Table 1_Association between body composition and metabolic dysfunction-associated steatotic liver disease in Chinese general population: a cross-sectional study stratified by sex and obesity status.docx

After adjusting for confounders, a lower FFM/FM ratio was significantly associated with higher MASLD prevalence in all subgroups except the non-obese stratum, in which the association was of similar magnitude but borderline non-significant. (males: OR = 0.47, 95% CI 0.26–0.83, p = 0.009; females: OR = 0.35, 95% CI 0.13–0.95, p = 0.039; obese: OR = 0.49, 95% CI 0.26–0.92, p = 0.028; non-obese: OR = 0.46, 95% CI 0.21–1.01, p = 0.051).

Interaction tests were not significant (sex: p = 0.554; obesity: p = 0.917). RCS revealed a linear dose–response relationship (overall p = 0.021; nonlinear p = 0.289). E-values ranged from 2.21 to 2.77, indicating robustness to unmeasured confounding.

Waist-to-hip ratio (WHR) was independently associated with MASLD only in females (OR = 1.13, 95% CI 1.04–1.22, p = 0.003), and the combined FFM/FM + WHR model achieved the highest AUC in females (0.822).</p>Conclusion<p>FFM/FM ratio shows a universal protective effect against MASLD across sex and obesity strata, while WHR has sex-specific predictive value only in women. The linear dose–response relationship supports continuous monitoring of muscle-fat balance, even in normal-weight individuals.

BIA-derived body composition analysis may assist in identifying high-risk individuals for MASLD in large-scale health check-ups.</p>