title: Aspirin, nonsteroidal anti-inflammatory drug use, and risk for Crohn disease and ulcerative colitis: a cohort study.
abstract: BACKGROUND
  Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) are anti-inflammatory but have been linked in some studies to Crohn disease (CD) and ulcerative colitis (UC).
  
  
  OBJECTIVE
  To assess the association between aspirin and NSAID use and incident CD and UC.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Nurses' Health Study I.
  
  
  METHODS
  76,795 U.S. women who provided biennially updated data about aspirin and NSAID use.
  
  
  METHODS
  Incident CD and UC between 1990 and 2008 (outcome) and NSAID and aspirin use (exposure).
  
  
  RESULTS
  123 incident cases of CD and 117 cases of UC occurred over 18 years and 1,295,317 person-years of follow-up. Compared with nonusers, women who used NSAIDs at least 15 days per month seemed to have increased risk for both CD (absolute difference in age-adjusted incidence, 6 cases per 100,000 person-years [95% CI, 0 to 13]; multivariate hazard ratio, 1.59 [CI, 0.99 to 2.56]) and UC (absolute difference, 7 cases per 100,000 person-years [CI, 1 to 12]; multivariate hazard ratio, 1.87 [CI, 1.16 to 2.99]). Less frequent NSAID use was not clearly associated with risk for CD or UC, and there was no clear association between aspirin use and disease.
  
  
  CONCLUSIONS
  Cohort participants were exclusively women, most of whom were white. Aspirin and NSAID use were self-reported.
  
  
  CONCLUSIONS
  Frequent use of NSAIDs but not aspirin seemed to be associated with increased absolute incidence of CD and UC. The findings have more mechanistic than clinical implications, because the absolute incidence of CD or UC associated with NSAIDs was low and the increase in risk for CD or UC associated with NSAIDs is unlikely to alter the balance of more common and clinically significant risks and benefits associated with these agents.
  
  
  BACKGROUND
  American Gastroenterological Association, IBD Working Group, Broad Medical Research Program, and National Institutes of Health.
authors.affiliation: Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Higuchi
authors.forename: Edward S
authors.initials: ES
authors.lastname: Huang
authors.forename: Hamed
authors.initials: H
authors.lastname: Khalili
authors.forename: James M
authors.initials: JM
authors.lastname: Richter
authors.forename: Charles S
authors.initials: CS
authors.lastname: Fuchs
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Chan
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D001241:Aspirin / Q000009:adverse effects*; D003093:Colitis, Ulcerative / Q000139:chemically induced* / Q000453:epidemiology; D003424:Crohn Disease / Q000139:chemically induced* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin