULTS

Forty four per cent subjects showed higher BF % (>25%) with BMI range (24-24.99 kg/m²). Sensitivity and specificity at BMI cut-off at 24.5 kg/m³ were 83.2 and 77.5, respectively. Sensitivity at BMI cut-off >25 kg/m² was reduced by 5 per cent and specificity increased by 4.6 per cent when compared to 24.5 cut-off.

INTERPRETATION & CONCLUSIONS

The study subjects showed higher body fat percentage and risk factors like hypertension and type 2 diabetes at normal BMI range proposed by the WHO. The cut-off for BMI was proposed to be 24.5 kg/m² for our study population. If overweight is regarded as an excess of body fat and not as an excess of weight (increased BMI), the cut-off points for overweight based on BMI would need to be lowered. However, the confidence of estimate of the BMI cut-off in the present study may be considered with the limitations of BI analysis studies.

Dietary phosphate restriction in dialysis patients: a new approach for the treatment of hyperphosphataemia

BACKGROUND AND AIM

Elevated serum phosphate and calcium-phosphate levels play an important role in the pathogenesis of vascular calcifications in uraemic patients and appear to be associated with increased cardiovascular mortality. We aimed to evaluate the effects of a partial replacement of food protein with a low-phosphorus and low-potassium whey protein concentrate on phosphate levels of dialysis patients with hyperphosphataemia.

METHODS AND RESULTS

Twenty-seven patients undergoing chronic haemodialysis were studied for a 3-month period. In the intervention group (n = 15), food protein were replaced by 30 or 40 g of low-phosphorus and low-potassium protein concentrate aimed at limiting the phosphate intake. In the control group (n = 12) no changes were made to their usual diet. Anthropometric measurements, biochemical markers and dietary interviews were registered at baseline and during the follow-up period. From baseline to the end of the study, in the intervention group, serum phosphate and circulating intact parathyroid hormone levels lessened significantly (8.3 ± 1.2 mg/dL vs 5.7 ± 1.4 mg/dL and 488 ± 205 pg/ml vs 177 ± 100 pg/ml respectively; p < 0.05) with decreasing of phosphate and potassium intake. No significant differences were found in the control group. No significant changes were observed in serum albumin, calcium, potassium, Kt/V, body weight and body composition in both the intervention and control groups.

CONCLUSION

Dietary intake of phosphate mainly comes from protein sources, so dietary phosphorus restriction may lead to a protein/energy malnutrition in a dialysis patient. A phosphorus-controlled diet plan including a nutritional substitute resulted in serum phosphate and intact parathyroid hormone decrease without nutritional status modifications in dialysis patients.

Seasonal changes in jump performance and body composition in women volleyball players

The present study aimed to evaluate the effects of different resistance training programs on jump performance and body composition of female volleyball players of the highest Spanish division league over 24 weeks of training. Ten female volleyball players (27.41 ± 4.94 years; 72.2 ± 8.5 kg; 179.7 ± 6.4 cm) completed 24 weeks of training and testing using a linear periodization, progressing from general conditioning (weeks 1-4), to hypertrophy (weeks 5-8), then to maximum strength and power (weeks 9-16) and concluding with a specific strength training (weeks 17-24). Body composition was measured using bioelectrical-impedance analysis, and neuromuscular capacity was estimated by squat jump, countermovement jump, Abalakov jump, and 2 repetition maxima (2RM). After initial evaluation (PRE), the players were tested on 3 different occasions (POST: fourth week, POST 1: eighth week and POST 2: 24th week) of the training cycle. Muscle mass increased on (4.5%, p < 0.05) and fat-free mass (4.38%, p < 0.05), whereas fat percent decreased (13.90%, p < 0.05). All neuromuscular performance tests were increased from PRE to POST 2 (ranging from 17.64 to 20.89%, p < 0.01) and from POST 1 to POST 2 (ranging from 4.62 to 7.56% p < 0.01). The results suggest that the volleyball players studied continued improving power and strength capacity together with body composition during the course of the study. Finally, as major application, these data provide normative and performance standards for female volleyball players.

