Advances in the science and application of body composition measurement

Skeletal muscle index is associated with long term outcomes after lobectomy for non-small cell lung cancer

BACKGROUND

Skeletal muscle indices have been associated with improved peri-operative outcomes after surgical resection of non-small-cell lung cancer (NSCLC). However, it is unclear if these indices can predict long term cancer specific outcomes.

METHODS

NSCLC patients undergoing lobectomy at our institute between 2009-2015 were included in this analysis (N = 492). Preoperative CT scans were used to quantify skeletal muscle index (SMI) at L4 using sliceOmatic software. Cox proportional modelling was performed for overall (OS) and recurrence free survival (RFS).

RESULTS

For all patients, median SMI was 45.7 cm2/m2 (IQR, 40-53.8). SMI was negatively associated with age (R = -0.2; p < 0.05) and positively associated with BMI (R = 0.46; P < 0.05). No association with either OS or RFS was seen with univariate cox modelling. However, multivariable modelling for SMI with patient age, gender, race, smoking status, DLCO and FEV1 (% predicted), American Society of Anesthesiology (ASA) score, tumor histology and stage, and postoperative neoadjuvant therapy showed improved OS (HR = 0.97; P = 0.0005) and RFS (HR = 0.97; P = 0.01) with SMI. Using sex specific median SMI as cutoff, a lower SMI was associated with poor OS (HR = 1.65, P = 0.001) and RFS (HR = 1.47, P = 0.03).

CONCLUSIONS

SMI is associated with improved outcomes after resection of NSCLC. Further studies are needed to understand the biological basis of this observation. This study provides additional rationale for designing and implementation of rehabilitation trials after surgical resection, to gain durable oncologic benefit.

Machine learning modeling practices to support the principles of AI and ethics in nutrition research

BACKGROUND

Nutrition research is relying more on artificial intelligence and machine learning models to understand, diagnose, predict, and explain data. While artificial intelligence and machine learning models provide powerful modeling tools, failure to use careful and well-thought-out modeling processes can lead to misleading conclusions and concerns surrounding ethics and bias.

METHODS

Based on our experience as reviewers and journal editors in nutrition and obesity, we identified the most frequently omitted best practices from statistical modeling and how these same practices extend to machine learning models. We next addressed areas required for implementation of machine learning that are not included in commercial software packages.

RESULTS

Here, we provide a tutorial on best artificial intelligence and machine learning modeling practices that can reduce potential ethical problems with a checklist and guiding principles to aid nutrition researchers in developing, evaluating, and implementing artificial intelligence and machine learning models in nutrition research.

CONCLUSION

The quality of AI/ML modeling in nutrition research requires iterative and tailored processes to mitigate against potential ethical problems or to predict conclusions that are free of bias.

Commercial Devices Provide Estimates of Energy Balance with Varying Degrees of Validity in Free-Living Adults

BACKGROUND

The challenges of accurate estimation of energy intake (EI) are well-documented, with self-reported values 12%-20% below expected values. New approaches rely on gold-standard assessments of the other components of energy balance, energy expenditure (EE) and energy storage (ES), to estimate EI.

OBJECTIVES

The purpose of this study was to evaluate the validity, repeatability, and measurement error of consumer devices when estimating energy balance in a free-living population.

METHODS

Twenty-four healthy adults (14 women, 10 men; mean ± SD age: 30.7 ± 8.2 y) completed two 14-d assessment periods, including assessments of EE and ES using gold-standard [doubly labeled water (DLW) and DXA] and commercial devices [Fitbit Alta HR activity monitor (Alta) and Fitbit Aria wireless body composition scale (Aria)], and of EI by dietician-administered recalls. Accuracy and validity were assessed using Spearman correlation, interclass correlation, mean absolute percentage error, and equivalency testing. We also applied linear measurement error modeling including error in gold-standard devices and within-subject repeated-measures design to calibrate consumer devices and quantify error.

RESULTS

There was moderate to strong agreement for EE between the Fitbit Alta and DLW at each time point (rs = 0.82 and 0.66 for Times 1 and 2, respectively). There was weak agreement for ES between the Fitbit Aria and DXA (rs = 0.15 and 0.49 for Times 1 and 2, respectively). Correlations between methods to assess EI ranged from weak to strong, with agreement between the DXA/DLW-calculated EI and dietary recalls being the highest (rs = 0.63 for Time 1 and 0.73 for Time 2). Only EE from the Fitbit Alta at Time 1 was equivalent to the DLW value using equivalency testing.

CONCLUSIONS

Commercial devices provide estimates of energy balance in free-living adults with varying degrees of validity compared to gold-standard techniques. EE estimates were the most robust overall, whereas ES estimates were generally poor.

The importance of body composition assessment in the rehabilitation process

Introduction. This personal study provides several aspects of the importance of body composition assessment in rehabilitation process in order to manage fat mass (FM), fat-free mas imbalances (FFM), pre-sarcopenia status, sarcopenia and risks association and to improve global functionality. Health outcomes and risk estimations regarding fat mass and skeletal muscle mass (SMM) plays a major role and should be integrated into the rehabilitation process routine in order to avoid functional impairment and physical disability by applying specific kinetic programs. Material and method. A number of 14 subjects classified as outpatients who have received physical therapy at home- kinesiotherapy for post-fracture / dislocation status of the lower limbs in accordance with the medical recommendations and legislation in force. At the end of the rehabilitation phase, the body composition was measured using bio impedance in order to adjust the next step of the active rehabilitation. The measurements were obtained with a completely bioelectrical impedance analyzer (BIA). Single frequency BIA (SF-BIA) was used. For each subject major body compartments determined as FFM (including bone mineral tissue, total body water-TBW and visceral protein), SMM and FM were measured as a tissue-system by means of linear empirical equations stored in the system memory together with personal physical data. IBM SPSS software version 25 was used for statistical analysis. Results and discussions. Four age groups determined as follows: 21.43% for 18-39 years, 50-69 years, >70 years each and 35.71% for 40-49 years, based on the rate of muscle loss, because its integrity is essential for rehabilitation program. From the 14 subjects there are 57.14 % men and 42.86% women, from urban environment 78.57% and rural 21.43%. Mean Age is 48.79 years ± 18.792 Std. Deviation. Fat mass from BIA recorded 21.43% cases low and normal each, and high/very high 57.14% of total cases. Consequently, of BMI (body mass index) association, 57.14% are at normal weight, 35.71% overweight and with obesity and 7.14% underweight. One Sample Chi-Square test applied to BMI Type Associate with FM reveals the statistical significance, < .05(.014). Fat-free mass index (FFMI), fat mass index (FMI), skeletal mass index (SMI) were computed by adjusted with height square. FMI somatotype components results are 64.3% adipose cases, 21.4% intermediate and 14.3% lean. One Sample Chi-Square test applied to FMI Types reveals the statistical significance < .05(.046). Regression equation of standard BMI and FMI with scatter plots for 77.8% of cases was computed in the present study. FFMI somatotype components recorded 57.1% intermediate cases, 21.4% slender and solid each. Regression equation of standard BMI and FFMI with scatter plots for 57.4% of cases was computed. Three patients exceeded 15 seconds at the chair stand test so probable sarcopenia was identified. From BIA were extracted the value for the skeletal mass and SMI was calculated by height adjusted: 13 (92.86%) cases have normal values and one (7.14%) case have optimal value. Regression equation of standard BMI and SMI with scatter plots for 66.4% of cases was computed. Pearson correlation (CI =99%) denotes strong statistical relationship between BMI and FMI (r=0.882), FFMI (r=0.815), Age (r=0.659), Water (r=-0.693). FMI also correlates strongly with Age (r= 0.707), Water (r=-0.925) and Proteins values (r=-0.819). FFMI also correlates strongly with SMI (r=0.984). Water correlates with Protein (r=0.848, CI = 99%). Beta regression analysis strongly correlates SMI prediction with FFMI (ß=0.731), Water (ß=0.138) and Protein (ß=-0.370) for p<0.05. Anova significance of .000 (CI=99%) with applicability of 99.8% of the cases (R2 =0.998) proved that constant predictors: Water (%), FFMI, Proteins (%), FMI, BMI interact to influence SMM variability. 64.25% of subjects recorded an insufficient water level and 71.43% of subjects recorded an insufficient proteins level. Body composition evaluation should be integrated into routine clinical practice for the initial assessment and sequential follow-up and the strongest point of BIA is the possibility to replace invasive laboratory analysis with a quick, noninvasive test that can be carried out in a medical office. Body composition evaluation should be performed at the different stages of the disease, during the course of treatments and the rehabilitation phase. Conclusions. For each patient specific kinetic program will be developed. FMI increase (64.3% adipose cases) denotes the risk of metabolic syndrome and insulin resistance. Consequently, resistive and concentric exercises will be applied. For FFMI loss (57.1% intermediate cases, 21.4% slender) and SMI increasing (92.86% cases have normal values but not optimal ones, 21.43% pre-sarcopenia detected by positive chair test) resistance, eccentric/concentric exercises should be applied. All kinetic programs will be preceded by warm-up and followed by stretching taking into account cardiac reserve for each patient. Maximal/sub-maximal force exercises will be used age-related. Additional water (64.25% of subjects recorded an insufficient water level) and proteins levels (71.43% of subjects recorded an insufficient proteins level) must be balanced by nutritional support in accordance with rehabilitation consult and current physician approval in the interdisciplinary team. BIA may be an important supporting tool for health professionals in order to customize the rehabilitation programs for each patient. Keywords: body composition, rehabilitation, bioelectrical impedance, fat-free mass index, fat mass index, skeletal muscle index,

Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: children and adolescents

The Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Children and Adolescents was developed by dietitians, physicians, and pediatric hematologists from 10 Brazilian reference centers in hematopoietic stem cell transplantation. The aim was to emphasize the importance of nutritional status and body composition during treatment, as well as the main characteristics related to patient´s nutritional assessment. This consensus is intended to improve and standardize nutrition therapy during hematopoietic stem cell transplantation. The consensus was approved by the Brazilian Society of Bone Marrow Transplantation.

Bioelectrical impedance analysis as a quantitative measure of sarcopenia in head and neck cancer patients treated with radiotherapy

BACKGROUND AND PURPOSE

Sarcopenia is associated with decreased survival in head and neck cancer patients treated with radiotherapy. This study sought to determine whether in-clinic multifrequency bioelectrical impedance analysis (BIA) can identify survival-associated sarcopenia in patients with head and neck cancer.

MATERIALS AND METHODS

This prospective observational study enrolled 50 patients with head and neck cancer undergoing radiation therapy. Baseline BIA measures of skeletal muscle (SM) mass, fat-free mass (FFM), and fat mass (FM) were compared to CT-based estimates using linear regression. Sex-specific BIA-derived thresholds for sarcopenia were defined by the maximum Youden Index on receiver operator characteristic (ROC) curves. Patients were stratified by sarcopenia status and OS was compared using the Kaplan-Meier method and log-rank test.

RESULTS

Among 48 evaluable patients, BIA measures of body composition were strongly correlated with CT measures: SM mass (r = 0.97; R2 = 0.94; p < 0.0001), FFM (r = 0.97; R2 = 0.94; p < 0.0001) and FM (r = 0.95; R2 = 0.90; p < 0.0001). SM mass index < 9.19 kg/m2 identified sarcopenia men with high sensitivity (91.7%) and specificity (92.9%), whereas in women SM mass index < 6.53 kg/m2 was sensitive for sarcopenia (100%), but not specific. Patients with sarcopenia, defined by either CT or BIA, exhibited decreased OS (HR = not estimable; CT p = 0.009; BIA p = 0.03).

CONCLUSION

BIA provides accurate estimates of body composition in head and neck cancer patients. Implementation of BIA in clinical practice may identify patients with sarcopenia at risk for poor survival.

Effectiveness of an 8-Week Aerobic Exercise Program on Autonomic Function in People Living with HIV Taking Anti-Retroviral Therapy: A Pilot Randomized Controlled Trial

This study assessed the effectiveness of an 8-week aerobic exercise program on heart rate variability (HRV) in people living with HIV taking antiretroviral therapy. Twenty-six participants were randomly assigned to a control group or an aerobic exercise group. Resting HRV was measured for 5 min in supine position using an electrocardiogram. Estimated maximal oxygen uptake (VO_2max) was assessed through a treadmill 6-min walk test. The training program consisted of aerobic exercise thrice per week at 65%-75% of heart rate max for 45 min per session. Repeated measures ANOVA was used to test for differences between groups, and Spearman's rho was used to assess for the correlation between HRV measures and estimated VO_2max. There was no significant group by time interactions for any of the HRV indices. However, the standard deviation of normal-to-normal (NN) R-R intervals increased significantly in the aerobic exercise group (pre: 46.97 ± 32.70 ms vs. post: 59.49 ± 37.20 ms, p = .045). There was a strong correlation between the VO_2max and the standard deviation of NN intervals (SDNN) (r = 0.617; p = .002). There was a moderate correlation between VO_2max and the square root of the mean squared differences of successive normal-to-normal intervals (rMSSD) (r = 0.424; p = .049), the low frequency power (r = 0.506; p = .016), and the standard deviation of differences between successive differences of normal-to-normal intervals (SDSD) (r = 0.424; p = .049). While differences in HRV were not observed between groups, our data suggest that overall autonomic function can improve across time with aerobic exercise, and these changes are associated with greater levels of VO_2max. These results advocate the importance of improvements in HRV given their association with lower risk of cardiovascular disease and mortality.

Fat-free mass characteristics of Hispanic adults: Comparisons with non-Hispanic Caucasians and cadaver reference values

BACKGROUND

A four-compartment (4C) model quantifies fat, water, mineral and residual. As such, 4C models are more accurate than two-compartment (2C) models based off cadaver reference values (RV), which necessitate assumptions regarding fat-free mass (FFM) characteristics. Nonetheless, research has yet to determine whether the FFM characteristics of Hispanics are similar to non-Hispanic Caucasians and RV.

AIM

The aim of this analysis was to compare the FFM characteristics of Hispanics to non-Hispanic Caucasians and cadaver RV.

METHODS

Data from 2 separate research centers were pooled to create a sample of 100 and 119 Hispanic males and females (age: 18-54 yrs; BMI: 16.46-42.27 kg/m²), respectively, and 47 and 55 non-Hispanic Caucasian males and females (age: 18-54 yrs; BMI: 16.00-36.67 kg/m²), respectively (n = 331). A 4C model was determined using bioimpedance analysis for hydration, dual energy X-ray absorptiometry for mineral, and air displacement plethysmography for body density (4C-ADP). FFM was calculated via the 4C-ADP and FFM characteristics (i.e., density [D_FFM], water [TBW:FFM], bone mineral [Mo:FFM], and residual [R:FFM]) were compared between sexes and ethnicities using a one-way ANOVA and against RV via a one sample t-test.

RESULTS

In Hispanics, all FFM characteristics significantly differed from cadaver RV (all p < 0.05). In contrast, D_FFM and TBW:FFM of non-Hispanic Caucasians were similar to cadaver RV for both sexes (all p > 0.05). Moreover, the R:FFM of non-Hispanic Caucasian females did not differ from cadaver RV (p = 0.403) whereas all other comparisons were significantly different (all p < 0.05). Sex comparisons within Hispanic participants revealed FFM characteristics were similar between males and females other than Mo:FFM (p < 0.001) whereas all FFM characteristics were similar between non-Hispanic Caucasian males and females (all p > 0.05). All of the ethnicity comparisons within males were statistically significant (all p < 0.05). Moreover, ethnicity comparisons within females were statistically significant for all comparisons other than Mo:FFM (p = 0.258).

CONCLUSION

The observed differences in FFM characteristics of Hispanics as compared to non-Hispanics Caucasians and reference values indicate that allied health professionals should employ appropriate caution when estimating body composition via 2C models in Hispanic populations.

Effects of resistance training on depression and cardiovascular disease risk in Black men: Protocol for a randomized controlled trial

BACKGROUND

Depression is severely undertreated in Black men. This is primarily because Black men are less likely to seek traditional psychiatric treatment, have less access and more barriers to treatment, and perceive more stigma associated with treatment. Depression contributes to cardiovascular disease (CVD), and Black men have the highest rate of mortality from CVD. Resistance training (RT) can have beneficial effects on both depression and CVD. This study will be the first randomized controlled trial to test the effects of RT on depression and cardiovascular health in a sample of depressed Black men.

