A population sample of the continental United States of those aged 55-75, supplemented by an enriched sample in geographic "hot spots" identified by the National Institute for Occupational Safety and Health (NIOSH) through respiratory diseases mapping. Structured telephone interviews assessed demographics, health status, smoking exposures, and occupational histories. High risk jobs were coded using a job matrix system independent of subject report of specific exposures. Two hundred thirty-four of those with COPD, with over-sampling of those with greater severity, were followed at 12-14 months to assess health status and health services utilization, as well as decrements in quality of life.