Cardio-respiratory function in United States coal workers.

Over the past five years the cardio-respiratory function of selected groups of U.S. coal workers has been intensively studied. The subjects studied included approximately 10,000 working miners at mines selected as part of an epidemiological study of the prevalence and progression of coal workers' pneumoconiosis (CWP) as well as selected groups of non-working symptomatic miners. The occupation of coal mining per se is sometimes associated with a mild reduction in ventilatory capacity which is not closely related to radiographic category of simple CWP. Slight abnormalities in gas exchange and lung mechanics appear to be associated with the higher categories of simple CWP which do not appear to affect longevity. Subjects with complicated CWP (massive fibrosis) demonstrate moderate to severe degrees of obstruction, abnormalities of gas exchange and lung mechanics that generally relate to the extent of the massive fibrosis and result in premature disability and death.