The relationship between coal mining and chronic nonspecific respiratory disease.

Abstract
Two coal-mining communities, each containing about 5000 people, were studied in an attempt to see whether coal mining was related to chronic nonspecific respiratory disease. In each community persons 21 years of age and over were interviewed and a sample of 225 coal miners and their wives and 224 other manual workers (not coal miners) and their wives were invited for a physical examination. Coal miners and other manual workers were matched on what were thought to be significant variables. Physical examinations and questioning revealed a slight excess of certain respiratory symptoms among coal miners when compared with other manual workers. However, an excess was also noted among the wives of coal miners when compared with the wives of other manual workers. There was no difference in symptoms commonly associated with chronic respiratory disease, [long dash] persistent cough and phlegm and reduced forced expiratory volumes. Coal miners showed x-ray evidence of pneumoconiosis not present among other manual workers. It was concluded that while occupational exposures in connection with coal mining produce pneumoconiosis the effect of these exposures on chronic nonspecific respiratory disease is probably not very great.