1. Division of Research; Kaiser Permanente Northern California; Oakland CA USA
2. Department of Dermatology; University of California at San Francisco; San Francisco CA USA
3. Department of Dermatology; Kaiser Permanente Los Angeles Medical Center; Los Angeles CA USA
4. Departments of Dermatology, Biostatistics, and Epidemiology and Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
5. Division of Clinical Immunology and Rheumatology; University of Alabama at Birmingham; Birmingham AL USA
6. Department of Medicine; University of Massachusetts Medical School, Meyers Primary Care Institute and Fallon Clinic; Worcester MA USA