1. a Department of Nursing , University of Lleida , Lleida , Spain
2. b Epidemiology Department of Health and Welfare , Generalitat de Catalunya , Lleida
3. c Department of Experimental Medicine , University of Lleida
4. d Department of Surgery , Universitary Hospital Arnau de Vilanova , Lleida , Spain
5. e Universitary Hospital Arnau de Vilanova , Lleida , Spain