Defining terms commonly used in sarcopenia research: a glossary proposed by the Global Leadership in Sarcopenia (GLIS) Steering Committee

Sarcopenia

Sarcopenia is the accelerated loss of skeletal muscle mass and function commonly, but not exclusively, associated with advancing age. It is observed across many species including humans in whom it can lead to decline in physical function and mobility as well as to increased risk of adverse outcomes including falls, fractures and premature mortality. Although prevalence estimates vary because sarcopenia has been defined in different ways, even using a conservative approach, the prevalence is between 5% and 10% in the general population. A life course framework has been proposed for understanding not only the occurrence of sarcopenia in later life but also influences operating at earlier life stages with potentially important implications for preventive strategies. Harnessing progress in understanding the hallmarks of ageing has been key to understanding sarcopenia pathophysiology. Considerable convergence in approaches to diagnosis of sarcopenia has occurred over the last 10 years, with a growing emphasis on the central importance of muscle strength. Resistance exercise is currently the mainstay of treatment; however, it is not suitable for all. Hence, adjunctive and alternative treatments to improve quality of life are needed. An internationally agreed approach to definition and diagnosis will enable a step change in the field and is likely to be available in the near future through the Global Leadership Initiative in Sarcopenia.

Effects of exercise with or without β-hydroxy-β-methylbutyrate supplementation on muscle mass, muscle strength, and physical performance in patients with sarcopenia: a systematic review and meta-analysis

Objectives

This systematic review and meta-analysis aimed to assess the effects of exercise with/without β-hydroxy-β-methylbutyrate (HMB) supplementation on muscle mass, muscle strength, physical performance, and body composition in patients with sarcopenia.

Methods

A literature search for randomized controlled trials (RCTs) on the effects of exercise with or without HMB supplementation on muscle mass, muscle strength, physical performance, and body composition in patients with sarcopenia was conducted using PubMed, Web of Science, EBSCO, The Cochrane Library, EMBASE, Scopus, Science Direct, China Knowledge Resource Integrated Database (CNKI), and Wan Fang database. The search was limited to studies published up to April 2024 for each database. The outcome measures included muscle mass, muscle strength, physical performance, and body composition. The Cochrane Risk of Bias Assessment Tool was used to evaluate the quality of the included literature, and RevMan 5.4 software was employed to perform a meta-analysis of the outcome indicators.

Results

Five RCTs involving 257 elderly patients with sarcopenia were included in this study. Meta-analysis showed that in terms of physical performance, exercise with HMB supplementation significantly increased gait speed in sarcopenic patients compared to the exercise combined with the placebo group (SMD = 0.48, 95% CI: 0.15 to 0.82, p = 0.005), but exercise combined with HMB supplementation did not have significant effects on SMI (SMD = 0.06, 95% CI: -0.20 to 0.32, p = 0.66), grip strength (SMD = 0.23, 95% CI: -0.05 to 0.52, p = 0.11), five-time chair stand test (SMD = -0.83, 95% CI: -1.88 to 0.21, p = 0.12), fat-free mass (SMD = 0.04, 95% CI: -0.26 to 0.35, p = 0.78), BMI (SMD = -0.09, 95% CI: -0.43 to 0.25, p = 0.60), and fat mass (SMD = 0.01, 95% CI: -0.25 to 0.27, p = 0.94).

Conclusion

The current evidence indicates that exercise with HMB supplementation may enhance physical performance in patients with sarcopenia compared to exercise with the placebo group. However, the effects on muscle mass, muscle strength, and body composition are likely minimal. The above findings are limited by the number of included studies and require further validation through high-quality studies.

Systematic Review Registration

Prospero (CRD42024500135).

Association between sarcopenic obesity and knee osteoarthritis: A narrative review

Sarcopenia and obesity have been studied independently as risk factors for knee osteoarthritis. However, there is now research interest in investigating whether the co-existence of sarcopenia and obesity (sarcopenic obesity) within the same individual significantly increases the risk of knee osteoarthritis, compared to sarcopenia or obesity alone. This review synthesises current literature to explore the association between sarcopenic obesity and knee osteoarthritis, emphasising both the clinical evidence and existing gaps. We highlight the challenges and progress in defining sarcopenic obesity and discuss the impact that the lack of a consensus definition of sarcopenic obesity has on comparing outcomes of studies investigating the relationship between sarcopenic obesity and knee OA. We offer methodological insights to guide future studies investigating whether sarcopenic obesity increases the risk of knee osteoarthritis above and beyond the risk associated with each condition on its own. The implications for clinical practice are discussed, including the need to incorporate effective resistance exercise into weight loss programs for individuals with sarcopenic obesity. This is critical as a general weight loss program alone among individuals with sarcopenic obesity can include substantial loss of muscle mass, potentially predisposing patients to further functional decline.

Detecting sarcopenia in obesity: emerging new approaches

PURPOSE OF REVIEW

Sarcopenic obesity is a likely common, but certainly underestimated obesity phenotype, with an important negative clinical impact. Its definition and diagnosis have however remained elusive until recently.

RECENT FINDINGS

Substantial progress has been recently made in sarcopenic obesity diagnostic tools, with the first international consensus proposed by the European Society for Clinical Nutrition and Metabolism (ESPEN) and the European Association for the Study of Obesity (EASO). Very encouraging results emerge from initial implementation of the ESPEN-EASO algorithm. In addition, even more recent progress in global consensus on sarcopenia conceptual definition is likely to further enhance consistency in sarcopenic obesity identification. The latter Global Leadership Initiative on Sarcopenia (GLIS) initiative also adopted a new definition of muscle specific strength. Its inclusion in sarcopenia diagnostic constructs opens the possibility of its potential evaluation in sarcopenic obesity, also considering the emerging positive impact of obesity treatment and fat loss on muscle functional parameters.

SUMMARY

New consensus tools for sarcopenic obesity diagnosis are likely to improve awareness, understanding, identification and treatment of this under-recognized obesity phenotype.

Skeletal Muscle Texture Assessment Using Ultrasonography: Comparison with Magnetic Resonance Imaging in Chronic Kidney Disease

Skeletal muscle dysfunction is common in chronic kidney disease (CKD). Of interest is the concept of "muscle quality," of which measures include ultrasound-derived echo intensity (EI). Alternative parameters of muscle texture, for example, gray level of co-occurrence matrix (GCLM), are available and may circumvent limitations in EI. The validity of EI is limited in humans, particularly in chronic diseases. This study aimed to investigate the associations between ultrasound-derived parameters of muscle texture with MRI. Images of the thigh were acquired using a 3 Tesla MRI scanner. Quantification of muscle (contractile), fat (non-contractile), and miscellaneous (connective tissue, fascia) components were estimated. Anatomical rectus femoris cross-sectional area was measured using B-mode 2D ultrasonography. To assess muscle texture, first (i.e., EI)- and second (i.e., GLCM)-order statistical analyses were performed. Fourteen participants with CKD were included (age: 58.0 ± 11.9 years, 50% male, eGFR: 27.0 ± 7.4 ml/min/1.73m2, 55% Stage 4). Higher EI was associated with lower muscle % (quadriceps: β = -.568, p = .034; hamstrings: β = -.644, p = .010). Higher EI was associated with a higher fat % in the hamstrings (β = -.626, p = .017). A higher angular second moment from GLCM analysis was associated with greater muscle % (β = .570, p = .033) and lower fat % (β = -.534, p = .049). A higher inverse difference moment was associated with greater muscle % (β = .610, p = .021 and lower fat % (β = -.599, p = .024). This is the first study to investigate the associations between ultrasound-derived parameters of muscle texture with MRI. Our preliminary findings suggest ultrasound-derived texture analysis provides a novel indicator of reduced skeletal muscle % and thus increased intramuscular fat.

