1. Primary Care Research Unit; Vårdcentralen Värmlands Nysäter; Värmland County Sweden
2. School of Health and Medical Sciences; Örebro University; Örebro Sweden
3. Department of Health Management and Health Economy; Institute of Health and Society; University of Oslo; Oslo Norway
4. Department of Medical Sciences, Cardiology, and Uppsala Clinical Research Center; University of Uppsala; Uppsala Sweden
5. National Board of Health and Welfare; Stockholm Sweden
6. Department of Medical Epidemiology and Biostatistics; Karolinska Institutet; Stockholm Sweden
7. Regional Cancer Centre; Uppsala Sweden
8. Department of Paediatrics; Örebro University Hospital; Örebro Sweden