Pitfalls in the measurement of muscle mass: a need for a reference standard

Artificial intelligence applications and aging (1995-2024): Trends, challenges, and future directions in frailty research

BACKGROUND

Frailty, a significant predictor of adverse health outcomes, has become a focal point of research, particularly with the advent of artificial intelligence (AI) technologies. This study aimed to provide a comprehensive bibliometric analysis of research trends in AI and frailty to map conceptual developments, collaborations, and emerging themes in the field.

METHODS

A systematic search was conducted using the Scopus database employing a comprehensive set of keywords related to AI and frailty. The search was refined to include only original articles in English, yielding 1213 documents. Data extraction was performed in October 2024 and exported in the CSV and BibTeX formats. Annual growth trends were analyzed using Microsoft Excel, while VOSviewer and R-package were used for bibliometric analyzes and visualization to identify key contributors, collaborations, and thematic clusters.

RESULTS

The analysis revealed rapid growth in research publications, with AI applications in frailty gaining prominence over the past decade. Thematic clusters highlight areas such as predictive modeling, machine learning applications, and geriatric care innovations. The United States, United Kingdom, and Italy emerged as leading contributors to publications and collaborations. The key topics included prediction models, dementia, sarcopenia, and rehabilitation. This bibliometric study underscores the increasing integration of AI into frailty research, revealing key trends, collaborative networks, and emerging areas of focus.

CONCLUSION

These findings can guide future research, foster collaborations, and enhance the application of AI technologies to improve frailty assessment and management.

Association of sarcopenia with all-cause and cause-specific mortality in cancer patients: development and validation of a 3-year and 5-year survival prediction model

BACKGROUND

Sarcopenia is a clinicopathological condition characterized by a decrease in muscle strength and muscle mass, playing a crucial role in the prognosis of cancer. Therefore, this study aims to investigate the association between sarcopenia and both all-cause mortality and cancer-specific mortality among cancer patients. Furthermore, we plan to develop risk prediction models using machine learning algorithms to predict 3-year and 5-year survival rates in cancer patients.

METHOD

This study included 1095 cancer patients from the National Health and Nutrition Examination Survey (NHANES) cohorts spanning 1999-2006 and 2011-2014. Initially, we used the Least Absolute Shrinkage and Selection Operator (LASSO)-Cox regression models for feature selection. Subsequently, we employed multivariable Cox regression models to investigate the association between sarcopenia and all-cause and cancer-specific mortality in cancer patients. We developed five machine learning algorithms, including Support Vector Machine (SVM), Logistic Regression (LR), Random Forest (RF), LightGBM, and XGBoost, to predict 3-year and 5-year survival rates and to perform risk stratification.

RESULTS

The multivariable COX regression model showed sarcopenia significantly increases the risk of all-cause mortality (HR = 1.33, 95%CI:1.05, 1.70, P = 0.0194) and cancer-specific mortality (HR = 1.67, 95%CI:1.09, 2.55, P = 0.0176) in cancer patients. Among the five machine learning algorithms developed, the LightGBM model demonstrated strong performance in the 3-year and 5-year survival prediction tasks, making it the optimal model selection. Decision curve analysis and Kaplan-Meier curves further confirmed our model's ability to identify high-risk individuals effectively.

CONCLUSIONS

Sarcopenia significantly increases the risk of mortality in cancer patients. We developed a survival prediction model for cancer patients that effectively identifies high-risk individuals, thereby providing a foundation for personalized survival assessment.

The skeletal muscle mass index is a predictor for all-cause mortality in US adults with type 2 diabetes or pre-diabetes

AIMS

To investigate the relationship between the skeletal muscle mass index (SMI) with all-cause mortality in patients with type 2 diabetes mellitus (T2DM) or pre-diabetes (pre-DM) among American adults.

METHODS

This study included 3684 patients with T2DM or pre-DM from the National Health and Nutrition Examination Survey 2011-2018.

RESULTS

Our study revealed an inverse J-shaped relationship between the SMI with all-cause mortality in US adults with T2DM or pre-DM. We determined the inflection points for all-cause mortality in patients with T2DM or pre-DM were 9.07 kg/m2 in males and 7.82 kg/m2 in females. In men, the all-cause mortality decreased by approximately 72 % (HR, 0.28; 95 % CI, 0.09-0.93) for each unit increased in the SMI below the inflection point. In women, all-cause mortality was reduced by 60 % (HR, 0.40; 95 % CI, 0.16-0.91) for each unit increased in SMI below the threshold. A reverse J-shaped SMI-mortality association emerged in patients with T2DM, contrasting with a U-shaped pattern in pre-DM individuals.

CONCLUSIONS

An inverse J-shaped association was observed between the SMI with all-cause mortality in in US adults with T2DM or pre-DM. SMI is a valuable tool for predicting all-cause mortality in patients with T2DM or pre-DM.

Anti-sarcopenic effect of leucine-enriched branched-chain amino acid supplementation among elderly chronic kidney disease patients: a double-blinded randomized controlled trial

BACKGROUND

Leucine, a branched-chain amino acid (BCAA), is an effective nutritional strategy to enhance skeletal muscle mass in aging populations. This study aimed to evaluate the effects of oral leucine-enriched BCAA supplementation on muscle mass, muscle synthesis biomarkers, and physical performance in elderly patients with chronic kidney disease (CKD).

METHODS

A randomized controlled trial was conducted among CKD patients aged over 65 years. The participants were randomly assigned to receive either oral mixed BCAA supplementation (60% leucine, 4.5 g/day; 20% valine, 1.5 g/day; 20% isoleucine, 1.5 g/day) (N = 29) or a placebo (N = 26) for 12 weeks. Muscle mass, serum insulin-like growth factor 1 (IGF-1), and myostatin levels were measured at baseline and after 12 weeks. A 3-day food record was reviewed by a dietitian, and functional capacity was assessed using handgrip and 6-min walk tests.

RESULTS

Fifty-five patients (mean age 75.4 ± 5.2 years) were enrolled. Daily protein and calorie intake were comparable between groups. At study conclusion, lean muscle mass significantly increased in the leucine group compared to placebo (0.4 kg [95% CI 0.1-0.7] vs. - 0.2 kg [95% CI - 0.6-0.2], P = 0.010). A significant difference in the percentage change in muscle mass was also observed (1.0 ± 1.8% vs. - 0.5 ± 2.6%, P = 0.014). No significant differences were found in muscle strength, serum myostatin, IGF-1, or adverse events.

CONCLUSIONS

Leucine-enriched BCAA supplementation for 12 weeks significantly increased muscle mass but did not impact biomarkers of muscle activity or functional capacity in elderly CKD patients.

CLINICAL TRIAL REGISTRATION

TCTR20200314003.

Identification of Target Body Composition Parameters by Dual-Energy X-Ray Absorptiometry, Bioelectrical Impedance, and Ultrasonography to Detect Older Adults With Frailty and Prefrailty Status Using a Mobile App in Primary Care Services: Descriptive Cross-Sectional Study

Background

Frailty syndrome in older adults represents a significant public health concern, characterized by a reduction in physiological reserves and an increased susceptibility to stressors. This can result in adverse health outcomes, including falls, hospitalization, disability, and mortality. The early identification and management of frailty are essential for improving quality of life and reducing health care costs. Conventional assessment techniques, including dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), and muscle ultrasound (US), are efficacious but frequently constrained in primary care settings by financial and accessibility limitations.

Objective

The aim of this study is to analyze the differences in anthropometric characteristics, physical function, nutritional status, cognitive status, and body composition among older adults identified as frail, prefrail, or robust in primary care services using the PowerFrail mobile app. Furthermore, the study assesses the predictive capacity of body composition variables (whole-body phase angle [WBPhA] via BIA, US-measured rectus femoris muscle thickness, and DXA-derived lean mass) in identifying frailty and evaluates their feasibility for implementation in primary care.

Methods

A descriptive cross-sectional study was conducted with 94 older adult participants aged between 70 and 80 years, recruited through the Andalusian Health Service in Spain. Frailty status was classified using the PowerFrail App, which integrates muscle power assessment and provides personalized physical activity recommendations. Body composition was measured using WBPhA (BIA), muscle US, and DXA. Statistical analyses included 1-way ANOVA for group comparisons, logistic regression to investigate associations, and receiver operating characteristic curve analysis to evaluate the predictive accuracy of the body composition measures.

Results

Participants were categorized into frail (n=28), prefrail (n=33), and robust (n=33) groups. All body composition measures exhibited high specificity in detecting frailty, with varying sensitivity. Unadjusted US showed the highest specificity but low sensitivity (10.7%). WBPhA and right leg lean mass (LeanM RL) demonstrated significant predictive capabilities, especially when adjusted for age and sex, with area under the curve values ranging from 0.678 to 0.762. The adjusted LeanM RL model showed a good balance between sensitivity (35.7%) and specificity (93.9%; P=.045), indicating its potential as a reliable frailty predictor. These findings are consistent with previous research emphasizing the importance of muscle mass and cellular health in frailty assessment.

Conclusions

Body composition variables, particularly WBPhA, LeanM RL, and US, are effective predictors of frailty in older adults. The PowerFrail mobile app, combined with advanced body composition analysis, offers a practical and noninvasive method for early frailty detection in primary care settings. Integrating such technological tools can enhance the early identification and management of frailty, thereby improving health outcomes in the aging population.

Association of muscularity status with clinical and physical function outcomes in critically ill patients with COVID-19: A systematic review and meta-analysis

Pre-coronavirus disease 2019 (COVID-19) critical care research underscored the importance of muscularity on patient outcomes. This study investigates the association between skeletal muscle mass and quality with clinical and physical function outcomes in critically ill patients with COVID-19. We systematically searched MEDLINE, EMBASE, and CINAHL from database inception to April 24, 2024, for studies using objective methods to evaluate muscularity in critically ill adults with COVID-19, without language restrictions. Co-primary outcomes were overall mortality and muscle strength. Random-effect meta-analyses were performed in RevMan 5.4.1. We included 20 studies (N = 1818), assessing muscularity via computed tomography (twelve studies), ultrasound (seven studies), and bioelectrical impedance analysis (one study); none had low risk of bias. In analyses of high vs low muscularity, high muscle mass was significantly associated with lower overall mortality (nine studies; risk ratio = 0.74; 95% CI, 0.57-0.98; P = 0.03). When muscularity was analyzed as a continuous variable, COVID-19 survivors had higher skeletal muscle area (SMA) (13 studies; mean difference [MD] = 1.18; 95% CI, 0.03-2.33; P = 0.05) confirmed by sensitivity analysis using standardized MD (0.23, 95% CI 0.05-0.42, P = 0.01) and significantly higher muscle quality (five studies; standardized MD = 0.45; 95% CI, 0.20-0.70; P = 0.0004). Muscle strength findings were inconsistent: one study showed significant correlations between muscle strength with muscle mass parameters (r = 0.365-0.375, P < 0.001) whereas another found no association. In critically ill adults with COVID-19, high muscle mass was associated with lower mortality risk. Survivors had significantly higher SMA and muscle quality. Findings on physical function outcomes remain inconclusive (PROSPERO ID: CRD42022384155).

