Differences among skeletal muscle mass indices derived from height-, weight-, and body mass index-adjusted models in assessing sarcopenia

Nutrition in Chronic Liver Disease: Consensus Statement of the Indian National Association for Study of the Liver

Malnutrition and sarcopenia are common in patients with chronic liver disease and are associated with increased risk of decompensation, infections, wait-list mortality and poorer outcomes after liver transplantation. Assessment of nutritional status and management of malnutrition are therefore essential to improve outcomes in patients with chronic liver disease. This consensus statement of the Indian National Association for Study of the Liver provides a comprehensive review of nutrition in chronic liver disease and gives recommendations for nutritional screening and treatment in specific clinical scenarios of malnutrition in cirrhosis in adults as well as children with chronic liver disease and metabolic disorders.

Normalizing calf circumference to identify low skeletal muscle mass in older women: a cross-sectional study

Introduction

Introduction: functional limitation is a result of sarcopenia and is associated with loss of skeletal muscle mass (SMM). Cost-effective methods are important for the identification of sarcopenia. Objective: to propose cutoff points for normalized calf circumference (CC) in order to identify low SMM in older women based on their functional limitation. Methods: in this descriptive, cross-sectional study the CC values of a young female sample (n = 78) were used to establish cutoff points (-2 SD) for low SMM in older women (n = 67). Functional limitation was identified by the six-minute walk test (≤ 400 m). CC was normalized by body mass, height, and BMI. The diagnostic accuracy of CC was calculated with a ROC curve, using functional limitation as standard. Results: cutoff points and area under the curve (AUC) were: CC (≤ 28.5; 0.62); CC·body mass-1 (≤ 0.40; 0.63); CC·height-2 (≤ 8.52; 0.55) and CC·BMI-1 (≤ 1.10; 0.73). Only CC·BMI-1 achieved a desirable accuracy (AUC > 0.7) to distinguish functional limitation. Conclusion: the accuracy attained supports the use of CC·BMI-1 to identify low SMM in older women. In the clinical context it is possible to predict the risk of sarcopenia when sophisticated methods for determining SMM are not available.

Association between Skeletal Mass Indices and Metabolic Syndrome in Brazilian Adults

INTRODUCTION

Skeletal muscle is the primary site of glucose uptake and its reduction would increase insulin resistance, which is a determinant factor for diseases such as type 2 diabetes mellitus, hypertension, and metabolic syndrome. However, the role of low skeletal muscle mass as a risk factor for metabolic syndrome and its association with cardiometabolic risk is still uncertain. We aimed to investigate the association between muscle mass (determined by different skeletal mass indices) and metabolic syndrome in Brazilian adults.

METHODOLOGY

We conducted a cross-sectional population-based study with 689 adults of both sexes aged between 20 and 59 years. Data were collected through questionnaires and assessment of body composition through dual-energy X-ray absorptiometry and anthropometric, clinical, and biochemical measurements.

RESULTS

Older individuals, obese and those with metabolic syndrome predominated in the highest tertile of skeletal mass index adjusted by height (SMI_height), whereas using skeletal mass index adjusted by weight (SMI_weight) and skeletal mass index adjusted by body mass index (SMI_BMI) these individuals were the majority in the lowest tertile of these indices. In men and women, the adjusted logistic regression model revealed that the highest tertile of SMI_weight (odds ratio [OR]: 0.06; 95% confidence interval [CI]: 0.02-0.21 and OR: 0.27, 95% CI: 0.10-0.74) and SMI_BMI (OR: 0.14, 95% CI: 0.05-0.37 and OR: 0.34, 95% CI: 0.12-0.94) were negatively associated with metabolic syndrome. On the other hand, the highest tertile of SMI_height was positively associated with metabolic syndrome in both sexes (OR: 4.17, 95% CI: 1.80-9.66 and OR: 6.15, 95% CI: 2.31-16.37, respectively in men and women).

CONCLUSION

In adults, the muscle mass assessed from the skeletal mass index adjusted for body weight and body mass index is inversely associated with metabolic syndrome in both sexes.

Novel approaches to sarcopenic obesity and weight management before and after kidney transplantation

PURPOSE OF REVIEW

Although a widely recognized and complex pathophysiological condition, sarcopenic obesity remains less appreciated and may elude diagnosis and workup in both kidney transplant waitlisted candidates and kidney transplant recipients. The lack of consensus definition, and practical diagnostic tools for evaluating waitlisted candidates and transplant recipients are barriers to early detect and initiate therapeutic management for sarcopenic obesity. Although sarcopenia leads to poor clinical outcomes, posttransplant obesity yields conflicting results. Exercise and nutritional managements are common therapies for sarcopenic obese patients; however, surgery weight loss or bariatric surgery in both transplant candidates and potential living kidney donors shows promising benefits for kidney transplant access in waitlist obese candidates but may require to be selected for appropriate patients.

RECENT FINDINGS

Pathogenesis and management for sarcopenia and obesity are interconnected. The benefits of exercise to improve muscle mass and function is clear in waitlist kidney transplant candidates and transplant recipients. However, there are several barriers for those to increase exercise and improve physical activity including patient, provider, and healthcare or environmental factors. The advantages of fat mass reduction to lose weight can promote muscle mass and strength. However, epidemiological data regarding the obesity paradox in dialysis-dependent patients when overnutrition provides survival benefits for this population should be taken into account when performing weight loss especially bariatric surgery.

SUMMARY

Barriers in providing optimal care to kidney transplant waitlisted candidates and transplant recipients may partly result from underdiagnosis of sarcopenic obesity; notwithstanding that this entity has increasingly been more recognized. Mechanistic studies to better understand pathogenesis of sarcopenic obesity will help determine pathogenesis and clinical tools for diagnosis of this entity, which can facilitate further studies related to the outcomes and weight management to ultimately improve kidney transplant outcomes.

Normalized Hand Grip and Back Muscle Strength as Risk Factors for Incident Type 2 Diabetes Mellitus: 16 Years of Follow-Up in a Population-Based Cohort Study

PURPOSE

Muscle strength is associated with type 2 diabetes mellitus (T2DM). However, it is controversial whether muscle strength and normalized muscle strength is a risk factor for T2DM. Moreover, the relationship of back muscle strength (BMS) and incident T2DM has not been reported. In this study, we investigated the relationship between HGS, BMS, normalized HGS and BMS, and incident T2DM.

METHODS

A total of 2699 non-diabetes subjects aged 40-69 years (1313 women and 1386 men) in the Korean Genome and Epidemiology Study (KoGES) Ansan cohort were followed for 16 years. At the baseline and biennial follow-up visits, fasting glucose, postprandial 2-h glucose, clinical examinations, HGS, and BMS were measured by trained interviewers and examiners. HGS and BMS were measured at baseline. The relationships between incident T2DM, HGS, BMS, and normalized HGS and BMS were estimated using Cox proportional hazard regression models after adjusting for the confounding factors.

RESULTS

HGS and BMS were not associated with incident T2DM in multivariate analysis. However, the hazard ratio (HR) per one standard deviation (SD) increase in the body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR)-normalized HGS, and BMS was associated with a lower risk for incident T2DM in both women and men after adjusting for the confounding factors (HR = 0.842-0.880-fold for women, p ≤ 0.015; HR = 0.887-0.903-fold for men, p ≤ 0.024). In the sub-analysis of menopause status, the HR per one SD increase in BMI, weight^2/3, WC, and WHR-normalized HGS was associated with a lower risk for incident T2DM in both pre- and post-menopausal women after adjusting for the confounding factors (HR = 0.860-0.820-fold for premenopausal, P ≤ 0.006; HR = 0.900-0.867-fold for postmenopausal, p ≤ 0.024). Additionally, we confirmed that the quartile group with higher muscle strength was associated with a lower risk for incident T2DM.

CONCLUSION

The present study suggested that normalized HGS and BMS were associated with a lower risk for the future development of T2DM. Moreover, weak muscle strength in premenopausal women may be the cause of T2DM. Further research is needed to determine whether efforts to improve muscle strength, such as exercise can reduce the risk of T2DM.

Ninjin'yoeito Ameliorates Skeletal Muscle Complications in COPD Model Mice by Upregulating Peroxisome Proliferator-Activated Receptor γ Coactivator-1α Expression

Purpose

Sarcopenia, the loss of skeletal muscle mass and strength, is a common systemic consequence of chronic obstructive pulmonary disease (COPD) and is correlated with higher mortality. Ninjin’yoeito (NYT) is a Japanese herbal medicine used to treat athrepsia and anorexia and is reported to ameliorate weight loss and muscular dysfunction. Recent studies have shown that its crude components upregulate the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α)-related pathway, which is involved in skeletal muscle functions. Here, we examined whether NYT improves skeletal muscle complications by upregulating PGC-1α in COPD model mice.

