Association Between Endometriosis/Uterine Fibroids and Premature Mortality: Findings from the NHANES 1999–2006 Data

Background: Previous research on endometriosis and uterine fibroids has primarily focused on single-disease analyses and specific health outcomes. This investigation examined potential links between both conditions and early mortality. Methods: The analysis was based on the NHANES data in a prospective cohort design, with 5402 female participants grouped based on self-reported medical histories. Standardized interview questionnaires were used to gather baseline demographic characteristics and disease-related covariates. We conducted weighted Cox proportional hazards analyses, performing both unadjusted and adjusted regression models. Further stratification was conducted to examine potential variations across subgroups. Results: A total of 273 premature deaths were recorded. Endometriosis was significantly associated with premature mortality in the unadjusted model (hazard ratio [HR] = 2.15, 95% confidence interval (CI) 1.35–3.42), with persistent significance after demographic adjustment (HR = 1.68, 95% CI 1.08–2.60) and full adjustment (HR = 1.77, 95% CI 1.15–2.75). Uterine fibroids showed initial significance (unadjusted HR = 1.77, 95% CI 1.18–2.68) but were weakened after demographic adjustment (adjusted HR = 1.07, 95% CI 0.69–1.66). Subgroup analysis results indicated that the risk of premature mortality in patients with endometriosis varied significantly across different populations. The significance was elevated in individuals with less than a high school education (HR = 2.99, 95% CI 1.53–5.84) and nondrinkers (HR = 2.45, 95% CI 1.27–4.73) in the stratified analysis of uterine fibroids. No other significant interactions were observed. Conclusions: Our study demonstrated that endometriosis independently contributes to heightened premature death risk. The link between uterine fibroids and premature mortality presents risk patterns specific to subgroups.