METHOD/DESIGN

Fifty Black men with clinically significant symptoms of depression will be randomized to either (a) a 12-week RT or (b) an attention-control group. Behavioral Activation techniques will be used to support adherence to home-based RT goals. Both groups will meet on-site twice/week during the 12-week program, and follow-up assessments will occur at the end-of-treatment and 3 months post-treatment. Qualitative interviews will be conducted after the 3-month follow-up. The objectives of this study are (1) to assess the feasibility and acceptability of recruitment, retention, and intervention procedures, (2) to obtain preliminary evidence of efficacy, and (3) to explore potential mediators of the effects of RT on depression.

DISCUSSION

This study will advance the field of minority men's health by producing new data on the effects of RT for depression, the potential mechanisms of action that may support its use, and its effects on markers of CVD risk in Black men.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03107039).

Exercise during adjuvant treatment for colorectal cancer: treatment completion, treatment-related toxicities, body composition, and serum level of adipokines

Objectives: The primary aim of this study was to investigate the beneficial effect of exercise on completion rates of adjuvant treatment, which is one of the major prognostic factors among patients with locally advanced colorectal cancer after undergoing curative resection followed by adjuvant treatment. Design: Prospective pilot study Methods: We assigned patients who were scheduled to undergo adjuvant treatment (N=39) to the exercise group or the control group in a 2:1 ratio in the order of enrollment. Patients completed questionnaires and underwent assessment of the outcome variables at the start of chemotherapy and upon completion of treatment. Results: A fivefold lower possibility of dose adjustment in the exercise group compared to the control group was demonstrated (OR, 0.188; p=0.023; 95% CI, 0.044-0.793). A significantly smaller proportion of the exercise group had grade 3 or 4 nausea (p=0.018) and neurotoxicity (P=0.024) symptoms. Muscle to fat ratios were significantly reduced in the control group (p=0.039), but not in the exercise group (p=0.742). Serum levels of leptin were significantly increased in the control group (p=0.038), but not in the exercise group (p=0.073). Serum levels of adiponectin were significantly increased in the exercise group (p=0.026) but tended to be decreased in the control group with no statistical significance (p=0.418). Conclusions: Exercise training among patients with colorectal cancer was found to have a beneficial impact on adjuvant treatment completion rates and treatment-associated toxicities. This program was also shown to be beneficial to patients' body compositions and serum levels of adipokines.

Sarcopenic obesity derived from PET/CT predicts mortality in lymphoma patients undergoing hematopoietic stem cell transplantation

BACKGROUND

Sarcopenic Obesity (SO) is associated with worse survival among chemotherapy recipients. Research on SO is scarce among lymphoma patients receiving Hematopoietic Stem Cell Transplantation (HSCT).

AIM

assess prevalence of SO pre-HSCT (T0) and 3 months post-HSCT (T1) in lymphoma patients and determine the power of SO at T0 and T1 in predicting survival.

METHODS

Consecutive patients (age ≥16 years) having B and T cell lymphoma who underwent SCT and who had PET/CT scan pre-SCT and 3 months post SCT were included in the study. A cross sectional image was analyzed at the level of the 3rd Lumber Vertebrae to assess body composition parameters.

RESULTS

93 patients [mean age: 38 (range: 17-70 years), 52 (55.9%) males, 45 (48%) Hodgkin and 48 (52%) Non-Hodgkin lymphoma, 81 (87%) autologous and 12 (13%) allogeneic SCT)] met the inclusion criteria. From T0 to T1, Sarcopenia rates increased (27% at T0 to 38% at T1, p = 0.013), Visceral adiposity decreased (46% at T0 to 30% at T1, p = 0.03) and SO decreased (42% at T0 to 20% at T1, p < 0.01). Length of stay, overall survival and progression free survival were significantly better in patients without sarcopenic obesity at T1. Cox-regression revealed SO at T1 was a risk factor for mortality [Adjusted Hazards Ratio = 8.2 (95% Confidence Interval: 1.9-36.2)].

CONCLUSION

Sarcopenic obesity, prevalent in 42% of patients pre-HSCT, decreased 3 months post HSCT as lymphoma patients lost skeletal muscle and visceral adipose tissues. SO at T1 was the most impactful risk factor for mortality.

Current technologies in body composition assessment: advantages and disadvantages

The interest in non-invasive methods of body composition assessment is on the rise in health care, especially because of its association with clinical outcomes. Technology has revolutionized our understanding of body composition abnormalities, clinical prognostication, and disease follow-up, but translation to bedside is limited, especially in terms of cost effectiveness. Computed tomography gained increased attention in cancer and sarcopenia studies, for instance. Other methods also have interesting features and applications, including bedside ultrasonography, bioelectrical impedance analysis, and dual x-ray absorptiometry. Compelling evidence indicates these methods can be used to accurately and precisely measure skeletal muscle mass, adipose tissue, and edema; diagnose malnutrition-related diseases; and aid in determining prognoses. To apply this technology properly, it is important to understand the advantages and disadvantages of each technique in specific situations of interest. This review introduces concepts and reference studies published in the scientific literature about these techniques and describes important limitations and considerations necessary to incorporate these methods into clinical practice.

Sarcopenia in Patients with Rheumatic Diseases: Prevalence and Associated Risk Factors

The prevalence of sarcopenia in rheumatic diseases has been evaluated in single diseases using various diagnostic approaches, generating conflicting data on the pathogenetic mechanism(s). Herein, we evaluated both muscle mass index (MMI) and muscle strength to assess sarcopenia and presarcopenia in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS). Moreover, we evaluated the possible impact of disease/patient-related characteristics, therapeutic regimens, and nutritional aspects on sarcopenia. The present study included 168 patients of both genders, aged 40⁻75 years. All patients underwent a nutritional evaluation, physical activity level assessment, rheumatologic evaluation, and an MMI and muscle strength assessment. The prevalence of sarcopenia was about 20% in all the three rheumatologic diseases, whereas presarcopenia was significantly different in RA, PsA and AS (p = 0.006). At multivariate analysis, only age ≥60 years and the presence of a disability were associated with a significantly increased risk of sarcopenia (p = 0.006 and p = 0.01, respectively), while a higher C-reactive protein did not reach statistical significance. Sarcopenia is similar in RA, PsA and AS, whereas presarcopenia significantly differs in these three diseases. Disease activity/inflammation and nutritional aspects do not influence sarcopenia, while age ≥60 years and the presence of a disability significantly increase the risk of sarcopenia.

The relationship between hypovitaminosis D and metabolic syndrome: a cross sectional study among employees of a private university in Lebanon

BACKGROUND

The prevalence of low vitamin D status and metabolic syndrome is increasing globally and in Lebanon. The objectives of this study are to assess the prevalence of metabolic syndrome (MetS) and its components (elevated triglycerides, low HDL, abdominal obesity defined by high waist circumference, hypertension, impaired fasting blood glucose) and investigate the association between serum 25-hydroxyvitamin D (25(OH)D) concentrations and MetS and its components among a sample of Lebanese adults.

METHODS

A cross-sectional study was carried out on Notre Dame University employees. A background questionnaire, a short-form of the International Physical Activity Questionnaire and a food frequency questionnaire were administered. Participants were invited to the nutrition laboratory to gather data on anthropometric (height, waist circumference, weight, body composition and body mass index) and biochemical measurements (serum vitamin D, triglycerides, HDL and fasting blood glucose). Vitamin D status was assessed according to the Institute of Medicine cut-offs (inadequate or adequate: 25(OH)D < or ≥ 50 nmol/L).The definition of the Third Report of the National Cholesterol Education Program was used to identify individuals who had MetS. The data were analyzed using the SPSS version 22. P < 0.05 was considered statistically significant.

RESULTS

A total of 344 participants (age range of 20 to 74 years) were included in the study. The prevalence of MetS was 23.5%. Among MetS components, central obesity was the most prevalent condition (50.6%), while the least prevalent was impaired fasting blood glucose (20.3%). The odds of having MetS were found to be 2.5 (95% CI 1.3-4.7) higher among those with inadequate vitamin D status, than among those with adequate vitamin D status while controlling for important confounders (age, marital status, education level, income, medical morbidity, smoking and percent body fat and gender). Among the components of MetS, only hypertriglyceridemia (OR: 2.4, 95%CI: 1.3-4.2) and low HDL (OR: 1.8, 95% CI: 1.0-3.0) were associated with inadequate vitamin D status while controlling for important confounders.