Materials and Methods

Mice were divided into four groups: control, NYT, smoking, and smoking + NYT. The smoking and smoking + NYT groups were exposed to cigarette smoke for 60 min once daily. The mice in the NYT and smoking + NYT groups were fed an NYT-containing diet (3% w/w). We performed cellular analysis of bronchoalveolar lavage fluid, assessed pulmonary morphological changes, examined the expression of PGC-1α mRNA and protein in the gastrocnemius and soleus muscle, measured the hindlimb muscle volume with micro-computed tomography, and determined the myofiber proportion in soleus muscle after 12 weeks.

Results

Cigarette smoke exposure resulted in reduced skeletal muscle volume and slow-twitch muscle fibers and development of pulmonary emphysema. NYT feeding induced partial recovery of the damaged alveolar wall; however, NYT did not ameliorate smoke-induced alveolar enlargement. These findings revealed that NYT did not have sufficient efficacy in suppressing pulmonary emphysema. On the other hand, PGC-1α expression in muscle tissue of the NYT-fed mice increased significantly, resulting in suppression of smoke-induced loss of muscle mass and alteration in the muscle fiber distribution.

Conclusion

NYT increases PGC-1α expression in the muscle of COPD model mice and is involved in suppressing cigarette smoke-induced muscle complications. NYT may be a novel preventive and therapeutic medication for muscular dysfunctions in COPD.

Sarcopenia: Clinical implications in ovarian cancer, diagnosis, etiology, and management

Sarcopenia, loss of skeletal muscle and function, is a common condition among the elderly and is known to cause adverse health outcomes and increased risk of morbidity and mortality. This progressive and generalized disorder imposes a considerable socioeconomic burden. Sarcopenia is observed commonly in cancer patients. As Asia is one of the fastest aging regions in the world, it is clear that incidences of both sarcopenia and ovarian cancer will increase together in Asian countries. Ovarian cancer patients are vulnerable to develop sarcopenia during the treatment course and progress of disease, and a considerable number of patients with ovarian cancer seems to have physical inactivity and sarcopenia already at the time of diagnosis. Therefore, management of sarcopenia should be conducted together in parallel with ovarian cancer treatment and surveillance. Thus, in this article, we will review the clinical importance of sarcopenia in the aspect of ovarian cancer. Definition of sarcopenia, diagnosis, etiology, and intervention will be also introduced.

Current understanding of glucose transporter 4 expression and functional mechanisms

Glucose is used aerobically and anaerobically to generate energy for cells. Glucose transporters (GLUTs) are transmembrane proteins that transport glucose across the cell membrane. Insulin promotes glucose utilization in part through promoting glucose entry into the skeletal and adipose tissues. This has been thought to be achieved through insulin-induced GLUT4 translocation from intracellular compartments to the cell membrane, which increases the overall rate of glucose flux into a cell. The insulin-induced GLUT4 translocation has been investigated extensively. Recently, significant progress has been made in our understanding of GLUT4 expression and translocation. Here, we summarized the methods and reagents used to determine the expression levels of Slc2a4 mRNA and GLUT4 protein, and GLUT4 translocation in the skeletal muscle, adipose tissues, heart and brain. Overall, a variety of methods such real-time polymerase chain reaction, immunohistochemistry, fluorescence microscopy, fusion proteins, stable cell line and transgenic animals have been used to answer particular questions related to GLUT4 system and insulin action. It seems that insulin-induced GLUT4 translocation can be observed in the heart and brain in addition to the skeletal muscle and adipocytes. Hormones other than insulin can induce GLUT4 translocation. Clearly, more studies of GLUT4 are warranted in the future to advance of our understanding of glucose homeostasis.

Comparison of the associations between appendicular lean mass adjustment methods and cardiometabolic factors

BACKGROUND AND AIMS

To compare the cross-sectional and longitudinal associations between appendicular lean mass (ALM) and cardiometabolic risk factors according to body-size adjustment methods and the contributions of genetic and/or environmental factors to the correlations between those traits.

METHODS AND RESULTS

Regression coefficients per sex-specific 1 standard deviation in bodyweight (wt), body mass index (BMI), or height-squared (ht²) adjusted ALM (assessed using a dual-energy X-ray absorptiometer (DXA) and a bioelectrical impedance analyzer (BIA) at baseline)/changes in these indices (assessed using BIA) were compared in terms of their associations with blood pressure (BP), lipid profiles, and insulin resistance profiles in 2655 participants for cross-sectional analysis and 332 participants for longitudinal analysis (follow-up time, 32.2 ± 7.9 months). A bivariate genetic analysis of the genetic/environmental cross-trait correlations was conducted to determine their cross-sectional relationships. After adjusting for sociodemographic factors, health behaviors, and BMI in the analysis for ALM/ht², ALM/wt and ALM/BMI had favorable associations with all cardiometabolic risk factors, while ALM/ht² had favorable associations with some risk factors. In longitudinal associations, changes in ALM/wt and ALM/BMI had inverse associations with increments of lipid profiles, insulin, and homeostasis model assessment of insulin resistance (HOMA), while change in ALM/ht² did not have associations with increments of cardiometabolic risk factors. ALM/ht² had genetic correlations with seven of nine risk factors; ALM/wt and ALM/BMI had correlations with three and one risk factors, respectively.

CONCLUSION

ALM/wt and ALM/BMI are better indicators for cardiometabolic risk factors; genetic factors may contribute more to the correlations between ALM/ht² and those traits.

Association Between Parental Socioeconomic Status and Skeletal Muscle Mass in Chinese College Students: Fitness Improvement Tactics in Youths (FITYou) Project

Purpose

The purpose of this study was to determine the association between parental socioeconomic status (SES) and skeletal muscle mass in Chinese college students.

Methods

A cross-sectional study including 2204 college freshmen was conducted in Shenyang, China. Data regarding body composition, health examinations, and a self-reported questionnaire were available from all the participants. Skeletal muscle mass assessment was completed by a bioelectrical impedance analyzer. Information on parental SES (educational levels, annual income, and occupational status) was collected via questionnaires. Covariance analysis was used to adjust for the confounding effects of sex, age, ethnicity, smoking status, alcohol use, and sleep duration.

Results

Multivariate analysis showed that college freshmen with higher parental SES levels generally had higher skeletal muscle mass after adjustment for confounding factors (mean [95% confidence interval]: low, 42.4 [42.0, 42.8]; middle, 42.9 [42.6, 43.3]; high, 43.7 [43.4, 44.1], p for trend < 0.001). Similar results were observed for paternal and maternal SES (p for trend < 0.001, respectively), whereas association between paternal SES and youth muscle mass became non-significant after adjusting for maternal SES (p for trend = 0.077). Results also showed positive linear trends for skeletal muscle mass and paternal or maternal educational levels and annual income (p for trend < 0.001, respectively), but not for occupational status.

Conclusion

This study found a positive association between parental SES and skeletal muscle mass in Chinese college students. Compared to the normalization of height or weight, body mass index-adjusted skeletal muscle mass is more likely to be associated with SES.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Estimation of skeletal muscle mass by bioimpedance and differences among skeletal muscle mass indices for assessing sarcopenia

BACKGROUND

It is crucial to assess age-related muscle mass changes and derived indices differences in geriatric medicine. We aimed to develop and validate four bioimpedance analysis (BIA) prediction equations against dual-energy X-ray absorptiometry (DEXA) and magnetic resonance image (MRI) in estimating skeletal muscle mass and to compare the differences among skeletal muscle mass indices, cutoff values, and corresponding prevalence rates of low muscle mass for assessing sarcopenia in Chinese adults.

METHODS

We measured the height (Ht), weight (Wt), appendicular lean mass (ALM) or skeletal muscle mass (ASM), total lean body mass (LBM) or skeletal muscle mass (TSM) obtained using DEXA or MRI, and a multi-frequency BIA (BCA _II;50, 250 kHz), in 371 adults aged 18.0-87.0 years. We also collected gender, age, Ht, Wt, and impedance indexes (Ht²/R₅₀, Ht²/R₂₅₀, R₅₀/Ht², R₂₅₀/Ht²) from 30,500 adults aged 18-96 years living in China. Multiple regression analyses were used to derive four prediction equations by BIA, and double cross-validation techniques and Bland-Altman analyses were used to test agreement. Various muscle mass indices and prevalence rates were depicted by line plots in regard to age trends.

RESULTS

Satisfactory results were found in the four prediction models as they had the larger R² (0.833-0.930) values and low SEE (1.409-2.335 kg) values. The predictive variables included impedance indexes (Ht²/R₅₀, R₅₀/Ht², R₂₅₀/Ht²), gender, age, Wt, and Ht. The corresponding prevalence rates of low muscle mass exhibited significant differences according to the various muscle mass indices adjusted for Ht, Wt, or body mass index (BMI), in addition to the cutoff values based on two standard deviations (2SD) of young people or the lower 20% of the study group.

