Sarcopenia and health-related outcomes: an umbrella review of observational studies

Knowledge, awareness, behaviours, beliefs, attitudes, and perceptions of older Australians regarding muscle health and sarcopenia: A national survey

OBJECTIVE

This study evaluated older Australians understanding, awareness, knowledge, perceptions, behaviours, beliefs and attitudes towards muscle health and sarcopenia, and barriers towards exercise and nutrition as prevention options.

METHODS

A national, anonymous 41-question, online purpose-designed survey covering the concepts outlined in the study objective was conducted from March-May 2024.

RESULTS

1261 adults (≥50-y) aged 50-94 years participated. Low muscle strength and poor function were the most common criteria associated with poor muscle health. Knowledge of common signs/symptoms, risk factors, consequences, and effective treatments was generally high. However, there was uncertainty about unintentional weight loss as a risk factor, increased risk for infection/reduced immunity and chronic conditions as consequences, and ineffective treatments options (only 5-12 % recognised any form of exercise, aerobic exercise and eating more fruits/vegetables as ineffective treatments). Only 8.9 % reported their doctor had discussed muscle health but 82-95 % would act if they received information on risk factors or if informed they were at risk for poor muscle health. Two-thirds recognised sarcopenia as a serious condition, with 48 % concerned about its potential impact, despite 90 % acknowledging muscle health is very important to maintain. Only around half believed they had sufficient knowledge and confidence to adopt lifestyle changes to reduce their risk, with motivation the leading barrier to engaging in exercise or dietary strategies to optimize muscle health.

CONCLUSION

Older Australians recognize the importance of muscle health, understand key strategies to manage it and would act if identified to be at risk, but many lack knowledge and confidence to adopt lifestyle changes to improve their muscle health.

Prevalence of sarcopenia and its association with clinical features and health-related quality of life in Brazilian women with systemic lupus erythematosus

OBJECTIVES

To assess the prevalence of sarcopenia and examine its association with clinical features, health-related quality of life (HRQoL), muscle-specific strength and body composition in patients with systemic lupus erythematosus (SLE).

METHODS

In this cross-sectional multicentre study, women with SLE (18-50 years old) were included. Data collected included clinical features and HRQoL. Muscle strength was assessed using the handgrip test (kg), appendicular skeletal muscle mass index (ASMI, kg/m²) was measured using dual-energy X-ray absorptiometry. Physical performance was assessed using the timed-up-and-go test (TUG, seconds). Sarcopenia was defined by the European Working Group on Sarcopenia in Older People-2 criteria. The muscle-specific strength was evaluated by dividing their arm strength by their lean arm mass. Pearson's or Spearman's correlation coefficients were performed (accepted at p<0.05).

RESULTS

Seventy-three SLE women were included, with median (IQR) age and disease duration of 37 (30-44) years old and 10.0 (4.0-16.8) years, respectively. Most of the patients (83.5%) had inactive or low disease activity and 31.0% presented a disease damage index score ≥1. Mean (±SD) handgrip strength, ASMI and muscle-specific strength was 25.58±8.31 kg, 6.62±0.97 kg/m² and 6.6±2.3, respectively. Median TUG was 6.9 (6.1-8.2) s. The prevalence of probable sarcopenia was 11.1%, and sarcopenia was 2.7%. Lower muscle strength, lower muscle-specific strength and lower physical performance, as well as sarcopenia, were correlated with worse HRQoL (p<0.05).

CONCLUSION

In Brazilian patients with SLE with inactive or low disease activity, the prevalence of sarcopenia was low. However, low muscle strength, low muscle-specific strength and low physical performance were correlated with worse HRQoL, emphasising the need for muscle strength assessments in SLE management.

Development of an Algorithm to Predict Appendicular Lean Mass Index From Regional Spine and Hip Dxa Scans

INTRODUCTION

Sarcopenia is characterized by progressive muscle loss with reduced physical function and/or reduced muscle strength. Operational definitions of sarcopenia include a measurement of muscle mass, most often from dual-energy X-ray absorptiometry (DXA)-derived appendicular lean mass. Appendicular lean mass can be derived from whole-body dual-DXA scans; however, these scans are performed less commonly than hip and spine scans as part of clinical care. The objective of our study was to develop an algorithm to predict appendicular lean mass index (ALMI) from regional spine and hip dual-energy X-ray absorptiometry (DXA) scans.

METHODS

We performed a retrospective cross-sectional study using a subset of patients from the Manitoba Bone Mineral Density Registry who had hip, spine, and whole-body DXA scans at the same visit. We developed the algorithm using the following candidate covariates: age, sex, height, weight, DXA-derived spine and hip fat fraction, DXA-derived spine and hip tissue thickness. We internally validated the algorithm using the bootstrap method. Mean bootstrap parameter estimates were used as the final equation.

RESULTS

DXA scans from 676 patients were included in the analytic dataset. Mean ALMI was 6.73 (SD 1.43) kg/m2. The final predictive model included sex, age, height, weight, spine fat fraction and hip fat fraction. Sex also acted as an interaction term on weight and hip fat fraction. After bootstrap validation, model adjusted R2 was 0.863, root mean square error was 0.529 kg/m2, and AUROC to predict low ALMI per the European Working Group on Sarcopenia version 2 was 0.88.

CONCLUSION

Hip and spine DXA scans can be used to predict appendicular lean mass index. Future studies should test whether these predictions can be used to assess relationships between sarcopenia and other clinical conditions.

Applying both the 30-s and the 5-repetition sit-to-stand tests captures dissimilar groups and a broader spectrum of physical abilities in mobility-limited older individuals: results from the BIOFRAIL study

PURPOSE

We aimed to assess differences among older patients demonstrating low STS performance in the 30 s-STS and/or the 5r-STS.

METHODS

30 s-STS and 5r-STS were used to assess lower limb muscle strength and function in older adults. Analysis involved 376 patients (≥ 65 years) from a geriatric outpatient clinic for fall assessment.

RESULTS

The mean age of patients was 79.8 (± 6.1) years (67% female). In total, 40.6% had low STS performance with 9.3% presenting only low 30 s-STS, 9.8% only low 5r-STS, and 21.5% low STS performance in both tests. Patients with low STS performance in both tests had lower gait speed, were more often frail, and had more prior falls compared to patients with low STS performance in one test only.

CONCLUSION

The two STS tests are not interchangeable, and the use of both STS tests capture a wider range of physical abilities in mobility-limited older adults.

CLINICAL TRIAL REGISTRATION

NCT05795556.

The association between daily movement behavior and adjusted handgrip strength in post-menopausal women

Background

The factors driving the sarcopenia phenotype in post-menopausal women remain partly elusive. We thus investigated the associations of physical activity, sedentary behavior, and metabolic biomarkers with handgrip strength (HGS) as a marker of probable sarcopenia in Saudi post-menopausal women.

Methods

We recruited 268 post-menopausal women aged 50 years or above. Physical activity was assessed using Global Physical Activity Questionnaire (GPAQ), and body composition was measured with a BIA device. Blood samples were used to measure cholesterol and triglyceride levels. Blood pressure and waist circumference (WC) were measured. HGS was measured using a digital HGS dynamometer and an HGS < 16 kg was used to define probable sarcopenia. We applied the ordinary least squares (OLS) regression approach for the dependent variables HGS, HGS relative to skeletal muscle mass (SMM) and HGS relative to fat-to-mass ratio (FMR).

Results

Physical activity was positively associated with HGS, and sedentary behavior was negatively associated with HGS (p < 0.05). HGS relative to body mass index (BMI) and SMM revealed significant negative relationships with WC (p < 0.05). Taking into account age and FMR, the association with HGS or HGS/SMM existed for physical activity (p < 0.05), sedentary behavior (p < 0.01), and WC (p < 0.001).

Conclusion

Altogether, we report that high physical activity, low sedentary behavior and low WC are negatively associated with a risk of low HGS among Saudi post-menopausal women.

Health outcomes of sarcopenia: a consensus report by the outcome working group of the Global Leadership Initiative in Sarcopenia (GLIS)

The Global Leadership Initiative in Sarcopenia (GLIS) aims to standardize the definition and diagnostic criteria for sarcopenia into one unifying, common classification. Among other actions to achieve this objective, the GLIS has organized three different working groups (WGs), with the WG on outcomes of sarcopenia focusing on reporting its health outcomes to be measured in clinical practice once a diagnosis has been established. This includes sarcopenia definitions that better predict health outcomes, the preferred tools for measuring these outcomes, and the cutoffs defining normal and abnormal values. The present article synthesizes discussions and conclusions from this WG, composed of 13 key opinion leaders from different continents worldwide. Results rely on systematic reviews, meta-analyses, and relevant cohort studies in the field. With a high level of evidence, sarcopenia is significantly associated with a reduced quality of life, a higher risk of falls and fractures and a higher risk of mortality. Sarcopenia has been moderately associated with a higher risk of reduced instrumental activities of daily living (IADL). However, the GLIS WG found only inconclusive level of evidence to support associations between sarcopenia and higher risks of hospitalization, nursing home admission, mobility impairments, and reduced basic activities of daily living (ADL). This limitation underscores the scarcity of longitudinal studies, highlighting a barrier to understanding its progression and implications over time.

