[1] Univ Autonoma Barcelona, Dept Gastroenterol, Hosp Santa Creu & St Pau, Inst Recerca IIB St Pau, Barcelona 08041, Spain
[2] Univ Autonoma Barcelona, Dept Pharmacol, Hosp Santa Creu & St Pau, Inst Recerca IIB St Pau, Barcelona 08041, Spain
[3] Univ Oxford, Musculoskeletal Epidemiol Unit, NDORMS, Oxford, England
[4] Univ Autonoma Barcelona, GREMPAL Res Grp, Idiap Jordi Gol, Barcelona 08041, Spain
[5] CIBERhed Inst Carlos III, Madrid, Spain