1. Population Health Research Institute, Hamilton Health Sciences—General Site, McMaster University, 237 Barton St. E amilton, Ontario, Hamilton, CanadaL8L 2X2
2. Department of Biostatistics, University of Washington, Seattle, Washington, USA
3. Allgemeines Krankenhaus, St. Georg, Hamburg, Germany
4. National Heart, Lung and Blood Institute, Bethesda, Maryland, USA
5. Henderson Research Group, McMaster University, Hamilton, Canada