ASSOCIATION OF SILICOSIS, LUNG DYSFUNCTION, AND EMPHYSEMA IN GOLD MINERS

Background-In an earlier study of gold miners men with silicosis were found to have abnormal lung function, including airflow obstruction an d reduced diffusing capacity. In a follow up study a sample of these m en was examined by computed tomography to determine whether emphysema accounted for these abnormalities, which are associated with silicosis in this working population. Methods-A sample of 70 men from a cohort of older gold miners with and without silicosis who had worked undergr ound for a mean period of 29 years was examined by computed tomography to determine whether each man had emphysema. In addition, each man ha d lung function tests and routine chest radiography (125 kV).Results-A total of 48 men had emphysema on examination by computed tomography. On the basis of the results in a chest radiograph 55 of the men had si licosis. Emphysema was related to silicosis, being present in five of the 15 men without silicosis and in 43 of the 55 with silicosis. Diffu se emphysema was apparent in two men without silicosis (14%) and in 25 men with silicosis (45%). The proportion of men with diffuse emphysem a increased from 14% in those with International Labour Organisation c ategory 0 nodule profusion to 46% in those with category 1, 48% in tho se with category 2, and 67% in those with category 3. Emphysema was al so related to smoking: eight of the 18 who had never smoked and 40 of the 52 smokers had emphysema. All of those who had never smoked and ha d emphysema had silicosis with category 2/2 or greater nodule profusio n. Lung function tests showed changes associated with silicosis that c ould be explained by the associated emphysema. Conclusions-In this pop ulation emphysema occurred in association with silicosis and accounted for the abnormalities in lung function associated with silicosis.