Ambient Air Pollution and Chronic Bronchitis in a Cohort of U.S. Women

Background: Limited evidence links air pollution exposure to chronic cough and sputum production. Few reports have investigated the association between long-term exposure to air pollution and classically defined chronic bronchitis. Objectives: Our objective was to estimate the association between long-term exposure to particulate matter (diameter <10 μm, PM10; <2.5μm, PM2.5), nitrogen dioxide (NO2), and both incident and prevalent chronic bronchitis. Methods: We estimated annual average PM2.5, PM10, and NO2 concentrations using a national land-use regression model with spatial smoothing at home addresses of participants in a prospective nationwide U.S. cohort study of sisters of women with breast cancer. Incident chronic bronchitis and prevalent chronic bronchitis, cough and phlegm, were assessed by questionnaires. Results: Among 47,357 individuals with complete data, 1,383 had prevalent chronic bronchitis at baseline, and 647 incident cases occurred over 5.7-y average follow-up. No associations with inci...