Exploring the validity of the continuum of resistance model for discriminating early from late and non-uptake of colorectal cancer screening: implications for the design of invitation and reminder letters.

BACKGROUND: The continuum of resistance model contends that respondents lie at one end of a continuum and non-respondents at the other with respect to factors demonstrated to impact on screening participation.
PURPOSE: The aim of this study was to explore the validity of this model for the prediction of participation in colorectal cancer screening.
METHOD: People aged 50 to 74 years were asked to complete a survey (n = 1,250). Eligible respondents (n = 376, 30 %) were invited to complete a faecal occult blood test (FOBT). The cutoff period for the determination of participation rates was 12 weeks, with a reminder sent at 6 weeks.
RESULTS: FOBTs were returned by n = 196 people (132 within 6 weeks, 64 following a reminder). Participation was generally influenced by the same variables in both the first 6 weeks and the second 6 weeks, consistent with the continuum of resistance model. These variables were having known someone with bowel cancer and the social cognitive factor, perceptions of barriers to screening. There is a suggestion, however, that other factors may be differentially associated with early, late and non-participants.
CONCLUSION: Participation in screening appears somewhat consistent with the continuum of resistance model in that early and late participants respond to some of the same factors. This suggests that the same messages are relevant to early, late and non-screeners, but further consideration of what other factors may be influencing discrete stages of readiness to participate is necessary.