1 Geriatric Research, Education, and Clinical Center, Puget Sound VA Medical Center, GRECC S-182, 1660 South Columbian Way, Seattle, WA 98108, USA.
2 Department of Medicine (Geriatrics) & Ophthalmology and the Aging Center, Duke University Medical Center, DUMC Box 3003, Durham, NC 27710, USA; Geriatric Research, Education, and Clinical Center, Durham VA Medical Center, 508 Fulton Street, 3rd floor GRECC, Durham, NC 27705, USA.
3 School of Public Health, and Portland, VA Medical Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail code: CB669, Portland, OR 97239, USA.
4 Geriatric Research, Education, and Clinical Center, Puget Sound VA Medical Center, GRECC S-182, 1660 South Columbian Way, Seattle, WA 98108, USA; Department of Psychiatry and Behavioral Sciences, University of Washington, 1959 Pacific Street, Box 356560, Seattle, WA 98195, USA. Electronic address: sthielke@u.washington.edu.