Can EWGSOP2 and SDOC Definitions of Sarcopenia Identify Functional Muscle Quality?

Objectives

To compare the European Working Group on Sarcopenia in Older People (EWGSOP2) and the Sarcopenia Definition and Outcomes Consortium (SDOC) in identifying muscle quality indexes (MQI) and lower limb muscle performance in older women aged ≥ 65.

Methods

Participants meeting EWGSOP2 and SDOC criteria were classified into the sarcopenia group (GS); others were placed in the non-sarcopenia group (GNS). Using an isokinetic dynamometer, we assessed peak torque (PT), maximal work (MW), and power (POW) of lower limbs. MQI was calculated as the ratio of muscle performance to appendicular lean mass, adjusted for body mass index (BMI) and lean tissue mass of the right lower limb (LTM).

Results

We included 96 older women. In both SDOC (n=37) and EWGSOP2 (n=48) sarcopenia groups, muscle performance and BMI-adjusted MQI were significantly lower. Sarcopenia (SDOC) was significantly associated with all lower limb muscle performance and MQI variables [adjusted model by age and race: MQIPOW/LTM OR = 0.67 (95% CI 0.52; 0.85); MQIPT/LTM OR = 0.76 (95% CI 0.64; 0.89)].

Conclusions

Older women diagnosed with sarcopenia by EWGSOP2 and SDOC criteria showed significant declines in muscle function and quality. The SDOC definition discriminated muscle contraction quality components in older individuals with and without sarcopenia.

Associations between gut microbiota and sarcopenia or its defining parameters in older adults: A systematic review

Altered gut microbiota (GM) potentially contribute to development or worsening of sarcopenia through a gut-muscle axis. This systematic review aims to compare GM between persons with sarcopenia or low sarcopenia-defining parameters (muscle mass, strength, and physical performance) to those with preserved muscle status, as well as to clarify possible associations between sarcopenia (-defining parameters) and relative abundance (RA) of GM-taxa or GM-(α- or β) diversity indices, in order to clarify whether there is robust evidence of the existence of a GM signature for sarcopenia. This systematic review was conducted according to the PRISMA-reporting guideline and pre-registered on PROSPERO (CRD42021259597). PubMed, Web of Science, Embase, ClinicalTrials.gov, and Cochrane library were searched until 20 July 2023. Included studies reported on GM and sarcopenia or its defining parameters. Observational studies were included with populations of mean age ≥50 years. Thirty-two studies totalling 10 781 persons (58.56% ♀) were included. Thirteen studies defined sarcopenia as a construct. Nineteen studies reported at least one sarcopenia-defining parameter (muscle mass, strength or physical performance). Studies found different GM-taxa at multiple levels to be significantly associated with sarcopenia (n = 4/6), muscle mass (n = 13/14), strength (n = 7/9), and physical performance (n = 3/3); however, directions of associations were heterogeneous and also conflicting for specific GM-taxa. Regarding β-diversity, studies found GM of persons with sarcopenia, low muscle mass, or low strength to cluster differently compared with persons with preserved muscle status. α-diversity was low in persons with sarcopenia or low muscle mass as compared with those with preserved muscle status, indicating low richness and diversity. In line with this, α-diversity was significantly and positively associated with muscle mass (n = 3/4) and muscle strength (n = 2/3). All reported results were significant (P < 0.05). Persons with sarcopenia and low muscle parameters have less rich and diverse GM and can be separated from persons with preserved muscle mass and function based on GM-composition. Sarcopenia and low muscle parameters are also associated with different GM-taxa at multiple levels, but results were heterogeneous and no causal conclusions could be made due to the cross-sectional design of the studies. This emphasizes the need for uniformly designed cross-sectional and longitudinal trials with appropriate GM confounder control in large samples of persons with sarcopenia and clearly defined core outcome sets in order to further explore changes in GM-taxa and to determine a sarcopenia-specific GM-signature.

Meta-analysis on the interrelationship between sarcopenia and mild cognitive impairment, Alzheimer's disease and other forms of dementia

Sarcopenia has been associated with adverse health outcomes, including cognitive dysfunction. However, its specific interrelationship with neurocognitive disorders such as mild cognitive impairment (MCI), Alzheimer's disease (AD) or other types of dementia has not been thoroughly explored. This meta-analysis aims to summarize the existing evidence on this interrelationship. This systematic review was pre-registered on PROSPERO (CRD42022366309) and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Databases, including PubMed, Embase, CINAHL, Scopus, Web of Science, PEDro, SPORTDiscus and the Cochrane Central Register of Controlled Trials, and the data registry ClinicalTrials.gov were searched from inception to 8 June 2023. Observational studies (cross-sectional and cohort) and interventional studies reporting on the association and prevalence of sarcopenia in MCI, AD or other types of dementia in adults ≥50 years were included. For the meta-analysis, pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated for the association of sarcopenia with the neurocognitive disorders using random-effects/fixed-effects models. Subgroup analyses were performed to identify potential sources of heterogeneity. A total of 77 studies consisting of 92 058 subjects were finally included in the qualitative analysis (71 cross-sectional, 4 cohort and 2 interventional studies). Studies were heterogeneous, using different diagnostic criteria to define both sarcopenia and cognitive status. The majority of studies (n = 38) included Asian community-dwelling older adults. Most studies investigated the association of sarcopenia with AD (33/77) and MCI (32/77). For studies focusing on other forms of dementia, two studies included Lewy body dementia and one study included Parkinson's dementia, whereas the remaining studies did not specify dementia aetiology (n = 21). Three cohort studies explored the association between sarcopenia and incident MCI, whereas only one cohort study explored the association between dementia and incident sarcopenia. Two interventional studies investigated whether an exercise programme could prevent the progression of sarcopenia in older adults with dementia or AD. The information for the meta-analysis was extracted from 26 studies. Sarcopenia was significantly associated with MCI (pooled OR = 1.58, 95% CI 1.42-1.76) (n = 14), AD (pooled OR = 2.97, 95% CI 2.15-4.08) (n = 3) and non-AD dementia (pooled OR = 1.68, 95% CI 1.09-2.58) (n = 9). The significance and magnitude of the associations differed in subgroup analyses by study design, population, definition of sarcopenia or used tool to measure cognitive status. This meta-analysis showed that sarcopenia is significantly associated with MCI, AD and other types of dementia. These findings suggest the importance of early screening and prevention of sarcopenia in older people with cognitive dysfunction, although further longitudinal research is needed to clarify the causal relationship.

Nutrition for the older adult - Current concepts. Report from an ESPEN symposium

BACKGROUND & AIMS

In view of the global demographic shift, a scientific symposium was organised by the European Society for Clinical Nutrition and Metabolism (ESPEN) to address nutrition-related challenges of the older population and provide an overview of the current state of knowledge.

METHODS

Eighteen nutrition-related issues of the ageing global society were presented by international experts during the symposium and summarised in this report.

RESULTS

Anorexia of ageing, dysphagia, malnutrition, frailty, sarcopenia, sarcopenic obesity, and the metabolic syndrome were highlighted as major nutrition-related geriatric syndromes. Great progress has been made in recent years through standardised definitions of some but not all syndromes. Regarding malnutrition, the GLIM approach has shown to be suitable also in older adults, justifying its continuous implementation. For anorexia of ageing, a consensus definition is still required. Intervention approaches should be integrated and person-centered with the aim of optimizing intrinsic capacity and maintaining functional capacity. Landmark studies like EFFORT and FINGER have impressively documented the potential of individualised and multifactorial interventions for functional and health benefits. Combining nutritional intervention with physical training seems particularly important whereas restrictive diets and drug treatment should generally be used with caution because of undesirable risks. Obesity management in older adults should take into account the risk of promoting sarcopenia.

