Grethe Albrektsen1, Kaare Harald Bønaa2. 1. Department of Public Health and Nursing, Faculty of Medicine and Health Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway. 2. Department of Public Health and Nursing, Faculty of Medicine and Health Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway2Department of Community Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway3Clinic for Heart Disease, St Olavs University Hospital, Trondheim, Norway.