Study on the comorbid mechanisms of sarcopenia and late-life depression

The increasing global aging population has brought greater focus to age-related diseases, particularly muscle-brain comorbidities such as sarcopenia and late-life depression. Sarcopenia, defined by the gradual loss of muscle mass and function, is notably prevalent among older individuals, while late-life depression profoundly affects their mental health and overall well-being. Epidemiological evidence suggests a high co-occurrence of these two conditions, although the precise biological mechanisms linking them remain inadequately understood. This review synthesizes the existing body of literature on sarcopenia and late-life depression, examining their definitions, prevalence, clinical presentations, and available treatments. The goal is to clarify the potential connections between these comorbidities and offer a theoretical framework for the development of future preventive and therapeutic strategies.

Assessing bone and muscle health and their association in a Mongolian population aged 40 and older: a pioneering observational study

This study in Mongolia reveals that weaker grip strength and higher sarcopenia risk are linked to greater fracture risk and lower bone density. It highlights the crucial interplay between muscle and bone health, emphasizing the need for integrated musculoskeletal assessments to prevent fractures, especially in aging populations.

BACKGROUND

Research on the relationship between bone and muscle health in low- and middle-income countries, particularly Central Asia, remains limited.

OBJECTIVES

To explore the correlation between muscle and bone health and to estimate the FRAX risk for major osteoporotic fractures (MOF) and hip fractures in the Mongolian population, stratified by age and sex.

METHODS

A cross-sectional study was conducted in Ulaanbaatar and regional Mongolia from May to August 2024. Handgrip strength, sarcopenia risk (SARC-F) and bone mineral density using peripheral DXA (BMD T-score) were assessed. Fracture risks were estimated using the FRAX model.

RESULTS

Participants (n = 857; median age, 52 years; 53.0% women) had a median grip strength of 28 kg and a median BMD T-score of - 1.9. Most (69.5%) were at low sarcopenia risk (SARC-F < 4). SARC-F was moderately correlated with FRAX scores for MOF and hip fractures (r ≈ 0.27, p < 0.001) while grip strength was negatively correlated with FRAX scores(r =  - 0.24, p < 0.001). Grip strength positively correlated with BMD T-scores (r = 0.22, p < 0.001). Fracture risks increased with age, with women showing higher rates than men. Higher sarcopenia risk (SARC-F ≥ 4) was associated with lower BMD and increased fracture risk. Lower grip strength (< 18 kg for women, < 28 kg for men) was linked to higher fracture risk and lower BMD.

CONCLUSIONS

This study highlights the interconnected nature of muscle and bone health in the Mongolian population, demonstrating that lower grip strength and higher sarcopenia risk are significantly associated with increased fracture risk and reduced bone density. These findings underscore the importance of integrated strategies for musculoskeletal health assessment and fracture prevention, particularly in aging populations.

The impact of immature granulocytes on the outcome of patients with decompensated cirrhosis

BACKGROUND

Higher immature granulocyte levels have a predictive role in several clinical conditions, although data concerning cirrhosis are scarce. Reduced muscle mass is a known factor affecting the outcome of these patients. The aim of the study was to evaluate the association of immature granulocytes with muscle mass and their role in predicting the outcome (survival, death or liver transplantation) in patients with stable decompensated cirrhosis.

METHODS

We prospectively studied 210 patients with decompensated cirrhosis awaiting liver transplantation. Their clinical and laboratory characteristics were recorded, including complete blood count with immature granulocyte count and immature granulocyte percentage. The severity of liver disease was evaluated by estimating the Child-Turcotte-Pugh and MELD-sodium scores. Dual energy X-ray absorptiometry was used to quantify the total and regional lean mass, while mid-arm muscle circumference was used for the evaluation of upper limb muscle mass.

RESULTS

Immature granulocyte percentage was proved to be the only factor independently associated with transplant-free survival (Hazard Ratio: 1.98, 95% confidence interval [1.03-3.81], p = .04). Stratification of our cohort based on the best discriminative cut-off values of immature granulocyte count and percentage revealed significant differences in the outcome based on Kaplan-Meier curves, while immature granulocyte count and percentage were significantly associated with parameters of body composition.

CONCLUSIONS

Higher immature granulocyte count and percentage have a significant prognostic role and are associated with worse outcome in patients with stable decompensated cirrhosis.

Bone and muscle mass characteristics in patients with gastroenteropancreatic neuroendocrine neoplasms

BACKGROUND

Neuroendocrine neoplasms (NEN) are rare tumors arising from neuroendocrine cells most commonly in the gastrointestinal-tract. In recent years, advancements in therapeutics have increased survival rates in patients with NEN leading to a greater clinical burden compared to the general population.

METHODS

The aim of this single-center case-control study was to investigate the incidence of low bone mass and changes in body composition in adult patients diagnosed with gastroenteropancreatic neuroendocrine tumors (GEPNET). Enrolled participants underwent measurements of bone mineral density (BMD) at the lumbar spine (LS), femoral neck (FN), and total hip (TH) and body composition analysis with calculation of total fat-mass (TFM) and relative skeletal mass index (RSMI), by dual X-ray absorptiometry.

RESULTS

Ninety GEPNET patients (28 with Pancreatic-NET, 20 with small-intestine-NET, 42 with gastric-NET), and 50 age and sex-matched controls were enrolled. The mean disease duration was 5±4.4 years, the majority of patients (54/90) was classified as stage-1, and were not receiving systemic-treatment (76/90). The incidence of osteoporosis/osteopenia was threefold higher in the patients' cohort, compared to controls (OR: 3.17 95% CI 1.16-7.8, p < 0.001). Among NEN patients, gastric-NET had the lowest bone mass, especially in LS. In addition, GEPNET patients demonstrated significantly lower TFM and RSMI, compared to controls (TFM: 31.6 ± 9.6 kg vs. 38.6 ± 6.4 kg, respectively, p = 0.03; RSMI: 6.4 ± 1.1 vs. 8.2 ± 0.6, respectively, p < 0.001). Within our patients' cohort, RSMI was significantly associated with LS-BMD (rho = 0.49, p < 0.001) and TH-BMD (rho = 0.58, p < 0.001), and TFM was associated with TH-BMD (rho = 0.31, p = 0.004).

CONCLUSIONS

Patients with GEPNET even at an early stage exhibit significantly lower bone, muscle and fat mass compared to the non-NET population, highlighting the importance of continuous monitoring of the musculoskeletal system in these patients.

[Ultrasound of muscles for the diagnosis of sarcopenia in patients with inflammatory bowel diseases]

AIM

To assess the muscle mass of patients with inflammatory bowel disease (IBD) using ultrasound.

MATERIALS AND METHODS

102 IBD patients hospitalized in gastroenterology department of Republican Clinical Hospital (Kazan) were involved in the study. Among them, 49% of patients with ulcerative colitis, 51% with Crohn's disease, 10 people made up the control group (CG). The median age in the IBD group was 39.5 [28.5; 50] years, in the CG - 37 [26; 38] years. There were 52 (51%) women in the IBD group and 5 (50%) in the CG group. Patients were examined to assess body mass index (BMI), mid-upper arm circumference (MUAC, cm) and mid-thigh circumference (MTC, cm) of the dominant side; bioimpedance analysis of body composition using the ABC-02 "MEDASS" device; ultrasound examination of muscle thickness at two points on the leading side: ultrasound thickness of the middle of the shoulder (US-MUAC), ultrasound thickness of the middle of the thigh (US-MTC), dynamometry using a wrist dynamometer, assessment of nutritional status.

RESULTS

According to BMI, patients were distributed as follows: normal in 57 (55.9%) patients; deficiency - in 12 (11.8%); overweight - 25 (24.5%); obesity - 8 (7.8%). Median MUAC in women with IBD was 28 [24.9; 31] cm, in CG - 28 [27; 28.5] cm (p>0.05); in men with IBD 29.8 [27; 32] cm, in CG - 33 [31; 34] cm (p<0.05). The median MTC in women with IBD was 54.25 [48.15; 58.10] cm, in CG - 61.5 [56; 67] cm (p<0.05); in men with IBD 48 [46; 51.4] cm, in GC - 54 [53; 54] cm (p<0.05). The median US-MUAC in women with IBD was 19.60 [18.23; 22.84] mm, CG 22.49 [20.41; 22.66] (p>0.05); in men with IBD 26.45 [22.87; 29.24] mm, in CG 21.54 [21.18; 25.13] mm (p>0.05). Median US-MTC in women with IBD was 31.05 [23.21; 37.11] mm, CG 41.30 [35.55; 41.74] mm (p<0.05), in men with IBD 30.90 [25.64; 39.99] mm, in CG 40.67 [39.10; 41.84] (p<0.05). According to the results of bioimpedansometry, the skeletal muscle mass index (SMI) was low in 32% of patients, normal in 65%, and above normal in 3%. US-MUAC correlated with MUAC (r=0.557; p<0.05), with BMI (r=0.448; p<0.05), with SMI (r=0.666; p<0.05). US-MTC correlated with MTC (r=0.505; p<0.05), with BMI (r=0.376; p<0.05), with SMI (r=0.373; p<0.05).

CONCLUSION

In patients with IBD, MTC was lower than in CG. US-MTC in women and men with IBD was lower than in CG, which correlated with MTC, BMI, skeletal muscle mass according to bioimpedance measurements and grip strength according to dynamometry.

The Effect of Creatine Supplementation on Lean Body Mass with and Without Resistance Training

Background/Objectives: Creatine monohydrate (CrM) is considered to be one of the most effective supplements for enhancing lean body mass during resistance training. However, CrM may influence body water content, potentially confounding lean body mass measurements. Therefore, this randomised controlled trial assessed the effect of CrM alone on lean body mass following a supplement wash-in, and when combined with a resistance training program. Methods: Sixty-three (34 females, 29 males, 31 ± 8 years) participants were randomised to supplement with CrM (5 g/day for 13 weeks: wash-in + 12-week resistance training) or serve as a control (received no creatine or placebo). Lean body mass was measured using dual X-ray absorptiometry at baseline, post 7-day wash-in, and post 12 weeks of resistance training. Both groups began the same training program post CrM wash-in. Results: After the 7-day wash-in, the supplement group gained 0.51 ± 1.79 kg more lean body mass than the control group (p = 0.03). Following the wash-in, both groups gained 2 kg after resistance training (p < 0.0001), with no between-group difference in lean body mass growth (p = 0.71). Sex-disaggregated analysis showed that the supplement group, only in females, gained 0.59 ± 1.61 kg more lean body mass than the controls (p = 0.04). There were no group differences in lean body mass growth following resistance training in females (p = 0.10) or males (p = 0.35). Conclusions: A 7-day CrM wash-in increased lean body mass, particularly in females. Thereafter, CrM did not enhance lean body mass growth when combined with resistance training, likely due to its short-term effects on lean body mass measurements. A maintenance dose of higher than 5 g/day may be necessary to augment lean body mass growth.

