Body composition measurement in severe obesity

Body composition assessment in individuals with class II/III obesity: a narrative review

BACKGROUND

Individuals with class II/III obesity have a high percentage of body fat. Assessing body composition in cases of severe obesity can be difficult and controversial both in clinical practice and scientific research. Thus, it is essential to explore the different aspects of evaluating body composition and to discuss the available methods to assess it in this population.

AIMS

To summarise and discuss the methods used to measure body composition in adults with class II/III obesity and their potential in clinical practice and scientific research.

METHODS

This is a narrative review using data from PubMed, Scielo, and Lilacs databases. Original articles on body composition analysis in adults with class II/III obesity i.e., a BMI ≥ 35 kg/m2 were eligible. Body composition assessment methods were analysed and described.

RESULTS

Some imaging methods produced significantly accurate results. Dual-energy X-ray absorptiometry (DXA) significantly produces accurate results and has been used in clinical studies. However, due to its high cost, it is not applicable in clinical practice. Multifrequency bioelectrical impedance analysis (BIA) has good accuracy and is more appropriate for clinical practice than other methods. We have highlighted several aspects of the importance and applicability of performing body composition analysis in individuals with class II/III obesity.

CONCLUSION

DXA has been considered the most adequate method for clinical research. Multifrequency BIA may be a viable alternative to DXA for use in clinical practice. Assessing body composition and its components is important for people with class II/III obesity. It can help improve the effectiveness of interventions and clinical treatments, especially in reducing the risk of losing muscle mass. Muscle loss can cause sarcopenic obesity and other clinical complications, so understanding body composition is crucial. Assessing body composition can also help understand the impact of interventions on bones and avoid clinical complications.

Agreement between equation-derived body fat estimator and bioelectrical impedance analysis for body fat measurement in middle-aged southern Indians

Excess body fat (BF) contributes to metabolic syndrome (MetS). The Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE) is an equation-derived body fat estimator proposed to assess BF. However, its efficiency compared to the standard method is unknown. We aimed to compare the efficacy of CUN-BAE with the standard method in estimating BF in southern Indians. We included 351 subjects, with 166 MetS patients and 185 non-MetS subjects. BF was obtained from the standard bioelectrical impedance analysis (BIA) method and measured by CUN-BAE in the same subjects. We compared the efficacy of CUN-BAE in estimating BF with that of BIA via Bland-Altman plots, intraclass correlation coefficients, concordance correlation coefficients and the kappa index. The mean body fat percentage (BF%) values measured by BIA and CUN-BAE in all the subjects were 28.91 ± 8.94 and 29.22 ± 8.63, respectively. We observed significant absolute agreement between CUN-BAE and BIA for BF%. BIA and CUN-BAE showed good reproducibility for BF%. CUN-BAE had accuracy comparable to BIA for detecting MetS using BF%. Our findings indicate that CUN-BAE provides precise BF estimates similar to the BIA method, making it suitable for routine clinical practice when access to BF measurement devices is limited.

Prediction of whole body composition utilizing cross-sectional abdominal imaging in pediatrics

BACKGROUND

Although body composition is an important determinant of pediatric health outcomes, we lack tools to routinely assess it in clinical practice. We define models to predict whole-body skeletal muscle and fat composition, as measured by dual X-ray absorptiometry (DXA) or whole-body magnetic resonance imaging (MRI), in pediatric oncology and healthy pediatric cohorts, respectively.

METHODS

Pediatric oncology patients (≥5 to ≤18 years) undergoing an abdominal CT were prospectively recruited for a concurrent study DXA scan. Cross-sectional areas of skeletal muscle and total adipose tissue at each lumbar vertebral level (L1-L5) were quantified and optimal linear regression models were defined. Whole body and cross-sectional MRI data from a previously recruited cohort of healthy children (≥5 to ≤18 years) was analyzed separately.

RESULTS

Eighty pediatric oncology patients (57% male; age range 5.1-18.4 y) were included. Cross-sectional areas of skeletal muscle and total adipose tissue at lumbar vertebral levels (L1-L5) were correlated with whole-body lean soft tissue mass (LSTM) (R²= 0.896-0.940) and fat mass (FM) (R²= 0.874-0.936) (p < 0.001). Linear regression models were improved by the addition of height for prediction of LSTM (adjusted R² = 0.946-0^.971; p < 0.001) and by the addition of height and sex (adjusted R² = 0.930-0.953) (p < 0^.001)) for prediction of whole body FM. High correlation between lumbar cross-sectional tissue areas and whole-body volumes of skeletal muscle and fat, as measured by whole-body MRI, was confirmed in an independent cohort of 73 healthy children.

CONCLUSION

Regression models can predict whole-body skeletal muscle and fat in pediatric patients utilizing cross-sectional abdominal images.

Effect of a ketogenic diet on pain and quality of life in patients with lipedema: The LIPODIET pilot study

Background

Lipedema is an underdiagnosed condition in women, characterized by a symmetrical increase in subcutaneous adipose tissue (SAT) in the lower extremities, sparing the trunk. The lipedema SAT has been found to be resistant to diet, exercise and bariatric surgery, in regard to both weight loss (WL) and symptom relief. Current experience indicates that a low carbohydrate and high fat (LCHF-diet) might have a beneficial effect on weight and symptom management in lipedema.

Objective

To assess the impact of an eucaloric low carbohydrate, high fat (LCHF)-diet on pain and quality of life (QoL) in patients with lipedema.

Methods

Women diagnosed with lipedema, including all types and stages affecting the legs, (age 18-75 years, BMI 30-45 kg/m2) underwent 7 weeks of LCHF-diet and, thereafter 6 weeks of a diet following the Nordic nutrition recommendations. Pain (visual analog scale) and QoL (questionnaire for lymphedema of the limbs), weight and body composition were measured at baseline, week seven and 13.

Results

Nine women (BMI: 36.7 ± 4.5 kg/m2 and age: 46.9 ± 7 years) were recruited. The LCHF diet induced a significant WL -4.6 ± 0.7 kg (-4.5 ± 2.4%), p < 0.001 for both, and reduction in pain (-2.3 ± 0.4 cm, p = 0.020). No correlation was found between WL and changes in pain at week seven (r = 0.283, p = 0.460). WL was maintained between week seven and 13 (0.3 ± 0.7 kg, p = 0.430), but pain returned to baseline levels at week 13 (4.2 ± 0.7 cm, p = 0.690). A significant increase in general QoL was found between baseline and week seven (1.0 (95% CI (2.0, 0.001)), p = 0.050) and 13 (1.0 95% CI (2.0, 0.001) p = 0.050), respectively.

Conclusion

A LCHF-diet is associated with reduction in perceived pain and improvement in QoL, in patients with lipedema. Larger randomized clinical trials are needed to confirm these findings.

Pharmacokinetic Evaluation of Intravenous Vitamin C: A Classic Pharmacokinetic Study

PURPOSE

Intravenous vitamin C (IVC) is used in a variety of disorders with limited supporting pharmacokinetic data. Herein we report a pharmacokinetic study in healthy volunteers and cancer participants with IVC doses in the range of 1-100 g.

METHODS

A pharmacokinetic study was conducted in 21 healthy volunteers and 12 oncology participants. Healthy participants received IVC infusions of 1-100 g; oncology participants received IVC infusions of 25-100 g. Serial blood and complete urine samples were collected pre-infusion and for 24 h post-infusion. Pharmacokinetic parameters were computed using noncompartmental methods. Adverse events were monitored during the study.

RESULTS

In both cohorts, IVC exhibited first-order kinetics at doses up to 75 g. At 100 g, maximum concentration (C_max) plateaued in both groups, whereas area under the concentration-time curve (AUC) only plateaued in the healthy group. IVC was primarily excreted through urine. No saturation of clearance was observed; however, the mean 24-h total IVC excretion in urine for all doses was lower in oncology participants (89% of dose) than in healthy participants at 100 g (99%). No significant adverse events were observed; thus, maximum tolerated dose (MTD) was not reached.

CONCLUSION

IVC followed first-order pharmacokinetics up to 75 g and at up to 100 g had complete renal clearance in 24 h. IVC up to 100 g elicited no adverse effects or significant physiological/biochemical changes and appears to be safe. These data can be used to rectify existing misinformation and to guide future clinical trials.

REGISTRATION

ClinicalTrials.gov identifier number NCT01833351.

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Identification of Adolescents with Adiposities and Elevated Blood Pressure and Implementation of Preventive Measures Warrants the Use of Multiple Clinical Assessment Tools

The burden of abdominal adiposity has increased globally, which is recognized as a key condition for the development of obesity-related disorders among youth, including type 2 diabetes, cardiovascular disease, and hypertension. High blood pressure (BP) and cardiovascular diseases increase the rates of premature mortality and morbidity substantially. Aims: to investigate the relation between abdominal adiposity and elevated BP among adolescent males in Jordan. Methods: Nationally representative sample of male adolescents was selected using multi-cluster sampling technique. Study sample included 1035 adolescent males aged 12 to 17 years. Multiple indicators were used to assess adiposity including waist circumference (WC) and total body fat (TF), truncal fat (TrF), and visceral fat (VF). Systolic blood pressure was measured to assess hypertension. Results: After adjusting for age, smoking status, and physical activity, the odds of having stage two hypertension increased 6, 7, and 8 times for adolescents who were on 90th percentile or above for Trf, VF, and WC, respectively. Conclusion: Elevated BP was significantly associated with total and abdominal adiposity among adolescent males in Jordan. Use of multiple clinical assessment tools is essential to assess abdominal obesity among adolescents.

Association of Body Composition and Sarcopenia with NASH in Obese Patients

Obese patients often suffer from sarcopenia or sarcopenic obesity (SO) that can trigger inflammatory diseases including non-alcoholic steatohepatitis (NASH). Sarcopenia and SO can be diagnosed through measuring parameters of body composition such as skeletal muscle mass (SMM), skeletal muscle index (SMI) and fat mass (FM) obtained by bioelectrical impedance analysis (BIA). The aim of this study was to assess the relationship of body composition and NASH in patients with obesity. A total of 138 patients with obesity that underwent bariatric surgery were included in this study. BIA was used to estimate body composition. A liver biopsy was taken intraoperatively and histological assessment of NASH was performed. A total of 23 patients (17%) were classified as NASH and 65 patients (47%) met the criteria for borderline NASH. Body mass index (BMI) was significantly higher in patients with NASH compared to borderline NASH and no NASH (56.3 kg/m² vs. 51.6 kg/m² vs. 48.6 kg/m², p = 0.004). Concerning body composition, FM, but also SMM and SMI were significantly higher in patients with NASH (p-values 0.011, 0.005 and 0.006, resp.). Fat mass index (FMI) and weight-adjusted skeletal muscle index (SMI_weight) failed to reach statistical significance (p-values 0.067 and 0.661). In patients with obesity, higher FM were associated with NASH. Contrary to expectations, SMM and SMI were also higher in patients with NASH. Therefore, higher body fat, rather than sarcopenia and SO, might be decisive for development of NASH in patients with obesity.

Antineoplastic dosing in overweight and obese cancer patients: an Associazione Italiana Oncologia Medica (AIOM)/Associazione Medici Diabetologi (AMD)/Società Italiana Endocrinologia (SIE)/Società Italiana Farmacologia (SIF) multidisciplinary consensus position paper

Most anticancer molecules are administered in body-size-based dosing schedules, bringing up unsolved issues regarding pharmacokinetic data in heavy patients. The worldwide spread of obesity has not been matched by improved methods and strategies for tailored drug dosage in this population. The weight or body surface area (BSA)-based approaches may fail to fully reflect the complexity of the anthropometric features besides obesity in cancer patients suffering from sarcopenia. Likewise, there is a lack of pharmacokinetic data on obese patients for the majority of chemotherapeutic agents as well as for new target drugs and immunotherapy. Therefore, although the available findings point to the role of dose intensity in cancer treatment, and support full weight-based dosing, empirical dose capping often occurs in clinical practice in order to avoid toxicity. Thus a panel of experts of the Associazione Italiana Oncologia Medica (AIOM), Associazione Medici Diabetologi (AMD), Società Italiana Endocrinologia (SIE), and Società Italiana Farmacologia (SIF), provides here a consensus statement for appropriate cytotoxic chemotherapy and new biological cancer drug dosing in obese patients.

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The worldwide spread of obesity is an emerging challenge also in cancer patients

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Weight or BSA-based approaches do not adequately address the critical issue of optimal dosing for cancer drugs under obesity

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Empirical dose capping is often employed in clinical practice to avoid toxicities among overweight and obese patients

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There is a lack of clinical and pharmacokinetic studies in this population

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Clinical practice recommendations should guide suitable dosing of cytotoxic and biological cancer drugs in obese patients

Strength and Performance Tests for Screening Reduced Muscle Mass in Elderly Lebanese Males with Obesity in Community Dwellings

The reduction in skeletal muscle mass (SMM) is a common phenomenon in older adults. It is associated with several diseases, a reduction in physical fitness, longer periods of hospitalization and high rates of mortality. We aimed to identify the reliability of simple tools for screening for reduced SMM among older adult males in Lebanon. The Tanita MC-780MA bioimpedance analyzer (BIA) was used to assess body composition in a population of 102 community-dwelling elderly males with overweight or obesity, in order to be then categorized as with or without reduced SMM. Participants also performed the handgrip strength test and the 4 m gait speed test. Of the total sample of 102 participants (mean age 67.4 ± 6.96 years; BMI 30.8 6 ± 4.04 kg/m²), 32 (31.4%) met the criteria for reduced SMM. Partial correlation analysis showed that handgrip strength (ρ = 0.308, p = 0.002) and 4 m gait speed (ρ = 0.284, p = 0.004) were both associated with low SMM. Receiver operating characteristic (ROC) curve analysis identified discriminating cut-off points of 1.1 m/s for the 4 m gait speed test and 32.0 kg for the handgrip strength test. Our study showed that participants displayed a substantial prevalence of reduced SMM. Reduced 4 m gait speed and handgrip strength were associated with low SMM. Clear cut-off points for strength and functional tests for screening for this condition in Lebanese older men were identified.

[Body composition assessment before and after weight loss following a Roux-en-Y gastric bypass. Are bioimpedanciometry estimations reliable?]

