1. Division of Injury Prevention, National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
2. Informatics, Decision-Enhancement and Analytic Sciences Center, VA Salt Lake City, Salt Lake City, Utah, USA.
3. Department of Internal Medicine, Division of Epidemiology, University of Utah School of Medicine, Salt Lake City, Utah, USA.
4. Cohen Veterans Bioscience, New York, New York, USA.
5. Department of Neurology, University of California San Francisco, San Francisco, California, USA.
6. San Francisco Veterans Affairs Medical Center, San Francisco, California, USA.
7. Departments of Epidemiology/Biostatistics and Psychiatry, University of California San Francisco, San Francisco, California, USA.