Motivational interviewing and screening colonoscopy in high-risk individuals. A randomized controlled trial

•Motivational interviewing increases colonoscopy uptake among high-risk individuals.•Physician recommendation alone shows moderate effect on colon cancer screening use.•Motivational interviewing improves cancer risk knowledge in high-risk individuals.•Counseling methods can involve health providers to enhance colon cancer screening.•Motivational interviewing can be delivered effectively on a phone-based counseling. To measure the impact of motivational interviewing (MI) on cancer knowledge and screening practice among first degree relatives (FDRs) of patients with colon cancer. This randomized controlled trial targeted patients with colon cancer first to recruit their possible FDRs. Digit randomization of the eligible index patients into intervention or control groups resulted in allocating their belonging FDRs to the same study arm. FDRs (n = 120) in intervention arm received MI counseling on phone by a trained oncology nurse and FDRs (n = 120) in control group received standard generic information by a physician on phone. Primary outcome was the rate of documented colonoscopy in FDRs within six months after the baseline. A total of 227 FDRs were followed up, 115 in the intervention and 112 in the control group. At follow-up, the uptake of screening colonoscopy in the intervention group was 83.5% versus 48.2% in controls (crude odds ratio, 5.4; 95% confidence interval, 2.9–10.0, P