Introduction

Introduction: in patients with severe and morbid obesity it has been observed that bioimpedance (BIA) assessment generates an underestimation of fat mass (FM) and weight loss as FM after bariatric surgery, overestimating the loss of fat-free mass (FFM) and muscle mass. Objective: to evaluate the reliability of bioelectrical impedance analysis (BIA) to estimate total body water (TBW), fat-free mass (FFM), fat mass (FM), and its changes after 6 months of a Roux-en-Y gastric bypass (RYGBP), in patients with severe and morbid obesity. Methods: thirty-six patients approved for RYGBP were prospectively studied. TBW was measured by deuterium (D), and FM and FFM were calculated. A dual-frequency BIA device (5 and 200 kHz) (Bodystat Dualscan®) was used to estimate FM, FFM, TBW, extracellular water (ECW), intracellular water (ICW), and ECW/ICW ratio. Results: before RYGBP, BIA overestimated TBW by 2.6 ± 4.3 L (p = 0.002) and FFM by 3.5 ± 5.7 kg (p = 0.002), and underestimated FM% by 2.98 ± 4.7% (p = 0.002). The ECW/ICW ratio showed a significant and positive correlation with the difference BIA-D for FFM (r = 0.49; p = 0.002). After surgery, the differences between BIA and D were not significant, and the estimation error of FFM did not correlate with the ECW/ICW ratio. Conclusions: BIA generates an underestimation of FM as reported in patients with severe and morbid obesity, which is attenuated after weight reduction, underestimating weight loss as FM and overestimating FFM loss. Future research may assess whether these errors are reproduced by other BIA devices.

The Effect of Low-Volume High-Intensity Interval Training on Body Composition and Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence for the efficacy of low-volume high-intensity interval training (HIIT) for the modulation of body composition is unclear.

OBJECTIVES

We examined the effect of low-volume HIIT versus a non-exercising control and moderate-intensity continuous training (MICT) on body composition and cardiorespiratory fitness in normal weight, overweight and obese adults. We evaluated the impact of low-volume HIIT (HIIT interventions where the total amount of exercise performed during training was ≤ 500 metabolic equivalent minutes per week [MET-min/week]) compared to a non-exercising control and MICT.

METHODS

A database search was conducted in PubMed (MEDLINE), EMBASE, CINAHL, Web of Science, SPORTDiscus and Scopus from the earliest record to June 2019 for studies (randomised controlled trials and non-randomised controlled trials) with exercise training interventions with a minimum 4-week duration. Meta-analyses were conducted for between-group (low-volume HIIT vs. non-exercising control and low-volume HIIT vs. MICT) comparisons for change in total body fat mass (kg), body fat percentage (%), lean body mass (kg) and cardiorespiratory fitness.

RESULTS

From 11,485 relevant records, 47 studies were included. No difference was found between low-volume HIIT and a non-exercising control on total body fat mass (kg) (effect size [ES]: - 0.129, 95% confidence interval [CI] - 0.468 to 0.210; p = 0.455), body fat (%) (ES: - 0.063, 95% CI - 0.383 to 0.257; p = 0.700) and lean body mass (kg) (ES: 0.050, 95% CI - 0.250 to 0.351; p = 0.744), or between low-volume HIIT and MICT on total body fat mass (kg) (ES: - 0.021, 95% CI - 0.272 to 0.231; p = 0.872), body fat (%) (ES: 0.005, 95% CI - 0.294 to 0.304; p = 0.974) and lean body mass (kg) (ES: 0.030, 95% CI - 0.167 to 0.266; p = 0.768). However, low-volume HIIT significantly improved cardiorespiratory fitness compared with a non-exercising control (p < 0.001) and MICT (p = 0.017).

CONCLUSION

These data suggest that low-volume HIIT is inefficient for the modulation of total body fat mass or total body fat percentage in comparison with a non-exercise control and MICT. A novel finding of our meta-analysis was that there appears to be no significant effect of low-volume HIIT on lean body mass when compared with a non-exercising control, and while most studies tended to favour improvement in lean body mass with low-volume HIIT versus MICT, this was not significant. However, despite its lower training volume, low-volume HIIT induces greater improvements in cardiorespiratory fitness than a non-exercising control and MICT in normal weight, overweight and obese adults. Low-volume HIIT, therefore, appears to be a time-efficient treatment for increasing fitness, but not for the improvement of body composition.

Cold-Activated Brown Adipose Tissue is Associated with Less Cardiometabolic Dysfunction in Young Adults with Obesity

OBJECTIVE

This study aimed to test the hypothesis that young adults with obesity and cold-activated brown adipose tissue (BAT) are less likely to have metabolic dysfunction (dyslipidemia, insulin resistance, and hypertension) than those without cold-activated BAT. Previous studies have noted a potentially protective effect of BAT and higher adiponectin/leptin ratios, but they have acknowledged that the clinical implications of these findings remain uncertain.

METHODS

Twenty-one females and twenty-three males with obesity (BMI ≥ 30 kg/m² ) underwent a 2-hour cooling protocol before ¹⁸ F-fluorodeoxyglucose (¹⁸ F-FDG)-positron emission tomography/x-ray computed tomography scan to determine the prevalence, volume, and ¹⁸ F-FDG uptake of cold-activated BAT.

RESULTS

Cold-activated BAT was identified in 43% of participants (11 female, 8 male); females had greater ¹⁸ F-FDG uptake. Those with cold-activated BAT had a lesser degree of metabolic dysfunction. Cold-activated BAT volume correlated with triglycerides (inversely) and adiponectin (concordantly). Body-mass-adjusted cold-activated BAT activity correlated with high-density lipoprotein cholesterol (concordantly). Males with cold-activated BAT had lower leptin and higher adiponectin/leptin ratio.

CONCLUSIONS

A high prevalence of cold-activated BAT was found in the study participants. BAT could be important in decreasing metabolic dysfunction among young adults with obesity, making it a potential target for treating metabolically unhealthy obesity.

New Predictive Equations for Estimating Resting Energy Expenditure in Adults With Crohn's Disease

BACKGROUND

Increased resting energy expenditure (REE) has been hypothesized to be a potential cause of weight loss in individuals with Crohn's disease (CD). This study aimed to develop and validate new predictive equations for estimating REE in adults with CD.

METHODS

Adults, ages 18-65 years, with CD were recruited. Anthropometry, indirect calorimetry, and bioimpedance analysis were performed in all patients. Disease activity was assessed by Crohn's Disease Activity Index. The new predictive equations were generated using different regression models. Prediction accuracy of the new equations was assessed and compared with the most commonly used equations.

RESULTS

A total of 270 CD patients (159 males, 111 females) were included and randomly assigned to the calibration (n = 180) and validation groups (n = 90). REE was directly correlated with weight and bioimpedance index, whereas the relation with both age and disease activity was inverse. The new equations were suitable for estimating REE at population level (bias: -0.2 and -0.3, respectively). Individual accuracy was good in both models (≥80%, respectively), especially in females; and similar results were shown by some of the selected equations. But, when accuracy was set within ±5%, the new equations gave the highest prediction.

CONCLUSION

The new, disease-specific, equations for predicting REE in individuals with CD give a good prediction accuracy as far as those proposed in the literature for the general population. However, the new ones performed better at the individual level. Further studies are needed to verify the reliability and usefulness of these new equations.

High Hydration Factor in Older Hispanic-American Adults: Possible Implications for Accurate Body Composition Estimates

Age- and obesity-related body composition changes could influence the hydration factor (HF) and, as a result, body composition estimates derived from hydrometry. The aim of the present study was to compare the HF in older Hispanic-American adults to some published values. This cross-sectional study included a sample of 412 subjects, men and women, aged ≥60 years from northern Mexico. HF values were calculated based on the ratio of total body water-using the deuterium dilution technique-to fat-free mass, derived from the four-compartment model. The mean HF value for the total sample (0.748 ± 0.034) was statistically (p ≤ 0.01) higher than the traditionally assumed value of 0.732 derived from chemical analysis, the "grand mean'' value of 0.725 derived from in vivo methods, and the 0.734 value calculated for older French adults via the three-compartment model. The HF of the older women did not differ across the fat mass index categories, but in men the obese group was lower than the normal and excess fat groups. The hydration factor calculated for the total sample of older Hispanic-American people is higher than the HF values reported in the literature. Therefore, the indiscriminate use of these assumed values could produce inaccurate body composition estimates in older Hispanic-American people.

