[1] Univ Coll Gjovik, Dept Hlth Technol & Soc, Gjovik, Norway
[2] Univ Oslo, Ctr Med Eth, N-0316 Oslo, Norway
[3] Vestfold Hosp Trust, Morbid Obes Ctr, Vestfold, Norway
[4] Univ Oslo, Inst Clin Med, N-0316 Oslo, Norway
[5] Oslo Univ Hosp Ulleval, Dept Gastrointestinal Surg, Oslo, Norway