1. Division of General Internal Medicine, University of California San Francisco , San Francisco, California , USA
2. Division of Geriatrics, University of California San Francisco , San Francisco, California , USA
3. San Francisco VA Healthcare System , San Francisco, California , USA
4. Family Health Care Nursing, University of California San Francisco , San Francisco, California , USA
5. Division of Immunology and Rheumatology, Stanford University , Palo Alto, California , USA
6. Psychiatry and Behavioral Sciences, Stanford University , Palo Alto, California , USA
7. Division of Oral Epidemiology and Dental Public Health, University of California San Francisco , San Francisco, California , USA