ADDITIONAL ABDOMINAL MEASUREMENTS ARE A USEFUL TOOL TO EVALUATE BODY COMPOSITION IN OBESE WOMEN

BACKGROUND

During weight gain, most of the excess adipose tissue accumulates in the trunk. This alters the body shape and makes collection of anthropometric measurements, especially waist circumference (WC), difficult.

OBJECTIVE

To evaluate the sensitivity and applicability of additional abdominal measurements in order to assess body composition of obese women.

METHODS

A total of 30 women between 20 and 50 years of age and BMI above 30 kg/m² were assessed. Three WC measurements, were performed: at the umbilical scar designated as WC1 and at 8 and 16 cm above the umbilical scar, designated as WC2, and WC3 respectively. The correlation (r) between these anthropometric measurements and their sum was assessed against the parameters fat mass (FM), free fat mass (FFM), body fat percentage (%BF), and trunk fat percentage (%TF), obtained by total and trunk segmental bioelectric impedance analysis (BIA) as well as by the golden standard total and trunk dual energy X-ray absorptiometry (DXA).

RESULTS

The measurements WC1, WC2, WC3, and their sum correlated strongly and moderately with the parameters FM, FFM, and %BF in total BIA and in both total DXA and trunk DXA.

CONCLUSION

The results demonstrated a robust correlation between the sum of the three WC measurements and total and trunk DXA in obese women suggesting that such measurements may be a good indicator of body and trunk fat in women, actually superior to BIA results. The use of these three measurements may be an alternative for the assessment of body and trunk fat, in those cases in which the body shape due to adipose tissue trunk accumulation makes accurate classical measurement (WC1) difficult.

Visceral fat reduction is positively associated with blood pressure reduction in overweight or obese males but not females: an observational study

BACKGROUND

Visceral adiposity has been reported to play a key role in hypertension compared with other measurements of regional or general obesity. The aim of current study was to evaluate the relationship between visceral fat reduction and changes in blood pressure in a group of overweight or obese Chinese individuals.

METHODS

An observational study was conducted with 168 participants (ChiCTR-OOC-17012000). Body composition, blood parameters and blood pressure were assessed at the beginning and end of the intervention. Males and females were categorized separately into quartiles according to changes in visceral fat during the intervention. Multiple linear regression models were used to assess the associations of changes in systolic and diastolic blood pressure with changes of visceral fat area, adjusted for potential confounders.

RESULTS

Changes in visceral fat was significantly associated with systolic and diastolic blood pressure in men for systolic (β = 0.234, 95% CI: 0.103, 0.365; p = 0.001) and diastolic blood pressure (β = 0.237; 95% CI: 0.127, 0.346; p <0.001), but not in women after adjustment for the same potential confounders for systolic blood (β = - 0.003, 95% CI: - 0.260, 0.255; p = 0.984) and diastolic blood pressure (β = 0.101, 95% CI: - 0.072, 0.273; p = 0.249).

CONCLUSIONS

A positive association was observed between reduction in visceral fat and improvements in both systolic blood and diastolic blood pressures in males but not females in a 12-week meal replacement intervention.

TRIAL REGISTRATION

The Ethics Committee of Peking University Health Science Center approved the study protocol on 6 July 2017. The authors confirm that all ongoing and related trials for this intervention were carried out following the rules of the Declaration of Helsinki of 1975 and registered (ChiCTR-OOC-17012000). http://www.chictr.org.cn/showprojen.aspx?proj=20426.

A swan song for Kt/Vurea

Dialyzer clearance of urea multiplied by dialysis time and normalized for urea distribution volume (Kt/V_urea or simply Kt/V) has been used as an index of dialysis adequacy since more than 30 years. This article reviews the flaws of Kt/V, starting with a lack of proof of concept in three randomized controlled hard outcome trials (RCTs), and continuing with a long list of conditions where the concept of Kt/V was shown to be flawed. This information leaves little room for any conclusion other than that Kt/V, as an indicator of dialysis adequacy, is obsolete. The dialysis patient might benefit more if, instead, the nephrology community concentrates in the future on pursuing the optimal dialysis dose that conforms with adequate quality of life and on factors that are likely to affect outcomes more than Kt/V. These include residual renal function, volume status, dialysis length, ultrafiltration rate, the number of intra-dialytic hypotensive episodes, interdialytic blood pressure, serum potassium and phosphate, serum albumin, and C reactive protein.

Very low-calorie diet in candidates for bariatric surgery: change in body composition during rapid weight loss

OBJECTIVE

To analyze the changes in the body composition of morbidly obese patients induced by a very low-calorie diet.

METHODS

We evaluated 120 patients selected from a university hospital. Body composition was assessed before and after the diet provided during hospitalization, and changes in weight, body mass index, and neck, waist and hip circumferences were analyzed. Bioimpedance was used to obtain body fat and fat-free mass values. The data were categorized by gender, age, body mass index and diabetes diagnosis.

RESULTS

The patients consumed the diet for 8 days. They presented a 5% weight loss (without significant difference among groups), which represented an 85% reduction in body fat. All changes in body circumference were statistically significant. There was greater weight loss and a greater reduction of body fat in men, but the elderly showed a significantly higher percentage of weight loss and greater reductions in body fat and fat-free mass. Greater reductions in body fat and fat-free mass were also observed in superobese patients. The changes in the diabetic participants did not differ significantly from those of the non-diabetic participants.

CONCLUSIONS

The use of a VLCD before bariatric surgery led to a loss of weight at the expense of body fat over a short period, with no significant differences in the alteration of body composition according to gender, age, body mass index and diabetes status.

Are Raw BIA Variables Useful for Predicting Resting Energy Expenditure in Adults with Obesity?

This study aimed to develop and validate new predictive equations for resting energy expenditure (REE) in a large sample of subjects with obesity also considering raw variables from bioimpedance-analysis (BIA). A total of 2225 consecutive obese outpatients were recruited and randomly assigned to calibration (n = 1680) and validation (n = 545) groups. Subjects were also split into three subgroups according to their body mass index (BMI). The new predictive equations were generated using two models: Model 1 with age, weight, height, and BMI as predictors, and Model 2 in which raw BIA variables (bioimpedance-index and phase angle) were added. Our results showed that REE was directly correlated with all anthropometric and raw-BIA variables, while the correlation with age was inverse. All the new predictive equations were effective in estimating REE in both sexes and in the different BMI subgroups. Accuracy at the individual level was high for specific group-equation especially in subjects with BMI > 50 kg/m². Therefore, new equations based on raw-BIA variables were as accurate as those based on anthropometry. Equations developed for BMI categories did not substantially improve REE prediction, except for subjects with a BMI > 50 kg/m². Further studies are required to verify the application of those formulas and the role of raw-BIA variables for predicting REE.

Limitations of Fat-Free Mass for the Assessment of Muscle Mass in Obesity

BACKGROUND

A high amount of adipose tissue limits the accuracy of methods for body composition analysis in obesity.

OBJECTIVES

The aim was to quantify and explain differences in fat-free mass (FFM) (as an index of skeletal muscle mass, SMM) measured with bioelectrical impedance analysis (BIA), dual energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP), and deuterium dilution in comparison to multicompartment models, and to improve the results of BIA for obese subjects.

METHODS

In 175 healthy subjects (87 men and 88 women, BMI 20-43.3 kg/m2, 18-65 years), FFM measured by these methods was compared with results from a 3- (3C) and a 4-compartment (4C) model. FFM4C was compared with SMM measured by magnetic resonance imaging.