CONCLUSIONS

In the future, even more individualised approaches like precision nutrition may enable better nutritional care. Meanwhile all stakeholders should focus on a better implementation of currently available strategies and work closely together to improve nutritional care for older adults.

Phase Angle but Not Psoas Muscle Predicts Nutritional Risk and Prognosis in Males with Hepatocellular Carcinoma

Despite those with hepatocellular carcinoma (HCC) being at increased risk of malnutrition, there is a notable absence of practical approaches for nutritional assessment in clinical practice. We investigated the usefulness of phase angle (PhA) and Total Psoas Area Index (TPAI) for indicating nutritional risk and HCC prognosis. Weight, height, body mass index (BMI), adductor pollicis muscle thickness (APMT), and handgrip strength (HGS) were assessed. The Nutritional Risk Index (NRI) was calculated. Body composition was assessed using bioimpedance spectroscopy and magnetic resonance imaging. The Child-Turcotte-Pugh (CTP) score and Barcelona-Clinic Liver Cancer (BCLC) classification determined the prognosis. Fifty-one males with HCC were enrolled (CTP C = 11.8%). PhA showed a moderate positive correlation with APMT (r = 0.450; p < 0.001) and HGS (r = 0.418; p = 0.002) and a weak positive correlation with TPAI (r = 0.332; p = 0.021). PhA had a strong positive correlation with NRI (r = 0.614; p < 0.001). Mean PhA values were significantly different according to disease severity (CTP C p = 0.001, and BCLC D p = 0.053). TPAI had no significant correlation with HGS, CTP, or BCLC. PhA was a superior approach for predicting nutritional risk and prognosis in HCC than TPAI. Lower PhA is associated with disease progression, lower muscle mass and function, greater severity of nutritional risk, and increased mortality in HCC.

Strength-to-muscle radiodensity: A potential new index for muscle quality

BACKGROUND & AIMS

Although it is widely recognized that muscle quality significantly influences adverse outcomes in patients with cancer, the precise definition of muscle quality remains elusive. The muscle quality index (MQI), also known as muscle-specific strength, is a relatively recent functional concept of muscle quality. It is obtained through the ratio of muscle strength to muscle mass, but its predictive value in patients with cancer remains unknown. In this study, we explored the prognostic significance of MQI in patients with cancer. Furthermore, we introduce and assess the prognostic potential of a novel muscle quality metric: the strength-to-muscle-radiodensity index (SMRi).

METHODS

A secondary analysis was conducted on a prospective cohort study. CT scans were opportunistically used to assess body composition parameters, including skeletal muscle mass (SM in cm2) and muscle radiodensity (SMD in HU) at the third lumbar vertebra (L3). Handgrip strength (HGS) was measured. MQICT was calculated using the ratio of HGS to SM (cm2). SMRi was calculated as the ratio of HGS to SMD (HU). For analysis purposes, low MQICT and SMRi were defined using two approaches: statistical cutoffs associated with survival, and median-based distribution data.

RESULTS

A total of 250 patients were included (52.8% females, 52% adults, 20-90 years). Gastrointestinal tumors and stage III-IV were the most frequent diagnosis and stages. SMRi and MQICT were strongly positively correlated (ρ = 0.71 P < 0.001). Individual components of MQICT and SMRi were also positively correlated. Patients with both low MQICT and SMRi had shorter survival (log-rank P = 0.023 and P = 0.003, respectively). When applying median distribution cutoffs, SMRi emerged as the most accurate predictor of mortality (HR adjusted 3.18, 95% CI 1.50 to 6.75, C-index: 0.71), when compared to MQICT (HR adjusted 1.49, 95% CI 0.77 to 2.87, C-index: 0.68).

CONCLUSION

This study introduces the concept and potential prognostic significance of the SMRi. The physiological and clinical implications of this new index warrant further investigation across a spectrum of diseases, including cancer.

Leukocyte telomere length is associated with MRI-thigh fat-free muscle volume: data from 16 356 UK Biobank adults

BACKGROUND

Telomere attrition may share common biological mechanisms with bone and muscle loss with aging. Here, we investigated the association between these hallmarks of aging using data from UK Biobank, a large observational study.

METHODS

Leukocyte telomere length (LTL as T/S ratio) was measured using a multiplex qPCR assay at baseline (2006-2010). Bone mineral density (whole body and regional; via dual-energy X-ray absorptiometry), trabecular bone score (via lumbar-spine dual-energy X-ray absorptiometry images), fat-free muscle volume (thighs; via magnetic resonance imaging), and muscle fat infiltration (thighs; via magnetic resonance imaging) were measured during the imaging visit (2014-2018). Regression models were used to model LTL against a muscle or bone outcome, unadjusted and adjusted for covariates.

RESULTS

A total of 16 356 adults (mean age: 62.8 ± 7.5 years, 50.5% women) were included. In the fully adjusted model, thigh fat-free muscle volume was associated with LTL in the overall sample (adjusted standardized β (aβ) = 0.017, 95% CI 0.009 to 0.026, P < 0.001, per SD increase in LTL), with stronger associations in men (aβ = 0.022, 95% CI 0.010 to 0.034, P < 0.001) than in women (aβ = 0.013, 95% CI 0.000 to 0.025, P = 0.041) (sex-LTL P = 0.028). The adjusted odds ratio (aOR) for low thigh fat-free muscle volume (body mass index-adjusted, sex-specific bottom 20%) was 0.93 per SD increase in LTL (95% CI 0.89 to 0.96, P < 0.001) in the overall sample, with stronger associations in men (aOR = 0.92, 95% CI 0.87 to 0.99, P = 0.008) than women (aOR = 0.93, 95% CI 0.88 to 0.98, P = 0.009), although the sex difference was not statistically significant in this model (sex-LTL P = 0.37). LTL was not associated with bone mineral density, trabecular bone score, or muscle fat infiltration in the overall or subgroup analyses (P > 0.05).

CONCLUSIONS

LTL was consistently associated with thigh fat-free muscle volume in men and women. Future research should investigate moderating effects of lifestyle factors (e.g., physical activity, nutrition, or chronic diseases) in the association between LTL and muscle volume.

A protocol for remote collection of skeletal muscle mass via D3-creatine dilution in community-dwelling postmenopausal women from the Women's Health Initiative

BACKGROUND

There is emerging evidence that cancer and its treatments may accelerate the normal aging process, increasing the magnitude and rate of decline in functional capacity. This accelerated aging process is hypothesized to hasten the occurrence of common adverse age-related outcomes in cancer survivors, including loss of muscle mass and decrease in physical function. However, there is no data describing age-related loss of muscle mass and its relation to physical function in the long-term in cancer survivors.

METHODS

This study protocol describes the use of a novel method of muscle mass measurement, D3-creatine dilution method (D3Cr), in a large sample (n~6000) of community dwelling postmenopausal women from the Women's Health Initiative (WHI). D3Cr will be used to obtain a direct measure of muscle mass remotely. Participants will be drawn from two sub-cohorts embedded within the WHI that have recently completed an in-home visit. Cancer survivors will be drawn from the Life and Longevity After Cancer (LILAC) cohort, and cancer-free controls will be drawn from the WHI Long Life Study 2. The overall objective of this study is to examine the antecedents and consequences of low muscle mass in cancer survivors. The study aims are to: 1) create age-standardized muscle mass percentile curves and z-scores to characterize the distribution of D3- muscle mass in cancer survivors and non-cancer controls, 2) compare muscle mass, physical function, and functional decline in cancer survivors and non- cancer controls, and 3) use machine learning approaches to generate multivariate risk-prediction algorithms to detect low muscle mass.

