1. Department of Public Health and Clinical Medicine, Sunderby Research Unit, Umeå University, Sweden
2. Department of Statistics, USBE, Umeå University, Sweden
3. Research Unit, Norrbotten Region, Luleå, Sweden
4. Department of Public Health and Clinical Medicine, Division of Family Medicine, Umeå University, Sweden
5. Department of Public Health and Clinical Medicine, Medicine, Umeå University, Sweden