Incidence of metabolic dysfunction-associated steatotic liver disease and advanced fibrosis and impact of overweight/obesity in elderly population: a nationwide cohort study.

Background and aim: The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing worldwide, coinciding with aging population. However, limited studies have evaluated its incidence and progression to advanced fibrosis in the elderly population. Therefore, our study aimed to investigate the incidence of MASLD and advanced fibrosis in this age group.

Methods: We included 878 686 individuals aged ≥60 years from the Korea National Health Insurance Service-Senior cohort. After excluding participants with preexisting MASLD, 329 388 individuals were finally analyzed. Participants were categorized into four groups based on the presence of overweight/obesity and additional risk factors (aRF) included in the cardiometabolic diagnostic criteria of MASLD.

Results: The overall incidence of MASLD was 1.94 per 100 person-years, and the incidence of advanced fibrosis in MASLD patients was 1.78 per 100 person-years. MASLD development was significantly higher in overweight/obese patients (2.65 per 100 person-years) compared to lean patients (1.09 per 100 person-years), and this trend persisted after stratification by the presence of aRF. Similarly, the incidence of advanced fibrosis among MASLD patients was higher in overweight/obese individuals (2.06 per 100 person-years) compared to lean counterparts (0.87 per 100 person-years), irrespective of aRF.

Conclusions: The lower incidence of MASLD in the elderly population compared to the general population underscores the importance of identifying age-specific risk factors. Overweight/obesity emerged as a robust predictor of MASLD development and advanced fibrosis. Additionally, the presence of additional cardiometabolic risk factors further increased the risk of incident MASLD and advanced fibrosis among the elderly.