Nutrition and Physical Activity in Musculoskeletal Health

A balanced diet and regular physical activity are essential for maintaining musculoskeletal health. Key nutrients such as calcium, vitamin D, and protein are especially important for preventing falls and fractures. While the benefits of these nutrients are well-established, other dietary components have not been studied as extensively. For instance, vegetables, which are rich in nutrients vital for muscle and bone health, play a crucial role in preventing falls and fractures. Over recent decades, a great emphasis has been given to the combinations of nutrients and foods in dietary patterns that may have synergistic or antagonistic effects. Despite the challenges in researching the impact of nutrition and physical activity on musculoskeletal health due to the extensive heterogeneity of the results, healthcare professionals should continue to promote healthy eating and regular physical activity, and these principles should be emphasized in public health initiatives. Ultimately, a sufficient and balanced diet, abundant in plant-based foods and low in processed or discretionary foods, along with consistent physical activity, remains the most effective strategy for the prevention of musculoskeletal issues. This article aims to review the updated literature of recent years on the links between nutrition and physical activity with bone and skeletal muscle health.

Patient-reported outcomes in sarcopenia: An ICFSR task force report

The International Conference on Frailty and Sarcopenia Research (ICFSR) Task Force convened in March 2024 to address patient-reported outcomes measures (PROMs) in the field of sarcopenia. PROMs are crucial to enhance healthcare services at both individual and societal levels. PROMs complement objective outcome measures by capturing insights that patients are best suited to judge. In recent years, there has been an increase in the recognition of PROMs' importance within clinical trials by pharmaceutical industries and regulatory agencies. Consequently, it has become imperative to develop valid and reliable tools tailored to capture various aspects of patient's experience and health status. This report aims to present the state-of-the-art available and validated PROMs for sarcopenia that can be used within clinical settings by various stakeholders, and to highlight several research gaps and barriers that need to be addressed to expedite and improve the use of these outcome measures within the context of clinical trials.

Associations Between Adherence to the Mediterranean Diet and Incident Sarcopenia in Prospective Cohort Studies

The loss of skeletal muscle mass and strength, known as sarcopenia, is prevalent in older adults and linked to an increased risk of disability, frailty, and early mortality. Muscle health is crucial for the functionality and independence of older adults. As the aging population continuously grows, finding cost-effective strategies for preventing and treating sarcopenia is an important public health priority. While nutrition is recognized as a key factor in the development of sarcopenia, its role in preventing and treating the condition is still under investigation. In recent decades, nutritional research has shifted from a focus on individual nutrients or healthy foods to examining the combination of nutrients and foods in dietary patterns, along with their potential synergistic and antagonistic effects. A balanced diet and regular participation in physical activity are essential for maintaining musculoskeletal health. One of the healthy eating patterns with the greatest evidence of multiple health benefits is the Mediterranean diet, which has also been linked to positive effects on muscle function in observational studies. However, there is a lack of intervention studies. This review explores the updated evidence from longitudinal prospective studies on associations between adherence to the Mediterranean diet and sarcopenia in order to promote preventive and intervention strategies for healthy muscle aging.

Comparison of the performance of instruments for screening sarcopenia in older adults

AIM

To compare the performance of the SARC-F and SARCCalf questionnaires in sarcopenia screening and their relationship with clinical and sociodemographic aspects of older adults.

METHODS

Analytical cross-sectional study carried out with 739 elderly people in the community. Clinical, sociodemographic, anthropometric data and screening for signs suggestive of sarcopenia were obtained using the SARC-F and SARCCalf.

RESULTS

Evaluation by method showed a difference in the proportion of positive results for the SARC-F regarding female sex (71.7; p = 0.001), among older adults who did not have a partner (49.7; p < 0.001), and osteoarticular diseases (13.4; p < 0.001). On the other hand, the SARCCalf identified a higher proportion of positive results among older adults at risk of malnutrition (12.2; p < 0.001).

CONCLUSION

The performance of the instruments varied according to the clinical and sociodemographic characteristics of the population, and it is up to professionals to consider these aspects when using them.

A single bout of prior resistance exercise attenuates muscle atrophy and declines in myofibrillar protein synthesis during bed-rest in older men

Impairments in myofibrillar protein synthesis (MyoPS) during bed rest accelerate skeletal muscle loss in older adults, increasing the risk of adverse secondary health outcomes. We investigated the effect of prior resistance exercise (RE) on MyoPS and muscle morphology during a disuse event in 10 healthy older men (65-80 years). Participants completed a single bout of unilateral leg RE the evening prior to 5 days of in-patient bed-rest. Quadriceps cross-sectional area (CSA) was determined prior to and following bed-rest. Serial muscle biopsies and dual stable isotope tracers were used to determine rates of integrated MyoPS (iMyoPS) over a 7 day habitual 'free-living' phase and the bed-rest phase, and rates of acute postabsorptive and postprandial MyoPS (aMyoPS) at the end of bed rest. Quadriceps CSA at 40%, 60% and 80% of muscle length significantly decreased in exercised (EX) and non-exercised control (CTL) legs with bed-rest. The decline in quadriceps CSA at 40% and 60% of muscle length was attenuated in EX compared with CTL. During bed-rest, iMyoPS rates decreased from habitual values in CTL, but not EX, and were significantly different between legs. Postprandial aMyoPS rates increased above postabsorptive values in EX only. The change in iMyoPS over bed-rest correlated with the change in quadriceps CSA in CTL, but not EX. A single bout of RE attenuated the decline in iMyoPS rates and quadriceps atrophy with 5 days of bed-rest in older men. Further work is required to understand the functional and clinical implications of prior RE in older patient populations. KEY POINTS: Age-related skeletal muscle deterioration, linked to numerous adverse health outcomes, is driven by impairments in muscle protein synthesis that are accelerated during periods of disuse. Resistance exercise can stimulate muscle protein synthesis over several days of recovery and therefore could counteract impairments in this process that occur in the early phase of disuse. In the present study, we demonstrate that the decline in myofibrillar protein synthesis and muscle atrophy over 5 days of bed-rest in older men was attenuated by a single bout of unilateral resistance exercise performed the evening prior to bed-rest. These findings suggest that concise resistance exercise intervention holds the potential to support muscle mass retention in older individuals during short-term disuse, with implications for delaying sarcopenia progression in ageing populations.

Thoracic Sarcopenia was a Poor Prognostic Predictor in Patients Receiving Immunotherapy for Advanced Non-small-cell Lung Cancer

RATIONALE AND OBJECTIVES

Sarcopenia, as measured at the level of the third lumbar (L3) has been shown to predict the survival of cancer patients. However, many patients with advanced non-small cell lung cancer (NSCLC) do not undergo routine abdominal imaging. The objective of this study was to investigate the association of thoracic sarcopenia with survival outcomes among patients who underwent immunotherapy for NSCLC.

MATERIALS AND METHODS

In this retrospective study, patients who initiated immunotherapy for advanced NSCLC from 2019 to 2022 were enrolled. and detailed patient data were collected. Cross sectional skeletal muscle area was calculated at the fifth thoracic vertebra (T5) on pretreatment chest computed tomography (CT) scan. Gender-specific lowest quartile values was used to define sarcopenia. The risk factors were analyzed using Cox analyses. The log-rank test and the random survival forest (RSF) were used to compare progression free survival (PFS). The model's performance was assessed using calibration curve and the receiver operating characteristic curve (ROC).

RESULTS

A total of 242 patients was included (discovery cohort n = 194, validation cohort n = 48). In the discovery cohort, patients with sarcopenia exhibited significantly poorer PFS (p < 0.001) than patients without sarcopenia. Univariate cox regression revealed that sarcopenia, lung cancer stage, body mass index, smoking status, and neutrophil-to-lymphocyte ratio were predictors of poor PFS. A RSF model was constructed based on the aforementioned parameters, to evaluate the model's efficacy, the ROC curve was utilized. with an area under the curve for predicting 6-month PFS of 0.68 and for 12-month PFS of 0.69. The prediction models for survival outcomes built by the discovery cohort showed similar performance in the validation cohort.

CONCLUSION

Sarcopenia at T5 is independent prognostic factors in patients who received immunotherapy for advanced NSCLC.

Frailty and rheumatic diseases: evidence to date and lessons learned

Frailty represents a dynamic multisystem state of reduced physiological reserve that increases vulnerability to adverse health outcomes. Frailty occurs prematurely in adults with immune-mediated rheumatic diseases and is emerging as an important risk factor for adverse outcomes in these conditions. In this Series paper, we present a conceptual overview of frailty and its prevalence among patients with immune-mediated rheumatic diseases. We discuss putative mechanisms of frailty relevant to these diseases, tools for frailty measurement, and potential implications of frailty assessment for clinical care. We also explore the complex inter-relationship between frailty, inflammation, and disease activity in immune-mediated rheumatic diseases. As insight is gained into the epidemiology and mechanisms of frailty among patients with immune-mediated inflammatory rheumatic diseases, the possibility of targeting frailty with an intervention that could complement standard disease-modifying therapies to prevent adverse outcomes and improve health-related quality of life becomes closer to reality.

Sarcopenia diagnosis using skeleton-based gait sequence and foot-pressure image datasets

Introduction

Sarcopenia is a common age-related disease, defined as a decrease in muscle strength and function owing to reduced skeletal muscle. One way to diagnose sarcopenia is through gait analysis and foot-pressure imaging.

Motivation and research gap

We collected our own multimodal dataset from 100 subjects, consisting of both foot-pressure and skeleton data with real patients, which provides a unique resource for future studies aimed at more comprehensive analyses. While artificial intelligence has been employed for sarcopenia detection, previous studies have predominantly focused on skeleton-based datasets without exploring the combined potential of skeleton and foot pressure dataset. This study conducts separate experiments for foot-pressure and skeleton datasets, it demonstrates the potential of each data type in sarcopenia classification.

