title: Social Cognitive Constructs Did Not Mediate the BEAT Cancer Intervention Effects on Objective Physical Activity Behavior Based on Multivariable Path Analysis.
abstract: BACKGROUND
  Most breast cancer survivors do not meet physical activity recommendations. Understanding mediators of physical activity behavior change can improve interventions designed to increase physical activity in this at-risk population.
  
  
  OBJECTIVE
  Study aims were to determine the 3-month Better Exercise Adherence after Treatment for Cancer (BEAT Cancer) behavior change intervention effects on social cognitive theory constructs and the mediating role of any changes on the increase in accelerometer-measured physical activity previously reported.
  
  
  METHODS
  Post-treatment breast cancer survivors (N = 222) were randomized to BEAT Cancer or usual care. Assessments occurred at baseline, 3 months (M3), and 6 months (M6). Adjusted linear mixed model analysis of variance determined intervention effects on walking self-efficacy, outcome expectations, goal setting, and perceived barrier interference at M3. Path analysis determined mediation of intervention effects on physical activity at M6 by changes in social cognitive constructs during the intervention (i.e., baseline to M3).
  
  
  RESULTS
  BEAT Cancer significantly improved self-efficacy, goals, negative outcome expectations, and barriers. Total path analysis model explained 24 % of the variance in M6 physical activity. There were significant paths from randomized intervention group to self-efficacy (β = 0.15, p < .05) and barriers (β = -0.22, p < .01). Barriers demonstrated a borderline significant association with M6 physical activity (β = -0.24, p = .05). No statistically significant indirect effects were found.
  
  
  CONCLUSIONS
  Although BEAT Cancer significantly improved social cognitive constructs, no significant indirect effects on physical activity improvements 3 months post-intervention were observed (NCT00929617).
authors.affiliation: Department of Nutrition Sciences, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL, 35294, USA. ROGERSL@UAB.EDU.
authors.forename: Laura Q
authors.initials: LQ
authors.lastname: Rogers
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB, Canada.
authors.forename: Kerry S
authors.initials: KS
authors.lastname: Courneya
authors.affiliation: Department of Kinesiology, Southern Illinois University Carbondale, Carbondale, IL, USA.
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Anton
authors.affiliation: Department of Medicine, Southern Illinois University School of Medicine, Springfield, IL, USA.
authors.forename: Patricia
authors.initials: P
authors.lastname: Hopkins-Price
authors.affiliation: Statistics and Research Informatics Core, Center for Clinical Research, Southern Illinois University School of Medicine, Springfield, IL, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Verhulst
authors.affiliation: Statistics and Research Informatics Core, Center for Clinical Research, Southern Illinois University School of Medicine, Springfield, IL, USA.
authors.forename: Randall S
authors.initials: RS
authors.lastname: Robbs
authors.affiliation: Department of Psychiatry, Southern Illinois University School of Medicine, Springfield, IL, USA.
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Vicari
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: McAuley
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000523:psychology*; D015444:Exercise / Q000523:psychology*; D005260:Female; D015438:Health Behavior; D006293:Health Promotion; D006801:Humans; D008875:Middle Aged; D011582:Psychological Theory; D020377:Self Efficacy; D012944:Social Support; D017741:Survivors / Q000523:psychology; D016896:Treatment Outcome; D016138:Walking / Q000523:psychology*
keywords: Compliance; Health promotion; Mechanism; Oncology; Social cognitive theory