Sarcopenia, dynapenia, and the impact of advancing age on human skeletal muscle size and strength; a quantitative review

Prevalence and factors associated with sarcopenia among older adults in a post-acute hospital in Singapore

BACKGROUND

Sarcopenia is common in older adults worldwide, but its prevalence varies widely owing to differences in diagnostic criteria, population sampled, and care setting. We aimed to determine the prevalence and factors associated with sarcopenia in patients aged 65 and above admitted to a post-acute hospital in Singapore.

METHODS

This was a cross-sectional study of 400 patients recruited from a community hospital in Singapore. Data including socio-demographics, physical activity, nutritional status, cognition, clinical and functional status, as well as anthropometric measurements were collected. Sarcopenia was defined using the Asian Working Group for Sarcopenia 2019 criteria [AWGS2019].

RESULTS

Of the 383 patients with complete datasets, overall prevalence of sarcopenia was 54% while prevalence of severe sarcopenia was 38.9%. Participants with increased age, male gender and a low physical activity level were more likely to be sarcopenic, while those with higher hip circumference and higher BMI of ≥27.5m/kg2 were less likely to be sarcopenic. Other than the above-mentioned variables, cognitive impairment was also associated with severe sarcopenia.

CONCLUSIONS

More than 1 in 2 older adults admitted to a post-acute hospital in Singapore are sarcopenic. There is an urgent need to address this important clinical syndrome burden and to identify patients at risk of sarcopenia in post-acute settings in Singapore for early intervention.

Prospective associations between changes in physical activity and sedentary time and subsequent lean muscle mass in older English adults: the EPIC-Norfolk cohort study

BACKGROUND

The longitudinal associations between physical behaviours and lean muscle mass indices need to be better understood to aid healthy ageing intervention development.

METHODS

We assessed physical behaviours (total physical activity, moderate-to-vigorous physical activity (MVPA), light physical activity, total sedentary time and prolonged sedentary bout time) for 7 days using hip-worn accelerometers. We also assessed domain-specific physical behaviours (walking, cycling, gardening and housework time) with self-report questionnaires at baseline (2006-2011) and follow-up (2012-2016) in the European Prospective Investigation into Cancer (EPIC)-Norfolk study. We assessed body composition using dual-energy X-ray absorptiometry (DEXA) at follow-up in 1535 participants (≥ 60 years at baseline). From this, we derived appendicular lean muscle mass (ALM) indices (% relative ALM = (ALM/total body weight)*100), body mass index (BMI)-scaled ALM (ALM/BMI, kg/kg/m2) and height-scaled ALM (ALM/height2, kg/m2)). We evaluated the prospective associations of both baseline and change in physical behaviours with follow-up muscle mass indices using multivariable linear regression.

RESULTS

Over 5.5 years (SD 14.8) follow-up, higher baseline accelerometer-measured physical activity and lower sedentary time were associated with higher subsequent relative ALM and BMI-scaled ALM, but not height-scaled ALM (e.g. 0.02% higher subsequent relative ALM per minute/day of baseline MVPA for men). Greater increases in physical activity and greater declines in sedentary time variables were associated with higher subsequent relative ALM and BMI-scaled ALM, but not height-scaled ALM (e.g. 0.001 kg/kg/m2 subsequent BMI-scaled ALM and 0.04% subsequent relative ALM per min/day/year increases in LPA over follow-up; 0.001 kg/kg/m2 subsequent BMI-scaled ALM and -0.03% subsequent relative ALM per min/day/year less of total sedentary time over follow-up). Greater increases in women's cycling and gardening over follow-up were associated with greater subsequent relative ALM (cycling 0.9% per hour/week/year; gardening 0.2% per hour/week/year) and BMI-scaled ALM (cycling 0.03 kg/kg/m2 per hour/week/year; gardening 0.004 kg/kg/m2 per hour/week/year).

CONCLUSION

Physical behaviours across all intensities, and in women more specifically cycling and gardening, may help prevent age-related declines in muscle mass.

Differences in Functional Capacity between Oncologic and Non-Oncologic Populations: Reference Values

This study is focused on the fact that in the context of increasing global aging and cancer diagnoses, additional challenges arise in clinical care. Adequate functionality and body composition are key to coping with antineoplastic treatment, which can lead to better treatment tolerance, survival, and quality of life. This is a cross-sectional comparative study focused on the assessment and comparison of body composition and functionality between cancer patients and a reference population, with the aim of establishing meaningful baseline values. Techniques such as manual dynamometry, the Five-Times Sit-to-Stand test, and bioimpedance were used to collect data from 374 oncologic patients and 1244 reference individuals. The results reveal significant disparities in functionality and body composition among participants, and provide age group-specific adjusted baseline values for those diagnosed with cancer. These findings may have crucial clinical implications for applying particular cut-off points designed for this population group, which makes the assessment process faster and more accurate, enhances the capacity of medical personnel to act quickly, and improves the management of frailty in cancer patients.

Uric acid formation is driven by crosstalk between skeletal muscle and other cell types

Hyperuricemia is implicated in numerous pathologies, but the mechanisms underlying uric acid production are poorly understood. Using a combination of mouse studies, cell culture studies, and human serum samples, we sought to determine the cellular source of uric acid. In mice, fasting and glucocorticoid treatment increased serum uric acid and uric acid release from ex vivo-incubated skeletal muscle. In vitro, glucocorticoids and the transcription factor FoxO3 increased purine nucleotide degradation and purine release from differentiated muscle cells, which coincided with the transcriptional upregulation of AMP deaminase 3, a rate-limiting enzyme in adenine nucleotide degradation. Heavy isotope tracing during coculture experiments revealed that oxidation of muscle purines to uric acid required their transfer from muscle cells to a cell type that expresses xanthine oxidoreductase, such as endothelial cells. Last, in healthy women, matched for age and body composition, serum uric acid was greater in individuals scoring below average on standard physical function assessments. Together, these studies reveal skeletal muscle purine degradation is an underlying driver of uric acid production, with the final step of uric acid production occurring primarily in a nonmuscle cell type. This suggests that skeletal muscle fiber purine degradation may represent a therapeutic target to reduce serum uric acid and treat numerous pathologies.

Dietary intake of micronized avian eggshell membrane in aged mice reduces circulating inflammatory markers, increases microbiota diversity, and attenuates skeletal muscle aging

Introduction

Avian eggshell membrane (ESM) is a complex extracellular matrix comprising collagens, glycoproteins, proteoglycans, and hyaluronic acid. We have previously demonstrated that ESM possesses anti-inflammatory properties in vitro and regulates wound healing processes in vivo. The present study aimed to investigate if oral intake of micronized ESM could attenuate skeletal muscle aging associated with beneficial alterations in gut microbiota profile and reduced inflammation.

Methods

Elderly male C57BL/6 mice were fed an AIN93G diet supplemented with 0, 0.1, 1, or 8% ESM. Young mice were used as reference. The digestibility of ESM was investigated using the static in vitro digestion model INFOGEST for older people and adults, and the gut microbiota profile was analyzed in mice. In addition, we performed a small-scale pre-clinical human study with healthy home-dwelling elderly (>70 years) who received capsules with a placebo or 500 mg ESM every day for 4 weeks and studied the effect on circulating inflammatory markers.

Results and discussion

Intake of ESM in elderly mice impacted and attenuated several well-known hallmarks of aging, such as a reduction in the number of skeletal muscle fibers, the appearance of centronucleated fibers, a decrease in type IIa/IIx fiber type proportion, reduced gene expression of satellite cell markers Sdc3 and Pax7 and increased gene expression of the muscle atrophy marker Fbxo32. Similarly, a transition toward the phenotypic characteristics of young mice was observed for several proteins involved in cellular processes and metabolism. The digestibility of ESM was poor, especially for the elderly condition. Furthermore, our experiments showed that mice fed with 8% ESM had increased gut microbiota diversity and altered microbiota composition compared with the other groups. ESM in the diet also lowered the expression of the inflammation marker TNFA in mice and in vitro in THP-1 macrophages. In the human study, intake of ESM capsules significantly reduced the inflammatory marker CRP. Altogether, our results suggest that ESM, a natural extracellular biomaterial, may be attractive as a nutraceutical candidate with a possible effect on skeletal muscle aging possibly through its immunomodulating effect or gut microbiota.

Effect of breakfast protein intake on muscle mass and strength in adults: a scoping review

BACKGROUND

The distribution of protein intake throughout the day is frequently skewed, with breakfast having the lowest protein intake across all age groups. There is no review that addresses the association between breakfast protein intake and muscle mass and strength.

OBJECTIVE

This scoping review aims to summarize the literature on the relationship between protein intake during breakfast and muscle mass and strength in adults.

METHODS

This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. Two independent reviewers screened and appraised the articles identified from 3 electronic databases (Medline, Web of Science, and Scopus) that focused on protein intake per meal and its impact on muscle-related outcomes.

RESULTS

A total of 14 763 articles were retrieved from 3 databases, and after the screening process, 15 articles were included for analysis. Approximately 58.8% of findings from 11 studies examining the association between high protein intake during breakfast and muscle mass indicated an increase in muscle mass among participants. Half of 6 studies (50.0%) exploring the relationship between high protein intake at breakfast and muscle strength demonstrated an increase in muscle strength. Consuming high amounts of protein at breakfast or more protein in the morning than in the evening was associated with an increase in the skeletal muscle index and lean body mass.

CONCLUSION

Protein consumption at breakfast revealed potential benefits in increasing muscle mass across 5 studies involving an elderly population and 2 studies encompassing middle-aged women and young men in our review. However, the relationship between protein intake at breakfast and muscle strength remains unclear. Further high-quality randomized controlled trials are required to examine whether adults can preserve skeletal muscle health outcomes by consuming higher amounts of protein at breakfast.