CONCLUSIONS

The BIA equations have the potential to be applied as a practical method of quantifying skeletal muscle mass in Chinese adults. However, the operational methods that are most appropriate for determining the degree of low muscle mass that actually contributes to sarcopenia remains inconclusive.

Metformin ameliorates skeletal muscle atrophy in Grx1 KO mice by regulating intramuscular lipid accumulation and glucose utilization

Skeletal muscle is the largest tissue in the body, and plays a remarkable role in energy and metabolic homeostasis. Disorder in lipid metabolism and glucose utilization could impair the quality and function of skeletal muscle. Glutaredoxin-1 (Grx1) acts as a vital metabolic regulator of redox homeostasis. Recent studies have shown that Grx1 regulates hepatic lipid metabolism. The skeletal muscle also contains abundant Grx1, but the role of Grx1 in skeletal muscle remains unknown. Therefore, we investigated the effect of Grx1 on skeletal muscle. In this study, we found that Grx1-deficient mice (Grx1^-/-) spontaneously developed muscle atrophy by 3 months of age. And the p-AMPK activity and Sirt1 activity were inhibited in Grx1^-/- mice, which led to intramuscular lipid deposition and glucose utilization disorder in skeletal muscle. However, intraperitoneal injection of metformin for 15 consecutive days ameliorated skeletal muscle atrophy caused by Grx1 deficiency to a certain extent. Taken together, these findings indicate that Grx1 deficiency might induce skeletal muscle atrophy by regulating the intramuscular lipid deposition and glucose utilization, which could be attenuated by metformin. Therefore, the expression or activity of Grx1 may be a pharmacological approach to ameliorate muscle atrophy diseases, such as sarcopenia.

Beneficial Role of Replacing Dietary Saturated Fatty Acids with Polyunsaturated Fatty Acids in the Prevention of Sarcopenia: Findings from the NU-AGE Cohort

Dietary fat subtypes may play an important role in the regulation of muscle mass and function during ageing. The aim of the present study was to determine the impact of isocaloric macronutrient substitutions, including different fat subtypes, on sarcopenia risk in older men and women, while accounting for physical activity (PA) and metabolic risk. A total of 986 participants, aged 65–79 years, completed a 7-day food record and wore an accelerometer for a week. A continuous sex-specific sarcopenia risk score (SRS), including skeletal muscle mass assessed by dual-energy X-ray absorptiometry (DXA) and handgrip strength, was derived. The impact of the isocaloric replacement of saturated fatty acids (SFAs) by either mono- (MUFAs) or poly-unsaturated (PUFAs) fatty acids on SRS was determined using regression analysis based on the whole sample and stratified by adherence to a recommended protein intake (1.1 g/BW). Isocaloric reduction of SFAs for the benefit of PUFAs was associated with a lower SRS in the whole population, and in those with a protein intake below 1.1 g/BW, after accounting for age, smoking habits, metabolic disturbances, and adherence to PA guidelines. The present study highlighted the potential of promoting healthy diets with optimised fat subtype distribution in the prevention of sarcopenia in older adults.

Association of low skeletal muscle mass with the presence of advanced colorectal neoplasm: integrative analysis using three skeletal muscle mass indices

AIM

This study aimed to evaluate an association between colorectal neoplasm (CRN) and skeletal muscle mass using three widely accepted skeletal muscle mass indices (SMIs) in a large population at average risk.

METHOD

We performed a cross-sectional study using a screening colonoscopy database of 33 958 asymptomatic subjects aged 40-75 years. Appendicular skeletal muscle mass (ASM) was measured using a bioelectrical impedance analyser. ASM adjusted for height squared (ASM/ht² ), weight (ASM/wt) and body mass index (ASM/BMI) were used as indices for muscle mass. Logistic regression models were used to evaluate the association between SMIs and CRN.

RESULTS

In a multivariable-adjusted model, the risk of an advanced CRN increased linearly with decreasing quartiles for all three SMIs. The adjusted odds ratios (ORs) for advanced CRN in quartiles 1, 2 and 3 of ASM/wt compared with that in quartile 4 were 1.279, 1.196 and 1.179, respectively (P_trend  = 0.017); for ASM/BMI, ORs were 1.307, 1.144 and 1.091, respectively (P_trend  = 0.002); and for ASM/ht² , ORs were 1.342, 1.169 and 1.062, respectively (P_trend  = 0.002). The risk of distally located advanced CRN was higher in quartile 1 than in quartile 4 for all three SMIs (ASM/wt, OR = 1.356; ASM/BMI, OR = 1.383; ASM/ht² , OR = 1.430).

CONCLUSION

Our study demonstrated that low skeletal muscle mass was consistently associated with the presence of advanced CRN in a population at average risk regardless of the operational definition of the SMI, and it was particularly associated with distal advanced CRN.

Docosahexaenoic Acid, a Potential Treatment for Sarcopenia, Modulates the Ubiquitin-Proteasome and the Autophagy-Lysosome Systems

One of the characteristic features of aging is the progressive loss of muscle mass, a nosological syndrome called sarcopenia. It is also a pathologic risk factor for many clinically adverse outcomes in older adults. Therefore, delaying the loss of muscle mass, through either boosting muscle protein synthesis or slowing down muscle protein degradation using nutritional supplements could be a compelling strategy to address the needs of the world’s aging population. Here, we review the recently identified properties of docosahexaenoic acid (DHA). It was shown to delay muscle wasting by stimulating intermediate oxidative stress and inhibiting proteasomal degradation of muscle proteins. Both the ubiquitin–proteasome and the autophagy–lysosome systems are modulated by DHA. Collectively, growing evidence indicates that DHA is a potent pharmacological agent that could improve muscle homeostasis. Better understanding of cellular proteolytic systems associated with sarcopenia will allow us to identify novel therapeutic interventions, such as omega-3 polyunsaturated fatty acids, to treat this disease.

Effect of Dairy Protein Intake on Muscle Mass among Korean Adults: A Prospective Cohort Study

This cohort study aimed to identify the associations of dairy protein intake with the risk of developing a low muscle mass during a 12-year follow-up period, using data from 4412 middle-aged Korean Genome and Epidemiology Study participants with a normal baseline muscle mass. Dairy protein intake at baseline was assessed using a semi-quantitative Food Frequency Questionnaire. Skeletal muscle mass index (SMI), defined as the weight-adjusted skeletal muscle mass, was measured biennially using multi-frequency bioelectrical impedance analyses. Cox proportional hazards regression analysis was used to calculate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Overall, 395 subjects developed a low SMI (%) during an average follow-up of 141 (19-152) months. The average consumption of milk and other dairy products was 73.6 and 104.1 g/day, respectively. In men, a higher dairy protein intake was associated with a decreased risk of developing a low SMI (tertile 3 [T3] vs. T1, HR: 0.63; 95% CI: 0.42, 0.94; p for trend = 0.029). In a stratified analysis according to a total protein intake, this association was stronger in the lower-protein intake group (HR: 0.59; 95% CI: 0.35, 0.99; p for trend = 0.036) but not detected in the higher-protein intake group. Men who consumed milk ≥1 time/day had a significantly lower risk of developing a low SMI (HR: 0.62; 95% CI: 0.39, 0.98; p for trend = 0.023). No significant associations were observed in women. In summary, dairy consumption appears to be beneficial for decreasing the risk of developing a low muscle mass in middle-aged Korean men.

Body composition with dual energy X-ray absorptiometry: from basics to new tools

Dual-energy X-ray absorptiometry (DXA) in nowadays considered one of the most versatile imaging techniques for the evaluation of metabolic bone disorders such as osteoporosis, sarcopenia and obesity. The advantages of DXA over other imaging techniques are the very low radiation dose, its accuracy and simplicity of use. In addition, fat mass (FM) and lean mass (LM) values by DXA shows very good accuracy compared to that of computed tomography and magnetic resonance imaging. In this review we will explain the technical working principles of body composition with DXA, together with the possible limitations and pitfalls that should be avoided in daily routine to produce high-quality DXA examinations. We will also cover the current clinical practical application of whole body DXA values, with particular emphasis on the use of LM indices in the diagnostic workup of reduced muscle mass, sarcopenia and osteosarcopenic obesity according to the most recent guidelines. The possible use of adipose indices will be considered, such as the fat mass index (FMI) or the android/gynoid ratio, as well as lipodystrophy indices and the evaluation of visceral adipose tissue (VAT). Whenever available, we will provide possible cut-off diagnostic values for each of these LM and FM indices, according to current literature and guidelines.

