Low-to-moderate alcohol consumption is associated with increased fibrosis in individuals with metabolic dysfunction-associated steatotic liver disease.

Background & Aims: Both metabolic dysfunction and alcohol consumption cause steatotic liver disease (SLD). The distinction between metabolic dysfunction-associated SLD (MASLD) and MetALD categories is based on arbitrary thresholds of alcohol intake. Thus, we assessed the impact of different levels of alcohol consumption on SLD severity and their interaction with metabolic comorbidities.

Methods: We performed a population-based study with transient elastography (FibroScan®) data from participants in Spain (derivation cohort) and the US (validation cohort). A controlled attenuation parameter ≥275 dB/m was used to define SLD. At least one cardiometabolic risk factor was required to define MASLD. Among patients with MASLD, low alcohol consumption was defined as an average of 5-9 drinks/week, moderate consumption as 10-13 drinks/week for females and 10-20 drinks/week for males, and increased alcohol intake (MetALD) as 14-35 drinks/week for females and 21-42 drinks/week for males. Significant fibrosis was defined as a liver stiffness measurement ≥8 kPa and at-risk metabolic dysfunction-associated steatohepatitis (MASH) as a FAST score ≥0.35.

Results: The derivation cohort included 2,227 individuals with MASLD (9% reported low, 14% moderate alcohol consumption) and 76 cases with MetALD. Overall prevalences of significant fibrosis and at-risk MASH were 7.6% and 14.8%, respectively. In the multivariable analysis, alcohol consumption was independently associated with significant fibrosis and at-risk MASH. A dose-dependent increase in the prevalence of significant fibrosis and at-risk MASH was observed between the number of drinks/week and the number of cardiometabolic factors. The validation cohort included 1,732 participants with MASLD, of whom 17% had significant fibrosis and 13% at-risk MASH. This cohort validated the association between moderate intake and MASLD at risk of progression (odds ratio 1.69, 95% CI 1.06-2.71).

Conclusions: Moderate alcohol intake is commonly seen in MASLD and increases the risk of advanced disease to a level similar to that observed in MetALD.

Impact And Implications: Metabolic risk factors such as overweight, diabetes or dyslipidemia, and alcohol consumption can cause liver disease. These factors frequently coexist, but their joint effects on liver fibrosis remain uncertain. In this study, we have analyzed individuals from the general population with MASLD (metabolic dysfunction-associated steatotic liver disease) enrolled in Spain and the US. We show that moderate alcohol consumption has a supra-additive effect with metabolic risk factors, exponentially increasing the risk of liver fibrosis. These results suggest that there are no safe limits of daily alcohol intake in patients with unhealthy metabolic status and MASLD.