[1] Univ Coll London Hosp, Dept Gastroenterol, 250 Euston Rd, London NW1 2BU, England
[2] Univ Coll London Hosp, Obes Res Ctr, Dept Med, London NW1 2BU, England
[3] Busto Arstizio Hosp, Dept Gastroenterol, Milan, Italy
[4] Tor Vergata Univ, Dept Neurosci, Rome, Italy