Prevalence of non-alcoholic fatty liver disease across populations and comorbid conditions: An umbrella review of meta-analyses
Yue Feng, Peiye Wu, Rui Zhao, Xiaoding Shen, Xixuan Peng, Leyao Qiu, Can Zhu, Zhuolin Jiang, Huatian Gan, Qianyi WanBackground
Non-alcoholic fatty liver disease (NAFLD) affects approximately one-third of the global population, but reported prevalence varies across populations and comorbid conditions.
Objectives
To characterize the global prevalence of NAFLD across diverse populations and comorbid conditions.
Design
Umbrella review of meta-analyses.
Data sources and methods
This review searched PubMed, Web of Science, Embase, and Cochrane Library for meta-analyses. Methodological and evidence quality were evaluated using AMSTAR 2 and GRADE.
Results
We included 22 meta-analyses reporting 67 outcomes. NAFLD prevalence was numerically high in adults with obesity (75.27%), adults with overweight (69.99%), and patients with type 2 diabetes (65.04%). The lean-population estimate was 1.94% and was based on metabolic dysfunction-associated fatty liver disease (MAFLD) criteria. Geographically, South America had the numerically highest general-population estimate (34.00%). Additionally, non-alcoholic steatohepatitis (NASH) prevalence in adults with obesity was 33.67%, and significant liver fibrosis (F2–F4) prevalence in people with type 2 diabetes and NAFLD was 35.54%. Evidence certainty was predominantly low or very low due to bias.
Conclusion
NAFLD prevalence exhibits marked variability, necessitating targeted weight-management interventions in high-risk groups. However, most prevalence estimates were supported by low or very low certainty evidence and should therefore be interpreted cautiously. Given the substantial heterogeneity in existing literature, future studies must prioritize methodological refinement and harmonized diagnostic approaches, particularly as the field transitions toward metabolic dysfunction-associated steatotic liver disease (MASLD) criteria.