[1] Univ Naples Federico II, Dept Publ Hlth, Naples, Italy
[2] Western Univ, Dept Med, Div Gastroenterol, London, ON, Canada
[3] Western Univ, Dept Epidemiol & Biostat, London, ON, Canada
[4] Lawson Hlth Res Inst, London Hlth Sci Ctr, London, ON, Canada