Methods

This study had two components. First, we collected skeleton and foot-pressure datasets and classified them into sarcopenia and non-sarcopenia groups based on grip strength, gait performance, and appendicular skeletal muscle mass. Second, we performed experiments on the foot-pressure dataset using the ResNet-18 and spatiotemporal graph convolutional network (ST-GCN) models on the skeleton dataset to classify normal and abnormal gaits due to sarcopenia. For an accurate diagnosis, real-time walking of 100 participants was recorded at 30 fps as RGB + D images. The skeleton dataset was constructed by extracting 3D skeleton information comprising 25 feature points from the image, whereas the foot-pressure dataset was constructed by exerting pressure on the foot-pressure plates.

Results

As a baseline evaluation, the accuracies of sarcopenia classification performance from foot-pressure image using Resnet-18 and skeleton sequences using ST-GCN were identified as 77.16 and 78.63%, respectively.

Discussion

The experimental results demonstrated the potential applications of sarcopenia and non-sarcopenia classifications based on foot-pressure images and skeleton sequences.

Identification of Predictors of Sarcopenia in Older Adults Using Machine Learning: English Longitudinal Study of Ageing

Background: After its introduction in the ICD-10-CM in 2016, sarcopenia is a condition widely considered to be a medical disease with important consequences for the elderly. Considering its high prevalence in older adults and its detrimental effects on health, it is essential to identify its risk factors to inform targeted interventions. Methods: Taking data from wave 2 of the ELSA, using ML-based methods, this study investigates which factors are significantly associated with sarcopenia. The Minimum Redundancy Maximum Relevance algorithm has been used to allow for an optimal set of features that could predict the dependent variable. Such a feature is the input of a ML-based prediction model, trained and validated to predict the risk of developing or not developing a disease. Results: The presented methods are suitable to identify the risk of acquired sarcopenia. Age and other relevant features related with dementia and musculoskeletal conditions agree with previous knowledge about sarcopenia. The present classifier has an excellent performance since the "true positive rate" is 0.81 and the low "false positive rate" is 0.26. Conclusions: There is a high prevalence of sarcopenia in elderly people, with age and the presence of dementia and musculoskeletal conditions being strong predictors. The new proposed approach paves the path to test the prediction of the incidence of sarcopenia in older adults.

Use of automated assessment for determining associations of low muscle mass and muscle loss with overall survival in patients with colorectal cancer - A validation study

BACKGROUND

Low muscle mass and skeletal muscle mass (SMM) loss are associated with adverse patient outcomes, but the time-consuming nature of manual SMM quantification prohibits implementation of this metric in clinical practice. Therefore, we assessed the feasibility of automated SMM quantification compared to manual quantification. We evaluated both diagnostic accuracy for low muscle mass and associations of SMM (change) with survival in colorectal cancer (CRC) patients.

METHODS

Computed tomography (CT) images from CRC patients enrolled in two clinical studies were analyzed. We compared i) manual vs. automated segmentation of preselected slices at the third lumbar [L3] vertebra ("semi-automated"), and ii) manual L3-slice-selection + manual segmentation vs. automated L3-slice-selection + automated segmentation ("fully-automated"). Automated L3-selection and automated segmentation was performed with Quantib Body Composition v0.2.1. Bland-Altman analyses, within-subject coefficients of variation (WSCVs) and Intraclass Correlation Coefficients (ICCs) were used to evaluate the agreement between manual and automatic segmentation. Diagnostic accuracy for low muscle mass (defined by an established sarcopenia cut-off) was calculated with manual assessment as the "gold standard". Using either manual or automated assessment, Cox proportional hazard ratios (HRs) were used to study the association between changes in SMM (>5% decrease yes/no) during first-line metastatic CRC treatment and mortality adjusted for prognostic factors. SMM change was also assessed separately in weight-stable (<5%, i.e. occult SMM loss) patients.

RESULTS

In total, 1580 CT scans were analyzed, while a subset of 307 scans were analyzed in the fully-automated comparison. Included patients (n = 553) had a mean age of 63 ± 9 years and 39% were female. The semi-automated comparison revealed a bias of -2.41 cm2, 95% limits of agreement [-9.02 to 4.20], a WSCV of 2.25%, and an ICC of 0.99 (95% confidence intervals (CI) 0.97 to 1.00). The fully-automated comparison method revealed a bias of -0.08 cm2 [-10.91 to 10.75], a WSCV of 2.85% and an ICC of 0.98 (95% CI 0.98 to 0.99). Sensitivity and specificity for low muscle mass were 0.99 and 0.89 for the semi-automated comparison and 0.96 and 0.90 for the fully-automated comparison. SMM decrease was associated with shorter survival in both manual and automated assessment (n = 78/280, HR 1.36 [95% CI 1.03 to 1.80] and n = 89/280, HR 1.38 [95% CI 1.05 to 1.81]). Occult SMM loss was associated with shorter survival in manual assessment, but not significantly in automated assessment (n = 44/263, HR 1.43 [95% CI 1.01 to 2.03] and n = 51/2639, HR 1.23 [95% CI 0.87 to 1.74]).

CONCLUSION

Deep-learning based assessment of SMM at L3 shows reliable performance, enabling the use of CT measures to guide clinical decision making. Implementation in clinical practice helps to identify patients with low muscle mass or (occult) SMM loss who may benefit from lifestyle interventions.

Understanding Secondary Sarcopenia Development in Young Adults Using Pig Model with Chronic Pancreatitis

Chronic pancreatitis (CP) in young individuals may lead to disease-related secondary sarcopenia (SSARC), characterized by muscle loss and systemic inflammation. In this study, CP was induced in young pigs, and serum levels of key hormones, muscle fiber diameters in various muscles, and the mRNA expression of genes related to oxidative stress and programmed cell death were assessed. A decrease in muscle fiber diameters was observed in SSARC pigs, particularly in the longissimus and diaphragm muscles. Hormonal analysis revealed alterations in dehydroepiandrosterone, testosterone, oxytocin, myostatin, and cortisol levels, indicating a distinct hormonal response in SSARC pigs compared to controls. Oxytocin levels in SSARC pigs were significantly lower and myostatin levels higher. Additionally, changes in the expression of catalase (CAT), caspase 8 (CASP8), B-cell lymphoma 2 (BCL2), and BCL2-associated X protein (BAX) mRNA suggested a downregulation of oxidative stress response and apoptosis regulation. A reduced BAX/BCL2 ratio in SSARC pigs implied potential caspase-independent cell death pathways. The findings highlight the complex interplay between hormonal changes and muscle degradation in SSARC, underscoring the need for further research into the apoptotic and inflammatory pathways involved in muscle changes due to chronic organ inflammation in young individuals.

Sarcopenic obesity and health outcomes: An umbrella review of systematic reviews with meta-analysis

Many studies support the idea that sarcopenic obesity (SO) could be considered a potential risk factor for negative health outcomes. These results have been inconsistent, and no umbrella reviews exist regarding this topic. Several databases until November 2023 were searched for systematic reviews with meta-analysis of observational studies (cross-sectional, case-control and prospective). For each association, random-effects summary effect sizes with correspondent 95% confidence intervals (CIs) were evaluated using the GRADE tool. Among the 213 papers initially screened, nine systematic reviews with meta-analysis were included, for a total of 384 710 participants. In cross-sectional and case-control studies, 30 different outcomes were analysed, and 18 were statistically significant. In any population addressed in cross-sectional and case-control studies, compared with non-SO, SO increased the prevalence of cognitive impairment (k = 3; odds ratio [OR] = 3.46; 95% CI: 2.24-5.32; high certainty of evidence), coronary artery disease (k = 2; OR = 2.48; 95% CI: 1.85-3.31) and dyslipidaemia (k = 3; OR = 2.50; 95% CI: 1.51-4.15). When compared with sarcopenia or obesity, the results were conflicting. In prospective studies, the association between SO-compared with non-SO-and other negative outcomes was supported by low/very low certainty of evidence and limited to a few conditions. Besides, no comparison with sarcopenia or obesity was provided. Finally, only a few studies have considered muscle function/physical performance in the diagnostic workup. SO could be considered a risk factor only for a few conditions, with the literature mainly based on cross-sectional and case-control studies. Future studies with clear definitions of SO are needed for quantifying the importance of SO-particularly when compared with the presence of only sarcopenia or obesity-and the weight of muscle function/physical performance in its definition.

Osteosarcopenia increases the risk of mortality: a systematic review and meta-analysis of prospective observational studies

BACKGROUND & AIMS

Osteosarcopenia is a recently recognized geriatric syndrome. The association between osteosarcopenia and mortality risk is still largely underexplored. In this systematic review with meta-analysis of prospective cohort studies, we aimed to explore whether osteosarcopenia could be associated with a higher mortality risk.

METHODS

Several databases were searched from the inception to 16th February 2024 for prospective cohort studies dealing with osteosarcopenia and mortality. We calculated the mortality risk in osteosarcopenia vs. controls using the most adjusted estimate available and summarized the data as risk ratios (RRs) with their 95% confidence intervals (CIs). A random-effect model was considered for all analyses.

RESULTS

Among 231 studies initially considered, nine articles were included after exclusions for a total of 14,429 participants (mean age: 70 years; 64.5% females). The weighted prevalence of osteosarcopenia was 12.72%. Over a mean follow-up of 6.6 years and after adjusting for a mean of four covariates, osteosarcopenia was associated with approximately 53% increased risk of mortality (RR: 1.53; 95% CI: 1.28-1.78). After accounting for publication bias, the re-calculated RR was 1.48 (95%CI: 1.23-1.72). The quality of the studies was generally good, as determined by the Newcastle Ottawa Scale.