RESULTS

BIA and DXA overestimated and ADP underestimated FFM in comparison to 3C and 4C models with increasing BMI (all p < 0.001). -Differences were largest for DXA. In obesity, BIA results were improved: valuecorrected = -valueuncorrected - a(BMI - 30 kg/m2), a = 0.256 for FFM and a = 0.298 for SMM. SMM accounts for 45% of FFM in women and 49% in men.

CONCLUSIONS

In obesity, the use of FFM is limited by a systematic error of reference methods. In addition, SMM accounts for about 50% of FFM only. Corrected measurement of SMM by BIA can overcome these drawbacks.

Reduced Lean Body Mass and Cardiometabolic Diseases in Adult Males with Overweight and Obesity: A Pilot Study

Little is known about the reduction in lean body mass (LBM) and its health consequences in overweight and in obesity, especially in males. Therefore, we aimed to assess the prevalence of low LBM in treatment-seeking adult males with overweight and obesity and the association with cardiometabolic diseases, i.e., type 2 diabetes, cardiovascular diseases and dyslipidemia. A body composition assessment was conducted by a bio-impedance analyzer (InBody 170) among a total of 110 males, of whom 72 were overweight and obese and were referred to the Outpatient Clinic in the Department of Nutrition and Dietetics at Beirut Arab University (BAU) in Lebanon, and 38 were normal-weight participants of similar ages. The participants with overweight and obesity were then categorized as being with or without low LBM. Of the sample of 72 participants, 50 (69.4%) met the criteria for reduced LBM and displayed a significantly higher prevalence of cardiometabolic diseases (i.e., type 2 diabetes, cardiovascular diseases and dyslipidemia) than those with normal LBM (36.0% vs. 9.1%; p = 0.019). Logistic regression analysis showed that low LBM increases the odds of having cardiometabolic diseases by nearly 550% (odds ratio (OR) = 5.46, 95% confidence interval (CI) = 1.31–26.39, p < 0.05) after adjusting for total fat and central adiposity. Treatment-seeking adult males with overweight and obesity displayed a great prevalence of reduced LBM, which seems to be strongly associated with cardiovascular and metabolic diseases.

A new anthropometric index for body fat estimation in patients with severe obesity

Background

Body mass index (BMI) has been used to assess body adiposity, but it cannot adequately reflect body fat (BF) amount. The body adiposity index (BAI) has been shown a better performance than BMI for this purpose, but it can be inaccurate to estimate BF under extreme amounts of fat. Here, we propose a new anthropometric index, the Belarmino–Waitzberg (BeW) index, for specific estimation of BF in severely obese patients.

Methods

In 144 adult patients with severe obesity, BF was estimated by air displacement plethysmography (ADP), as the reference method, along with the follow anthropometric measurements: height, abdominal circumference (AC), hip circumference (HC), weight, BMI (weight/ height²) and BAI ([HC(cm) / height (m)^1.5) − 18] × 100). Patients were proportionately distributed into two distinct databases, the building model database (BMD) and the validation model database (VMD), which were applied to develop and validate the BeW index, respectively. The BeW index was tested for gender and ethnicity adjustment as independent variables. The agreement of BF% values obtained by the new index and by BAI with ADP was also assessed.

Results

The BF% was 52.05 ± 5.42 for ADP and 59.11 ± 5.95 for the BeW index (all results are expressed as the mean ± standard deviation). A positive Pearson correlation (r = 0.74), a good accuracy (Cb = 0.94), and a positive Lin’s concordance correlation (CCC = 0.70) were observed between the two groups. The 95% limits of individual agreement between the BeW index and ADP were 6.8 to 7.9%, compared to − 7.5 to 14.8% between the BAI and ADP. The new index, called the Belarmino–Waitzberg (BeW) index, showed an improvement of 2.1% for the R² value and a significant gender effect, therefore resulting in two different indexes for females and males, as follows: Female BeW = − 48.8 + 0.087 × AC(cm) + 1.147 × HC(cm) - 0.003 × HC(cm)2 and Male BeW = − 48.8 + 0.087 × AC(cm) + 1.147 × HC(cm) - 0.003 × HC(cm)2–7.195.

Conclusions

The new BeW index showed a good performance for BF estimation in patients with severe obesity and can be superior to the BAI for this purpose.

Physical performance measures in screening for reduced lean body mass in adult females with obesity

BACKGROUND & AIMS

Little is known about the reduction of lean body mass (LBM) in obesity, or how to identify it in standard clinical settings. We therefore aimed to assess the prevalence of low LBM in adult females with obesity, and to identify the reliability of simple tools for its screening in this population.

METHODS AND RESULTS

Dual-energy X-ray absorptiometry (DXA) body composition assessment was used to categorise 147 female participants with obesity as with or without low LBM, according to the new definition that takes into account both appendicular lean mass (ALM) and body mass index (BMI)-ALM/BMI <0.512. Participants were also administered the six-minute walking test, handgrip-strength test and 4-metre gait-speed test. Of the sample of 147 participants, 93 (63.3%) met the criteria for reduced LBM. Stepwise multivariate logistic regression analysis showed that the six-minute walking test was the only independent test associated with low LBM (OR = 0.992, 95%CI 0.987-0.998). Receiver operating characteristic (ROC) curve analysis found that the discriminating cut-off points of the tests considered were 470 m, 3.30 s (gait speed = 1.2 m/sec) and 23.5 kg respectively; the 4-metre gait-speed test seems to provide the best balance of sensitivity and specificity, and the greatest discriminatory power at 90% sensitivity.

CONCLUSIONS

Treatment-seeking adult females with obesity display a great prevalence of reduced LBM. The six-minute walking test was the only independent test associated with low LBM, but the 4-metre gait-speed test seems to be the most accurate functional test for screening for this condition in that population.

Prediction and evaluation of resting energy expenditure in a large group of obese outpatients

Background/Objectives:

The aim of this study was to compare resting energy expenditure (REE) measured (MREE) by indirect calorimetry (IC) and REE predicted (PREE) from established predictive equations in a large sample of obese Caucasian adults.

Subjects/Methods:

We evaluated 1851 obese patients (body mass index (BMI)>30 kg m⁻²) aged between 18a and 65 years. Data were obtained by comparing MREE with PREE, derived from different equations, within and between normal weight and obese groups. The mean differences between PREE and MREE as well as the accuracy prediction within ±10% level were investigated in the whole sample and in three subgroups, classified by BMI (Group 1=30–39.9 kg m⁻²; Group 2=40–49.9 kg m⁻²; Group 3>50 kg m⁻²).

Results:

We observed that FAO, Henry and Muller3 (body composition (BC)) equations provided good mean PREE–MREE (bias −0.7, −0.3 and 0.9% root mean standard error (RMSE) 273, 263 and 269 kcal per day, respectively); HB and Henry equations were more accurate individually (57 and 56.9%). Only the Muller1 (BC) equation gave the lowest PREE–MREE difference (bias −1.7% RMSE 228 kcal per day) in females, while Johnstone and De Lorenzo equations were the most accurate (55.1 and 54.8%). When the sample was split into three subgroups according to BMI, no differences were found in males; however, the majority of the equations included in this study failed to estimate REE in severely obese females (BMI>40 kg m⁻²). Overall, prediction accuracy was low (~55%) for all predictive equations, regardless of BMI.

Conclusions:

Different established equations can be used for estimating REE at the population level in both sexes. However, the accuracy was very low for all predictive equations used, particularly among females and when BMI was high, limiting their use in clinical practice. Our findings suggest that the validation of new predictive equations would improve the accuracy of REE prediction, especially for severely obese subjects (BMI>40 kg m⁻²).

