Relevance of airflow obstruction and mucus hypersecretion to mortality.

A group of 2,065 gold miners surveyed between 1968 and 1970 was followed to 31 December 1986, at which date 859 were known to be dead. The relationship between airways obstruction and mucus hypersecretion to causes of mortality was analyzed. Airways obstruction was strongly related to mortality from chronic obstructive pulmonary disease (COPD), lung cancer, coronary heart disease and other causes. After standardization for airways obstruction, mucus hypersecretion was not related to mortality from COPD but remained related to mortality from ischaemic heart disease (IDH) and other causes, even after adjustment for tobacco smoking and dust exposure. Mucus hypersecretion was not related to mortality from lung cancer when standardized for airways obstruction.