Sarcopenia as a risk factor for nonalcoholic fatty liver disease and liver fibrosis: an updated systematic review and meta-analysis

Background Sarcopenia, an age-related skeletal muscle disorder with metabolic dysregulation, has been linked to various chronic diseases. Emerging evidence suggests a bidirectional relationship with nonalcoholic fatty liver disease (NAFLD), though the epidemiological and mechanistic links remain unclear. This study aimed to assess the prevalence of sarcopenia in NAFLD populations and its association with NAFLD and liver fibrosis. Methods PubMed, EMBASE, MEDLINE, Cochrane Library, and Web of Science databases were searched for eligible studies published until August 6, 2025. Two validated tools assessed the study quality and risk of bias. Statistical analyses were conducted using STATA 17.0. This study has been registered on PROSPERO (CRD420251021280). Results From 4,938 screened records, 41 studies ( n = 185,575) were retrieved. The prevalence of sarcopenia in patients with NAFLD varied substantially (0.8 to 80.9%), with a pooled estimate significantly higher than that in non-NAFLD controls 23% (95% CI: 20 to 26%) vs. 15% (95% CI: 13 to 17%). Meta-analysis revealed that sarcopenia was associated with a 1.58-fold increased risk of NAFLD (95% CI: 1.37 to 1.82) and a 2.03-fold risk of concomitant liver fibrosis (95% CI: 1.54 to 2.68). Subgroup analyses showed that the association was consistent across different muscle mass assessment methods, but varied by NAFLD diagnostic modality. CT-based NAFLD diagnosis yielded the highest aORs, while transient elastography showed a non-significant association. Conclusion This study confirms a high prevalence of sarcopenia in NAFLD populations and a significant association with NAFLD and liver fibrosis, supporting its role as a modifiable risk factor. However, heterogeneity due to diagnostic variability remains a limitation. Standardized criteria and longitudinal studies are needed to establish causality. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/ , PROSPERO: CRD420251021280.