UC Risk Factors
The causes of ulcerative colitis are not yet known, but complex associations have been identified. As Dr. McGreal described, the role of genetics has been carefully studied, and exposures to infections, toxins, and foods have also been investigated.
Race/Ethnicity
It had been assumed for some time that whites were at a much higher risk of UC than blacks or Hispanics. However this conclusion has been called into question, and may have falsely arisen because natural history studies of UC had been performed in areas with very few minorities, such as Rochester, MN, Manitoba, Canada, and Scandinavia. Recent data has shown that the UC rates for blacks and Hispanics is more similar to whites than previously thought.
Socioeconomic Status
UC is predominantly a disease of the developed world, and even in underdeveloped nations it is more common in people of higher socioeconomic status. Some experts theorize that UC is caused by an infection. While people exposed to lots of germs during their youth develop tolerance to such “infections”, those not exposed until an older age may develop a vigorous unregulated immune response, and the disease we call “UC”.
Foods
There is no consistent evidence that any particular food, such as milk, carbohydrates, or alcohol, causes UC or UC flares, although many people with and without UC have symptoms caused by consuming certain foods, such as dairy, a result of lactose intolerance. Likewise, there is not conclusive evidence that a restricted diet can cure the disease or adequately control it long term.
Tobacco
Cigarette smoking plays a significant role in the development of UC. Smoking decreases the risk of ulcerative colitis by about 50%, but quitters have a jump in risk to almost twice the risk of the general population. Some former smokers with UC who do not respond well to medicines have an impressive response when they restart smoking (although we avoid recommending this for obvious reasons). Nicotine therapy with patches, pills and enemas has not been effective and limited by side effects, suggesting that the protective effect of smoking cigarettes may be a chemical other than nicotine.
Appendectomy
Patients who undergo appendectomy have a low rate of UC. While the removal of the appendix may decrease the amount of immune tissue in the intestine, appendectomy may be a marker of some other, unidentified, factor, which puts this group at lower risk.
While I do not recommend that we do away with indoor plumbing, start smoking, or have elective appendectomies just to decrease UC risk, it is one of many reasons that kids may use to justify a romp in the mud.