Decreased muscle mass and increased central adiposity are independently related to mortality in older men

Strengths and Limitations of BMI in the Diagnosis of Obesity: What is the Path Forward?

PURPOSE OF REVIEW

This review aims to discuss strengths and limitations of body mass index (BMI) in diagnosing obesity, the use of alternative anthropometric measurements, and potential new technology that may change the future of obesity diagnosis and management.

RECENT FINDINGS

The diagnosis of obesity requires the anthropometric assessment of adiposity. In clinical settings, this should include BMI with confirmation that elevated BMI represents excess adiposity and a measure of fat distribution (i.e., waist circumference (WC), waist to height ratio (WHtR), or WC divided by height0.5 (WHR.5R). Digital anthropometry and bioelectric impedance (BIA) can estimate fat distribution and be feasibly employed in the clinic. In addition, the diagnosis should include a clinical component assessing the presence and severity of weight-related complications. As anthropometric measures used in the diagnosis of obesity, BMI is generally sufficient if confirmed to represent excess adiposity, and there are advantages to the use of WHtR over WC to assess fat distribution. BIA and digital anthropometry have the potential to provide accurate measures of fat mass and distribution in clinical settings. There should also be a clinical evaluation for the presence and severity of obesity complications that can be used to stage the disease.

Analysis of behavioral change techniques used in exercise and nutritional interventions targeting adults around retirement age with sarcopenic obesity in a systematic review

BACKGROUND

Sarcopenic obesity significantly burdens health and autonomy. Strategies to intervene in or prevent sarcopenic obesity generally focus on losing body fat and building or maintaining muscle mass and function. For a lifestyle intervention, it is important to consider psychological aspects such as behavioral change techniques (BCTs) to elicit a long-lasting behavioral change.

PURPOSE

The study was carried out to analyze BCTs used in exercise and nutritional interventions targeting community-dwelling adults around retirement age with sarcopenic obesity.

METHODS

We conducted an analysis of articles cited in an existing systematic review on the effectiveness of exercise and nutritional interventions on physiological outcomes in community-dwelling adults around retirement age with sarcopenic obesity. We identified BCTs used in these studies by applying a standardized taxonomy.

RESULTS

Only nine BCTs were identified. Most BCTs were not used intentionally (82 %), and those used derived from the implementation of lifestyle components, such as exercise classes ("instructions on how to perform a behavior," "demonstration of the behavior," "behavioral practice/rehearsal," and "body changes"). Only two studies used BCTs intentionally to reinforce adherence in their interventions.

CONCLUSIONS

Few studies integrated BCTs in lifestyle interventions for community-dwelling persons around retirement age with sarcopenic obesity. Future studies on interventions to counteract sarcopenic obesity should include well-established BCTs to foster adherence and, therefore, their effectiveness.

Analysis of Endocrine and Inflammatory Markers in Preserved Ratio Impaired Spirometry

Chronic Obstructive Pulmonary Disease (COPD) is a disease of the lungs characterized by chronic airflow obstruction. Individuals with preserved ratio impaired spirometry (PRISm) may be at risk for developing COPD. This study aimed to characterize PRISm and COPD patients in terms of their immune response and endocrine profile to identify differences extending beyond lung function. The participants performed the clinical assessment, pulmonary function test, and blood collection to determine serum hormone levels and concentrations of cytokine. Differences were observed in the nutritional status, lung function, and comorbidity. There were no differences in IL-6, IL-8, IL-10, IL-12, and TNF levels between PRISm and COPD groups. Both PRISm and COPD patients have lower dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA-S) levels than controls. Correlation analysis of PRISm and COPD patients revealed positive correlations between serum levels of DHEA-S and DHEA, with forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), which negatively correlated with IL-8 levels. The results indicated that despite differences in lung function parameters, the PRISm and COPD groups exhibited similarities in endocrine profile alterations. This study represents the first attempt to link endocrine with immune markers and lung function in individuals with PRISm.

Comprehensive evaluation of body composition in a wide age range of Iranian adults using bioelectrical impedance analysis: Tehran Lipid and Glucose Study

OBJECTIVE

To evaluate sex- and age-stratified body composition (BC) parameters in subjects with wide age range of 20-79 years.

DESIGN

Cross-sectional.

SETTING

Participants of Tehran Lipid and Glucose Study (TLGS).

PARTICIPANTS

Two thousand nine hundred seventy participants met our inclusion criteria. They were divided into five age groups, and BC parameters were analysed based on sex and age using a bioelectrical impedance analyser (BIA).

RESULT

The mean age of the participants was 42·1 ± 12·5 years, and 54 % of them were males. The mean BMI was 26·7 ± 3·7 kg/m2. Obesity indices were significantly higher in females (P < 0·001); however, skeletal muscle mass (SMM) and fat-free mass (FFM) were significantly higher in males (P < 0·001). Both SMM and FFM decreased significantly after the age of 50 years. Obesity indices significantly increased from the age group of 20-29 to 30-39 years in males and the age groups of 30-39 to 40-49 years and 40-49 to 50-59 years in females. The fat mass ratio (fat mass/SMM) showed two peaks in both sexes (after the ages of 30 and 50 years in males and 40 and 50 years in females). A strong correlation was found between BMI and percentage of body fat (r = 0·823 in females v. r = 0·768 in males).

CONCLUSION

This is the first community-based study in the MENA region identifying sex- and age-stratified BC values using BIA. Our findings can be used as a reference for comparison in appropriate settings.

Association of fat mass and fat-free mass with all-cause and cause-specific mortality in Asian individuals: A prospective cohort study

OBJECTIVE

The study's objective was to investigate the association of fat mass index (FMI) and fat-free mass index (FFMI) with all-cause mortality and cause-specific mortality in the Chinese population.

METHODS

A total of 422,430 participants (48.1% men and 51.9% women) from the Taiwan MJ Cohort with an average follow-up of 9 years were included.

RESULTS

The lowest (Q1) and highest (Q5) quintiles of FMI and FFMI were associated with increased all-cause mortality. Compared with those in the third quintile (Q3) group of FMI, participants in Q1 and Q5 groups of FMI had hazard ratios and 95% CI of 1.32 (1.24-1.40) and 1.13 (1.06-1.20), respectively. Similarly, compared with those in Q3 group of FFMI, people in Q1 and Q5 groups of FFMI had hazard ratios of 1.14 (1.06-1.23) and 1.16 (1.10-1.23), respectively. In the restricted cubic spline models, both FMI and FFMI showed a J-shaped association with all-cause mortality. People in Q5 group of FFMI had a hazard ratio of 0.72 (0.58-0.89) for respiratory disease.

CONCLUSIONS

The mortality risk increases in those with excessively high or low FMI and FFMI, yet the associations between FMI, FFMI, and the risk of death varied across subgroups and causes of death.

Association of body fat distribution with all-cause and cardiovascular mortality in US adults: a secondary analysis using NHANES

OBJECTIVE

To investigate the association of fat and lean mass in specific regions with all-cause and cardiovascular-related mortality.

DESIGN

Population based cohort study.

SETTING

US National Health and Nutrition Examination Survey (2003-2006 and 2011-2018).

PARTICIPANTS

22 652 US adults aged 20 years or older.

EXPOSURES

Fat and lean mass in specific regions obtained from the whole-body dual-energy X-ray absorptiometry.

MAIN OUTCOME MEASURES

All-cause and cardiovascular-related mortality.

RESULTS

During a median of 83 months of follow-up, 1432 deaths were identified. Associations between body composition metrics and mortality risks were evident above specific thresholds. For all-cause mortality, Android fat mass showed elevated HRs above 2.46 kg (HR: 1.17, 95% CI 1.02 to 1.34), while Android lean mass (ALM) had similar trends above 2.75 kg (HR: 1.17, 95% CI 1.03 to 1.33), and Android total mass above 5.75 kg (HR: 1.08, 95% CI 1.01 to 1.16). Conversely, lower HRs were observed below certain thresholds: Gynoid fat mass (GFM) below 3.71 kg (HR: 0.72, 95% CI 0.56 to 0.93), Gynoid lean mass below 6.44 kg (HR: 0.77, 95% CI 0.64 to 0.92), and Gynoid total mass below 11.78 kg (HR: 0.76, 95% CI 0.70 to 0.84). Notably, below 0.722 kg, the HR of visceral adipose tissue mass (VATM) was 1.25 (95% CI 1.04 to 1.48) for all-cause mortality, and above 3.18 kg, the HR of total abdominal fat mass was 2.41 (95% CI 1.15 to 5.05). Cardiovascular-related mortality exhibited associations as well, particularly for Android fat mass (AFM) above 1.78 kg (HR: 1.22, 95% CI 1.01 to 1.47) and below 7.16 kg (HR: 0.50, 95% CI 0.36 to 0.69). HRs varied for Gynoid total mass below and above 10.98 kg (HRs: 0.70, 95% CI 0.54 to 0.93, and 1.12, 95% CI 1.02 to 1.23). Android per cent fat, subcutaneous fat mass (SFM), AFM/GFM, and VATM/SFM were not statistically associated with all-cause mortality. Android per cent fat, Gynoid per cent fat, AFM/GFM, and VATM/SFM were not statistically associated with cardiovascular-related mortality. Conicity index showed that the ALM/GLM had the highest performance for all-cause and cardiovascular-related mortality with AUCs of 0.785, and 0.746, respectively.

CONCLUSIONS

The relationship between fat or lean mass and all-cause mortality varies by region. Fat mass was positively correlated with cardiovascular mortality, regardless of the region in which they located. ALM/GLM might be a better predictor of all-cause and cardiovascular-related mortality than other body components or body mass index.

Low lean mass with obesity in older adults with hypertension: prevalence and association with mortality rate

BACKGROUND

The influence of sarcopenic obesity (SO) on overall survival in older adults with hypertension has not been addressed. The aim of this study was to investigate the prevalence and mortality predictive value of various body composition phenotypes, focusing mainly on SO, in older adults with hypertension.