CONCLUSIONS

Early identification and control of risk factors for cardiovascular diseases in the primary care level is needed, particularly among adults who have low vitamin D status, are obese, and have low income level.

Revisiting the United States Army body composition standards: a receiver operating characteristic analysis

BACKGROUND

The objective for percent body fat standards in the United States Army Body Composition Program (ABCP) is to ensure soldiers maintain optimal well-being and performance under all conditions. However, conducting large-scale experiments within the United States Army to evaluate the efficacy of the thresholds is challenging.

METHODS

A receiver operating characteristic (ROC) analysis with corresponding area under the curve (AUC) was performed on body mass index (BMI) and waist circumference to determine optimal gender-specific age cohort thresholds that meet ABCP percent body fat standards in the National Health and Nutrition Examination Survey (NHANES) III. A second dataset consisting of a cohort of basic training recruits (N = 20,896 soldiers, 28% female) with BMI and waist circumference measured using a 3D body image scanner was applied to calculate what percent of basic training recruits meet the ABCP percent body fat standards. Regression models to determine the contribution of different circumference sites to the predictions of percent body fat were developed using a database compiled at the New York Obesity Research Center (N = 500).

RESULTS

Optimal BMI thresholds ranged from 23.65 kg/m² (17-21-year-old cohort) to 26.55 kg/m² (40 and over age cohort) for males and 21.75 to 24.85 kg/m² for females. The AUC values were between 0.86 and 0.92. The waist circumference thresholds ranged 81.35 to 97.55 cm for males and 77.05 to 89.35 cm for females with AUC values between 0.90 and 0.91. These BMI thresholds were exceeded by 65% of male and 74% of female basic training recruits and waist circumference thresholds were exceeded by 73% of male and 85% of female recruits. The single circumference that contributed most to prediction of body fat was waist circumference in males and mid-thigh circumference in females.

CONCLUSIONS

The ABCP percent body fat thresholds yield BMI thresholds that are below the United States Army BMI standards, especially in females which suggests the ABCP percent body fat standards may be too restrictive. The United States Army percent body fat standards could instead be matched to existing national health guidelines.

Sarcopenic obesity in older adults: aetiology, epidemiology and treatment strategies

The prevalence of obesity in combination with sarcopenia (the age-related loss of muscle mass and strength or physical function) is increasing in adults aged 65 years and older. A major subset of adults over the age of 65 is now classified as having sarcopenic obesity, a high-risk geriatric syndrome predominantly observed in an ageing population that is at risk of synergistic complications from both sarcopenia and obesity. This Review discusses pathways and mechanisms leading to muscle impairment in older adults with obesity. We explore sex-specific hormonal changes, inflammatory pathways and myocellular mechanisms leading to the development of sarcopenic obesity. We discuss the evolution, controversies and challenges in defining sarcopenic obesity and present current body composition modalities used to assess this condition. Epidemiological surveys form the basis of defining its prevalence and consequences beyond comorbidity and mortality. Current treatment strategies, and the evidence supporting them, are outlined, with a focus on calorie restriction, protein supplementation and aerobic and resistance exercises. We also describe weight loss-induced complications in patients with sarcopenic obesity that are relevant to clinical management. Finally, we review novel and potential future therapies including testosterone, selective androgen receptor modulators, myostatin inhibitors, ghrelin analogues, vitamin K and mesenchymal stem cell therapy.

Vitamin D status and body composition: a cross-sectional study among employees at a private university in Lebanon

Background

The prevalence of low vitamin D status is increasing globally, and Lebanon is not spared. The objectives of this study are to determine the prevalence and correlates of low vitamin D status, and to assess the association between percent body fat and vitamin D status, independently of obesity.

Methods

A cross-sectional study was performed on NDU employees. Data on dietary intake, physical activity, lifestyle, health status, and demographic variables were collected during a face-to-face interview. Anthropometric measures (weight, height and waist circumference) were measured and body composition was assessed using the bioelectrical impedance analysis (BIA) machine InBody 720 (Biospace, Seoul, Korea). The Nutritionist Pro diet analysis software version 31.0 was used to estimate dietary intake of vitamin D. Serum 25 hydroxyvitamin D (25(OH)D) was measured using enzyme linked immunosorbent assay kit (ELISA) (Calbiotech, Spring Valley, California, USA). Vitamin D status was assessed according to the National Osteoporosis Foundation (sufficiency: ≥ 75 nmol/L / ≥30 ng/mL) and the Institute of Medicine cut-offs (adequacy: ≥50 nmol/L / ≥20 ng/mL). Statistical analyses were performed by SPSS version 22.

Results

A total of 344 employees (50% Male) aged between 20 and 74 years participated in the study. More than half of the participants were overweight and obese. Mean serum vitamin D concentrations were 28.2 ± 13.9 ng/mL. Among participants, 37.5% of our study population had 25(OH)D ≥ 30 ng/mL, and 68.3% had 25(OH)D ≥ 20 ng/mL. Individuals with low vitamin D status had significantly higher percent body fat (PBF) (p < 0.005), and higher waist circumference (WC) (p = 0.012) than in the sufficient group, however BMI did not differ by vitamin D status. Logistic regression analysis indicated that a 1% increase in body fat increases the odds of having 25(OH)D ≤ 30 ng/mL by 8% while controlling for BMI and other confounders (p = 0.019).

Conclusion

This study reinforces the need for regular screening for low vitamin D status in Lebanese adults, particularly individuals at risk, including those with high risk WC, high PBF, who work indoors and have low vitamin D intake, and recommending vitamin D supplementation if needed.

Association of Energy and Protein Delivery on Skeletal Muscle Mass Changes in Critically Ill Adults: A Systematic Review

Critically ill patients experience significant and rapid loss of skeletal muscle mass, which has been associated with negative clinical outcomes. The aetiology of muscle wasting is multifactorial and nutrition delivery may play a role. A systematic literature review was conducted to examine the association of energy and/or protein provision on changes in skeletal muscle mass in critically ill patients. Key databases were searched up until March 2016 to identify studies that measured skeletal muscle mass and/or total body protein (TBP) at 2 or more time points during acute critical illness (up to 2 weeks after an intensive care unit [ICU] stay). Studies were included if there was documentation of participant energy balance or mean energy delivered to participants during the time period between body composition measurements. Six studies met inclusion criteria. A variety of methods were used to assess skeletal muscle mass or TBP. Participants in included studies experienced differing levels of muscle loss (0%-22.5%) during the first 2 weeks of ICU admission. No association between energy and protein delivery and changes in skeletal muscle mass were observed. This review highlights that there is currently limited high-quality evidence to clearly define the association between energy and/or protein delivery and skeletal muscle mass changes in acute critical illness. Future studies in this area should be adequately powered, account for all potential confounding factors to changes in skeletal muscle mass, and detail all sources and quantities of energy and protein delivered to participants.

Energy Intake Derived from an Energy Balance Equation, Validated Activity Monitors, and Dual X-Ray Absorptiometry Can Provide Acceptable Caloric Intake Data among Young Adults

Background

Assessments of energy intake (EI) are frequently affected by measurement error. Recently, a simple equation was developed and validated to estimate EI on the basis of the energy balance equation [EI = changed body energy stores + energy expenditure (EE)].

Objective

The purpose of this study was to compare multiple estimates of EI, including 2 calculated from the energy balance equation by using doubly labeled water (DLW) or activity monitors, in free-living adults.

Methods

The body composition of participants (n = 195; mean age: 27.9 y; 46% women) was measured at the beginning and end of a 2-wk assessment period with the use of dual-energy X-ray absorptiometry. Resting metabolic rate (RMR) was calculated through indirect calorimetry. EE was assessed with the use of the DLW technique and an arm-based activity monitor [Sensewear Mini Armband (SWA); BodyMedia, Inc.]. Self-reported EI was calculated by using dietitian-administered 24-h dietary recalls. Two estimates of EI were calculated with the use of a validated equation: quantity of energy stores estimated from the changes in fat mass and fat-free mass occurring over the assessment period plus EE from either DLW or the SWA. To compare estimates of EI, reporting bias (estimated EI/EE from DLW × 100) and Goldberg ratios (estimated EI/RMR) were calculated.

