1. Department of Neurology, University of California, San Francisco
2. San Francisco Veterans Affairs Medical Center, San Francisco, California
3. California Pacific Medical Center Research Institute, San Francisco
4. Department of Epidemiology and Biostatistics, University of California, San Francisco
5. Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
6. Centre for Aging SMART, Vancouver Coastal Health Research Institute and the University of British Columbia, Vancouver, Canada
7. Kaiser Permanente Center for Health Research, Portland, Oregon
8. Department of Psychiatry, University of California, San Francisco