DISCUSSION

The D3Cr method will transform our ability to measure muscle mass in large-scale epidemiologic research. This study is an opportunity to advance our understanding of a key source of morbidity among older and long-term female cancer survivors. This project will fill knowledge gaps, including the antecedents and consequences of low muscle mass, and use innovative methods to overcome common sources of bias in cancer research. The results of this study will be used to develop interventions to mitigate the harmful effects of low muscle mass in older adults and promote healthy survivorship in cancer survivors in the old (>65) and oldest-old (>85) age groups.

Muscle parameters in fragility fracture risk prediction in older adults: A scoping review

Half of osteoporotic fractures occur in patients with normal/osteopenic bone density or at intermediate or low estimated risk. Muscle measures have been shown to contribute to fracture risk independently of bone mineral density. The objectives were to review the measurements of muscle health (muscle mass/quantity/quality, strength and function) and their association with incident fragility fractures and to summarize their use in clinical practice. This scoping review follows the PRISMA-ScR guidelines for reporting. Our search strategy covered the three overreaching concepts of 'fragility fractures', 'muscle health assessment' and 'risk'. We retrieved 14 745 references from Medline Ovid SP, EMBASE, Web of Science Core Collection and Google Scholar. We included original and prospective studies on community-dwelling adults aged over 50 years that analysed an association between at least one muscle parameter and incident fragility fractures. We systematically extracted 17 items from each study, including methodology, general characteristics and results. Data were summarized in tables and graphically presented in adjusted forest plots. Sixty-seven articles fulfilled the inclusion criteria. In total, we studied 60 muscle parameters or indexes and 322 fracture risk ratios over 2.8 million person-years (MPY). The median (interquartile range) sample size was 1642 (921-5756), age 69.2 (63.5-73.6) years, follow-up 10.0 (4.4-12.0) years and number of incident fragility fractures 166 (88-277). A lower muscle mass was positively/not/negatively associated with incident fragility fracture in 28 (2.0), 64 (2.5) and 10 (0.2 MPY) analyses. A lower muscle strength was positively/not/negatively associated with fractures in 53 (1.3), 57 (1.7 MPY) and 0 analyses. A lower muscle function was positively/not/negatively associated in 63 (1.9), 45 (1.0 MPY) and 0 analyses. An in-depth analysis shows how each single muscle parameter was associated with each fragility fractures subtype. This review summarizes markers of muscle health and their association with fragility fractures. Measures of muscle strength and function appeared to perform better for fracture risk prediction. Of these, hand grip strength and gait speed are likely to be the most practical measures for inclusion in clinical practice, as in the evaluation of sarcopenia or in further fracture risk assessment scores. Measures of muscle mass did not appear to predict fragility fractures and might benefit from further research, on D3-creatine dilution test, lean mass indexes and artificial intelligence methods.

The Conceptual Definition of Sarcopenia: Delphi Consensus from the Global Leadership Initiative in Sarcopenia (GLIS)

IMPORTANCE

Sarcopenia, the age-related loss of muscle mass and strength/function, is an important clinical condition. However, no international consensus on the definition exists.

OBJECTIVE

The Global Leadership Initiative in Sarcopenia (GLIS) aimed to address this by establishing the global conceptual definition of sarcopenia.

DESIGN

The GLIS steering committee was formed in 2019-21 with representatives from all relevant scientific societies worldwide. During this time, the steering committee developed a set of statements on the topic and invited members from these societies to participate in a two-phase International Delphi Study. Between 2022 and 2023, participants ranked their agreement with a set of statements using an online survey tool (SurveyMonkey). Statements were categorised based on predefined thresholds: strong agreement (>80%), moderate agreement (70-80%) and low agreement (<70%). Statements with strong agreement were accepted, statements with low agreement were rejected and those with moderate agreement were reintroduced until consensus was reached.

RESULTS

107 participants (mean age: 54 ± 12 years [1 missing age], 64% men) from 29 countries across 7 continents/regions completed the Delphi survey. Twenty statements were found to have a strong agreement. These included; 6 statements on 'general aspects of sarcopenia' (strongest agreement: the prevalence of sarcopenia increases with age (98.3%)), 3 statements on 'components of sarcopenia' (muscle mass (89.4%), muscle strength (93.1%) and muscle-specific strength (80.8%) should all be a part of the conceptual definition of sarcopenia)) and 11 statements on 'outcomes of sarcopenia' (strongest agreement: sarcopenia increases the risk of impaired physical performance (97.9%)). A key finding of the Delphi survey was that muscle mass, muscle strength and muscle-specific strength were all accepted as 'components of sarcopenia', whereas impaired physical performance was accepted as an 'outcome' rather than a 'component' of sarcopenia.

CONCLUSION AND RELEVANCE

The GLIS has created the first global conceptual definition of sarcopenia, which will now serve to develop an operational definition for clinical and research settings.

Obstacles to the Early Diagnosis and Management of Sarcopenia: Current Perspectives

Research in sarcopenia has grown exponentially over the last 15 years in geriatrics and gerontology, as well as other specialties, including oncology and hepatology. There is now strong evidence for the role of resistance exercise to prevent declines in muscle strength and function, especially when combined with nutritional optimization with protein supplementation. However, there remains a disparity between research evidence and clinical practice. There are multiple factors for this, which relate to the current diagnostic criteria for sarcopenia, practical and logistical aspects of diagnosis of sarcopenia, clinician knowledge of both diagnosis and management, and the availability of pathways for interventions. Sarcopenia is currently defined based on the identification of muscle strength, in combination with muscle size or quality, below cut-off thresholds at a single timepoint. This defines sarcopenia as a binary process of either present or not present, thus early diagnosis can be challenging. In this article, we summarize current obstacles to early diagnosis and management of sarcopenia in clinical practice, and make recommendations to how these might be overcome. This includes our recommendation of incorporation of handgrip strength measurement into standard care, to enable dynamic assessment and identification of early declines in handgrip strength, so that interventions can be implemented to prevent disability.

The Current Landscape of Pharmacotherapies for Sarcopenia

Sarcopenia is a skeletal muscle disorder characterized by progressive and generalized decline in muscle mass and function. Although it is mostly known as an age-related disorder, it can also occur secondary to systemic diseases such as malignancy or organ failure. It has demonstrated a significant relationship with adverse outcomes, e.g., falls, disabilities, and even mortality. Several breakthroughs have been made to find a pharmaceutical therapy for sarcopenia over the years, and some have come up with promising findings. Yet still no drug has been approved for its treatment. The key factor that makes finding an effective pharmacotherapy so challenging is the general paradigm of standalone/single diseases, traditionally adopted in medicine. Today, it is well known that sarcopenia is a complex disorder caused by multiple factors, e.g., imbalance in protein turnover, satellite cell and mitochondrial dysfunction, hormonal changes, low-grade inflammation, senescence, anorexia of aging, and behavioral factors such as low physical activity. Therefore, pharmaceuticals, either alone or combined, that exhibit multiple actions on these factors simultaneously will likely be the drug of choice to manage sarcopenia. Among various drug options explored throughout the years, testosterone still has the most cumulated evidence regarding its effects on muscle health and its safety. A mas receptor agonist, BIO101, stands out as a recent promising pharmaceutical. In addition to the conventional strategies (i.e., nutritional support and physical exercise), therapeutics with multiple targets of action or combination of multiple therapeutics with different targets/modes of action appear to promise greater benefit for the prevention and treatment of sarcopenia.

