1. From the Karolinska Institutet, Department of Medicine, Division of Hematology, Karolinska University Hospital Huddinge, Stockholm, Sweden; Karolinska Institutet, Department of Medicine, Clinical Epidemiology Unit, and Department of Pathology, Karolinska University Hospital Solna, Stockholm, Sweden; Clinical Research Centre, Örebro University Hospital, Sweden; and Department of Medicine, St Olavs Hospital, Trondheim University Hospital, Norway.