METHODS

We included 1105 hypertensive patients aged ≥ 60 years from the National Health and Nutrition Examination Survey 1999-2004. Sarcopenia was broadly defined based on low lean mass (LLM; as measured by dual-energy X-ray absorptiometry), and was defined using appendicular lean mass (ALM) divided by height squared (ALM/height2), weight (ALM/weight), and body mass index (BMI; ALM/BMI), respectively. Obesity was defined as BMI ≥ 30 kg/m2, body fat percentage ≥ 30/42%, or waist circumference ≥ 102/88 cm. The prevalence of LLM with obesity was estimated according to each ALM index (ALMI). Multivariable Cox regression analysis and sensitivity analysis were used to examine the association between various body composition phenotypes and all-cause mortality.

RESULTS

In older adults with hypertension, the prevalence of LLM with obesity by the ALM/height2 index (9.8%) was lower relative to the ALM/weight (11.7%) and ALM/BMI indexes (19.6%). After a median follow-up of 15.4 years, 642 deaths occurred. In the fully adjusted models, LLM with obesity was significantly associated with a higher risk of all-cause mortality (hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.14-2.49, P = 0.008; HR 1.48, 95% CI 1.04-2.10, P = 0.028; HR 1.30, 95% CI 1.02-1.66, P = 0.037; respectively) compared with the normal body phenotype, with no statistical differences found in individuals with LLM or obesity alone. Sensitivity analysis confirmed the robustness of the results.

CONCLUSIONS

The prevalence of LLM with obesity markedly differed in older adults with hypertension according to the 3 different ALMIs, varying from 9.8%, 11.7%, to 19.6%. Patients with both LLM and obesity had a higher risk of all-cause mortality. Further large, prospective, cohort studies are warranted to validate these findings and uncover underlying mechanisms.

Associations between 3D surface scanner derived anthropometric measurements and body composition in a cross-sectional study

BACKGROUND

3D laser-based photonic scanners are increasingly used in health studies to estimate body composition. However, too little is known about whether various 3D body scan measures estimate body composition better than single standard anthropometric measures, and which body scans best estimate it. Furthermore, little is known about differences by sex and age.

METHODS

105 men and 96 women aged between 18 and 90 years were analysed. Bioelectrical Impedance Analysis was used to estimate whole relative fat mass (RFM), visceral adipose tissue (VAT) and skeletal muscle mass index (SMI). An Anthroscan VITUSbodyscan was used to obtain 3D body scans (e.g. volumes, circumferences, lengths). To reduce the number of possible predictors that could predict RFM, VAT and SMI backward elimination was performed. With these selected predictors linear regression on the respective body compositions was performed and the explained variations were compared with models using standard anthropometric measurements (Body Mass Index (BMI), waist circumference (WC) and waist-to-height-ratio (WHtR)).

RESULTS

Among the models based on standard anthropometric measures, WC performed better than BMI and WHtR in estimating body composition in men and women. The explained variations in models including body scan variables are consistently higher than those from standard anthropometrics models, with an increase in explained variations between 5% (RFM for men) and 10% (SMI for men). Furthermore, the explained variation of body composition was additionally increased when age and lifestyle variables were added. For each of the body composition variables, the number of predictors differed between men and women, but included mostly volumes and circumferences in the central waist/chest/hip area and the thighs.

CONCLUSIONS

3D scan models performed better than standard anthropometric measures models to predict body composition. Therefore, it is an advantage for larger health studies to look at body composition more holistically using 3D full body surface scans.

Understanding the development of sarcopenic obesity

INTRODUCTION

Sarcopenic obesity (SarcO) is defined as the confluence of reduced muscle mass and function and excess body fat. The scientific community is increasingly recognizing this syndrome, which affects a subgroup of persons across their lifespans and places them at synergistically higher risk of significant medical comorbidity and disability than either sarcopenia or obesity alone. Joint efforts in clinical and research settings are imperative to better understand this syndrome and drive the development of urgently needed future interventions.

AREAS COVERED

Herein, we describe the ongoing challenges in defining sarcopenic obesity and the current state of the science regarding its epidemiology and relationship with adverse events. The field has demonstrated an emergence of data over the past decade which we will summarize in this article. While the etiology of sarcopenic obesity is complex, we present data on the underlying pathophysiological mechanisms that are hypothesized to promote its development, including age-related changes in body composition, hormonal changes, chronic inflammation, and genetic predisposition.

EXPERT OPINION

We describe emerging areas of future research that will likely be needed to advance this nascent field, including changes in clinical infrastructure, an enhanced understanding of the lifecourse, and potential treatments.

Clinical evaluation of patients living with obesity

Obesity is a significant public health concern which is implicated in cardiometabolic disease, mechanical complications and psychiatric sequelae. BMI is currently used for diagnosis; however, it has limited sensitivity for adiposity in certain circumstances. This has led to the development of risk stratification tools like the Edmonton Staging criteria and the Kings Obesity Staging Criteria: these facilitate and guide comprehensive obesity-related complication assessment. Healthcare professionals working within obesity clinics should adopt evidence-based communication strategies, including shared decision-making, motivational interviewing, and realistic goal setting. It is also vital to avoid weight-stigmatising terminology in all aspects of care, as this can negatively impact patients. Primary care plays an essential part in obesity care and should work to promptly identify cases, initiate treatment and forward on to specialist services where appropriate. Clinical evaluation of the patient living with obesity should take a holistic approach and involve input from bariatric physicians, dietitians, psychologists, and bariatric surgeons, wider members of the multi-disciplinary team should be involved where needed. Clinicians should take a detailed history, examination and order laboratory tests to investigate for complications. Overall, with appropriate evaluation, these assessments can guide patient management and facilitate long-term improvement in health.

Regional Hypertrophy: The Effect of Exercises at Long and Short Muscle Lengths in Recreationally Trained Women

The aim of the present study was to analyse the role of exercises' resistance profile in regional hypertrophy. Thirty-eight healthy women completed a 9-week resistance training program consisting of either 4 sets of 12 repetitions to volitional failure of inclined bicep curls (INC group) or preacher curls (PREA group), three times per week. Pre- and post-intervention muscle thickness was measured using B-mode ultrasound imaging with a linear-array transducer. Scan acquisition sites were determined by measuring 50%, 60% and 70% of the distance between the posterior crest of the acromion and the olecranon. Statistical significance was set at p < 0.05. No region of the INC group grew when comparing pre- to post-intervention. The 70% region of the PREA group grew significantly (muscle thickness increased from 2.7 ± 0.43 cm to 2.94 ± 0.44 cm). We found no growth differences between regions when analysing per group (p = 0.274), region (p = 0.571) or group*region (p = 0.367). Our results show that the distal region of the arm grows in response to the preacher curl that places the highest amount of strain in the range of motion in which the arm muscles are more elongated.

Association of muscle wasting with mortality risk among adults: A systematic review and meta-analysis of prospective studies

The relationship between muscle wasting and mortality risk in the general population remains unclear. Our study was conducted to examine and quantify the associations between muscle wasting and all-cause and cause-specific mortality risks. PubMed, Web of Science and Cochrane Library were searched until 22 March 2023 for main data sources and references of retrieved relevant articles. Prospective studies investigating the associations of muscle wasting with risks of all-cause and cause-specific mortality in the general population were eligible. A random-effect model was used to calculate the pooled relative risk (RR) and 95% confidence intervals (CIs) for the lowest versus normal categories of muscle mass. Subgroup analyses and meta-regression were performed to investigate the potential sources of heterogeneities among studies. Dose-response analyses were conducted to evaluate the relationship between muscle mass and mortality risk. Forty-nine prospective studies were included in the meta-analysis. A total of 61 055 deaths were ascertained among 878 349 participants during the 2.5- to 32-year follow-up. Muscle wasting was associated with higher mortality risks of all causes (RR = 1.36, 95% CI, 1.28 to 1.44, I²  = 94.9%, 49 studies), cardiovascular disease (CVD) (RR = 1.29, 95% CI, 1.05 to 1.58, I²  = 88.1%, 8 studies), cancer (RR = 1.14, 95% CI, 1.02 to 1.27, I²  = 38.7%, 3 studies) and respiratory disease (RR = 1.36, 95% CI, 1.11 to 1.67, I²  = 62.8%, 3 studies). Subgroup analyses revealed that muscle wasting, regardless of muscle strength, was significantly associated with a higher all-cause mortality risk. Meta-regression showed that risks of muscle wasting-related all-cause mortality (P = 0.06) and CVD mortality (P = 0.09) were lower in studies with longer follow-ups. An approximately inverse linear dose-response relationship was observed between mid-arm muscle circumference and all-cause mortality risk (P < 0.01 for non-linearity). Muscle wasting was associated with higher mortality risks of all causes, CVD, cancer and respiratory disease in the general population. Early detection and treatment for muscle wasting might be crucial for reducing mortality risk and promoting healthy longevity.

Assessment of existing anthropometric indices for screening sarcopenic obesity in older adults

Sarcopenic obesity is defined as the presence of high fat mass and low muscle mass combined with low physical function, and it is closely related with the onset of cardiovasular diseases (CVD). The existing anthropometric indices, which are being utilised in clinical practice as predictors of CVD, may also be used to screen sarcopenic obesity, but their feasibility remained unknown. Using cross-sectional data of 2031 participants aged 70-84 years (mean age, 75·9 ± 3·9 years; 49·2 % women) from the Korean Frailty and Aging Cohort Study, we analysed the association of anthropometric indices, including body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR) and weight-adjusted waist index (WWI) with sarcopenic obesity. Body composition was measured using dual-energy X-ray absorptiometry. Higher WWI, WHtR and WC quartiles were associated with higher risk of sarcopenic obesity; the odds ratio (OR) of sarcopenic obesity were highest in the fourth quartile of the WWI (OR: 10·99, 95 % CI: 4·92-24·85, P_{for trend} < 0·001). WWI provided the best diagnostic power for sarcopenic obesity in men (area under the receiver operating characteristic curve: 0·781, 95 % CI: 0·751-0·837). No anthropometric indices were significantly associated with sarcopenic obesity in women. WWI was the only index that was negatively correlated with physical function in both men and women. WWI showed the strongest association with sarcopenic obesity, defined by high fat mass and low muscle mass combined with low physical function only in older men. No anthropometric indices were associated with sarcopenic obesity in older women.