CONCLUSIONS

Osteosarcopenia was significantly linked with an increased risk of mortality in older people, indicating the need to consider the presence of osteoporosis in patients with sarcopenia, and vice versa, since the combination of these two conditions typical of older people may lead to further complications, such as mortality.

Different roles of circulating and intramuscular GDF15 as markers of skeletal muscle health

Introduction

Growth Differentiation Factor 15 (GDF15) is a mitokine expressed in response to various stresses whose circulating levels increase with age and are associated with numerous pathological conditions, including muscle wasting and sarcopenia. However, the use of circulating GDF15 (c-GDF15) as a biomarker of sarcopenia is still debated. Moreover, the role of GDF15 intracellular precursor, pro-GDF15, in human skeletal muscle (SM-GDF15) is not totally understood. In order to clarify these points, the association of both forms of GDF15 with parameters of muscle strength, body composition, metabolism and inflammation was investigated.

Methods

the levels of c-GDF15 and SM-GDF15 were evaluated in plasma and muscle biopsies, respectively, of healthy subjects (HS) and patients with lower limb mobility impairment (LLMI), either young (<40 years-old) or old (>70 years-old). Other parameters included in the analysis were Isometric Quadriceps Strength (IQS), BMI, lean and fat mass percentage, Vastus lateralis thickness, as well as circulating levels of Adiponectin, Leptin, Resistin, IGF-1, Insulin, IL6, IL15 and c-PLIN2. Principal Component Analysis (PCA), Canonical Discriminant Analysis (CDA) and Receiving Operating Characteristics (ROC) analysis were performed.

Results

c-GDF15 but not SM-GDF15 levels resulted associated with decreased IQS and IGF-1 levels in both HS and LLMI, while only in LLMI associated with increased levels of Resistin. Moreover, in LLMI both c-GDF15 and SM-GDF15 levels were associated with IL-6 levels, but interestingly SM-GDF15 is lower in LLMI with respect to HS. Furthermore, a discrimination of the four groups of subjects based on these parameters was possible with PCA and CDA. In particular HS, LLMI over 70 years or under 40 years of age were discriminated based on SM-GDF15, c-GDF15 and Insulin levels, respectively.

Conclusion

our data support the idea that c-GDF15 level could be used as a biomarker of decreased muscle mass and strength. Moreover, it is suggested that c-GDF15 has a different diagnostic significance with respect to SM-GDF15, which is likely linked to a healthy and active state.

Definition and evolution of the concept of sarcopenia

Sarcopenia and dynapenia are two terms associated with ageing that respectively define the loss of muscle mass and strength. In 2018, the European Working Group on Sarcopenia in Older People (EWGSOP) introduced the EWGSOP2 diagnostic algorithm for sarcopenia, which integrates both concepts. It consists of 4 sequential steps: screening for sarcopenia, examination of muscle strength, assessment of muscle mass and physical performance; depending on these last 3 aspects sarcopenia is categorised as probable, confirmed, and severe respectively. In the absence of validation of the EWGSOP2 algorithm in various clinical contexts, its use in haemodialysis poses several limitations: (a) low sensitivity of the screening, (b) the techniques that assess muscle mass are not very accessible, reliable, or safe in routine clinical care, (c) the sequential use of the magnitudes that assess dynapenia and muscle mass do not seem to adequately reflect the muscular pathology of the elderly person on dialysis. We reflect on the definition of sarcopenia and the use of more precise terms such as "myopenia" (replacing the classic concept of sarcopenia to designate loss of muscle mass), dynapenia and kratopenia. Prospective evaluation of EWGSOP2 and its comparison with alternatives (i.e. assessment of kratopenia and dynapenia only; steps 2 and 4) is proposed in terms of its applicability in clinical routine, resource consumption, identification of at-risk individuals and impact on events.

Three-Year Mortality of Older Hospitalized Patients with Osteosarcopenia: Data from the OsteoSys Study

Osteosarcopenia, the concurrent presence of sarcopenia and osteopenia/osteoporosis, poses a significant health risk to older adults, yet its impact on clinical outcomes is not fully understood. The aim of this prospective, longitudinal multicentre study was to examine the impact of osteosarcopenia on 3-year mortality and unplanned hospitalizations among 572 older hospitalized patients (mean age 75.1 ± 10.8 years, 78% female). Sarcopenia and low bone mineral density (BMD) were evaluated using Dual Energy X-ray Absorptiometry and the European Working Group on Sarcopenia in Older People (EWGSOP2) and WHO criteria, respectively. Among participants, 76% had low BMD, 9% were sarcopenic, and 8% had osteosarcopenia. Individuals with osteosarcopenia experienced a significantly higher rate of mortality (46%, p < 001) and unplanned hospitalization (86%, p < 001) compared to those without this condition. Moreover, "healthy" subjects-those without sarcopenia or low BMD-showed markedly lower 3-year mortality (9%, p < 001) and less unplanned hospitalization (53%, p < 001). The presence of osteosarcopenia (p = 0.009) increased the 3-year mortality risk by 30% over sarcopenia alone and by 8% over low BMD alone, underscoring the severe health implications of concurrent muscle and bone deterioration. This study highlights the substantial impact of osteosarcopenia on mortality among older adults, emphasizing the need for targeted diagnostic and therapeutic strategies.

Comparison between Discrete Multi-Wavelength Near-Infrared Spectroscopy and Bioelectrical Impedance Analysis in the Assessment of Muscle Mass for Community-Dwelling Older People

(1) Background: This study evaluated the clinical implications of a new measurement technique for muscle mass using discrete multi-wavelength near-infrared spectroscopy (DMW-NIRS) compared with multifrequency bioelectrical impedance analysis (BIA) in older adults. (2) Methods: In a cross-sectional study involving 91 participants aged 65 years, the agreement of total lean mass for each measurement was assessed using the intraclass correlation coefficient (ICC) and Pearson's correlation analysis. The study was conducted at a university hospital from 10 July 2023 to 1 November 2023. (3) Results: A total of 45 men (mean age, 74.1) and 46 women (mean age, 73.6) were analyzed. In the comparisons of total lean mass between DMW-NIRS and BIA, ICC (2.1) was 0.943 and Cronbach's α coefficient was 0.949 (p < 0.001). Across all segments of lean mass, we found excellent agreement with the ICCs (>0.90) and acceptable values of the correlation coefficients (>0.6) between DMW-NIRS and BIA. (4) Conclusions: This study confirmed agreement in the measurements of muscle mass between portable devices using DMW-NIRS and BIA among community-dwelling older adults. A simple screening of muscle mass in a home setting would help to detect early decreases in muscle mass.

Streptococcal quorum sensing peptide CSP-7 contributes to muscle inflammation and wasting

Muscle wasting diseases, such as cancer cachexia and age-associated sarcopenia, have a profound and detrimental impact on functional independence, quality of life, and survival. Our understanding of the underlying mechanisms is currently limited, which has significantly hindered the development of targeted therapies. In this study, we explored the possibility that the streptococcal quorum sensing peptide Competence Stimulating Peptide 7 (CSP-7) might be a previously unidentified contributor to clinical muscle wasting. We found that CSP-7 selectively triggers muscle cell inflammation in vitro, specifically the release of IL-6. Furthermore, we demonstrated that CSP-7 can traverse the gastrointestinal barrier in vitro and is present in the systemic circulation in humans in vivo. Importantly, CSP-7 was associated with a muscle wasting phenotype in mice in vivo. Overall, our findings provide new mechanistic insights into the pathophysiology of muscle inflammation and wasting.

Correlates of Skeletal Muscle Mass and Differences Between Novel Subtypes in Recent-Onset Diabetes

CONTEXT

Low skeletal muscle mass (SMM) is associated with long-standing diabetes but little is known about SMM in newly diagnosed diabetes.

OBJECTIVE

We aimed to identify correlates of SMM in recent-onset diabetes and to compare SMM between novel diabetes subtypes.

METHODS

SMM was normalized to body mass index (SMM/BMI) in 842 participants with known diabetes duration of less than 1 year from the German Diabetes Study (GDS). Cross-sectional associations between clinical variables, 79 biomarkers of inflammation, and SMM/BMI were assessed, and differences in SMM/BMI between novel diabetes subtypes were analyzed with different degrees of adjustment for confounders.

RESULTS

Male sex and physical activity were positively associated with SMM/BMI, whereas associations of age, BMI, glycated hemoglobin A1c, homeostatic model assessment for β-cell function, and estimated glomerular filtration rate with SMM/BMI were inverse (all P < .05; model r2 = 0.82). Twenty-three biomarkers of inflammation showed correlations with SMM/BMI after adjustment for sex and multiple testing (all P < .0006), but BMI largely explained these correlations. In a sex-adjusted analysis, individuals with severe autoimmune diabetes had a higher SMM/BMI whereas individuals with severe insulin-resistant diabetes and mild obesity-related diabetes had a lower SMM/BMI than all other subtypes combined. However, differences were attenuated after adjustment for the clustering variables.

CONCLUSION

SMM/BMI differs between diabetes subtypes and may contribute to subtype differences in disease progression. Of note, clinical variables rather than biomarkers of inflammation explain most of the variation in SMM/BMI.