Estimation of normal hydration in dialysis patients using whole body and calf bioimpedance analysis

Prescription of an appropriate dialysis target weight (dry weight) requires accurate evaluation of the degree of hydration. The aim of this study was to investigate whether a state of normal hydration (DW(cBIS)) as defined by calf bioimpedance spectroscopy (cBIS) and conventional whole body bioimpedance spectroscopy (wBIS) could be characterized in hemodialysis (HD) patients and normal subjects (NS). wBIS and cBIS were performed in 62 NS (33 m/29 f) and 30 HD patients (16 m/14 f) pre- and post-dialysis treatments to measure extracellular resistance and fluid volume (ECV) by the whole body and calf bioimpedance methods. Normalized calf resistivity (ρ(N)(,5)) was defined as resistivity at 5 kHz divided by the body mass index. The ratio of wECV to total body water (wECV/TBW) was calculated. Measurements were made at baseline (BL) and at DW(cBIS) following the progressive reduction of post-HD weight over successive dialysis treatments until the curve of calf extracellular resistance is flattened (stabilization) and the ρ(N)(,5) was in the range of NS. Blood pressures were measured pre- and post-HD treatment. ρ(N)(,5) in males and females differed significantly in NS. In patients, ρ(N)(,5) notably increased with progressive decrease in body weight, and systolic blood pressure significantly decreased pre- and post-HD between BL and DW(cBIS) respectively. Although wECV/TBW decreased between BL and DW(cBIS), the percentage of change in wECV/TBW was significantly less than that in ρ(N)(,5) (-5.21 ± 3.2% versus 28 ± 27%, p < 0.001). This establishes the use of ρ(N)(,5) as a new comparator allowing a clinician to incrementally monitor removal of extracellular fluid from patients over the course of dialysis treatments. The conventional whole body technique using wECV/TBW was less sensitive than the use of ρ(N)(,5) to measure differences in body hydration between BL and DW(cBIS).

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.

Body composition and wages

This paper examines the relationship between body composition and wages in the United States. We develop measures of body composition--body fat (BF) and fat-free mass (FFM)--using data on bioelectrical impedance analysis (BIA) that are available in the National Health and Nutrition Examination Survey III and estimate wage models for respondents in the National Longitudinal Survey of Youth 1979. Previous research uses body size or BMI as measures of obesity despite a growing concern that they do not distinguish between body fat and fat-free body mass or adequately control for non-homogeneity inside the human body. Therefore, measures presented in this paper represent a useful alternative to BMI-based proxies of obesity. Our results indicate that BF is associated with decreased wages for both males and females among whites and blacks. We also present evidence suggesting that FFM is associated with increased wages. We show that these results are not the artifacts of unobserved heterogeneity. Finally, our findings are robust to numerous specification checks and to a large number of alternative BIA prediction equations from which the body composition measures are derived.

A novel bioengineering clinical device testing cellular homeostatic potentials to customize and monitor nutritional-related age-management interventional strategies

Most devices assessing body composition harbor a number of drawbacks and hardly assess the phenomena taking place at a cellular membrane level. The present single-frequency bioelectrical potential homeostatic structure analysis (PHoSA) technology requires only a proper hands contact on fixed electrodes and determines the phase displacement between tested current and voltage by using a 50-KHz alternate sinusoidal current. This allows quick testing time with high degree of precision, sensitivity, and specificity of sectorial functional body compartments analysis. Such assessment may prove to be an integrated part of either a diagnostic workup or monitoring tool in tailoring nutritional/nutraceutical, pharmacological, and exercise activity, all being framed within a proactive, preventive, age-intervention management strategy.

