1. School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.
2. Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama.
3. Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.
4. Division of Geriatrics, Department of Medicine, University of California at San Francisco, San Francisco, California.
5. Jewish Home of San Francisco Center for Research on Aging, San Francisco, California.
6. Division of Infectious Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.