title: Longitudinal predictors of colorectal cancer screening among participants in a randomized controlled trial.
abstract: OBJECTIVE
  Few studies use longitudinal data to identify predictors of colorectal cancer screening (CRCS). We examined predictors of (1) initial CRCS during the first year of a randomized trial, and (2) repeat CRCS during the second year of the trial among those that completed FOBT in Year 1.
  
  
  METHODS
  The sample comprised 1247 participants of the Systems of Support to Increase Colorectal Cancer Screening (SOS) Trial (Group Health Cooperative, August 2008 to November 2011). Potential predictors of CRCS were identified with logistic regression and included sociodemographics, health history, and validated scales of psychosocial constructs.
  
  
  RESULTS
  Prior CRCS (OR 2.64, 95% CI 1.99-3.52) and intervention group (Automated: OR 2.06 95% CI 1.43-2.95; Assisted: OR 4.03, 95% CI 2.69-6.03; Navigated: OR 5.64, 95% CI 3.74-8.49) were predictors of CRCS completion at Year 1. For repeat CRCS at Year 2, prior CRCS at baseline (OR 1.97, 95% CI 1.25-3.11), intervention group (Automated: OR 9.27, 95% CI 4.56-18.82; Assisted: OR 11.17, 95% CI 5.44-22.94; Navigated: OR 13.10, 95% CI 6.33-27.08), and self-efficacy (OR 1.32, 95% CI 1.00-1.73) were significant predictors.
  
  
  CONCLUSIONS
  Self-efficacy and prior CRCS are important predictors of future screening behavior. CRCS completion increased when access barriers were removed through interventions.
authors.affiliation: Center for Health Promotion and Prevention Research, The University of Texas School of Public Health, Houston, TX, USA.
authors.forename: Caitlin C
authors.initials: CC
authors.lastname: Murphy
authors.affiliation: Center for Health Promotion and Prevention Research, The University of Texas School of Public Health, Houston, TX, USA. Electronic address: sally.w.vernon@uth.tmc.edu.
authors.forename: Sally W
authors.initials: SW
authors.lastname: Vernon
authors.affiliation: Center for Health Promotion and Prevention Research, The University of Texas School of Public Health, Houston, TX, USA.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Haddock
authors.affiliation: Group Health Research Institute, Seattle, WA, USA.
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Anderson
authors.affiliation: Group Health Research Institute, Seattle, WA, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Chubak
authors.affiliation: Group Health Research Institute, Seattle, WA, USA.
authors.forename: Beverly B
authors.initials: BB
authors.lastname: Green
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000523:psychology; D055088:Early Detection of Cancer / Q000523:psychology / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020377:Self Efficacy
keywords: Behavioral intervention research; Cancer screening; Colorectal cancer; Longitudinal study