Results

Mean ± SD EEs from DLW and SWA were 2731 ± 494 and 2729 ± 559 kcal/d, respectively. Self-reported EI was 2113 ± 638 kcal/d, EI derived from DLW was 2723 ± 469 kcal/d, and EI derived from the SWA was 2720 ± 730 kcal/d. Reporting biases for self-reported EI, DLW-derived EI, and SWA-derived EI are as follows: -21.5% ± 22.2%, -0.7% ± 18.5%, and 0.2% ± 20.8%, respectively. Goldberg cutoffs for self-reported EI, DLW EI, and SWA EI are as follows: 1.39 ± 0.39, 1.77 ± 0.38, and 1.77 ± 0.38 kcal/d, respectively.

Conclusions

These results indicate that estimates of EI based on the energy balance equation can provide reasonable estimates of group mean EI in young adults. The findings suggest that, when EE derived from DLW is not feasible, an activity monitor that provides a valid estimate of EE can be substituted for EE from DLW.

Sarcopenic obesity: hidden muscle wasting and its impact for survival and complications of cancer therapy

Body composition, defined as the proportions and distribution of lean and fat tissues in the human body, is an emergent theme in clinical oncology. Severe muscle depletion (sarcopenia) is most easily overlooked in obese patients; the advent of secondary analysis of oncologic images provides a precise and specific assessment of sarcopenia. Here, we review the definitions, prevalence and clinical implications of sarcopenic obesity (SO) in medical and surgical oncology. Reported prevalence of SO varies due to the heterogeneity in the definitions and the variability in the cut points used to define low muscle mass and high fat mass. Prevalence of SO in advanced solid tumor patient populations average 9% (range 2.3%-14.6%) overall, and one in four (24.7%, range 5.9%-39.2%) patients with body mass index ≥ 30 kg/m2 are sarcopenic. SO is independently associated with higher mortality and higher rate of complications in systemic and surgical cancer treatment, across multiple cancer sites and treatment plans. These associations remain unexplained, however, it has been hypothesized that patients with sarcopenia are generally unfit and unable to tolerate stress. Another proposed mechanism relates to increased exposure to antineoplastic therapy, i.e. a large fat mass would be expected to inflate drug dose in BSA-based treatments, causing an increased rate of dose-limiting toxicity. Pharmacokinetic data are needed to confirm or refute this hypothesis. Old age, deconditioning, cancer progression, acute or chronic nonmalignant disease and drug side-effects are suggested causes of muscle loss, and it is unknown the degree to which this can be reversed. Sarcopenia can be readily detected before start of cancer treatment, however, clinical management protocols for SO patients require development. Studies of cancer treatment dose-modulation are in progress.

Prevalence and Predictors of Low Serum 25-Hydroxyvitamin D among Female African-American Breast Cancer Survivors

BACKGROUND

African-American breast cancer survivors commonly demonstrate low serum 25-hydroxyvitamin D (25(OH)D). Decreased cutaneous conversion, high levels of adiposity, and even breast cancer treatment may influence vitamin D status. Previous investigations have analyzed African-American women in aggregate with other breast cancer survivors and have not comprehensively addressed these influential factors.

OBJECTIVES

To determine the prevalence of low serum 25(OH)D in an exclusively African-American cohort of female breast cancer survivors with overweight/obesity and to evaluate the role of ultraviolet (UV) light exposure, body composition, and dietary sources of vitamin D on serum 25(OH)D levels.

DESIGN

Cross-sectional.

PARTICIPANTS

Pre- and postmenopausal African-American breast cancer survivors (n=244) were recruited from various neighborhoods in the city of Chicago, IL, between September 2011 and September 2014 for a larger weight loss trial.

MAIN OUTCOME MEASURES

Demographic, clinical, anthropometric (body mass index [calculated as kg/m²], waist circumference, and hip circumference), blood specimen, dietary intake (food frequency questionnaire), and sun behavior data were collected by trained study personnel before trial participation. Dual-energy x-ray absorptiometry was used to quantify adiposity (total, percentage, regional, visceral) and lean mass. Serum 25(OH)D was used as the biomarker reflective of vitamin D status.

STATISTICAL ANALYSES

Mean (±standard deviation), frequencies, and multivariate linear regression modeling.

RESULTS

The average participant was 57.4 years old (±10.0), 6.9 years (±5.2) from initial breast cancer diagnosis with a body mass index of 36.2 (±6.2). The majority of participants (60%) reported habitual oral vitamin D supplementation with mean intake of 327 IU (±169). Vitamin D deficiency was prevalent in 81% and 43%, when the cut points of the Endocrine Society (<30 ng/mL or <75 nmol/L) and the Institute of Medicine (<20 ng/mL or <50 nmol/L) were applied, respectively. A multivariate model adjusting for age, seasonality of blood draw, total energy intake, use of supplemental vitamin D, darker skin pigmentation, breast cancer stage, and waist-to-hip ratio was able to explain 28.8% of the observed variance in serum 25(OH)D concentrations. No significant associations were detected for body mass index or any dual-energy x-ray absorptiometry measures of body composition.

CONCLUSIONS

Considering the number of women who endorsed use of vitamin D supplementation, the prevalence of vitamin D deficiency among these African-American breast cancer survivors was high. Vitamin D supplementation, sun behavior, and waist-to-hip ratio may serve as future points of intervention to improve the vitamin D status of this minority survivor population.

Chiarello P. Estimation of Body Composition and Water Data Depends on the Bioelectrical Impedance Device

Overweight, obese and chronic kidney disease patients have an altered and negative body composition being its assessment important. Bioelectrical impedance analysis is an easy-to-operate and low-cost method for this purpose. This study aimed to compare and correlate data from single- and multi-frequency bioelectrical impedance spectroscopy applied in subjects with different body sizes, adiposity, and hydration status. It was a cross-sectional study with 386 non-chronic kidney disease volunteers (body mass index from 17 to 40 kg/m2), 30 patients in peritoneal dialysis, and 95 in hemodialysis. Bioelectrical impedance, body composition, and body water data were assessed with single- and multi-frequency bioelectrical impedance spectroscopy. Differences (95% confidence interval) and agreements (Bland-Atman analyze) between devices were evaluated. The intraclass correlation coefficient was used to measure the strength of agreement and Pearson's correlation to measure the association. Regression analyze was performed to test the association between device difference with body mass index and overhydration. The limits of agreement between devices were very large. Fat mass showed the greatest difference and the lowest intraclass and Pearson's correlation coefficients. Pearson's correlation varied from moderate to strong and the intraclass correlation coefficient from weak to substantial. The difference between devices were greater as body mass index increased and was worse in the extremes of water imbalance. In conclusion, data obtained with single- and multi-frequency bioelectrical impedance spectroscopy were highly correlated with poor agreement; the devices cannot be used interchangeably and the agreement between the devices was worse as body mass index and fat mass increased and in the extremes of overhydration.

Differences in skeletal muscle loss caused by cytotoxic chemotherapy and molecular targeted therapy in patients with advanced non-small cell lung cancer

BACKGROUND

Recent studies have revealed a reduction in the skeletal muscle area in patients with advanced non-small cell lung cancer (NSCLC) after chemotherapy. EGFR and ALK tyrosine kinase inhibitor (TKI)-based therapies are less cytotoxic than chemotherapy, but differences in skeletal muscle mass between patients receiving EGFR and ALK TKI therapies and patients receiving cytotoxic chemotherapy have not yet been reported.

METHODS

Data of pathologically proven NSCLC patients were reviewed, and chest computed tomography and/or positron emission tomography-computed tomography images obtained from January 2012 to December 2014 were selected. Patients were divided into two groups: cytotoxic chemotherapy (CG) and molecular targeted (MG). Muscle mass was measured with a single cross-sectional area of the muscle at the third lumber vertebra (L3MA). To estimate skeletal muscle changes during chemotherapy, we defined the following L3 skeletal muscle index (L3SMI) ratio: post L3SMI/pre L3SMI. Differences in the SMI ratio between the groups were evaluated using the Wilcoxon signed-rank test.

