The Effect of a Colorectal Cancer Screening Decision Aid Tailored to Lower Educational Attainment Citizens

The aim of the trial is to test the effect of a web-based decision aid (DA) on colorectal cancer (CRC) knowledge, decisional conflict, participation rate, and informed choice (evaluated based on knowledge, attitudes and actual participation). The study includes three study arms. Citizens to be recruited are identified from the Danish Civil Registration System based on residence (Central Denmark Region), age (50-74 years old), and month of birth. A random sample of 15,000 citizens born in December (invited for CRC screening through October/November/December 2017) (study arm 1+2) and 5,000 citizens born in October (invited for CRC screening in January/February 2017) (study arm 3) is identified. Citizens in study arm 1+2 will receive a baseline questionnaire assessing knowledge, attitudes, worry, and health literacy. Non respondents will receive one reminder after two weeks and after four weeks non-respondents will receive a phone call, offering them to fill out the questionnaire via the phone. Baseline questionnaire respondents are included in the study, and will be randomized into two study arms (intervention group and control group). Citizens in the intervention group will be identified in the screening IT system. Date of screening invitation and screening reminder (citizens who do not return a stool sample within 45 days of the screening invitation) is retrieved. Citizens receiving a screening reminder will receive a link for the DA. Follow-up questionnaire will be sent to all included citizens in study-arm 1+2 three months after the last screening invitation has been sent out. Citizens have six weeks to respond to the questionnaire. Study arm 3 is a historic cohort. The citizens receive only one questionnaire at the same time as the baseline questionnaires are sent out to the intervention and control groups. The citizens are included if they respond to the questionnaire within six weeks. Questionnaire reminders are sent out at two and four weeks. Data on scre