Metabolic parameters after BioEnterics Intragastric Balloon placement in obese patients

BACKGROUND

BioEnterics Intragastric Balloon (BIB) is a non-invasive, temporary and relatively safe procedure shown to be effective in the short-term treatment of obesity. Nowadays, BIB does not show convincing evidence of significant long-term weight loss, as compared with conventional management, and data regarding changes in metabolic and nutritional parameters are lacking.

METHODS

Forty obese patients [11 males, 29 females, age 36.65+/-10.6 yr, body mass index (BMI) 44.9+/-8.9 kg/m2] were evaluated before and 3 and 6 months after BIB placement by assessment of anthropometric and biochemical parameters as well as nutritional habits.

RESULTS

Patients showed a significant reduction in weight (-13.2+/-6.5%), BMI (-13.2%), waist circumference (-6.5 cm), and percentage of fat mass (-19.5%), but not fat-free mass. A significant improvement in insulin sensitivity but not in lipid pattern was seen. After BIB insertion, a significant reduction in caloric intake was paralleled by a redistribution of nutrients; in particular, increased lipid (12.8%) and decreased carbohydrate (-11.7%) percentage, but not absolute intake was observed.

CONCLUSION

These data show that BIB improves anthropometric parameters, with reduction of fat mass and preservation of fat-free mass, as well as insulin resistance, but not other metabolic features. The observed change in dietary habits, with a relative increase in lipid intake, once BIB is removed, might favor body weight regain and impact negatively on body weight composition and the other traits of the metabolic syndrome.

Body composition methods: comparisons and interpretation

The incidence of obesity in the United States and other developed countries is epidemic. Because the prevalence of comorbidities to obesity, such as type 2 diabetes, has also increased, it is clear there is a great need to monitor and treat obesity and its comorbidities. Body composition assessments vary in precision and in the target tissue of interest. The most common assessments are anthropometric and include weight, stature, abdominal circumference, and skinfold measurements. More complex methods include bioelectrical impedance, dual-energy X-ray absorptiometry, body density, and total body water estimates. There is no single universally recommended method for body composition assessment in the obese, but each modality has benefits and drawbacks. We present here the most common methods and provide guidelines by way of examples to assist the clinician/researcher in choosing methods appropriate to their situation.

Body composition analysis by leg-to-leg bioelectrical impedance and dual-energy X-ray absorptiometry in non-obese and obese individuals

AIM

The aim of this study is to compare total weight, % body fat (% BF), fat mass (FM) and fat-free mass (FFM) measured by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA).

METHODS

This cross-sectional study included 159 women (mean age: 49.1 +/- 10.0 years) and 124 men (mean age: 51.4 +/- 8.0 years) subdivided according to sex and body mass index (BMI): BMI < 30 kg/m(2) (66 women and 50 men); BMI 30-35 kg/m(2) (53 women and 44 men) and BMI > or = 35 kg/m(2) (40 women and 30 men). Bioelectrical impedance was performed in the fasting state on a Tanita TBF-215 leg-to-leg analyser (Tanita, Tokyo, Japan). Whole-body DXA scans were performed on a Hologic QDR 4500 A bone densitometer (Hologic, Bedford, MA, USA). Total weight, % BF, FM and FFM were tested for intermethod differences. Linear regression and correlation analysis was performed. Limits of agreement and Bland-Altman plots were built.

RESULTS

DXA-derived body composition parameters were not significantly different from BIA estimates and were highly correlated (e.g. for FFM, r = 0.82-0.95). In lean individuals, BIA tended to produce lower values for FM and % BF and higher ones for FFM in comparison with DXA. This trend was reversed at BMI > 35 kg/m(2). The correlations decreased with increasing BMI. The limits of agreement were much better in men than in women and increased with increasing BMI in both sexes.

CONCLUSIONS

Compared with DXA, the leg-to-leg Tanita TBF-215 analyser accurately assessed body composition in a heterogeneous group of both sexes. In the very obese women (BMI > 35 kg/m(2)), BIA measurements should be viewed with caution.