1. Department of Paediatrics Obstetrics & Gynaecology and Preventive Medicine and Public Health Universitat Autònoma de Barcelona Barcelona Spain
2. Departamento de Trabajo Social Universidad de Concepción Concepción Chile
3. Universitat Autònoma Barcelona Barcelona Spain
4. Institute of Social and Preventive Medicine University of Bern Bern Switzerland
5. Hospital Universitario Mayor Mederi Bogotá Colombia
6. Iberoamerican Cochrane Centre, Biomedical Research Institute Sant Pau (IIB SantPau) Barcelona Spain
7. CIBER de Epidemiología y Salud Pública (CIBERESP) Universitat Autònoma Barcelona Barcelona Spain