Intervention Mediators in a Randomized Controlled Trial to Increase Colonoscopy Uptake Among Individuals at Increased Risk of Familial Colorectal Cancer.

BACKGROUND

Understanding the pathways by which interventions achieve behavioral change is important for optimizing intervention strategies.

PURPOSE

We examined mediators of behavior change in a tailored-risk communication intervention that increased guideline-based colorectal cancer screening among individuals at increased familial risk.

METHODS

Participants at increased familial risk for colorectal cancer (N = 481) were randomized to one of two arms: (1) a remote, tailored-risk communication intervention (Tele-Cancer Risk Assessment and Evaluation (TeleCARE)) or (2) a mailed educational brochure intervention.

RESULTS

Structural equation modeling showed that participants in TeleCARE were more likely to get a colonoscopy. The effect was partially mediated through perceived threat (β = 0.12, p < 0.05), efficacy beliefs (β = 0.12, p < 0.05), emotions (β = 0.22, p < 0.001), and behavioral intentions (β = 0.24, p < 0.001). Model fit was very good: comparative fit index = 0.95, root-mean-square error of approximation = 0.05, and standardized root-mean-square residual = 0.08.

CONCLUSION

Evaluating mediating variables between an intervention (TeleCARE) and a primary outcome (colonoscopy) contributes to our understanding of underlying mechanisms that lead to health behavior change, thus leading to better informed and designed future interventions.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov , NCT01274143.