1. Norwegian Institute of Public Health Oslo Norway
2. Department of ResearchTelemark Hospital Skien Norway
3. Department of Health Management and Health Economics, Institute of Health and SocietyUniversity of Oslo Oslo Norway
4. Department of EpidemiologyHarvard School of Public Health Boston MA
5. Department of PathologyOslo University Hospital Oslo Norway
6. Department of PathologyVestfold Hospital Trust Tønsberg Norway