Sarcopenia: no consensus, no diagnostic criteria, and no approved indication-How did we get here?

In addition to the role of skeletal muscle in movement and locomotion, muscle plays a critical role in a broad array of metabolic processes that can contribute to improved health or risk of disease. The age-associated loss of muscle has been termed sarcopenia. The muscle is the primary site of insulin-stimulated glucose disposal and the largest component of basal metabolic rate, directly and indirectly affects bone density, produces myokines with pleiotropic effect on muscle and other tissues including the brain, and stores essential amino acids essential for the maintenance of protein synthesis during periods of reduced food intake and stress. As such, not surprisingly deterioration of skeletal muscle health, typically operationalized as decline of muscle mass and muscle strength is both a powerful risk factor and main consequence of chronic diseases, disability, and loss of independence, and it is one of the strongest risk factors for mortality. However, skeletal muscle remains one of the most plastic of all tissues, with rapid changes in rates of protein synthesis and degradation in response to physical activity and inactivity, inflammation, and nutritional and hormonal status. This has made the development of pharmacological therapies to increase muscle mass (or prevent loss), an important goal for decades. However, while remarkable advances in the understanding of molecular and cellular regulation of muscle protein metabolism have occurred recently, there are no approved drugs for the treatment of sarcopenia, the loss of skeletal muscle affecting millions of older people. The goal of this paper is to describe the possible reasons for the lack of new and effective pharmacotherapies to treat one of the most important risk factors for age-associated disease and loss of independence.

Association between sarcopenia and multimorbidity among middle-aged and older adults in China: Findings from the China Health and Retirement Longitudinal Study

BACKGROUND

Little is known about the association between sarcopenia and multimorbidity among middle-aged and older adults. This study investigated whether sarcopenia is associated with multimorbidity in middle-aged and older Chinese individuals.

MATERIALS AND METHODS

A total of 12,760 participants from China Health and Retirement Longitudinal Study (CHARLS) 2015, with data on 14 specified chronic diseases and sarcopenia status were included in the cross-sectional analysis. A total of 7345 participants without multimorbidity from the CHARLS 2015 were included and followed up in 2018 in the longitudinal analysis. Logistic regression models were used in a cross-sectional investigation to assess the association between sarcopenia status and multimorbidity. In a longitudinal analysis, the relationships between sarcopenia status and multimorbidity were investigated using Cox proportional hazards models.

RESULTS

Multimorbidity was prevalent in the no sarcopenia, possible sarcopenia, and sarcopenia groups at 38.8 % (3765/9713), 56.6 % (1199/2118), and 48.5 % (451/929), respectively. Multivariable regression revealed that both possible sarcopenia (β = 0.088, P<0.001) and sarcopenia (β = 0.028, P = 0.009), contributed to the number of chronic diseases. Logistic regression revealed that possible sarcopenia (OR: 1.56, 95 % CI: 1.39-1.76) was associated with multimorbidity. In the longitudinal analysis, participants in the possible sarcopenia group (HR: 1.19, 95 % CI:1.03-1.38) were more prone to experience new onset multimorbidity than did participants in the no sarcopenia group.

CONCLUSIONS

Possible sarcopenia is associated with the development of multimorbidity in middle-aged and older Chinese populations. Health screening of populations with possible sarcopenia can facilitate early detection of multimorbidity.

A Critical Review of Current Worldwide Definitions of Sarcopenia

With the increasing number of elderly individuals worldwide, the prevalence of age-related loss of muscle mass, referred to as sarcopenia, is expected to increase. Sarcopenia is a relatively new recognized syndrome, which is thought to affect 13% individuals worldwide, and the significant efforts made by different groups have advanced our understanding of the diagnosis, treatment, and natural history of this condition. However, the challenge is now to standardize its measurement and diagnosis to facilitate research in this area and a greater understanding of this condition and its management between clinicians and researchers. The Global Leadership Initiative on Sarcopenia (GLIS) is at the forefront of an international effort to produce standardized definition of sarcopenia. Setting a definition for sarcopenia entails several considerations and trade-offs. In this critical review, we have addressed key challenges driving the process of standardizing the definition, while delving into future avenues in sarcopenia research. Establishing a clear consensus on the working definition of sarcopenia is essential not only for advancing research in this field but also for assessing the prognostic implications of diagnosing sarcopenia and determining the most suitable treatment for affected patients.

Predicting Slow Walking Speed From a Pooled Cohort Analysis: Sarcopenia Definitions, Agreement, and Prevalence in Australia and New Zealand

BACKGROUND

Recent operational definitions of sarcopenia have not been replicated and compared in Australia and New Zealand (ANZ) populations. We aimed to identify sarcopenia measures that discriminate ANZ adults with slow walking speed (<0.8 m/s) and determine the agreement between the Sarcopenia Definitions and Outcomes Consortium (SDOC) and revised European Working Group for Sarcopenia in Older People (EWGSOP2) operational definitions of sarcopenia.

METHODS

Eight studies comprising 8 100 ANZ community-dwelling adults (mean age ± standard deviation, 62.0 ± 14.4 years) with walking speed, grip strength (GR), and lean mass data were combined. Replicating the SDOC methodology, 15 candidate variables were included in sex-stratified classification and regression tree models and receiver operating characteristic curves on a pooled cohort with complete data to identify variables and cut points discriminating slow walking speed (<0.8 m/s). Agreement and prevalence estimates were compared using Cohen's Kappa (CK).

RESULTS

Receiver operating characteristic curves identified GR as the strongest variable for discriminating slow from normal walking speed in women (GR <20.50 kg, area under curve [AUC] = 0.68) and men (GR <31.05 kg, AUC = 0.64). Near-perfect agreement was found between the derived ANZ cut points and SDOC cut points (CK 0.8-1.0). Sarcopenia prevalence ranged from 1.5% (EWGSOP2) to 37.2% (SDOC) in women and 1.0% (EWGSOP2) to 9.1% (SDOC) in men, with no agreement (CK <0.2) between EWGSOP2 and SDOC.

CONCLUSIONS

Grip strength is the primary discriminating characteristic for slow walking speed in ANZ women and men, consistent with findings from the SDOC. Sarcopenia Definitions and Outcomes Consortium and EWGSOP2 definitions showed no agreement suggesting these proposed definitions measure different characteristics and identify people with sarcopenia differently.

Muscle quality an evolving concept

Muscle quality concept can be analyzed from a morphological and functional perspectives that include relation between these properties. Morphological muscle quality considers muscle composition, architectural and structural properties. Functional muscle quality has been defined as a ratio between muscle strength or power per unit of muscle mass or area. Biological and adaptative changes to ageing must be considered when interpretation of muscle quality assessment is done in a clinical or research context. One of the conditions that requires an adequate homologation in terminology is sarcopenia, to establish definition and cut-off points.

The prevalence of sarcopenia in Parkinson's disease and related disorders- a systematic review

BACKGROUND

The prevalence of sarcopenia (reduced skeletal muscle strength and mass), Parkinson's disease (PD) and Parkinson's related disorders (PRD) all increase with age. They also share risk factors and pathogenetic features. An increased prevalence of sarcopenia in PD and PRD than the general population was thus postulated.

METHODS

Four databases were searched using predefined literature search strategies. Studies conducted in participants with PD or PRD reporting the prevalence of sarcopenia and those providing data to compute the prevalence were included. Pre-sarcopenia, probable/possible sarcopenia and confirmed sarcopenia were defined according to the main sarcopenia working groups. Risk of bias was assessed using the AXIS tool.

