[1] Vet Affairs Med Ctr, Ctr Chron Dis Outcomes Res 1522E, Minneapolis, MN 55417 USA
[2] Vet Affairs Med Ctr, Geriatr Res Educ & Clin Ctr, Minneapolis, MN 55417 USA
[3] Univ Minnesota, Sch Med, Dept Med, Minneapolis, MN 55455 USA
[4] Univ Minnesota, Sch Med, Div Epidemiol & Community Hlth, Minneapolis, MN 55455 USA
[5] Oregon Hlth & Sci Univ, Portland, OR 97201 USA
[6] Vet Affairs Palo Alto Hlth Care Syst, Palo Alto, CA USA
[7] Stanford Univ, Med Ctr, Palo Alto, CA 94304 USA
[8] Univ Calif San Francisco, Dept Med, Sch Med, San Francisco, CA 94143 USA
[9] Univ Calif San Francisco, Dept Epidemiol & Biostat, Sch Med, San Francisco, CA 94143 USA
[10] Univ Pittsburgh, Dept Epidemiol, Pittsburgh, PA 15261 USA