Associations of Total Body Fat Mass and Skeletal Muscle Index with All-Cause and Cancer-Specific Mortality in Cancer Survivors

Purpose: The importance of body composition on cancer outcomes is of great clinical interest. Measures of body composition that differentiate fat mass from skeletal muscle mass can help redefine our understanding of body composition for cancer survival. We investigated whether the risk of all-cause and cancer-specific mortality differ by levels of total fat mass and sarcopenia status in cancer survivors. Our secondary aim was a subgroup analysis assessing the role of race within these associations. Methods: Participants included 1682 adult cancer survivors who had undergone a dual-energy X-ray absorptiometry (DXA) examination to measure body composition, from the 1999-2006 and 2011-2018 National Health and Nutrition Examination Survey (NHANES). Total fat mass was categorized into tertiles (we assessed high vs. low tertiles), and sarcopenia was considered as having an appendicular skeletal muscle mass index less than 7.26 kg/m2 for males and less than 5.45 kg/m2 for females. Multivariable Cox proportional hazard models estimated the adjusted hazard ratio (aHR) and 95% confidence interval (CI). Results: The mean age of study participants was 61.9 years, and they were followed up for an average of 9.67 years. The prevalence of sarcopenia was 25.0% (N = 304), and 33.4% (N = 561) had a high total fat mass. Participants with a higher fat mass (aHR = 1.30, 95% CI = 1.06-1.61) and with sarcopenia (aHR = 1.51, 95% CI = 1.22-1.88) had a 30% and 51% increased risk of all-cause mortality compared to participants with a low fat mass and with no sarcopenia, respectively. Further, sarcopenia (aHR = 1.74, 95% CI = 1.23-2.29) was associated with a higher risk of cancer-specific mortality in cancer survivors. The association between sarcopenia and all-cause mortality was twice as strong in Black people (aHR = 2.99, 95% CI = 1.39-6.06) compared to White people (aHR = 1.53, 95% CI = 1.19-1.95). Conclusions: Our findings show the opposing relations of fat mass and appendicular skeletal muscle mass index with mortality in a national sample of cancer survivors, and that the relationships may differ by race. These results emphasize the importance of maintaining a healthy body composition among cancer survivors.

Mid-upper Arm Circumference as an Indicator of Quality of Life of Patients with Advanced Cancer

OBJECTIVE

Mid-upper arm circumference (MUAC) has been used to assess malnutrition and health status across various disease groups. However, it is unclear whether MUAC is associated with quality of life (QOL) of patients with advanced cancer. Our goal was to investigate the relationship between MUAC and QOL in ambulatory out-patients with advanced cancer.

METHOD

This was a cross-sectional study conducted in a tertiary cancer center in South Korea. A total of 200 patients with advanced cancer at oncology clinics of Seoul National University Bundang Hospital from March 2016 to January 2019 were enrolled. Out-patients with advanced cancer whose survival was expected to be less than one year by their oncologists were enrolled. QOL of patients was evaluated using the European Organization for Research and Treatment of Cancer quality of life questionnaire core 30 (EORTC QLQ-C30). Associations of QOL with MUAC and nutritional parameters were examined with generalized linear models.

RESULTS

The most common cancer sites were the lung, colon or rectum, and genitourinary tract. In univariate analyses, significant factors associated with higher summary score of EORTC QLQ-C30 were higher MUAC (≥ 26.5 cm, p < 0.001), higher body mass index (BMI) (≥ 22 kg/m², p < 0.001), higher serum albumin (≥ 3.7 g/dL, p < 0.01), higher creatinine (≥ 0.8 mg/dL, p = 0.023), and higher uric acid (≥ 5 mg/dL, p < 0.01). In multivariate analysis, higher serum albumin (≥ 3.7 g/dL, p < 0.01) and higher MUAC (≥ 26.5 cm, p = 0.03) were independently associated with better summary score of EORTC QLQ-C-30.

CONCLUSION

MUAC was highly associated with QOL in terms of summary score and overall health status. Thus, MUAC, with its simplicity, can be a useful tool to reflect QOL in patients with advanced cancer.

Dominant-negative p53-overexpression in skeletal muscle induces cell death and fiber atrophy in rats

The tumor suppressor p53 is thought to play a key role in the maintenance of cell size and homeostasis, but relatively little is known about its role in skeletal muscle. Based on its ability to suppress cell growth, we hypothesized that inhibiting the function of wild-type p53 through the overexpression of a dominant-negative p53 mutant (DDp53) could result in muscle fiber hypertrophy. To test this hypothesis, we electroporated adult rat tibialis anterior muscles with DDp53 and collected the tissue three weeks later. We confirmed successful overexpression of DDp53 on a histological and biochemical level and found pronounced changes to muscle architecture, metabolism, and molecular signaling. Muscle mass, fiber cross-sectional area, and fiber diameter significantly decreased with DDp53 overexpression. We found histopathological changes in DDp53 transfected muscle which were accompanied by increased levels of proteins that are associated with membrane damage and repair. In addition, DDp53 decreased oxidative phosphorylation complex I and V protein levels, and despite its negative effects on muscle mass and fiber size, caused an increase in muscle protein synthesis as assessed via the SUnSET technique. Interestingly, the increase in muscle protein synthesis was concomitant with a decrease in phospho-S6K1 (Thr389). Furthermore, the muscle wasting in the DDp53 electroporated leg was accompanied by a decrease in global protein ubiquitination and an increase in proteasome activity. In conclusion, overexpression of a dominant-negative p53 mutant in skeletal muscle results in decreased muscle mass, myofiber size, histological muscle damage, a metabolic phenotype, and perturbed homeostasis between muscle protein synthesis and degradation.

Magnesium Intake, C-Reactive Protein, and Muscle Mass in Adolescents

Background: Adult studies have suggested that magnesium intake may regulate C-reactive protein (CRP) and muscle mass, known risk factors for cardiometabolic diseases. Given the large deficiencies in magnesium intake in adolescents, we aimed to investigate sex and race differences in dietary magnesium intake and test the hypothesis that lower magnesium intake is associated with higher CRP and lower muscle mass. Methods: A total of 766 black and white adolescents, 14 to 18 years old (51% black; 50% female) were previously recruited. Diet was assessed with four to seven independent 24-h recalls. Body composition was measured by dual-energy X-ray absorptiometry. High-sensitivity CRP (hs-CRP), leptin, resistin, and adiponectin were measured using fasting blood samples by ELISA. Results: There were sex and race differences in the daily consumption of magnesium. The average daily magnesium intakes were 200.66 ± 7.09 mg and 205.03 ± 7.05 mg for males and females, respectively, far below the recommended amounts of 410 mg for males and 360 mg for females. White subjects (217.95 ± 6.81 mg/day) consumed more than black subjects (187.75 ± 6.92 mg/day). Almost none of the adolescents met the recommendations. Adjusted multiple linear regressions revealed that lower magnesium intake was associated with higher hs-CRP and lower fat-free mass (FFM) (p-values < 0.05). Higher hs-CRP was associated with lower FFM. Moreover, an interaction between magnesium intake and hs-CRP on FFM was identified (p-value < 0.05). Lower magnesium intake amplified the inverse relationships between hs-CRP and FFM (p-values < 0.05). Conclusion: Magnesium consumption in our adolescents was far below daily recommended levels with male and black subjects consuming less than female and white subjects. Lower magnesium intake was associated with higher CRP and lower muscle mass. Low magnesium intake may also augment the inverse relationship between CRP and FFM.

Body fat and risk of all-cause mortality: a systematic review and dose-response meta-analysis of prospective cohort studies

BACKGROUND/OBJECTIVES

We aimed to evaluate the relationships between body fat percentage (BF%), fat mass (FM), fat mass index (FMI) and visceral (VAT) and subcutaneous adipose tissue (SAT) with risk of all-cause mortality.

METHODS

We did a systematic search in PubMed, Scopus, and Web of Science to June 2021. We selected prospective cohorts of the relationship between body fat with risk of all-cause mortality in the general population. We applied random-effects models to calculate the relative risks (RRs) and 95%CIs.

RESULTS

A total of 35 prospective cohort studies with 923,295 participants and 68,389 deaths were identified. The HRs of all-cause mortality for a 10% increment in BF were 1.11 (95%CI: 1.02, 1.20; I² = 93%, n = 11) in the general adult populations, and 0.92 (95%CI: 0.79, 1.06; I² = 76%, n = 7) in adults older than 60 years. The HRs were 1.06 (95%CI: 1.01, 1.12; I² = 86%, n = 10) for a 5 kg increment in FM, 1.11 (95%CI: 1.06, 1.16; I² = 79%, n = 7) for a 2 kg/m² increment in FMI, and 1.17 (95%CI: 1.03, 1.33; I² = 72%, n = 8) and 0.81 (0.66, 0.99; I² = 59%, n = 6) for a 1-SD increment in VAT and SAT, respectively. There was a J shaped association between BF% and FM and all-cause mortality risk, with the lowest risk at BF% of 25% and FM of 20 kg. In subgroup analyses, although there was little evidence of between-subgroup heterogeneity, the observed positive associations were more pronounced in studies which had a longer duration, excluded participants with prevalent cardiovascular disease and cancer at baseline, with adjustment for smoking or restricted to never smokers, and less pronounced in studies which adjusted for potential intermediates, suggesting an impact of reverse causation, confounding and over-adjustment in some of the studies.

CONCLUSIONS

Higher body fat content was related to a higher risk of mortality in a J shaped manner. Any future studies should further assess the impact of reverse causation and residual confounding on these associations.

REGISTRATION

PROSPERO (CRD42021240743).

The role of the neural stimulus in regulating skeletal muscle hypertrophy

Resistance training is frequently performed with the goal of stimulating muscle hypertrophy. Due to the key roles motor unit recruitment and mechanical tension play to induce muscle growth, when programming, the manipulation of the training variables is oriented to provoke the correct stimulus. Although it is known that the nervous system is responsible for the control of motor units and active muscle force, muscle hypertrophy researchers and trainers tend to only focus on the adaptations of the musculotendinous unit and not in the nervous system behaviour. To better guide resistance exercise prescription for muscle hypertrophy and aiming to delve into the mechanisms that maximize this goal, this review provides evidence-based considerations for possible effects of neural behaviour on muscle growth when programming resistance training, and future neurophysiological measurement that should be tested when training to increase muscle mass. Combined information from the neural and muscular structures will allow to understand the exact adaptations of the muscle in response to a given input (neural drive to the muscle). Changes at different levels of the nervous system will affect the control of motor units and mechanical forces during resistance training, thus impacting the potential hypertrophic adaptations. Additionally, this article addresses how neural adaptations and fatigue accumulation that occur when resistance training may influence the hypertrophic response and propose neurophysiological assessments that may improve our understanding of resistance training variables that impact on muscular adaptations.

