1. 1Department of Health Science, Division of Nursing, Luleå University of Technology, Luleå, Sweden
2. 2The OLIN study, Norrbotten County Council, Luleå, Sweden
3. 3Department of Public Health and Clinical Medicine, Division for Occupational and Environmental Medicine, The OLIN Unit, Umeå University, Umeå, Sweden
4. 4Department of Public Health and Clinical Medicine, Division of Medicine, The OLIN Unit, Umeå University, Umeå, Sweden