The exact cause of Crohn’s disease is still unknown. However, research suggests genetics, the immune system, and environmental factors may all play a role in the development of the disease.

Crohn’s disease is a type of inflammatory bowel disease (IBD) that affects your gastrointestinal tract.

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 does not have a single, direct cause.

Keep reading to learn more about the possible causes and risk factors of Crohn’s disease.

Researchers have so far identified over 200 gene sequences that may play a role in the development of Crohn’s disease.

Some gene variations may impact the way your immune system fights bacteria in your digestive tract. This could lead to inflammation and symptoms of Crohn’s disease.

The most common immune-related genes associated with Crohn’s disease include:

  • NOD2
  • ATG16L1
  • IL23R
  • IRGM

A 2016 review suggests there’s also an overlap in genetic changes between Crohn’s disease and ulcerative colitis, which is the other type of IBD. Some genes may lead to both types of IBD.

Up to 15% of people with Crohn’s disease have a first-degree relative with the disease, such as a parent, child, or sibling.

Speak with a healthcare professional if you have a family member with Crohn’s disease and you start to experience symptoms. They could help determine whether you’re at risk of developing the condition, too.

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 are not Jewish.

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

Crohn’s disease is beginning to occur more frequently in Black Americans and Hispanic Americans. A 2024 review suggests no difference in disease progression between people of different ethnicities, but there are treatment-related differences. For example:

  • Black and Hispanic people are less likely than white people to get surgery for IBD.
  • Black and Hispanic people are more likely than white people to visit the emergency room for Crohn’s disease.

A 2021 review found that Black people were more likely than white people to report several factors that could impact access to treatment. These included transportation to medical centers and the cost of treatment.

The authors also note that Black and Hispanic people were less likely than white people to have medical insurance, or they had Medicaid. These may both be barriers to receiving medical treatment for Crohn’s disease.

People of different ethnicities may also be more likely to experience different types of Crohn’s disease. For example, white people are more likely than African American, Hispanic, and Asian people to experience Crohn’s ileitis.

Lastly, the following gene variations have also been associated with the development of Crohn’s disease among people of different ethnic or racial backgrounds:

  • Asian: TNFSF15
  • Black or African American: STAT5A, STAT53, NOD2
  • White or European descent: TPMT, HLA-DQA1*05

It’s important to note that more research is needed to fully understand how Crohn’s disease affects people of different racial and ethnic backgrounds.

The main characteristic of Crohn’s disease is chronic inflammation, which may be due to an overactive immune system attacking the body and failing to shut off.

The cause of an overactive immune system is unclear, but it may start as a normal immune response to an outside invasion by a foreign body, such as viruses, bacteria, or parasites. In other cases, inflammation may be due to a change in your gut bacteria, such as from taking antibiotics.

After the foreign invasion is cleared, the immune system may continue to attack your healthy gut cells, believing them to be foreign. This could lead to chronic inflammation.

Another theory is that changes in the gut microbiome or the permeability of the intestine may disrupt the lining of the intestine, leading to inflammation. This inflammation may then lead to additional damage to the lining of the intestine, which would perpetuate the immune response.

It’s important to note that more research is needed to fully understand the role of the immune system in Crohn’s disease, as these processes may co-occur and are interconnected.

Crohn’s disease is more common in industrialized nations, urban areas, and Northern climates, according to the Crohn’s and Colitis Foundation.

A 2019 literature review suggests the following risk factors have been associated with the development of Crohn’s disease or causing symptom flare-ups:

Taking contraceptives may also increase your risk of developing Crohn’s disease. A 2015 review found that people who use contraceptives are 50% more likely to develop Crohn’s than people who do not.

You’re also more likely to receive a diagnosis in your late teens or 20s, though you may receive a diagnosis at any age.

What is the main cause of Crohn’s disease?

The exact cause of Crohn’s disease is unknown. However, researchers suggest that genetics, environmental factors, and the immune system may all play a role in the development of the disease.

How long does someone with Crohn’s disease live?

The life expectancy for Crohn’s disease is continuing to improve. A 2020 review suggests the life expectancy for someone with Crohn’s is shorter than someone who doesn’t have the condition by 6.6–8.1 years for adult females and 5–6.1 years for adult males.

What are the 3 highest risk factors for Crohn’s disease?

There are not three specific risk factors for Crohn’s disease. A combination of genetics, environmental factors, and the immune system may contribute to disease development.

Crohn’s disease is complex, and a specific cause is not present. Given this, there’s not one thing you can do to prevent the disease. The immune system, genetics, and the environment all play a part.

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