Association Between Phase Angle as an Indicator of Sarcopenia and Steatotic Liver Disease in the General Population

Background: Steatotic liver disease (SLD) and sarcopenia are lifestyle-related conditions for which prevention is critical. The phase angle, which is derived from impedance, reactance, and resistance values obtained via bioelectrical impedance analysis, has emerged as a potential marker of sarcopenia. Additionally, amino acids have been implicated in the pathogenesis of both SLD and sarcopenia. This epidemiological study investigated the association between SLD and sarcopenia in a general population cohort. Methods: This cross-sectional study included 281 participants with metabolic dysfunction-associated steatotic liver disease (MASLD), 72 with metabolic alcohol-associated liver disease (MetALD), and 54 with alcohol-associated liver disease (ALD). Associations between phase angle, Mac-2-binding protein glycosylation isomer (M2BPGi) as a marker of liver fibrosis, and serum amino acid levels were analyzed. Results: The phase angle was significantly higher in the MetALD group than in the MASLD and ALD groups. Multivariate analysis identified MASLD as an independent risk factor for a low phase angle compared with MetALD. M2BPGi levels were lower in MetALD than in MASLD, and M2BPGi showed a negative correlation with the phase angle. Furthermore, MetALD was characterized by lower serine and glutamine levels than MASLD, with serine demonstrating a negative correlation with the phase angle. Conclusions: Although the possibility of residual confounding factors cannot be excluded, the present study suggests that phase angle may serve as a sensitive marker for the early decline in muscle mass in patients with SLD, comparable to grip strength and skeletal muscle mass index.