Impact of Sarcopenia on the Severity of the Liver Damage in Patients With Non-alcoholic Fatty Liver Disease

An extensive body of the literature shows a strong interrelationship between the pathogenic pathways of non-alcoholic fatty liver disease (NAFLD) and sarcopenia through the muscle-liver-adipose tissue axis. NAFLD is one of the leading causes of chronic liver diseases (CLD) affecting more than one-quarter of the general population worldwide. The disease severity spectrum ranges from simple steatosis to non-alcoholic steatohepatitis (NASH), cirrhosis, and its complications: end-stage chronic liver disease and hepatocellular carcinoma. Sarcopenia, defined as a progressive loss of the skeletal muscle mass, reduces physical performances, is associated with metabolic dysfunction and, possibly, has a causative role in NAFLD pathogenesis. Muscle mass is a key determinant of the whole-body insulin-mediated glucose metabolism and impacts fatty liver oxidation and energy homeostasis. These mechanisms drive the accumulation of ectopic fat both in the liver (steatosis, fatty liver) and in the muscle (myosteatosis). Myosteatosis rather than the muscle mass per se, seems to be closely associated with the severity of the liver injury. Sarcopenic obesity is a recently described entity which associates both sarcopenia and obesity and may trigger worse clinical outcomes including hepatic fibrosis progression and musculoskeletal disabilities. Furthermore, the muscle-liver-adipose tissue axis has a pivotal role in changes of the body composition, resulting in a distinct clinical phenotype that enables the identification of the "sarcopenic NAFLD phenotype." This review aims to bring some light into the complex relationship between sarcopenia and NAFLD and critically discuss the key mechanisms linking NAFLD to sarcopenia, as well as some of the clinical consequences associated with the coexistence of these two entities: the impact of body composition phenotypes on muscle morphology, the concept of sarcopenic obesity, the relationship between sarcopenia and the severity of the liver damage and finally, the future directions and the existing gaps in the knowledge.

Social relationships and the risk of incident heart failure: results from a prospective population-based study of older men

Aims

Limited social relationships, particularly in older adults, have been implicated as a risk factor for cardiovascular disease. However, little is known about the associations between poor social relationships and heart failure incidence.

Methods and results

Prospective study of socially representative men aged 60–79 years drawn from general practices in 24 British towns and followed up for a maximum of 18 years. A total of 3698 participants with no previous diagnosis of heart failure were included. Information on social relationships was based on a combination of marital status, living circumstances, and social contacts with friends and family. These provided information on contact frequency, contact satisfaction, and a social relationship score (low to high) combining frequency and satisfaction with contact. Heart failure included both incidents non-fatal heart failure and death from heart failure. Among 3698 participants, 330 developed heart failure. Men with low compared to high frequency of contact with family and friends had an increased risk of incident heart failure [hazard ratio (HR) 1.59, 95% confidence interval (CI) 1.15–2.18]; this remained statistically significant after adjustment for social class, behavioural, and biological risk factors. Low compared to high scores for satisfaction with contacts was associated with increased risk of heart failure (adjusted HR = 1.54; 95% CI 1.14–2.07). Lower social relationship scores (combining frequency and satisfaction with contact) were associated with greater risk of incident heart failure (adjusted HR = 1.38, 95% CI 1.02–1.87). Marital status and living alone were not significantly associated with heart failure.

Conclusion

Weaker social relationships appear to increase the risk of developing heart failure in older age. Further research is needed to investigate pathways underlying these associations and to test whether interventions to strengthen social relationships can reduce the risk of heart failure.

Body Composition and Incident Heart Failure in Older Adults: Results From 2 Prospective Cohorts

Background Aging is associated with central fat redistribution and skeletal muscle decline, yet the relationships of tissue compartments with heart failure (HF) remain incompletely characterized. We assessed the contribution of body composition to incident HF in elders. Methods and Results Participants from 2 older cohorts who completed dual-energy X-ray absorptiometry (DEXA) and, in one cohort, computed tomography were included. We evaluated associations with incident HF for DEXA principal components (PCs) and total lean, appendicular lean, total fat and trunk fat mass; and for computed tomography measures of abdominal visceral and subcutaneous fat, thigh muscle, intermuscular fat area and thigh muscle density. DEXA analysis included 3621, and computed tomography analysis 2332 participants. During median follow-up of 11.8 years, 927 participants developed HF. DEXA principal components showed no relationship with HF. After adjustment for height, weight, and cardiovascular risk factors, total lean mass was near significantly associated with higher HF (hazard ratio [HR], 1.25 per SD [1.00-1.56]), whereas total fat mass and thigh muscle density were significantly related to lower HF (HR, 0.82 [0.68-0.99] and HR, 0.87 [0.78-0.97], respectively). Patterns were similar for HF subtypes. The relationships with HF for total lean and fat mass were attenuated after adjusting for intercurrent atrial fibrillation or excluding high natriuretic peptide levels. Conclusions Total lean mass was positively associated, while total fat mass and thigh muscle density were inversely associated, with incident HF. These findings highlight the limitations of DEXA for assessment of HF risk in elders and support the preeminence of computed tomography-measured skeletal muscle quality over mass as a determinant of HF incidence.

Indicators of Obesity and Cardio-metabolic Risks: Important Consideration in Adults and Children

The prevalence of obesity has dramatically increased all over the world. Body mass index (BMI) has been used as the most common available measure to determining obesity status. While the site of excessive fat mass accumulation is a stronger determinant of cardio-metabolic complication, with respect to systemic and generalized obesity, which is only determined through BMI. So, it is concluded that using traditional anthropometric indices such as BMI for interpreting the obesity status and cardio-metabolic risk has considerable limitations. Thus, the main aims of the present study are to discuss possible drawbacks of anthropometric indices especially BMI, which in epidemiological studies are usually neglected, as well as lend important consideration to using other anthropometric indices such as measurement of obesity and related cardio-metabolic complications with a special emphasis on the use of waist circumference, waist-to-hip ratio and waist-to-height ratio.

Artificial neural network model effectively estimates muscle and fat mass using simple demographic and anthropometric measures

BACKGROUND & AIMS

Lean muscle and fat mass in the human body are important indicators of the risk of cardiovascular and metabolic diseases. Techniques such as dual-energy X-ray absorptiometry (DXA) accurately measure body composition, but they are costly and not easily accessible. Multiple linear regression (MLR) models have been developed to estimate body composition using simple demographic and anthropometric measures instead of expensive techniques, but MLR models do not explore nonlinear interactions between inputs. In this study, we developed simple demographic and anthropometric measure-driven artificial neural network (ANN) models that can estimate lean muscle and fat mass more effectively than MLR models.

METHODS

We extracted the demographic, anthropometric, and body composition measures of 20,137 participants from the National Health and Nutrition Examination Survey conducted between 1999 and 2006. We included 13 demographic and anthropometric measures as inputs for the ANN models and divided the dataset into training and validation sets (70:30 ratio) to build and cross-validate the models that estimate lean muscle and fat mass, which were originally measured using DXA. This process was repeated 100 times by randomly dividing the training and validation sets to eliminate any effect of data division on model performance. We built additional models separately for each sex and ethnicity, older individuals, and people with underlying diseases. The coefficient of determination (R²) and standard error of estimate (SEE) were used to quantify the goodness of fit.

RESULTS

The ANN models yielded high R² values between 0.923 and 0.981. These values were significantly higher than those of the MLR models (p < 0.001) in all cases. The percentage difference in R² between the ANN and MLR models ranged between 0.40% ± 0.02% and 2.65% ± 0.27%. The SEE values of the ANN models, which were below 2 kg for all cases, were significantly lower than those of MLR models (p < 0.001). The percentage difference in SEE values between the ANN and MLR models ranged between -5.67% ± 0.39% and -22.32% ± 1.98%.

CONCLUSIONS

We developed and validated an inexpensive but effective method for estimating body composition using easily obtainable demographic and anthropometric data.

Low-cost and fast-performing indicators of muscle mass loss are good predictors of clinical outcomes in hospitalized patients: A longitudinal observational study

BACKGROUND

"Gold standard" methods for muscle mass (MM) assessment are expensive and difficult to use in clinical practice. The present study aimed to evaluate the association between easy-to-apply and low-cost indicators of MM and clinical outcomes in hospitalized patients.

METHODS

In this cohort study, calf circumference [CC], adductor pollicis muscle thickness [APMT], midarm muscle circumference [MAMC], and arm muscle area [AMA] were measured within 48 h of admission to detect MM loss, and it was also evaluated by physical examination. Patients were followed up until discharge for collection of in-hospital death and length of hospital stay (LOS) data, and they were contacted by phone to assess hospital readmission and mortality at 6 months after discharge.

RESULTS

We evaluated 601 patients (55.8 ± 14.8 years). Moderate/severe loss of MM (hazard ratio [HR], 4.12; 95% CI, 1.26-13.49), low CC (HR, 3.67; 95% CI: 1.07-12.55), low MAMC (HR, 5.20; 95% CI, 1.48-18.35), and low AMA (HR, 14.28; 95% CI, 1.80-113.14) were predictors of in-hospital mortality. Moderate/severe loss of MM was a predictor of prolonged LOS (odds ratio [OR], 2.27; 95% CI, 1.53-3.36), hospital readmission (OR, 4.14; 95% CI, 1.26-13.55), and mortality at 6 months (OR, 3.20; 95% CI, 1.71-6.01). Low CC (OR, 2.49; 95% CI, 1.27-4.85) and low APMT (OR, 3.22; 95% CI, 1.56-6.66) were associated with death 6 months after discharge.

CONCLUSION

Easy-to-apply and low-cost indicators of MM were associated with negative clinical outcomes and should be part of nutrition assessment in hospitals.