Practical Considerations for Body Composition Assessment of Adults with Class II/III Obesity Using Bioelectrical Impedance Analysis or Dual-Energy X-Ray Absorptiometry

PURPOSE OF REVIEW

The purpose of this review is to explore the practical considerations for body composition assessment of adults with class II/III obesity. Studies assessing adults (18-64 years) with a body mass index (BMI) ≥35 kg/m² with bioelectrical impedance analysis (BIA) and/or dual-energy X-ray absorptiometry (DXA) were included.

RECENT FINDINGS

Twelve studies met inclusion criteria. Five considerations were identified: variances in equipment and technology, equipment weight capacity, subject positioning, tissue penetration, and total body hydration. In subjects with BMI ≥35 kg/m², BIA overestimated fat-free mass with scaling errors as BMI increased. DXA provided accurate and reliable body composition measures, but equipment-related barriers prevented assessment of some taller, wider, and heavier subjects. BIA is an unreliable method to assess body composition in class II/III obesity. Advancements in DXA technology (e.g., iDXA), methodology (e.g., subject positioning, longer scan times), and more inclusive testing criteria (e.g., use equipment limits not just BMI) may improve access and understanding of body composition in this cohort.

Modified body adiposity index for body fat estimation in severe obesity

BACKGROUND

The body adiposity index (BAI) comprises a simple method for estimating body fat (BF) that needs to be validated in patients with severe obesity. The present study aimed to determine BAI accuracy with respect to the determination BF in patients with severe obesity.

METHODS

A cross-sectional prospective study comparing two methods for BF estimation was conducted in 433 patients with severe obesity between August 2012 to December 2014. BF was estimated by bioelectrical impedance analysis (BIA) with specific equations developed for BF estimation in patients with severe obesity and BAI. The BF estimation in 240 patients with severe obesity (Group 1: G1) was used to evaluate BAI limitations and to develop a specific equation in this population. The new equation proposed was validated in another 158 patients with severe obesity (Group 2: G2).

RESULTS

There was a significant difference between BF determination by BIA and BAI (P = 0.039). The mean (SD) BF in G1 was 52.3% (6.1%) determined by BIA and 51.6% (8.1%) determined by BAI. Sex, waist-hip ratio (WHR) and obesity grade determined significant errors on BF estimation by BAI. A new equation (modified body adiposity index; MBAI) was developed by linear regression to minimise these errors [MBAI% = 23.6 + 0.5 × (BAI); add 2.2 if body mass index ≥ 50 kg m^-2 and 2.4 if WHR ≥ 1.05]. The new equation reduced the difference [1.2% (5.9%), P < 0.001 to 0.4% (4.12%), P = 0.315] and improved the correlation (0.6-0.7) between methods.

CONCLUSIONS

BAI present significant limitations in severe obesity and MBAI was effective for BF estimation in this population.

Validation study of multi-frequency bioelectrical impedance with dual-energy X-ray absorptiometry among obese patients

BACKGROUND

Body mass index (BMI) is the most common parameter for classifying nutritional status. However, body composition (BC) may vary considerably among individuals with identical BMIs; consequently, we need to assess BC efficiently. Bariatric surgery is the most effective method for treating obesity. To improve quality assessment of postoperative weight loss, it is essential to assess BC. Multi-frequency bioelectrical impedance analysis (BIA) is a practical assessment instrument, though limited when applied among the obese population. Despite dual-energy X-ray absorptiometry (DXA) being the current reference standard, it has physical limitations which restrict its practical application. This study, therefore, sought to correlate the results of BC assessments of same patient population using BIA and DXA.

METHODS

This was a cross-sectional validation study with patients invited to undergo a multi-frequency BIA (Inbody 720®) and afterwards a DXA examination Statistical analyses were done using the intraclass correlation coefficient (ICC), paired t-test and the Bland-Altman plot analysis.

RESULTS

A total of 108 patients were randomly selected, with 73 meeting the criteria for study inclusion. Most were female (89%) and had an average BMI of 40.17 ± 4.08 kg/m(2). An almost perfect correlation of fat (kg) and fat-free mass (kg) was found in results from the BIA and DXA examination (ICC = 0.832 and ICC = 0.899, respectively). A substantial correlation was also found between the percentage of body fat (%BF) and the percentage of fat-free mass (%FFM). The comparison made between the BIA and DXA using the t-test showed significant differences between all parameters. The Bland-Altman plot showed that the BIA method tends to underestimate the FM and overestimate the LM measurements when compared with DXA.

CONCLUSION

BIA proved to be a safe alternative for assessing BC in clinically severely obese patients and thus provides a more accessible evaluation tool for this population. But, consideration should be given to the formula added to the BIA measurement, adjusting the values to differences observed in order to reduce errors when compared with the DXA measurements.

The Impact of Feet Callosities, Arm Posture, and Usage of Electrolyte Wipes on Body Composition by Bioelectrical Impedance Analysis in Morbidly Obese Adults

OBJECTIVE

This study evaluated the impact of feet callosities, arm posture, and use of electrolyte wipes on body composition measurements by bioelectrical impedance analysis (BIA) in morbidly obese adults.

METHODS

36 morbidly obese patients (13 males, aged 28-70 years, BMI 41.6 ± 4.3 kg/m2) with moderate/severe feet callosities participated in this study. Body composition (percent body fat (%BF)) was measured while fasting using multi-frequency BIA (InBody 720®), before and after removal of callosities, with and without InBody® electrolyte wipes and custom-built auxiliary pads (to assess arm posture impact). Results from BIA were compared to air displacement plethysmography (ADP, BodPod®).

RESULTS

Median %BF was significantly higher with auxiliary pads than without (50.1 (interquartile range 8.2) vs. 49.3 (interquartile range 9.1); p < 0.001), while no differences were found with callosity removal (49.3 (interquartile range 9.1) vs. 50.0 (interquartile range 7.9); NS) or use of wipes (49.6 (interquartile range 8.5) vs. 49.3 (interquartile range 9.1); NS). No differences in %BF were found between BIA and ADP (49.1 (IQR: 8.9) vs. 49.3 (IQR: 9.1); NS).

CONCLUSION

Arm posture has a significant impact on %BF assessed by BIA, contrary to the presence of feet callosities and use of electrolyte wipes. Arm posture standardization during BIA for body composition assessment is, therefore, recommended.

Métodos de análise da composição corporal em adultos obesos

Os métodos de avaliação da composição corporal em obesos têm sido amplamente discutidos, uma vez que nesses indivíduos a avaliação é dificultada devido às limitações dos equipamentos e características dos métodos utilizados. Esta sessão temática tem o objetivo de esclarecer as características, vantagens e limitações dos métodos de avaliação da composição corporal em adultos obesos. A quantificação de gordura corporal e mas-sa livre de gordura, assim como a avaliação da perda de massa muscular e de massa óssea em obesos são temas de grande interesse científico, uma vez que são utilizados para diagnosticar a obesidade osteosarcopênica. A avaliação da composição corporal de obesos pelo modelo de múltiplos compartimentos é padrão-ouro na prática científica. Por outro lado, o método de absorciometria radiológica de feixe duplo é considerado o padrão de referência em pesquisas e na prática clínica. Estudos indicam que a ressonância magnética e a tomografia computadorizada, em alguns casos, são fortemente correlacionadas com a absorciometria radiológica de feixe duplo. Os demais métodos apresentam limitações em avaliar a composição corporal, bem como suas modificações durante a redução ponderal em indivíduos obesos.

