Association between chronic obstructive pulmonary disease and endometriosis: a population-based cohort study

Background: The relationship between chronic obstructive pulmonary disease (COPD) and endometriosis has been rarely explored. Aim: The present study aimed to investigate whether women with COPD have altered risk of endometriosis compared with those without COPD. Methods: We conducted a retrospective population-based cohort study by using data retrieved from the Taiwan Health Insurance Research Database. A total of 640 women aged 40–60 years who were newly diagnosed as having COPD between 2000 and 2006 were enrolled as the COPD group, and 2560 age-matched women without COPD were selected as the non-COPD group. Both the groups were followed up until the end of 2013. A Cox proportional-hazards regression model was used to estimate the endometriosis risk in women with COPD compared with those without COPD. The following confounders were considered: infertility; uterine leiomyoma; inflammatory disease of the cervix, vagina, or vulva; estrogen use; and the annual number of outpatient visits to a gynecologist. Results: Endometriosis risk in the COPD group was 3.34-fold (95% confidence interval = 1.23–9.07) higher than that in the non-COPD group after adjustment for comorbidities, estrogen use, and the annual number of outpatient visits to a gynecologist. Conclusion: Endometriosis risk is higher in women aged 40–60 years with COPD than in those without COPD. This study suggests that clinicians should be aware that COPD might be a risk factor for endometriosis. Future studies focusing on the underlying pathophysiology between COPD and endometriosis are warranted.