Sex differences in fatty liver prevalence at equivalent adiposity: a cross-sectional study of fat distribution in a health screening cohort

Fatty liver (FL) is more prevalent in men, but whether this sex disparity persists at comparable adiposity remains unclear. We examined sex-specific associations between body fat percentage (BF%) and ultrasonography-diagnosed FL and assessed the contribution of central adiposity. This cross-sectional study included 17,061 adults (8,173 women; 8,888 men) undergoing health screening in Seoul, Korea, during 2020–2025. BF% was measured by bioelectrical impedance analysis, and FL was diagnosed by ultrasonography. Logistic regression models included sex, BF%, and their interaction, followed by adjustment for waist-to-hip ratio and waist circumference. FL prevalence was 20.6% in women and 39.2% in men ( p < 0.001). At comparable BF% levels, prevalence was higher in men with 27.1% versus 1.9% at BF% 20–24.9% and 47.6% versus 4.6% at BF% 25–29.9% (both p < 0.001). Adjustment for central adiposity reduced the sex odds ratio from 15.80 to 2.30, corresponding to 69.8% attenuation; prevalence ratios decreased from 4.41 to 1.79. Among participants with FL, BMI < 23 kg/m² was more common in women (19.4% vs. 8.5%, p < 0.001), and women in this subgroup had elevated BF% (mean 33.2%). Sex differences in FL prevalence were substantially attenuated after adjustment for central adiposity, suggesting that adiposity alone may be insufficient for sex-neutral risk assessment.