Risk factors and a model for prognosis prediction after intravenous thrombolysis with alteplase in acute ischemic stroke based on propensity score matching

Background: Alteplase intravenous thrombolysis is effective for treating acute ischemic stroke (AIS) within 4.5 h. Nevertheless, the prognosis remains poor for some patients.Objective: To investigate the risk factors for poor prognosis in patients undergoing intravenous thrombolysis with alteplase following AIS based on propensity score matching and to develop a predictive model.Result: Multivariate logistic regression analysis showed that baseline blood glucose (OR = 1.20, 95%CI, 1.03-1.39), baseline NIH Stroke Scale score (OR = 1.23, 95%CI, 1.12-1.35), and hyperlipidemia (OR = 6.60, 95%CI 1.74-25.00) were risk factors for poor prognosis in patients with AIS undergoing alteplase intravenous thrombolysis. Using these factors, a nomogram model was constructed for predicting patient prognosis at 3 months. The areas under the receiver operating characteristic curve (AUCs) of the training and validation groups were 0.792 (95CI% 0.715-0.870) and 0.885 (95CI% 0.798-0.972), respectively, showing good differentiation. The Hosmer Lemeshow goodness-of-fit test showed that the model had good fit. The calibration curve fitted well with the ideal curve, and the decision curve analysis curve showed that the model had good clinical applicability when the threshold probability was between 10%-80%.Conclusion: The established nomogram could successfully predict the 3-month prognosis of patients with AIS after undergoing alteplase intravenous thrombolysis. The model thus has clinical application value.

Ultrasound for measurement of skeletal muscle mass quantity and muscle composition/architecture in critically ill patients: A scoping review on studies' aims, methods, and findings

AIMS

This scoping review aimed to identify, explore, and map the objectives, methodological aspects, and results of studies that used ultrasound (US) to assess skeletal muscle (SM) in critically ill patients.

METHODS

A scoping review was conducted according to the Joanna Briggs Institute's methodology. All studies that evaluated SM parameters from the US in patients admitted to the intensive care unit (ICU) were considered eligible. We categorized muscle thickness and cross-sectional area as parameters for assessing SM quantity, while echogenicity, fascicle length, and pennation angle analysis were used to evaluate muscle "quality" (composition/architecture). A literature search was conducted using four databases for articles published until December 2022. Independent reviewers selected the studies and extracted data. Descriptive statistics were calculated to present the results.

RESULTS

A total of 107 studies were included, the majority of which were prospective cohort studies (59.8 %) conducted in general ICUs (49.5 %). The most frequent objective of the studies was to evaluate SM quantity depletion during the ICU stay (25.2 %), followed by determining whether a specific intervention would modify SM (21.5 %). Most studies performed serial SM evaluations (76.1 %). The rectus femoris muscle thickness was evaluated in most studies (67.9 %), followed by the rectus femoris cross-sectional area (54.3 %) and the vastus intermedius muscle thickness (40.2 %). The studies demonstrated the feasibility and reproducibility of US for SM evaluation, especially related to quantitative parameters. Most studies (70.3 %) reported significant SM quantity depletion during hospitalization. However, the accuracy of the US in measuring SM varied across the studies.

CONCLUSIONS

The lack of detailed description and standardization in the protocols adopted by the studies included in this scoping review precludes the translation of the evidence related to US for SM assessment into clinical practice.

The roles of sex hormones in the pathophysiology of age-related sarcopenia and frailty

Background

Sarcopenia is an age-related condition characterized by a progressive and systemic decline in skeletal muscle mass, quality, and strength. The incidence of sarcopenia contains sex-specific aspects, indicating the contribution of sex hormones to its pathophysiology. This review focuses on changing trends in sarcopenia, discusses alterations in definitions and diagnostic criteria, and emphasizes the association between sarcopenia and sex hormones.

Methods

A literature search was performed on PubMed for related articles published between 1997 and December 2023 using appropriate keywords.

Main Findings Results

Advances in research have emphasized the significance of muscle quality and strength over muscle mass, resulting in new diagnostic criteria for sarcopenia. Androgens demonstrated anabolic effects on skeletal muscles and played a significant role in the pathophysiology of sarcopenia. In clinical settings, androgen replacement therapy has exhibited certain positive outcomes for treating sarcopenia, despite concerns about potential side effects. Conversely, estrogen is involved in skeletal muscle maintenance, but the detailed mechanisms remain unclear. Moreover, results regarding the clinical application of estrogen replacement therapy for treating sarcopenia remained inconsistent.

Conclusion

The elucidation of molecular mechanisms that involve sex hormones is eagerly awaited for novel therapeutic interventions for sarcopenia.

The relationship between lifestyles and sarcopenia-related traits: A two-sample Mendelian randomization study

OBJECTIVE

To investigate the causal association between lifestyles (smoking, drinking consumption and physical activity) and sarcopenia-related traits by Mendelian randomized analysis.

METHODS

Instrumental variables from the genome-wide association study were used for analysis. The exposure factors were lifestyle factors, including smoking, alcohol consumption, moderate physical activity and vigorous physical activity, and the outcome variables were low hand grip strength and appendicular lean mass. The inverse variance weighted (IVW) method and other MR methods were used for analysis. Heterogeneity test, sensitivity analysis and pleiotropy analysis were performed.

RESULTS

According to a primary causal effects model with MR analyses by the IVW method, smoking was a decreased risk of low hand grip strength (odds ratio (OR) = 0.899, 95% confidence interval (CI) = 0.829-0.974, P = 0.010), while alcohol consumption was a significant correlation with low hand grip strength (OR = 1.137, 95% CI = 1.020-1.267, P = 0.020). There was no significant relationship between smoking, alcohol, and appendicular lean mass. In addition, moderate or vigorous physical showed no significant correlation with low hand grip strength and appendicular lean mass.

CONCLUSION

This study demonstrated that smoking may be causally related to a lower risk of low hand grip strength, while alcohol may increase the risk of low hand grip strength. There was no causal relationship between physical activity and sarcopenia-related traits.

Dynapenic Abdominal Obesity Increases Risk for Falls Among Adults Aged ≥50 Years: A Prospective Analysis of the Irish Longitudinal Study on Ageing

BACKGROUND

There is a scarcity of studies examining the longitudinal relationship between dynapenic abdominal obesity (DAO; ie, impairment in muscle strength and high waist circumference) and future fall risk. Therefore, we aimed to investigate the prospective association between DAO at baseline and falls occurring during 2 years of follow-up in a nationally representative sample of middle-aged and older individuals from Ireland.

METHODS

Data from 2 consecutive waves of the Irish Longitudinal Study on Ageing survey were analyzed. Dynapenia was defined as handgrip strength of <26 kg for men and <16 kg for women. Abdominal obesity was defined as a waist circumference of >88 cm for women and >102 cm for men. DAO was assessed at Wave 1 (2009-2011) and was defined as having both dynapenia and abdominal obesity. Falls occurring between Wave 1 and Wave 2 (2012-2013) were self-reported. Multivariable logistic regression analysis was conducted.

RESULTS

Data on 5 275 individuals aged ≥50 years were analyzed (mean [standard deviation {SD}] age 63.2 [8.9] years; 48.8% males). After adjustment for potential confounders, compared to no dynapenia and no abdominal obesity at baseline, DAO was significantly associated with 1.47 (95% confidence interval [CI]: 1.14-1.89) times higher odds for falls at 2-year follow-up. Dynapenia alone (odds ratio [OR] = 1.08; 95% CI: 0.84-1.40) and abdominal obesity alone (OR = 1.09; 95% CI: 0.91-1.29) were not significantly associated with falls at follow-up.

CONCLUSIONS

DAO increased the risk for falls among middle-aged and older adults in Ireland. Interventions to prevent or reverse DAO may be beneficial for fall reduction.

Preventative and therapeutic potential of tocotrienols on musculoskeletal diseases in ageing

Musculoskeletal health is paramount in an ageing population susceptible to conditions such as osteoporosis, arthritis and fractures. Age-related changes in bone, muscle, and joint function result in declining musculoskeletal health, reduced mobility, increased risk of falls, and persistent discomfort. Preserving musculoskeletal wellbeing is essential for maintaining independence and enhancing the overall quality of life for the elderly. The global burden of musculoskeletal disorders is significant, impacting 1.71 billion individuals worldwide, with age-related muscle atrophy being a well-established phenomenon. Tocotrienols, a unique type of vitamin E found in various sources, demonstrate exceptional antioxidant capabilities compared to tocopherols. This characteristic positions them as promising candidates for addressing musculoskeletal challenges, particularly in mitigating inflammation and oxidative stress underlying musculoskeletal disorders. This review paper comprehensively examines existing research into the preventive and therapeutic potential of tocotrienols in addressing age-related musculoskeletal issues. It sheds light on the promising role of tocotrienols in enhancing musculoskeletal health and overall wellbeing, emphasizing their significance within the broader context of age-related health concerns.

Feasibility of using chest computed tomography (CT) imaging at the first lumbar vertebra (L1) level to assess skeletal muscle mass: a retrospective study

Background

Skeletal muscle mass is an essential parameter for diagnosing sarcopenia. The gold standard for assessing skeletal muscle mass is using computed tomography (CT) to measure skeletal muscle area at the third lumbar vertebra (L3) level. This study aims to investigate whether skeletal muscle mass could be evaluated at the first lumbar vertebra (L1) level using images obtained from routine chest CT scans.