Exercise Programs for Muscle Mass, Muscle Strength and Physical Performance in Older Adults with Sarcopenia: A Systematic Review and Meta-Analysis

Sarcopenia is an age-related condition that is characterized by progressive and generalized loss of muscle mass and function. Exercise treatment has been the most commonly used intervention among elderly populations. We performed a systematic review and meta-analysis to evaluate the available literature related to the effects of exercise interventions/programs on muscle mass, muscle strength and physical performance in older adults with sarcopenia. We searched PubMed, EMBASE, MEDLINE and the Web of Science for randomized controlled trials and controlled clinical trials exploring exercise in older adults with sarcopenia published through July 2019 without any language restrictions. Pooled analyses were conducted using Review Manager 5.3, with standardized mean differences (SMDs) and fixed-effect models. A total of 3898 titles and abstracts were initially identified, and 22 studies (1041 individuals, 80.75% females, mean age ranged from 60.51 to 85.90 years) were included in the meta-analysis. The exercise programs in the studies consisted of 30 to 80 min of training, with 1 to 5 training sessions weekly for 6 to 36 weeks. Muscle strength (grip strength [SMD 0.57, 95 % CI 0.42 to 0.73, P <0.00001] and timed five chair stands [SMD -0.56, 95 % CI -0.85 to -0.28, P < 0.0001]) and physical performance (gait speed [SMD 0.44, 95 % CI 0.26 to 0.61, P < 0.00001] and the timed up and go test [SMD -0.97, 95 % CI -1.22 to -0.72, P < 0.00001]) showed significant improvement following exercise treatment, while no differences in muscle mass (ASM [SMD 0.15, 95 % CI -0.05 to 0.36, P = 0.15] and ASM/height² [SMD 0.21, 95 % CI -0.05 to 0.48, P = 0.12]) were detected. Exercise programs showed overall significant positive effects on muscle strength and physical performance but not on muscle mass in sarcopenic older adults.

Role of Skeletal Muscle in Insulin Resistance and Glucose Uptake

The skeletal muscle is the largest organ in the body, by mass. It is also the regulator of glucose homeostasis, responsible for 80% of postprandial glucose uptake from the circulation. Skeletal muscle is essential for metabolism, both for its role in glucose uptake and its importance in exercise and metabolic disease. In this article, we give an overview of the importance of skeletal muscle in metabolism, describing its role in glucose uptake and the diseases that are associated with skeletal muscle metabolic dysregulation. We focus on the role of skeletal muscle in peripheral insulin resistance and the potential for skeletal muscle-targeted therapeutics to combat insulin resistance and diabetes, as well as other metabolic diseases like aging and obesity. In particular, we outline the possibilities and pitfalls of the quest for exercise mimetics, which are intended to target the molecular mechanisms underlying the beneficial effects of exercise on metabolic disease. We also provide a description of the molecular mechanisms that regulate skeletal muscle glucose uptake, including a focus on the SNARE proteins, which are essential regulators of glucose transport into the skeletal muscle. © 2020 American Physiological Society. Compr Physiol 10:785-809, 2020.

Prognostic significance of low pectoralis muscle mass on preoperative chest computed tomography in localized non-small cell lung cancer after curative-intent surgery

OBJECTIVES

The impact of sarcopenia on the outcome in patients following resection of non-small cell lung cancer is yet to be fully determined. This study aimed to evaluate the clinical utility of a computed tomography-based pectoralis muscle assessment, which reflects sarcopenia, to predict the risk of postoperative outcomes.

MATERIALS AND METHODS

This retrospective study included 347 consecutive patients undergoing curative-intent resection of non-small cell lung cancer from 2009 to 2013. The pectoralis muscle index (pectoralis muscle area/body mass index) was assessed at the level of the fourth thoracic vertebra on chest axial images. The primary outcomes were compared between the lowest gender-specific quintile (sarcopenia) and the other quintiles according to the index. The prognostic significance of low pectoralis muscle index was calculated by the Cox proportional hazards regression model. A propensity score matching analysis was performed to adjust the differences in clinical characteristics.

RESULTS

Sixty-nine patients were identified with sarcopenia according to the lowest gender-specific quintile of pectoralis muscle index. Patients with sarcopenia exhibited worse 5-year overall survival rate compared with patients without sarcopenia (64.2 % vs. 86.7 %, P < 0.001). Even in stage I non-small cell lung cancer, the rate of 5-year overall survival in the sarcopenia group was lower than that in the non-sarcopenia group (74.2 % vs. 92.4 %, P = 0.001). Multivariate analysis revealed that low pectoralis muscle index was independently associated with adverse overall survival (hazard ratio: 2.09, 95 % confidence interval: 1.20-3.62, P = 0.009). After propensity score matching, the prognostic impact of sarcopenia based on low pectoralis muscle index was also robust for overall survival (hazard ratio: 3.23, 95 % confidence interval: 1.38-7.60, P = 0.007).

CONCLUSIONS

Low pectoralis muscle index was significantly associated with poor long-term outcomes in patients with localized non-small cell lung cancer after curative surgery. This may help assist preoperative risk stratification and longitudinal management after surgery.

Functional and Clinical Characteristics for Predicting Sarcopenia in Institutionalised Older Adults: Identifying Tools for Clinical Screening

BACKGROUND

Recently, the European Working Group on Sarcopenia in Older People (EWGSOP2) has updated the sarcopenia definition based on objective evaluation of muscle strength, mass and physical performance. The aim of this study was to analyse the relationship between sarcopenia and clinical aspects such as functionality, comorbidity, polypharmacy, hospitalisations and falls in order to support sarcopenia screening in institutionalised older adults, as well as to estimate the prevalence of sarcopenia in this population using the EWGSOP2 new algorithm.

METHODS

A multicentre cross-sectional study was conducted on institutionalised older adults (n = 132, 77.7% female, mean age 82 years). Application of the EWGSOP2 algorithm consisted of the SARC-F questionnaire, handgrip strength (HG), appendicular skeletal muscle mass index (ASMI) and Short Physical Performance Battery (SPPB). Clinical study variables were: Barthel Index (BI), Abbreviated Charlson's Comorbidity Index (ACCI), number of medications, hospital stays and falls.

RESULTS

Age, BI and ACCI were shown to be predictors of the EWGSOP2 sarcopenia definition (Nagelkerke's R-square = 0.34), highlighting the ACCI. Sarcopenia was more prevalent in older adults aged over 85 (p = 0.005), but no differences were found according to gender (p = 0.512).

CONCLUSION

BI and the ACCI can be considered predictors that guide healthcare professionals in early sarcopenia identification and therapeutic approach.

Amount of Protein Required to Improve Muscle Mass in Older Adults

Increased protein intake has been suggested as an effective strategy to treat age-related loss of muscle mass and function, but the amount of protein required to improve muscle and function without exercise in older adults remains unclear. Thus, this secondary data analysis aimed to assess what amount of protein from habitual protein intake was positively associated with changes in muscle mass and gait speed in older women and men. Ninety-six community-dwelling older adults consumed 0.8, 1.2, or 1.5 g/kg/day of protein and maintained their usual physical activity for 12 weeks. Increased protein intake of >0.54 g/kg/day was positively associated with changes in appendicular skeletal muscle mass (ASM)/weight (B = 0.591, p = 0.026), ASM/body mass index (B = 0.615, p = 0.023), and ASM:fat ratio (B = 0.509, p = 0.030) in older men. However, change in protein intake was not associated with change in muscle mass in older women. Additionally, change in protein intake was not associated with change in gait speed in older women and men. The present study suggested that an increased absolute protein amount of >0.54 g/kg/day from habitual protein intake was positively associated with change in muscle mass in older men.

Association between the Thigh Muscle and Insulin Resistance According to Body Mass Index in Middle-Aged Korean Adults

BACKGROUND

We examined the associations between thigh muscle area (TMA) and insulin resistance (IR) according to body mass index (BMI) in middle-aged Korean general population.

METHODS

TMA was measured using quantitative computed tomography and corrected by body weight (TMA/Wt) in 1,263 men, 788 premenopausal women, and 1,476 postmenopausal women all aged 30 to 64 years. The tertiles of TMA/Wt were calculated separately for men and for premenopausal and postmenopausal women. Homeostatic model assessment for insulin resistance (HOMA-IR) was performed using fasting blood glucose and insulin levels, and increased IR was defined according to sex-specific, top quartiles of HOMA-IR. Associations between the TMA/Wt tertiles and increased IR according to the BMI categories (<25 and ≥25 kg/m²) were assessed using multivariable logistic regression analysis.

RESULTS

In men with higher BMIs, but not in those with lower BMIs, the presence of an increased IR had significantly higher odds ratios in the lower TMA/Wt tertiles, even after adjustment for visceral fat area. However, in premenopausal and postmenopausal women, there was no significant inverse association between TMA/Wt tertiles and increased IR, regardless of BMI category.

CONCLUSION

Our findings suggest that the thigh muscle is inversely associated with IR in men, particularly in those with higher BMIs.

