1. Department of Circulation and Medical Imaging; Norwegian University of Science and Technology; Trondheim Norway
2. Department of Internal Medicine; Aalesund Hospital; Aalesund Norway
3. Division of Medicine; Department of Public health and Clinical Medicine; Faculty of Medicine; Umeå University; Umeå Sweden
4. Department of Thoracic- and Occupational Medicine; Trondheim University Hospital; Trondheim Norway