1. Department of Health, National Institute for Health and Welfare, P.O. Box 30, 00271 Helsinki, Finland
2. National Heart, Blood and Lung Institute's and Boston University's Framingham Heart Study, 73 Mt. Wayte Avenue, Suite 2, Framingham, MA 01702, USA
3. Department of Biostatistics, Boston University School of Public Health, 801 Massachusetts Avenue, Boston, MA 02118, USA
4. Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
5. Section of Preventive Medicine, Department of Medicine, Boston University School of Medicine, 801 Massachusetts Avenue, Boston, MA 02118, USA
6. Section of Cardiology, Department of Medicine, Boston University School of Medicine, 88 East Newton Street, Boston, MA 02118, USA
7. Department of Epidemiology, Boston University School of Public Health, 715 Albany Street, Boston, MA 02118, USA