1 Centre of Research & Education in General Practice, Department of Public Health, University of Copenhagen, Faculty of Health Sciences, Copenhagen, Denmark.
2 Region Zealand, Primary Health Care Research Unit.
3 Center for Medicine and the Media, The Dartmouth Institute for Health Policy and Clinical Practice, Dartmouth Medical School, Lebanon, New Hampshire, USA.
4 Centre for Evidence-Based Medicine, Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.