1. Department of General and Digestive Surgery, Hospital Universitario Jerez de la Frontera, Ronda de Circunvalación s/n, 11407 Jerez de la Frontera, Spain
2. Department of Hematology, Hospital Universitario Puerta del Mar, Ana de Viya, 21, 11009 Cádiz, Spain
3. Preventive Medicine and Public Health Department, Faculty of Medicine, University of Seville, Av. Sanchez Pizjuan s/n, 41009 Seville, Spain
4. Department of Building Constructions II, Higher Technical School of Building Engineering, University of Seville, Avda. de la Reina Mercedes, 4A, 41012 Seville, Spain
5. Occupational Risk Prevention Unit, Virgen Macarena Hospital, Avda. Dr. Fedriani 3, 41009 Seville, Spain
6. Department of Preventive Medicine, Virgen Macarena Hospital, Avda. Dr. Fedriani 3, 41009 Seville, Spain