Asthma is associated with endometriosis: A retrospective population-based cohort study.

BACKGROUND

Evidence regarding the association between asthma and endometriosis is limited and inconsistent. The goal of the study was to investigate whether women diagnosed as having asthma were at a greater risk of endometriosis than age-matched unaffected women.

METHODS

We conducted a nationwide population-based retrospective study by using data retrieved from the Taiwan National Health Insurance Research Database during the period of 2000-2005 with follow-up through 2013. The current analysis included 7337 women aged 12-50 years with newly diagnosed asthma and using asthma-related medications and 29,348 age-matched women without asthma. A Cox proportional hazards regression model was used to estimate the risks of endometriosis in women with asthma as compared with those without asthma.

RESULTS

The overall risk of endometriosis in the asthma group was 1.50-fold higher (95% confidence interval = 1.33-1.70) than that in the nonasthma group. A stratified analysis by age further revealed that patients with asthma were associated with a higher risk of endometriosis in age groups of 21-50 years.

CONCLUSION

Compared with women without asthma, women with asthma of reproductive age are at a higher risk of endometriosis. Additional studies are warranted to elucidate the mechanism(s) underlying the association between asthma and a higher risk of endometriosis.