Behavioral mediators of colorectal cancer screening intervention trial

Background. Understanding mediators for behavioral change is important for the optimization of intervention strategies. This report examines mediators of change in the context of a randomized controlled intervention trial (Los Angeles, 2004-2009) that successfully increased colorectal cancer (CRC) screening among Filipino Americans. Methods. The intervention, based on the Health Behavior Framework, targeted knowledge/awareness of CRC screening, communication with health care provider, health beliefs, social support and barriers to CRC screening. Health Behavior Framework variables were assessed at baseline and 6-month follow-up (N = 432). Variables targeted for change were tested as potential mediators of the primary outcome, self-reported receipt of CRC screening during the follow-up period, which was previously found to have increased significantly among intervention participants. Results. Consistent with the Health Behavior Framework, knowledge/awareness of CRC screening and patient-provider communication mediated receipt of screening. Increase in knowledge/awareness of CRC screening accounted for 13% (95% confidence interval 2%-24%) of the total intervention effect size, while patient-provider communication accounted for 20% (5%-36%). Combined, these two variables accounted for 28% (10%-46%) of the total effect size. Conclusion. Examining the roles of potential mediators in intervention trials may help identify constructs to target in order to enhance the effectiveness of interventions to increase screening. (C) 2010 Elsevier Inc. All rights reserved.