Risk Factors For Ulcerative Colitis

ulcerative-colitis-risk-chartWhat Are the Causes and Risk Factors For Ulcerative Colitis?

The exact cause of ulcerative colitis is not known. It is felt that a combination of genetic predisposition, abnormal immune response and environmental triggers play a role in the development of ulcerative colitis. Genetic factors are thought to play a role because ulcerative colitis is more common in people who have a parent or sibling with the disease. However, not everyone with ulcerative colitis has other family members with the disease. Environmental factors are also thought to contribute to ulcerative colitis. A virus or bacterial infection (such as salmonella or shigella) may trigger an abnormal immune response, causing the immune system to attack the lining of the digestive tract.

Additional risk factors for developing ulcerative colitis include:

  • Age less than 30
  • Caucasian race
  • Ashkenazi Jewish ancestry1
  • Having a parent, sibling or child with ulcerative colitis2
  • Use of acne medications (isotretinoin/Accutane)3

Of note, studies show that people who have had their appendix out due to appendicitis appear to have a lower risk of ulcerative colitis4.

Genetic vs. Environmental Causes

It is estimated that 23% of the risk for ulcerative colitis is due to genetic factors while the remaining 77% of the risk is due to lifestyle and environmental factors5.

Page References

1. Loftus EV. Clinical epidemiology of inflammatory bowel disease: incidence, prevalence, and environmental influences. Gastro.2004;126(6):1504–17.
2. Gearry RB. Population-based cases control study of inflammatory bowel disease risk factors. J Gastroenterology and Hepatology. 2010; 25: 325-333
3. Crockett SD, Isotretinoin use and the risk of inflammatory bowel disease: a case-control study. Am J Gastroenterol. 2010 Sep;105(9):1986-93.
4. Rutgeerts P. Appendectomy protects against ulcerative colitis. Gastroenterology1994;106:1251-1253.
5. Brant SR, Update on the Heritability of Inflammatory Bowel Disease: The Importance of Twin Studies. Inflammatory Bowel Disease. 2011;17(1): 1-5.