1. University of California, San Francisco (A.V.S., T.F.H., T.F.L., E.V., K.S., L.P., X.L.), San Francisco, California 94107
2. Icelandic Heart Association (S.S., K.S., D.O., V.G.), Kopavogur, IS 201 Iceland
3. Laboratory of Epidemiology, Demography, and Biometry (T.B.H.), Intramural Research Program, National Institute on Aging, Bethesda, Maryland 20892
4. Maine Medical Center Research Institute (C.J.R.), Scarborough, Maine 04074
5. Faculty of Medicine (G.S., V.G.), University of Iceland, Reykjavik, 101 Iceland
6. Department of Endocrinology and Metabolism (G.S.), Landspitali University Hospital, Reykjavik, 101 Iceland