1 Cochrane Associate Center of Madrid (Universidad Francisco de Vitoria-Madrid, Hospital Universitario Ramón y Cajal-IRYCIS); Department of Paediatrics, Obstetrics & Gynaecology and Preventative Medicine, UAB, Spain
2 Clinical Biostatistics Unit. Hospital Universitario Ramón y Cajal (IRYCIS), Spain
3 Independent consultant, Spain
4 Independent consultant, United Kingdom
5 Preventive medicine Unit. Hospital Universitario Ramón y Cajal, Spain
6 CIBER Epidemiology and Public Health (CIBERESP), Spain
7 Department of Paediatrics, Obstetrics & Gynaecology and Preventative Medicine. Universitat Autònoma de Barcelona, Spain
8 SEXCOMPLEX Working Group, Hospital Ramón y Cajal, Spain
9 Clinical Biostatistics Unit. Hospital Universitario Ramón y Cajal (IRYCIS)/CIBER Epidemiology and Public Health (CIBERESP), Spain