Examining the Heterogeneity of Exercise Response Among Sedentary Older Adults: A Descriptive Analysis

Background: Significant heterogeneity in individual responses to exercise interventions provides an opportunity to identify individuals for whom modifications or adjunct therapies may be necessary. Here, we explore heterogeneity of exercise response among people with HIV (PWH) versus without HIV (control). Methods: The Exercise for Healthy Aging Study enrolled sedentary older PWH and controls (50-75 years old) for a 24-week aerobic and resistance exercise program. Responder groups were categorized based on minimally clinically important differences for cardiovascular (CV), strength, and lean mass (LM) outcomes. Descriptive statistics were used to examine baseline characteristics of the different groups. Results: 32 PWH and 37 controls (age 58 ± 6.5 years) were enrolled. CV nonresponders were more likely to have HIV infection, a greater comorbidity burden, and lower baseline CV fitness. Strength nonresponders had a lower comorbidity burden and greater strength at baseline. Comorbidities were similar across LM responder groups. CV and LM nonresponders had an increase in inflammatory markers from baseline to week 24 compared to decreased inflammatory markers among CV and LM responders. Conclusion: Lower CV fitness and HIV infection was more prevalent among those with poorer exercise response, suggesting that higher intensity or a prolonged duration of aerobic exercise may be required to overcome blunted CV adaptations particularly among PWH. Associations of CV and LM response with inflammatory markers should be further explored to determine if and when blocking inflammation might enhance exercise responses. Trial Registration: ClinicalTrials.gov identifier: NCT02404792.

Low creatinine to cystatin C ratio is associated with lower muscle volumes and poorer gait speeds in the longitudinal Integrated Women's Health Program cohort

OBJECTIVE

Little is known about the longitudinal associations between creatinine-cystatin C ratios (CCR) with muscle volume and function during the menopausal transition. We investigated the longitudinal relationship of baseline CCR, with muscle volumes measured by magnetic resonance imaging (MRI), and objectively measured muscle strength and physical performance after 6.6-year follow-up.

METHODS

Participants from the Integrated Women's Health Programme (IWHP) cohort (n = 891, baseline mean age 56.2 ± 6.0) who attended both baseline and follow-up visits underwent objectively measured muscle strength and physical performance assessments and MRI. Creatinine to cystatin C ratio was calculated as (creatinine [mg/dL] / cystatin C [mg/L]) and low CCR were those in the lowest tertile (CCR < 8.16). Multivariable regression analyses were used to determine the associations of baseline CCR with muscle volumes and function 6.6 years later.

RESULTS

Baseline low CCR was associated with lower MRI-measured muscle volumes and poorer physical function 6.6 years later. Compared to high CCR group, mean fat-free thigh muscle volume of the low CCR group was 0.350 L lower (95% CI, 0.183-0.518) after adjustment for covariates. Similarly, the low CCR group was associated with 0.029 m/s slower (95% CI, 0.006-0.053) slower mean usual gait and 0.049 m/s slower (95% CI, 0.020-0.078) mean narrow gait speeds. CCR was not associated with handgrip strength and repeated chair stands and one-leg stand tests.

CONCLUSION

Low CCR at baseline was associated with lower fat-free muscle volumes and poorer gait speeds 6.6 years later. The potential of CCR as a predictive biomarker for adverse events related to sarcopenia in midlife women merits further investigation.

Body Composition and Its Outcomes and Management in Multiple Sclerosis: Narrative Review

Background: There is emerging interest in obesity and its prevalence, outcomes, and management in people with multiple sclerosis (MS). Body mass index (BMI) is the traditional marker of obesity in MS, whereas body composition, inclusive of specific body tissue compartments (e.g., fat, bone, and muscle), is often overlooked despite its relevance. Objective: This narrative review (a) underscored the use and utility of dual-energy X-ray absorptiometry (DEXA) as an accurate and reliable measure of body composition; (b) thematically analyzed and synthesized the current evidence regarding body composition (using DEXA); and (c) determined gaps to be addressed in future research. Methods: The structure and reporting of this narrative review followed the guiding criteria outlined in the Scale for the Assessment of Narrative Review Articles (SANRA). The relevant literature for this narrative review was identified via a PubMed search utilizing combined search terms such as 'body composition' and 'multiple sclerosis'. The identified research was then organized by the authors into major themes and sub-themes. The articles described within the narrative review were based on saturation of the identified themes and sub-themes. Results: Three major themes were identified, namely (1) comparison of body composition between people with MS and non-MS controls (2 meta-analyses); (2) examination of the relationships between body composition and a range of outcomes (14 cross-sectional studies); and (3) interventions that report and/or target body composition in MS (11 clinical trials). Conclusions: This narrative review mapped the existing evidence regarding body composition in MS, and posits body composition as a novel, informative, and targeted concept for this population. The narrative review underscores the importance of randomized controlled trials that focus on body composition as a significant and modifiable outcome. Such research could improve the understanding of obesity and poor body composition in MS and identify useful clinical recommendations for diagnosis and management.

The use of portable A-mode ultrasound in appendicular lean mass measurements among older adults: a comparison study with dual-energy X-ray absorptiometry and handgrip strength

BACKGROUND/OBJECTIVES

Strength and muscle mass are key factors for the diagnosis of sarcopenia. The EWGSOP2 recommended using ultrasound (US) as a reliable device to measure muscle mass (MM), but A-mode US still needs to be validated for older adults. This study aimed to evaluate the association between measurements of muscle thickness (MT) by portable A-mode US and, muscle quantity by Dual-Energy X-ray absorptiometry (DXA) in older adults.

METHODS

Cross-sectional study, with 115 participants included. Muscle mass was assessed by DXA and MT of the biceps, triceps, anterior thigh, and calf by A-mode US and handgrip strength by a dynamometer.

RESULTS

The majority were women (n = 96; 83%), 69 ± 6 years. The MT sum (biceps, triceps, thigh, and calf) assessed by the US was not associated with the appendicular lean mass (ALM) assessed by DXA after controlling for sex and age (R2 = 0.524; p = 0.139; effect size = 0.53). The MT sum biceps and triceps was still significantly associated with MM arms/2 even when controlling for sex and age (which were also significant) (R2 = 0.551; p < 0.001; effect size = 0.56). The MT sum thigh and calf was not associated with MM legs/2 in adjusted models (R2 = 0.499; p = 0.688; effect size = 0.51).

CONCLUSIONS

This finding shows that the portable A-mode US may not be an appropriate method for estimating MM in extremities (the sum of arms and legs), but can be appropriate for estimating only MM arms in healthy older adults.

Dual-energy x-ray absorptiometry derived body composition trajectories across adulthood: Reference values and associations with body roundness index and body mass index

BACKGROUND

Population-specific reference values are needed to accurately contextualise age-related changes in body composition. This study aimed to a) establish age- and sex-specific reference values and cut-points for a range of dual-energy x-ray absorptiometry (DXA) derived metrics of lean mass (LM), fat mass (FM) and bone mineral density (BMD), across adulthood in a large adult cohort; and b) determine the association between DXA-derived body composition, body roundness index (BRI), and body mass index (BMI).

METHODS

Cross-sectional data were collected from 10,033 men and women aged from 18 to 92 years. Whole-body DXA scans were performed, and a range of metrics were calculated for LM (total LM, arm LM, leg LM, appendicular lean mass: ALM, skeletal muscle index: SMI), FM (total FM: kg and %, FMI, android to gynoid: A/G ratio) and bone (BMD). Cut-points equivalent to Z-scores of 1.0-2.5 SDs from the mean of a young reference population were established for each body composition metric.

RESULTS

Detailed age- and sex-specific percentile curves were generated using the LMS method. Metrics of LM, central adiposity and BMD were higher in men, compared to women, whereas metrics of general FM accumulation were higher in women, compared to men. In both sexes, all LM metrics remained broadly stable during early and middle adulthood, after which progressively lower quantities were shown, whereas progressively higher FM metrics were shown from early adulthood through to late adulthood. In men, BMD was broadly stable across adulthood, whereas in women, markedly lower BMD was observed from the fifth decade of life. Significantly higher quantities of LM were shown across BMI categories, but not across BRI categories. The BRI was better correlated with FM%, FMI, and A/G ratio, compared to the BMI.

CONCLUSION

The reference values presented herein may support the interpretation of body composition in public health settings and the identification of people who may benefit from intervention to improve musculoskeletal and metabolic health. The BRI better reflects DXA-derived body composition and may provide screening utility beyond that of the BMI.

Cut-off values for the muscle mass indices determined using DXA in healthy Polish adults - a comparison to EWGSOP2 recommendation

BACKGROUND

Muscle mass measurements are vital for predicting health outcomes and diagnosing muscle disorders. This study provides reference data for appendicular lean mass (ALM) and total lean mass (TLM) in healthy Polish adults with normal muscle strength and physical performance as per EWGSOP2 guidelines.

METHODS

The study included healthy volunteers with normal muscle strength and functional status. Lean mass was measured using Hologic Horizon DXA. Mean values of TLM, ALM, fat-free mass (FFM), and indices (TLMI, ALMI, FFMI) were calculated for seven age groups (by decade). Cut-off points equivalent to T-scores of -1 and -2 standard deviations (SDs) below the young adult reference mean (ages 20-39) were determined.

RESULTS

Data from 1,111 participants (328 men, 46.3 ± 20 years; 783 women, 43.7 ± 23 years) were analyzed. In young adults, mean ALM was 28.1 kg (men) and 17.2 kg (women), and ALMI was 8.6 kg/m2 (men) and 6.1 kg/m2 (women). Low muscle mass cut-off points (2 SDs below) were 18 kg and 10.9 kg (ALM) and 6 kg/m2 and 4.3 kg/m2 (ALMI) for men and women, respectively. Men exhibited significantly greater lean mass than women across all age groups (P < 0.001). Lean mass declined with age in both genders, following a nonlinear pattern, except for ALMI in men.

CONCLUSIONS

This study provides the first population-based reference values for ALM and TLM in healthy Polish adults aged 20-89 years, integrating criteria for normal muscle strength and physical performance.

Effect of Exercise and Nutrition Intervention for Older Adults with Impaired Physical Function with Preserved Muscle Mass (Functional Sarcopenia): A Randomized Controlled Trial

Background

Functional sarcopenia is characterized by decreased physical performance and grip strength despite preserved muscle mass. The effectiveness of a program combining exercise and nutritional support-known interventions for individuals with low muscle mass-was evaluated for its impact on older adults with functional sarcopenia.

