title: Mediation of adult fruit and vegetable consumption in the National 5 A Day for Better Health community studies.
abstract: BACKGROUND
  The 5 A Day for Better Health community studies demonstrated in randomized trials the efficacy of population-based strategies to increase fruit and vegetable consumption in diverse geographic areas and settings.
  
  
  OBJECTIVE
  Mediation analysis can help to elucidate the theoretical basis of changing dietary habits. This is important for informing more powerful cancer prevention and control interventions to achieve broad public health impact.
  
  
  METHODS
  Five sites that focused on adults were included in mediation analyses to determine whether theoretically derived constructs assessed at baseline and follow-up contributed to explaining change in fruit and vegetable (F&V) consumption. These variables were knowledge, self-efficacy, and autonomy/responsibility. Stage of change also was considered as a potential moderating variable.
  
  
  RESULTS
  Self-efficacy and knowledge of the 5 A Day recommendation increased in those who received the interventions and were positively associated with higher F&V. Mediation of intervention effect was demonstrated for these variables. Autonomy/responsibility did not meet the criteria for mediation. There was no evidence of differential effect of mediators according to baseline stage.
  
  
  CONCLUSIONS
  The present study findings provide strong support for mediation of F&V consumption by two variables: self-efficacy and knowledge. The authors discuss the findings in relation to study limitations and future research directions.
authors.affiliation: Department of Nutrition, University of North Carolina, Chapel Hill, NC 27599, USA. marci_campbell@unc.edu
authors.forename: Marci Kramish
authors.initials: MK
authors.lastname: Campbell
authors.forename: Dale
authors.initials: D
authors.lastname: McLerran
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Turner-McGrievy
authors.forename: Ziding
authors.initials: Z
authors.lastname: Feng
authors.forename: Stephen
authors.initials: S
authors.lastname: Havas
authors.forename: Glorian
authors.initials: G
authors.lastname: Sorensen
authors.forename: David
authors.initials: D
authors.lastname: Buller
authors.forename: Shirley A A
authors.initials: SA
authors.lastname: Beresford
authors.forename: Linda
authors.initials: L
authors.lastname: Nebeling
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D001294:Attitude to Health; D003430:Cross-Sectional Studies; D004032:Diet / Q000523:psychology*; D004435:Eating / Q000523:psychology; D015987:Effect Modifier, Epidemiologic; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D005638:Fruit; D006266:Health Education; D007722:Health Knowledge, Attitudes, Practice; D006293:Health Promotion; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D026684:Personal Autonomy; D011584:Psychology; D020377:Self Efficacy; D014675:Vegetables