1. Department of Population Medicine; Harvard Medical School and Harvard Pilgrim Health Care Institute; Boston MA USA
2. Meyers Primary Care Institute and University of Massachusetts Medical School; Worcester MA USA
3. Institute for Health Research; Kaiser Permanente Colorado; Denver CO USA
4. Department of Family Medicine; University of Colorado School of Medicine; Aurora CO USA
5. Division of Clinical Immunology and Rheumatology; University of Alabama at Birmingham; Birmingham AL USA
6. Division of Research; Kaiser Permanente Northern California; Oakland CA USA
7. Department of Preventive Medicine; Vanderbilt University School of Medicine; Nashville TN USA