Railroad workers with pleural plaques: II. Small airway dysfunction among asbestos-exposed workers.

Increased volume of trapped gas (VTG) was found in 87 asbestos-exposed railroad repair shop workers, divided into three subgroups according to smoking habits. All the examined subjects had pleural plaques. Determination of VTG was used to study function of small airways. Increased VTG was found among asbestos-exposed smokers as well as nonsmokers. In both groups the VTG:TLC ratio was elevated compared with controls. Increased VTG is a sign of small airways dysfunction. In asbestos-exposed subjects, it might be caused by an early peribronchial reaction to inhaled asbestos fibers.