Mitochondrial Quantity and Quality in Age-Related Sarcopenia

Sarcopenia, the age-associated decline in skeletal muscle mass and strength, is a condition with a complex pathophysiology. Among the factors underlying the development of sarcopenia are the progressive demise of motor neurons, the transition from fast to slow myosin isoform (type II to type I fiber switch), and the decrease in satellite cell number and function. Mitochondrial dysfunction has been indicated as a key contributor to skeletal myocyte decline and loss of physical performance with aging. Several systems have been implicated in the regulation of muscle plasticity and trophism such as the fine-tuned and complex regulation between the stimulator of protein synthesis, mechanistic target of rapamycin (mTOR), and the inhibitor of mTOR, AMP-activated protein kinase (AMPK), that promotes muscle catabolism. Here, we provide an overview of the molecular mechanisms linking mitochondrial signaling and quality with muscle homeostasis and performance and discuss the main pathways elicited by their imbalance during age-related muscle wasting. We also discuss lifestyle interventions (i.e., physical exercise and nutrition) that may be exploited to preserve mitochondrial function in the aged muscle. Finally, we illustrate the emerging possibility of rescuing muscle tissue homeostasis through mitochondrial transplantation.

Bibliometric and scientometric analysis on biomarkers and molecular mechanisms for physical frailty and sarcopenia

Introduction

The influence of physical frailty and sarcopenia (PFS) on the well-being of older people and continuous pressure on the healthcare systems has prompted a research on the pathophysiology and molecular mechanisms of these conditions. Nonetheless some biomarkers have been suggested as potential markers for PFS none of them have been shown to highlight the complex nature of PFS, which reveals that there is a need for an understanding of the possible biomarker candidates. The aim of this study was to identify the current research hotspots, status, and trends in the field of biomarkers and molecular mechanisms for PFS.

Methods

The bibliometric and scientometric analyses were performed using VOSviewer (version 1.6.18) and open source software platform Cytoscape v.3.9 (for visualizing and constructing a network of keywords). Data of publications (from 1997 to 2023) related to biomarkers and molecular mechanisms of PFS were obtained (in May 2023) from the database of Science Citation Index Expanded of Web of Science, Scopus, and PubMed. The keywords obtained from the Scopus database were used to perform a meaningful keyword analysis. A network of keyword relationships was build using Cytoscape.

Results

In this study, we present biomarker keywords for PFS in relation to other keywords potentially designating processes and mechanisms and reveal the biomarker identities and current contexts in which these biomarker identities are discussed.

Conclusions

Over recent years, scientific interest in the field of PFS has increased and focused on the inflammatory process and probably will be concentrated on myokines (such as cytokines and small proteins) that are synthetized and released by skeletal muscles in response to physical activity. Moreover, proteomic and genetic markers are deeply involved in PFS.

The prevalence, risk factors and clinical implications of dehydration in older patients: a cross-sectional study

OBJECTIVES

Adequate hydration is essential for the maintenance of physiological functions. Older adults may not be able to maintain adequate hydration, which is often not recognized. Our aim was to investigate the prevalence, risk factors and clinical implications of dehydration in older adults.

METHODS

This cross-sectional study included 964 older adults in one geriatric outpatient clinic in Turkey. Dehydration was defined as a calculated [1,86 × (Na+K)+1,15×glucose+urea +14] plasma osmolarity of ≥ 295 mOsm/L. Clinical characteristics and measures of comprehensive geriatric assessments of patients with dehydration and normohydration were compared. Predictors of dehydration were assessed using logistic regression analysis.

RESULTS

Mean age was 79.9 ± 7.7 years, (71.7% female). The prevalence of dehydration was 31%. Female patients, diabetes mellitus (DM), chronic renal failure (CKD), a higher risk of falling (based on Timed Up and Go test), probable sarcopenia, dependence based on basic and instrumental daily living activities (BADL and IADL) were more common in the dehydrated group (p < 0.05). After adjusting for age and gender, dependency on BADL and IADL, the risk of falling were still higher in the dehydrated group (p < 0.05). There were significant relationships between dehydration and risk of falling (OR 1.38, 95% CI 1.00-1.90; p < 0.05), after adjustment for age, gender, DM, CKD.

CONCLUSION

Dehydration is common among older adults and is associated with a dependency, probable sarcopenia, and an increased risk of falling. Screening for dehydration and taking preventive measures may be beneficial in avoiding the negative consequences associated with dehydration.

Quality of life in sarcopenia measured with the SarQoL questionnaire: A meta-analysis of individual patient data

Age-related sarcopenia, resulting from a gradual loss in skeletal muscle mass and strength, is pivotal to the increased prevalence of functional limitation among the older adult community. The purpose of this meta-analysis of individual patient data is to investigate the difference in health-related quality of life between sarcopenic individuals and those without the condition using the Sarcopenia Quality of Life (SarQoL) questionnaire. A protocol was published on PROSPERO. Multiple databases and the grey literature were searched until March 2023 for studies reporting quality of life assessed with the SarQoL for patients with and without sarcopenia. Two researchers conducted the systematic review independently. A two-stage meta-analysis was performed. First, crude (mean difference) and adjusted (beta coefficient) effect sizes were calculated within each database; then, a random effect meta-analysis was applied to pool them. Heterogeneity was measured using the Q-test and I2 value. Subgroup analyses were performed to investigate the source of potential heterogeneity. The strength of evidence of this association was assessed using GRADE. From the 413 studies identified, 32 were eventually included, of which 10 were unpublished data studies. Sarcopenic participants displayed significantly reduced health-related quality of life compared with non-sarcopenic individuals (mean difference = -12.32; 95 % CI = [-15.27; -9.37]). The model revealed significant heterogeneity. Subgroup analyses revealed a substantial impact of regions, clinical settings, and diagnostic criteria on the difference in health-related quality of life between sarcopenic and non-sarcopenic individuals. The level of evidence was moderate. This meta-analysis of individual patient data suggested that sarcopenia is associated with lower health-related quality of life measured with SarQoL.

Prevalence of sarcopenia in Africa: a systematic review and meta-analysis of observational studies

BACKGROUND

Existing literature suggests that sarcopenia is a highly prevalent condition in older people. However, most studies to date reporting data on its prevalence have been mainly carried out in Western countries, while data on sarcopenia in Africa is scarce. With this systematic review and meta-analysis, we aimed to determine the prevalence of sarcopenia in African countries and to explore potential factors that could explain higher or lower prevalence of this condition in Africa.

METHODS

Major databases for studies reporting data on sarcopenia in African countries were searched from inception to June 2023. We conducted a meta-analysis of the prevalence [and 95% confidence intervals (95% CIs)] of sarcopenia in Africa, applying a random effect model. Several sensitivity and meta-regression analyses were run.

RESULTS

Among 147 articles initially screened, six articles (with seven cohorts) including a total of 10,656 participants were included. Mean age of participants was 66.9 years, and the majority were female (58.1%). The weighted prevalence of sarcopenia in the selected countries of Africa was 25.72% (95%CI: 18.90-32.55). This outcome was characterized by a high heterogeneity (I2 = 99%) and by publication bias. Among the factors investigated, sarcopenia was lower when assessed using only one anthropometric measure, or in South Africa.

CONCLUSION

Sarcopenia is a prevalent condition in Africa and thus research regarding this topic is a public health priority. Future studies that cover African countries for which data are not available and using standardized criteria are needed.

Effect of Resistance Exercise on Body Composition and Functional Capacity in Older Women with Sarcopenic Obesity-A Systematic Review with Narrative Synthesis

BACKGROUND

Resistance exercise has shown effectiveness in reducing various risk factors related to sarcopenic obesity (SO) compared to other types of exercise, e.g., aerobic exercise.

OBJECTIVE

This systematic review evaluates the effect of resistance exercise on body composition, muscular strength, and functional capacity among older women with sarcopenic obesity aged ≥ 60 years.

METHODS

This systematic review is registered on PROSPERO (registration No. CRD42023394603) and follows the PRISMA guidelines. The following electronic databases were used to search the literature: Pedro, Cochrane Central Register of Controlled Trials, Embase, PubMed, and Web of Science. We included only RCTs that investigated the effect of resistance exercise on body composition and functional capacity. Two independent reviewers conducted the process of study selection and data extraction.

RESULTS

The search strategy retrieved 687 results. One hundred and twenty-six records were deleted as duplicates. Consequently, 534 studies were excluded after the title/abstract assessment. After further detailed evaluation of twenty-seven full texts, seven RCTs were included; all the RCTs examined the isolated effect of resistance exercise in women with sarcopenic obesity. The included studies comprised 306 participants, with an average age of 64 to 72 years. We noticed a trend of improvement in the included studies among the intervention groups compared to the control groups among the different outcomes. The study protocol was inconsistent for the intervention settings, duration, and outcomes. Including a modest number of trials made it impossible to perform data meta-analysis.

CONCLUSIONS

Heterogeneity among studies regarding training protocols and the outcome measures reported limited robust conclusions. Still, resistance exercise intervention can improve body composition and functional capacity among elderly women with sarcopenic obesity.

Sit-to-Stand Video Analysis-Based App for Diagnosing Sarcopenia and Its Relationship With Health-Related Risk Factors and Frailty in Community-Dwelling Older Adults: Diagnostic Accuracy Study

BACKGROUND

Probable sarcopenia is determined by a reduction in muscle strength assessed with the handgrip strength test or 5 times sit-to-stand test, and it is confirmed with a reduction in muscle quantity determined by dual-energy X-ray absorptiometry or bioelectrical impedance analysis. However, these parameters are not implemented in clinical practice mainly due to a lack of equipment and time constraints. Nowadays, the technical innovations incorporated in most smartphone devices, such as high-speed video cameras, provide the opportunity to develop specific smartphone apps for measuring kinematic parameters related with sarcopenia during a simple sit-to-stand transition.

