A health action process approach for developing invitee endorsed interventions to increase mail-out bowel cancer screening

Theory-based, user-informed interventions are needed to increase the low participation rates of population-based faecal occult blood test (FOBT) bowel cancer screening. This study investigated the theoretical fit of the health action process approach (HAPA) for home FOBT screening and measured screening invitees' attitudes towards different intervention strategies. A cross-sectional sample (n = 377), aged 50-74 years, participated in this study. Two scales were created for this study. The process approach to mail-out screening (PAMS) scale measured HAPA constructs, and the user ratings of mail-out screening interventions (UR-MSI) scale measured attitudes towards different intervention strategies. Structural equation modelling was used to assess the fit of PAMS scale responses to the HAPA model, and descriptive statistics were calculated for UR-MSI responses. PAMS results showed acceptable model fit, CFI = .968, RMSEA = .050 and explained 49.9% of the variation in FOBT screening participation. Positive ratings of interventions ranged from 20.47%, an intervention prompting planning to complete the FOBT kit, to 72.25%, an intervention promoting the positive health outcome associated with FOBT screening. Intervention strategies should be combined such that they target all factors specified within the HAPA model. User-informed intervention design should be used to effectively facilitate FOBT uptake in the community.