Diet and stress were once believed to be responsible for Crohn’s. However, we now understand that the origins of this condition are much more complex and that Crohn’s doesn’t have a direct cause.

Research suggests that it’s an interaction of risk factors — that genetics, a malfunctioning immune response, and the environment likely all play a role in the development of the disease.

However, even with all the risk factors, a person won’t necessarily develop Crohn’s.

Scientists are convinced that genetics play a large role in the development of Crohn’s disease.

Over 160 gene locations have been identified in relationship to inflammatory bowel disease (IBD), according to research.

There’s also an overlap in genetic changes between individuals with Crohn’s disease and those with ulcerative colitis (UC).

According to the Crohn’s and Colitis Foundation of America (CCFA), studies have found that 5 to 20 percent of people with Crohn’s disease have a first-degree relative (a parent, child, or sibling) with the disease.

Race, ethnicity, and Crohn’s disease

Crohn’s disease is more common in people of Northern European, Anglo-Saxon, or Ashkenazi Jewish descent than in the rest of the population.

Ashkenazi Jewish people, who have origins in Eastern Europe, are two to four times more likely to develop an IBD than people who aren’t Jewish.

Crohn’s occurs much less frequently in central and southern Europe, and less still in South America, Asia, and Africa.

It’s beginning to occur more frequently in Black Americans and Hispanic Americans.

Per a 2011 study, conducted by Crohn’s and Colitis UK, there’s also an increase in the occurrence of IBD in Black people in the United Kingdom.

This and other evidence strongly suggest that heredity alone isn’t always responsible.

A main characteristic of Crohn’s disease is chronic inflammation.

Inflammation is the result of a working immune system and its response to outside invaders such as viruses, bacteria, parasites, and anything the body labels as foreign.

Some researchers believe that Crohn’s disease may start as a normal response to an outside invader. Then the immune system fails to shut off after the problem is resolved, resulting in chronic inflammation.

Another observation is that the lining of the intestinal tract is abnormal when there’s excess inflammation. These changes seem to interfere with how the immune system functions.

When your immune system attacks normal parts of your body, you have what’s known as an autoimmune disorder.

This abnormal intestinal lining may also have a role in the body’s overreaction to other things in the environment.

The immune system may be activated by mistaking certain protein or carbohydrate structures on some foods for an invading organism or some of your body’s own tissue.

In general, Crohn’s is more common in industrialized nations and in urban areas. One of the highest rates of Crohn’s disease in the world is seen in Canada.

People who live in northern climates also seem to have a greater chance of developing the disease. This suggests that factors such as pollution, stressors to the immune system, and a Western diet may play a role.

Researchers believe that when particular genes interact with certain things in the environment, the likelihood for developing Crohn’s disease goes up.

Other factors that may increase your chances of developing Crohn’s include:

  • Smoking. Research suggests that people who smoke are more likely to develop Crohn’s disease than nonsmokers. The increased risk is likely due to the interaction between smoking and the immune system, along with other genetic and environmental factors. Smoking also worsens symptoms in people with existing Crohn’s disease.
  • Age. Crohn’s is most commonly diagnosed in people in their late teens or 20s. However, you can be diagnosed with the condition at any age.
  • Use of oral contraceptives. Women who use oral contraceptives are almost 50 percent more likely to develop Crohn’s.
  • Certain gut bacteria. A study involving both mice and the pediatric population found that the enzyme urease affected gut bacteria. This change in gut bacteria was also associated with an increased risk of IBDs such as Crohn’s.

The following factors may aggravate Crohn’s symptoms, but they don’t increase your risk for developing the disease:

  • stress
  • diet
  • use of nonsteroidal inflammatory medications (NSAIDs)

Crohn’s disease is complex, and a specific cause isn’t really present. Given this, there’s no one thing a person can do to prevent the disease. The immune system, genetics, and the environment all play a part.

However, understanding the risk factors can help scientists target new treatments and improve the course of the disease.