Airway responsiveness to methacholine, respiratory symptoms, and dust exposure levels in grain and flour mill workers in eastern France.

Our goal was to assess the relation between dust exposure levels and the respiratory health status of workers in grain and flour mills in eastern France. We studied 118 male workers from 11 mills and 164 unexposed male controls. Dust concentration was measured by personal sampling methods. Outcome variables included respiratory symptoms, routine pulmonary function tests, and indices of airway responsiveness to methacholine. A great within- and between-area variability of inhalable dust concentration was found in all mills. A dose-response relationship was observed between dust exposure levels and chronic respiratory symptoms, suggesting that exposure to grain and flour dust may lead to chronic bronchitis. A significant relation was found between dust exposure and airway hyper-responsiveness; this finding is important since it has been hypothesized that the latter abnormality may lead to or be a predisposing factor in subsequent chronic, irreversible airflow obstruction.