Methods

Skeletal muscle index (SMI, cm2/m2) and skeletal muscle density (SMD, HU) are commonly used to measure relative muscle mass and the degree of fat infiltration. This study used CT images at the L1 level to measure the skeletal muscle area (SMA, cm2) in 815 subjects from the health examination center. Linear regression analysis was used to explore the association between L1 and L3 measurements. The receiver operating characteristic (ROC) analysis was used to assess the predictive performance of L1 SMI for sarcopenia. The sex-specific cut-off values for low skeletal muscle mass in patients under the age of 60 were determined using the following formula: "mean - 1.28 × standard deviation." A multivariate linear regression model was established.

Results

A significantly higher SMI at the L1 level was found in males than in females (43.88 ± 6.33 cm2/m2 vs 33.68 ± 5.03 cm2/m2; P < 0.001). There were strong correlations between measures at the L1 and L3 levels in both the total subject and sex-specific analyses. A negative association was found between age and L3 SMI in males (r = -0.231, P = 0.038). Both body mass index (BMI) and body surface area (BSA) were positively associated with L1 SMI in both males and females. A multivariate analysis was used to establish a prediction rule to predict SMI at the L3 level. The assessment of consistency and interchangeability between predicted and actual SMI at the L3 level yielded moderately good results. Considering the significant differences observed between male and female participants, the sex-specific cut-off values of the L1 SMI for defining low skeletal muscle mass were 36.52 cm2/m2 in males and 27.29 cm2/m2 in females.

Conclusions

Based on a population from central China, the correlated indicators obtained at the L1 level from routine chest CT scans may serve as effective surrogate markers for those at the L3 level in assessing overall skeletal muscle mass.

Frailty in Traumatic Brain Injury-The Significance of Temporal Muscle Thickness

BACKGROUND

Temporal muscle thickness (TMT) on cranial CT scans has recently been identified as a prognostic imaging parameter for assessing a patient's baseline frailty. Here, we analyzed whether TMT correlates with Traumatic brain injury (TBI) severity and whether it can be used to predict outcome(s) after TBI.

METHODS

We analyzed the radiological and clinical data sets of 193 patients with TBI who were admitted to our institution and correlated the radiological data with clinical outcomes after stratification for TMT.

RESULTS

Our analyses showed a significant association between high TMT and increased risk for intracranial hemorrhage (p = 0.0135) but improved mRS at 6 months (p = 0.001) as compared to patients with low TMT. Congruent with such findings, a lower TMT was associated with falls and reduced outcomes at 6 months (p < 0.0001 and p < 0.0001).

CONCLUSION

High TMT was robustly associated with head trauma sequelae but was also associated with good clinical outcomes in TBI patients. These findings consolidate the significance of TMT as an objective marker of frailty in TBI patients; such measurements may ultimately be leveraged as prognostic indicators.

Associations between PBMC whole genome transcriptome, muscle strength, muscle mass, and physical performance in healthy home-dwelling older women

Increasing age is accompanied by many changes, including declining functional skeletal muscle health and immune dysfunction. Peripheral blood mononuclear cells (PBMCs) are circulating cells that assemble an immune response, but their whole genome transcriptome has not been studied in the context of age-related muscle health. Consequently, this article explored associations between three muscle variables indicative of functional muscle health - maximum handgrip strength (muscle strength), appendicular skeletal muscle mass index (ASMI, muscle mass), and gait speed (physical performance) - and two groups of bioinformatics-generated PBMC gene expression features (gene expression-estimated leukocyte subset proportions and gene clusters). We analyzed cross-sectional data from 95 home-dwelling healthy women ≥ 70 years, using "cell-type identification by estimating relative subsets of RNA transcripts" (CIBERSORT) to estimate leukocyte subset proportions and "weighted correlation network analysis" (WGCNA) to generate gene clusters. Associations were studied using linear regression models and relevant gene clusters were subjected to gene set enrichment analysis using gene ontology. Gait speed and ASMI associated with CIBERSORT-estimated monocyte proportions (β =  - 0.090, 95% CI = (- 0.146, - 0.034), p-value = 0.002 for gait speed, and β =  - 0.206, 95% CI = (- 0.385, - 0.028), p-value = 0.024 for ASMI), and gait speed associated with CIBERSORT-estimated M2 macrophage proportions (β =  - 0.026, 95% CI = (- 0.043, - 0.008), p-value = 0.004). Furthermore, maximum handgrip strength associated with nine WGCNA gene clusters, enriched in processes related to immune function and skeletal muscle cells (β in the range - 0.007 to 0.008, p-values < 0.05). These results illustrate interactions between skeletal muscle and the immune system, supporting the notion that age-related functional muscle health and the immune system are closely linked.

Hallmarks of ageing in human skeletal muscle and implications for understanding the pathophysiology of sarcopenia in women and men

Ageing is a complex biological process associated with increased morbidity and mortality. Nine classic, interdependent hallmarks of ageing have been proposed involving genetic and biochemical pathways that collectively influence ageing trajectories and susceptibility to pathology in humans. Ageing skeletal muscle undergoes profound morphological and physiological changes associated with loss of strength, mass, and function, a condition known as sarcopenia. The aetiology of sarcopenia is complex and whilst research in this area is growing rapidly, there is a relative paucity of human studies, particularly in older women. Here, we evaluate how the nine classic hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication contribute to skeletal muscle ageing and the pathophysiology of sarcopenia. We also highlight five novel hallmarks of particular significance to skeletal muscle ageing: inflammation, neural dysfunction, extracellular matrix dysfunction, reduced vascular perfusion, and ionic dyshomeostasis, and discuss how the classic and novel hallmarks are interconnected. Their clinical relevance and translational potential are also considered.

Long-chain n-3 PUFA ingestion for the stimulation of muscle protein synthesis in healthy older adults

This review aims to critically evaluate the efficacy of long-chain ո-3 PUFA ingestion in modulating muscle protein synthesis (MPS), with application to maintaining skeletal muscle mass, strength and function into later life. Ageing is associated with a gradual decline in muscle mass, specifically atrophy of type II fibres, that is exacerbated by periods of (in)voluntary muscle disuse. At the metabolic level, in otherwise healthy older adults, muscle atrophy is underpinned by anabolic resistance which describes the impaired MPS response to non-pharmacological anabolic stimuli, namely, physical activity/exercise and amino acid provision. Accumulating evidence implicates a mechanistic role for n-3 PUFA in upregulating MPS under stimulated conditions (post-prandial state or following exercise) via incorporation of EPA and DHA into the skeletal muscle phospholipid membrane. In some instances, these changes in MPS with chronic ո-3 PUFA ingestion have translated into clinically relevant improvements in muscle mass, strength and function; an observation evidently more prevalent in healthy older women than men. This apparent sexual dimorphism in the adaptive response of skeletal muscle metabolism to EPA and DHA ingestion may be related to a greater propensity for females to incorporate ո-3 PUFA into human tissue and/or the larger dose of ingested ո-3 PUFA when expressed relative to body mass or lean body mass. Future experimental studies are warranted to characterise the optimal dosing and duration of ո-3 PUFA ingestion to prescribe tailored recommendations regarding n-3 PUFA nutrition for healthy musculoskeletal ageing into later life.

Association between Chronic Kidney Disease and Dynapenia in Elderly Koreans

Chronic kidney disease (CKD) is caused by various factors such as chronic inflammation, oxidative stress, and obesity. Loss of muscle strength and mass is a negative prognostic factor for CKD. Therefore, in this study, we aimed to investigate the association between CKD and dynapenia in the Korean elderly. To this end, we analyzed 7029 participants from the 2014-2019 Korean National Health and Nutrition Examination Survey (KNHANES) aged ≥65 years. After adjusting for all of the covariates that could affect the results, such as physical examinations, lifestyle factors, and exercise, the association between CKD and dynapenia was found to be significant, at 1.207 (95% CI: 1.056-1.379) in CKD stage 2 and 1.790 (95% CI: 1.427-2.246) in CKD stage 3a-5. However, when sexes were analyzed separately, women were significant in both CKD stage 2 and stage 3-5 compared to normal, but only in stage 3-5 for men. Additionally, the prevalence of dynapenia increased significantly as the stage of CKD increased (normal, stage 2, and stage 3-5: 18.5%, 20.8%, and 32.3% in men and 27.5%, 34.4%, and 46.1% in women, respectively). Thus, CKD is significantly related to dynapenia, especially in women, when stratified by sex.

Causal influence of muscle weakness on cardiometabolic diseases and osteoporosis

The causal roles of muscle weakness in cardiometabolic diseases and osteoporosis remain elusive. This two-sample Mendelian randomization (MR) study aims to explore the causal roles of muscle weakness in the risk of cardiometabolic diseases and osteoporosis. 15 single nucleotide polymorphisms (SNPs, P < 5 × 10-8) associated with muscle weakness were used as instrumental variables. Genetic predisposition to muscle weakness led to increased risk of coronary artery disease (inverse variance weighted [IVW] analysis, beta-estimate: 0.095, 95% confidence interval [CI]: 0.023 to 0.166, standard error [SE]:0.036, P-value = 0.009) and reduced risk of heart failure (weight median analysis, beta-estimate: - 0.137, 95% CI - 0.264 to - 0.009, SE:0.065, P-value = 0.036). In addition, muscle weakness may reduce the estimated bone mineral density (eBMD, weight median analysis, beta-estimate: - 0.059, 95% CI - 0.110 to - 0.008, SE:0.026, P-value = 0.023). We found no MR associations between muscle weakness and atrial fibrillation, type 2 diabetes or fracture. This study provides robust evidence that muscle weakness is causally associated with the incidence of coronary artery disease and heart failure, which may provide new insight to prevent and treat these two cardiometabolic diseases.

