title: Dietary fibre and risk of colorectal cancer in the Breast Cancer Detection Demonstration Project (BCDDP) follow-up cohort.
abstract: BACKGROUND
  The hypothesis that increased intake of dietary fibre lowers the risk of colorectal cancer (CRC) has recently been weakened by results from cohort and intervention studies that did not detect such an association. We investigated the association between dietary fibre intake and risk of CRC in a cohort of women that prospectively answered a food frequency questionnaire (FFQ).
  
  
  METHODS
  We studied 45 491 women in the Breast Cancer Detection Demonstration Project (BCDDP) follow-up cohort. A 62-item FFQ was administered from 1987 and 1989 to assess dietary intake. Participants received follow-up questionnaires (in 1992-1995 and 1995-1998) on which they reported incident cancers. Cases were also identified through searches of the National Death Index and state cancer registries. Cox proportional hazard regression was used to generate risk ratios and 95% CI for quintiles of total fibre intake and fibre subtypes.
  
  
  RESULTS
  During a mean follow-up time of 8.5 years we identified 487 colorectal cancer cases. The 10th and 90th percentiles of dietary fibre intake were 5.4 g and 18.2 g respectively. For total fibre we observed no association with colorectal cancer (fifth versus first quintile, RR = 0.94, 95% CI: 0.71-1.23). Analyses by subgroup of fibre and by anatomical subsite did not reveal any stronger inverse associations.
  
  
  CONCLUSIONS
  Within a cohort of older women characterized by a relatively low fibre intake, there was little evidence that dietary fibre intake lowers the risk of colorectal cancer.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, 20892, USA. bmai@epi.umaryland.edu
authors.forename: Volker
authors.initials: V
authors.lastname: Mai
authors.forename: Andrew
authors.initials: A
authors.lastname: Flood
authors.forename: Ulrike
authors.initials: U
authors.lastname: Peters
authors.forename: James V
authors.initials: JV
authors.lastname: Lacey
authors.forename: Catherine
authors.initials: C
authors.lastname: Schairer
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000209:etiology* / Q000517:prevention & control; D004043:Dietary Fiber / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors