[1] Univ Bergen, Dept Publ Hlth & Primary Hlth Care, N-5018 Bergen, Norway
[2] Norwegian Inst Publ Hlth, Oslo, Norway
[3] Umea Univ, Dept Surg & Perioperat Sci, Umea, Sweden
[4] German Canc Res Ctr, Div Canc Epidemiol, D-6900 Heidelberg, Germany
[5] Inst Populat Based Canc Res, Canc Registry Norway, Oslo, Norway
[6] Lund Univ, Malmo Univ Hosp, Dept Surg, Malmo, Sweden
[7] Univ Ulm, Inst Epidemiol, Ulm, Germany
[8] Innsbruck Med Univ, Dept Med Stat Informat & Hlth Econ, Innsbruck, Austria
[9] Lund Univ, Univ Lund Hosp, Dept Surg, Malmo, Sweden
[10] Agcy Prevent & Social Med, Bregenz, Austria
[11] Umea Univ, Dept Publ Hlth & Clin Med, Umea, Sweden
[12] Umea Univ, Dept Radiat Sci, Umea, Sweden