[GDF5: a therapeutic candidate for combating sarcopenia]

Sarcopenia is a complex age-related muscular disease affecting 10 to 16 % of people over 65 years old. It is characterized by excessive loss of muscle mass and strength. Despite a plethora of studies aimed at understanding the physiological mechanisms underlying this pathology, the pathophysiology of sarcopenia remains poorly understood. To date, there is no pharmacological treatment for this disease. In this context, our team develop therapeutic approaches based on the GDF5 protein to counteract the loss of muscle mass and function in various pathological conditions, including sarcopenia. After deciphering one of the molecular mechanisms governing GDF5 expression, we have demonstrated the therapeutic potential of this protein in the preservation of muscle mass and strength in aged mice.

The combined effect of rowing exercise and the intake of functional foods containing inulin on muscle mass and bone mineral density in older Japanese women

AIM

Aging decreases muscle mass and bone mineral density (BMD), especially in older women. It has been reported that rowing and inulin intake positively affect muscle and bone, respectively. We examined the synergistic effect of rowing and functional food intake, including inulin, on lean body mass, BMD, and physical function parameters in older Japanese women.

METHODS

Fifty women aged 65-79 years were divided into four groups with or without inulin intake and rowing. The interventions were carried out for 12 weeks in each group. We assessed lean body mass and BMD using dual-energy X-ray absorptiometry at baseline and after the intervention and examined the changes in the values in each group.

RESULTS

Lean body mass in all groups decreased, and the change in lean body mass in the group with rowing and inulin intake was significantly smaller than that in the group without them (-0.05 ± 0.61; -0.83 ± 0.59 kg; P = 0.030). The BMD in the three intervention groups increased after the 12-week intervention. The change in BMD in each of the three intervention groups showed significant differences compared with the control group (Rowing + Inulin: P = 0.03; Rowing + No inulin: P = 0.01; No rowing + Inulin: P < 0.01).

CONCLUSIONS

Rowing and the intake of functional foods, including inulin, synergistically prevented a decrease in lean body mass. These factors, individually and additively, might increase BMD in older Japanese women. Geriatr Gerontol Int 2023; 23: 779-787.

Cirrhosis-related sarcopenia may not resolve after liver transplantation

Background & Aims

Sarcopenia has significant burden in cirrhosis and has been shown to worsen short-term post-liver transplantation (LT). This study aims to evaluate the long-term change in sarcopenia post-LT along with its associations and predictors.

Methods

A retrospective study of adult patients who underwent LT at a tertiary centre between 1/1/2009 and 12/31/2018. Relevant demographic and clinical data were collected. Skeletal muscle index (SMI) was calculated using standard of care computerised tomography (CT) scans pre- and post-LT. Sarcopenia was defined using previously established cut-points. The primary outcome was SMI change post-LT and secondary outcome was post-LT mortality.

Results

Out of 1165 patients, 401 met inclusion criteria (1,205 CT scans reviewed). The average age at transplant was 57 years; 63% were male. The average BMI was 28 kg/m2. Thirteen percent of females and 32% of males had sarcopenia pre-LT. Post-LT SMI declined by 4.7 cm2/m2 in the first year then by 0.39 cm2/m2 per year thereafter. Females had greater rate of decline in SMI after the first year compared with males (0.87 cm2/m2 per year vs. 0.17 cm2/m2 per year, respectively, p = 0.02). Post-LT physical rehabilitation, infection, and readmissions were not associated with SMI trajectory. At 3 years post-LT, 31% of females and 48% of males had sarcopenia. Baseline sarcopenia was the only predictor of long-term post-LT sarcopenia on multivariable analysis, but it was not associated with mortality.

Conclusions

Sarcopenia does not appear to resolve post-LT and likely worsens leading to nearly doubling its prevalence in those with long-term follow-up. Immediate post-LT physical rehabilitation was not associated with SMI trajectory in our cohort.

Impact and implications

The prevalence of sarcopenia is high among patients with cirrhosis; however, data are mixed on the impact of sarcopenia on post-liver transplant (LT) course and there have been no studies evaluating the long-term evolution of sarcopenia post-LT beyond 1 year. In this study, we analysed changes in muscle mass up to 3 years after transplant in 401 patients and found that sarcopenia did not resolve in most liver transplant recipients and skeletal muscle mass tended to worsen after transplant with the greatest decline in muscle mass in the first year post-LT. Interestingly, sarcopenia did not influence post-transplant outcomes. Future prospective studies are needed to further understand the natural course of sarcopenia post-LT to guide interventions aiming at reversing post-LT sarcopenia.

Body composition in male lifelong trained strength, sprint and endurance athletes and healthy age-matched controls

Introduction

Aging involves many physiological processes that lead to decreases in muscle mass and increases in fat mass. While regular exercise can counteract such negative body composition outcomes, masters athletes maintain high levels of exercise throughout their lives. This provides a unique model to assess the impact of inherent aging. The present study compared lean mass and fat mass in young and masters athletes from different sports to age-matched non-athletic individuals.

Methods

Participants included young (20-39 years, n = 109) and older (70-89 years, n = 147) competitive male athletes, and 147 healthy age-matched controls (young = 53, older = 94 males). Athletes were separated into strength (e.g., weightlifters, powerlifters), sprint (e.g., sprint runners, jumpers) and endurance (e.g., long-distance runners, cross-country skiers) athletic disciplines. Body composition was assessed by dual-energy x-ray absorptiometry (DXA). Upper and lower limb lean mass was combined for appendicular lean mass as well as appendicular lean mass index (ALMI; kg/m2). Individuals' scores were assessed against established cut-offs for low muscle mass, obesity, and sarcopenic obesity to determine prevalence in each group.

Results

ALMI was greater in young strength (0.81-2.36 kg/m2, ∼15% and 1.24-2.74 kg/m2, ∼19%) and sprint (95% CI = 0.51-1.61 kg/m2, ∼11% and 0.96-1.97 kg/m2, ∼15%) athletes than in endurance and controls, respectively (all P < 0.001). In masters athletes, only strength athletes had greater ALMI than endurance athletes, but both older strength and sprint athletes had greater ALMI than older controls (0.42-1.27 kg/m2, ∼9% and 0.73-1.67 kg/m2, ∼13%, respectively, both P < 0.001). Fat mass was significantly lower in sprint and endurance athletes compared to strength athletes and controls in both age-groups. Sarcopenic obesity was identified in one young (2%) and eighteen (19%) older controls, while only two older endurance athletes (3%) and one older strength athlete (2%) were identified.

Discussion

Lifelong competitive sport participation leads to lower prevalence of sarcopenic obesity than a recreationally active lifestyle. This is achieved in strength athletes by emphasizing muscle mass, while sprint and endurance athletes demonstrate low fat mass levels. However, all older athlete groups showed higher fat mass than the young groups, suggesting that exercise alone may not be sufficient to manage fat mass.

Diagnosis of sarcopenia on thoracic computed tomography and its association with postoperative survival after anatomic lung cancer resection

Computer tomography-derived skeletal muscle index normalized for height in conjunction with muscle density enables single modality-based sarcopenia assessment that accounts for all diagnostic criteria and cutoff recommendations as per the widely accepted European consensus. Yet, the standard approach to quantify skeletal musculature at the third lumbar vertebra is limited for certain patient groups, such as lung cancer patients who receive chest CT for tumor staging that does not encompass this lumbar level. As an alternative, this retrospective study assessed sarcopenia in lung cancer patients treated with curative intent at the tenth thoracic vertebral level using appropriate cutoffs. We showed that skeletal muscle index and radiation attenuation at level T10 correlate well with those at level L3 (Pearson's R = 0.82 and 0.66, p < 0.001). During a median follow-up period of 55.7 months, sarcopenia was independently associated with worse overall (hazard ratio (HR) = 2.11, 95%-confidence interval (95%-CI) = 1.38-3.23, p < 0.001) and cancer-specific survival (HR = 2.00, 95%-CI = 1.19-3.36, p = 0.009) of lung cancer patients following anatomic resection. This study highlights feasibility to diagnose sarcopenia solely by thoracic CT in accordance with the European consensus recommendations. The straightforward methodology offers easy translation into routine clinical care and potential to improve preoperative risk stratification of lung cancer patients scheduled for surgery.

Associations between physical activity, physical fitness, and body composition in adults living in Germany: A cross-sectional study

BACKGROUND & AIMS

Body composition (BC) changes with age and is associated with morbidity and mortality. A physically active lifestyle influences BC and represents an important predictor of successful aging. To emphasize this, the World Health Organization established activity recommendations for all age groups. We describe BC during adulthood using a cross-sectional sample from a German community and investigate the associations between physical activity (PA), physical fitness (PF), and BC.

METHODS

Data from 329 men and women aged 35 to 86 years were analyzed. PA was measured by questionnaire and classified into sport activity and habitual activity. PF was measured through physical performance tests and BC by bioelectrical impedance analysis. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated to represent height-adjusted BC. Associations between PA, PF, and BC were analyzed using linear regression models.

RESULTS

For both sexes, strength was positively associated with FFMI (♂: ß = 0.313; ♀: ß = 0.213) and phase angle (♂: ß = 0.357; ♀: ß = 0.409). For FMI, a significant negative association with strength was found only in women (ß = -0.189). Cardiorespiratory fitness showed a negative association with FMI (ß = -0.312) and FFMI (ß = -0.201) for men, while in women a positive association was found for FFMI (ß = 0.186). For coordination, a significant association with FMI was observed only in women (ß = -0.190). Regarding PA only one significant relationship between sport activity and FMI among women (ß = -0.170) was found.

CONCLUSIONS

In our sample, PF was closer related to BC than PA. Strength and cardiorespiratory fitness were the strongest predictors for BC. This supports the World Health Organization's activity recommendations to include both resistance and endurance training in the weekly sports program to maintain a healthy BC.

