Effect of simple anthracite pneumoconiosis on lung mechanics.

A respiratory questionnaire was administered to 20 miners with simple anthracite coal workers' pneumoconiosis (CWP) and ten normal subjects. Lung function studies which included lung mechanics and small airways disease measurements were also performed. Seventeen of the miners admitted to having symptoms of bronchitis. No significant differences were demonstrated between the two groups for vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and three seconds (FEV3), midmaximal flow rate (FEF25-75%), and peak flow rate (PEFR). A significant decrease in the maximum expiratory flow rate at 50 percent of vital capacity (V max50%) was detected; however, this was not evident when the flow rate was corrected for lung volume. Also, there were no significant differences in lung volumes, diffusing capacity (DCO) and diffusion coefficient (DCO/TLC). The mean static expired compliance (Cstate) was significantly increased in the anthracite miners, but no difference in specific compliance (Cstate/FRC) could be demonstrated. Also, no significant differences were detected in the mean values of any of the tests of small airways disease. There is little evidence of significant alterations in lung mechanics or small airway narrowing in miners with simple anthracite pneumoconiosis.