Behavioral mediators of colorectal cancer screening in a randomized controlled 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.


CONCLUSIONS
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.
School of Public Health, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095-6900, USA. amaxwell@ucla.edu
Annette E
AE
Maxwell
Roshan
R
Bastani
Catherine M
CM
Crespi
Leda L
LL
Danao
Reggie T
RT
Cayetano
D000367:Age Factors; D000368:Aged; D001213:Asian / Q000706:statistics & numerical data*; D016009:Chi-Square Distribution; D003113:Colonoscopy / Q000379:methods; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000517:prevention & control*; D003466:Cultural Characteristics; D055088:Early Detection of Cancer / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D015438:Health Behavior / Q000208:ethnology*; D006801:Humans; D016015:Logistic Models; D015141:Los Angeles; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010353:Patient Education as Topic / Q000458:organization & administration*; D018570:Risk Assessment; D012737:Sex Factors