1. Department of Medical Psychology; Radboud University Medical Center; P.O. Box 9101 6500 HB Nijmegen the Netherlands
2. Institute of Psychology, Health, Medical and Neuropsychology Unit; Leiden University; P.O. Box 9555 2300 RB Leiden the Netherlands
3. Department of Laboratory Medicine; Radboud University Medical Center; P.O. Box 9101 6500 HB Nijmegen the Netherlands
4. Department of Dermatology; Radboud University Medical Center; P.O. Box 9101 6500 HB Nijmegen the Netherlands
5. Department of Rheumatology; Sint Maartenskliniek; P.O. Box 9011 6500 GM Nijmegen the Netherlands
6. Department for Health Evidence; Radboud University Medical Center; P.O. Box 9101 6500 HB Nijmegen the Netherlands
7. Department of Rheumatology; Radboud University Medical Center; P.O. Box 9101 6500 HB Nijmegen the Netherlands