Risk factors for inflammatory bowel disease in the general population

Aliment Pharmacol Ther. 2005 Aug 15;22(4):309-15. doi: 10.1111/j.1365-2036.2005.02564.x.

Abstract

Background: The aetiology of inflammatory bowel disease remains largely unknown.

Aim: We performed a comprehensive assessment of potential risk factors associated with the occurrence of inflammatory bowel disease.

Methods: We identified a cohort of patients 20-84 years old between 1995 and 1997 registered in the General Practitioner Research Database in the UK. A total of 444 incident cases of IBD were ascertained and validated with the general practitioner. We performed a nested case-control analysis using all cases and a random sample of 10 000 frequency-matched controls.

Results: Incidence rates for ulcerative colitis, Crohn's disease, and indeterminate colitis were 11, 8, and 2 cases per 100 000 person-years, respectively. Among women, we found that long-term users of oral contraceptives were at increased risk of developing UC (OR: 2.35; 95% CI: 0.89-6.22) and CD (OR: 3.15; 95% CI: 1.24-7.99). Similarly, long-term users of HRT had an increased risk of CD (OR: 2.60; 95% CI: 1.04-6.49) but not UC. Current smokers experienced a reduced risk of UC along with an increased risk of CD. Prior appendectomy was associated with a decreased the risk of UC (OR: 0.37; 95% CI: 0.14-1.00).

Conclusions: Our results support the hypothesis of an increased risk of inflammatory bowel disease associated with oral contraceptives use and suggest a similar effect of hormone replacement therapy on CD. We also confirmed the effects of smoking and appendectomy on inflammatory bowel disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Inflammatory Agents, Non-Steroidal / adverse effects
  • Appendectomy / adverse effects
  • Aspirin / adverse effects
  • Contraceptives, Oral / adverse effects
  • Epidemiologic Methods
  • Female
  • Humans
  • Inflammatory Bowel Diseases / epidemiology*
  • Male
  • Middle Aged
  • Smoking / adverse effects
  • Smoking / epidemiology
  • Sweden / epidemiology

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Contraceptives, Oral
  • Aspirin