Methods

An unblinded, parallel-group randomized controlled trial was conducted in a public medical center in a rural Korean community. Eligible older adults with functional sarcopenia were randomized into either the intervention group, receiving a 12-week program of group exercises and nutritional support, or the control group, receiving education on lifestyle management. Outcomes measured included changes in gait speed, grip strength, physical performance, and quality of life indices.

Results

The study enrolled 42 participants, with 21 allocated to each group. Compared with the control group, the intervention group showed significant improvements in the primary outcome of gait speed (mean change (m/s) 0.24 vs 0.00, p<0.001) and secondary outcomes, such as Short Physical Performance Battery scores, grip strength, and quality of life. No significant adverse events were reported.

Conclusion

The 12-week exercise and nutritional intervention significantly enhanced physical performance, grip strength, and quality of life among community-dwelling older adults with functional sarcopenia. This suggests that strategies commonly recommended for sarcopenia, including exercise and nutritional support, are also beneficial for individuals with functional sarcopenia, indicating the potential for broader application of such interventions.

In vivo medical imaging for assessing geroprotective interventions in humans

There is a growing interest in developing drugs with a general geroprotective effect, aimed at slowing down aging. Several compounds have been shown to increase the lifespan and reduce the incidence of age-related diseases in model organisms. Translating these results is challenging, due to the long lifespan of humans. To address this, we propose using a battery of medical imaging protocols that allow for assessments of age-related processes known to precede disease onset. These protocols, based on magnetic resonance imaging, positron emission-, computed-, and optical coherence tomography, are already in use in drug development and are available at most modern hospitals. Here, we outline how an informed use of these techniques allows for detecting changes in the accumulation of age-related pathologies in a diverse set of physiological systems. This in vivo imaging battery enables efficient screening of candidate geroprotective compounds in early phase clinical trials, within reasonable trial durations.

A sarcopenia prediction model based on the calf maximum muscle circumference measured by ultrasound

BACKGROUND

The correlation between calf circumference（CC）and sarcopenia has been demonstrated, but the correlation between calf maximum muscle circumference (CMMC) measured by ultrasound and sarcopenia has not been reported. We aims to construct a predictive model for sarcopenia based on CMMC in hospitalized older patients.

METHODS

This was a retrospective controlled study of patients > 60 years of age hospitalized in the geriatric department of Hunan Provincial People's Hospital. The patients were thoroughly evaluated by questionnaires, laboratory, and ultrasound examinations, including measuring muscle thickness and calf muscle maximum circumference using ultrasound. Patients were categorized into sarcopenia and non-sarcopenia groups according to the consensus for diagnosis of sarcopenia recommended by the Asian Working Group on Sarcopenia 2019 (AWGS2). Independent predictors of sarcopenia were identified by univariate and multivariate logistic regression analyses, and a predictive model was developed and simplified. The prediction performance of the models was assessed using sensitivity, specificity, and area under the curve (AUC) and compared with independent predictors.

RESULTS

We found that patient age, albumin level (ALB), brachioradialis muscle thickness (BRMT), gastrocnemius lateral head muscle thickness (Glh MT), and calf maximum muscle circumference (CMMC) were independent predictors of sarcopenia in hospitalized older patients. The prediction model was established and simplified to Logistic P = -4.5 + 1.4 × age + 1.3 × ALB + 1.6 × BR MT + 3.7 × CMMC + 1.8 × Glh MT, and the best cut-off value of the model was 0.485. The sensitivity, specificity, and AUC of the model were 0.884 (0.807-0.962), 0.837 (0.762-0.911), and 0.927 (0.890-0.963), respectively. The kappa coefficient between this model and the diagnostic criteria recommended by AWGS2 was 0.709.

CONCLUSION

We constructed a sarcopenia prediction model with five variables: age, ALB level, BR MT, Glh MT, and CMMC. The model could quickly predict sarcopenia in older hospitalized patients.

Body composition and aging: cross-sectional results from the INSPIRE study in people 20 to 93 years old

Aging is characterized by several major changes, including altered body composition, which is associated with numerous negative clinical consequences such as sarcopenia, osteoporosis, and frailty. The study is to evaluate body composition parameters depending on age and sex in a population ranging from the young adult to the very old, and to identify break points in the association between body composition and age. In this cross-sectional study, we included the enrolment population of the French INSPIRE-T prospective cohort, accounting for 915 subjects (62% female). Age ranged from 20 to 93 years, median age (years) was 63 (IQR 27). Body composition (lean mass, fat mass, and bone mineral content) was assessed with dual-X-ray absorptiometry (DXA). Different break points in the relationship between age and body composition variables in males and females were identified using a segmented regression analysis adjusted on physical activity, nutritional status, educational level, and comorbidities. Lean mass decreased from the age of 55 years for males (CI 95% 44-66) and 31 years for females (CI 95% 23-39). For fat mass, we observed a trend towards an increase with age for males. For females, we observed an increase with age up to age 75 (CI 95% 62-86), followed by a decreasing trend. In this study, we described the relationship between body composition and age as a function of sex, establishing a foundation for further studies on predictive biomarkers of age-related body composition alteration.

Manual Dexterity in Open-Water Wetsuited Swimmers: A Cohort Crossover Study

PURPOSE

Laboratory studies have demonstrated that manual dexterity decreases with increasing cold, which may adversely affect performance. Dexterity may be impaired by cooling of the hand, cooling of the lower motor neurons, and cognitive impairment. Wetsuits are commonly used in open-water swimming and are mandated in some situations. This study investigates the effects of cold-water wetsuited swimming on dexterity.

METHODS

Five male and 4 female trained swimmers were recruited for this cohort crossover study. Following dual-energy X-ray absorptiometry scans to determine body composition, they swam in a freshwater lake on 7 occasions with water temperatures between 24.5 °C and 8.4 °C. Dexterity was measured preswim and postswim with a "nut-washer-bolt assembly time test" and cognition with a Stroop test. Core and peripheral body temperatures were continuously monitored. Effects were analyzed by linear mixed-model regression.

RESULTS

Pre-post swim difference in time to complete the nut-bolt assembly increased as water temperatures decreased (1.0 s, 95% CI, 0.5-1.5 per 1 °C, P < .0001; R2 = .456), to a maximum of 14.7 seconds (95% CI, 3.3-26.0). This represented a 47.5% increase in assembly time from 24.5 °C to 8.4 °C, which we consider to be of practical significance. Decreased dexterity was associated with decreased forearm and scapular temperature and decreased cognitive function. Body composition did not affect dexterity, cognitive function, or body temperature during swims. Water temperature did not affect swim speed.

CONCLUSIONS

Despite the use of wetsuits, manual dexterity decreased with cold-water swimming. Swimmers, triathletes, and event organizers should consider the implications for safety, performance, and equipment utilization.

Concordance of Freehand 3D Ultrasound Muscle Measurements With Sarcopenia Parameters in a Geriatric Rehabilitation Ward

BACKGROUND

Sarcopenia is a devastating disease for older adults, but it lacks accessible and reliable tools for measuring total appendicular skeletal muscle mass (ASMM). Two-dimensional muscle ultrasound (US) has been developed for its bedside clinical advantages and feasibility but lacks standardization and prediction performance. We previously validated a new 3D-US technique to measure muscle volume (MV) at bedside and applied it in a geriatric rehabilitation setting. Objectives were to analyse the concordance between 3D-US MV and ASMM and compare concordance between 3D-US MV and 2D-US parameters with ASMM.

METHODS

Participants were recruited in a Geriatric rehabilitation ward in Nantes, France, from May to October 2022. Exclusion criteria were as follows: oedema in the lower limbs or recent history of unilateral lower limb damage or stroke. ASMM was measured with bioelectrical impedance analysis; 3D-US and 2D-US acquisitions were performed on three muscles of the right lower limb. Measures of strength (hand grip, knee extension and ankle dorsiflexion) were also recorded. Reliability of 3D-US MV measurements on 10 participants was high (ICC = 0.99). We used Lin's concordance correlation coefficients (CCC) and bias correction factor for agreement between variables and linear regression models for prediction equations.

RESULTS

Fifty-eight participants had an interpretable ASMM of whom 17 (29%) had a diagnosis of sarcopenia. Volumes of TA, RF and VL were all significantly concordant with ASMM measured by BIA (all p values < 0.001), with CCCs respectively of 0.72, 0.61 and 0.60. MV were all significantly concordant with isometric strength (p values < 0.001). Concordance and correlation with ASMM were higher with 3D-US than 2D-US measurements regardless of the muscle. Prediction of ASMM reached an adjusted R2 of 0.8 with tibialis anterior volume, biometrics and 2D measurements.

CONCLUSIONS

This study was the first to use 3D-US in a geriatric setting and develop a model to predict ASMM in very old hospitalized patients. MV measurements with 3D-US proved to be reliable and more concordant with appendicular muscle mass and strength than 2D parameters.

Poor muscle quality: A hidden and detrimental health condition in obesity

Poor muscle quality (MQ) is a hidden health condition in obesity, commonly disregarded and underdiagnosed, associated with poor health-related outcomes. This narrative review provides an in-depth exploration of MQ in obesity, including definitions, available assessment methods and challenges, pathophysiology, association with health outcomes, and potential interventions. MQ is a broad term that can include imaging, histological, functional, or metabolic assessments, evaluating beyond muscle quantity. MQ assessment is highly heterogeneous and requires further standardization. Common definitions of MQ include 1) muscle-specific strength (or functional MQ), the ratio between muscle strength and muscle quantity, and 2) muscle composition (or morphological MQ), mainly evaluating muscle fat infiltration. An individual with obesity might still have normal or higher muscle quantity despite having poor MQ, and techniques for direct measurements are needed. However, the use of body composition and physical function assessments is still limited in clinical practice. Thus, more accessible techniques for assessing strength, muscle mass, and composition should be further explored. Obesity leads to adipocyte dysfunction, generating a low-grade chronic inflammatory state, which leads to mitochondrial dysfunction. Adipocyte and mitochondrial dysfunction result in metabolic dysfunction manifesting clinically as insulin resistance, dyslipidemia, and fat infiltration into organs such as muscle, which in excess is termed myosteatosis. Myosteatosis decreases muscle cell function and insulin sensitivity, creating a vicious cycle of inflammation and metabolic derangements. Myosteatosis increases the risk of poor muscle function, systemic metabolic complications, and mortality, presenting prognostic potential. Interventions shown to improve MQ include nutrition, physical activity/exercise, pharmacology, and metabolic and bariatric surgery.

Sex-specific associations between body composition and depression among U.S. adults: a cross-sectional study

BACKGROUND

Depression presents sexual dimorphism, and one important factor that increases the frequency of depression and contributes to sex-specific variations in its presentation is obesity. The conventional use of Body Mass Index (BMI) as an indicator of obesity is inherently limited due to its inability to distinguish between fat and lean mass, which limits its predictive utility for depression risk. Implementation of dual-energy X-ray absorptiometry (DXA) investigated sex-specific associations between body composition (fat mass, appendicular lean mass) and depression.

