title: Carbohydrates, glycemic index, glycemic load, and colorectal cancer risk: a systematic review and meta-analysis of cohort studies.
abstract: BACKGROUND
  Dietary carbohydrate, glycemic index, and glycemic load are thought to influence colorectal cancer risk through hyperinsulinemia. We review and quantitatively summarize in a meta-analysis the evidence from prospective cohort studies.
  
  
  METHODS
  We searched the PubMed database for prospective studies of carbohydrate, glycemic index, and glycemic load and colorectal cancer risk, up to October 2011. Summary relative risks were estimated by the use of a random effects model.
  
  
  RESULTS
  We identified 14 cohort studies that could be included in the meta-analysis of carbohydrate, glycemic index, and glycemic load and colorectal cancer risk. The summary RR for high versus low intake was 1.00 (95% CI: 0.87-1.14, I2 = 31%) for carbohydrate, 1.07 (95% CI: 0.99-1.16, I2 = 28%) for glycemic index, and 1.00 (95% CI: 0.91-1.10, I2 = 39%) for glycemic load. In the dose-response analysis, the summary RR was 0.95 (95% CI: 0.84-1.07, I2 = 58%) per 100 grams of carbohydrate per day, 1.07 (95% CI: 0.99-1.15, I2 = 39%) per 10 glycemic index units, and 1.01 (95% CI: 0.95-1.08, I2 = 47%) per 50 glycemic load units. Exclusion of one or two outlying studies reduced the heterogeneity, but the results were similar.
  
  
  CONCLUSIONS
  This meta-analysis of cohort studies does not support an independent association between diets high in carbohydrate, glycemic index, or glycemic load and colorectal cancer risk.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, Paddington, London, W2 1PG, 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: R
authors.initials: R
authors.lastname: Lau
authors.forename: R
authors.initials: R
authors.lastname: Vieira
authors.forename: D C
authors.initials: DC
authors.lastname: Greenwood
authors.forename: E
authors.initials: E
authors.lastname: Kampman
authors.forename: T
authors.initials: T
authors.lastname: Norat
mesh_terms: D001786:Blood Glucose; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D004032:Diet / Q000009:adverse effects; D004040:Dietary Carbohydrates / Q000009:adverse effects*; D038321:Glycemic Index; D006801:Humans; D012307:Risk Factors
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates