[1] Örebro University,Department of Surgery, Faculty of Medicine and Health
[2] Örebro University Hospital,Department of Surgery
[3] Örebro University,Clinical Epidemiology and Biostatistics, School of Medical Sciences
[4] Karolinska Institutet,Unit of Biostatistics, Institute of Environmental Medicine
[5] Karolinska Institutet,Division of Surgery, Department of Clinical Sciences, Danderyd Hospital