RESULTS

1978 studies were identified; 97 assessed in full; 14 met inclusion criteria. The median study quality score was 15/20. The range of probable sarcopenia was 23.9 to 66.7%, and it did not change after excluding PRD participants. The prevalence of confirmed sarcopenia in participants with any parkinsonian disorder ranged from 2 to 31.4%. Including just PD participants, the range was 10.9 to 31.4%. In studies with controls, sarcopenia was more prevalent in PD and PRD. There was a positive non-significant trend between severity of motor symptoms and prevalence of sarcopenia or components of sarcopenia. High heterogeneity precluded meta-analysis, therefore there was insufficient evidence to conclude whether sarcopenia is more prevalent in PD or PRD.

CONCLUSIONS

Probable and confirmed sarcopenia are common in PD and PRD and they may be associated with disease severity. This co-occurrence supports the value of screening for sarcopenia in parkinsonian populations.

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.

Mortality, falls and slow walking speed are predicted by different muscle strength and physical performance measures in women and men

BACKGROUND

Different measures of muscle strength, physical performance and body size/composition are used in various sarcopenia definitions. This study investigated which baseline measures best predict incident mortality and falls, and prevalent slow walking speed in older women and men.

MATERIALS AND METHODS

Data for 899 women (mean age±standard deviation, 68.7 ± 4.3 years) and 497 men (69.4 ± 3.9 years) from the Dubbo Osteoporosis Epidemiology Study 2, comprising sixty variables for muscle strength (quadriceps strength), physical performance (walking speed, timed up and go (TUG) test, sit to stand (STS) test), body size (weight, height, body mass index) and body composition (lean mass, body fat) were included. Sex-stratified Classification and Regression Tree (CART) analyses calculated baseline variable accuracy for predicting incident mortality and falls, and prevalent slow walking speed (<0.8 m/s).

RESULTS

Over 14.5 years, 103/899 (11.5%) women and 96/497 (19.3%) men died, 345/899 (38.4%) women and 172/497 (34.6%) men had ≥1 fall, and 304/860 (35.3%) women and 172/461 (31.7%) had baseline slow walking speed (<0.8 m/s). CART models identified age and walking speed adjusted for height as the most important predictors for mortality in women, and quadriceps strength (with adjustments) as the most important predictor for mortality in men. In both sexes, STS (with adjustments) was the most important predictor for incident falls, and TUG test was the most important predictor for prevalent slow walking speed. Body composition measures were not important predictors for any outcome.

CONCLUSIONS

Muscle strength and physical performance variables and cut points predict falls and mortality differently in women and men, suggesting targeted sex-specific application of selected measures may improve outcome prediction in older adults.

The role of nutrition in the prevention of sarcopenia

Sarcopenia is a common skeletal muscle disorder characterized by a loss of muscle mass and impaired muscle function that is associated with poor health outcomes. Although nutrition is considered an important factor in the etiology of sarcopenia, the preventive potential of diet, specifically the extent to which differences in habitual patterns of diet and/or nutrient intakes impact risk of its development, is poorly understood. This narrative review considered research evidence on dietary patterns and nutrient intakes in mid- (<60 y) and young-older (60-70 y) adulthood to evaluate how they relate to age-related changes in muscle mass and function. A key finding was that current evidence on adult diet and sarcopenia risk in older age is limited and fragmented, with different outcomes reported across studies (for example, lean mass, strength) and few reporting links to incident diagnosed sarcopenia. As these outcomes are not interchangeable, it challenges collation of the evidence, leaving many gaps in understanding. There is also limited information about adult (<70 y) diet and few longitudinal studies with repeated dietary assessments to enable definition of cumulative exposures across adulthood. However, despite these limitations, findings from studies of dietary patterns already provide reasonably consistent messages about the benefits of diets of higher quality in earlier adulthood for later physical performance, although whole-diet intervention trials are urgently needed to understand their potential. In comparison, there is little evidence of benefits of higher intakes of individual nutrients in earlier adulthood for later muscle mass and function. Although these gaps need to be addressed in future research, there may already be sufficient data to promote messages about diet quality more widely - that healthier diets of higher quality across adulthood, with known benefits for a range of health outcomes, are also linked to the effective preservation of muscle mass and function.

New perspectives on frailty in light of the Global Leadership Initiative on Malnutrition, the Global Leadership Initiative on Sarcopenia, and the WHO's concept of intrinsic capacity: A narrative review

This review gathered the evidence on the epidemiology of frailty, as well as on screening and diagnostic tools, and new perspectives, in light of the latest global frameworks in malnutrition, sarcopenia, and the World Health Organization's concept of intrinsic capacity. Frailty is a worldwide health challenge and highly prevalent in older adults and the population with chronic diseases independent of age. Regardless of the particular concept of frailty, many screening and diagnostic tools are able to identify frailty in older people, but none of them has shown superiority in every population and healthcare setting. Physical, cognitive, and social components are part of the larger context of frailty. The latest evidence-based initiatives on frailty recommend the use of validated tools to identify frailty's different components, tailored to the needs of specific populations and healthcare systems. Unintentional weight loss is a shared criterion between physical frailty and malnutrition according to the Global Leadership Initiative on Malnutrition criteria. A new definition of sarcopenia by the Global Leadership Initiative on Sarcopenia is awaited, but at present physical frailty shares with sarcopenia the criteria of low muscle function and physical performance (severity grading) according to the revised consensus of the European Working Group on Sarcopenia in Older People (EWGSOP2). The EWGSOP2 includes both muscle mass and function, with most scientific groups agreeing that function is a key hallmark of sarcopenia. The concept of intrinsic capacity features the reserves and positive aspects of aging, and responds to ageism by addressing the deficit model approach. Intrinsic capacity is an emerging, person-centered and public health indicator, aimed at preserving health at mid-life and beyond, to move towards a better aging process in the Decade of Healthy Aging 2020-2030.

Measures of attributes of locomotor capacity in older people: a systematic literature review following the COSMIN methodology

BACKGROUND

Locomotor capacity (LC) is an important domain of intrinsic capacity and key determinant of functional ability and well-being in older age. The United Nations Decade of Healthy Ageing (2021-2030) calls for strengthening data and research on healthy ageing, including the measurement of older persons' LC. To advance the measurement and monitoring of LC, there is pressing need to identify valid and reliable measures.

OBJECTIVE

To identify all the available tools that were validated for measurement of LC or of its specific attributes in older people and to assess the methodological quality of the studies and measurement properties of the tools.

DESIGN

Systematic review.

SETTING

Anywhere (Community-dwelling; long-term care facility; etc.).

SUBJECTS

Older people.

METHODS

We used highly sensitive search strategies to search the following databases: Medline, Embase, Scopus, CINAHL and PsycINFO. The study was conducted following the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) methodology for systematic review of outcome measurement instruments.

RESULTS

A total of 125 studies were included, which assessed tools for balance (n = 84), muscle power (n = 12), muscle strength (n = 32, including four studies about tools for balance and muscle power) and endurance (n = 1). No studies on tools for muscle function, joint function, or locomotor capacity overall, were retrieved. We identified 69 clinician-report or objective assessment tools for balance, 30 for muscle strength, 12 for muscle power and 1 endurance assessment tool. The GRADE assessment of quality of evidence showed that only a few tools have high quality evidence for both sufficient validity and reliability: The Balance Evaluation Systems Test (BESTest), the Mini-Balance Evaluation Systems Test (Mini-BESTest), the Berg Balance Scale (BBS) and the Timed Up and Go (TUG) test.

