Background: In recent years, we have gained better knowledge about the influence of indoor environments on respiratory symptoms and asthma. The purpose of this study was to examine certain exposures in the home environment and the risk of adult-onset asthma.
Methods: A nested case-referent study of adult-onset asthma was performed in a random population sample (n = 15813), aged 20-50 years. Cases for the study included subjects reporting "physician-diagnosed" asthma (n= 174). The referents (n = 870) were randomly selected from the whole population sample. The case-referent sample was investigated with a comprehensive mailed questionnaire about exposures in the home environment, asthma, respiratory symptoms, smoking habits, and atopy. Odds ratios (OR) with 95% confidence intervals (CI) were calculated while controlling for age, sex, smoking, and atopy.
Results: Increased adjusted OR for asthma were associated with exposure to molds (OR 2.2, 95%, CI 1.4-3.5), environmental tobacco smoke (OR 2.4, 95%, CI 1.4-4.1), and the presence of a wood stove (OR 1.7, 95% CI 1.2-2.5).
Conclusions: This population-based case-referent study indicates that self-reported domestic exposures to molds or environmental tobacco smoke can be associated with adult-onset asthma.