1. Cardiovascular Engineering, Inc, Norwood, MA (G.F.M., T.J.K., J.D.G.).
2. Boston University and NHLBI’s Framingham Study, MA (J.R., M.G.L., V.X., R.S.V.).
3. Department of Biostatistics, Boston University School of Public Health, MA (M.G.L., V.X.).
4. Preventive Medicine and Epidemiology, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, MA (V.X., R.S.V.).
5. Icelandic Heart Association, Kópavogur (S.S., V.G., T.A.).
6. Faculty of Medicine, University of Iceland, Reykjavík (V.G., T.A.).
7. Intramural Research Program, Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Baltimore, MD (L.J.L.).
8. Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University Chobanian & Avedisian School of Medicine, MA (N.M.H., R.S.V.).
9. University of Texas School of Public Health, San Antonio (R.S.V.).