1. Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, Ulleråkersv. 40, 751 85 Uppsala, Sweden
2. Division of Nursing, Department of Health Sciences, University West, SE-461 86 Trollhättan, Sweden
3. Faculty of Nursing and Heath Sciences, Nord University, 8049 Bodö, Norway
4. Department of Surgical Sciences, Uppsala University Hospital, Entrance 70, 1st Floor, 751 85 SE Uppsala, Sweden