1. Department of Health Studies, University of Chicago, Chicago, Illinois.
2. Endocrine Surgery Research Program, Department of Surgery, Section of Endocrine Surgery, Pritzker School of Medicine, University of Chicago, Chicago, Illinois.
3. Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
4. Biostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.