The effects of exercise training in addition to energy restriction on functional capacities and body composition in obese adults during weight loss: a systematic review

BACKGROUND

Obesity is associated with impairments of physical function, cardiovascular fitness, muscle strength and the capacity to perform activities of daily living. This review examines the specific effects of exercise training in relation to body composition and physical function demonstrated by changes in cardiovascular fitness, and muscle strength when obese adults undergo energy restriction.

METHODS

Electronic databases were searched for randomised controlled trials comparing energy restriction plus exercise training to energy restriction alone. Studies published to May 2013 were included if they used multi-component methods for analysing body composition and assessed measures of fitness in obese adults.

RESULTS

Fourteen RCTs met the inclusion criteria. Heterogeneity of study characteristics prevented meta-analysis. Energy restriction plus exercise training was more effective than energy restriction alone for improving cardiovascular fitness, muscle strength, and increasing fat mass loss and preserving lean body mass, depending on the type of exercise training.

CONCLUSION

Adding exercise training to energy restriction for obese middle-aged and older individuals results in favourable changes to fitness and body composition. Whilst weight loss should be encouraged for obese individuals, exercise training should be included in lifestyle interventions as it offers additional benefits.

Surgical weight loss: impact on energy expenditure

Diet-induced weight loss is often limited in its magnitude and often of short duration, followed by weight regain. On the contrary, bariatric surgery now commonly used in the treatment of severe obesity favors large and sustained weight loss, with resolution or improvement of most obesity-associated comorbidities. The mechanisms of sustained weight loss are not well understood. Whether changes in the various components of energy expenditure favor weight maintenance after bariatric surgery is unclear. While the impact of diet-induced weight loss on energy expenditure has been widely studied and reviewed, the impact of bariatric surgery on total energy expenditure, resting energy expenditure, and diet-induced thermogenesis remains unclear. Here, we review data on energy expenditure after bariatric surgery from animal and human studies. Bariatric surgery results in decreased total energy expenditure, mainly due to reduced resting energy expenditure and explained by a decreased in both fat-free mass and fat mass. Limited data suggest increased diet-induced thermogenesis after gastric bypass, a surgery that results in gut anatomical changes and modified the digestion processes. Physical activity and sustained intakes of dietary protein may be the best strategies available to increase non-resting and then total energy expenditure, as well as to prevent the decline in lean mass and resting energy expenditure.

Prediction of whole-body and segmental body composition by bioelectrical impedance in morbidly obese subjects

BACKGROUND

Validated equations for body composition analysis using bioelectrical impedance (BIA) in morbidly obese (MO) subjects are scarce. Thus, our aim was todevelop new equations from physical and BIA parameters to estimate whole-body and segmental body composition inMO subjects, with dual-energy X-ray absorptiometry(DXA) as the reference method.

METHODS

A cross-sectional study on 159 Caucasian MO subjects (female 78%, age 43.5 ± 11.8 years, BMI 45.6 ± 4.9 kg/m2) divided in two groups was conducted: model building cohort (n = 110) and model validation cohort (n 0 49). Stepwise regression analysis was used to develop specific fat free mass (FFM) and fat mass (FM) equations.

RESULTS

Gender, body weight, and height2/impedance accounted, respectively, for 89.4% (p < 0.001) and 89.3% (p < 0.001) of the variability of DXA-total FFM in the two cohorts. Using the new equation, the mean difference between the DXA-FFM and BIA-FFM estimates was +0.180 kg (95% CI: -0.34 to +0.7 kg, p 0 NS), and the resulting limits of agreement were +6.76 and −6.40 kg. Similarly, good estimates of DXA truncal-, android-, and gynoid-FM from anthropometric and BIA parameters could be obtained from weight, height2/impedance, and waist and hip circumferences (respectively, R2 adjusted: 0.657, 0.776, and 0.770; p < 0.001).

CONCLUSIONS

The new equations derived from physical and BIA parameters provide accurate estimates of body composition in MO subjects.

Bariatric surgery: impact on body composition after Roux-en-Y gastric bypass

BACKGROUND

The aim of this study was to analyze the impact of bariatric surgery on the body composition of patients suffering from class III obesity at different postoperative time intervals.

METHODS

The body composition of 114 patients undergoing Roux-en-Y gastric bypass surgery was measured prior to surgery (T0) and then 30 (T30) and 180 (T180) days following surgery. Body composition was evaluated using the following parameters: total body mass, body mass index, excess weight, percentage of excess weight loss, relative body fat (%F), lean body mass (LBM), and fat tissue mass (FTM). To determine these variables, validated formulas and equations proper to obese men and women were employed.

RESULTS

A significant reduction in %F (41.5%), LBM (20.3%), FTM (37.9%) was noted at each time interval (p ≤ 0.01).

CONCLUSIONS

Bariatric surgery proved to be effective in reducing total body mass and body fat at every time interval. However, dietary measures emphasizing adequate protein intake may be implemented in order to reduce loss of LBM and, coupled with frequent physical activity, may help curtail the impact the surgery has on morphological variables.

Assessment tools in obesity - psychological measures, diet, activity, and body composition

The global increase in the prevalence of obesity has led to an increased need for measurement tools for research, management and treatment of the obese person. The physical size limitations imposed by obesity, variations in body composition from that of normal weight, and a complex psychopathology all pose tremendous challenges to the assessment of an obese person. There is little published research regarding what tools can be used with confidence. This review is designed to provide researchers and clinicians with a guide to the current and emerging measurement tools specifically associated with obesity research and practice. Section 1 addresses psychological measures of well being. Sections 2, 3, and 4 focus on the assessment of food intake, activity, and body composition. All sections address basic challenges involved in the study and management of obesity, and highlight methodological issues associated with the use of common assessment tools. The best available methods for use in the obese both in research and clinical practice are recommended.

Clinical usefulness of a new equation for estimating body fat

OBJECTIVE

To assess the predictive capacity of a recently described equation that we have termed CUN-BAE (Clínica Universidad de Navarra-Body Adiposity Estimator) based on BMI, sex, and age for estimating body fat percentage (BF%) and to study its clinical usefulness.

RESEARCH DESIGN AND METHODS

We conducted a comparison study of the developed equation with many other anthropometric indices regarding its correlation with actual BF% in a large cohort of 6,510 white subjects from both sexes (67% female) representing a wide range of ages (18-80 years) and adiposity. Additionally, a validation study in a separate cohort (n = 1,149) and a further analysis of the clinical usefulness of this prediction equation regarding its association with cardiometabolic risk factors (n = 634) was carried out.

RESULTS

The mean BF% in the cohort of 6,510 subjects determined by air displacement plethysmography was 39.9 ± 10.1%, and the mean BF% estimated by the CUN-BAE was 39.3 ± 8.9% (SE of the estimate, 4.66%). In this group, BF% calculated with the CUN-BAE showed the highest correlation with actual BF% (r = 0.89, P < 0.000001) compared with other anthropometric measures or BF% estimators. Similar agreement was found in the validation sample. Moreover, BF% estimated by the CUN-BAE exhibits, in general, better correlations with cardiometabolic risk factors than BMI as well as waist circumference in the subset of 634 subjects.

CONCLUSIONS

CUN-BAE is an easy-to-apply predictive equation that may be used as a first screening tool in clinical practice. Furthermore, our equation may be a good tool for identifying patients at cardiovascular and type 2 diabetes risk.

An obese body mass increases the adverse effects of HIV/AIDS on balance and gait

BACKGROUND

Balance and gait problems have been detected among patients with HIV/AIDS. The extent to which these problems are exacerbated by either frailty or obesity has not been examined. Objective The purpose of this study was to compare participants who differed in body mass and the presence or absence of HIV/AIDS.

