1. Division of Infectious Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.
2. Division of Gerontology, Geriatrics, and Palliative Care, University of Alabama at Birmingham, Birmingham, Alabama.
3. School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama.
4. Division of Geriatrics, Department of Medicine, University of California at San Francisco, San Francisco, California.
5. San Francisco VA Medical Center, San Francisco, California.
6. Birmingham VA Medical Center, Birmingham, Alabama.
7. Division of Preventive Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.