Association of body composition with functional capacity and cognitive function in older adults living in nursing homes

BACKGROUND

Older adults living in nursing homes have an increased risk of adverse outcomes. However, the role of body composition in vital health and quality of life parameters such as functional capacity and cognitive function is less studied in this group of older adults compared to community-dwelling counterparts.

OBJECTIVE

The aim of the present study was to examine the association of body composition with functional capacity and cognitive function in nursing home residents.

METHODS

Fifty-three older adults (82.8±7.3 years) were enrolled in this study and they underwent body composition evaluation, functional capacity and cognitive function measurements.

RESULTS

The results showed a high prevalence of obesity accompanied by functional capacity limitations and cognitive impairment in older adults living in nursing homes. Partial correlations, controlling for age, showed that body fat percentage was positively correlated with sit-to-stand-5 (r=0.310, p=0.025) and timed-up-and-go (r=0.331, p=0.017), and negatively correlated with handgrip strength test results (r=-0.431, p<0.001), whereas greater lean body mass was associated with better sit-to-stand-5 (r=-0.410, p=0.003), handgrip strength (r=0.624, p<0.001) and cognitive function performance (r=0.302, p=0.037).

CONCLUSIONS

These important associations reinforce the need to develop effective healthy lifestyle interventions targeting both lean mass and body fat to combat functional and cognitive decline in nursing home residents.

Targeting cancer via ribosome biogenesis: the cachexia perspective

Cancer cachexia afflicts many advanced cancer patients with many progressing to death. While there have been many advancements in understanding the molecular mechanisms that contribute to the development of cancer cachexia, substantial gaps still exist. Chemotherapy drugs often target ribosome biogenesis to slow or blunt tumor cell growth and proliferation. Some of the most frequent side-effects of chemotherapy are loss of skeletal muscle mass, muscular strength and an increase in fatigue. Given that ribosome biogenesis has emerged as a main mechanism regulating muscle hypertrophy, and more recently, also implicated in muscle atrophy, we propose that some chemotherapy drugs can cause further muscle wasting via its effect on skeletal muscle cells. Many chemotherapy drugs, including the most prescribed drugs such as doxorubicin and cisplatin, affect ribosomal DNA transcription, or other pathways related to ribosome biogenesis. Furthermore, middle-aged and older individuals are the most affected population with cancer, and advanced cancer patients often show reduced levels of physical inactivity. Thus, aging and inactivity can themselves affect muscle ribosome biogenesis, which can further worsen the effect of chemotherapy on skeletal muscle ribosome biogenesis and, ultimately, muscle mass and function. We propose that chemotherapy can accelerate the onset or worsen cancer cachexia via its inhibitory effects on skeletal muscle ribosome biogenesis. We end our review by providing recommendations that could be used to ameliorate the negative effects of chemotherapy on skeletal muscle ribosome biogenesis.

Differential Responses of White Adipose Tissue and Brown Adipose Tissue to Calorie Restriction During Aging

Age-related adipose tissue dysfunction is potentially important in the development of insulin resistance and metabolic disorder. Caloric restriction (CR) is a robust intervention to reduce adiposity, improve metabolic health, and extend healthy life span. Both white adipose tissue (WAT) and brown adipose tissue (BAT) are involved in energy homeostasis. CR triggers the beiging of WAT in young mice; however, the effects of CR on beiging of WAT and function of BAT during aging are unclear. This study aimed to investigate how age and CR impact the beiging of WAT, the function of BAT, and metabolic health in mice. C57BL/6 mice were fed CR diet (40% less than the ad libitum [AL] diet) for 3 months initiated in young (3 months), middle-aged (12 months), and old (19 months) stage. We found age-related changes in different types of adipose tissue, including adipocyte enlargement, declined beiging of WAT, and declined thermogenic and β-oxidational function of BAT. Moreover, CR attenuated age-associated adipocyte enlargement and prevented the age-related decline in beiging potential of WAT. These protective effects on the beiging potential were significant in inguinal WAT at all three ages, which were significant in epididymal WAT at young and old age. In contrast, thermogenic and β-oxidational function of BAT further declined after CR in the young age group. In conclusion, our findings reveal the contribution of WAT beiging decline to age-related metabolic disorder and suggest nutritional intervention, specifically targeting WAT beiging, as an effective approach to metabolic health during aging.

A Prognostic Model to Facilitate Palliative Care Referral in Oncology Outpatients

Purpose

We aimed to develop a prognostic model to assist palliative care referral at least 3 months before death in advanced cancer patients treated at an outpatient medical oncology clinic.

Materials and Methods

In this prospective cohort study, a total of 200 patients were enrolled at a tertiary cancer center in South Korea. The major eligibility criterion was an expected survival of less than a year as estimated by their oncologists. We analyzed the influences of known prognostic factors along with chemotherapy status, mid-arm circumference, and triceps skinfold thickness on survival time.

Results

The mean age of the patients was 64.5 years, 36% were female, and the median survival time was 7.6 months. In the multivariate analysis, we found six significant factors related to poor survival: a poor Eastern Cooperative Oncology Group (ECOG) performance status (≥ 2), not undergoing chemotherapy, anorexia, a low lymphocyte level (< 12%), a high lactate dehydrogenase (LDH) level (≥ 300 IU/L), and a low mid-arm circumference (< 23 cm). We developed a prognostic model (score, 0–8.0) to predict 3-month survival based on the multivariate analysis. Patients who scored ≥ 4.0 points had a short survival of less than 3 months (p < 0.001). The discriminating ability of the prognostic model using the area under the receiver operating characteristic curve was 0.88.

Conclusion

The prognostic model using ECOG performance status, chemotherapy status, anorexia, lymphocytes, LDH, and mid-arm circumference can predict 3-month survival in medical oncology outpatients. It can alert oncologists to refer patients to palliative care specialists before it is too late.

Mid-Arm Muscle and Subcutaneous Fat Associated with All-Cause Mortality Independent of BMI: A Prospective Cohort Study

OBJECTIVE

This study aimed to systematically evaluate the association between triceps skinfold (TSF) thickness (which indicates subcutaneous fat) mid-arm muscle circumference (MAMC; which reflects muscle mass), mid-upper arm circumference (MUAC), and all-cause mortality.

METHODS

A total of 17,717 adults from the China Health and Nutrition Survey (1993-2015) were included. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality. The joint effect of TSF thickness and MAMC was examined, and planned subgroup analyses were performed.

RESULTS

The highest quartiles of TSF thickness, MAMC, and MUAC were significantly associated with low all-cause mortality, independent of BMI (TSF thickness: HR = 0.704 [95% CI: 0.575-0.862]; MAMC: HR = 0.729 [95% CI: 0.607-0.876]; MUAC: HR = 0.713 [95% CI: 0.583-0.872]). A 1-SD increase showed comparable risk reductions for TSF thickness and MAMC (14.6% and 14.0%), with 16.1% risk reductions in MUAC. There were positive additive interactions between TSF thickness and MAMC. The inverse association existed in young, middle-aged, and elderly participants (P-heterogeneity > 0.05).

CONCLUSIONS

Mid-arm muscle and subcutaneous fat were inversely associated with all-cause mortality, independent of BMI, beyond the elderly population. Mid-arm muscle and subcutaneous fat made comparable contributions to and had positive joint effects on all-cause mortality.

Can conditions of skeletal muscle loss be improved by combining exercise with anabolic-androgenic steroids? A systematic review and meta-analysis of testosterone-based interventions

Sarcopenia, cachexia, and atrophy due to inactivity and disease states are characterized by a loss of skeletal muscle mass, often accompanied by reduced levels of anabolic hormones (e.g. testosterone). These conditions are associated with an increase in mortality, hospitalization and worsening in quality of life. Both physical exercise (EX) and anabolic-androgenic steroid (AAS) administration can improve the prognosis of patients as they increase physical functionality. However, there is a gap in the literature as to the impact of these therapies on the gains in strength and muscle mass and their implications for patient safety. Accordingly, we performed a random-effects meta-analysis to elucidate the effects of AAS and/or EX interventions on lean body mass (LBM) and muscle strength in conditions involving muscle loss. A systematic search for relevant clinical trials was conducted in MEDLINE, EMBASE, SCOPUS, Web of Science, and SPORTDiscus. Comparisons included AAS vs. Control, EX vs. Control, AAS vs. EX, AAS + EX vs. AAS and AAS + EX vs. EX. A total of 1114 individuals were analyzed. AAS increased LBM (effect size [ES]: 0.46; 95% CI: 0.25, 0.68, P = 0.00) and muscle strength (ES: 0.31; 95% CI: 0.08, 0.53, P = 0.01) when compared to a control group. EX promoted an increase in muscular strength (ES: 0.89; 95% CI: 0.53, 1.25, P = 0.00), with no effect on LBM when compared to the control group (ES: 0.15; 95% CI: -0.07, 0.38, P = 0.17). AAS did not demonstrate statistically significant differences when compared to EX for LBM and muscle strength. The combination of EX + AAS promoted a greater increase in LBM and muscular strength when compared to AAS or EX in isolation. Qualitatively, AAS administration had relatively few side effects. Significant heterogeneity was found in some analyses, which may be explained by the use of different AAS types and EX protocols. Our findings suggest that AAS administration in cachectic and sarcopenic conditions may be a viable interventional strategy to enhance muscle function when exercise is not a possible approach. Moreover, combining AAS with exercise may enhance positive outcomes in this population.

Serum creatinine to cystatin C ratio is associated with major adverse cardiovascular events in patients with obstructive coronary artery disease

BACKGROUND & AIMS

Sarcopenia is a clinical syndrome that features muscle atrophy and weakness, and has been associated with cardiovascular events and poor clinical outcomes. Recently, the sarcopenia index (SI) was developed as a simple screening tool based upon the serum creatinine to cystatin C (CysC) ratio. We investigated the association between SI and the prevalence of major adverse cardiovascular events (MACE) in patients with obstructive CAD.