OBJECTIVE

We aimed to create and validate a sit-to-stand video analysis-based app for diagnosing sarcopenia in community-dwelling older adults and to analyze its construct validity with health-related risk factors and frailty.

METHODS

A total of 686 community-dwelling older adults (median age: 72 years; 59.2% [406/686] female) were recruited from elderly social centers. The index test was a sit-to-stand video analysis-based app using muscle power and calf circumference as proxies of muscle strength and muscle quantity, respectively. The reference standard was obtained by different combinations of muscle strength (handgrip strength or 5 times sit-to-stand test result) and muscle quantity (appendicular skeletal mass or skeletal muscle index) as recommended by the European Working Group on Sarcopenia in Older People-2 (EWGSOP2). Sensitivity, specificity, positive and negative predictive values, and area under the curve (AUC) of the receiver operating characteristic curve were calculated to determine the diagnostic accuracy of the app. Construct validity was evaluated using logistic regression to identify the risks associated with health-related outcomes and frailty (Fried phenotype) among those individuals who were classified as having sarcopenia by the index test.

RESULTS

Sarcopenia prevalence varied from 2% to 11% according to the different combinations proposed by the EWGSOP2 guideline. Sensitivity, specificity, and AUC were 70%-83.3%, 77%-94.9%, and 80.5%-87.1%, respectively, depending on the diagnostic criteria used. Likewise, positive and negative predictive values were 10.6%-43.6% and 92.2%-99.4%, respectively. These results proved that the app was reliable to rule out the disease. Moreover, those individuals who were diagnosed with sarcopenia according to the index test showed more odds of having health-related adverse outcomes and frailty compared to their respective counterparts, regardless of the definition proposed by the EWGSOP2.

CONCLUSIONS

The app showed good diagnostic performance for detecting sarcopenia in well-functioning Spanish community-dwelling older adults. Individuals with sarcopenia diagnosed by the app showed more odds of having health-related risk factors and frailty compared to their respective counterparts. These results highlight the potential use of this app in clinical settings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05148351; https://clinicaltrials.gov/study/NCT05148351.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.3390/s22166010.

Sarcopenia and Chronic Pain in the Elderly: A Systematic Review and Meta-Analysis

Objective

Sarcopenia and chronic pain are prevalent among older adults, and despite numerous studies, the potential epidemiological link between the two conditions remains a topic of controversy. Therefore, we performed a comprehensive systematic review and meta-analysis to assess the relationship between chronic pain and sarcopenia in the elderly.

Methods

EMBASE, Web of Science, PubMed, and the Cochrane Library were searched through 22 March 2023 with additional manual searches of reference lists of included studies and relevant reviews. We used a random effects model to conduct the meta-analysis and evaluated heterogeneity across studies with Cochran's Q statistic and I2. Subgroup analyses were conducted based on income level, diagnostic criteria for sarcopenia, and pain site.

Results

17 observational studies (33,600 participants, 49% female) were included, of which 6 articles were retrieved for narrative review. The pooled prevalence of sarcopenia and the pooled odds ratios (OR) between chronic pain and sarcopenia were extracted from the remaining 11 studies. The pooled prevalence of sarcopenia among older adults suffering from chronic pain was 0.11 (95% CI, 0.08-0.18). Our analysis revealed a statistically significant positive association between chronic pain and an increased risk of sarcopenia, yielding a pooled OR of 1.52 (95% CI, 1.31-1.76). Furthermore, our subgroup analysis demonstrated that the low-income countries group showed a stronger association (OR, 1.73; 95% CI, 1.54-1.95) between chronic pain and sarcopenia than the high-income countries group (OR, 1.38; 95% CI, 1.20-1.60).

Conclusion

Older adults with chronic pain have a significantly higher prevalence of sarcopenia and risk of developing sarcopenia compared to those without pain. These findings highlight the importance of prioritizing the assessment and early detection of chronic pain in older people, as well as implementing proactive intervention measures in clinical practice. In addition, our results suggest that older people with chronic pain should be actively screened for sarcopenia.

Prospero Registration Number

CRD42021239807.

Deep-learning model for predicting physical fitness in possible sarcopenia: analysis of the Korean physical fitness award from 2010 to 2023

Introduction

Physical fitness is regarded as a significant indicator of sarcopenia. This study aimed to develop and evaluate a deep-learning model for predicting the decline in physical fitness due to sarcopenia in individuals with potential sarcopenia.

Methods

This study used the 2010-2023 Korean National Physical Fitness Award data. The data comprised exercise- and health-related measurements in Koreans aged >65 years and included body composition and physical fitness variables. Appendicular muscle mass (ASM) was calculated as ASM/height2 to define normal and possible sarcopenia. The deep-learning model was created with EarlyStopping and ModelCheckpoint to prevent overfitting and was evaluated using stratified k-fold cross-validation (k = 5). The model was trained and tested using training data and validation data from each fold. The model's performance was assessed using a confusion matrix, receiver operating characteristic curve, and area under the curve. The average performance metrics obtained from each cross-validation were determined. For the analysis of feature importance, SHAP, permutation feature importance, and LIME were employed as model-agnostic explanation methods.

Results

The deep-learning model proved effective in distinguishing from sarcopenia, with an accuracy of 87.55%, precision of 85.57%, recall of 90.34%, and F1 score of 87.89%. Waist circumference (WC, cm), absolute grip strength (kg), and body fat (BF, %) had an influence on the model output. SHAP, LIME, and permutation feature importance analyses revealed that WC and absolute grip strength were the most important variables. WC, figure-of-8 walk, BF, timed up-and-go, and sit-and-reach emerged as key factors for predicting possible sarcopenia.

Conclusion

The deep-learning model showed high accuracy and recall with respect to possible sarcopenia prediction. Considering the need for the development of a more detailed and accurate sarcopenia prediction model, the study findings hold promise for enhancing sarcopenia prediction using deep learning.

Incident sarcopenia in hospitalized older people: A systematic review

Hospitalization has been associated with the development of sarcopenia. This study aimed to examine the new incidences of hospital sarcopenia, associated risk factors and health outcomes, as defined by internationally recognized diagnostic criteria in hospitalized older people. Pre-defined search terms were run through five databases. Six studies that assessed sarcopenia on two separate time points during hospitalization on older inpatients were included. Prevalence of sarcopenia varied from 14.1% to 55% depending on diagnostic criteria and cut-off points used. New sarcopenia occurred between 12% to 38.7% patients following hospitalization. Risk factors were older age, longer duration of bed rest, lower baseline body mass index, cognitive impairment and activities of daily living disability. None of the studies reported health outcomes associated with newly developed sarcopenia in hospital.

Measuring health-related quality of life in sarcopenia: summary of the SarQoL psychometric properties

Patient perspectives are now widely recognized as a key element in the evaluation of health interventions. Therefore, the provision of specific and validated Patient Reported Outcome Measures that emphasize the lived experience of patients suffering from specific diseases is very important. In the field of sarcopenia, the only validated specific health-related quality of life (HRQoL) instrument available is the Sarcopenia Quality of Life questionnaire (SarQoL). This self-administrated HRQoL questionnaire, developed in 2015, consists of 55 items arranged into 22 questions and has currently been translated into 35 languages. Nineteen validation studies performed on SarQoL have consensually confirmed the capacity of SarQoL to detect difference in HRQoL between older people with and without sarcopenia, its reliability and its validity. Two further observational studies have also indicated its responsiveness to change. A short form SarQoL, including only 14 items has further been developed and validated to reduce the potential burden of administration. Research on the psychometric properties of SarQoL questionnaire is still encouraged as the responsiveness to change of SarQoL has not yet been measured in the context of interventional studies, as limited prospective data currently exist and as there is still not cut-off score to define a low HRQoL. In addition, SarQoL has mainly been used in community-dwelling older individuals with sarcopenia and would benefit to be studied in other types of populations. This review aims to provide to researchers, clinicians, regulators, pharmaceutical industries and other stakeholders a clear summary of comprehensive evidence on the SarQoL questionnaire published up to January 2023Query.

"Diet for the prevention and management of sarcopenia"

Sarcopenia is a geriatric condition characterized by a progressive loss of skeletal muscle mass and strength, with an increased risk of adverse health outcomes (e.g., falls, disability, institutionalization, reduced quality of life, mortality). Pharmacological remedies are currently unavailable for preventing the development of sarcopenia, halting its progression, or impeding its negative health outcomes. The most effective strategies to contrast sarcopenia rely on the adoption of healthier lifestyle behaviors, including adherence to high-quality diets and regular physical activity. In this review, the role of nutrition in the prevention and management of sarcopenia is summarized. Special attention is given to current "blockbuster" dietary regimes and agents used to counteract age-related muscle wasting, together with their putative mechanisms of action. Issues related to the design and implementation of effective nutritional strategies are discussed, with a focus on unanswered questions on the most appropriate timing of nutritional interventions to preserve muscle health and function into old age. A brief description is also provided on new technologies that can facilitate the development and implementation of personalized nutrition plans to contrast sarcopenia.

Pain Increases the Risk for Sarcopenia in Community-Dwelling Adults: Results From the English Longitudinal Study of Ageing

BACKGROUND

Pain and sarcopenia are common in older people. Cross-sectional studies have reported a significant association between these two conditions, but cohort studies exploring pain as a potential risk factor for sarcopenia are scarce. Given this background, the aim of the present work was to investigate the association between pain (and its severity) at baseline, and the incidence of sarcopenia over 10 years of follow-up in a large representative sample of the English older adult population.

