Participants and recruitment
BREAST CANCER
Two hundred and eighty-five women aged 25–50 were recruited in December 2019. The selection was made by convenience from a cohort of a previous study. Inclusion criteria were not having a diagnosis of breast cancer, having access to the internet via a fixed or mobile device, and signing an informed consent form to voluntarily join the study.The women were contacted by telephone to request their collaboration. The study objective and phases were explained to them during the telephone call. Those who verbally agreed to participate were sent an email with more detailed information and the informed consent form, which was completed online.Twenty-five of the women who were contacted by telephone decided not to participate. The remaining 260 were grouped according to their place of residence: Avilés (