1. Department of Public Health Science, Norwegian University of life sciences (NMBU), Ås, Norway, and Faculty of Health and Social Work Studies, Østfold University College, Fredrikstad, Norway
2. Norwegian University of life sciences (NMBU), Ås, Norway
3. Department of Public Health Science, Norwegian University of life sciences (NMBU), Ås, Norway
4. The Public health department, Viken County Council