METHODS & RESULTS

Between January 2010 and December 2018, patients with angina pectoris and obstructive CAD requiring coronary artery intervention were enrolled. Serum levels of CysC and other biomarkers were assessed. Patients were divided into two groups according to the SI ([Cr/CysC] x 100). Demographic characteristics and clinical outcomes of the two groups were evaluated. A total of 427 patients (79.6% men, mean age 69.55 ± 12.04 years) were enrolled. Patients with SI < 120 (n = 214, 28%) were older, more likely to be of the female gender, and to have more hypertension and congestive heart failure (all p < 0.05). The prevalence of major adverse cardiovascular events (MACE) composed of myocardial infarction, stroke, and all-cause mortality was higher in patients with lower SI (p = 0.026). After adjusting for potential confounding factors, multivariate Cox regression (hazard ratio 2.08, p = 0.045) and Kaplan-Meier analyses (log-rank p = 0.0371) revealed that lower SI was significantly associated with a higher prevalence of MACE.

CONCLUSIONS

Serum creatinine to cystatin C ratio (SI) may be a useful surrogate marker to predict the future prevalence of MACE in patients with obstructive CAD.

Weight-adjusted waist index reflects fat and muscle mass in the opposite direction in older adults

BACKGROUND

Age-related changes in body composition include decreased muscle mass and preserved or increased fat mass. There is no anthropometric index to assess both muscle and fat mass.

METHODS

Using a cross-sectional sample of 602 participants aged ≥65 years from the Ansan Geriatric study, we evaluated the association of weight-adjusted waist index (WWI) with muscle and fat mass and compared these with body mass index (BMI) and waist circumference (WC). WWI was calculated as WC (cm) divided by the square root of body weight (kg). Body composition was measured using bioelectrical impedance analysis, dual-energy X-ray absorptiometry and abdominal computed tomography.

RESULTS

WWI positively correlated with total abdominal fat area (TFA) (r = 0.421, P < 0.001), visceral fat area (VFA) (r = 0.264, P < 0.001), and percentage of total tissue fat (r = 0.465, P < 0.001), but negatively correlated with appendicular skeletal muscle mass (ASM) (r = -0.511, P < 0.001) and ASM/height2 (r = -0.324, P < 0.001). Mean ASM was highest in the first quartile of WWI (17.85 kg/m2) and showed a decreasing trend, with the lowest value in the fourth WWI quartile (13.21 kg/m2, P for trend <0.001). In contrast, mean TFA was lowest in the first quartile and highest in the fourth WWI quartile (P for trend <0.001). The probability of combined low muscle mass and high fat mass was >3× higher in the fourth WWI quartile than in the lowest quartile (odds ratio 3.22, 95% confidence interval 1.32-7.83).

CONCLUSIONS

WWI is an anthropometric index positively associated with fat mass and negatively associated with muscle mass in older adults.

Associations of Skeletal Muscle Mass and Fat Mass With Incident Cardiovascular Disease and All-Cause Mortality: A Prospective Cohort Study of UK Biobank Participants

Background There is debate whether body mass index is a good predictor of health outcomes because different tissues, namely skeletal muscle mass (SMM) and fat mass (FM), may be differentially associated with risk. We investigated the association of appendicular SMM (aSMM) and FM with fatal and nonfatal cardiovascular disease (CVD) and all-cause mortality. We compared their prognostic value to that of body mass index. Methods and Results We studied 356 590 UK Biobank participants aged 40 to 69 years with bioimpedance analysis data for whole-body FM and predicted limb muscle mass (to calculate aSMM). Associations between aSMM and FM with CVD and all-cause mortality were examined using multivariable Cox proportional hazards models. Over 3 749 501 person-years of follow-up, there were 27 784 CVD events and 15 844 all-cause deaths. In men, aSMM was positively associated with CVD incidence (hazard ratio [HR] per 1 SD 1.07; 95% CI, 1.06-1.09) and there was a curvilinear association in women. There were stronger positive associations between FM and CVD with HRs per SD of 1.20 (95% CI, 1.19-1.22) and 1.25 (95% CI, 1.23-1.27) in men and women respectively. Within FM tertiles, the associations between aSMM and CVD risk largely persisted. There were J-shaped associations between aSMM and FM with all-cause mortality in both sexes. Body mass index was modestly better at discriminating CVD risk. Conclusions FM showed a strong positive association with CVD risk. The relationship of aSMM with CVD risk differed between sexes, and potential mechanisms need further investigation. Body fat and SMM bioimpedance measurements were not superior to body mass index in predicting population-level CVD incidence or all-cause mortality.

Predictors of Sarcopenia in an Obese Asian Population

Sarcopenia is associated with obesity and might also be responsible for other disorders. Here, we investigated the prevalence of sarcopenia and its predictors in obese subjects. Subjects who underwent a medical health checkup and living-related liver donors were recruited. Obesity was defined as body mass index (BMI) ≥25 kg/m². Muscle mass was assessed using computed tomography at the 3^rd lumbar vertebra. The lowest quartile of the lumbar skeletal muscle index (LSMI) was considered sarcopenia. Among 466 obese subjects, 53 (11.4%) had sarcopenia. Subjects with sarcopenia were significantly older (mean 66.6 vs. 53.3 years) and had a significantly higher prevalence of hypertension (62.3 vs. 46.0%) and diabetes (45.3 vs. 31.0%), higher fibrosis-4 (FIB-4) index (mean 1.57 vs. 1.16), and higher atherosclerotic cardiovascular disease (ASCVD) risk score (mean 22.86% vs. 11.15%), whereas they had a significantly lower prevalence of female gender (13.2% vs. 27.8%), lower BMI (mean 26.4 vs. 27.4 kg/m²), and lower LSMI (mean 43 vs. 56 cm²/m²) than subjects without sarcopenia (all P < 0.05). On multivariate analysis, higher BMI (odd ratio [OR] = 0.599, P = 0.001) was independently associated with a reduced risk of sarcopenia, whereas higher ASCVD risk scores (OR = 1.045, P < 0.001) were independently associated with an increased risk of sarcopenia. Sarcopenia is significantly associated with lower BMI and higher cardiovascular risk in an obese Asian population.

Relation of body fat mass and fat-free mass to total mortality: results from 7 prospective cohort studies

BACKGROUND

Fat mass and fat-free mass may play independent roles in mortality risk but available studies on body composition have yielded inconsistent results.

OBJECTIVE

The aim was to determine the relations of body fat mass and fat-free mass to risk of mortality.

METHODS

In pooled data from 7 prospective cohorts encompassing 16,155 individuals aged 20 to 93 y (median, 44 y), we used Cox regression and restricted cubic splines to estimate HRs and 95% CIs for the relation of body composition, measured by bioelectrical impedance analysis, to total mortality. We adjusted for age, study, sex, ethnicity, history of diabetes mellitus, education, smoking, physical activity, and alcohol consumption.

RESULTS

During a median follow-up period of 14 y (range, 3-21 y), 1347 deaths were identified. After mutual adjustment for fat mass and fat-free mass, fat mass showed a J-shaped association with mortality (overall P value < 0.001; P for nonlinearity = 0.003). Using a fat mass index of 7.3 kg/m2 as the reference, a high fat mass index of 13.0 kg/m2 was associated with an HR of 1.56 (95% CI: 1.30, 1.87). In contrast, fat-free mass showed an inverse association with mortality (overall P value < 0.001; P for nonlinearity = 0.001). Compared with a low fat-free mass index of 16.1 kg/m2, a high fat-free mass of 21.9 kg/m2 was associated with an HR of 0.70 (95% CI: 0.56, 0.87).

CONCLUSIONS

Fat mass and fat-free mass show opposing associations with mortality. Excess fat mass is related to increased mortality risk, whereas fat-free mass protects against risk of mortality. These findings suggest that body composition provides important prognostic information on an individual's mortality risk not provided by traditional proxies of adiposity such as BMI.

Effect of Sarcopenia and Body Shape on Cardiovascular Disease According to Obesity Phenotypes

Background

This study aimed to assess the effects of sarcopenia and A Body Shape Index (ABSI) on cardiovascular disease (CVD) risk according to obesity phenotypes.

Methods

We used data from the National Health and Nutrition Examination Survey 1999 to 2012. A total of 25,270 adults were included and classified into the following groups: metabolically healthy normal weight (MHNW), metabolically healthy overweight/obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight/obese (MUO). Sarcopenia was defined as the appendicular skeletal mass index <7 kg/m2 in men and <5.5kg/m2 in women. A multivariate logistic regression analysis was performed to evaluate the odds ratio (OR) of sarcopenia and ABSI for CVD events according to the obesity phenotype.

Results

The MHNW participants with sarcopenia had higher risk for CVD than those without sarcopenia (OR, 2.69; 95% confidence interval [CI], 1.56 to 4.64). In the analysis with MHNW participants without sarcopenia as a reference, the participants with sarcopenia showed a higher OR for CVD than those without sarcopenia in both MHO (OR in participants without sarcopenia, 3.31; 95% CI, 1.94 to 5.64) (OR in participants with sarcopenia, 8.59; 95% CI, 2.63 to 28.04) and MUO participants (OR in participants without sarcopenia, 5.11; 95% CI, 3.21 to 8.15) (OR in participants with sarcopenia, 8.12; 95% CI, 4.04 to 16.32). Participants within the second and third tertiles of ABSI had higher ORs for CVDs than the counterpart of obesity phenotypes within the first tertile.

Conclusion

These results suggest that clinical approaches that consider muscle and body shape are required.

Rapid Progression of Aortic Calcification in Older Men with Low Appendicular Lean Mass and Poor Physical Function

OBJECTIVES

Assessment of the progression of abdominal aortic calcification (AAC) may be a surrogate marker of the impact of physical function on cardiovascular risk. Our aim was to assess the risk of rapid AAC progression in older men with low relative appendicular lean mass (RALM) and poor physical function.

DESIGN

Prospective cohort study.

SETTING

Community-dwelling older men.

PARTICIPANTS

621 men aged 50-85 followed prospectively (baseline, 3 and 7.5 years).

MEASUREMENTS

Body composition was assessed by DXA. Poor physical function was defined as incapacity to perform ≥1 of 5 clinical tests (balance, muscle strength). AAC was assessed using Kauppila's semiquantitative score. Reclassification improvement was assessed by comparing the areas under the curve (AUC) using DeLong's method.

