Symptoms, airway responsiveness, and exposure to dust in beech and oak wood workers

Objectives-To investigate the relation between levels of cumulative exposure to wood dust and respiratory symptoms and the occurrence of bronchial hyperresponsiveness among beech and oak workers. Methods-114 Male woodworkers from five furniture factories and 13 male unexposed controls were examined. The unexposed control group was supplemented by 200 male historical controls. Statistical analyses were performed excluding and including the historical controls. Dust concentration was measured by personal sampling methods. Cumulative exposure to dust was calculated for each woodworker by multiplying the duration of the work by the intensity of exposure (years.mg/m(3)). Bronchial hyperresponsiveness was assessed by the methacholine bronchial challenge test. Subjects were labelled methacholine bronchial challenge positive if forced expiratory volume in 1 second (FEV1) fell by greater than or equal to 20%. The linear dose-response slope was calculated as the last dose divided by the total dose given. Results-443 Dust samples were collected. The median cumulative exposure to dust was 110 years.mg/m(3) with lower and upper quartiles at 70 and 160 years.mg/m(3) Overall, no declines in FEV, and forced vital capacity (FVC) were found with increasing exposures. A dose-response relation was found between intensity of exposure on the one hand, and sore throat, increased prevalence of positive methacholine bronchial challenge tests, and steeper dose-response slope, on the other. Conclusion-Exposure to oak and beech dust may lead to the development of sore throat and bronchial hyperresponsiveness.