Lung function studies of asbestos workers.

Pulmonary function tests have been conducted on 155 asbestos workers and 130 referents. It was found that the lung function impairment in asbestos workers is predominantly a restrictive ventilatory defect appearing even when radiographic changes are not detectable. There was, however, no evidence of airway obstruction. As the disease progressed, all the pulmonary function indices, including vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), maximal ventilation volume (MVV), total lung capacity (TLC), and pulmonary diffusing capacity (DLCO), were reduced dramatically, with the exception of FEV1.0/FVC(%). It is suggested that both radiographic examination and pulmonary function tests should be used as early detection measures of asbestos-induced lung disorders. VC, FVC, and FEV1.0 are the simplest, most reproducible, and most valid indices for the health surveillance of asbestos workers, while the FVC test is the most valuable for epidemiologic study. With stepwise regression analysis a quantitative relationship between dust exposure and pulmonary function was demonstrated. There was no significant difference in the small airway function of the exposed workers and the referents. Further study is needed to investigate the possibility of asbestos-induced small airway obstruction and to estimate the roles played by cigarette smoking and air pollution.