Reduced skeletal muscle mass and elevated phase angle are linked to metabolic dysfunction-associated steatotic liver disease in Japanese males.

The prevalence of MASLD was 27% overall, with a higher prevalence in males than females.

• Total study population consisted of 624 participants with a median age of 46 years.
• 320 (51%) participants were male.
• Overall MASLD prevalence was 27%.
• MASLD prevalence was 38% in males and 16% in females.

Lower skeletal muscle mass index (SMI) was an independent factor for the presence of MASLD in males.

• SMI was assessed using bioelectrical impedance analysis and expressed as a skeletal muscle mass index.
• In sex-stratified multivariable logistic regression, SMI had an odds ratio of 0.33 (95% CI, 0.13–0.82; P = 0.018) for MASLD in males.
• An OR less than 1 indicates that lower SMI was associated with greater odds of MASLD.
• This relationship was not observed in females.

Elevated phase angle (PhA) was an independent factor for the presence of MASLD in males.

• PhA was measured using bioelectrical impedance analysis.
• In sex-stratified multivariable logistic regression, PhA had an odds ratio of 5.11 (95% CI, 2.14–12.77; P < 0.001) for MASLD in males.
• This positive association indicates that higher PhA was linked to greater odds of MASLD in males.
• This relationship was not observed in females.

Restricted cubic spline models demonstrated sex-specific associations between SMI and MASLD.

• Adjusted restricted cubic spline (RCS) models were used to visualize the dose-response relationship between body composition and MASLD.
• An inverse linear relationship was found between SMI and MASLD in males.
• A positive association between PhA and MASLD was also demonstrated in males.
• These relationships were not observed in females, indicating sex-specific effects of body composition on MASLD.

The study recruited university staff and faculty at Gifu University who underwent annual health checkups, with MASLD diagnosed using liver ultrasonography.

• Participants were university staff and faculty members at Gifu University.
• MASLD was diagnosed using health checkup data and liver ultrasonography findings.
• Body composition parameters including SMI, fat mass index (FMI), and PhA were measured using bioelectrical impedance analysis.
• A sex-stratified multivariable logistic regression model was the primary analytical approach.