Protective effect of appendectomy on the development of ulcerative colitis: matched, case-control study

Dis Colon Rectum. 1999 Mar;42(3):334-6. doi: 10.1007/BF02236349.


Purpose: Appendectomy and cigarette smoking have been suggested to reduce the chance of developing ulcerative colitis. A case-control study was undertaken to determine the relative incidence of appendectomy in patients with ulcerative colitis.

Methods: This case-control study examined the incidence of appendectomy in patients with ulcerative colitis and patients attending an orthopedic outpatient clinic.

Results: Of 100 patients with ulcerative colitis, 75 pairs were matched for age, gender, and cigarette smoking. The ulcerative colitis group had an appendectomy rate of 8 percent (6/75), compared with 21 percent in the control group (P = 0.018). The odds ratio was 3.5 (95 percent confidence interval, 1.15-10.6).

Conclusions: No previous study has examined the effect of appendectomy, controlling for cigarette smoking. This study confirms that appendectomy protects against or reduces the chance of development of ulcerative colitis. A possible immunological explanation for this effect is advanced.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Appendectomy*
  • Case-Control Studies
  • Child
  • Colitis, Ulcerative / prevention & control*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Smoking