The Functional and Anatomical Impacts of Healthy Muscle Ageing

Even "healthy" muscle ageing is often associated with substantial changes in muscle form and function and can lead to increased injury risks and significant negative impacts on quality of life. However, the impacts of healthy muscle ageing on the fibre architecture and microstructure of different muscles and muscle groups throughout the lower limb, and how these are related to their functional capabilities, are not fully understood. Here, a previously established framework of magnetic resonance and diffusion tensor imaging was used to measure the muscle volumes, intramuscular fat, fibre lengths and physiological cross-sectional areas of 12 lower limb muscles in a cohort of healthily aged individuals, which were compared to the same data from a young population. Maximum muscle forces were also measured from an isokinetic dynamometer. The more substantial interpopulation differences in architecture and functional performance were located within the knee extensor muscles, while the aged muscles were also more heterogeneous in muscle fibre type and atrophy. The relationships between architecture and muscle strength were also more significant in the knee extensors compared to other functional groups. These data highlight the importance of the knee extensors as a potential focus for interventions to negate the impacts of muscle ageing.

Role of Fyn and the interleukin-6-STAT-3-autophagy axis in sarcopenia

Sarcopenia is the progressive loss of muscle mass wherein Fyn regulates STAT3 to decrease autophagy. To elucidate the role of inflammation in Fyn-STAT3-dependent autophagy and sarcopenia, here we aimed to investigate the underlying mechanisms using two mouse models of primary and secondary sarcopenia: (1) tail suspension and (2) sciatic denervation. In wild-type mice, the expression of Fyn and IL-6 increased significantly. The expression and phosphorylation levels of STAT3 were also significantly augmented, while autophagic activity was abolished. To investigate Fyn-dependency, we used tail suspension with Fyn-null mice. In tail-suspended wild-type mice, IL-6 expression was increased; however, it was abolished in Fyn-null mice, which maintained autophagy and the expression and ablation of STAT3 phosphorylation. In conclusion, Fyn was found to be associated with the IL-6-STAT3-autophagy axis in sarcopenia. This finding permits a better understanding of sarcopenia-associated metabolic diseases and the possible development of therapeutic interventions.

Estimation of Sarcopenia Indices in Women from Saudi Arabia in Relation to Menopause and Obesity: Cross-Sectional Comparative Study

Sarcopenia prevalence depends on the definition, and ethnicity must be considered when setting reference values. However, there is no specific cut-off for sarcopenia in Saudi women. Accordingly, we aimed to establish a cut-off value for sarcopenia in Saudi women. We determined the prevalence of sarcopenia in terms of low handgrip strength (HGS) in postmenopausal women using the EWGSOP2 value, redefined a specific cut-off for low HGS derived from Saudi premenopausal women, re-determined the prevalence of low HGS using the new cut-off, and analyzed the proportion of low HGS in women with obesity compared to those without obesity. Following EWGSOP2 guidelines, we defined probable sarcopenia and set new HGS values. We assessed HGS and body composition in 134 pre/postmenopausal women. Probable sarcopenia prevalence was calculated using EWGSOP2's HGS of 16 kg and new cut-offs from young premenopausal women without obesity. HGS 10 and 8 kg cut-offs were calculated from premenopausal Saudi women's mean -2 SDs and mean -2.5 SDs. Using the HGS 16 kg cut-off, sarcopenia prevalence was 44% in postmenopausal and 33.89% in premenopausal women. Applying the new HGS 10 kg and 8 kg cut-offs, the prevalence was 9.33% and 4%, respectively, in postmenopausal and 5% and 3.40%, respectively, in premenopausal women. Women with obesity had a higher proportion of low HGS across all cut-offs. We suggest that EWGSOP2 cut-offs may not be adaptable for Saudi women. Considering body composition differences between Saudis and Caucasians, our proposed HGS cut-offs appear more relevant.

The impact of body compositions on contrast medium enhancement in chest CT: a randomised controlled trial

Objective

To compare a fixed-volume contrast medium (CM) protocol with a combined total body weight (TBW) and body composition-tailored protocol in chest CT.

Methods and materials

Patients referred for routine contrast enhanced chest CT were prospectively categorised as normal, muscular or overweight. Patients were accordingly randomised into two groups; Group 1 received a fixed CM protocol. Group 2 received CM volume according to a body composition-tailored protocol. Objective image quality comparisons between protocols and body compositions were performed. Differences between groups and correlation were analysed using t-test and Pearson's r.

Results

A total of 179 patients were included: 87 in Group 1 (mean age, 51 ± 17 years); and 92 in Group 2 (mean age, 52 ± 17 years). Compared to Group 2, Group 1 showed lower vascular attenuation in muscular (mean 346 Hounsfield unit (HU) vs 396 HU; p = 0.004) and overweight categories (mean 342 HU vs 367 HU; p = 0.12), while normal category patients showed increased attenuation (385 vs 367; p = 0.61). In Group 1, strongest correlation was found between attenuation and TBW in muscular (r = -.49, p = 0.009) and waist circumference in overweight patients (r = -.50, p = 0.005). In Group 2, no significant correlations were found for the same body size parameters. In Group 1, 13% of the overweight patients was below 250 HU (p = 0.053).

Conclusion

A combined TBW and body composition-tailored CM protocol in chest CT resulted in more homogenous enhancement and fewer outliers compared to a fixed-volume protocol.

Advances in knowledge

This is, to our knowledge, the first study to investigate the impact of various body compositions on contrast medium enhancement in chest CT.

Investigating sources for variability in volunteer kinematics in a braking maneuver, a sensitivity analysis with an active human body model

Occupant kinematics during evasive maneuvers, such as crash avoidance braking or steering, varies within the population. Studies have tried to correlate the response to occupant characteristics such as sex, stature, age, and BMI, but these characteristics explain no or very little of the variation. Therefore, hypothesis have been made that the difference in occupant response stems from voluntary behavior. The aim of this study was to investigate the effect from other sources of variability: in neural delay, in passive stiffness of fat, muscle tissues and skin, in muscle size and in spinal alignment, as a first step towards explaining the variability seen among occupants in evasive maneuvers. A sensitivity analysis with simulations of the SAFER Human Body Model in braking was performed, and the displacements from the simulations were compared to those of volunteers. The results suggest that the head and torso kinematics were most sensitive to spinal alignment, followed by muscle size. For head and torso vertical displacements, the range in model kinematics was comparable to the range in volunteer kinematics. However, for forward displacements, the included parameters only explain some of the variability seen in the volunteer experiment. To conclude, the results indicate that the variation in volunteer vertical kinematics could be partly attributed to the variability in human characteristics analyzed in this study, while these cannot alone explain the variability in forward kinematics. The results can be used in future tuning of HBMs, and in future volunteer studies, when further investigating the potential causes of the large variability seen in occupant kinematics in evasive maneuvers.

The influence of Tai Chi exercise on the subjective well-being in the aged: the mediating role of physical fitness and cognitive function

This study investigated the effects of Tai Chi exercise on subjective well-being in the aged. The participants were randomly assigned to an experimental group or a control group. The experimental group received 12-week Tai Chi exercise while the control group maintain their original living habits. The participants' subjective well-being, physical fitness, self-control, and executive function were measured at baseline and after 12 weeks of Tai Chi exercise. Results: (1) Tai Chi exercise can positively affect the subjective well-being of the aged (F(1,78) = 37.699, p < 0.001); (2) Tai Chi exercise could affect the subjective well-being in the aged through the independent intermediary of physical fitness (95% CI=[0.115, 0.485]) and self-control (95% CI=[0.109, 0.433]); (3) Tai Chi exercise could indirectly affect the subjective well-being in the aged through the chain mediation of executive function and self-control (95% CI=[0.009, 0.104]). This study provides valuable insights into the potential benefits of Tai Chi exercise for subjective well-being in the aged.

Which trunk muscle parameter is the best predictor for physical function in older adults?

Background

Despite preliminary evidence demonstrating the relevance of trunk muscle strength for physical function in older adults, it is not clear which muscle-related trunk parameter is the best predictor for physical functions. Therefore, this study aimed to compare trunk muscle morphology or strength parameters regarding their predictive ability for physical functions.

Methods

Seventy-four older adults (38 men, 36 women, mean age 76.85 years) were tested for maximum absolute and relative isokinetic trunk flexion and extension strength, trunk lean mass, and trunk muscle quality. Functional assessment included normal and fast walking speed, repeated sit-to-stand transfer, timed up and go, and postural sway during a closed-feet and a semi-tandem stance adjusted for body height. Pearson's correlations were used to compare relationship between trunk strength adjusted and unadjusted for body weight to physical functions. Linear regression analysis including sex and age as co-variables was performed between trunk muscle and functional test parameters.

Results

Relative back extension strength was the most consistent significant predictor for all physical function tests (p = 0.004-0.04) except for postural sway. Relative trunk flexion strength was related to normal walking speed (p = 0.024). Trunk lean mass was related to timed up and go performance (p = 0.024).

Conclusion

Relative back extension strength is associated with better performance in nearly all standard tests for physical function in older adults, while trunk flexion strength and lean mass seem to play a minor role. Our findings emphasize the importance of trunk muscle strength, especially the back extensor muscles, for physical function in older adults.

