Background and Objectives: It is thought that muscle and bone interact only on a biomechanical level, however, some research is now emerging that links bone and muscle on a cellular level. The aim of this study was to explore associations between physical function, muscle mass and bone density in community-dwelling elderly men with sarcopenia. A secondary goal was to analyze if muscle morphology was associated with bone density and physical functioning. Materials and Methods: Body composition was measured by dual-energy X-ray absorptiometry (DXA). Bone density was evaluated according to WHO criteria. Sarcopenia was diagnosed according to European Working Group on Sarcopenia in Older People (EWGSOP) criteria: low muscle mass and low muscle strength or low physical performance. Microbiopsy of musculus vastus lateralis was performed with a disposable muscle microbiopsy system. The perimeter and cross-sectional area of muscle fibers were calculated using image analysis software in whole slide images; type of fibers and their distribution were evaluated as well. Results: A total of 151 men, 60 years or older were included in this study. Mean age of the subjects was 72.9 ± 8.02 years. Sarcopenia was diagnosed in 45 (29.8%) men. Multiple significant correlations were found between bone mineral density, lean mass, appendicular lean mass, arm and leg lean mass, gait speed, balance test and handgrip strength in sarcopenic men. Lean mass was associated with femoral neck BMD (bone mineral density; r = 0.418, p = 0.006) and handgrip strength (r = 0.553, p < 0.001). In the sarcopenia group, 25 muscle biopsies were examined. In 9 sarcopenic men with T-scores equal or below −2.5, the muscle fiber area had a significant correlation with the balance test (r = 0.73, p = 0.025). Conclusions: In men with sarcopenia, low lean muscle mass was associated with low femoral neck BMD and low muscle strength. In sarcopenic men with osteoporosis, low muscle fiber area was associated with low scores in a balance test.

Introduction: The influence of physical frailty and sarcopenia (PFS) on the well-being of older people and continuous pressure on the healthcare systems has prompted a research on the pathophysiology and molecular mechanisms of these conditions. Nonetheless some biomarkers have been suggested as potential markers for PFS none of them have been shown to highlight the complex nature of PFS, which reveals that there is a need for an understanding of the possible biomarker candidates. The aim of this study was to identify the current research hotspots, status, and trends in the field of biomarkers and molecular mechanisms for PFS.Methods: The bibliometric and scientometric analyses were performed using VOSviewer (version 1.6.18) and open source software platform Cytoscape v.3.9 (for visualizing and constructing a network of keywords). Data of publications (from 1997 to 2023) related to biomarkers and molecular mechanisms of PFS were obtained (in May 2023) from the database of Science Citation Index Expanded of Web of Science, Scopus, and PubMed. The keywords obtained from the Scopus database were used to perform a meaningful keyword analysis. A network of keyword relationships was build using Cytoscape.Results: In this study, we present biomarker keywords for PFS in relation to other keywords potentially designating processes and mechanisms and reveal the biomarker identities and current contexts in which these biomarker identities are discussed.Conclusions: Over recent years, scientific interest in the field of PFS has increased and focused on the inflammatory process and probably will be concentrated on myokines (such as cytokines and small proteins) that are synthetized and released by skeletal muscles in response to physical activity. Moreover, proteomic and genetic markers are deeply involved in PFS.

The development of frailty and sarcopenia is influenced by age-related physiological changes and gene-environment interactions, accelerating musculoskeletal decline and systemic dysfunction in older adults. Mendelian randomization (MR) use genetic variants as instrumental variables to assess causality. This study systematically reviewed two-sample MR studies investigating causal relationships of frailty and sarcopenia-related traits with various health outcomes. Following PRISMA guidelines, PubMed and Scopus were searched (last accessed June 27, 2025) using terms including "Mendelian randomization", "sarcopenia", "lean mass" or "fat free mass", "strength", "walking pace", "gait", and "frailty." Study quality was assessed via STROBE-MR checklist. Extracted data included exposure/outcome details, MR results (odds ratios or beta values with 95 % confidence intervals, p-value of the causal association), and instrumental variable sources. The final analysis included a total of 68 articles on sarcopenia-related traits and 96 on frailty. Gait speed causally affected 25 traits and was affected by 26 traits. Handgrip strength causally affected 20 traits and was affected by 83 traits. Lean mass related phenotypes causally affected 45 traits and were affected by 85 traits. Frailty had a causal effect on 191 traits and was affected by 75 traits. Causal links between 19 groups of disease traits and sarcopenia and frailty were confirmed in observational studies (OS) and MR studies. In the majority of studies, increased muscle strength, lean mass, a faster walking pace, and lower frailty served as protective factors against the risk of many diseases and were positively associated with cognitive function. In this systematic review, we identified robust evidence supporting causal associations of both frailty and sarcopenia with a range of health-related outcomes, including sociodemographic and lifestyle factors, respiratory and musculoskeletal disorders, autoimmune disorders, inflammatory bowel disease, changes in gut microbiota, and neurological and vascular conditions. This review was preregistered with PROSPERO (CRD420251110335).

Background and Objectives: Information on how psychomotor speed is associated with the risk of falling is scarce, even in older adults. Therefore, this study aimed to determine the relationship between falls and psychomotor speed in older adults with sarcopenia and frailty. Materials and Methods: A total of 204 subjects (aged 83 (77–87) years) participated in this study: 161 women (78.9%) and 43 men (21.1%). The history of falls was assessed by asking whether the subject had experienced a fall in the past 12 months. Psychomotor speed was evaluated by reaction time and frequency of movement. Sarcopenia was diagnosed based on the EWGSOP2 criteria. Frailty was confirmed if the participants met ≥3 criteria according to the Fried frailty criteria. The relationship between falls and psychomotor speed was measured using partial correlations. Binary logistic regression analysis was used to assess if psychomotor speed had an impact on falls. Results: Sarcopenia was confirmed in 93 (45.58%) and frailty in 91 (44.6%) subjects. Both sarcopenia and frailty were present in 62 (30.39%) participants. In the sarcopenia and frailty group, falls were related to simple reaction time (r = 0.444, p = 0.002), hand movement frequency in 10 s (r = −0.352, p = 0.014), and in 60 s (r = −0.312, p = 0.026). In women with sarcopenia and frailty, there were relationships between falls and simple reaction time (r = 0.68, p = 0.002), complex reaction time (r = 0.406, p = 0.004), hand movement frequency in 10 s (r = −0.614, p = 0.001), and in 60 s (r = −0.584, p = 0.001). In regression analysis, it was found that each millisecond increase in reaction time was associated with a 1.5% higher fall risk in the participants with sarcopenia (OR: 1.015 [1, 1.031], p = 0.048). Conclusions: This study demonstrates that slower psychomotor speed, particularly reaction time, is linked to a higher risk of falls in older adults with sarcopenia and frailty, especially in women.