RESULTS

Rapid AAC progression (>0.6 point/year) was found in 168 men (27.1%). After adjustment for confounders including baseline AAC, the risk of rapid AAC progression increased with lower RALM (OR=1.42/SD, 95%CI: 1.09-1.86, p<0.01) and was higher in the lowest (<7.5kg/m2) vs. highest (>8.6kg/m2) quartile (OR=2.15, 95%CI: 1.17-3.95, p<0.01). Poor physical performance was associated with rapid AAC progression (OR=2.76, 95%CI: 1.48-5.91, p<0.005). Low RALM (<7.84kg/m2 defined using Youden's index) and poor physical function contributed to the risk of rapid AAC progression jointly. Men who had low RALM and poor physical function had higher risk of rapid AAC progression vs. men without these traits (OR=4.66, 95%CI: 1.72-12.62, p<0.05). RALM and physical function improved the identification of men with rapid AAC progression (DAUC=0.026, 95%CI: 0.005-0.046, p<0.05) after adjustment for confounders including baseline AAC score.

CONCLUSIONS

Low RALM and poor physical function are associated with higher risk of rapid AAC progression and possibly represent another measure of cardiovascular risk.

Impact of sarcopenia on glycemic control and atherosclerosis in Japanese patients with type 2 diabetes: Cross-sectional study using outpatient clinical data

AIM

This study examined the association among sarcopenia and various surrogate markers of atherosclerosis in Japanese patients with type 2 diabetes (T2D).

METHODS

Patients with T2D who visited the outpatient clinic comprised the study's participants. Handgrip strength (Grip), usual gait speed (GS) and skeletal muscle index, in addition to glycated hemoglobin, ankle-brachial index (ABI) and intima-media thickening (IMT), were measured in 1030 patients for the diagnosis of sarcopenia. From these results were obtained three categorical data (without sarcopenia [NS], sarcopenia with two factors [Sw2], sarcopenia with three factors [Sw3]), and continuous data for atherosclerosis.

RESULTS

Glycated hemoglobin was significantly high among patients in the Sw3 category, as well as among all patients with sarcopenia, compared with those in the NS group, after adjustment was made for age, gender, duration of diabetes, and medications for hypertension and dyslipidemia. ABI was significantly low among the Sw2 and Sw3 patients, as well as among all patients with sarcopenia, but mean and maximum IMT were not when compared with the NS category of patients after the adjustment described above. However, skeletal muscle index, Grip and GS were positively associated with ABI after the adjustment. Grip and GS were negatively associated with maximum IMT after the adjustment.

CONCLUSIONS

These results imply that measurements to diagnose sarcopenia could play an important role for early detection of preclinical atherosclerosis, specifically peripheral artery disease, among Japanese patients with T2D. Geriatr Gerontol Int 2020; 20: 1196-1201.

Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies

OBJECTIVE

To quantify the association of indices of central obesity, including waist circumference, hip circumference, thigh circumference, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, body adiposity index, and A body shape index, with the risk of all cause mortality in the general population, and to clarify the shape of the dose-response relations.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed and Scopus from inception to July 2019, and the reference lists of all related articles and reviews.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Prospective cohort studies reporting the risk estimates of all cause mortality across at least three categories of indices of central fatness. Studies that reported continuous estimation of the associations were also included.

DATA SYNTHESIS

A random effects dose-response meta-analysis was conducted to assess linear trend estimations. A one stage linear mixed effects meta-analysis was used for estimating dose-response curves.

RESULTS

Of 98 745 studies screened, 1950 full texts were fully reviewed for eligibility. The final analyses consisted of 72 prospective cohort studies with 2 528 297 participants. The summary hazard ratios were as follows: waist circumference (10 cm, 3.94 inch increase): 1.11 (95% confidence interval 1.08 to 1.13, I2=88%, n=50); hip circumference (10 cm, 3.94 inch increase): 0.90 (0.81 to 0.99, I2=95%, n=9); thigh circumference (5 cm, 1.97 inch increase): 0.82 (0.75 to 0.89, I2=54%, n=3); waist-to-hip ratio (0.1 unit increase): 1.20 (1.15 to 1.25, I2=90%, n=31); waist-to-height ratio (0.1 unit increase): 1.24 (1.12 to 1.36, I2=94%, n=11); waist-to-thigh ratio (0.1 unit increase): 1.21 (1.03 to 1.39, I2=97%, n=2); body adiposity index (10% increase): 1.17 (1.00 to 1.33, I2=75%, n=4); and A body shape index (0.005 unit increase): 1.15 (1.10 to 1.20, I2=87%, n=9). Positive associations persisted after accounting for body mass index. A nearly J shaped association was found between waist circumference and waist-to-height ratio and the risk of all cause mortality in men and women. A positive monotonic association was observed for waist-to-hip ratio and A body shape index. The association was U shaped for body adiposity index.

CONCLUSIONS

Indices of central fatness including waist circumference, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, body adiposity index, and A body shape index, independent of overall adiposity, were positively and significantly associated with a higher all cause mortality risk. Larger hip circumference and thigh circumference were associated with a lower risk. The results suggest that measures of central adiposity could be used with body mass index as a supplementary approach to determine the risk of premature death.

Effect of body shape on the development of cardiovascular disease in individuals with metabolically healthy obesity

Studies about the effects of metabolically healthy obesity on cardiovascular disease (CVD) have yielded conflicting results. These heterogeneous results could be due to the limited usefulness of BMI in measuring general adiposity, as body mass index (BMI) does not accurately reflect body composition. This study aimed to evaluate the effect of body shape on CVD outcomes across different obesity phenotypes, and to provide an explanation for the heterogeneous effects of metabolically healthy obese (MHO) phenotype on CVD.We analyzed data from the Korean Genome and Epidemiology Study, a population-based cohort study conducted between 2001 and 2012. We divided the participants into 4 groups: metabolically healthy non-obese (MHNO), MHO, metabolically unhealthy non-obese (MUNO), and metabolically unhealthy obese (MUO). To assess body shape, we calculated the z-score of the log-transformed a body shape index (LBSIZ). We computed Pearson correlation coefficients to examine the association of LBSIZ with muscle mass index, percentage of total fat mass (%Total FM), and percentage of abdominal fat mass (%Abdominal FM). We also used Cox proportional hazards regression to evaluate the effect of LBSIZ on CVD events according to the obesity phenotypes.A total of 9460 participants were assessed in this study. The incidence of CVD was 8.53 cases per 1000 person-year. LBSIZ showed strong positive correlation with %Total FM and %Abdominal FM, but negative correlation with muscle mass index. In Cox regression, MHO individuals did not show increased risk of CVD compared with MHNO individuals (hazard ratio [HR], 1.29; 95% confidence interval [CI], 0.96-1.73). However, MHO individuals in the 3rd (HR, 2.40; 95% CI, 1.28-4.51) and 4th (HR, 3.67; 95% CI, 1.99-6.74) quarters of LBSIZ showed significantly higher risk of CVD compared with MHNO individuals in the 1st quarter of LBSIZ. Moreover, LBSIZ showed a linear relationship with CVD among MHO individuals.While the MHO individuals showed similar CVD risk to the MHNO individuals, CVD risk increases with LBSIZ among the MHO individuals. LBSIZ appears to be a useful measure for CVD risk assessment in clinical practice and epidemiologic studies, especially for MHO patients.

Significance of body mass index for diagnosing sarcopenia is equivalent to slow gait speed in Japanese individuals with type 2 diabetes: Cross-sectional study using outpatient clinical data

Aims/Introduction

This study examined the association between body mass index (BMI) and the risk of sarcopenia in Japanese type 2 diabetes patients.

Materials and Methods

Patients with type 2 diabetes who visited an outpatient clinic comprised the study’s participants. Sarcopenia was defined using the definition of the Asian Working Group for Sarcopenia 2014. The area under the curve was examined for the presence of sarcopenia based on the receiver operating characteristic curve of BMI.

Results

Among 1,137 patients, 210 were diagnosed with low grip strength, 78 with slow gait speed, 444 with low muscle mass and 142 with sarcopenia. The optimal cut‐off point of BMI level for risk of sarcopenia was 24.4 kg/m² (area under the curve 0.729, 95% confidence interval 0.688–0.770, sensitivity 0.587, specificity 0.789). Furthermore, the receiver operating characteristic curve of BMI for sarcopenia did not significantly differ (P = 0.09) from that of gait speed, an established marker of sarcopenia. In both the male and female groups, there was no difference between the receiver operating characteristic curves of BMI and gait speed for sarcopenia. (P = 0.23 and P = 0.40, respectively).

Conclusions

These results suggest that a BMI <24 kg/m² among Japanese patients with type 2 diabetes could increase their risk of sarcopenia, the extent of which is equivalent to the risk for sarcopenia from slow gait speed in this study. Further prospective investigation, however, is required.

Pectoralis muscle area is associated with bone mineral density and lung function in lung transplant candidates

Loss of bone mineral density and skeletal muscle area are linked in lung transplant patients. This loss is greater in patients with restrictive compared with obstructive lung diseases.

INTRODUCTION

Sarcopenia and osteoporosis are associated with aging and chronic illnesses and may be linked in patients with advanced lung disease. Pectoralis muscle index (PMI) quantitated on computed tomography (CT) of the chest can be used to measure skeletal muscle mass. This study aimed to determine the relationship of PMI to clinical parameters including bone mineral density (BMD) in candidates for lung transplantation.

METHODS

A retrospective review of transplant candidates at a single center was performed. Demographic, anthropomorphic, and clinical data were recorded. Pectoralis muscle area (PMA) was determined on an axial slice from a chest CT. PMI was calculated as the PMA divided by height squared. BMD was obtained from routine dual-energy X-ray absorptiometry (DXA) scan.

RESULTS

In 226 included patients, mean PMI was 8.2 ± 3.0 cm²/m² in males and 6.1 ± 2.1 cm²/m² in females. Osteopenia was present in 44.4%, and 23.2% of patients had osteoporosis. Patients with obstructive lung disease had lower body mass index (22.0 ± 4.9 versus 27.9 ± 4.9 kg/m², p < 0.001), PMI (6.0 ± 2.3 versus 8.2 ± 2.8 cm²/m², p < 0.001), and BMD (- 2.3 ± 1.1 versus - 1.3 ± 1.1, p < 0.001) compared with patients with restrictive lung disease. PMI was a significant predictor of BMD (β = 0.16, p < 0.001).

CONCLUSION

The association between muscle area and BMD in lung transplant candidates suggests that similar mechanisms may underlie the development of both. Differences in PMI and BMD in patients with obstructive versus restrictive lung disease may result from differences in respiratory physiology or disease processes.