Muscle mass reduction, low muscle strength, and their combination are associated with arterial stiffness in community-dwelling elderly population: the Wakayama Study

Age-related loss of skeletal muscle mass and function is associated with some predisposing factors that increase the risk of vascular damage. This study aimed to examine whether muscle mass reduction, low muscle strength, and their combination were related to arterial stiffness in community-dwelling elderly population. Study participants consisted of 1046 elderly individuals (aged 72 ± 5 years) without cardiovascular disease, chronic kidney disease, or liver disease. Bioelectrical impedance analysis was performed to estimate appendicular skeletal muscle mass (ASM). A value for ASM was normalized for height (ASM index, kg/m²). Handgrip strength (HGS) was measured using a Smedley grip dynamometer. Brachial-ankle pulse wave velocity (baPWV) was evaluated as an index of arterial stiffness using a simple automatic oscillometric technique. When participants were stratified based on baPWV cut-off values (< 1800 cm/s, 1800 to 1999 cm/s, ≥ 2000 cm/s), ASM index and HGS progressively decreased with an increase in baPWV levels (P for trend < 0.001). In multiple regression analysis, baPWV was significantly associated with ASM index (β = -0.270, P < 0.001) and HGS (β = -0.102, P < 0.001) independent of potential confounding factors. The baPWV of the subgroup with low ASM index and low HGS was significantly higher than that of those with only low ASM index or low HGS (P < 0.001). These results suggest that loss of skeletal muscle mass and function is associated with increased arterial stiffness in the elderly population, and the combination of muscle mass reduction and low muscle strength may lead to greater arterial stiffness than each of the individual conditions.

Is postural dysfunction related to sarcopenia? A population-based study

Postural dysfunction is one of the most common community health symptoms and frequent chief complaints in hospitals. Sarcopenia is a syndrome characterized by degenerative loss of skeletal muscle mass, muscle quality, and muscle strength, and is the main contributor to musculoskeletal impairment in the elderly. Previous studies reported that loss of muscle mass is associated with a loss of diverse functional abilities. Meanwhile, there have been limited studies concerning postural dysfunction among older adults with sarcopenia. Although sarcopenia is primarily a disease of the elderly, its development may be associated with conditions that are not exclusively seen in older persons. Also, recent studies recognize that sarcopenia may begin to develop earlier in life. The objective of this paper was to investigate the association between the prevalence of sarcopenia and postural dysfunction in a wide age range of adults using data from a nationally representative cohort study in Korea. Korean National Health & Nutrition Exhibition Survey V (KNHANES V, 2010–2012) data from the fifth cross-sectional survey of the South Korean population performed by the Korean Ministry of Health and Welfare were used. Appendicular skeletal muscle mass (ASM)/height (ht)² was used to define sarcopenia, and the Modified Romberg test using a foam pad (“foam balance test”) was performed to evaluate postural dysfunction. ASM/ht² was lower in women and significantly decreased with age in men. Subjects with sarcopenia were significantly more likely to fail the foam balance test, regardless of sex and age. Regression analysis showed a significant relationship between sarcopenia and postural dysfunction (OR: 2.544, 95% CI: 1.683–3.846, p<0.001). Multivariate regression analysis revealed that sarcopenia (OR: 1.747, 95% CI: 1.120–2.720, p = 0.014) and age (OR: 1.131, 95% CI: 1.105–1.158, p<0.001) are independent risk factors for postural instability. In middle age subjects, the adjusted OR for sarcopenia was 3.344 (95% CI: 1.350–8.285) (p = 0.009). The prevalence of postural dysfunction is higher in sarcopenia patients, independent of sex and age.

Association of Dietary Variety Status and Sarcopenia in Korean Elderly

BACKGROUND

Sarcopenia is associated with a variety of factors including age, diseases, exercise, and heredity. In particular, diet is known to affect changes in muscle mass loss.

METHODS

The purpose of this study was to analyze the diversity of food intake according to the presence of sarcopenia in elderly people over 65 years old using the 2008 to 2011 Korea National Health and Nutrition Examination Survey. The differences in subjects' general characteristics, lifestyle, and intake of 15 food groups were compared, and the risk odds ratio (OR) for sarcopenia was calculated for each food intake by gender.

RESULTS

The proportion of sarcopenia was 27.7% for males and 24.3% for females. The sarcopenia group had significantly lower intakes of nuts and seeds, meats, and milks than the non-sarcopenia group in males. The females had significantly lower intake of fruits, milks, and beverages in non-sarcopenia group. The dietary diversity score was significantly lower in females with sarcopenia than non-sarcopenia group. Regression analysis of the risk OR for sarcopenia according to food group intake showed that the subjects in the lowest tertile (<31.1 g) had a 1.83 times (95% confidence interval [CI], 1.13-2.42) risk for sarcopenia in males. In case of milks intake of females, the risk for sarcopenia increased 1.39 times (95% CI, 1.11-1.86) in subjects with the lowest tertile (<30.1 g).

CONCLUSIONS

Dietary diversity status was the most vulnerable to female with sarcopenia. Sarcopenia was associated with meat intake in male and milk intake in female.

Novel Insights into the Pathogenesis of Spinal Sarcopenia and Related Therapeutic Approaches: A Narrative Review

Spinal sarcopenia is a complex and multifactorial disorder associated with a loss of strength, increased frailty, and increased risks of fractures and falls. In addition, spinal sarcopenia has been associated with lumbar spine disorders and osteoporosis, which renders making decisions on treatment modalities difficult. Patients with spinal sarcopenia typically exhibit lower cumulative survival, a higher risk of in-hospital complications, prolonged hospital stays, higher postoperative costs, and higher rates of blood transfusion after thoracolumbar spine surgery. Several studies have focused on the relationships between spinal sarcopenia, appendicular muscle mass, and bone-related problems-such as osteoporotic fractures and low bone mineral density-and malnutrition and vitamin D deficiency. Although several techniques are available for measuring sarcopenia, each of them has its advantages and shortcomings. For treating spinal sarcopenia, nutrition, physical therapy, and medication have been proven to be effective; regenerative therapeutic options seem to be promising owing to their repair and regeneration potential. Therefore, in this narrative review, we summarize the characteristics, detection methodologies, and treatment options for spinal sarcopenia, as well as its role in spinal disorders.

Cut-off points of appendicular lean soft tissue for identifying sarcopenia in older adults in Brazil: a cross-sectional study

Introduction

Introduction: appropriate appendicular lean soft tissue (ALST) parameters to identify sarcopenia in Brazil are scarce. The use of international references may lead to a false positive diagnosis. The objective was to propose cut-off points to identify sarcopenia in older men and women using DXA-derived ALST values from a young adult population. Methods: this was an observational study with a cross-sectional analysis. University students of both sexes (n = 125), aged 20 to 30 years, underwent anthropometric measurements and DXA scanning to obtain their ALST (kg). Cut-off points for sarcopenia were set at -2 standard deviations (-2SDs) away from the mean ALST of a young sample. Absolute values and indices (ALST/height2, ALST/weight, and ALST/body mass index [BMI]) were considered as recommended by international consensus. Results: compared to women, men presented higher values of weight, height, BMI, bone mineral content, lean soft tissue, ALST, and ALST index (kg/m²). Only fat mass was higher in women, and age was not different between genders. The -2SD ALST indices obtained were ≤ 6.56 kg/m² for men and ≤ 4.67 kg/m² for women. They were below international and national values, which tended to classify false positives. Conclusions: the -2SD ALST values proposed here are validated cut-offs for identifying low muscle in older adults and to prevent misdiagnosis with sarcopenia. In addition, they contribute to efficient monitoring and control of this disease in geriatric populations.

Dietary Fibre May Mitigate Sarcopenia Risk: Findings from the NU-AGE Cohort of Older European Adults

Sarcopenia is characterised by a progressive loss of skeletal muscle mass and physical function as well as related metabolic disturbances. While fibre-rich diets can influence metabolic health outcomes, the impact on skeletal muscle mass and function is yet to be determined, and the moderating effects by physical activity (PA) need to be considered. The aim of the present study was to examine links between fibre intake, skeletal muscle mass and physical function in a cohort of older adults from the NU-AGE study. In 981 older adults (71 ± 4 years, 58% female), physical function was assessed using the short-physical performance battery test and handgrip strength. Skeletal muscle mass index (SMI) was derived using dual-energy X-ray absorptiometry (DXA). Dietary fibre intake (FI) was assessed by 7-day food record and PA was objectively determined by accelerometery. General linear models accounting for covariates including PA level, protein intake and metabolic syndrome (MetS) were used. Women above the median FI had significantly higher SMI compared to those below, which remained in fully adjusted models (24.7 ± 0.2% vs. 24.2 ± 0.1%, p = 0.011, η²p = 0.012). In men, the same association was only evident in those without MetS (above median FI: 32.4 ± 0.3% vs. below median FI: 31.3 ± 0.3%, p = 0.005, η²p = 0.035). There was no significant impact of FI on physical function outcomes. The findings from this study suggest a beneficial impact of FI on skeletal muscle mass in older adults. Importantly, this impact is independent of adherence to guidelines for protein intake and PA, which further strengthens the potential role of dietary fibre in preventing sarcopenia. Further experimental work is warranted in order to elucidate the mechanisms underpinning the action of dietary fibre on the regulation of muscle mass.

