[Long-term radiology and respiratory function study following exposure to asbestos]

During the supervision of 93 workers in an asbestos factory pulmonary function tests and radiographs were performed using the same equipment and by the same team, at 5 yearly intervals. The assessment of radiographic changes was judged by following both the reader of the films and the technique used (either un-named films or simultaneous films at 5 yearly intervals). On reading un-named films the appraisal of parenchymal abnormalities was variable from one reader to another; on the other hand they were less marked for simultaneous readings made by the same observer. Progressive pulmonary function tests showed that the fall in vital capacity and of VEMS in 5 year intervals was more rapid when there was a parenchymal abnormality, when the duration of exposure was long or the subject was older when first exposed. The results showed that in spite of ceasing to be exposed the parenchymal abnormalities progressed.