title: Long-term intake of dietary fat and risk of ulcerative colitis and Crohn's disease.
abstract: BACKGROUND
  Dietary fats influence intestinal inflammation and regulate mucosal immunity. Data on the association between dietary fat and risk of Crohn's disease (CD) and ulcerative colitis (UC) are limited and conflicting.
  
  
  METHODS
  We conducted a prospective study of women enrolled in the Nurses' Health Study cohorts. Diet was prospectively ascertained every 4 years using a validated semi-quantitative food frequency questionnaire. Self-reported CD and UC were confirmed through medical record review. We examined the effect of energy-adjusted cumulative average total fat intake and specific types of fat and fatty acids on the risk of CD and UC using Cox proportional hazards models adjusting for potential confounders.
  
  
  RESULTS
  Among 170,805 women, we confirmed 269 incident cases of CD (incidence 8/100,000 person-years) and 338 incident cases of UC (incidence 10/100,000 person-years) over 26 years and 3,317,338 person-years of follow-up. Cumulative energy-adjusted intake of total fat, saturated fats, unsaturated fats, n-6 and n-3 polyunsaturated fatty acids (PUFAs) were not associated with risk of CD or UC. However, greater intake of long-chain n-3 PUFAs was associated with a trend towards lower risk of UC (HR 0.72, 95% CI 0.51 to 1.01). In contrast, high long-term intake of trans-unsaturated fatty acids was associated with a trend towards an increased incidence of UC (HR 1.34, 95% CI 0.94 to 1.92).
  
  
  CONCLUSIONS
  A high intake of dietary long-chain n-3 PUFAs may be associated with a reduced risk of UC. In contrast, high intake of trans-unsaturated fats may be associated with an increased risk of UC.
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, , Boston, Massachusetts, USA.
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.forename: Hamed
authors.initials: H
authors.lastname: Khalili
authors.forename: Gauree G
authors.initials: GG
authors.lastname: Konijeti
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Higuchi
authors.forename: Punyanganie
authors.initials: P
authors.lastname: de Silva
authors.forename: Charles S
authors.initials: CS
authors.lastname: Fuchs
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: James M
authors.initials: JM
authors.lastname: Richter
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Chan
mesh_terms: D000328:Adult; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000209:etiology*; D003424:Crohn Disease / Q000453:epidemiology / Q000209:etiology*; D004034:Diet Surveys; D004041:Dietary Fats / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D057566:Self Report; D014481:United States / Q000453:epidemiology
chemical_list: D004041:Dietary Fats
keywords: Crohn's Disease; Diet; Dietary Factors; Ulcerative Colitis