title: Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study.
abstract: OBJECTIVE
  Dietary linoleic acid, an n-6 polyunsaturated fatty acid, is metabolised to arachidonic acid, a component of colonocyte membranes. Metabolites of arachidonic acid have pro-inflammatory properties and are increased in the mucosa of patients with ulcerative colitis. The aim of this investigation was to conduct the first prospective cohort study investigating if a high dietary intake of linoleic acid increases the risk of developing incident ulcerative colitis.
  
  
  METHODS
  Dietary data from food frequency questionnaires were available for 203 193 men and women aged 30-74 years, resident in the UK, Sweden, Denmark, Germany or Italy and participating in a prospective cohort study, the European Prospective Investigation into Cancer and Nutrition (EPIC). These participants were followed up for the diagnosis of ulcerative colitis. Each case was matched with four controls and the risk of disease calculated by quartile of intake of linoleic acid adjusted for gender, age, smoking, total energy intake and centre.
  
  
  RESULTS
  A total of 126 participants developed ulcerative colitis (47% women) after a median follow-up of 4.0 years (range, 1.7-11.3 years). The highest quartile of intake of linoleic acid was associated with an increased risk of ulcerative colitis (odds ratio (OR) = 2.49, 95% confidence interval (CI) = 1.23 to 5.07, p = 0.01) with a significant trend across quartiles (OR = 1.32 per quartile increase, 95% CI = 1.04 to 1.66, p = 0.02 for trend).
  
  
  CONCLUSIONS
  The data support a role for dietary linoleic acid in the aetiology of ulcerative colitis. An estimated 30% of cases could be attributed to having dietary intakes higher than the lowest quartile of linoleic acid intake.
authors.affiliation: University of East Anglia, Norwich, NR4 7TJ, UK. a.hart@uea.ac.uk
authors.forename: A
authors.initials: A
authors.lastname: Tjonneland
authors.forename: K
authors.initials: K
authors.lastname: Overvad
authors.forename: M M
authors.initials: MM
authors.lastname: Bergmann
authors.forename: G
authors.initials: G
authors.lastname: Nagel
authors.forename: J
authors.initials: J
authors.lastname: Linseisen
authors.forename: G
authors.initials: G
authors.lastname: Hallmans
authors.forename: R
authors.initials: R
authors.lastname: Palmqvist
authors.forename: H
authors.initials: H
authors.lastname: Sjodin
authors.forename: G
authors.initials: G
authors.lastname: Hagglund
authors.forename: G
authors.initials: G
authors.lastname: Berglund
authors.forename: S
authors.initials: S
authors.lastname: Lindgren
authors.forename: O
authors.initials: O
authors.lastname: Grip
authors.forename: D
authors.initials: D
authors.lastname: Palli
authors.forename: N E
authors.initials: NE
authors.lastname: Day
authors.forename: K-T
authors.initials: KT
authors.lastname: Khaw
authors.forename: S
authors.initials: S
authors.lastname: Bingham
authors.forename: E
authors.initials: E
authors.lastname: Riboli
authors.forename: H
authors.initials: H
authors.lastname: Kennedy
authors.forename: A
authors.initials: A
authors.lastname: Hart
mesh_terms: D000328:Adult; D000368:Aged; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000209:etiology*; D004032:Diet / Q000706:statistics & numerical data; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000009:adverse effects*; D004812:Epidemiologic Methods; D005060:Europe / Q000453:epidemiology; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged
chemical_list: D004042:Dietary Fats, Unsaturated; D019787:Linoleic Acid