1. Dept. of Pulmonary Diseases; Radboud University Nijmegen Medical Centre; Nijmegen The Netherlands
2. Dept. of Pulmonary Diseases; Gelderse Vallei Medical Centre; Ede The Netherlands
3. Dept. of Pulmonary Diseases; Atrium Medical Centre; Heerlen The Netherlands
4. Dept. of Pulmonary Diseases; University Medical Centre Groningen and University of Groningen; Groningen The Netherlands
5. Dept. of Epidemiology, Biostatistics and Health Technology Assessment; Radboud University Nijmegen Medical Centre; Nijmegen The Netherlands
6. Dept. of Medical Psychology; Radboud University Nijmegen Medical Centre; Nijmegen The Netherlands