METHODS

Pain was diagnosed using self-reported information and categorized as mild to severe pain at four sites (low back, hip, knee, and feet). Incident sarcopenia was defined as having low handgrip strength and low skeletal muscle mass during the follow-up period. The association between pain at baseline and incident sarcopenia was assessed using an adjusted logistic regression analysis, and reported as odds ratios (ORs) with their 95% confidence intervals (CIs).

RESULTS

The 4 102 participants without sarcopenia at baseline had a mean ± standard deviation age of 69.7 ± 7.2 years, and they were mainly male (55.6%). Pain was present in 35.3% of the sample. Over 10 years of follow-up, 13.9% of the participants developed sarcopenia. After adjusting for 12 potential confounders, people with pain reported a significantly higher risk of sarcopenia (OR = 1.46: 95% CI: 1.18-1.82). However, only severe pain was significantly associated with incident sarcopenia, without significant differences across the four sites assessed.

CONCLUSIONS

The presence of pain, particularly severe pain, was associated with a significantly higher risk of incident sarcopenia.

Association Between Pain and Sarcopenia Among Adults Aged ≥65 Years from Low- and Middle-Income Countries

BACKGROUND

Pain may increase the risk for sarcopenia, but existing literature is only from high-income countries, while the mediators of this association are largely unknown. Thus, we aimed to investigate the association between pain and sarcopenia using nationally representative samples of older adults from 6 low- and middle-income countries (LMICs), and to identify potential mediators.

METHODS

Cross-sectional data from the WHO Study on global AGEing and adult health (SAGE) were analyzed. Sarcopenia was defined as having low skeletal muscle mass and weak handgrip strength, while the presence and severity of pain in the last 30 days were self-reported. Multivariable logistic regression and mediation analyses were performed. The control variables included age, sex, education, wealth, and chronic conditions, while affect, sleep/energy, disability, social participation, sedentary behavior, and mobility were considered potential mediators.

RESULTS

Data on 14,585 adults aged ≥65 years were analyzed (mean [SD] age 72.6 [11.5] years; 55.0% females). Compared to no pain, mild, moderate, severe, and extreme pain were associated with 1.42 (95% confidence interval [CI] = 1.05-1.94), 1.43 (95%CI = 1.02-2.00), 1.92 (95%CI = 1.09-3.37), and 2.88 (95%CI = 1.10-7.54) times higher odds for sarcopenia, respectively. Disability (mediated percentage 18.0%), sedentary behavior (12.9%), and low mobility (56.1%) were significant mediators in the association between increasing levels of pain and sarcopenia.

CONCLUSIONS

Higher levels of pain were associated with higher odds for sarcopenia among adults aged ≥65 years in 6 LMICs. Disability, sedentary behavior, and mobility problems were identified as potential mediators. Targeting these factors in people with pain may decrease the future risk of sarcopenia onset, pending future longitudinal research.

Sarcopenia and health-related quality of life: A systematic review and meta-analysis

The decrease of physical abilities and functional decline that can be caused by musculoskeletal conditions such as sarcopenia, can lead to higher levels of dependency and disability. Therefore, it may influence patient reported outcome measures (PROM), such as the health-related quality of life (HRQoL). The purpose of this systematic review and meta-analysis is to provide a comprehensive overview of the relationship between sarcopenia and HRQoL. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed throughout the whole process of this work. A protocol was previously published on PROSPERO. The electronic databases MEDLINE, Scopus, Allied and Complementary Medicine (AMED), EMB Review - ACP Journal Club, EBM Review - Cochrane Central of Register of Controlled Trials and APA PsychInfo were searched until October 2022 for observational studies reporting a HRQoL assessment in both sarcopenic and non-sarcopenic individuals. Study selection and data extraction were carried out by two independent researchers. Meta-analysis was performed using a random effect model, reporting an overall standardized mean difference (SMD) and its 95% confidence interval (CI) between sarcopenic and non-sarcopenic individuals. Study quality was measured using the Newcastle-Ottawa Scale and the strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool. The search strategy identified 3725 references from which 43 observational studies were eligible and included in this meta-synthesis study. A significantly lower HRQoL was observed for sarcopenic individuals compared with non-sarcopenic ones (SMD -0.76; 95% CI -0.95; -0.57). Significant heterogeneity was associated with the model (I²  = 93%, Q test P-value <0.01). Subgroup analysis showed a higher effect size when using the specific questionnaire SarQoL compared with generic questionnaires (SMD -1.09; 95% CI -1.44; -0.74 with the SarQoL versus -0.49; 95% CI -0.63; -0.36 with generic tools; P-value for interaction <0.01). A greater difference of HRQoL between sarcopenic and non-sarcopenic was found for individuals residing in care homes compared with community-dwelling individuals (P-value for interaction <0.001). No differences were found between age groups, diagnostic techniques, and continents/regions. The level of evidence was rated as moderate using the GRADE assessment. This systematic review and meta-analysis combining 43 observational studies shows that HRQoL is significantly reduced in sarcopenic patients. The use of disease-specific HRQoL instruments may better discriminate sarcopenic patients with respect to their quality of life.

Relationship between sarcopenia and orthostatic blood pressure recovery in older falls clinic attendees

PURPOSE

Sarcopenia and delayed orthostatic blood pressure (BP) recovery are two disorders increasingly associated with adverse clinical outcomes in older adults. There may exist a pathophysiological link between the two via the skeletal muscle pump of the lower limbs. Previously in a large population-based study, we found an association between probable sarcopenia and orthostatic BP recovery. Here, we sought to determine the association between confirmed sarcopenia and orthostatic BP recovery in falls clinic attendees aged 50 years or over.

METHODS

One hundred and nine recruited patients (mean age 70 years, 58% women) underwent an active stand with non-invasive beat-to-beat haemodynamic monitoring. Hand grip strength and five-chair stands time were measured, and bioelectrical impedance analysis was performed. They were then classified as robust, probable sarcopenic or sarcopenic as per the European Working Group on Sarcopenia in Older People guidelines. Mixed effects models with linear splines were used to model the effect of sarcopenia status on orthostatic BP recovery, whilst controlling for potential confounders.

RESULTS

Probable sarcopenia was identified in 32% of the sample and sarcopenia in 15%. Both probable and confirmed sarcopenia were independently associated with an attenuated rate of recovery of both systolic and diastolic BP in the 10-20 s period after standing. Attenuation was larger for confirmed than probable sarcopenia (systolic BP β - 0.85 and - 0.59, respectively, P < 0.01; diastolic BP β - 0.65, - 0.45, P < 0.001).

CONCLUSION

Sarcopenia was independently associated with slower BP recovery during the early post-stand period. The potentially modifiable effect of the skeletal muscle pump in orthostatic haemodynamics requires further study.

Sarcopenia is associated with a greater risk of polypharmacy and number of medications: a systematic review and meta-analysis

Polypharmacy in older adults is associated with multiple negative consequences that may affect muscular function, independently from the presence of medical conditions. The aim of this systematic review and meta-analysis was to investigate the association of sarcopenia with polypharmacy and higher number of medications. A systematic literature search of observational studies using PubMed, Web of Science, Scopus and Cochrane Library databases was conducted from inception until June 2022. To determine if sarcopenia is associated with a higher risk of polypharmacy and increased number of medications, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42022337539). Twenty-nine studies were included in the systematic review and meta-analysis. Sarcopenia was associated with a higher prevalence of polypharmacy (odds ratio [OR]: 1.65, 95% confidence interval [CI] [1.23, 2.20], I2  = 84%, P < 0.01) and higher number of medications (mean difference: 1.39, 95% CI [0.59, 2.19], I2  = 95%, P < 0.01) compared with individuals without sarcopenia. Using meta-regression, a high variance was observed due to different populations (i.e., community-dwelling, nursing home residents, inpatients, outpatients) for both outcomes of polypharmacy (r = -0.338, SE = 0.1669, 95% CI [-0.67, -0.01], z = -2.03, P = 0.04) and number of medications (r = 0.589, SE = 0.2615, 95% CI [0.08, 1.10], z = 2.25, P = 0.02). This systematic review and meta-analysis reported a significantly increased risk of polypharmacy and higher number of medications in people with sarcopenia compared with individuals without this condition. Future research should clarify whether the specificity and number of medications is a direct contributor in accelerating the progression of muscle wasting and dysfunction contributing to sarcopenia in older adults.

Prevalence of Sarcopenia in Knee Osteoarthritis: A Systematic Review and Meta-Analysis

An association between knee osteoarthritis (OA) and sarcopenia has been proposed, but the evidence is controversial, with the recent literature showing disparate results. Therefore, we aimed to perform a systematic review and meta-analysis to evaluate the prevalence of sarcopenia in knee OA patients compared to people not affected by this condition. We searched several databases until 22 February 2022. The data regarding prevalence were summarized using odds ratios (ORs) with their 95% confidence intervals (CIs). Among the 504 papers initially screened, 4 were included for a total of 7495 participants with a mean age of 68.4 years, who were mainly females (72.4%). The prevalence of sarcopenia in people with knee OA was 45.2%, whilst, in the controls, it was 31.2%. Pooling the data of the studies included that the prevalence of sarcopenia in knee OA was more than two times higher than in the control group (OR = 2.07; 95%CI: 1.43-3.00; I2 = 85%). This outcome did not suffer any publication bias. However, after removing an outlier study, the recalculated OR was 1.88. In conclusion, the presence of sarcopenia in knee OA patients was high, affecting one person in every two persons and was higher than in the control groups included.

