[1] Katholieke Univ Leuven, Univ Psychiat Ctr, B-3070 Kortenberg, Belgium
[2] Catholic Univ Louvain, Fac Kinesiol & Rehabil Sci, B-3001 Louvain, Belgium
[3] Univ Hosp Gasthuisberg, Dept Abdominal Surg, B-3000 Louvain, Belgium
[4] Univ Birmingham, Sch Hlth & Populat Sci, Coll Med & Dent, Birmingham B15 2TT, W Midlands, England