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

Objectives-To investigate the relation between levels of cumulative exposur e to wood dust and respiratory symptoms and the occurrence of bronchial hyp erresponsiveness among beech and oak workers. Methods-114 Male woodworkers from five furniture factories and 13 male unex posed controls were examined. The unexposed control group was supplemented by 200 male historical controls. Statistical analyses were performed exclud ing and including the historical controls. Dust concentration was measured by personal sampling methods. Cumulative exposure to dust was calculated fo r 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 methachol ine bronchial challenge positive if forced expiratory volume in 1 second (F EV1) fell by greater than or equal to 20%. The linear dose-response slope w as 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 yea rs.mg/m(3) Overall, no declines in FEV, and forced vital capacity (FVC) wer e found with increasing exposures. A dose-response relation was found betwe en intensity of exposure on the one hand, and sore throat, increased preval ence of positive methacholine bronchial challenge tests, and steeper dose-r esponse slope, on the other. Conclusion-Exposure to oak and beech dust may lead to the development of so re throat and bronchial hyperresponsiveness.