A focus on leucine in the nutritional regulation of human skeletal muscle metabolism in ageing, exercise and unloading states

Muscle protein synthesis (MPS) and muscle protein breakdown (MPB) are influenced through dietary protein intake and physical (in)activity, which it follows, regulate skeletal muscle (SKM) mass across the lifespan. Following consumption of dietary protein, the bio-availability of essential amino acids (EAA), and primarily leucine (LEU), drive a transient increase in MPS with an ensuing refractory period before the next MPS stimulation is possible (due to the "muscle full" state). At the same time, MPB is periodically constrained via reflex insulin actions. Layering exercise on top of protein intake increases the sensitivity of SKM to EAA, therefore extending the muscle full set-point (∼48 h), to permit long-term remodelling (e.g., hypertrophy). In contrast, ageing and physical inactivity are associated with a premature muscle full set-point in response to dietary protein/EAA and contractile activity. Of all the EAA, LEU is the most potent stimulator of the mechanistic target of rapamycin complex 1 (mTORC1)-signalling pathway, with the phosphorylation of mTORC1 substrates increasing ∼3-fold more than with all other EAA. Furthermore, maximal MPS stimulation is also achieved following low doses of LEU-enriched protein/EAA, negating the need for larger protein doses. As a result, LEU supplementation has been of long term interest to maximise muscle anabolism and subsequent net protein accretion, especially when in tandem with resistance exercise. This review highlights current knowledge vis-à-vis the anabolic effects of LEU supplementation in isolation, and in enriched protein/EAA sources (i.e., EAA and/or protein sources with added LEU), in the context of ageing, exercise and unloading states.

Effects of a 12-week supervised resistance training program, combined with home-based physical activity, on physical fitness and quality of life in female breast cancer survivors: the EFICAN randomized controlled trial

PURPOSE

This study assessed the effects of 12-week supervised resistance training combined with home-based physical activity on physical fitness, cancer-related fatigue, depressive symptoms, health-related quality of life (HRQoL), and life satisfaction in female breast cancer survivors.

METHODS

A parallel-group, outcome assessor-blinded, randomized controlled trial included 60 female breast cancer survivors who had completed their core treatments within the previous 10 years. Through computer-generated simple randomization, participants were assigned to resistance training (RTG; two sessions/week for 12 weeks plus instructions to undertake ≥ 10,000 steps/d) or control (CG; ≥ 10,000 steps/d only). Outcomes were evaluated at baseline and week 12. Muscular strength was assessed with electromechanical dynamometry. A standardized full-body muscular strength score was the primary outcome. Secondary outcomes included cardiorespiratory fitness, shoulder mobility, cancer-related fatigue, depressive symptoms, HRQoL, and life satisfaction.

RESULTS

Thirty-two participants were assigned to RTG (29 achieved ≥ 75% attendance) and 28 to CG (all completed the trial). Intention-to-treat analyses revealed that the standardized full-body muscular strength score increased significantly in the RTG compared to the CG (0.718; 95% CI 0.361-1.074, P < 0.001, Cohen's d = 1.04). This increase was consistent for the standardized scores of upper-body (0.727; 95% CI 0.294-1.160, P = 0.001, d = 0.87) and lower-body (0.709; 95% CI 0.324-1.094, P = 0.001, d = 0.96) strength. There was no effect on cardiorespiratory fitness, shoulder flexion, cancer-related fatigue, depressive symptoms, HRQoL, or life satisfaction. The sensitivity analyses confirmed these results.

CONCLUSION

and implication for cancer survivors. In female breast cancer survivors who had completed their core treatments within the past 10 years, adding two weekly sessions of supervised resistance training to a prescription of home-based physical activity for 12 weeks produced a large increase in upper-, lower-, and full-body muscular strength, while other fitness components and patient-reported outcomes did not improve.

TRIAL REGISTRATION NUMBER

ISRCTN14601208.

Handgrip strength is a substitutive metric to the GLIM criteria-defined malnutrition and predicts long-term mortality among hospitalized patients with cirrhosis

BACKGROUND

Hospitalized patients with cirrhosis are prone to debilitating health conditions and fluid fluctuations, posing barriers to accurately obtain anthropometric measures and physical examinations as surrogates for muscle mass within the Global Leadership Initiative on Malnutrition (GLIM). We hypothesize the handgrip strength (HGS) would serve as a substitutive metric, by comparing the diagnostic consistency and prognostic accuracy with computed tomography-demarcated skeletal muscle index (SMI)-defined malnutrition according to the GLIM criteria.

METHODS

Patients with cirrhosis underwent a two-step approach involving nutrition risk screening and those fulfilling GLIM consensus were further diagnosed. The evaluation of muscle mass as one constituent contained in the GLIM criteria was conducted by SMI and HGS, respectively. Consistency test, Kaplan-Meier curve, and multivariate Cox regression were used to assess the performance of GLIM-SMI and GLIM-HGS.

RESULTS

Among 184 hospitalized patients with cirrhosis, 63 (34.2%) and 78 (42.4%) were diagnosed with malnutrition following GLIM-SMI and GLIM-HGS criteria, respectively. Considering the GLIM-SMI a gold standard, GLIM-HGS had a sensitivity of 87.3% and a specificity of 81.0%. GLIM-HGS criteria denoted good agreement (κ value = 0.858, P < 0.001) as compared with GLIM-SMI. Both criteria were independently associated with 1-year all-cause mortality, whereas GLIM-SMI showed slightly higher hazard ratios. Moreover, HGS positively correlated with SMI in the population alongside more pronounced correlation among patients at nutrition risk.

CONCLUSION

HGS may serve as a substitutive metric of muscle mass contained in the GLIM criteria to diagnose malnutrition and predict long-term mortality among patients with cirrhosis.

Developing a predictive equation of muscular age to evaluate muscle health in Chinese community-dwelling older women

Muscle health plays an important role in most common age-related diseases and injuries. To date, a standardized quantitative method to assess muscle health has not yet been developed. Principal component analysis was employed to develop a predictive equation of muscular age based on muscle health variables including skeletal muscle mass of lower limb, grip strength and maximal gait speed. Then validity of muscular age was tested by comparing chronological age to muscular age of the elderly. A predictive equation of muscular age was developed. Muscular age = 0.690 × chronological age - 1.245 × skeletal muscle mass of lower limb + 0.453 × grip strength - 1.291 × maximal walking speed + 40.547. Cross-sectional validity test showed that the predictive equation of muscular age is a valid method to assess muscle health. It is applicable not only to the normal elderly but to the elderly with pre-sarcopenia or sarcopenia.

Applicability of the seated step test for assessing thigh muscle sarcopenia in older individuals

Assessment of lower limb muscle mass and related functions in older individuals is important because of their essential role in maintaining locomotion and activities of daily living. Therefore, a simple and reliable method for assessing these parameters should be established. The seated step test is easy and safe and can be used to assess lower limb agility; however, its relationship to skeletal muscle mass and function remains unknown. The present study aimed to investigate the relationships between the seated step test and lower limb muscle mass and function. For the analysis, we included 85 participants aged 73.1 ± 6.0 years. The participants performed an alternate up-down leg step test for 10 s while seated in a chair. Lower limb muscle mass was measured using bioimpedance analysis. Skeletal muscle mass index (SMI) was calculated using the following equation: lower limb muscle mass (kg) / height2 (m2). As the muscle functional parameters, we measured the isometric knee extension peak torque (KEPT), knee flexion peak torque (KFPT), and rate of torque development (RTD) for isometric knee extension in all participants. The seated step test score had a significant relationship with KEPT, KFPT, and SMI, but not with RTD. In the single regression analysis, the seated step test significantly predicted KEPT, KFPT, and SMI. These results suggest that up-down seated step test can be a reliable method to estimate lower limb muscle size and function in older individuals.

Effects of high-intensity interval training on lean mass, strength, and power of the lower limbs in healthy old and young people

Introduction: Whether high-intensity interval training (HIIT) can improve lean mass, strength, and power of the lower limbs in young and older people is still under discussion. This study aimed to determine the effect of HIIT on lean mass, maximal strength, rate of force development (RFD), and muscle power of both lower limbs in healthy young and older adults. Secondarily, to compare the effects of HIIT between dominant vs. non-dominant lower limbs of each group. Materials and methods: Healthy older (n = 9; 66 ± 6 years; BMI 27.1 ± 3.1 kg m-2) and young (n = 9; 21 ± 1 years; BMI 26.2 ± 2.8 kg m-2) men underwent 12 weeks of HIIT (3x/week) on a stationary bicycle. The evaluations were made before and after the HIIT program by dual energy X-ray absorptiometry (DEXA), anthropometry, force transducer and, Sit-to-Stand test. The outcomes analyzed were limb lean mass, thigh circumference, maximal voluntary isometric strength, RFD (Time intervals: 0-50, 50-100, 100-200, and 0-200 ms), and muscle power in both lower limbs. Results: After 12 weeks of HIIT, non-dominant limb (NDL) showed increase in limb lean mass (p < 0.05) but without interaction (time*group). HIIT showed a gain in absolute maximal strength and also when adjusted for thigh circumference in the dominant lower limb (DL) in both groups. The RFD0-200 ms showed differences between groups but without interaction. The RFD0-50 ms of the NDL showed post-training improvements (p < 0.05) in both groups. Only the older group showed differences between DL vs. NDL in most of the RFD obtained post-intervention. In addition, post-HIIT muscle power gain was observed in both groups (p < 0.05), but mainly in older adults. Conclusion: HIIT promotes increases in lean mass, maximal strength, early RFD, and lower limb muscle power in healthy older and young individuals. The differences shown between the DL and the NDL must be analyzed in future studies.

Ageing, sport and physical activity participation in Scotland

Aim

As sport and physical activity are vital to support extended health spans, this study aimed to analyse the current trends in sports participation and physical activity rates among individuals aged 65 years and older in Scotland. Data were compared with the Chief Medical Officer (CMO) guidelines and analysed the influence of key factors on participation rates.

