[1] Inst Salud Carlos III, Natl Ctr Epidemiol, Madrid, Spain
[2] Gen Directorate Publ Hlth, Valencia Breast Canc Screening Programme, Valencia, Spain
[3] Ctr Super Invest Salud Publ CSISP, Valencia, Spain
[4] Inst Publ Hlth, Navarra Breast Canc Screening Programme, Pamplona, Spain
[5] DG Salud Publ ID & I SACYL, Castilla Leon Breast Canc Screening Programme, Castilla y Leon, Spain
[6] Reg Author Hlth & Consumer Affairs, Balear Islands Breast Canc Screening Programme, Hlth Promot Women & Childhood Gen Directorate Pub, Balearic Isl, Spain
[7] Hlth Serv Aragon, Aragon Breast Canc Screening Programme, Zaragoza, Spain
[8] Catalan Inst Oncol ICO, Canc Prevent & Control Unit, Barcelona, Spain