1. Department of Public Health and Clinical Medicine, Medicine, Umeå University, Umea, Sweden;
2. Department of Medical Biosciences/Clinical Chemistry, Umeå University, Umea, Sweden;
3. Department of Statistics, USBE, Umeå University, Umea, Sweden;
4. Research Unit Skellefteå, Department of Public Health and Clinical Medicine, Umeå University, Umea, Sweden