Methods

The study used data from the Scottish Health Survey and the Scottish Household Survey (2019) to investigate self-reported participation in physical activity and sports across different age groups. Descriptive statistics and cross-tabulations were used to analyse the relationships between participation rates and influencing factors. Participation data for Parkrun events in Scotland were also analysed for the years 2008-2018.

Results

The study found a clear decline in sports participation with age, with a steep decline after the age of 65, particularly in women. The majority of participation among individuals aged 65+ was in walking, with a sport participation rate of only 31.2% when walking was excluded. Physical activity and sport participation was lower in women across all age ranges but particularly so in the 75+ age group. The most popular sporting activities in the older age group were keep fit/aerobics, swimming and golf. Additionally, the study found that social deprivation had a major impact on sports participation rates, with the most deprived households exhibiting the lowest participation levels irrespective of age. The prevalence of loneliness was lower among individuals who participated in sports or adhered to the CMO guidelines for moderate/vigorous physical activity and strength-building exercises.

Discussion

The findings of this study have implications for promoting physical activity and sports participation among older adults, particularly in deprived communities. This study highlights the importance of balance exercises within sport and the need for more targeted efforts to increase participation rates among older adults. The study also emphasizes the positive impact of sports participation on reducing loneliness among older adults. Overall, the findings suggest the need for ongoing efforts to promote physical activity and sports participation among older adults to improve their overall health and well-being.

Coexistent GLIM-Defined Malnutrition and Sarcopenia Increase the Long-Term Mortality Risk in Hospitalized Patients with Decompensated Cirrhosis

INTRODUCTION

The synergistic impact of coexistent malnutrition and sarcopenia on morality in hospitalized patients with decompensated cirrhosis remains elusive. This prospective cohort study aimed to delineate the prevalence concerning coexistence of malnutrition and sarcopenia and the prognosticating role on long-term mortality among cirrhosis.

METHODS

Adult cirrhotic patients with decompensated episodes between 2019 and 2021 were consecutively enrolled. Malnutrition and sarcopenia were diagnosed according to the Global Leadership Initiative on Malnutrition (GLIM) criteria and the European Working Group on Sarcopenia in Older People (EWGSOP2) algorithm, respectively. The entire cohort was divided into three groups: non-malnutrition and non-sarcopenia (NN), malnutrition or sarcopenia, and coexistent malnutrition and sarcopenia (MS). Log-rank test and multivariate Cox regression model were utilized to evaluate survival status and independent risk factors for mortality, respectively.

RESULTS

Our findings indicated that malnutrition manifested in 44.6% of inpatients with decompensated cirrhosis, while sarcopenia presented in 16.4% of the entire cohort, indicative of a prevalence of 14.7% regarding coexistent malnutrition and sarcopenia. The Kaplan-Meier graphic demonstrated a significant difference regarding survival curves among the three groups, referring to the MS group presented with the lowest survival rate (log-rank test: p < 0.001). Moreover, coexistent malnutrition and sarcopenia were associated with nearly 4 times higher mortality risk (model 1: hazard ratio [HR] = 3.31, 95% confidence interval [CI]: 1.20-9.13, p = 0.020; model 2: HR = 4.34, 95% CI: 1.52-12.4, p = 0.006) in comparison with patients without any condition (NN group).

CONCLUSIONS

Malnutrition and sarcopenia had superimposed negative impacts on inpatients with decompensated cirrhosis. It is imperative to identify this vulnerable subset to provide prompt therapeutic intervention for better prognosis.

Long-term clinical outcomes in critically ill patients with sepsis and pre-existing low muscle mass: a retrospective cohort study

PURPOSE

Critically ill patients with sepsis account for significant disease morbidity and healthcare costs. Low muscle mass has been proposed as an independent risk factor for poor short-term outcomes, although its effect on long-term outcomes remains unclear.

METHODS

Retrospective cohort analysis of patients treated at a quaternary care medical center over 6 years (09/2014 - 12/2020). Critically ill patients meeting Sepsis-3 criteria were included, with low muscle mass defined by [Formula: see text] 5th percentile skeletal muscle index, measured at the L3 lumbar level (L3SMI) on Computed-Tomography (CT) scan ([Formula: see text] 41.6 cm2/m2 for males and [Formula: see text] 32.0 cm2/m2 for females). L3SMI was calculated by normalizing the CT-measured skeletal muscle area to the square of the patient's height (in meters). Measurements were taken from abdominal/pelvic CT scan obtained within 7 days of sepsis onset. The prevalence of low muscle mass and its association with clinical outcomes, including in-hospital and one-year mortality, and post-hospitalization discharge disposition in survivors, was analyzed. Unfavorable post-hospitalization disposition was defined as discharge to a location other than the patient's home.

RESULTS

Low muscle mass was present in 34 (23%) of 150 patients, with mean skeletal muscle indices of 28.0 ± 2.9 cm2/m2 and 36.8 ± 3.3 cm2/m2 in females and males, respectively. While low muscle mass was not a significant risk factor for in-hospital mortality (hazard ratio 1.33; 95% CI 0.64 - 2.76; p = 0.437), it significantly increased one-year mortality after adjusting for age and illness severity using Cox multivariate regression (hazard ratio 1.9; 95% CI 1.1 - 3.2; p = 0.014). Unfavorable post-hospitalization discharge disposition was not associated with low muscle mass, after adjusting for age and illness severity in a single, multivariate model.

CONCLUSION

Low muscle mass independently predicts one-year mortality but is not associated with in-hospital mortality or unfavorable hospital discharge disposition in critically ill patients with sepsis.

Functional fitness, lifestyle and demographic factors as predictors of perceived physical and mental health in older adults: A structural equation model

Over the past 50 years, socioeconomic development has brought a reduction in birth rates, an increase in life expectancy and consequently in the elderly population. For this reason, there has been an increasing focus on physical and mental health of the elderly, promoting the concept of healthy aging. The aim of this study was to explore the associations between perceived physical and mental health of older adults and a variety of determinants, such as demographic factors, physical functional fitness, physical activity level, adherence to the Mediterranean diet and anthropometric indices, through a structural equation modeling (SEM). A cross-sectional observational study involved 208 elderly (24 men and 184 women) over the age of 60, fully independent and autonomous. Perceived physical and mental health were assessed with the Short Form 12 questionnaire. Basic sociodemographic information was collected; anthropometric features were directly measured, functional fitness was assessed with the Senior Fitness Test, and physical activity level was determined through the International Physical Activity Questionnaire; adherence to Mediterranean Diet (MD) was also collected through the MEDAS questionnaire. The SEM analysis revealed that functional fitness, which was a latent variable of the model described by the six administered fitness tests, was a strong predictor both of perceived physical and perceived mental health in the sample of elderly. Physical activity level was as predictor of the perceived physical component, but not of the mental health, while score of metabolic equivalent task did not result a predictor, as well as the sociodemographic factors and adherence to MD. The present findings suggest that it would be strongly recommended for elderly subjects to engage in physical activity specifically targeted to aged populations, in order to enhance their fitness abilities and enable them to improve the perception of their own health status.

Effects of Power Training on Functional Capacity Related to Fall Risk in Older Adults: A Systematic Review and Meta-analysis

OBJECTIVE

Functional capacity is 1 of the main risk factors for falls among older adults. The aim of this systematic review and meta-analysis was to determine the effect of power training on functional capacity test (FCT) related to fall risk in older adults.

DATA SOURCES

Systematic searches were conducted in 4 databases, including PubMed, Web of Science, Scopus, and SPORTDiscus, from inception to November 2021.

STUDY SELECTION

Randomized controlled trials (RCTs) assessing the effect of power training on functional capacity compared with another type of training program or control group in older adults with the ability to exercise independently.

DATA EXTRACTION

Two independent researchers evaluated eligibility and used the PEDro scale to assess risk of bias. The information extracted was related to article identification (authors, country and year of publication), participant characteristics (sample, sex, and age), strength training protocols (exercises/intensity/weeks), and the outcome of the FCT used related to fall risk. The Cochran Q statistic and I2 statistics was used to assess heterogeneity. Random-effects model were conducted to pool the effect sizes expressed as mean differences (MD).

DATA SYNTHESIS

Twelve studies (478 subjects) were selected for systematic review. A meta-analysis comprised 6 studies (217 subjects) where the outcome measure was the 30-second Sit to Stand (30s-STS) test, and another comprised 4 studies (142 subjects) where the outcome measure was the timed Up and Go (TUG) test. There was an improvement in performance in favor of the experimental group in both the TUG subgroup (MD -0.31 s; 95% CI -0.63, 0.00 s; P=.05), and the 30s-STS subgroup (MD 1.71 reps; 95% CI -0.26, 3.67 reps; P=.09).

CONCLUSIONS

In conclusion, power training increases functional capacity related to fall risk further than other types of exercise in older adults.

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.

Predictive Ability of the 2-Minute Step Test for Functional Fitness in Older Individuals with Hypertension

BACKGROUND

The 2-minute step test (2MST) is a simple and inexpensive functional test that measures an individual's ability to perform continuous stepping up and down on a step platform for two minutes. This study evaluated the 2MST as a tool for assessing functional fitness in older individuals with hypertension and determined the correlation between the 2MST and physical fitness tests.

METHODS

A total of 91 older individuals with hypertension performed physical fitness tests, including the 2MST, 6-minute walk test (6MWT), five times sit-to-stand test (FTSST), grip strength and leg strength assessments, and timed up and go test (TUG) to collectively assess their physical fitness.

RESULTS

A cutoff score of ≤60 steps in the 2MST had 87.50% sensitivity and 70.59% specificity in predicting functional exercise performance in older individuals with hypertension. Additionally, the number of steps in the 2MST was positively correlated with the distance covered in the 6MWT, isometric grip strength, and isometric leg strength and negatively correlated with the duration of the FTSST and TUG.