CONCLUSIONS

A few tools with high quality evidence for sufficient validity and reliability are currently available for balance assessment in older people that may be recommended for use in clinical and research settings. Further validation studies are required for muscle strength, muscle power and endurance assessment tools.

Chronic inflammation does not mediate the effect of adiposity on grip strength: results from a multivariable Mendelian randomization study

The relationship between adiposity and grip strength (GS) is complex. We investigated whether one pathway through which adiposity affects GS was via chronic inflammation. 367,583 UK Biobank participants had body mass index (BMI), waist-hip-ratio (WHR), C-reactive protein (CRP) and GS data. Univariable Mendelian randomization (MR) and multivariable Mendelian randomization (MVMR) analyses (using inverse variance weighted (IVW) weighted median estimates (WME) and MR-Egger models) estimated total, direct and indirect effects of adiposity traits on GS using genetic instruments for BMI and WHR (exposures) and CRP (mediator). Observational findings suggested higher BMI was associated with stronger grip, e.g., in males, per standard deviation (SD) higher BMI, GS was higher by 0.48 kg (95% confidence interval(CI):0.44,0.51), independent of CRP. For males MR estimates were directionally consistent; for females, estimates were consistent with the null. Observational findings for WHR suggested that higher WHR was associated with weaker grip. In multivariable MR-IVW analyses, effects in males were consistent with the null. In females, there were consistent effects such that higher WHR was associated with stronger grip, e.g., 1-SD higher WHR was associated with 1.25 kg (MVMR-Egger; 95% CI:0.72,1.78) stronger grip, independent of CRP. Across sexes and adiposity indicators, CRP's mediating role was minor. Greater adiposity may increase GS in early old age, but effects vary by sex and adiposity location. There was no evidence that inflammation mediated these effects.

Old muscle, new tricks: a clinician perspective on sarcopenia and where to next

PURPOSE OF REVIEW

This review offers a contemporary clinical approach to the recognition, prevention and management of sarcopenia, and discusses recent clinically relevant advances in the aetiopathogenesis of muscle ageing that may lead to future therapeutic targets.

RECENT FINDINGS

The key recent directions for sarcopenia are in the diagnosis, understanding molecular mechanisms and management. Regarding the recognition of the condition, it has become increasingly clear that different definitions hamper progress in understanding. Therefore, the Global Leadership in Sarcopenia has been established in 2022 to develop a universally accepted definition. Moreover, substantial work is occurring to understand the various roles and contribution of inflammation, oxidative stress, mitochondrial dysfunction and metabolic dysregulation on skeletal muscle function and ageing. Finally, the role of resistance-based exercise regimes has been continually emphasised. However, the role of protein supplementation and hormone replacement therapy (HRT) are still under debate, and current clinical trials are underway.

SUMMARY

With the global ageing of our population, there is increasing emphasis on maintaining good health. Maintenance of skeletal muscle strength and function are key to preventing frailty, morbidity and death.

Intrinsic capacity and risk of death: Focus on the impact of using different diagnostic criteria for the nutritional domain

OBJECTIVE

We aimed to estimate the ability of intrinsic capacity (IC) to predict death in community-dwelling older people using different diagnostic criteria to define the nutritional domain.

METHODS

Participants from the Belgian SarcoPhAge cohort were followed from 2013 to the present. Four IC domains were assessed at baseline (data on the sensorial domain were not collected), and considered unsatisfactory below some specific thresholds. The nutritional domain was considered unsatisfactory if baseline malnutrition was present, defined by: 1) MNA-SF ≤11 points; 2) seven versions of the GLIM criteria, varying by the technique used to identify a reduced muscle mass; or 3) the combination of MNA-SF ≤11 points + GLIM criteria. The association between baseline unsatisfactory IC and 9-year mortality was calculated using the odds ratio (OR) adjusted for cofounders.

RESULTS

Among the 534 participants (73.5 ± 6.2 years old; 60.3 % women at baseline), 157 (29.4 %) were dead after 9.3 ± 0.3 years of follow-up. Patients with baseline unsatisfactory IC in the locomotor domain (adjusted OR = 2.31 [95%CI 1.38-3.86]) or psychological domain (adjusted OR = 1.78 [1.12-2.83]) were at higher mortality risk. Regarding malnutrition, unsatisfactory IC in the nutrition domain was strongly associated with a higher mortality risk, whatever the criteria used to identify a reduced muscle mass. The highest association with mortality was found in participants with a baseline unsatisfactory nutritional domain defined by the combination of MNA-SF + GLIM criteria (adjusted OR = 3.27 [95%CI 1.72-6.23]).

CONCLUSIONS

Presenting any unsatisfactory IC at baseline was associated with a higher 9-year mortality risk in community-dwelling older people. The sequential incorporation of MNA-SF and GLIM criteria as the IC nutritional domain would be helpful to guide public health actions towards healthy ageing.

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.

Association between GLIM-defined malnutrition and hospitalizations in kidney transplant candidates: A post hoc analysis of a cohort study

BACKGROUND

Malnutrition is frequent in patients with chronic kidney disease (CKD) and has a negative impact on morbidity, mortality, and quality of life. The objective of this study was to assess the value of the Global Leadership Initiative for Malnutrition (GLIM) criteria to predict hospitalizations and mortality in candidates to kidney transplant during their first year on the waiting list.

METHODS

This was a post hoc analysis of 368 patients with advanced CKD. The main study variables were malnutrition, according to the GLIM criteria; number of hospital admissions during the first year on the waiting list; and mortality at the end of follow-up. Kaplan-Meier survival curves and binary logistic regression were performed, adjusting for age, frailty status, handgrip strength, and Charlson Index as potential confounders.

RESULTS

The prevalence of malnutrition was 32.6%. Malnutrition was associated with increased risk of hospitalizations during the first year on the waiting list (odds ratio [OR] = 3.33 [95% CI = 1.34-8.26]), which persisted after adjustment for age and frailty status (adjusted OR = 3.61 [95% CI = 1.38-10.7]), age and handgrip strength (adjusted OR = 3.39 [95% CI = 1.3-8.85]), and age and Charlson Index (adjusted OR = 3.25 [95% CI = 1.29-8.13]).

CONCLUSION

Malnutrition according to the GLIM criteria was highly prevalent in patients with CKD and was associated with a threefold increased risk of hospitalizations during the first year on the waiting list; these associations remained significant after adjusting for age, frailty status, handgrip strength, and comorbidities.

Defining and diagnosing sarcopenia: Is the glass now half full?

Low muscle mass and function exert a substantial negative impact on quality of life, health and ultimately survival, but their definition, identification and combination to define sarcopenia have suffered from lack of universal consensus. Methodological issues have also contributed to incomplete agreement, as different approaches, techniques and potential surrogate measures inevitably lead to partly different conclusions. As a consequence: 1) awareness of sarcopenia and implementation of diagnostic procedures in clinical practice have been limited; 2) patient identification and evaluation of therapeutic strategies is largely incomplete. Significant progress has however recently occurred after major diagnostic algorithms have been developed, with common features and promising perspectives for growing consensus. At the same time, the need for further refinement of the sarcopenia concept has emerged, to address its increasingly recognized clinical heterogeneity. This includes potential differential underlying mechanisms and clinical features for age- and disease-driven sarcopenia, and the emerging challenge of sarcopenia in persons with obesity. Here, we will review existing algorithms to diagnose sarcopenia, and major open methodological issues to assess skeletal muscle mass and function under different clinical conditions, in order to highlight similarities and differences. Potential for consensus on sarcopenia diagnosis as well as emerging new challenges will be discussed.

