1. Diabetes Centre, Isala Clinics, Zwolle, the Netherlands
2. Langerhans Medical Research Group, Zwolle, the Netherlands
3. Department of Internal Medicine, Isala Clinics, Zwolle, the Netherlands
4. General Practice Sleeuwijk, Sleeuwijk, the Netherlands
5. General Practice ‘t Veen, Hattem, the Netherlands
6. Department of General Practice, University of Groningen, Groningen, the Netherlands
7. Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
8. Department of Internal Medicine, University Medical Center Groningen, Groningen, the Netherlands