1. Kaiser Permanente Washington Health Research Institute, Kaiser Permanente Washington, Seattle, WA, USA
2. Department of Medicine, Division of General Internal Medicine, University of Washington, Seattle, WA, USA
3. Department of Epidemiology, University of Washington, Seattle, WA, USA
4. Department of Family Medicine and Public Health, Division of Epidemiology, University of California San Diego, La Jolla, CA, USA
5. Department of Pathology, University of Washington, Seattle, WA, USA