Aging Fits the Disease Criteria of the International Classification of Diseases

The disease criteria used by the World Health Organization (WHO) were applied to human biological aging in order to assess whether aging can be classified as a disease. These criteria were developed for the 11th revision of the International Classification of Diseases (ICD) and included disease diagnostics, mechanisms, course and outcomes, known interventions, and linkage to genetic and environmental factors. RESULTS: Biological aging can be diagnosed with frailty indices, functional, blood-based biomarkers. A number of major causal mechanisms of human aging involved in various organs have been described, such as inflammation, replicative cellular senescence, immune senescence, proteostasis failures, mitochondrial dysfunctions, fibrotic propensity, hormonal aging, body composition changes, etc. We identified a number of clinically proven interventions, as well as genetic and environmental factors of aging. Therefore, aging fits the ICD-11 criteria and can be considered a disease. Our proposal was submitted to the ICD-11 Joint Task force, and this led to the inclusion of the extension code for "Ageing-related" (XT9T) into the "Causality" section of the ICD-11. This might lead to greater focus on biological aging in global health policy and might provide for more opportunities for the new therapy developers.

Impact of body fat distribution and sarcopenia on the overall survival in patients with spinal metastases receiving radiotherapy treatment: a prospective cohort study

Introduction: An increasing number of patients is diagnosed with spinal metastases due to elevated cancer incidence and improved overall survival. Patients with symptomatic spinal bone metastases often receive radiotherapy with or without surgical stabilisation. Patients with a life expectancy of less than 3 months are generally deemed unfit for surgery, therefore adequate pre-treatment assessment of life expectancy is necessary. The aim of this study was to assess new factors associated with overall survival for this category of patients.Patients and methods: Patients who received radiotherapy for thoracic or lumbar spinal metastases from June 2013 to December 2016 were included in this study. The pre-treatment planning CT for radiotherapy treatment was used to assess the patient's visceral fat area, subcutaneous fat area, total muscle area and skeletal muscle density on a single transverse slice at the L3 level. The total muscle area was used to assess sarcopenia. Furthermore, data were collected on age, sex, primary tumour, Karnofsky performance score, medical history, number of bone metastases, non-bone metastases and neurological symptoms. Univariable and multivariable cox regressions were performed to determine the association between our variables of interest and the survival at 90 and 365 days.Results: A total of 310 patients was included. The median age was 67 years. Overall survival rates for 90 and 365 days were 71% and 36% respectively. For 90- and 365-day survival, the Karnofsky performance score, muscle density and primary tumour were independently significantly associated. The visceral or subcutaneous fat area and their ratio and sarcopenia were not independently associated with overall survival.Conclusions: Of the body morphology, only muscle density was statistically significant associated with overall survival after 90 and 365 days in patients with spinal bone metastases. Body fat distribution was not significantly associated with overall survival.

Prevalence and association of single nucleotide polymorphisms with sarcopenia in older women depends on definition

The prevalence of sarcopenia depends on the definition used. There are, however, consistent sarcopenic characteristics, including a low muscle mass and muscle strength. Few studies have investigated the relationship between sarcopenia and genotype. A cross-sectional study was conducted with 307 community-dwelling ≥60-year-old women in South Cheshire, UK. Handgrip strength was assessed with a handgrip dynamometer and skeletal muscle mass was estimated using bioelectrical impedance. DNA was extracted from saliva (∼38%) or blood (∼62%) and 24 single-nucleotide polymorphisms (SNPs) were genotyped. Three established sarcopenia definitions - %Skeletal Muscle Mass (%SMM), Skeletal Muscle Mass Index (SMI) and European Working Group on Sarcopenia in Older People (EWGSOP) - were used to assess sarcopenia prevalence. Binary logistic regression with age as covariate was used to identify SNPs associated with sarcopenia. The prevalence of sarcopenia was: %SMM 14.7%, SMI 60.6% and EWGSOP 1.3%. Four SNPs were associated with the %SMM and SMI definitions of sarcopenia; FTO rs9939609, ESR1 rs4870044, NOS3 rs1799983 and TRHR rs7832552. The first three were associated with the %SMM definition, and TRHR rs7832552 with the SMI definition, but none were common to both sarcopenia definitions. The gene variants associated with sarcopenia may help proper counselling and interventions to prevent individuals from developing sarcopenia.

Relation Between Low Pulmonary Function and Skeletal Muscle Index in Burn Patients with Major Burn Injury and Smoke Inhalation: A Retrospective Study

This report is to evaluate the relation between pulmonary function, respiratory muscle strength, and skeletal muscle index (SMI) in patients with major burn injury and smoke inhalation. A total of 54 inhalation burn patients were analyzed. Appendicular skeletal muscle mass (ASM) is a sum of the muscle mass of both arms and legs. SMI is adjusting for body size using body mass index (ASM/BMI). Spirometry was performed to evaluate pulmonary function. Pulmonary function tests included peak cough flow (PCF), forced vital capacity (FVC), 1-s forced expiratory volume (FEV1), forced expiratory flow rate between 25 and 75% of the FVC (FEF 25–75), FEV1/FVC ratio expressed as a percentage (FEV1/FVC %), peak expiratory flow (PEF), and maximum voluntary ventilation. Expiratory and inspiratory muscle strengths were measured. The relations between pulmonary function, respiratory muscle strength, and SMI were investigated. SMI showed significant correlations with PCF (r = 0.34 and P = 0.02), FVC (r = 0.55 and P &lt; 0.001), FEV1 (r = 0.45 and P = 0.001), and PEF (r = 0.35 and P = 0.01). In multiple regression analysis including age, TBSA, duration of mechanical ventilation, and postburn days studied, SMI was significantly related to FVC, PCF, FEV1, FEV1/FVC, and PEF (P &lt; 0.001, P = 0.02, P = 0.001, P = 0.04, and P = 0.03). Pulmonary function tests are significantly related to SMI in patients with major burn injury and smoke inhalation. Intensive treatment on muscle wasting in patients with burn injury has been proven to be important for improving pulmonary functions.

Exercise and Organ Cross Talk

Chronic heart failure, diabetes, depression, and other chronic diseases are associated with high mortality rate and low cure rate. Exercise induces muscle contraction and secretes multiple myokines, which affects the signaling pathways in skeletal muscle tissues and regulate remote organ functions. Exercise is known to be effective in treating a variety of chronic diseases. Here we summarize how exercise influences skeletal muscle, heart, brain, gut, and liver, and prevents heart failure, cognitive dysfunction, obesity, fatty liver, and other diseases. Exercise training may achieve additional benefits as compared to the present medication for these chronic diseases through cross talk among skeletal muscle and other organs.

Effect of obesity and underweight status on the hospital-acquired functional decline in patients with cardiovascular surgery: an analysis of data from a prospective observational multicenter cohort study

OBJECTS

The aim of this study was to determine the association between underweight or obese status and hospital- acquired functional decline (HAFD) following cardiovascular surgery.

METHODS

We performed a retrospective, observational, multicenter cohort study of cardiovascular surgery patients between April, 2010, and June, 2017. Body mass index (BMI) was categorized into four classes: underweight group (< 18.5 kg/m²), normal weight group (18.5 to < 25 kg/m²), overweight group (25 to < 30 kg/m²), and obese group (≥ 30 kg/m²). HAFD was defined as a decrease of at least one point on the short physical performance battery score at discharge, compared with the preoperative score.

RESULTS

A total of 3,850 adult patients were included in the analysis data set (median age 72 years, 35% female). A total of 811 (21.0%) patients demonstrated HAFD: 27.2% in the underweight group, 21.3% in the normal weight group, 18.8% in the overweight group, and 19.3% in the obese group. The relative risk for HAFD was 1.381 (95% CI 1.052-1.814) for the underweight group versus the normal weight group, although that is comparable to the obese group after adjustment by confounding factors. Analyses of subgroup interactions showed that the relative risk of HAFD in the obese group compared with the normal group was higher in patients with muscle wasting (p < 0.05).

CONCLUSION

HAFD was significantly worse for underweight patients following cardiovascular surgery. In contrast, obese status was not associated with HAFD, exclusive of the obese patients with muscle wasting.

