[1] Univ So Denmark, Ctr Natl Clin Databases, Odense Univ Hosp, DK-5000 Odense C, Denmark
[2] Univ So Denmark, Res Unit Clin Epidemiol, Inst Clin Res, Odense C, Denmark
[3] Univ So Denmark, Dept Surg Gastroenterol A, Odense Univ Hosp, Odense C, Denmark
[4] Univ So Denmark, Res Unit Surg Gastroenterol, Inst Clin Res, Odense C, Denmark
[5] Univ So Denmark, Dept Med Gastroenterol S, Odense Univ Hosp, Odense C, Denmark
[6] Univ So Denmark, Res Unit Med Gastroenterol, Inst Clin Res, Odense C, Denmark