INTRODUCTION: The diagnosis of sarcopenia relies on key indicators such as handgrip strength, walking speed and muscle mass. Developing a composite index that integrates these measures could enhance clinical evaluation in older adults. This study aimed to standardise and combine these metrics to establish a z score for the sarcopenia composite index (ZoSCI) tailored for the ageing population. Additionally, we explore the risk factors associated with ZoSCI to provide insights into early prevention and intervention strategies. METHOD: This retrospective study analysed data between January 2017 and December 2021 from an elderly health programme in Taiwan, applying the Asian Working Group for Sarcopenia criteria to assess sarcopenia. ZoSCI was developed by standardising handgrip strength, walking speed and muscle mass into z scores and integrating them into a composite index. Receiver operating characteristic (ROC) curve analysis was used to determine optimal cut-off values, and multiple regression analysis identified factors influencing ZoSCI. RESULTS: Among the 5047 participants, the prevalence of sarcopenia was 3.7%, lower than the reported global prevalence of 3.9-15.4%. ROC curve analysis established optimal cut-off points for distinguishing sarcopenia in ZoSCI: -1.85 (sensitivity 0.91, specificity 0.88) for males and -1.97 (sensitivity 0.93, specificity 0.88) for females. Factors associated with lower ZoSCI included advanced age, lower education levels, reduced exercise frequency, lower body mass index and creatinine levels. CONCLUSION This study introduces ZoSCI, a new compo-site quantitative indicator for identifying sarcopenia in older adults. The findings highlight specific risk factors that can inform early intervention. Future studies should validate ZoSCI globally, with international collaborations to ensure broader applicability.
Humans ; Sarcopenia/physiopathology* ; Male ; Aged ; Female ; Retrospective Studies ; Hand Strength ; Taiwan/epidemiology* ; ROC Curve ; Aged, 80 and over ; Risk Factors ; Walking Speed ; Geriatric Assessment/methods* ; Prevalence ; Muscle, Skeletal ; Middle Aged

The increasing prevalence of aging has led to a rising incidence of comorbidity of sarcopenia and obesity, posing significant burdens on socioeconomic and public health. Current research has systematically explored the pathogenesis of each condition; however, the mechanisms underlying their comorbidity remain unclear. This study reviews the current literature on sarcopenia and obesity in the aging population, focusing on their shared biological mechanisms, which include loss of autophagy, abnormal macrophage function, mitochondrial dysfunction, and reduced sex hormone secretion. It also identifies metabolic mechanisms such as insulin resistance, vitamin D metabolism abnormalities, dysregulation of iron metabolism, decreased levels of nicotinamide adenine dinucleotide, and gut microbiota imbalances. Additionally, this study also explores the important role of genetic factors, such as alleles and microRNAs, in the co-occurrence of sarcopenia and obesity. A better understanding of these mechanisms is vital for developing clinical interventions and preventive strategies.
Humans ; Sarcopenia/physiopathology* ; Obesity/physiopathology* ; Aging/physiology* ; Autophagy/physiology* ; Insulin Resistance ; Comorbidity ; Vitamin D/metabolism* ; Gonadal Steroid Hormones/metabolism* ; Gastrointestinal Microbiome ; Mitochondria ; MicroRNAs

OBJECTIVE: To investigate the clinical characteristics of overlapping syndromes of low muscle mass in Chinese patients with rheumatoid arthritis (RA) and their impact on physical function. METHODS: Consecutive patients with RA were recruited from September 2019 to April 2024 at Department of Rheumatology and Immunology, Sun Yat-Sen Memorial Hospital. Clinical data including disease acti-vity, physical function and radiographic assessment were collected. All patients also finished measurement of body composition, grip strength, and gait speed, and overlapping syndromes of low muscle mass as well as malnutrition, sarcopenia, sarcopenic obesity, and cachexia were evaluated. The Stanford health assessment questionnaire- disability index (HAQ-DI) was used to evaluate physical function. Logistic regression was used to analyze the related factors of physical dysfunction. RESULTS: A total of 1 016 RA patients were recruited. Their mean age was (52.4±12.5) years, and 82.5% were female. There were 557 cases (54.8%) with overlapping syndromes of low muscle mass and all of them were malnutrition. On this basis, 326 cases (32.1%) exhibited sarcopenia, 124 (12.2%) sarcopenic obesity, and 33 (3.2%) cachexia. There were 584 (57.4%) of RA patients having physical dysfunction, with varying degrees of severity 421 (41.4%) mild, 124 (12.2%) moderate, and 39 (3.8%) severe. Compared with patients without overlapping syndromes of low muscle mass (n=459) or with malnutrition only (n=231), RA patients with both malnutrition and sarcopenia (n=326) had significantly higher core disease activity indicators and higher rate of physical dysfunction (69.6% vs. 42.0% vs. 56.6%). However, compared with patients without overlapping syndromes of low muscle mass, patients with malnutrition only had lower HAQ-DI score (median 0.0 vs. 0.1) and lower rate of physical dysfunction (42.0% vs. 56.6%). Multivariate Logistic regression analysis showed that simultaneously overlapping malnutrition and sarcopenia were associated factors of physical dysfunction (OR=2.021, 95%CI: 1.067-3.828), but malnutrition only was not. CONCLUSION Simultaneously overlapping malnutrition and sarcopenia can deteriorate disease activity and physical dysfunction in RA patients. The screening and evaluation of overlapping syndromes of low muscle mass, especially sarcopenia should be emphasized in patients with RA.
Humans ; Arthritis, Rheumatoid/physiopathology* ; Female ; Male ; Sarcopenia/complications* ; Middle Aged ; Cachexia/diagnosis* ; Malnutrition/etiology* ; Obesity/physiopathology* ; Body Composition ; Syndrome ; Hand Strength ; Adult ; Muscle, Skeletal/physiopathology* ; Surveys and Questionnaires