Prognostic role of the advanced lung cancer inflammation index in cancer patients: a meta-analysis

Background

Inflammation plays a critical role in the development and progression of cancers. The advanced lung cancer inflammation index (ALI) is thought to be able to reflect systemic inflammation better than current biomarkers. However, the prognostic significance of the ALI in various types of cancer remains unclear. Our meta-analysis aimed to comprehensively investigate the relationship between the ALI and oncologic outcomes to help physicians better assess the prognosis of cancer patients.

Methods

The PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang databases were searched for relevant studies. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated and pooled from the included studies. Furthermore, a sensitivity analysis was performed to evaluate the reliability of the articles. Finally, Begg’s test, Egger’s test, and the funnel plot were applied to assess the significance of publication bias.

Results

In total, 1736 patients from nine studies were included in our meta-analysis. The median cutoff value for the ALI was 23.2 (range, 15.5–37.66) in the analyzed studies. The meta-analysis showed that there was a statistically significant relationship between a low ALI and worse overall survival (OS) in various types of cancer (HR = 1.70, 95% CI = 1.41–1.99, P < 0.001). Moreover, results from subgroup meta-analysis showed that the ALI had a significant prognostic value in non-small cell lung cancer, small cell lung cancer, colorectal cancer, head and neck squamous cell carcinoma, and diffuse large B cell lymphoma (P < 0.05 for all).

Conclusions

These results showed that a low ALI was associated with poor OS in various types of cancer, and the ALI could act as an effective prognostic biomarker in cancer patients.

Muscle Evaluation in Axial Spondyloarthritis-The Evidence for Sarcopenia

Sarcopenia is a syndrome defined as a progressive and generalized skeletal muscle disorder associated with an increased likelihood of adverse outcomes such as falls, fractures, physical disability, and death. The actual definition of sarcopenia is based on a reduction in the values of three parameters: strength, muscle mass quantity or quality, and physical performance (the determinant of severity). Muscle wasting is a common feature in several chronic diseases, such as spondyloarthritis (SpA), and significantly increases patient morbidity and mortality. Although there has been huge progress in this field over recent years, the absence of a clear definition and clear diagnostic criteria of sarcopenia has resulted in inconsistent information regarding muscle-involvement in SpA. Thus, the aim of this review is to collect relevant evidence on muscular changes occurring during the disease process from the published literature, according to the recommended tools for sarcopenia evaluation proposed by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2). In addition, data from histological, electromyography, and biochemical muscle analyses of SpA patients are also reviewed. Overall, a reduction in muscle strength with a systemic decrease in lean mass seems to be associated with a gait speed compromise. This information is usually fragmented, with no studies considering the three parameters together. This paper represents a call-to-action for the design of new studies in the future.

Recent Issues on Body Composition Imaging for Sarcopenia Evaluation

Recently, sarcopenia has garnered renewed interest. Sarcopenia is a disease characterized by decreased skeletal muscle mass and strength/function, which can impair the quality of life and increase physical disability, adverse metabolic effects, and mortality. Imaging tools for evaluating and diagnosing sarcopenia have developed rapidly. Radiologists should be aware of sarcopenia and its clinical implications. We review current knowledge about sarcopenia, its pathophysiological impact, and advantages and disadvantages of methods for evaluation of sarcopenia focusing on body composition imaging modalities such as whole-body dual-energy X-ray absorptiometry, CT, and MRI. Controversial issues are discussed, including the lack of consensus and standardization of the disease definition, imaging modality, measurement methods, and diagnostic cutoff points.

Association between Colorectal Adenoma and Hand Grip Strength in the Elderly

Background

Obesity is known as an important risk factor for colorectal adenoma. However, for the elderly with changes in body composition, reduced muscle, and increased fat, the body mass index (BMI), one of the most commonly used indicators of obesity, is limited in predicting a link to colorectal cancer. This study aimed to investigate the relationship between colorectal adenoma and grip strength that can predict muscle reduction in the elderly.

Methods

This study included 262 participants aged ≥65 years who underwent medical examination between June 2015 and August 2018. The control group comprised participants with normal findings or hyperplasia and other benign lesions, except adenoma on colonoscopy, whereas the adenoma group consisted of participants with more than one adenoma. Grip strength was alternately measured twice for each hand using a hydraulic dynamometer.

Results

The grip strength was statistically lower in the adenoma group than in the control group among women (P=0.042). For both sexes, grip strength was significantly lower in participants with ≥5 adenomas than in those with <5 adenomas (P=0.021, P=0.007). Similarly, men with large adenomas (≥7 mm) exhibited significantly lower grip strength than did those with small adenomas (<7 mm) (P=0.004). Even after correction for age, BMI, smoking status, alcohol consumption, exercise, insulin resistance, hypertension, and diabetes, the negative correlation between grip strength and number of adenomas among men and women remained (P=0.034, P=0.019).

Conclusions

A significant relationship between hand grip strength and number of colorectal adenomas was noted.

Comparison between grip strength and grip strength divided by body weight in their relationship with metabolic syndrome and quality of life in the elderly

Strength measures should be normalized by body mass; however, the definition of sarcopenia includes only simple grip strength. Thus, we compared the relationship of grip strength and grip strength divided by body weight or body mass index to two major consequences of sarcopenia, namely metabolic syndrome and poor quality of life. Data from the participants (aged 60 years or older) of the Sixth Korea National Health and Nutrition Examination were analyzed. Metabolic syndrome was defined according to the Adult Treatment Panel III guidelines with some modifications appropriate for Koreans. Quality of life was assessed using the EuroQoL Five-dimension questionnaire. Multiple logistic regression models were used to evaluate the association of grip strength and grip strength divided by body weight with metabolic syndrome and quality of life. A total of 1273 men and 1436 women were included in the analyses. Grip strength was not related to metabolic syndrome, whereas grip strength divided by body weight and grip strength normalized by body mass index revealed a dense dose-response relationship. All measures showed a similar correlation with quality of life. Grip strength divided by body weight can be superior to simple grip strength and grip strength normalized by body mass index in representing the metabolic aspects of sarcopenia.

Geographical differences in osteoporosis, obesity, and sarcopenia related traits in white American cohorts

It has been reported that geographical variation influences bone mineral density (BMD), obesity, and sarcopenia related traits in other countries. However, there is lack of similar studies in the US population. In this study, we compared data from three US study cohorts to evaluate geographical variations of BMD and body composition. BMD, fat mass and lean mass were collected from Dual-energy X-ray absorptiometry machine. ANCOVA and Chi-square tests were used to compare the differences between BMDs, obesity and sarcopenia related traits from different regional sites (Omaha, Kansas City and Baton Rouge/New Orleans). Eta-squared was used to measure the effect sizes of these differences. A total of 11,315 Caucasians from our previous three study cohorts were compared. There was no significant geographical difference in BMD for males or females under the criteria of p-values < 0.05 and effect size η² > 0.01. There were significant geographical differences with medium effect size (p-value < 0.001, 0.01 < η² < 0.14) for whole body fat mass percentage and index of low muscle mass. For Caucasians in the United States, there is no significant geographical effect found on BMD. The obesity and sarcopenia related traits are significantly different between the three study cohorts.

Effects of sarcopenia, body mass indices, and sarcopenic obesity on diastolic function and exercise capacity in Koreans

AIMS

Obesity induces left ventricular diastolic dysfunction and ultimately causes heart failure. Sarcopenic obesity is common in heart failure with preserved ejection fraction (HFpEF). However, the precise mechanism by which sarcopenic obesity is related to HFpEF is poorly understood. We aimed to evaluate the combined effect of sarcopenia (SP) and obesity on left ventricular diastolic function and exercise capacity.

METHODS

This study included 733 healthy subjects who underwent health check-ups in a tertiary hospital in Korea. All participants were categorized into four groups: non-SP/non-obese, SP/non-obese, non-SP/obese, and SP/obese. Comprehensive echocardiography with cardiopulmonary exercise testing was performed. Diastolic dysfunction was defined as an E/e' ratio ≥ 10.

RESULTS

Across SP and obesity groups, a gradual decrease in e' velocity and an increase in the E/e' ratio was noted after adjustment for age and sex. Furthermore, a gradual decrease in percent-predicted peak VO₂ was observed across the groups. In the multivariate logistic regression analysis, the SP/obese group had the highest risk for diastolic dysfunction (OR 4.27, 95% CI 2.41-7.57), followed by the non-SP/obese group (OR 2.88, 95% CI 1.57-5.29) and the SP/non-obese group (OR 1.90, 95% CI 1.01-3.56) compared with the reference (non-SP/non-obese) group even after controlling for various confounders.

CONCLUSION

Sarcopenic obesity was associated with impaired diastolic function and decreased exercise capacity, suggesting a possible mechanism by which sarcopenic obesity contributes to the development of HFpEF.