Sarcopenic obesity in ageing: cardiovascular outcomes and mortality

Obesity is a major public health issue with prevalence increasing worldwide. Obesity is a well-established risk factor for CVD and mortality in adult populations. However, the impact of being overweight or obese in the elderly on CVD and mortality is controversial. Some studies even suggest that overweight and obesity, measured by BMI, are apparently associated with a decreased mortality risk (known as the obesity paradox). Ageing is associated with an increase in visceral fat and a progressive loss of muscle mass. Fat mass is positively associated and lean mass is negatively associated with risk of mortality. Therefore, in older adults BMI is not a good indicator of obesity. Sarcopenia has been defined as the degenerative loss of muscle mass, quality and strength with age and is of major concern in ageing populations. Sarcopenia has previously been associated with increased risks of metabolic impairment, cardiovascular risk factors, physical disability and mortality. It is possible for sarcopenia to co-exist with obesity, and sarcopenic obesity is a new class of obesity in older adults who have high adiposity levels together with low muscle mass, quality or strength. Therefore, sarcopenia with obesity may act together to increase their effect on metabolic disorders, CVD and mortality. This review will discuss the available evidence for the health implications of sarcopenic obesity on CVD and mortality in older adults.

Multiple measures derived from 3D photonic body scans improve predictions of fat and muscle mass in young Swiss men

INTRODUCTION

Digital tools like 3D laser-based photonic scanners, which can assess external anthropometric measurements for population based studies, and predict body composition, are gaining in importance. Here we focus on a) systematic deviation between manually determined and scanned standard measurements, b) differences regarding the strength of association between these standard measurements and body composition, and c) improving these predictions of body composition by considering additional scan measurements.

METHODS

We analysed 104 men aged 19-23. Bioelectrical Impedance Analysis was used to estimate whole body fat mass, visceral fat mass and skeletal muscle mass (SMM). For the 3D body scans, an Anthroscan VITUSbodyscan was used to automatically obtain 90 body shape measurements. Manual anthropometric measurements (height, weight, waist circumference) were also taken.

RESULTS

Scanned and manually measured height, waist circumference, waist-to-height-ratio, and BMI were strongly correlated (Spearman Rho>0.96), however we also found systematic differences. When these variables were used to predict body fat or muscle mass, explained variation and prediction standard errors were similar between scanned and manual measurements. The univariable predictions performed well for both visceral fat (r2 up to 0.92) and absolute fat mass (AFM, r2 up to 0.87) but not for SMM (r2 up to 0.54). Of the 90 body scanner measures used in the multivariable prediction models, belly circumference and middle hip circumference were the most important predictors of body fat content. Stepwise forward model selection using the AIC criterion showed that the best predictive power (r2 up to 0.99) was achieved with models including 49 scanner measurements.

CONCLUSION

The use of a 3D full body scanner produced results that strongly correlate to manually measured anthropometric measures. Predictions were improved substantially by including multiple measurements, which can only be obtained with a 3D body scanner, in the models.

Expression of MuRF1 or MuRF2 is essential for the induction of skeletal muscle atrophy and dysfunction in a murine pulmonary hypertension model

BACKGROUND

Pulmonary hypertension leads to right ventricular heart failure and ultimately to cardiac cachexia. Cardiac cachexia induces skeletal muscles atrophy and contractile dysfunction. MAFbx and MuRF1 are two key proteins that have been implicated in chronic muscle atrophy of several wasting states.

METHODS

Monocrotaline (MCT) was injected over eight weeks into mice to establish pulmonary hypertension as a murine model for cardiac cachexia. The effects on skeletal muscle atrophy, myofiber force, and selected muscle proteins were evaluated in wild-type (WT), MuRF1, and MuRF2-KO mice by determining muscle weights, in vitro muscle force and enzyme activities in soleus and tibialis anterior (TA) muscle.

RESULTS

In WT, MCT treatment induced wasting of soleus and TA mass, loss of myofiber force, and depletion of citrate synthase (CS), creatine kinase (CK), and malate dehydrogenase (MDH) (all key metabolic enzymes). This suggests that the murine MCT model is useful to mimic peripheral myopathies as found in human cardiac cachexia. In MuRF1 and MuRF2-KO mice, soleus and TA muscles were protected from atrophy, contractile dysfunction, while metabolic enzymes were not lowered in MuRF1 or MuRF2-KO mice. Furthermore, MuRF2 expression was lower in MuRF1KO mice when compared to C57BL/6 mice.

CONCLUSIONS

In addition to MuRF1, inactivation of MuRF2 also provides a potent protection from peripheral myopathy in cardiac cachexia. The protection of metabolic enzymes in both MuRF1KO and MuRF2KO mice as well as the dependence of MuRF2 expression on MuRF1 suggests intimate relationships between MuRF1 and MuRF2 during muscle atrophy signaling.

Phenotypes of Sarcopenic Obesity: Exploring the Effects on Peri-Muscular Fat, the Obesity Paradox, Hormone-Related Responses and the Clinical Implications

Sarcopenic obesity combines the words sarcopenia and obesity. This definition of obesity should be better differentiated between visceral and subcutaneous fat phenotypes. For this reason, this review lays the foundation for defining the subcutaneous and the visceral fat into the context of sarcopenia. Thus, the review aims to explore the missing links on pathogenesis of visceral fat and its relationship on age: defining the peri-muscular fat as a new entity and the subcutaneous fat as a first factor that leads to the obesity paradox. Last but not least, this review underlines and motivates the mechanisms of the hormonal responses and anti-inflammatory adipokines responsible for the clinical implications of sarcopenic visceral obesity, describing factor by factor the multiple axis between the visceral fat-sarcopenia and all mortality outcomes linked to cancer, diabetes, cardiovascular diseases, cirrhosis, polycystic ovary, disability and postoperative complications.

Health Consequences of Sarcopenic Obesity: A Narrative Review

Sarcopenia is defined as the age-related loss of muscle mass and strength or physical performance. Increased amounts of adipose tissue often accompany sarcopenia, a condition referred to as sarcopenic obesity. The prevalence of sarcopenic obesity among adults is rapidly increasing worldwide. However, the lack of a universal definition of sarcopenia limits comparisons between studies. Sarcopenia and obesity have similar pathophysiologic factors, including lifestyle behaviors, hormones, and immunological factors, all of which may synergistically affect the risk of developing a series of adverse health issues. Increasing evidence has shown that sarcopenic obesity is associated with accelerated functional decline and increased risks of cardiometabolic diseases and mortality. Therefore, the identification of sarcopenic obesity may be critical for clinicians in aging societies. In this review, we discuss the effect of sarcopenic obesity on multiple health outcomes and its role as a predictor of these outcomes based on the components of sarcopenia, including muscle mass, muscle strength, and physical performance.

Small-molecule-mediated chemical knock-down of MuRF1/MuRF2 and attenuation of diaphragm dysfunction in chronic heart failure

BACKGROUND

Chronic heart failure (CHF) leads to diaphragm myopathy that significantly impairs quality of life and worsens prognosis. In this study, we aimed to assess the efficacy of a recently discovered small-molecule inhibitor of MuRF1 in treating CHF-induced diaphragm myopathy and loss of contractile function.

METHODS

Myocardial infarction was induced in mice by ligation of the left anterior descending coronary artery. Sham-operated animals (sham) served as controls. One week post-left anterior descending coronary artery ligation animals were randomized into two groups-one group was fed control rodent chow, whereas the other group was fed a diet containing 0.1% of the compound ID#704946-a recently described MuRF1-interfering small molecule. Echocardiography confirmed development of CHF after 10 weeks. Functional and molecular analysis of the diaphragm was subsequently performed.

RESULTS

Chronic heart failure induced diaphragm fibre atrophy and contractile dysfunction by ~20%, as well as decreased activity of enzymes involved in mitochondrial energy production (P < 0.05). Treatment with compound ID#704946 in CHF mice had beneficial effects on the diaphragm: contractile function was protected, while mitochondrial enzyme activity and up-regulation of the MuRF1 and MuRF2 was attenuated after infarct.

CONCLUSIONS

Our murine CHF model presented with diaphragm fibre atrophy, impaired contractile function, and reduced mitochondrial enzyme activities. Compound ID#704946 rescued from this partially, possibly by targeting MuRF1/MuRF2. However, at this stage of our study, we refrain to claim specific mechanism(s) and targets of compound ID#704946, because the nature of changes after 12 weeks of feeding is likely to be complex and is not necessarily caused by direct mechanistic effects.

Effects of PM2.5 on Skeletal Muscle Mass and Body Fat Mass of the Elderly in Taipei, Taiwan

Loss of skeletal muscle mass is common with aging and can cause morbidity and mortality in the elderly. The effects of particulate air pollution on skeletal muscle mass is not known. The study aims to assess the chronic effects of ambient fine particulates (PM_2.5) on the body composition of the elderly. From October 2015 to November 2016, a cross-sectional survey on 530 elderly (age > = 65 years) was conducted in the Taipei Basin, Taiwan. The body composition was measured by bioelectrical impedance analysis (InBody 120). One year exposure to air pollution was estimated using the Kriging method at the participant’s residence. Multiple linear regression analysis, after adjustments for demographics and co-pollutants, was used to examine the effects of PM_2.5 on body composition indices and force of handgrip. Changes in body composition for an interquartile (1.4 μm/m³) increase in PM_2.5 concentration included a 0.4 kg (95% confidence interval (CI): −0.31, −0.58; p < 0.0001) decrease in skeletal muscle mass (2.0%) and a 0.7 kg (95% CI: 0.47, 0.91; p < 0.0001) increase in body fat mass (3.6%). While PM_2.5 reduced fat free mass in the upper extremities and trunk, but not in the lower extremities, it increased body fat mass in the three parts. There was no significant effect of PM_2.5 on handgrip force. Higher physical activity (versus lower than median) was associated with less detrimental effect of PM_2.5 on skeletal muscle mass and body fat mass (p values for interaction term: 0.009 and 0.013, respectively). Long-term PM_2.5 exposure is associated with decreased skeletal muscle mass and increased body fat mass in the elderly, which can be ameliorated by physical activity.