1. Division of Geriatric Medicine and Meyers Primary Care Institute, University of Massachusetts Medical School, Worcester, Massachusetts;
2. Intramural Research Program, Laboratory of Epidemiology, Demography and Biometry, National Institute on Aging, Bethesda, Maryland;
3. Icelandic Heart Association, Kopavogur, Iceland;
4. Department of Medicine, University of Iceland, Reykjavik, Iceland;
5. Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.