1. Department of Internal Medicine and
2. Black Lung Program, Miners’ Colfax Medical Center, Raton, New Mexico
3. Pulmonary Function Laboratory, University of New Mexico Hospitals, Albuquerque, New Mexico; and
4. Department of Sociology, University of Maryland, Baltimore County, Baltimore, Maryland
5. Department of Family and Community Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico