1. 1Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.
2. 2Winship Cancer Institute, Emory University, Atlanta, Georgia.
3. 3Division of Research, Kaiser Permanente Northern California, Oakland, California.
4. 4Department of Population Health Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.
5. 5Division of Epidemiology, School of Public Health, University of California, Berkeley, California.
6. 6Department of Population Science, American Cancer Society, Atlanta, Georgia.