1. Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden;
2. Department of Medicine Solna, Division of Clinical Epidemiology, Karolinska Institutet, Stockholm, Sweden;
3. Department of Epidemiology and Public Health, University College London, London, UK;
4. Department of Infectious Diseases, School of Medical Sciences, Örebro University, Örebro, Sweden;
5. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden;
6. Center of Public Health Sciences, University of Iceland, Reykjavik, Iceland;
7. Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA;
8. Hematology Clinic, Karolinska University Hospital, Stockholm, Sweden