[1] Odense Univ Hosp, Dept Med Gastroenterol, DK-5000 Odense C, Denmark
[2] Royal Cornwall Hosp, Gastrointestinal Unit, Truro, Cornwall, England
[3] Dunedin Publ Hosp, Gastrointestinal Unit, Dunedin, New Zealand
[4] Univ Otago, Dunedin Sch Med, Dunedin, New Zealand
[5] Univ Otago, Dept Med, Dunedin, New Zealand
[6] Univ Glasgow, Dept Publ Hlth, Glasgow, Lanark, Scotland
[7] Glasgow Royal Infirm, Dept Gastroenterol, Glasgow G4 0SF, Lanark, Scotland