CONCLUSIONS

A cutoff score of ≤60 steps in the 2MST predicted functional exercise performance in older individuals with hypertension with 87.50% sensitivity and 70.59% specificity and was correlated with other physical fitness tests, suggesting that the 2MST is a useful tool for assessing functional exercise performance.

Human milk extracellular vesicles enhance muscle growth and physical performance of immature mice associating with Akt/mTOR/p70s6k signaling pathway

Extracellular vesicles (EVs) play an important role in human and bovine milk composition. According to excellent published studies, it also exerts various functions in the gut, bone, or immune system. However, the effects of milk-derived EVs on skeletal muscle growth and performance have yet to be fully explored. Firstly, the current study examined the amino acids profile in human milk EVs (HME) and bovine milk EVs (BME) using targeted metabolomics. Secondly, HME and BME were injected in the quadriceps of mice for four weeks (1 time/3 days). Then, related muscle performance, muscle growth markers/pathways, and amino acids profile were detected or measured by grip strength analysis, rotarod performance testing, Jenner-Giemsa/H&E staining, Western blotting, and targeted metabolomics, respectively. Finally, HME and BME were co-cultured with C2C12 cells to detect the above-related indexes and further testify relative phenomena. Our findings mainly demonstrated that HME and BME significantly increase the diameter of C2C12 myotubes. HME treatment demonstrates higher exercise performance and muscle fiber densities than BME treatment. Besides, after KEGG and correlation analyses with biological function after HME and BME treatment, results showed L-Ornithine acts as a "notable marker" after HME treatment to affect mouse skeletal muscle growth or functions. Otherwise, L-Ornithine also significantly positively correlates with the activation of the AKT/mTOR pathway and myogenic regulatory factors (MRFs) and can also be observed in muscle and C2C12 cells after HME treatment. Overall, our study not only provides a novel result for the amino acid composition of HME and BME, but the current study also indicates the advantage of human milk on skeletal muscle growth and performance.

Validation of a Geriatric Bedside Swallowing Screen (GEBS): Protocol of a Prospective Cohort Study

BACKGROUND

Demographic changes will raise the need for specialized care of older patients. Oropharyngeal dysphagia has recently been declared a geriatric syndrome reflecting its multifactorial background. Alongside multimorbidity, sarcopenia, frailty, and disability, swallowing disorders increase with advancing age, with prevalence rates reported to be as high as 44% in acute geriatric hospital settings and 80% in long-term care facilities. Hence, systematic screening of older patients to diagnose dysphagia and initiate treatment is of paramount importance to prevent bolus death, aspiration pneumonia, and malnutrition and improve quality of life. Several screening tools have been evaluated in emergency and stroke units. However, no published dysphagia screening tool has been validated in the hospitalized, older adult population using a gold standard in dysphagia diagnostics as a reference test. The validation of the proposed test is a first step.

OBJECTIVE

The Geriatric Bedside Swallowing Screen (GEBS) study aims to validate a new screening tool developed specifically for older inpatients against an instrumental swallowing evaluation, the flexible endoscopic evaluation of swallowing (FEES), which is considered a gold standard. Primary outcomes to be evaluated are sensitivity and specificity for the GEBS in the detection of dysphagia in a mixed older adult population. The presence of dysphagia will be defined by an instrumental swallowing evaluation (FEES), analyzed by the standardized penetration-aspiration scale.

METHODS

To validate the GEBS, a prospective cohort study will be carried out. Two institutions, an acute geriatric department and a long-term care facility, will aim to recruit a total of 100 patients aged ≥75 years. After giving their informed consent, patients will undergo the full screening protocol described in the GEBS as well as an evaluation of swallowing function using the FEES. Investigators will be blinded to the results of the respective other testing. The analysis of pseudonymized data sets will be done by a third investigator. Outcomes to be considered are sensitivity, specificity, diagnostic odds ratio, positive and negative likelihood quotient, and the reliability of the proposed dysphagia screening tool using the κ coefficient.

RESULTS

Recruitment started in October 2022 and will end in April 2024. Data publication is planned for early 2025.

CONCLUSIONS

If proven to be a valid screening tool for the early detection of dysphagia, further studies including different older adult populations as well as studies to determine the impact of systematic dysphagia screening on parameters, such as rates of aspiration pneumonia or nutritional status, should be planned. Effective screening of dysphagia will lead to earlier detection of patients with impaired swallowing. Those who fail the screening will be referred to speech language pathology for further diagnosis, thus optimizing care while streamlining personnel resources.

TRIAL REGISTRATION

ISCRTN Registry ISRCTN11581931; https://www.isrctn.com/ISRCTN11581931.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/46252.

Centile reference curves of the ultrasound-based characteristics of the rectus femoris muscle composition in children at 4-11 years old

Quantitative diagnostic ultrasound has been proposed as a way to characterize muscle structure, but there is a lack of normative data for children. This study aims to establish age-specific normal ranges for echo-intensity (EI), cross-sectional area (CSA), muscular thickness (MT), and subcutaneous adipose thickness (SAT) values of the rectus femoris muscle in typically developing children. The study recruited 497 children (288 boys and 209 girls) aged 4-10.9 years (mean age 7.39 years), and muscle parameters were measured using 2D B-mode ultrasound. Percentile values and reference curves were calculated using the Lambda, Mu, and Sigma method (LMS). The results showed small variation between measurements for boys compared to girls, with the most significant difference in EI, CSA, and MT values. EI decreased with age, with the most pronounced curve in boys. SAT increased in both sexes, with a slightly higher increase in girls after the age of 9.0 years. This study provides the first age-specific reference norms for the rectus femoris muscle architecture in children, and further research is needed to validate these curves and determine their clinical utility.

Correlation between bone mineral density and sarcopenia in US adults: a population-based study

INTRODUCTION

In the aging process of the body, in addition to changes in fat and muscle content, there is also bone loss, implying the possibility of a strong muscle-bone-lipid link. In this study, we initially investigated the relationship between lumbar BMD and low muscle mass and the relationship between "muscle-bone-lipid."

METHODS

The datasets from the National Health and Nutrition Examination Survey (NHANES) 2011-2018 were used in a cross-sectional investigation. BMD and appendicular skeletal muscle (ASM) were measured by dual-energy X-ray absorptiometry (DXA), and appendicular skeletal muscle was adjusted by body mass index (BMI) as a marker of sarcopenia. Weighted multivariate regression and logistic regression analysis were used to explore the independent relationship between lumbar BMD and sarcopenia. Fitted smoothing curves and threshold effect analysis were used to describe the nonlinear relationship.

RESULT

In 8386 participants with ages 20-59 years, there was a negative association between lumbar BMD and sarcopenia. In the fully adjusted model, the risk of developing sarcopenia decreased by 93% for each 1-unit increase in lumbar BMD (OR = 0.07, 95%CI 0.03-0.20). The risk of sarcopenia was 58% lower in participants in the highest quartile of lumbar BMD than in those in the lowest quartile (OR = 0.42, 95%CI 0.27-0.64). This negative association was more pronounced in the population of women with BMI ≥ 25.

CONCLUSION

Our findings suggest that lumbar BMD is negatively associated with sarcopenia in US adults. The dynamic balance between "muscle-bone-lipid" is likely to be related to the pathogenesis of bone loss.

Exercise snacking to improve physical function in pre-frail older adult memory clinic patients: a 28-day pilot study

BACKGROUND

Finding innovative yet feasible ways of preventing physical and cognitive decline in those at risk is a critical global challenge, with exercise being championed as a key precursor to robust health in later life. Exercise snacking, here defined as short bouts of sporadic [muscle-strengthening] exercise, is one such strategy designed to overcome typical participation barriers observed in older adults. This study examined the acceptability of exercise snacking amongst pre-frail older adults and explored the efficacy of this approach in improving physical function.

METHODS

In this single group design, 21 pre-frail outpatients with mild-cognitive impairment were recruited from a UK memory clinic. To be eligible, participants were aged ≥ 65-years who scored 3-8 (inclusive) on the short physical performance battery (SPPB) and were not regularly engaging in sport or exercise. Participants completed a 28-day, twice daily, exercise snacking intervention, consisting of five muscle-strengthening exercises, with the aim being to complete as many repetitions as possible of each exercise in a minute. Acceptability of the intervention was measured quantitatively and qualitatively using a survey and topic guide informed by the Theoretical Framework of Acceptability. Pre- and post-intervention physical function was measured using the SPPB, timed up-and-go (TUG), and 60s standing balance and sit-to-stand tests.

RESULTS

Eighteen participants provided follow-up data and showed 85% adherence to the exercise snacking intervention, measured as the proportion of all sessions completed out of a possible 56. Participants rated the intervention as highly acceptable (4.6/5) suggesting it supported their self-efficacy (4.3/5) was enjoyable (4.1/5) and had a low burden (2.1/5). Qualitative findings suggested the ease of use, flexibility of the programme, and perceived effectiveness was important, and particularly useful for non-exercisers. Changes in SPPB score (8(1) vs. 9(3), p < 0.01), TUG (11.32(4.02) vs. 9.18(5.25) seconds, p < 0.01) and in the 60-second sit-to-stand test (17 ± 5 vs. 23 ± 7 repetitions, p < 0.01) were seen between baseline and follow-up.

CONCLUSIONS

Exercise snacking is an acceptable and potentially efficacious format of exercise for pre-frail memory clinic attendees who are at heightened risk of falling and frailty. Large scale randomised controlled trials are required to confirm whether exercise snacking is effective in the short and long term.

CLINICALTRIALS

GOV REGISTRATION

NCT05439252 (30/06/2022).