1. Department of Epidemiology and Biostatistics; UCSF; San Francisco CA USA
2. Department of Quantitative Health Sciences; University of Massachusetts Medical School; Worcester MA USA
3. National Heart, Lung, and Blood Institute; Bethesda MD USA
4. Department of General Internal Medicine; Inselspital; University of Bern; Bern Switzerland
5. Department of Health Behavior; University of Alabama at Birmingham School of Public Health; Birmingham AL USA
6. Center for Surgical Medical and Acute Care Research; Birmingham VA Medical Center; Birmingham AL USA
7. Division of Preventive Medicine; University of Alabama at Birmingham School of Medicine; Birmingham AL USA
8. Department of Ambulatory and Community Medicine; University Hospital, Lausanne; Lausanne Switzerland