Global prevalence and risk factors of probable sarcopenia in older adults: a protocol for systematic review and meta-analysis

INTRODUCTION: With the acceleration of the global ageing trend, sarcopenia has become a major public health problem. Probable sarcopenia, characterised primarily by decreased muscle strength, represents an early, potentially reversible stage. However, epidemiological evidence on the prevalence and risk factors of probable sarcopenia in older populations remains limited, scattered, and methodologically inconsistent. Therefore, systematic reviews and meta-analyses are needed to synthesise current data, quantify global and regional prevalence, identify associated risk factors, and explore sources of heterogeneity. METHODS AND ANALYSIS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols 2020 and Joanna Briggs Institute (JBI) methodologies, this review will include observational studies that define probable sarcopenia according to recognised consensus criteria (European Working Group on Sarcopenia in Older People 2 and Asian Working Group for Sarcopenia 2). Comprehensive searches of eleven English and Chinese databases (Web of Science, PubMed, MEDLINE, Embase, Scopus, CENTRAL, CINAHL, CBM, CNKI, WANFANG, and VIP) will be conducted from inception to January 2026. Two reviewers will independently screen, extract, and appraise studies using JBI tools. Random-effects meta-analyses will be used to estimate global and regional prevalence and to synthesise the available evidence on associated risk factors. Pre-specified subgroup and meta-regression analyses will be undertaken to explore potential sources of heterogeneity across diagnostic criteria, geographical regions, and population characteristics. ETHICS AND DISSEMINATION: Ethical approval was not required for this protocol. The results of the final review will be disseminated in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD420251153142.