1. National Heart, Lung, and Blood Institute's Framingham Heart Study; 73 Mt Wayte Ave. Framingham MA 01702 USA
2. Department of Cardiology; Rennes University Hospital; Rennes France
3. Department of Cardiology; Medical University of Graz; Graz Austria
4. Cardiology Section and section of Preventive Medicine and Epidemiology, Department of Medicine; Boston University School of Medicine; Boston MA USA