Sarcopenia Associated with Chronic Obstructive Pulmonary Disease

Sarcopenia is frequently associated with chronic diseases such as chronic obstructive pulmonary disease (COPD) and cancer. COPD, which is characterized by an irreversible airflow limitation, exacerbates respiratory distress as the disease progresses. The prevalence of sarcopenia in stable COPD was reported to be 15% to 25% in previous foreign studies and 25% in a Korean study. As the amount of activity decreases, muscle mass decreases and eventually oxygen cannot be used effectively, resulting in a vicious cycle of deterioration of exercise capacity. Deconditioning due to decreased activity is a major cause of limb muscle dysfunction in patients with COPD. In these patients, the factors that decrease muscle strength and endurance include chronic inflammation, oxidative stress, inactivity, hypoxemia, hormone abnormality, deficits of nutrients such as protein and vitamin D, and the use of systemic corticosteroid. Therefore, treatment and management should either inhibit this process or should be directed toward supplementing the deficiency, such as with exercise, nutritional support, and medications and supplements. The relationship between sarcopenia and COPD is increasingly being reported, with some overlap in clinical features and treatments. We are fascinated to be able to diagnose 2 diseases through similar physical performance tests and to improve both diseases using the same treatment such as exercise. Therefore, this review summarizes the clinical relevance and integrative management of the 2 diseases.

Evaluation of muscle mass in obesity, prediabetes and diabetes mellitus by different equations used for the measurement of muscle mass

OBJECTIVE

Insulin resistance is one of risk factors for sarcopenia and there is no specific equation for the measurement of muscle mass. The present study aimed to evaluate muscle mass in the patients with obesity, prediabetes (PDM) and type 2 diabetes mellitus (DM) by different equations for the measurement of muscle mass.

METHODS

Obese patients aged 18-65 years old, who presented between 2013 and 2015 were reviewed and they were separated into three groups as obese, prediabetes (PDM) and diabetes mellitus (DM). Height, body weight, body mass index (BMI), sum of the appendicular lean masses (ALM) were measured in all participants. Body muscle mass ratio was calculated as the total muscle mass divided by the body weight, and skeletal muscle index was calculated as the total muscle mass divided by the square of the height. In addition, ALM/weight, ALM/height² and ALM/BMI ratios were also evaluated.

RESULTS

A total of 1107 participants, of whom 666 (60.2%) were female, were enrolled into the study. Of the participants, 288 (%26.02) had obesity, 524 (%47.33) had PDM and 295 (26.65%) had DM. There was a significant difference in ALM/BMI ratio between the three groups for both genders (p = 0.003 for female and p = 0.003 for male). ALM/weight ratio and body muscle mass ratio were decreased between groups in female, whereas it was no difference in male (p = 0.003, p < 0.001 for females, respectively; p = 0.802, p = 0.840 for males, respectively).

CONCLUSIONS

ALM/BMI may be more accurate for the evaluation of muscle mass in middle-aged obese, PDM and DM subjects.

Plasma Transthyretin as A Biomarker of Sarcopenia in Elderly Subjects

Skeletal muscle (SM) mass, the chief component of the structural compartment belonging to lean body mass (LBM), undergoes sarcopenia with increasing age. Decreased SM in elderly persons is a naturally occurring process that may be accelerated by acute or chronic nutritional deficiencies and/or inflammatory disorders, declining processes associated with harmful complications. A recently published position paper by European experts has provided an overall survey on the definition and diagnosis of sarcopenia in elderly persons. The present review describes the additional contributory role played by the noninvasive transthyretin (TTR) micromethod. The body mass index (BMI) formula is currently used in clinical studies as a criterion of good health to detect, prevent, and follow up on the downward trend of muscle mass. The recent upsurge of sarcopenic obesity with its multiple subclasses has led to a confused stratification of SM and fat stores, prompting workers to eliminate BMI from screening programs. As a result, investigators are now focusing on indices of protein status that participate in SM growth, maturation, and catabolism that might serve to identify sarcopenia trajectories. Plasma TTR is clearly superior to all other hepatic biomarkers, showing the same evolutionary patterns as those displayed in health and disease by both visceral and structural LBM compartments. As a result, this TTR parameter maintains positive correlations with muscle mass downsizing in elderly persons. The liver synthesis of TTR is downregulated in protein-depleted states and suppressed in cytokine-induced inflammatory disorders. TTR integrates the centrally-mediated regulatory mechanisms governing the balance between protein accretion and protein breakdown, emerging as the ultimate indicator of LBM resources. This review proposes the adoption of a gray zone defined by cut-off values ranging from 200 mg/L to 100 mg/L between which TTR plasma values may fluctuate and predict either the best or the worst outcome. The best outcome occurs when appropriate dietary, medicinal and surgical decisions are undertaken, resuming TTR synthesis which manifests rising trends towards pre-stress levels. The worst occurs when all therapeutic means fail to succeed, leading inevitably to complete exhaustion of LBM and SM metabolic resources with an ensuing fatal outcome. Some patients may remain unresponsive in the middle of the gray area, combining steady clinical states with persistent stagnant TTR values. Using the serial measurement of plasma TTR values, these last patients should be treated with the most aggressive and appropriate therapeutic strategies to ensure the best outcome.

Importance of physical evaluation using skeletal muscle mass index and body fat percentage to prevent sarcopenia in elderly Japanese diabetes patients

AIMS/INTRODUCTION

To investigate the prevalence of sarcopenia, its related factors and indicators of physical evaluation in elderly diabetes patients.

MATERIALS AND METHODS

This was a cross-sectional observation study. A total of 267 diabetes patients (159 men, 108 women) aged >65 years were recruited in the present study. Skeletal muscle mass index, grip strength and usual gait speed were measured to diagnose sarcopenia according to the Asian Working Group for Sarcopenia. Body composition was measured using bioelectrical impedance analysis. Body mass index (BMI) and body fat percentage were evaluated in quartiles to investigate the relationship with sarcopenia. A multiple logistic regression analysis examined sarcopenia-related factors.

RESULTS

The prevalence of sarcopenia in all participants was 18.7% and increased with age. Sarcopenia decreased as BMI increased (P < 0.01, Cochran-Armitage test). In contrast, the third quartile body fat percentage group showed the lowest prevalence of sarcopenia. A strong positive correlation was observed between body mass and skeletal muscle mass indices (R = 0.702-0.682). Multiple logistic regression analysis showed that sarcopenia was associated with lower BMI, non-use of metformin and lower bone mineral content in men (P < 0.05), and lower bone mineral content, lower serum levels of albumin and older age in women (P < 0.05).

CONCLUSIONS

The present study suggests that diabetes patients with a high body fat percentage in addition to low BMI might develop sarcopenia. It is suggested that physical management in elderly diabetes patients should be carried out based on the evaluation of BMI and body fat percentage to prevent sarcopenia.

Gender-specific association of body composition with inflammatory and adipose-related markers in healthy elderly Europeans from the NU-AGE study

Objectives

The aim of this work was to examine the cross-sectional relationship between body composition (BC) markers for adipose and lean tissue and bone mass, and a wide range of specific inflammatory and adipose-related markers in healthy elderly Europeans.

Methods

A whole-body dual-energy X-ray absorptiometry (DXA) scan was made in 1121 healthy (65–79 years) women and men from five European countries of the “New dietary strategies addressing the specific needs of elderly population for a healthy aging in Europe” project (NCT01754012) cohort to measure markers of adipose and lean tissue and bone mass. Pro-inflammatory (IL-6, IL-6Rα, TNF-α, TNF-R1, TNF-R2, pentraxin 3, CRP, alpha-1-acid glycoprotein, albumin) and anti-inflammatory (IL-10, TGF-β1) molecules as well as adipose-related markers such as leptin, adiponectin, ghrelin, and resistin were measured by magnetic bead-based multiplex-specific immunoassays and biochemical assays.

Results

BC characteristics were different in elderly women and men, and more favorable BC markers were associated with a better adipose-related inflammatory profile, with the exception of skeletal muscle mass index. No correlation was found with the body composition markers and circulating levels of some standard pro- and anti-inflammatory markers like IL-6, pentraxin 3, IL-10, TGF-β1, TNF-α, IL-6Rα, glycoprotein 130, TNF-α-R1, and TNF-α-R2.

Conclusions

The association between BC and inflammatory and adipose-related biomarkers is crucial in decoding aging and pathophysiological processes, such as sarcopenia. DXA can help in understanding how the measurement of fat and muscle is important, making the way from research to clinical practice.

Key Points

• Body composition markers concordantly associated positively or negatively with adipose-related and inflammatory markers, with the exception of skeletal muscle mass index.

• No correlation was found with the body composition markers and circulating levels of some standard pro- and anti-inflammatory markers like IL-6, pentraxin 3, IL-10, TGF-β1, TNF-α, IL-6Rα, gp130, TNF-α-R1, and TNF-α-R2.

• Skeletal muscle mass index (SMI) shows a good correlation with inflammatory profile in age-related sarcopenia.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5973-2) contains supplementary material, which is available to authorized users.