[Sarcopenia in chronic liver diseases]

BACKGROUND

Sarcopenia is a progressive and generalized disorder of the skeletal musculature that involves the loss of skeletal muscle mass and function. Patients with chronic liver disease frequently have sarcopenia in advanced stages of the disease; however, there is an increased prevalence of sarcopenia not only in liver cirrhosis but also in earlier stages of disease, e.g., in non-alcoholic fatty liver disease (NAFLD).

RESULTS

Sarcopenia is an independent prognostic risk factor for morbidity and mortality in patients with liver cirrhosis. The pathogenesis of sarcopenia is multifactorial and in chronic liver diseases a lower oral energy intake, altered ammonia metabolism, hormonal imbalances and a chronic low-grade inflammatory state are important. When the screening test is positive, determination of the muscle strength, e.g., measurement of hand grip strength, is recommended for the diagnostic approach. Lower muscle strength leads to further measurement of muscle mass to confirm the diagnosis of sarcopenia. In patients with chronic liver disease abdominal imaging by computed tomography or magnetic resonance imaging is particularly suitable for this. The severity of sarcopenia is classified by the physical performance. Therapeutic strategies for the treatment of sarcopenia include nutritional therapy as well as exercise therapy.

CONCLUSION

Patients with chronic liver diseases frequently have sarcopenia. This is an independent prognostic risk factor. Therefore, sarcopenia should be considered in the diagnostics and therapeutic approaches.

Temporal, Kinematic and Kinetic Variables Derived from a Wearable 3D Inertial Sensor to Estimate Muscle Power during the 5 Sit to Stand Test in Older Individuals: A Validation Study

The 5-Sit-to-stand test (5STS) is widely used to estimate lower limb muscle power (MP). An Inertial Measurement Unit (IMU) could be used to obtain objective, accurate and automatic measures of lower limb MP. In 62 older adults (30 F, 66 ± 6 years) we compared (paired t-test, Pearson's correlation coefficient, and Bland-Altman analysis) IMU-based estimates of total trial time (totT), mean concentric time (McT), velocity (McV), force (McF), and MP against laboratory equipment (Lab). While significantly different, Lab vs. IMU measures of totT (8.97 ± 2.44 vs. 8.86 ± 2.45 s, p = 0.003), McV (0.35 ± 0.09 vs. 0.27 ± 0.10 m∙s^-1, p < 0.001), McF (673.13 ± 146.43 vs. 653.41 ± 144.58 N, p < 0.001) and MP (233.00 ± 70.83 vs. 174.84 ± 71.16 W, p < 0.001) had a very large to extremely large correlation (r = 0.99, r = 0.93, and r = 0.97 r = 0.76 and r = 0.79, respectively, for totT, McT, McF, McV and MP). Bland-Altman analysis showed a small, significant bias and good precision for all the variables, but McT. A sensor-based 5STS evaluation appears to be a promising objective and digitalized measure of MP. This approach could offer a practical alternative to the gold standard methods used to measure MP.

Hospital-associated sarcopenia, acute sarcopenia, and iatrogenic sarcopenia: Prevention of sarcopenia during hospitalization

Sarcopenia can be classified as age-, activity-, nutrition-, and disease-related. Hospital-associated sarcopenia, acute sarcopenia, and iatrogenic sarcopenia are activity-, nutrition-, and disease-related, not age-related. There is considerable overlap between hospital-associated sarcopenia and acute sarcopenia; however, they are distinct concepts. Some causes of hospital-associated sarcopenia and acute sarcopenia are iatrogenic.

Musculoskeletal Fitness for Identifying Low Physical Function in Older Women

AIMS

This cross-sectional study aimed to analyze the relevance of musculoskeletal fitness for identifying low physical functioning in community-dwelling older women.

METHODS

Sixty-six older women (73.62 ± 8.23 yrs old) performed a musculoskeletal fitness assessment of the upper and lower limbs. A handheld dynamometer was used to evaluate upper-limb muscle strength through a handgrip (HG) test. Lower-limb power and force were assessed from a two-leg countermovement vertical jump (VJ) on a ground reaction force platform. Physical functioning was assessed subjectively using the Composite Physical Function (CPF) questionnaire and objectively by daily step count measured by accelerometry and gait speed/agility assessed by the 8-Foot Up-and-Go (TUG) test. Logistic regressions and ROC curves were carried out to define odds ratios and ideal cutoff values for discriminatory variables.

RESULTS

VJ power showed the ability to identify low physical functioning when evaluated through the CPF (14 W/kg, 1011 W), gait speed/agility (15 W/kg, 800 W), or daily accumulated steps (17 W/kg). Considering that VJ power was normalized for body mass, the increase of 1 W/kg corresponds to a decrease of 21%, 19%, or 16% in the chance of low physical functioning when expressed by these variables, respectively. HG strength and VJ force did not show a capacity to identify low physical functioning.

CONCLUSIONS

The results suggest that VJ power is the only marker of low physical functioning when considering the three benchmarks: perception of physical ability, capacity for mobility, and daily mobility.

Imaging Techniques to Determine Degree of Sarcopenia and Systemic Inflammation in Advanced Renal Cell Carcinoma

PURPOSE OF REVIEW

The purpose of this review is to provide an up-to-date understanding regarding the literature on sarcopenia and inflammation as prognostic factors in the context of renal cell carcinoma (RCC).

RECENT FINDINGS

Sarcopenia is increasingly recognized as a prognostic factor in RCC. Emerging literature suggests monitoring quantity of muscle on successive imaging and examining muscle density may be additionally informative. Inflammation has prognostic ability in RCC and is also considered a key contributor to development and progression of both RCC and sarcopenia. Recent studies suggest these two prognostic factors together may provide additional prognostic ability when used in combination. Ongoing developments include quality control regarding sarcopenia research and imaging, improving understanding of muscle loss mechanisms, and enhancing clinical incorporation of sarcopenia via improving imaging analysis practicality (i.e., artificial intelligence) and feasible biomarkers. Sarcopenia and systemic inflammation are complementary prognostic factors for adverse outcomes in patients with RCC. Further study on high-quality sarcopenia assessment standardization and expedited sarcopenia assessment is desired for eventual routine clinical incorporation of these prognostic factors.

Anthropometric equations to estimate appendicular muscle mass from dual-energy X-ray absorptiometry (DXA): A scoping review

BACKGROUND

Appendicular skeletal muscle mass (ASM) obtained from dual-energy x-ray absorptiometry (DXA) is recommended to quantify sarcopenia, but has limited availability in disadvantaged-income countries, moreover in an epidemiological context. Predictive equations are easier and less costly to apply, but a review of all available models is still lacking in the scientific literature. The objective of this work is to map, with a scoping review, the different proposed anthropometric equations to predict ASM measured by DXA.

METHODS

Six databases were searched without restriction on publication date, idiom, and study type. A total of 2,958 studies were found, of which 39 were included. Eligibility criteria involved ASM measured by DXA, and equations proposed to predict ASM.

RESULTS

predictive equations (n = 122) were gathered for 18 countries. The development phase involves sample size, coefficient of determination (r²), and a standard error of estimative (SEE) varying between 15 and 15,239 persons, 0.39 and 0.98, 0.07 and 3.38 kg, respectively. The validation phase involves a sample size, accuracy, and a SEE between 15 and 3,003 persons, 0.61 and 0.98, 0.09 and 3.65 kg, respectively.

CONCLUSIONS

The different proposed predictive anthropometric equations of ASM DXA were mapped, including validated pre-existing equations, offering an easy-to-use referential article for clinical and research applications. It is necessary to propose more equations for other continents (Africa and Antarctica) and specific health-related conditions (e.g., diseases), once the equations can only have sufficient validity and accuracy to predict ASM generally when applied to the same population.