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

Brumbach BH1, Birmingham WC2, Boonyasiriwat W3, Walters S4, Kinney AY5.

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Abstract

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.