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The importance of non-malignant pleural fibrosis in asbestosis in relation to respiratory function is still open to debate because of the differing results obtained in studies of different population groups. In the present study we selected 50 subjects with occupational exposure to asbestos presenting mono- or bilateral pleural fibrosis at X-ray but without lung impairment. Each subject underwent bronchial lavage and ventilatory function tests. The subjects were divided into 4 groups on the basis of the degree of pleural alterations according to the ILO Classification of Pneumoconioses. The results revealed that the mean values of CV and FEV1 in each group were within physiological limits. Moreover, analysis of the type of lung function showed a normal situation in 64% and restricted function in 28% of the cases. The prevalence of the latter finding was not correlated to the severity of pleural fibrosis in the various groups. Also, comparison between severity of pleural fibrosis and number of asbestos bodies/ml of BAL liquid on the one hand and frequency of alveolitis on the other did not reveal any relationship. Therefore, the onset of pleural fibrosis appears to be independent of the quantity of inhaled asbestos fibres and due to different mechanisms from those leading to lung fibrosis. In practice, a correct interpretation of the presence of pleural fibrosis from a clinical and prognostic viewpoint also requires other investigations such as BAL and a complete respiratory function study.

The paper reports the results of a prevalence study on functional impairment and chronic bronchitis in 733 foundry workers and in a control group of 1041 workers not exposed to the specific risks of the iron and steel industry. This study is the first part of a longitudinal study lasting 5 years within the framework of the Fourth Research Programme of the European Coal and Steel Community. Data on microclimate and particulate pollution for the various departments showed uniformly cold and damp conditions. Concentrations of pollutants were generally below the current T.L.V.'s. The subjects were subdivided into groups according to age, smoking and length of exposure. All the subjects were administered the "E.C.S.C. Questionnaire for the study of chronic bronchitis and pulmonary emphysema" and underwent a chest X-ray and spirometry to measure FVC, FEV1 and Vmax 50. The prevalence of functional impairment and chronic bronchitis was higher in the foundry workers than in the group of non-exposed workers. A statistical standardization was made of the effect of age and smoking thus accentuating the effect of exposure. The results are compared with the data obtained by other epidemiologic studies on working populations exposed to a similar risk.