Socioeconomic Factors and Their Role in Metabolic Dysfunction-Associated Steatotic Liver Disease: A Comprehensive Review.

Metabolic dysfunction-associated steatotic liver disease (MASLD), a major public health concern, is influenced by an interplay of genetic, environmental, and lifestyle factors, with socioeconomic factors functioning as important upstream determinants whose roles remain not yet fully understood. This review synthesizes current evidence on how different indicators of socioeconomic status as well as related social determinants of health-income, poverty, food insecurity, health insurance, education, migration, and composite indices-relate to MASLD prevalence, severity, and outcomes across different world regions. Several studies associate these socioeconomic factors with an increased risk of MASLD, illustrating the disease's link with socioeconomic disadvantages. However, socioeconomic factors often lose or attenuate their independent association with MASLD once key downstream determinants-such as diet quality, physical inactivity, and metabolic comorbidities-are considered, supporting a model in which socioeconomic factors mainly shape exposure to metabolic and behavioural risk factors rather than exerting a direct causal effect. Among the factors examined, education and food insecurity demonstrate the most consistent independent associations with MASLD. Notably, the direction of socioeconomic gradients appears to differ by regional income level, with lower SES associated with higher MASLD burden in high-income countries but an inverse pattern in several middle-income settings. Evidence remains largely limited to the United States, Europe, and a small number of Asian cohorts, underscoring the need for more geographically diverse research. This review highlights the association of different socioeconomic factors with MASLD, while also revealing the need for more detailed studies which systematically disentangle individual and area-level social determinants of health, model mediating pathways and incorporate underrepresented regions and paediatric populations. A deeper understanding of how socioeconomic factors and downstream mediators jointly drive MASLD could inform targeted clinical strategies and multi-level policies aimed at mitigating the social gradient in MASLD.