[1] Basque Govt, Publ Hlth Dept Gipuzkoa, San Sebastian 20003, Spain
[2] CIBERESP, Barcelona, Spain
[3] Catalan Inst Oncol ICO, Canc Epidemiol Res Programme, Unit Nutr Environm & Canc, Barcelona, Spain
[4] Publ Hlth Inst Navarra, Pamplona, Spain
[5] Murcia Hlth Council, Dept Epidemiol, Murcia, Spain
[6] Andalusian Sch Publ Hlth, Granada, Spain
[7] Publ Hlth & Hlth Planning Directorate, Asturias, Spain
[8] UAB, Dept Paediat Obstet & Gynaecol & Prevent Med, Doctoral Degree Programme, Barcelona, Spain