Long-term fracture risk among women with proven endometriosis

ObjectiveTo determine whether women with pelvic endometriosis are at increased fracture risk.DesignHistorical cohort study.SettingPopulation-based investigation using the data resources of the Rochester Epidemiology Project.Patient(s)From Olmsted County, Minnesota, 987 women with endometriosis that was first surgically visualized or histologically proven in 1970–1989.Intervention(s)None, observational study.Main Outcome Measure(s)Follow-up for fractures through complete inpatient and outpatient community medical records.Result(s)In 17,408 person-years of follow-up, 256 women experienced 449 different fractures. The cumulative incidence after 20 years (30.8%) was not elevated relative to that expected (30.6%). The independent predictors of any fracture included age (hazard ratio [HR] per 10 years: 1.61; 95% confidence interval [CI] 1.42–1.84]), corticosteroid use (HR: 2.78; 95% CI 1.48–5.24), prior hip, spine, or forearm fracture (HR: 1.82; 95% CI 1.10–3.02), and use of the selective estrogen receptor modulators, tamoxifen or raloxifene (HR: 4.34; 95% CI 2.14–8.81); physical activity was protective (HR: 0.40; 95% CI 0.18–0.88). There was no significant influence on fracture risk of surgery or other medical treatments for endometriosis.Conclusion(s)Despite reported adverse effects of treatment on bone density, there was no overall increase in long-term fracture risk in this unselected cohort of women with proven endometriosis.