1. COPD Center, Department of Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Gothenburg, Sweden;
2. Department of Internal Medicine and Clinical Nutrition and
3. Division of Medicine/The OLIN Unit, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden; and
4. Center of Registers Västra Götaland, Gothenburg, Sweden
5. School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden;