[1] Vrinnevi Hosp, Dept Surg, Norrkoping, Sweden
[2] Vrinnevi Hosp, Dept Biomed & Clin Sci, Norrkoping, Sweden
[3] Karolinska Univ Hosp, Div Upper Abdominal Dis, Stockholm, Sweden
[4] Linkoping Univ, Dept Biomed & Clin Sci, Norrkoping, Sweden
[5] Karolinska Inst, Clin Epidemiol Div, Dept Med Solna, Stockholm, Sweden