Surgically confirmed severe endometriosis is associated with lower risk of steatotic liver disease: Evidence of Estrogen-Linked Hepatic–Reproductive Crosstalk

Objective: The prevalence of steatotic liver disease (SLD) is rising globally, while endometriosis is a leading cause of infertility. Although links with metabolic syndrome have been reported, its relationship with SLD remains unclear. We aimed to evaluate the association between endometriosis severity and SLD. Design: A cross-sectional study. Setting: Retrospective analysis of women undergoing endometriosis surgery with documented rASRM scores at a tertiary hospital (2009–2025) and preoperative abdominal CT within 6 months. Sample: 455 patients encompassing 232 with severe endometriosis (SE, stage IV) and 223 with non-severe endometriosis (NSE). Methods: Linear and logistic regression analyses were performed to assess associations between endometriosis severity and risk factors for SLD. Main Outcome Measures: SLD assessed by liver-to-spleen Hounsfield unit ratio (LS ratio), with SLD and severe SLD defined as LS <1.0 and <0.8. The hepatic steatosis index (HSI) used for sensitivity analysis. Results: Baseline characteristics were similar between groups, except for higher estradiol levels in the SE group ( P < 0.001). The prevalence of SLD was significantly lower in SE (48.3%) compared to NSE (62.3%) ( P = 0.003), and severe SLD was also less common in SE (8.2% vs. 16.1%, P = 0.009). Patients with SLD exhibited lower estradiol levels than those without, suggesting a potential protective effect of estradiol on hepatic steatosis. Multivariate analysis confirmed that SE was independently associated with a reduced risk of SLD, irrespective of age and metabolic comorbidities. Conclusions: SE was associated with a lower prevalence of SLD, potentially mediated by higher estradiol levels.