RESULTS

Sixty-five patients were included in this study: 44 patients received cytotoxic chemotherapy and 21 received molecular targeted therapy (EGFR and ALK TKI). The loss of L3MA in the CG was higher than in the MG (P = 0.03). In the CG, the L3SMI ratio defined to evaluate skeletal muscle mass changes was significantly lower than in the MG (P = 0.0188).

CONCLUSION

Our results suggest that skeletal muscle loss during first-line therapy was significantly different between patients receiving cytotoxic chemotherapy and those receiving TKIs. Specifically, skeletal muscle loss was lower in patients receiving TKIs than in patients receiving cytotoxic chemotherapy.

Creatine ( methyl-d3) dilution in urine for estimation of total body skeletal muscle mass: accuracy and variability vs. MRI and DXA

A noninvasive method to estimate muscle mass based on creatine ( methyl-d₃) (D₃-creatine) dilution using fasting morning urine was evaluated for accuracy and variability over a 3- to 4-mo period. Healthy older (67- to 80-yr-old) subjects ( n = 14) with muscle wasting secondary to aging and four patients with chronic disease (58-76 yr old) fasted overnight and then received an oral 30-mg dose of D₃-creatine at 8 AM ( day 1). Urine was collected during 4 h of continued fasting and then at consecutive 4- to 8-h intervals through day 5. Assessment was repeated 3-4 mo later in 13 healthy subjects and 1 patient with congestive heart failure. Deuterated and unlabeled creatine and creatinine were measured using liquid chromatography-tandem mass spectrometry. Total body creatine pool size and muscle mass were calculated from D₃-creatinine enrichment in urine. Muscle mass was also measured by whole body MRI and 24-h urine creatinine, and lean body mass (LBM) was measured by dual-energy X-ray absorptiometry (DXA). D₃-creatinine urinary enrichment from day 5 provided muscle mass estimates that correlated with MRI for all subjects ( r = 0.88, P < 0.0001), with less bias [difference from MRI = -3.00 ± 2.75 (SD) kg] than total LBM assessment by DXA, which overestimated muscle mass vs. MRI (+22.5 ± 3.7 kg). However, intraindividual variability was high with the D₃-creatine dilution method, with intrasubject SD for estimated muscle mass of 2.5 kg vs. MRI (0.5 kg) and DXA (0.8 kg). This study supports further clinical validation of the D₃-creatine method for estimating muscle mass. NEW & NOTEWORTHY Measurement of creatine ( methyl-d₃) (D₃-creatine) and D₃-creatinine excretion in fasted morning urine samples may be a simple, less costly alternative to MRI or dual-energy X-ray absorptiometry (DXA) to calculate total body muscle mass. The D₃-creatine enrichment method provides estimates of muscle mass that correlate well with MRI, and with less bias than DXA. However, intraindividual variability is high with the D₃-creatine method. Studies to refine the spot urine sample method for estimation of muscle mass may be warranted.

Body Composition Tools for Assessment of Adult Malnutrition at the Bedside: A Tutorial on Research Considerations and Clinical Applications

Because of the key role played by the body's lean tissue reserves (of which skeletal muscle is a major component) in the response to injury and illness, its maintenance is of central importance to nutrition status. With the recent development of the Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition diagnostic framework for malnutrition, the loss of muscle mass has been recognized as one of the defining criteria. Objective methods to evaluate muscle loss in individuals with acute and chronic illness are needed. Bioimpedance and ultrasound techniques are currently the best options for the clinical setting; however, additional research is needed to investigate how best to optimize measurements and minimize error and to establish if these techniques (and which specific approaches) can uniquely contribute to the assessment of malnutrition, beyond more subjective evaluation methods. In this tutorial, key concepts and statistical methods used in the validation of bedside methods to assess lean tissue compartments are discussed. Body composition assessment methods that are most widely available for practice and research in the clinical setting are presented, and clinical cases are used to illustrate how the clinician might use bioimpedance and/or ultrasound as a tool to assess nutrition status at the bedside. Future research needs regarding malnutrition assessment are identified.

New specific bioelectrical impedance vector reference values for assessing body composition in the Italian-Spanish young adult population

OBJECTIVE

Specific bioelectrical impedance vector analysis (spBIVA) is a recently proposed technique for the analysis of body composition. The aim of this study was to apply spBIVA to a sample of Italian and Spanish young adults and to define the new bioelectrical references for this Western Mediterranean population.

METHODS

A sample of 440 individuals (220 from Italy, 220 from Spain; 213 men, 227 women) aged 18-30 years was considered. Anthropometric (height, weight, relaxed upper arm, waist, and calf girths) and bioelectrical (resistance, reactance; 50 kHz, 800 μA) measurements were taken. In order to verify the need for new references, specific bioelectrical values were compared to the reference values for U.S. adults and Italian elderly by tolerance ellipses and Student's t test.

RESULTS

The mean specific bioelectrical values (resistivity, Rsp, and reactivity, Xcsp, Ohm·cm) were: Rsp (332.7 ± 41.7 Ω·cm), Xcsp (44.4 ± 6.8 Ω·cm), Zsp (335.6 ± 41.9 Ω·cm) and phase (7.6 ± 0.8°) in men; Rsp (388.6 ± 60 Ω·cm), Xcsp (43.7 ± 7.5 Ω·cm), Zsp (391.0 ± 60.3 Ω·cm) and phase (6.4 ± 0.7°) in women. Italo-Spanish bioelectrical vectors were mainly distributed (>90%) in the lower part of the tolerance ellipses for U.S. young adults, due to a shorter impedance (P < 0.001), indicative of a lower percent fat mass. Compared to Italian elders, they were mainly located in the left side (>90%), due to a higher phase (P < 0.001), indicative of higher body cell mass.

CONCLUSIONS

These population and age-related differences indicate the need for new specific tolerance ellipses that can be used as references for assessing body composition in young adults from Western Mediterranean populations.

Measurement of body composition as a surrogate evaluation of energy balance in obese patients

In clinical practice obesity is primarily diagnosed through the body mass index. In order to characterize patients affected by obesity the use of traditional anthropometric measures appears misleading. Beyond the body mass index, there are overwhelming evidences towards the relevance of a more detailed description of the individual phenotype by characterizing the main body components as free-fat mass, muscle mass, and fat mass. Among the numerous techniques actually available, bioelectrical impedance analysis seems to be the most suitable in a clinical setting because it is simple, inexpensive, noninvasive, and highly reproducible. To date, there is no consensus concerning the use of one preferred equation for the resting energy expenditure in overweight and/or obese population. Energy restriction alone is an effective strategy to achieve an early and significant weight loss, however it results in a reduction of both fat and lean mass therefore promoting or aggravating an unfavourable body composition (as sarcobesity) in terms of mortality and comorbidities. Therefore the implementation of daily levels of physical activity should be simultaneously promoted. The major role of muscle mass in the energy balance has been recently established by the rising prevalence of the combination of two condition as sarcopenia and obesity. Physical exercise stimulates energy expenditure, thereby directly improving energy balance, and also promotes adaptations such as fiber type, mitochondrial biogenesis, improvement of insulin resistance, and release of myokines, which may influence different tissues, including muscle.

Changes in skeletal muscle mass during palliative chemotherapy in patients with advanced lung cancer

BACKGROUND

Sarcopenia is a defining feature of cancer cachexia associated with physical decline, poor quality of life and poor prognosis. Thus, maintaining muscle mass is an important aim of cachexia treatment. Many patients at risk for developing cachexia or with cachexia experience side effects of chemotherapy that might aggravate the development of cachexia. However, achieving tumor control might reverse the catabolic processes causing cachexia. There is limited knowledge about muscle mass changes during chemotherapy or whether changes in muscle mass are associated with response to chemotherapy.

PATIENTS AND METHODS

In this pilot study, patients with advanced non-small cell lung cancer (NSCLC) receiving three courses of palliative chemotherapy were analyzed. Muscle mass was measured as skeletal muscle cross sectional area (SMCA) at the level of the third lumbar vertebrae using CT images taken before and after chemotherapy.

