Thigh Muscles and Metabolic Dysfunction-Associated Steatotic Liver Disease: Findings From the SCAPIS/IGT-Microbiota Study

Background and Aims

The relationship between skeletal muscle features and hepatic fat infiltration remains understudied. To address this knowledge gap, a cross-sectional observational study was conducted using data from two ancillary studies of the SCAPIS cohort.

Method

The study aimed to examine the relationship between skeletal thigh muscle radiodensity (Hounsfield Units, HU) and area (cm²), and metabolic dysfunction-associated steatotic liver disease (MASLD) and hepatic radiodensity (HU). Multivariable linear regression analyses were applied to data from 4620 participants (52% women) with a mean age of 57.9 years. Adjustments for confounders were computed in four theoretical models.

Results

Results showed a positive significant association between thigh muscle area and MASLD (OR = 1.29, 95% CI 1.02, 1.62, p = 0.033), and a negative association with hepatic radiodensity (B = −0.76, 95% CI −1.19, −0.34, p = 0.001), independent of muscle radiodensity. Additionally, a significant association was observed between muscle radiodensity and hepatic radiodensity (B = 0.37, 95% 0.09, 0.64, p = 0.008). Finally, sex differences were notable in the association between thigh muscle area and MASLD (F-test = 0.10). Specifically, we observed statistically significant associations between thigh muscle features and liver density/MASLD in men, but not in women.

Conclusion

Conclusively, increased thigh muscle volume was associated with greater odds of MASLD and hepatic steatosis, independent of muscle radiodensity. Yet, greater thigh muscle radiodensity was associated with decreased odds of hepatic steatosis, regardless of the muscle volume. Furthermore, a sex difference was observed in our study, underscoring the importance of considering sex-specific factors on the development of MASLD.