At the time of the study, Bang H. Nguyen was with the Northern California Cancer Center, Fremont, and the Division of Epidemiology, Department of Health Research and Policy, School of Medicine, Stanford University, Stanford, CA. Stephen J. McPhee and Susan L. Stewart were with the Division of General Internal Medicine, Department of Medicine, University of California, San Francisco. Hiep T. Doan was with the Northern California Cancer Center, Fremont.