[1] Volda Univ Coll, Fac Social Sci & Hist, Joplassvegen 1, N-6103 Volda, Norway
[2] Alesund Hosp, More & Romsdal Hosp Trust, Dept Surg, Alesund, Norway
[3] St Olavs Univ Hosp, Ctr Obes & Innovat ObeCe, Surg Clin, Trondheim, Norway
[4] Norwegian Univ Sci & Technol NTNU, Dept Clin & Mol Med, Obes Res Grp, Fac Med & Hlth Sci, Trondheim, Norway
[5] Namsos Hosp, Nord Trondelag Hosp Trust, Surg Clin, Namsos, Norway
[6] St Olavs Univ Hosp, Norwegian Natl Advisory Unit Adv Laparoscop Surg, Surg Clin, Trondheim, Norway
[7] Volda Univ Coll, Dept Phys Educ, Volda, Norway
[8] More & Romsdal Hosp Trust, Dept Res & Innovat, Alesund, Norway
[9] NTNU, Dept Clin & Mol Med, Fac Med & Hlth Sci, Trondheim, Norway