ABSTRACT
PURPOSE: To analyze interventions implemented at the time of colorectal cancer (CRC) screening, or among individuals who have previously undergone investigation for CRC, focused on reducing CRC risk through promotion of lifestyle behavior change. Additionally, this review evaluated to what extent such interventions apply behavior change techniques (BCTs) to achieve their objectives. METHODS: Five databases were systematically searched to identify randomized control trials seeking to reduce CRC risk through behavior change. Outcomes were changes in health-related lifestyle behaviors associated with CRC risk, including changes in dietary habits, body mass index, smoking behaviors, alcohol consumption, and physical activity. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were pooled using random effects models. BCT's were coded from a published taxonomy of 93 techniques. RESULTS: Ten RCT's met the inclusion criteria. Greater increase in fruit/vegetable consumption in the intervention group were observed with respect to the control (SMD 0.13, 95% CI 0.08 to 0.18; p < 0.001). Across fiber, alcohol, fat, red meat, and multivitamin consumption, and smoking behaviors, similar positive outcomes were observed (SMD 0.09-0.57 for all, p < 0.01). However, among physical activity and body mass index, no difference between the intervention groups compared with controls were observed. A median of 7.5 BCTs were applied across included interventions. CONCLUSION: While magnitude of the observed effect sizes varied, they correspond to potentially important changes in lifestyle behaviors when considered on a population scale. Future interventions should identify avenues to maximize long-term engagement to promote sustained lifestyle behavior change.