1. Epidemiology Branch National Institutes of Environmental Health Sciences, National Institutes of Health Department of Health and Human Services Research Triangle Park North Carolina USA
2. Copenhagen Lupus and Vasculitis Clinic Rigshospitalet Copenhagen University Hospital Copenhagen Denmark
3. Division of Rheumatology, Inflammation and Immunity Brigham and Women's Hospital Harvard Medical School Boston Massachusetts USA
4. Centre for Outcomes Research and Evaluation Research Institute of the McGill University Health Centre Montreal Quebec Canada