DESIGN

This was a cross-sectional study.

METHODS

Quantitative measurements were obtained from 86 participants who were HIV-type 1 (HIV-1) seronegative and 121 participants who were seropositive divided into subgroups based on their body mass index (BMI <21, 21-29, or >29 kg/m(2)).

RESULTS

Participants who were seropositive were impaired relative to seronegative controls on several indices, including the limit of stability, sway amplitude and sway strategy, gait initiation time, and gait speed during a fast pace condition. Participants who were obese also exhibited impairments, which were evident during assessments of the limit of stability, nonpreferred leg stance time, sway strategy, normal and fast gait speed, fast gait initiation time, and 360-degree turn time. Importantly, the analysis revealed that participants with both attributes were more impaired than those with either or neither attribute: patients who were obese and seropositive were more impaired in fast gait initiation time and cadence, nonpreferred leg stance time, 360-degree turn time, and sway strategy scores. Limitations The validity of BMI as a measure of body mass can be challenged. In addition, the validity of chair rise time and 360-degree turn time as estimates of lower-extremity strength (force-generating capacity) can be argued.

CONCLUSIONS

The present findings have an obvious and unfortunate implication: as more patients who are HIV-1 seropositive join the seronegative community in becoming obese, the effects of obesity and their disease may summate and their risk for balance and gait problems may increase.

Body adiposity and type 2 diabetes: increased risk with a high body fat percentage even having a normal BMI

Obesity is the major risk factor for the development of prediabetes and type 2 diabetes. BMI is widely used as a surrogate measure of obesity, but underestimates the prevalence of obesity, defined as an excess of body fat. We assessed the presence of impaired glucose tolerance or impaired fasting glucose (both considered together as prediabetes) or type 2 diabetes in relation to the criteria used for the diagnosis of obesity using BMI as compared to body fat percentage (BF%). We performed a cross-sectional study including 4,828 (587 lean, 1,320 overweight, and 2,921 obese classified according to BMI) white subjects (66% females), aged 18-80 years. BMI, BF% determined by air-displacement plethysmography (ADP) and conventional blood markers of glucose metabolism and lipid profile were measured. We found a higher than expected number of subjects with prediabetes or type 2 diabetes in the obese category according to BF% when the sample was globally analyzed (P < 0.0001) and in the lean BMI-classified subjects (P < 0.0001), but not in the overweight or obese-classified individuals. Importantly, BF% was significantly higher in lean (by BMI) women with prediabetes or type 2 diabetes as compared to those with normoglycemia (NG) (35.5 ± 7.0 vs. 30.3 ± 7.7%, P < 0.0001), whereas no differences were observed for BMI. Similarly, increased BF% was found in lean BMI-classified men with prediabetes or type 2 diabetes (25.2 ± 9.0 vs. 19.9 ± 8.0%, P = 0.008), exhibiting no differences in BMI or waist circumference. In conclusion, assessing BF% may help to diagnose disturbed glucose tolerance beyond information provided by BMI and waist circumference in particular in male subjects with BMI <25 kg/m(2) and over the age of 40.

Body mass index classification misses subjects with increased cardiometabolic risk factors related to elevated adiposity

CONTEXT

Body mass index (BMI) is widely used as a measure of overweight and obesity, but underestimates the prevalence of both conditions, defined as an excess of body fat.

OBJECTIVE

We assessed the degree of misclassification on the diagnosis of obesity using BMI as compared with direct body fat percentage (BF%) determination and compared the cardiovascular and metabolic risk of non-obese and obese BMI-classified subjects with similar BF%.

DESIGN

We performed a cross-sectional study.

SUBJECTS

A total of 6123 (924 lean, 1637 overweight and 3562 obese classified according to BMI) Caucasian subjects (69% females), aged 18-80 years.

METHODS

BMI, BF% determined by air displacement plethysmography and well-established blood markers of insulin sensitivity, lipid profile and cardiovascular risk were measured.

RESULTS

We found that 29% of subjects classified as lean and 80% of individuals classified as overweight according to BMI had a BF% within the obesity range. Importantly, the levels of cardiometabolic risk factors, such as C-reactive protein, were higher in lean and overweight BMI-classified subjects with BF% within the obesity range (men 4.3 ± 9.2, women 4.9 ± 19.5 mg l(-1)) as well as in obese BMI-classified individuals (men 4.2 ± 5.5, women 5.1 ± 13.2 mg l(-1)) compared with lean volunteers with normal body fat amounts (men 0.9 ± 0.5, women 2.1 ± 2.6 mg l(-1); P<0.001 for both genders).

CONCLUSION

Given the elevated concentrations of cardiometabolic risk factors reported herein in non-obese individuals according to BMI but obese based on body fat, the inclusion of body composition measurements together with morbidity evaluation in the routine medical practice both for the diagnosis and the decision-making for instauration of the most appropriate treatment of obesity is desirable.

New fat free mass - fat mass model for use in physiological energy balance equations

Background

The Forbes equation relating fat-free mass (FFM) to fat mass (FM) has been used to predict longitudinal changes in FFM during weight change but has important limitations when paired with a one dimensional energy balance differential equation. Direct use of the Forbes model within a one dimensional energy balance differential equation requires calibration of a translate parameter for the specific population under study. Comparison of translates to a representative sample of the US population indicate that this parameter is a reflection of age, height, race and gender effects.

Results

We developed a class of fourth order polynomial equations relating FFM to FM that consider age, height, race and gender as covariates eliminating the need to calibrate a parameter to baseline subject data while providing meaningful individual estimates of FFM. Moreover, the intercepts of these polynomial equations are nonnegative and are consistent with observations of very low FM measured during a severe Somali famine. The models preserve the predictive power of the Forbes model for changes in body composition when compared to results from several longitudinal weight change studies.

Conclusions

The newly developed FFM-FM models provide new opportunities to compare individuals undergoing weight change to subjects in energy balance, analyze body composition for individual parameters, and predict body composition during weight change when pairing with energy balance differential equations.

Dynamics of change in total and regional body composition after gastric bypass in obese patients

Little is known on patterns of change over time in body composition, especially lean body mass (LBM), during massive weight loss after Roux-en-Y gastric bypass (RYGB) in obese patients. We performed sequential measurements of total and regional body composition in patients after RYGB, and we compared a subsample of patients after surgery to a nonsurgical control group of similar age and body fatness. We used dual-energy X-ray absorptiometry (DXA) before and at 3, 6, and 12 months after RYGB in 42 obese women (before surgery: age 39.5 +/- 11.6 years; BMI 44.6 +/- 6.1 kg/m(2); mean +/- s.d.) and in 48 control obese women referred for nonsurgical weight management, before weight loss. During 1-year follow-up after RYGB, there was a continuous decrease in body weight (-36.0 +/- 12.5 kg at 1 year), total fat mass (FM) (-26.0 +/- 9.1 kg), as well as in trunk and appendicular FM. In contrast, the decrease in total LBM (-9.8 +/- 4.8 kg at 1 year), as well as in trunk and appendicular LBM, plateaued after 3-6 months. Rates of loss in weight, FM, and LBM were highest during the first 3-month period after RYGB (6.4 +/- 1.8, 4.1 +/- 1.7, and 2.3 +/- 1.2 kg/month, respectively), then decreased continuously for FM but plateaued for LBM. There was no evidence of a decrease in total, trunk, or appendicular LBM in weight-reduced subjects compared to the control group. In conclusion, follow-up of these obese women revealed a differential pattern of change in FM and LBM after RYGB. Despite an important loss in LBM, especially during the 3-6 months of initial period, LBM appears to be spared thereafter.