Lung function and respiratory symptoms in silicotic and nonsilicotic gold miners.

In a cross-sectional sample of 1,973 white gold miners 45 to 54 years of age, symptoms of chronic bronchitis were equally common in men with radiologically diagnosed silicosis and those without silicosis; however, more silicotic miners complained of missing work during the previous 3 years because of chest illness. Whereas mean forced vital capacity did not differ between the 2 groups, both the 1-sec forced expiratory volume and the mean forced expiratory flow during the middle half of the forced vital capacity were significantly lower in those with silicosis. This difference was almost entirely accounted for by their higher exposure to dust in the mines. Men with silicosis, therefore, have the same or only slightly more airway obstruction than men without silicosis who have had similar total exposure to dust.