ABSTRACT
RATIONALE: Male participation in screening for bowel cancer is sub-optimal. Theory-based interventions provide a means of improving screening uptake. OBJECTIVE: To test the efficacy of modifying consumer invitation material in line with continuum and stage theories of health behaviour on screening participation. METHODS: N = 9216 Australian men aged 50-74 years were randomised to one of four trial arms in a 2 × 2 factorial design randomised controlled trial. Participants received either standard invitation material (control group), or combinations of modified advance-notification and invitation letters. A subsample completed baseline and endpoint behavioural surveys. RESULTS: Participants who received the modified advance notification letter were 12% more likely to screen than those who received the standard version (RR = 1.12, χ(2)(1) = 10.38, p = 0.001). The modified invitation letter did not impact screening uptake (RR = 0.97, χ(2)(1) = 0.63, p = 0.424). No significant changes in psychological variables due to the intervention were observed. CONCLUSION: Modifications to advance notification letters in line with health behaviour theories significantly improves screening uptake in men. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12612001122842 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=362688.
