Sociodemographic features and patterns of non-participation in colorectal cancer screening in Finland.

BACKGROUND: Colorectal cancer (CRC) screening was run as a randomized health services programme in Finland between 2004 and 2016. This study evaluates sociodemographic features and patterns of non-participation among men and women invited to be screened.
METHODS: The study population in this register-based study includes 233 211 men and women invited to guaiac faecal occult blood test screening on consecutive screening rounds (n = 708 621 invitations). A generalized estimating equation (GEE) was used to estimate incidence rate ratios (IRR) between sociodemographic features and non-participation.
RESULTS: The overall proportion of non-participation was 31.6% and was higher in men (38.8%) than in women (24.6%). Birth cohort, education, marital status and country of birth were associated with non-participation. The birth cohort of 1950-54 was less likely to participate than the birth cohort of 1940-44. Men and women with primary education were more likely non-participants (IRR 1.26, CI 1.23-1.29 and IRR 1.22, CI 1.18-1.26, respectively) than men or women with tertiary education. Further, unmarried persons and immigrants had an increased risk of non-participation. Initial non-participation predicted subsequent behaviour, since, e.g. ∼80% of first-round non-participants also remained non-participants in the second round.
CONCLUSION: Education, gender and marital status had a significant effect on non-participation in the CRC screening programme. As high and comprehensive participation is essential for a successful screening programme, attention should be paid in ensuring participation of all sociodemographic groups. Special efforts should be invested in those not participating in the first invitational round, since initial non-participation predicts non-participation to subsequent invitations.