Reproductive Lifespan and Adult-Onset Bronchiectasis in U.S. Postmenopausal Women: An Investigation of the Women's Health Initiative Cohort.

Background: While bronchiectasis disproportionately affects postmenopausal women, the role of reproductive factors in its pathogenesis is not well characterized. We hypothesized that a shorter reproductive lifespan is associated with higher risk of bronchiectasis. Methods: We studied postmenopausal women in the Women’s Health Initiative study. The exposures included ages at menarche and menopause, and time between the 2 (reproductive lifespan). The outcome was the first incidence of bronchiectasis after Medicare enrollment, as reflected in the Medicare claims data. Incidence rates were calculated and a series of Cox proportional hazards models controlling for demographics, body mass index, smoking, oophorectomy, hormone therapy (HT), oral contraceptives, and comorbid conditions were created. Results: Cumulative incidence of bronchiectasis in the cohort of 96,996 women was 2.7%. Shorter reproductive lifespan was associated with higher bronchiectasis risk (trend Conclusion: Longer reproductive lifespan is associated with reduced risk of bronchiectasis in postmenopausal women – but only in those without a history of HT use.