Identification and Characterization of Genomic Predictors of Sarcopenia and Sarcopenic Obesity Using UK Biobank Data

The substantial decline in skeletal muscle mass, strength, and gait speed is a sign of severe sarcopenia, which may partly depend on genetic risk factors. So far, hundreds of genome-wide significant single nucleotide polymorphisms (SNPs) associated with handgrip strength, lean mass and walking pace have been identified in the UK Biobank cohort; however, their pleiotropic effects on all three phenotypes have not been investigated. By combining summary statistics of genome-wide association studies (GWAS) of handgrip strength, lean mass and walking pace, we have identified 78 independent SNPs (from 73 loci) associated with all three traits with consistent effect directions. Of the 78 SNPs, 55 polymorphisms were also associated with body fat percentage and 25 polymorphisms with type 2 diabetes (T2D), indicating that sarcopenia, obesity and T2D share many common risk alleles. Follow-up bioinformatic analysis revealed that sarcopenia risk alleles were associated with tiredness, falls in the last year, neuroticism, alcohol intake frequency, smoking, time spent watching television, higher salt, white bread, and processed meat intake; whereas protective alleles were positively associated with bone mineral density, serum testosterone, IGF1, and 25-hydroxyvitamin D levels, height, intelligence, cognitive performance, educational attainment, income, physical activity, ground coffee drinking and healthier diet (muesli, cereal, wholemeal or wholegrain bread, potassium, magnesium, cheese, oily fish, protein, water, fruit, and vegetable intake). Furthermore, the literature data suggest that single-bout resistance exercise may induce significant changes in the expression of 26 of the 73 implicated genes in m. vastus lateralis, which may partly explain beneficial effects of strength training in the prevention and treatment of sarcopenia. In conclusion, we have identified and characterized 78 SNPs associated with sarcopenia and 55 SNPs with sarcopenic obesity in European-ancestry individuals from the UK Biobank.

Biochemical Markers of Musculoskeletal Health and Aging to be Assessed in Clinical Trials of Drugs Aiming at the Treatment of Sarcopenia: Consensus Paper from an Expert Group Meeting Organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the Centre Académique de Recherche et d'Expérimentation en Santé (CARES SPRL), Under the Auspices of the World Health Organization Collaborating Center for the Epidemiology of Musculoskeletal Conditions and Aging

In clinical trials, biochemical markers provide useful information on the drug's mode of action, therapeutic response and side effect monitoring and can act as surrogate endpoints. In pharmacological intervention development for sarcopenia management, there is an urgent need to identify biomarkers to measure in clinical trials and that could be used in the future in clinical practice. The objective of the current consensus paper is to provide a clear list of biochemical markers of musculoskeletal health and aging that can be recommended to be measured in Phase II and Phase III clinical trials evaluating new chemical entities for sarcopenia treatment. A working group of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) proposed classifying biochemical markers into 2 series: biochemical markers evaluating musculoskeletal status and biochemical markers evaluating causal factors. For series 1, the group agreed on 4 biochemical markers that should be assessed in Phase II or Phase III trials (i.e., Myostatin-Follistatin, Brain Derived Neurotrophic Factor, N-terminal Type III Procollagen and Serum Creatinine to Serum Cystatin C Ratio - or the Sarcopenia Index). For series 2, the group agreed on 6 biochemical markers that should be assessed in Phase II trials (i.e., the hormones insulin-like growth factor-1 (IGF-I), dehydroepiandrosterone sulphate, and cortisol, and the inflammatory markers C-reactive protein (CRP), interleukin-6 and tumor necrosis factor-α), and 2 in Phase III trials (i.e., IGF-I and CRP). The group also proposed optional biochemical markers that may provide insights into the mode of action of pharmacological therapies. Further research and development of new methods for biochemical marker assays may lead to the evolution of these recommendations.

A systematic review and meta-analysis of the prevalence and correlation of mild cognitive impairment in sarcopenia

Sarcopenia is a progressive skeletal muscle disorder involving the loss of muscle mass and function, associated with an increased risk of disability and frailty. Though its prevalence in dementia has been studied, its occurrence in mild cognitive impairment (MCI) has not been well established. As MCI is often a prelude to dementia, our study aims to investigate the prevalence of MCI among individuals with sarcopenia and to also ascertain whether sarcopenia is independently associated with MCI. The Cochrane Library, PubMed, Ovid, Embase and Web of Science were systematically searched for articles on MCI and/or sarcopenia published from inception to 1 February 2022. We reviewed the available literature on the number of individuals with MCI and/or sarcopenia and calculated odds ratios (ORs) of sarcopenia in MCI and MCI in sarcopenia, respectively. Statistical analyses were performed using the meta package in Stata, Version 12.0. A total of 13 studies and 27 428 patients were included in our analysis. The pooled prevalence of MCI in participants with sarcopenia was 20.5% (95% confidence interval [CI]: 0.140-0.269) in a total sample of 2923 cases with a high level of heterogeneity (P < 0.001; I²  = 95.4%). The overall prevalence of sarcopenia with MCI was 9.1% (95% CI: 0.047-0.134, P < 0.001; I²  = 93.0%). For overall ORs, there were 23 364 subjects with a mean age of 73 years; the overall adjusted OR between MCI and sarcopenia was 1.46 (95% CI: 1.31-1.62). Slight heterogeneity in both adjusted ORs (P = 0.46; I²  = 0%) was noted across the studies. The prevalence of MCI is relatively high in patients with sarcopenia, and sarcopenia may be a risk factor for MCI.

Prevalência e características associadas à sarcopenia em pessoas idosas: estudo transversal

RESUMO Objetivos: identificar a prevalência e as características associadas à sarcopenia em pessoas idosas de Unidades de Atenção Primária à Saúde. Métodos: estudo transversal, com 384 pessoas idosas. Para avaliação de sarcopenia, mediu-se: força e massa muscular, desempenho físico. Classificaram se pessoas idosas com: sarcopenia provável; sarcopenia; e sarcopenia grave. Analisou-se com teste de qui quadrado e método de regressão logística multinomial. Resultados: a prevalência de provável sarcopenia foi de 25,52%; sarcopenia, 11,98%; e sarcopenia grave, 9,90%. Homens são 1,75 vez mais prevalentes em indivíduos com provável sarcopenia; osteoporose é 2,16 vezes mais prevalente na sarcopenia grave; polifarmácia, 1,57 vez mais prevalente na provável sarcopenia; circunferência da panturrilha menor que 31 cm é 2,24 vezes mais prevalente na sarcopenia e 2,19 vezes na sarcopenia grave. Conclusões: houve maior prevalência de provável sarcopenia, e as características associadas à sarcopenia foram: sexo, osteoporose, polifarmácia, sobrepeso, obesidade e circunferência da panturrilha.

Prevalence of characteristics associated with sarcopenia in elders: a cross-sectional study

Objectives:

to identify the prevalence and characteristics associated with sarcopenia in elders in Primary Health Care Units.

Methods:

cross-sectional study with 384 elders. To evaluate sarcopenia, we measured: strength and muscle mass, and physical performance. The elderly were classified as having: probable sarcopenia; sarcopenia; or severe sarcopenia. The chi-squared test and the multinomial logistic regression method were used.

Results:

the prevalence of probable sarcopenia was 25.52%; of sarcopenia, 11.98%; and of severe sarcopenia, 9.90%. Probable sarcopenia is 1.75 times more prevalent in men; osteoporosis is 2.16 times more prevalent in people with severe sarcopenia; polypharmacy is 1.57 times more likely in individuals with probable sarcopenia; and calf circumference below 31 cm is 2.24 times more likely in patients with sarcopenia and 2.19 times more likely in patients with severe sarcopenia.

Conclusions:

the highest prevalence was of probable sarcopenia, and the characteristics associated with sarcopenia were sex, osteoporosis, polypharmacy, overweight, obesity, and calf circumference.

Ultrasonographic monitoring of feline epaxial muscle height as part of an annual wellness examination to assess for the development of sarcopenia

OBJECTIVES

The aim of this study was to determine if epaxial muscle height (EMH) could be reliably incorporated into annual routine wellness screenings, and also determine its relationship to age, body condition score (BCS), subjective muscle assessment (SMA), breed and sex in mature cats.

METHODS

EMH was determined independently by three observers from ultrasonographic examinations - collected by an additional trained individual - of cats enrolled at the Feline Healthy Ageing Clinic, University of Liverpool, UK. Age, body weight, BCS and SMA data were also collected.

RESULTS

A total of 92 cats were included, 35 of which had repeat ultrasonographic examinations 12 months apart. Enrolled cats were a median age of 8 years and 9 months at the time of the first measurement. Variation in the quality of ultrasonographic images collected did not affect muscle depth measurements (P = 0.974). Further, there was good intra- and inter-observer repeatability for all observations (intraclass correlation range 0.97-0.99). There was a moderate positive association between EMH and body weight (r = 0.49, P <0.001) but no association with age (r = -0.05, P = 0.680). There were also positive associations in EMH among cats with different BCSs (P = 0.001) and SMAs (thoracic spine, P = 0.021; lumbar spine, P = 0.014), but breed (P = 0.429) and sex (P = 0.187) had no effect. Finally, there was no change in EMH measurements in the paired samples (P = 0.145) or correlation between percentage weight and EMH change over 12 months.

CONCLUSIONS AND RELEVANCE

The accuracy of EMH measurement using ultrasonographic imaging is good, irrespective of observer experience and provided that the ultrasonographer has some training. This suggests that ultrasonographic measurement of EMH could have a major practical impact as a non-invasive determination of muscle mass in pet cat populations. Further research is required to assess longitudinal changes in muscle mass over time in senior pet cats.