METHODS

Data from the NHANES cycles between 2011 and 2018 were analyzed, including 3,637 participants (1,788 males and 1,849 females). Four body composition profiles were identified in the subjects: low adiposity-low muscle (LA-LM), low adiposity-high muscle (LA-HM), high adiposity-low muscle (HA-LM) and high adiposity-high muscle (HA-HM). After accounting for confounding variables, the associations between fat mass index (FMI), appendicular skeletal muscle mass index (ASMI), body fat percentage (BFP), body composition phenotypes, and depression risk were assessed using restricted cubic spline (RCS) curves and multivariable logistic regression models. We further conducted interaction analyses for ASMI and FMI in females.

RESULTS

RCS curves indicated a U-shaped relationship between ASMI and the risk of depression in males. Logistic regression analysis revealed that in males, the second (OR = 0.43, 95%CI:0.22-0.85) and third (OR = 0.35, 95%CI:0.14-0.86) quartile levels of ASMI were significantly negatively associated with depression risk. In females, increases in BFP (OR = 1.06, 95%CI:1.03-1.09) and FMI (OR = 1.08, 95% CI:1.04-1.12) were significantly associated with an increased risk of depression. Additionally, compared to females with a low-fat high-muscle phenotype, those with LA-LM (OR = 3.97, 95%CI:2.16-7.30), HA-LM (OR = 5.40, 95%CI:2.34-12.46), and HA-HM (OR = 6.36, 95%CI:3.26-12.37) phenotypes were more likely to develop depression. Interestingly, further interaction analysis of ASMI and FMI in females revealed an interplay between height-adjusted fat mass and muscle mass (OR = 4.67, 95%CI: 2.04-10.71).

CONCLUSION

The findings demonstrate how important it is to consider body composition when estimating the risk of depression, particularly in females. There is a substantial correlation between the LA-LM, HA-LM, and HA-HM phenotypes in females with a higher prevalence of depression. It is advised to use a preventative approach that involves gaining muscle mass and losing fat.

Sarcopenia and immune-mediated inflammatory diseases: Evaluating causality and exploring therapeutic targets for sarcopenia through Mendelian randomization

BACKGROUND

An increasing body of evidence has revealed the association between immune-mediated inflammatory diseases (IMIDs) and sarcopenia. However, a genetically direct causality between IMIDs and sarcopenia remains elusive.

METHODS

To investigate the relationship between IMIDs and sarcopenia-related traits and identify potential therapeutic targets, a Mendelian randomization (MR) was performed. We collected publicly available genome-wide association studies (GWAS) data for seven common IMIDs, including systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD), Crohn's disease (CD), ulcerative colitis (UC), psoriasis (PSO), ankylosing spondylitis (AS), and rheumatoid arthritis (RA). Additionally, summary-level GWAS data for sarcopenia-related traits, including appendicular lean mass (ALM), left-hand grip strength, and right-hand grip strength were collected. To search for therapeutic targets, we used two types of genetic instruments to proxy the exposure of druggable genes, including genetic variants within or nearby drug targets and expression quantitative trait loci (eQTLs) of drug targets. Two-sample MR and summary-data-based MR (SMR) were used to calculate effect estimates, and sensitivity analyses were implemented for robustness. Drug tractability, gene enrichment analysis, and protein-protein interaction (PPI) analysis were used to validate the biological and clinical significance of the selected drug targets.

RESULTS

The two-sample MR analysis indicated the existence of casual associations between IMIDs and sarcopenia-related traits in the overall and sex-stratified populations. In particular, PSO had causal effects on decreased ALM, which showed significance in all six MR analysis tests with directional consistency in the overall population. Grounded in this robust association, HLA-DRB5, HLA-DRB1, and AGER were identified as potential therapeutic targets for ALM decline by drug target MR and further confirmed by SMR analysis. These genes were associated with therapeutic agents currently undergoing evaluations in clinical trials. Gene enrichment and PPI analysis indicated a strong association of these genes with immune functions.

CONCLUSIONS

This MR study contributes novel genetic evidence supporting the causal link between IMIDs and sarcopenia, with a particular emphasis on the association between PSO and decreased ALM. Additionally, AGER, HLA-DRB1, and HLA-DRB5 emerge as potential therapeutic targets for ALM decline.

Risk Prediction Models for Sarcopenia in Dialysis Patients: A Systematic Review

Nowadays, numerous studies have developed risk prediction models for sarcopenia in dialysis patients. However, the quality and performance of these models have not been integrated. The purpose of our study is to provide a comprehensive overview of the current risk prediction models for sarcopenia in dialysis patients and to offer a reference for the development of high-quality prediction models. Ten electronic databases were searched from inception to March 8, 2024. Two researchers independently assessed the risk of bias and applicability of the studies, and used Revman, 5.4, software to conduct a meta-analysis of common predictors in the models. A total of 12 studies described 13 risk prediction models for dialysis patients with sarcopenia. In dialysis patients, the prevalence of sarcopenia ranged from 6.60% to 63.73%. The area under curve (AUC) of the 13 models ranged from 0.776 to 0.945. Only six models (AUC ranging from 0.73 to 0.832) were internally validated, while two were externally evaluated (AUC ranging from 0.913 to 0.955). Most studies had a high risk of bias. The most common effective predictors in the models were age, body mass index, muscle circumference, and C-reactive protein. Our study suggests that developing a prediction model for the onset of sarcopenia in dialysis patients requires a rigorous design scheme, and future verification methods will necessitate multicenter external validation.

Individual and combined effects of muscle strength and visceral adiposity on incident prediabetes and type 2 diabetes in a longitudinal cohort of midlife Asian women

AIM

To investigate the independent and combined effects of muscle strength and visceral adiposity on prediabetes and type 2 diabetes incidence among midlife women.

MATERIALS AND METHODS

In this prospective study of midlife women (mean age 56.4 years), visceral adiposity, defined as visceral adipose tissue (VAT) >131 cm2 measured by dual energy X-ray absorptiometry, and poor combined muscle strength, defined as handgrip strength <18 kg and/or five-time repeated chair stand test performance ≥12 s, were determined at baseline between 2014 and 2016. After 6.6 years, the effects of VAT and muscle strength on risk of incident prediabetes (fasting blood glucose 5.6-6.9 mmol/L) and type 2 diabetes (fasting blood glucose levels ≥7 mmol/L, medication use, or physician diagnosis) were examined using modified Poisson regression analysis.

RESULTS

Among the 733 initially normoglycaemic participants, 150 (20.5%) developed prediabetes or type 2 diabetes. Women with both poor combined muscle strength and high VAT had the highest risk for both prediabetes and type 2 diabetes (adjusted relative risk [aRR] 2.63, 95% confidence interval [CI] 1.81-3.82). In comparison, high VAT alone increased risk by 1.78-fold (95% CI 1.12-2.84). Stratification analyses showed that among women with low muscle strength, high VAT demonstrated increased risks of prediabetes and type 2 diabetes (aRR 2.84, 95% CI 1.95-4.14) compared to those with normal strength (aRR 1.66, 95% CI 1.04-2.65).

CONCLUSIONS

Low combined muscle strength with high VAT poses a greater risk for the development of prediabetes and type 2 diabetes than high VAT alone. Muscle strengthening should be promoted alongside weight loss in diabetes prevention.

Comparison of the ability between dual-energy X-ray absorptiometry and bioelectrical impedance analysis for diagnosing low skeletal muscle mass and sarcopenia in patients with chronic liver disease

BACKGROUND AND AIM

Sarcopenia and osteoporosis adversely impact the clinical outcomes of patients with chronic liver disease (CLD). The Japan Society of Hepatology (JSH) sarcopenia criteria utilize bioelectrical impedance analysis (BIA) for assessing muscle mass rather than dual-energy X-ray absorptiometry (DXA), which can simultaneously diagnose these comorbidities. We investigated the correlations and interchangeability between the appendicular skeletal muscle mass index (ASMI) values determined using BIA and DXA and evaluated the diagnostic ability of DXA for sarcopenia and osteosarcopenia in patients with CLD.

METHODS

This cross-sectional study included 173 patients with CLD. Sarcopenia was defined as low ASMIBIA according to the JSH and Asian Working Group for Sarcopenia (AWGS) criteria (ASMIBIA cutoff) or low ASMIDXA according to the AWGS criteria (ASMIDXA cutoff) and low handgrip strength. For women, a provisional cutoff value was set for ASMIDXA using the ASMIBIA cutoff (ASMIDXA-altered cutoff).

RESULTS

We found that ASMIBIA and ASMIDXA were significantly correlated (r = 0.921; P < 0.001). The Bland-Altman plots demonstrated substantial agreement between ASMIBIA and ASMIDXA, with a mean difference of 0.0116 kg/m2. The prevalence rates of sarcopenia and osteosarcopenia diagnosed using the ASMIBIA cutoff were 26.0% and 17.3%, respectively. The kappa coefficients for the prevalence of sarcopenia and osteosarcopenia were 0.759 and 0.775 between ASMIBIA cutoff and ASMIDXA cutoff and 0.780 and 0.806 between ASMIBIA cutoff and ASMIDXA-altered cutoff, respectively.

CONCLUSIONS

The utilization of DXA can facilitate the comprehensive assessment and management of musculoskeletal comorbidities in patients with CLD.

Dental Functional Status as a Possible Risk Factor of Sarcopenia: A Computed Tomography-Based Study

BACKGROUND

Functional dentition may be associated with sarcopenia by affecting chewing activity.

OBJECTIVES

The objective of this study is to determine the sarcopenia status of participants using computed tomography (CT)-based data and to investigate the association of sarcopenia with functional dentition, as well as denture condition.

METHODS

The study included 309 patients. The number of teeth was recorded. Functional dentition was evaluated based on the following parameters: (1) ≥ 1 tooth in the maxilla and mandible; (2) ≥ 10 teeth in each arch; (3) the presence of 12 anterior teeth; (4) 3-4 premolar posterior occlusal pairs (POPs) and (5) ≥ 1 molar POP bilaterally. The denture condition was also evaluated. CT-based assessment of sarcopenia was performed via measurement of the psoas muscle area at the level of the L3 vertebra and its hounsfield unit (HU) radiodensity on non-contrast-enhanced images. HU average calculation (HUAC), which is an imaging marker of sarcopenia, was performed. Gender-specific quartiles were then generated, and the lowest quartile of HUAC scores within each gender group was set as the cut-off point.

RESULTS

A total of 76 (24.5%) of the patients had sarcopenia, and 233 (75.5%) did not have sarcopenia. The mean number of teeth in the sarcopenia group was 17.12 ± 8.39, compared to 22.24 ± 6.72 in those without sarcopenia (p < 0.001). The relationship between functional dentition and sarcopenia was also significant. There was a positive relationship between ill-fitting dentures and sarcopenia (p < 0.001).