Sarcopenia is an age-related degenerative skeletal muscle disorder characterized by the loss of skeletal muscle mass and function during aging.Sarcopenia can impair the elderly's ability to perform daily activities and is associated with high risks of falls,fractures,and hospitalization.It seriously affects the quality of life of the elderly and becomes one of the major health problems in the aging society.Skeletal muscle stem cells,also known as muscle satellite cells,play a key role in supporting muscle regeneration and homeostasis maintenance.Studies have suggested that muscle satellite cell functions are tightly regulated by microenvironment signals in the skeletal muscle.Of note,skeletal muscle fibers,serving as an immediate niche of muscle satellite cells,regulate their activation,proliferation,and self-renewal.This article reviews the research progress in the regulatory roles of skeletal muscle stem cells and their microenvironment in sarcopenia during aging,providing theoretical support for potential treatment of sarcopenia via modifying skeletal muscle microenvironment and regulating muscle satellite cell functions.
Sarcopenia/physiopathology* ; Humans ; Satellite Cells, Skeletal Muscle/physiology* ; Muscle, Skeletal/physiopathology* ; Aging/physiology* ; Animals ; Stem Cells

The increase in the proportion of elderly people in the population is one of the most remarkable sociodemographic phenomena of the twenty-first century. The number of patients with diabetes is also increasing worldwide with this demographic change. Given these facts, consideration of the problems the general elderly population is facing in the management of diabetes is essential. In this review article, we focus on sarcopenia, which is the decrease in lower extremity muscle mass and muscle strength accompanying aging, describe the relationship between sarcopenia and diabetes, and highlight the specific factors through which diabetes contributes to loss of muscle strength. The quantitative methods for evaluating lower extremity muscle strength will also be described. These methods hold the key to assessing the effectiveness of exercise therapy and optimizing the assessment of the degree of autonomy in the activities of daily living. Exercise is one of the basic treatments for type 2 diabetes and may also prevent and improve sarcopenia. This review discusses the aspects common to the two health conditions and elucidates the effectiveness and necessity of exercise as a preventive measure against diabetes among the elderly.
Aged ; Aged, 80 and over ; Diabetes Mellitus, Type 2 ; physiopathology ; prevention & control ; Exercise Therapy ; Female ; Humans ; Leg ; physiopathology ; Male ; Muscle Strength ; physiology ; Muscle, Skeletal ; physiology ; Sarcopenia ; physiopathology ; prevention & control

The purpose of this study was to predict osteoporosis risk as decreasing muscle mass and to declare the cut-off value of low muscle mass in an elderly Korean population. This study was based on data from the 2008-2010 Korea National Health and Nutritional Examination Surveys (KNHANES). The subjects included 1,308 men and 1,171 women over 65 yr. Bone mineral density (BMD) and appendicular skeletal muscle (ASM) were measured by dual energy X-ray absorptiometry (DXA), and appendicular skeletal muscle was adjusted by height as a marker of sarcopenia. After confirming the correlation between low muscle mass and BMD, the best cut-off value of muscle mass to estimate osteoporosis was suggested through the receiver operating characteristic (ROC) curve. For both men and women, BMD correlated positively with low muscle mass when ASM/Ht2 was used as a marker for sarcopenia. The ROC curve showed that ASM/Ht2 was the best marker for osteoporosis at a cut-off value of 6.85 kg/m2 for men and 5.96 kg/m2 for women. When these cut-off values were used to determine sarcopenia, the risk of osteoporosis increased 4.14 times in men and 1.88 times in women. In particular, men (OR 2.12) with sarcopenia were more greatly affected than women (OR 1.15), even after adjusting for osteoporosis risk factors. In elderly Korean people, sarcopenia is positively correlated with BMD and there is a strong correlation between sarcopenia and osteoporosis with risk of bone fracture.
Absorptiometry, Photon ; Aged ; Aged, 80 and over ; Area Under Curve ; Asian Continental Ancestry Group ; Body Mass Index ; Bone Density ; Female ; Humans ; Male ; Muscle, Skeletal/*pathology/radiography ; Nutrition Surveys ; Odds Ratio ; Osteoporosis/*diagnosis/etiology ; ROC Curve ; Republic of Korea ; Risk Factors ; Sarcopenia/physiopathology