RESULTS

In total 35 patients, 48% women, mean age 67 years (range 56-86), participated; 83% had stage IV disease and 71% were sarcopenic at baseline. Mean reduction in SMCA from pre- to post-chemotherapy was 4.6 cm2 (CI 95% -7.3--1.9; p<0.002), corresponding to a 1.4 kg loss of whole body muscle mass. Sixteen patients remained stable or gained SMCA. Of these, 14 (56%) responded to chemotherapy, while two progressed (p=0.071). Maintaining or gaining SMCA resulted in longer median overall survival (loss: 5.8 months, stable/gain: 10.7 months; p=0.073). Stage of disease (p=0.003), treatment regimen (p=0.023), response to chemotherapy (p=0.007) and SMCA change (p=0.040), but not sarcopenia at baseline, were significant prognostic factors in the multivariate survival analyses.

CONCLUSION

Almost half of the patients had stable or increased muscle mass during chemotherapy without receiving any cachexia treatment. Nearly all of these patients responded to the chemotherapy. Increase in muscle mass, but not sarcopenia at baseline, was a significant prognostic factor.

An objective estimate of energy intake during weight gain using the intake-balance method

BACKGROUND

Estimates of energy intake (EI) in humans have limited validity.

OBJECTIVE

The objective was to test the accuracy and precision of the intake-balance method to estimate EI during weight gain induced by overfeeding.

DESIGN

In 2 studies of controlled overfeeding (1 inpatient study and 1 outpatient study), baseline energy requirements were determined by a doubly labeled water study and caloric titration to weight maintenance. Overfeeding was prescribed as 140% of baseline energy requirements for 56 d. Changes in weight, fat mass (FM), and fat-free mass (FFM) were used to estimate change in energy stores (ΔES). Overfeeding EI was estimated as the sum of baseline energy requirements, thermic effect of food, and ΔES. The estimated overfeeding EI was then compared with the actual EI consumed in the metabolic chamber during the last week of overfeeding.

RESULTS

In inpatient individuals, calculated EI during overfeeding determined from ΔES in FM and FFM was (mean ± SD) 3461 ± 848 kcal/d, which was not significantly (-29 ± 273 kcal/d or 0.8%; limits of agreement: -564, 505 kcal/d; P = 0.78) different from the actual EI provided (3490 ± 729 kcal/d). Estimated EI determined from ΔES in weight closely estimated actual intake (-7 ± 193 kcal/d or 0.2%; limits of agreement: -386, 370 kcal/d; P = 0.9). In free-living individuals, estimated EI during overfeeding determined from ΔES in FM and FFM was 4123 ± 500 kcal/d and underestimated actual EI (4286 ± 488 kcal/d; -162 ± 301 kcal or 3.8%; limits of agreement: -751, 427 kcal/d; P = 0.003). Estimated EI determined from ΔES in weight also underestimated actual intake (-159 ± 270 kcal/d or 3.7%; limits of agreement: -688, 370 kcal/d; P = 0.001).

CONCLUSION

The intake-balance method can be used to estimate EI during a period of weight gain as a result of 40% overfeeding in individuals who are inpatients or free-living with only a slight underestimate of actual EI by 0.2-3.8%.

Functional body composition and related aspects in research on obesity and cachexia: report on the 12th Stock Conference held on 6 and 7 September 2013 in Hamburg, Germany

The 12th Stock Conference addressed body composition and related functions in two extreme situations, obesity and cancer cachexia. The concept of 'functional body composition' integrates body components into regulatory systems relating the mass of organs and tissues to corresponding in vivo functions and metabolic processes. This concept adds to an understanding of organ/tissue mass and function in the context of metabolic adaptations to weight change and disease. During weight gain and loss, there are associated changes in individual body components while the relationships between organ and tissue mass are fixed. Thus an understanding of body weight regulation involves an examination of the relationships between organs and tissues rather than individual organ and tissue masses only. The between organ/tissue mass relationships are associated with and explained by crosstalks between organs and tissues mediated by cytokines, hormones and metabolites that are coupled with changes in body weight, composition and function as observed in obesity and cancer cachexia. In addition to established roles in intermediary metabolism, cell function and inflammation, organ-tissue crosstalk mediators are determinants of body composition and its change with weight gain and loss. The 12th Stock Conference supported Michael Stocks' concept of gaining new insights by integrating research ideas from obesity and cancer cachexia. The conference presentations provide an in-depth understanding of body composition and metabolism.

Concurrent evolution of cancer cachexia and heart failure: bilateral effects exist

Cancer cachexia is defined as a multifactorial syndrome of involuntary weight loss characterized by an ongoing loss of skeletal muscle mass and progressive functional impairment. It is postulated that cardiac dysfunction/atrophy parallels skeletal muscle atrophy in cancer cachexia. Cardiotoxic chemotherapy may additionally result in cardiac dysfunction and heart failure in some cancer patients. Heart failure thus may be a consequence of either ongoing cachexia or chemotherapy-induced cardiotoxicity; at the same time, heart failure can result in cachexia, especially muscle wasting. Therefore, the subsequent heart failure and cardiac cachexia can exacerbate the existing cancer-induced cachexia. We discuss these bilateral effects between cancer cachexia and heart failure in cancer patients. Since cachectic patients are more susceptible to chemotherapy-induced toxicity overall, this may also include increased cardiotoxicity of antineoplastic agents. Patients with cachexia could thus be doubly unfortunate, with cachexia-related cardiac dysfunction/heart failure and increased susceptibility to cardiotoxicity during treatment. Cardiovascular risk factors as well as pre-existing heart failure seem to exacerbate cardiac susceptibility against cachexia and increase the rate of cardiac cachexia. Hence, chemotherapy-induced cardiotoxicity, cardiovascular risk factors, and pre-existing heart failure may accelerate the vicious cycle of cachexia-heart failure. The impact of cancer cachexia on cardiac dysfunction/heart failure in cancer patients has not been thoroughly studied. A combination of serial echocardiography for detection of cachexia-induced cardiac remodeling and computed tomography image analysis for detection of skeletal muscle wasting would appear a practical and non-invasive approach to develop an understanding of cardiac structural/functional alterations that are directly related to cachexia.

Efficacy of Resistance Training as an Aid to Smoking Cessation: Rationale and Design of the Strength To Quit Study

Despite recent declines in the rates of cigarette smoking, smoking remains prevalent among individuals with lower income, less education, and those with mental illness or HIV. Exercise is promoted as an aid to smoking cessation; however, the evidence for this recommendation is equivocal. To date, the majority of studies have only examined aerobic exercise; there is a poor understanding of the mechanisms of action; and there is an under-representation of male smokers. The goal of this trial is to produce new data that will help to address each of these gaps. A total of 206 male and female smokers will receive a brief smoking cessation education session prior to being randomized into a 12-week Resistance Training (RT) or Wellness Contact Control group. Both groups will have the option of using nicotine replacement therapy (NRT), and both will meet on-site twice per week during the 12-week program (24 total sessions). Follow-up assessments will occur at the end of the 12-weeks (3-month), and at a 6-month and 12-month (post-randomization) visit. Participants will not receive any additional smoking cessation treatment during follow-up; however, the RT group will receive a 9-month membership to a fitness center to encourage continued resistance training as a way to maintain cessation, and attendance will be tracked. The primary outcome is salivary-cotinine-verified 7-Day Point Prevalence Abstinence (PPA) at the 3-month assessment, and at the 6 and 12-month follow-ups. Secondary outcomes include effects of resistance training on nicotine withdrawal symptoms, indicators of mental health, and markers of disease risk.

Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans

Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19-30 yr, 70-84 yr), 15 postmenopausal women (51-62 yr, 70-84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA.

Weight loss composition is one-fourth fat-free mass: a critical review and critique of this widely cited rule

Maximizing fat loss while preserving lean tissue mass and function is a central goal of modern obesity treatments. A widely cited rule guiding expected loss of lean tissue as fat-free mass (FFM) states that approximately one-fourth of weight loss will be FFM (i.e. ΔFFM/ΔWeight = ∼0.25), with the remaining three-fourths being fat mass. This review examines the dynamic relationships between FFM, fat mass and weight changes that follow induction of negative energy balance with hypocaloric dieting and/or exercise. Historical developments in the field are traced with the 'Quarter FFM Rule' used as a framework to examine evolving concepts on obesity tissue, excess weight and what is often cited as 'Forbes' Rule'. Temporal effects in the fractional contribution of FFM to changes in body weight are examined as are lean tissue moderating effects such as ageing, inactivity and exercise that frequently accompany structured low-calorie diet weight loss protocols. Losses of lean tissue with dieting typically tend to be small, raising questions about study design, power and applied measurement method reliability. Our review elicits important questions related to the fractional loss of lean tissues with dieting and provides a foundation for future research on this topic.