CONCLUSIONS

This unique perspective of the study contributes to the existing knowledge regarding the role of tooth loss in sarcopenia, highlighting the importance of functional occlusion.

Differences in lean mass and sarcopenia between individuals with Alzheimer's disease and those without dementia: A systematic review and meta-analysis of observational studies

BACKGROUND

Studies have observed that individuals with Alzheimer's disease (AD) tend to have lower lean mass and higher rates of sarcopenia.

OBJECTIVE

This review aims to assess differences in lean mass, sarcopenia, and its components between individuals with AD and those without dementia (WD).

METHODS

Searches were conducted in the Medline, Web of Science, Embase, Scopus and Latin American and Caribbean Health Scientific Literature. Observational studies comparing lean mass, sarcopenia, and its components in the populations of interest were included. We used the Joanna Briggs Institute (JBI) scale to assess methodological quality. Mean differences (MD) and standardized mean differences were calculated for the meta-analyses.

RESULTS

Four studies with 2035 individuals found that those with AD had significantly lower upper and lower limb lean mass, and skeletal muscle mass index compared to WD individuals. AD individuals also had a higher sarcopenia prevalence (41.33% versus 20.66%) and significant reductions in handgrip strength, lower limb muscle strength, and gait speed compared to WD individuals. The JBI scale analysis showed high agreement among the studies (k = 1.00, p = 0.046).

CONCLUSIONS

Individuals with AD have lower lean mass, higher rates of sarcopenia, and reduced muscle function compared to those without dementia. While the results suggest the need for early screening programs and integrated therapeutic interventions to improve clinical outcomes and quality of life for individuals with AD, it is important to consider that biases inherent in observational studies may compromise the quality of the evidence. Therefore, further research, preferably clinical trials, is needed to confirm these associations.

Comparison of bioelectrical impedance analysis and dual-energy X-ray absorptiometry for the diagnosis of sarcopenia in the older adults with metabolic syndrome: equipment-specific equation development

OBJECTIVE

Metabolic syndrome (MetS) and sarcopenia together pose significant health risks, increasing frailty, falls, and fractures in older adults. This study compared muscle mass measurements obtained using two different dual-energy X-ray absorptiometry (DXA) machines and bioelectrical impedance analysis (BIA), and evaluated the accuracy of these measurements in these older adults.

METHODS

In this prospective multicenter cohort study, patients aged ≥ 65 years with MetS had their muscle mass assessed using both BIA and DXA. Two DXA devices, Hologic Horizon and GE Lunar Prodigy, were used as clinical standards for sarcopenia diagnosis. Statistical analyses generated equations for transforming BIA results to match those from DXA, enhancing comparability.

RESULTS

Participants had a mean age of 73.2 ± 5.3 years. The mean appendicular skeletal muscle mass (ASM) measured by BIA and DXA was 19.7 ± 3.1 kg (BIA) and 18.1 ± 2.9 kg (DXA) for males, and 13.7 ± 2.2 kg (BIA) and 12.6 ± 1.8 kg (DXA) for females. Device-specific equations were developed to estimate DXA-measured ASM based on BIA results. These equations are presented for all participants and for each DXA device, highlighting significant differences in prediction models between the two DXA machines.

CONCLUSION

The study developed device-specific equations for sarcopenia diagnosis in older adults with MetS, highlighting substantial differences between Hologic and GE Lunar devices. While BIA may offer a more accessible alternative to DXA, the variation in prediction formulas underscores the need for standardized equipment to ensure consistency in sarcopenia diagnosis.

Obesity and Metabolic Disease Impair the Anabolic Response to Protein Supplementation and Resistance Exercise: A Retrospective Analysis of a Randomized Clinical Trial with Implications for Aging, Sarcopenic Obesity, and Weight Management

BACKGROUND

Anabolic resistance accelerates muscle loss in aging and obesity, thus predisposing to sarcopenic obesity.

METHODS

In this retrospective analysis of a randomized clinical trial, we examined baseline predictors of the adaptive response to three months of home-based resistance exercise, daily physical activity, and protein-based, multi-ingredient supplementation (MIS) in a cohort of free-living, older males (n = 32).

RESULTS

Multiple linear regression analyses revealed that obesity and a Global Risk Index for metabolic syndrome (MetS) were the strongest predictors of Δ% gains in lean mass (TLM and ASM), LM/body fat ratios (TLM/%BF, ASM/FM, and ASM/%BF), and allometric LM (ASMI, TLM/BW, TLM/BMI, ASM/BW), with moderately strong, negative correlations to the adaptive response to polytherapy r = -0.36 to -0.68 (p < 0.05). Kidney function, PA level, and chronological age were only weakly associated with treatment outcomes (p > 0.05). Next, we performed a subgroup analysis in overweight/obese participants with at least one other MetS risk factor and examined their adaptive response to polytherapy with two types of protein-based MIS (PLA; collagen peptides and safflower oil, n = 8, M5; whey/casein, creatine, calcium, vitamin D3, and fish oil, n = 12). The M5 group showed greater improvements in LM (ASM; +2% vs. -0.8%), LM/body fat ratios (ASM/FM; +3.8% vs. -5.1%), allometric LM (ASM/BMI; +1.2% vs. -2.5%), strength (leg press; +17% vs. -1.4%), and performance (4-Step-Stair-Climb time; -10.5% vs. +1.1%) vs. the PLA group (p < 0.05). Bone turnover markers, indicative of bone accretion, were increased pre-to-post intervention in the M5 group only (P1NP; p = 0.036, P1NP/CTX ratio; p = 0.088). The overall anabolic response, as indicated by ranking low-to-high responders for Δ% LM (p = 0.0079), strength (p = 0.097), and performance (p = 0.19), was therefore significantly higher in the M5 vs. PLA group (p = 0.013).

CONCLUSIONS

Our findings confirm that obesity/MetS is a key driver of anabolic resistance in old age and that a high-quality, whey/casein-based MIS is more effective than a collagen-based alternative for maintaining musculoskeletal health in individuals at risk for sarcopenic obesity, even when total daily protein intake exceeds current treatment guidelines.

Comparison of surgical efficacy between direct anterior approach and posterolateral approach in the treatment of sarcopenia with femoral neck fractures

BACKGROUND

Femoral neck fracture (FNF) is a prevalent injury among the elderly, associated with significant morbidity and mortality. Total joint arthroplasty (TJA) has markedly enhanced the quality of life for many patients; however, the benefits of the direct anterior approach (DAA), which has gained popularity in recent years, remain a subject of debate. Sarcopenia frequently occurs in patients with FNF and is linked to adverse surgical outcomes. This study aims to compare the effects of the DAA and the posterolateral approach (PLA) on the efficacy of TJA surgery in patients with FNF who also present with sarcopenia.

METHODS

This study retrospectively analyzed the clinical data of patients with FNF who underwent total hip arthroplasty (THA) using either DAA or PLA from December 2019 to December 2022. A total of 141 individuals were included, comprising 52 in the DAA group and 89 in the PLA group. The cross-sectional area (cm²) of the musculature at the pedicle level of the 12th thoracic vertebra (T12) was measured using chest computed tomography (CT). The skeletal muscle index (SMI) was calculated by dividing the cross-sectional area of the muscle at the T12 pedicle level by the square of the individual's height. Sarcopenia was diagnosed when both grip strength and SMI values fell below the diagnostic cutoff. The study compared various factors, including age, gender, SMI, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, operation time, incision length, blood loss, blood transfusion, hemoglobin drop, albumin drop, postoperative time to ambulation, length of hospitalization, visual analogue scale (VAS) score, Harris score at one and six months post-surgery, complications, revision rate, one-year survival rate following surgery, and patient satisfaction.

RESULTS

There were no statistically significant differences between the two groups regarding gender, age, SMI, BMI, ASA, operation time, blood transfusion, VAS score six months post-surgery, revision rate, satisfaction, and survival rate (P > 0.05). The incision length, blood loss, hemoglobin drop, albumin drop, hospitalization duration, VAS score, and complication rate one month after the operation in the DAA group were all significantly lower than those in the PLA group (P < 0.001). Additionally, the Harris scores at one month and six days post-operation were superior in the DAA group compared to the PLA group (P < 0.001). Furthermore, the incidence of complications in the DAA group was lower than that in the PLA group (P = 0.041). Univariate and multivariate Cox regression analyses indicated that age was an independent risk factor for patients' mortality risk (95% CI: 1.064-1.479, P = 0.007).

CONCLUSION

DAA results in reduced surgical trauma, alleviates postoperative pain, decreases the incidence of complications, enhances the recovery of patients' mobility functions, shortens hospital stays, and is particularly suitable for FNF patients with sarcopenia.

Handgrip strength and body mass index exhibit good predictive value for sarcopenia in patients on peritoneal dialysis

Aim

The diagnosis of sarcopenia in patients on peritoneal dialysis (PD) in clinics is limited owing to its relatively complicated process and the need for expensive assessment equipment. This study aimed to develop and validate sex-specific nomogram models based on body mass index (BMI), handgrip strength, and other routine follow-up examination indicators to predict sarcopenia in patients on PD.

Methods

From March 2023 to February 2024, 699 eligible patients were recruited from the PD centers of two tertiary hospitals in southeastern China. Routine follow-up examination indicators such as age, BMI, biochemical indicators, dialysis adequacy, handgrip strength, and five-repetition sit-to-stand test, were used as potential predictive variables. Multivariate logistic regression analyses were used to separately determine the predictive factors for men and women. Nomogram models were constructed based on the results of the multivariate analyses, which were internally validated using a bootstrap re-sampling method (n = 2000). Predictive performance was validated using a receiver operating characteristic (ROC) curve.

Results

The prevalence of sarcopenia in Chinese patients on PD was 13.92%. The nomogram models based on multivariate analyses revealed both handgrip strength and BMI as independent predictors of sarcopenia in men and women on PD. The bootstrap-corrected area under the ROC curves of the models was 0.924 (95% CI: 0.888-0.959) and 0.936 (95% CI, 0.906-0.966) for men and women, respectively. The calibration curves of both models demonstrated high consistency between the observed and anticipated values.

Conclusion

The two nomogram models based on BMI and handgrip strength demonstrated good predictive ability for sarcopenia in male and female patients on PD. Subsequently, these may be used as convenient and inexpensive methods for the early detection and timely management of sarcopenia in patients on PD.

Diagnostic Power of Serum Creatinine/Cystatin C Ratio for Identifying Low MRI-Muscle Volume and Low Grip Strength: Data From 9 731 to 149 707 UK Biobank Older Adults

BACKGROUND

Biomarkers for sarcopenia are lacking. We examined the diagnostic power of serum creatinine to cystatin C ratio for identifying low magnetic resonance imaging-muscle volume and low grip strength in a large observational study of UK Biobank older adults.

