Asthma and rhinitis in bakers. An epidemiological study

Abstract

Abstract The aims of the thesis were to estimate the risk for bakers to contract asthma or rhinitis. We also wanted to study the impact of exposure to flour dust and of allergic sensitisation on the risk for asthma or rhinitis. Furthermore, the relation between nasal symptoms, indices of nasal inflammation and flour dust exposure was studied.A retrospective cohort study using a mailed questionnaire comprised 2226 former baker trade school students, 931 controls from other schools and 930 population controls. This study estimated the risk for asthma or rhinitis compared with controls and relative exposure. Bakers reporting asthma (n=26) or rhinitis (n=21) and baker referents (n=44) of the cohort study participated in a clinical case-referent study, assessing the impact of sensitisation. A cross-sectional study of 12 currently flour exposed bakers evaluated the relation between nasal symptoms, inflammation and exposure.There was an approximately doubled risk for asthma in male bakers and for rhinitis in bakers of both genders. Bakers also changed job due to asthma or rhinitis more frequently than controls. An allergic disposition increased the risk for asthma or rhinitis. The risk for asthma or rhinitis increased by current exposure to inhalable flour dust at onset of disease, but not by cumulative exposure dose. Asthma and rhinitis were associated with sensitisation to common allergens, while the impact of sensitisation to flour was unclear. Bakers with nasal symptoms had more nasal inflammation as compared with bakers without such symptoms and there seems to be an association between nasal inflammation and cumulative exposure dose.It is concluded that among Swedish bakers mainly working in the 1970s and 1980s, there was an approximately doubled risk for asthma in male bakers and for rhinitis in bakers of both genders. An allergic disposition increased the risk. The risk also increased by current flour dust exposure. Sensitisation to common allergens was associated with asthma or rhinitis. There were associations between nasal symptoms, nasal inflammation and cumulative flour dust exposure.