[1] Univ Barcelona, Sch Nursing, St Joan de Deu Fundacio Privada, Campus Docent, Barcelona, Spain
[2] Hosp Santa Creu & Sant Pau, Dept Epidemiol, Ibero Amer Cochrane Ctr, Barcelona, Spain
[3] Univ Pompeu Fabra, Dept Expt & Hlth Sci, Barcelona, Spain
[4] Univ Vic Univ Cent Catalunya, Sch Med, Vic, Spain