METHODS

Serum creatinine and cystatin C were measured via immunoassays (Beckman Coulter AU5800 and Siemens Advia 1800, respectively) and grip strength by hydraulic hand dynamometer at baseline visit (2008-2010). magnetic resonance imaging-thigh fat-free muscle volume and DXA-derived appendicular lean mass were measured at imaging visit (2014-2018). Extreme outliers were removed, and covariates (demographic, lifestyle, and clinical factors, as well as time elapsed between baseline-imaging visit) were adjusted for in statistical models.

RESULTS

12 873 older adults (mean age: 63.5 ± 2.7 years, 44.2% women) were included for fat-free muscle volume and appendicular lean mass/body mass index; 149 707 older adults (mean age: 64.0 ± 2.9 years, 50.5% women) for grip strength. Despite significant associations (p < .05), in fully adjusted models, creatinine to cystatin C showed poor to acceptable diagnostic power for identifying low fat-free muscle volume when using cutpoints of 20th percentile (area under the curve: 0.577 men; 0.622 women) and T scores of -2 (area under the curve: 0.596 men; 0.659 women) and -2.5 (area under the curve: 0.609 men; 0.722 women). In fully adjusted model, creatinine to cystatin C showed poor diagnostic power (area under the curves: <0.70) for identifying low appendicular lean mass/body mass index or low grip strength, irrespective of the cutpoint used.

CONCLUSIONS

Creatinine to cystatin C may not be a suitable biomarker for identifying low muscle volume or low strength in older adults. This finding, drawn from a large sample size and the use of advanced medical imaging, marks an important contribution to the sarcopenia field.

Effects of BMI and grip strength on older adults' falls-A longitudinal study based on CHARLS

Background

Body Mass Index (BMI) and grip strength are potentially important risk factors for falls among the older adults. Currently, there is no consensus on the combined effects of grip strength and BMI on falls in the older adults, particularly among the Chinese older adults.

Objective

To investigate the incidence of falls among older adults in China and explore the association between BMI and grip strength and the risk of falls in older adults.

Methods

Data of participants over 60 in China Health and Retirement Longitudinal Study in 2011 and 2013 were collected. Sociodemographic variables, lifestyle, chronic disease status, history of falls and depression and cognitive status were obtained through the 2011 baseline questionnaire. Height, weight and grip strength were collected from a unified physical examination in 2011. Falls during the follow-up period were obtained through the follow-up questionnaire in 2013. Logistic regression was used to explore the association between BMI and grip strength and the risk of falls.

Results

Three thousand six hundred and eighty-five participants over 60 (67.14 ± 6.08) were included, with a fall incidence rate of 17.37%. The fall incidence rate in females (21.15%) was higher than that in male (13.46%). After adjusting covariates, high grip strength was associated with lower falls risks in general population (OR = 0.76; 95 CI: 0.630-0.923) and males (OR = 0.68; 95 CI: 0.503-0.919). Underweight was associated with lower falls risks in general population (OR = 0.77; 95 CI: 0.595-0.981) and females (OR = 0.69; 95 CI: 0.486-0.962) compared to the normal BMI group. Compared with the low grip strength group, females with high grip strength (OR = 0.54; 95 CI: 0.29-0.98) had a lower risk of falls in the underweight BMI group and males with high grip strength (OR = 0.63; 95 CI: 0.43-0.92) had lower risk of falls in the normal BMI group.

Conclusions

High grip strength and underweight BMI are independently correlated with a lower fall risk, which varies between males and females.

The potential of body mass index-adjusted calf circumference as a proxy for low muscle mass in the global leadership initiative on malnutrition criteria

BACKGROUND & AIMS

Reduced muscle mass is one of the diagnostic components for Global Leadership Initiative on Malnutrition (GLIM), with various assessment methods proposed. Calf circumference (CC), a representative anthropometric marker of skeletal muscle mass, is now recommended to adjustment based on body mass index (BMI). This study aimed to evaluate the validity and efficacy of BMI-adjusted CC in very older adults, compared with other methods of assessing muscle mass.

METHODS

This prospective cohort study included 284 patients aged 65 years and older who were admitted to the Department of Geriatric Medicine at the National Center for Geriatrics and Gerontology Hospital. Health indicators, including nutritional status, were assessed upon admission. Three months after discharge, a telephone survey was conducted to assess patients' living conditions and survival status. Skeletal muscle mass was estimated using a dual-energy X-ray absorptiometry (DXA); moreover, anthropometric measurements (unadjusted and BMI-adjusted CC) were used as markers of muscle mass. Logistic regression analysis was performed to examine the association between mortality and GLIM-based malnutrition, using each muscle mass assessment method.

RESULTS

The mean age of the patients was 86.2 ± 6.2 years, and 60.9 % were women. The prevalence of GLIM-based malnutrition ranged from 55.3 % to 58.8 % across the three methods used to assess reduced muscle mass. Three months after discharge, 244 patients were followed up, of whom 29 (11.9 %) died. Multivariate logistic regression analysis, adjusted for age, sex, and comorbidities, showed that all methods significantly predicted 3-month mortality, with odds ratios of 5.67, 5.44, and 4.90 for unadjusted CC, BMI-adjusted CC, and appendicular skeletal muscle mass index using DXA, respectively. The prevalence and survival-predictive ability were similar across all methods.

CONCLUSION

GLIM-based malnutrition, diagnosed using different methods for assessing muscle mass, similarly predicted 3-month mortality in patients admitted to an acute geriatric ward. These results suggest that BMI-adjusted CC are sufficient alternatives when technical measurements such as DXA are not feasible.

Sarcopenia: recent advances for detection, progression, and metabolic alterations along with therapeutic targets

Sarcopenia, a disorder marked by muscle loss and dysfunction, is a global health concern, particularly in aging populations. Sarcopenia is intricately related to various health conditions, including obesity, dysphagia, and frailty, which underscores the complexity. Despite recent advances in metabolomics and other omics data for early detection and treatment, the precise characterization and diagnosis of sarcopenia remains challenging. In the present review we provide an overview of the complex metabolic mechanisms that underlie sarcopenia, with particular emphasis on protein, lipid, carbohydrate, and bone metabolism. The review highlights the importance of leucine and other amino acids in promoting muscle protein synthesis and clarifies the critical role played by amino acid metabolism in preserving muscular health. In addition, the review provides insights regarding lipid metabolism on sarcopenia, with an emphasis on the effects of inflammation and insulin resistance. The development of sarcopenia is largely influenced by insulin resistance, especially with regard to glucose metabolism. Overall, the review emphasizes the complex relationship between bone and muscle health by highlighting the interaction between sarcopenia and bone metabolism. Furthermore, the review outlines various therapeutic approaches and potential biomarkers for diagnosing sarcopenia. These include pharmacological strategies such as hormone replacement therapy and anabolic steroids as well as lifestyle modifications such as exercise, nutrition, and dietary changes.

Automated extraction of body composition metrics from abdominal CT or MR imaging: A scoping review

PURPOSE

To review methodological approaches for automated segmentation of subcutaneous adipose tissue, visceral adipose tissue, and skeletal muscle from abdominal cross-sectional imaging for body composition analysis.

METHOD

Four databases were searched for publications describing automated segmentation of subcutaneous adipose tissue, visceral adipose tissue, and/or skeletal muscle from abdominal CT or MR imaging between 2019 and 2023. Included reports were evaluated to assess how imaging modality, cohort size, vertebral level, model dimensionality, and use of a volume or single slice affected segmentation accuracy and/or clinical utility. Exclusion criteria included reports not in English language, manual or semi-automated segmentation methods, reports prior to 2019 or solely of paediatric patients, and those not describing the use of abdominal CT or MR.

RESULTS

After exclusions, 172 reports were included in the review. CT imaging was utilised approximately four times as often as MRI, and segmentation accuracy did not significantly differ between the two modalities. Cohort size had no significant effect on segmentation accuracy. There was little evidence to refute the current practice of extracting body composition metrics from the third lumbar vertebral level. There was no clear benefit of using a 3D model to perform segmentation over a 2D approach.

CONCLUSION

Automated segmentation of intra-abdominal soft tissues for body composition analysis is an intense area of research activity. Segmentation accuracy is not affected by cross-sectional imaging modality. Extracting metrics from a single slice at the third lumbar vertebral level is a common approach, however, extracting metrics from a volumetric slab surrounding this level may increase the resilience of the technique, which is important for clinical translation. A paucity of publicly available datasets led to most reports using different data sources, preventing direct comparison of segmentation techniques. Future efforts should prioritise creating a standardised dataset to facilitate benchmarking of different algorithms and subsequent clinical adoption.

The impact of weight loss on fat-free mass, muscle, bone and hematopoiesis health: Implications for emerging pharmacotherapies aiming at fat reduction and lean mass preservation

Similar to bariatric surgery, incretin receptor agonists have revolutionized the treatment of obesity, achieving up to 15-25 % weight loss in many patients, i.e., at a rate approaching that achieved with bariatric surgery. However, over 25 % of total weight lost from both surgery and pharmacotherapy typically comes from fat-free mass, including skeletal muscle mass, which is often overlooked and can impair metabolic health and increase the risk of subsequent sarcopenic obesity. Loss of muscle and bone as well as anemia can compromise physical function, metabolic rate, and overall health, especially in older adults. The myostatin-activin-follistatin-inhibin system, originally implicated in reproductive function and subsequently muscle regulation, appears to be crucial for muscle and bone maintenance during weight loss. Activins and myostatin promote muscle degradation, while follistatins inhibit their activity in states of negative energy balance, thereby preserving lean mass. Novel compounds in the pipeline, such as Bimagrumab, Trevogrumab, and Garetosmab-which inhibit activin and myostatin signaling-have demonstrated promise in preventing muscle loss while promoting fat loss. Either alone or combined with incretin receptor agonists, these medications may enhance fat loss while preserving or even increasing muscle and bone mass, offering a potential solution for improving body composition and metabolic health during significant weight loss. Since this dual therapeutic approach could help address the challenges of muscle and bone loss during weight loss, well-designed studies are needed to optimize these strategies and assess long-term benefits. For the time being, considerations like advanced age and prefrailty may affect the choice of suitable candidates in clinical practice for current and emerging anti-obesity medications due to the associated risk of sarcopenia.

