1. Department of Epidemiology; University of Washington; Seattle WA USA
2. Division of Angiology and Haemostasis; Geneva University Hospitals; Geneva Switzerland
3. Department of Clinical Epidemiology; Leiden University Medical Center; Leiden the Netherlands
4. Department of Medicine; University of Washington; Seattle WA USA
5. Department of Biostatistics; University of Washington; Seattle WA USA
6. Department of Thrombosis and Haemostasis; Leiden University Medical Center; Leiden the Netherlands
7. Group Health Research Institute; Group Health; Seattle WA USA
8. Department of Health Services; University of Washington; Seattle WA USA
9. Department of Veterans Affairs Office of Research and Development; Seattle Epidemiologic Research and Information Center; Seattle WA USA