title: Zinc intake and risk of Crohn’s disease and  ulcerative colitis: a prospective cohort study.
abstract: BACKGROUND
  Diet plays a role in the pathogenesis of Crohn’s disease (CD) and ulcerative colitis (UC). Dietary zinc may influence risk of disease through effects on autophagy, innate and adaptive immune response and maintenance of the intestinal barrier.
  
  
  METHODS
  We analysed data from 170 776 women from the Nurses Health Study I and Nurses Health Study II, who were followed for 26 years. Zinc intake was assessed using semi-quantitative food frequency questionnaires administered every 4 years. Incident CD and UC were ascertained by medical record review. Cox proportional hazards models adjusting for potential confounders determined the independent association between zinc intake and incident disease.
  
  
  RESULTS
  Over 3 317 550 person-years (p-y) of follow-up, we identified 269 incident cases of CD and 338 incident cases of UC. Zinc intake ranged from 9 mg/day in the lowest quintile to 27 mg/day in the highest quintile. Compared with women with the lowest quintile of intake, the multivariate hazard ratios (HR) for CD were 0.92 [95% confidence interval (CI), 0.65 – 1.29) for women in the second quintile of intake, 0.60 (95% CI, 0.40 – 0.89) for the third quintile, 0.57 (95% CI, 0.38 – 0.86) for fourth quintile and 0.74 (95% CI, 0.50 – 1.10) for the highest quintile (Ptrend = 0.003). The association was stronger for dietary zinc (HR 0.63, 95% CI, 0.43 – 0.93, comparing extreme quintiles) than for zinc intake from supplements. Neither dietary nor supplemental zinc modified risk of UC.
  
  
  CONCLUSIONS
  In two large prospective cohorts of women, intake of zinc was inversely associated with risk of CD but not UC.
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. aananthakrishnan@mgh.harvard.edu
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.forename: Hamed
authors.initials: H
authors.lastname: Khalili
authors.forename: Mingyang
authors.initials: M
authors.lastname: Song
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Higuchi
authors.forename: James M
authors.initials: JM
authors.lastname: Richter
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Chan
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000453:epidemiology*; D003424:Crohn Disease / Q000453:epidemiology*; D004032:Diet / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D065840:Protective Factors; D014481:United States / Q000453:epidemiology; D015032:Zinc
chemical_list: D015032:Zinc