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For Your Patients: UC--Why Me?

— Ulcerative colitis risk factors and potential triggers

Last Updated April 6, 2022
Ƶ MedicalToday
Illustration of a compass with an exclamation point inside a triangle over a colon with ulcerative colitis
Key Points

If your doctor just told you that you have ulcerative colitis (UC), you may well ask how this happened: "Was it something I ate? How could I have avoided this?"

While science has yet to provide detailed, solid answers, you should know that you almost certainly did nothing wrong. Indeed, one could say it was just bad lack, insofar as most of the factors known to affect the likelihood of developing UC are beyond the individual's control.

"Western" Lifestyle

Studies worldwide have shown that people living in industrialized countries are diagnosed with UC at much higher rates than those in less affluent nations. Furthermore, people who move to industrialized countries from poorer areas soon become just as likely to develop UC as long-time residents.

But it's not known exactly what aspect(s) of the "Western" lifestyle may be responsible: diets heavy in meat and low in fiber, or pollution, or the fast pace of life, even better access to doctors who can make a diagnosis. Some studies do suggest that diet is a particular risk factor, but no one could say your fondness for hamburgers gave you UC.

An Affected Close Relative

This is the risk factor with the strongest evidence: having a parent or sibling with UC increases the likelihood of receiving a diagnosis dramatically. But other studies have shown that the influence is limited: less than 10% of the risk can be attributed to known genetic factors. And, you can't pick your relatives!

Intestinal Bacteria

One of the hottest research areas in medicine focuses on the bacteria that colonize the intestines. Any given person hosts a variety of different intestinal bacteria and these are necessary for health digestion. But the composition of the so-called microbiome clearly goes awry in UC, and there are encouraging studies that indicate that UC may be treated, and perhaps prevented, by manipulating it.

Smoking

While smoking may cause or promote a wide range of illnesses, it actually seems to protect people from UC. (The same is true for Parkinson's disease.) In fact, it appears that smoking cessation raises the risk of developing UC. But please note: this risk is far smaller than those that smokers face from continuing the habit, and it would be foolish to start smoking as a means of preventing UC, even in those with affected family members.

Read previous installments in this series:

Part 1: What Is Ulcerative Colitis?

Part 2: I've Had Diarrhea That Won't Go Away -- What Should I Do?

"Medical Journeys" is a set of clinical resources reviewed by physicians, meant for the medical team as well as the patients they serve. Each episode of this 12-part journey through a disease state contains both a physician guide and a downloadable/printable patient resource. "Medical Journeys" chart a path each step of the way for physicians and patients and provide continual resources and support, as the caregiver team navigates the course of a disease.

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    John Gever was Managing Editor from 2014 to 2021; he is now a regular contributor.