title: Dietary fiber and breast cancer risk: a systematic review and meta-analysis of prospective studies.
abstract: BACKGROUND
  Evidence from case-control studies suggest that dietary fiber may be inversely related to breast cancer risk, but it is unclear if this is supported by prospective data. We conducted a systematic review and meta-analysis of the evidence from prospective studies.
  
  
  METHODS
  PubMed was searched for prospective studies of fiber intake and breast cancer risk until 31st August 2011. Random effects models were used to estimate summary relative risks (RRs).
  
  
  RESULTS
  Sixteen prospective studies were included. The summary RR for the highest versus the lowest intake was 0.93 [95% confidence interval (CI) 0.89-0.98, I(2) = 0%] for dietary fiber, 0.95 (95% CI 0.86-1.06, I(2) = 4%) for fruit fiber, 0.99 (95% CI 0.92-1.07, I(2) = 1%) for vegetable fiber, 0.96 (95% CI 0.90-1.02, I(2) = 5%) for cereal fiber, 0.91 (95% CI 0.84-0.99, I(2) = 7%) for soluble fiber and 0.95 (95% CI 0.89-1.02, I(2) = 0%) for insoluble fiber. The summary RR per 10 g/day of dietary fiber was 0.95 (95% CI 0.91-0.98, I(2) = 0%, P(heterogeneity) = 0.82). In stratified analyses, the inverse association was only observed among studies with a large range (≥13 g/day) or high level of intake (≥25 g/day).
  
  
  CONCLUSIONS
  In this meta-analysis of prospective studies, there was an inverse association between dietary fiber intake and breast cancer risk.
authors.affiliation: Department of Epidemiology and Biostatistics, Imperial College, London, UK. d.aune@imperial.ac.uk
authors.forename: D
authors.initials: D
authors.lastname: Aune
authors.forename: D S M
authors.initials: DS
authors.lastname: Chan
authors.forename: D C
authors.initials: DC
authors.lastname: Greenwood
authors.forename: A R
authors.initials: AR
authors.lastname: Vieira
authors.forename: D A Navarro
authors.initials: DA
authors.lastname: Rosenblatt
authors.forename: R
authors.initials: R
authors.lastname: Vieira
authors.forename: T
authors.initials: T
authors.lastname: Norat
mesh_terms: D001943:Breast Neoplasms / Q000517:prevention & control*; D004032:Diet; D004043:Dietary Fiber / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D002523:Edible Grain; D005260:Female; D005638:Fruit; D006801:Humans; D011446:Prospective Studies; D012306:Risk; D014675:Vegetables