Evolution of bioimpedance: a circuitous journey from estimation of physiological function to assessment of body composition and a return to clinical research

BACKGROUND/OBJECTIVES

Bioimpedance is the collective term that describes safe, non-invasive methods to measure the electrical responses to the introduction of a low-level, alternating current into a living organism, and the biophysical models to estimate body composition from bioelectrical measurements. Although bioimpedance techniques have been used for more than 100 years to monitor assorted biological components, the desire to translate bioelectrical measurements into physiological variables advanced the creation of empirical prediction models that produced inconsistent results.

SUBJECTS/METHODS

This paper succinctly reviews the origin, and critically evaluates the conceptual models and the implementation of bioimpedance in clinical research, including indirect assessment of assorted physiological functions and body composition (fluid volumes and fat-free mass), classification of hydration, regional fluid accumulation, prognosis in disease and wound healing.

RESULTS

Despite widespread and mounting interest in the use of bioimpedance to characterise body structure and function, most experimental findings reveal the limitations of existing physical models and reliance on multiple regression models for use in assessments of an individual.

CONCLUSIONS

Contemporary applications of bioimpedance emphasise the value of bioimpedance variables per se in some novel biomedical applications with the objective of identifying opportunities for future outcome-based research.

What makes a BIA equation unique? Validity of eight-electrode multifrequency BIA to estimate body composition in a healthy adult population

BACKGROUND/OBJECTIVES

The validity of bioelectrical impedance analysis (BIA) for body composition analysis is limited by assumptions relating to body shape. Improvement in BIA technology could overcome these limitations and reduce the population specificity of the BIA algorithm.

SUBJECTS/METHODS

BIA equations for the prediction of fat-free mass (FFM), total body water (TBW) and extracellular water (ECW) were generated from data obtained on 124 Caucasians (body mass index 18.5-35 kg/m(2)) using a four-compartment model and dilution techniques as references. The algorithms were validated in an independent multiethnic population (n=130). The validity of BIA results was compared (i) between ethnic groups and (ii) with results from the four-compartment model and two-compartment methods (air-displacement plethysmography, dual-energy X-ray absorptiometry and deuterium dilution).

RESULTS

Indices were developed from segmental R and Xc values to represent the relative contribution of trunk and limbs to total body conductivity. The coefficient of determination for all prediction equations was high (R(2): 0.94 for ECW, 0.98 for FFM and 0.98 for TBW) and root mean square error was low (1.9 kg for FFM, 0.8 l for ECW and 1.3 kg for TBW). The bias between BIA results and different reference methods was not statistically different between Afro-American, Hispanic, Asian or Caucasian populations and showed a similar difference (-0.2-0.2 kg FFM) when compared with the bias between different two-compartment reference methods (-0.2-0.3 kg FFM).

CONCLUSIONS

An eight-electrode, segmental multifrequency BIA is a valid tool to estimate body composition in healthy euvolemic adults compared with the validity and precision of other two-compartment reference methods. Population specificity is of minor importance when compared with discrepancies between different reference methods.

Beyond the body mass index: tracking body composition in the pathogenesis of obesity and the metabolic syndrome

Body composition is related to various physiological and pathological states. Characterization of individual body components adds to understand metabolic, endocrine and genetic data on obesity and obesity-related metabolic risks, e.g. insulin resistance. The obese phenotype is multifaceted and can be characterized by measures of body fat, leg fat, liver fat and skeletal muscle mass rather than by body mass index. The contribution of either whole body fat or fat distribution or individual fat depots to insulin resistance is moderate, but liver fat has a closer association with (hepatic) insulin resistance. Although liver fat is associated with visceral fat, its effect on insulin resistance is independent of visceral adipose tissue. In contrast to abdominal fat, appendicular or leg fat is inversely related to insulin resistance. The association between 'high fat mass + low muscle mass' (i.e. 'sarcopenic adiposity') and insulin resistance deserves further investigation and also attention in daily clinical practice. In addition to cross-sectional data, longitudinal assessment of body composition during controlled under- and overfeeding of normal-weight healthy young men shows that small decreases and increases in fat mass are associated with corresponding decreases and increases in insulin secretion as well as increases and decreases in insulin sensitivity. However, even under controlled conditions, there is a high intra- and inter-individual variance in the changes of (i) body composition; (ii) the 'body composition-glucose metabolism relationship' and (iii) glucose metabolism itself. Combining individual body components with their related functional aspects (e.g. the endocrine, metabolic and inflammatory profiles) will provide a suitable basis for future definitions of a 'metabolically healthy body composition'.

Sarcopenia is associated with postoperative infection and delayed recovery from colorectal cancer resection surgery

Background:

Skeletal muscle depletion (sarcopenia) predicts morbidity and mortality in the elderly and cancer patients.

Methods:

We tested whether sarcopenia predicts primary colorectal cancer resection outcomes in stage II–IV patients (n=234). Sarcopenia was assessed using preoperative computed tomography images. Administrative hospitalisation data encompassing the index surgical admission, direct transfers for inpatient rehabilitation care and hospital re-admissions within 30 days was searched for International Classification of Disease (ICD)-10 codes for postoperative infections and inpatient rehabilitation care and used to calculate length of stay (LOS).

Results:

Overall, 38.9% were sarcopenic; 16.7% had an infection and 9.0% had inpatient rehabilitation care. Length of stay was longer for sarcopenic patients overall (15.9±14.2 days vs 12.3±9.8 days, P=0.038) and especially in those ⩾65 years (20.2±16.9 days vs 13.1±8.3 days, P=0.008). Infection risk was greater for sarcopenic patients overall (23.7% vs 12.5% P=0.025), and especially those ⩾65 years (29.6% vs 8.8%, P=0.005). Most (90%) inpatient rehabilitation care was in patients ⩾65 years. Inpatient rehabilitation was more common in sarcopenic patients overall (14.3% vs 5.6% P=0.024) and those ⩾65 years (24.1% vs 10.7%, P=0.06). In a multivariate model in patients ⩾65 years, sarcopenia was an independent predictor of both infection (odds ratio (OR) 4.6, (95% confidence interval (CI) 1.5, 13.9) P<0.01) and rehabilitation care (OR 3.1 (95% CI 1.04, 9.4) P<0.04).

Conclusion:

Sarcopenia predicts postoperative infections, inpatient rehabilitation care and consequently a longer LOS.

Energy content of weight loss: kinetic features during voluntary caloric restriction

The classic rule stating that restricting intake by 3500 kcal/wk will lead to a 1-lb/wk rate of weight loss has come under intense scrutiny. Generally not a component of most weight loss prediction models, the "early" rapid weight loss phase may represent a period during which the energy content of weight change (ΔEC/ΔW) is low and thus does not follow the classic "rule." The current study tested this hypothesis. Dynamic ΔEC/ΔW changes were examined in 23 Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Study overweight men and women evaluated by dual-energy x-ray absorptiometry during weight loss at treatment weeks 4 to 24. Changes from baseline in body energy content were estimated from fat and fat-free mass. Repeated-measures analysis of variance was used to determine if ΔEC/ΔW changed significantly over time. The evaluation was expanded with addition of the Kiel 13-week weight loss study of 75 obese men and women to test with adequate power if there are sex differences in ΔEC/ΔW. The analysis of variance CALERIE time effect was significant (P < .001), with post hoc tests indicating that ΔEC/ΔW (kilocalories per kilogram) increased significantly from week 4 (X ± SEM; 4, 858 ± 388) to 6 (6, 041 ± 376, P < .01) and changed insignificantly thereafter; ΔEC/ΔW was significantly larger for Kiel women (6, 804 ± 226) vs men (6, 119 ± 240, P < .05). Sex-specific dynamic relative changes in body composition and related ΔEC/ΔW occur with weight loss initiation that extend for 1 month or more. These observations provide new information for developing energy balance models and further define limitations of the 3500-kcal energy deficit → 1-lb weight loss rule.