Resistance training, skeletal muscle hypertrophy, and glucose homeostasis: how related are they? A Systematic review and Meta-analysis

Resistance training (RT) promotes skeletal muscle (Skm) hypertrophy, increases muscular strength, and improves metabolic health. Whether changes in fat-free mass (FFM; a surrogate marker of muscle hypertrophy) moderate RT-induced improvements in glucose homeostasis has not been determined, despite extensive research on the benefits of RT for health and performance. The aim of this meta-analysis is to examine whether RT-induced Skm hypertrophy drives improvements in glucose metabolism and to explore confounders, such as biological sex and training parameters. Random-effects meta-analyses were performed using variance random effects. Meta-regressions were performed for confounding factors depending on the heterogeneity (I2). Analyses from 33 intervention studies revealed significant within-study increases in FFM with a moderate effect size (within-studies: (effect size; ES = 0.24 [0.10; 0.39]; p = 0.002; I2 = 56%) and a tendency for significance when compared with control groups (ES = 0.42 [-0.04-0.88]; p = 0.07). Within-study significant increases in glucose tolerance (2 h glucose: ES = -0.3 [-0.50; -0.11]; p < 0.01; I2 = 43%; glucose area under the curve (AUC): -0.40 [-0.66; -0.13] I2 = 76.1%; p < 0.01) and insulin sensitivity (ES = 0.38 [0.13; 0.62]; I2 = 53.0%; p < 0.01) were also apparent with RT. When compared to control groups, there was no significant difference in 2 h glucose, nor in glucose AUC from baseline in RT intervention groups. Meta-regression analyses failed to consistently reveal increases in FFM as a moderator of glucose homeostasis. Other mixed-effect models were also unsuccessful to unveil biological sex or training parameters as moderators of FFM increases and glucose homeostasis changes. Although Skm hypertrophy and improvements in glycemic control occur concurrently during RT, changes in these variables were not always related. Well-controlled trials including detailed description of training parameters are needed to inform RT guidelines for improving metabolic health. Registration and protocol number (Prospero): CRD42023397362.

Underpowered studies in muscle metabolism research: Determinants and considerations

Biomedical research frequently employs null hypothesis testing to determine whether an observed difference in a sample is likely to exist in the broader population. Null hypothesis testing generally assumes that differences between groups or interventions are non-existent, unless proven otherwise. Because biomedical studies with human subjects are often limited by financial and logistical resources, they tend to have low statistical power, i.e. a low probability of statistically confirming a true difference. As a result, small but potentially clinically important differences may be overseen or ignored simply due to the absence of a statistically significant difference. This absence is often misinterpreted as 'equivalence' of treatments. In this educational paper, we will use practical examples related to the effects of exercise and nutrition on muscle protein metabolism to illustrate the most important determinants of statistical power, as well as their implications for both investigators and readers of scientific articles. Changes in muscle mass occur at a relatively slow rate, making it practically challenging to detect differences between treatment groups in a long-term setting. One way to make it 'easier' to differentiate between groups and hence increase statistical power is to have a sufficiently long study duration to allow treatment effects to become apparent. This is especially relevant when comparing treatments with relatively small expected differences such as the effect of modest changes in daily protein intake. Secondly, one could try to minimize the variance and response heterogeneity within groups, for example by using strict inclusion criteria and standardization protocols (e.g., meal provision), by using cross-over designs, or even within-subject designs where two interventions are compared simultaneously (e.g., studying an exercised limb vs a contralateral control limb) although this might limit the generalizability of the findings (e.g. such single-limb exercise training is not common in practice). In terms of data interpretation, investigators should obviously refrain from drawing strong conclusions from underpowered studies. Yet, such studies still provide valuable data for meta-analyses. Finally, because muscle protein synthesis rates are highly responsive to anabolic stimuli, acute metabolic studies are more sensitive to detect potentially clinically relevant differences in the anabolic response between treatments. Apart from further elaborating on these topics, this educational article encourages readers to more critically question null findings and scientists to more clearly discuss limitations that may have compromised statistical power.

Effects and mechanisms of APP and its cleavage product Aβ in the comorbidity of sarcopenia and Alzheimer's disease

Sarcopenia and AD are both classic degenerative diseases, and there is growing epidemiological evidence of their comorbidity with aging; however, the mechanisms underlying the biology of their commonality have not yet been thoroughly investigated. APP is a membrane protein that is expressed in tissues and is expressed not only in the nervous system but also in the NMJ and muscle. Deposition of its proteolytic cleavage product, Aβ, has been described as a central component of AD pathogenesis. Recent studies have shown that excessive accumulation and aberrant expression of APP in muscle lead to pathological muscle lesions, but the pathogenic mechanism by which APP and its proteolytic cleavage products act in skeletal muscle is less well understood. By summarizing and analyzing the literature concerning the role, pathogenicity and pathological mechanisms of APP and its cleavage products in the nervous system and muscles, we aimed to explore the intrinsic pathological mechanisms of myocerebral comorbidities and to provide new perspectives and theoretical foundations for the prevention and treatment of AD and sarcopenia comorbidities.

Dysphagia and Body Composition in Cornelia de Lange Syndrome

BACKGROUND/OBJECTIVES

Limited research had investigated nutritional status in patients with Cornelia de Lange Syndrome (CdLS) (OMIM 122470, 300590, 300882, 610759, 620568 and 614701). Body composition assessed via bioelectric impedance (BIA) is a particularly under-explored issue. In this cross-sectional study, we hypothesize that body composition imbalance is frequent in CdLS and may be associated with dysphagia. We aimed to determine dysphagia prevalence in CdLS. Dysphagia may be a sign or a complication of GERD (gastroesophageal reflux disease), which is the most frequent gastroenterological disorder in CdLS patients; Methods: Fourteen Polish patients with a clinical or genetic diagnosis of CdLS were included in the study. We performed body composition analysis via bioelectric impedance taking into account the phase angle (PhA) and Body Cell Mass (BCM) in patients who cooperated and were able to sit still. The patients' caregivers completed the pediatric version of the Eating Assessment Tool (PEDI-EAT-10). Based on the questionnaire scoring, we divided the patients into dysphagic and non-dysphagic groups. Body compartments of those two groups were compared. Statistical correlations between PhA and the PEDI-EAT-10 score were calculated; Results: Eleven of the fourteen CdLS patients had abnormalities in the BIA analysis in terms of fat mass (FM), fat free mass (FFM) and skeletal muscle mass (SMM). Six patients had excessive FM and four patients were deficient in FM. Two had deficiency in FFM and two had excessive FFM. We noted prevalence of dysphagia at 28.57%, with four patients having an PEDI-EAT-10 score higher or equal to 3, categorized as dysphagic. The dysphagic and non-dysphagic groups were not significantly different in terms of the proportion of patients with FM, FFM, SMM and BCM in the small cohort presented here. A statistically significant inverse correlation was found between the PhA and PEDI-EAT-10 score (rho = -0.72; p = 0.003); Conclusions: CdLS patients require investigation for dysphagia and nutritional status imbalance, as they are both frequent in this syndrome. The most prevalent are abnormalities in FM, both excess and deficit. PhA deviations observed in the bioimpedance study deepen with the severity of dysphagia. These findings require further investigation in a larger cohort.

Advances in sarcopenia and urologic disorders

Sarcopenia is a loss of muscle strength, muscle mass, and function that can increase a patient's risk of injury, illness, and can even severely impair quality of life and increase a patient's risk of death. A growing body of research suggests that sarcopenia and urinary tract disorders are closely related. In this review, we aimed to emphasize the definition of skeletal sarcopenia, summarize the methods used to diagnose skeletal sarcopenia, discuss the advances in the study of sarcopenia in benign diseases of the urinary system, discuss the advances in the study of sarcopenia in malignant diseases of the urinary system. Sarcopenia and urologic diseases interact with each other; urologic diseases cause sarcopenia, and sarcopenia aggravates the condition of the original disease, thus falling into a vicious circle. This review provides a comprehensive understanding of sarcopenia in urologic diseases, which is very important for the management and prognosis of urologic diseases.

Review of Exercise Interventions to Improve Clinical Outcomes in Nondialysis CKD

Exercise interventions in chronic kidney disease (CKD) have received growing interest, with over 30 meta-analyses published in the past 5 years. The potential benefits of exercise training in CKD range from slowing disease progression to improving comorbidities and quality of life. Nevertheless, there is a lack of large, randomized control trials in diverse populations, particularly regarding exercise in nondialysis-dependent CKD (NDD). When exercise interventions are implemented, they often lack fundamental features of exercise training such as progressive overload, personalization, and specificity. Furthermore, the physiology of exercise and CKD-specific barriers appear poorly understood. This review explores the potential benefits of exercise training in NDD, draws lessons from previous interventions and other fields, and provides several basic tools that may help improve interventions in research and practice.

Effects of Creatine Monohydrate Supplementation on Muscle, Bone and Brain- Hope or Hype for Older Adults?

PURPOSE OF REVIEW

Sarcopenia, generally characterized by the age-related reduction in muscle strength, lean/muscle mass and functional ability, is also associated with reduced bone mass and strength and impaired brain health and function. One potential intervention which has received much 'hype' over the past few decades to countermeasure these negative consequences of biological aging is creatine monohydrate supplementation.

RECENT FINDINGS

From a skeletal muscle perspective, the combination of creatine monohydrate supplementation and resistance training provides 'hope' for older adults as it improves measures of lean mass, regional (limb) muscle thickness, upper- and lower-body muscle strength and functional ability. Further, there is some evidence that creatine (supplementation or habitual diet) provides a ray of 'hope' for improving some aspects of cognitive function. The majority of research suggests that creatine is more 'hype' than 'hope' for improving measures of bone mass in older adults. Creatine monohydrate supplementation provides some anti-sarcopenic benefits for older adults.

Sarcopenia as a Risk Factor for Mortality in NAFLD: How Should We Diagnose It?

OBJECTIVES

Sarcopenia increases the risk of nonalcoholic steatohepatitis (NASH) and cirrhosis in patients with nonalcoholic fatty liver disease (NAFLD). Subsequently, poorly managed NAFLD can result in adverse health outcomes. Lifestyle interventions are effective for both NAFLD and sarcopenia; however, diagnosis of sarcopenia in this population is not well defined. This review aimed to examine current methods to diagnose sarcopenia in NAFLD patients.

METHODS

MEDLINE, EMBASE, and CINAHL databases were searched for articles published until July 2023 using the terms "Non-alcoholic fatty liver disease," "NAFLD," "fatty liver," "sarcopenia," and "myoatrophy." Studies were excluded if they included pediatric populations, did not diagnose both sarcopenia and NAFLD, or included patients with alternate causes of liver disease.

RESULTS

Twenty studies, predominantly from Asian countries (14 [70.0%]), involving 68 848 participants (45.5% females) were included. In 15 studies, most participants had a BMI > 25 kg/m2. Heterogeneity in the tools used to diagnose NAFLD was identified, with abdominal ultrasound being the most commonly used. European, Asian, and Australasian Sarcopenia Working Groups had differing diagnostic definitions of sarcopenia. Of the three potential diagnostic elements of sarcopenia (muscle mass, strength, function), all studies measured muscle mass, commonly through bioelectrical impedance analysis (12 [60.0%]). Seven studies (35.0%) measured muscle strength, with the majority (n = 6) utilizing hand grip strength. Four (20.0%) measured muscle function, through gait speed or a timed up-and-go test.

CONCLUSIONS

The lack of standardization in sarcopenia diagnosis for NAFLD patients is concerning. A consistent definition is necessary to prevent this comorbidity from being overlooked, improve care, and outcomes.