Crohn’s disease is a chronic inflammatory bowel disease. It presents as irritation in your gastrointestinal tract anywhere from the mouth to the anus, but most commonly occurs in the small and large intestines. Researchers estimate Crohn’s disease affects up to 700,000 people in the United States.

The cause of Crohn’s disease has not been discovered. Studies suggest it could be triggered by a combination of factors that include your immune system, genetics, and the environment.

Read on to learn more about the possible causes of Crohn’s disease.

Your immune system has many types of cells. Some cells can cause inflammation, and some cells can suppress it. Normally, these cells work together to defend your body from infection.

Research suggests that this system can fall out of balance. If you have too many immune cells causing inflammation in your gastrointestinal tract, it could trigger Crohn’s disease.

Crohn’s disease is linked to a higher risk of other autoimmune and inflammatory diseases. Some of these include:

These diseases are correlated with Crohn’s disease, which means that they could be connected, but are not necessarily causes.

Genes are thought to play a role in the development of Crohn’s disease. A study published in 2017 identified 41 genes that could be associated with this disease. However, more research is needed to replicate those results to confirm such a role.

You’re more likely to develop Crohn’s disease if a close relative like a parent or sibling also has it. This suggests there might be a hereditary component.

Lactose intolerance can be a genetic trait, and there is a correlation between people with inflammatory bowel diseases and people with lactose intolerance. Again, that does not mean that it’s a cause.

The environment might affect whether someone develops Crohn’s disease.

Crohn’s is more common today in countries further from the equator, including parts of North America, Europe, Australia, and New Zealand. However, the rate of Crohn’s disease is increasing in Asia, Africa, and South America.

Crohn’s disease also appears to be more common in highly populated areas.

Researchers believe this could be explained by industrialization and the adoption of the Western diet, but more research is needed.

Food alone cannot cause Crohn’s disease, but it could be a trigger. Some high fat foods can cause inflammation. Research shows that eating inflammatory foods is associated with a higher likelihood of developing Crohn’s disease.

Inflammatory foods include:

Reducing your intake of these foods may help to prevent Crohn’s disease.

Some foods have the opposite effect and reduce inflammation. Anti-inflammatory foods include:

  • fruits
  • vegetables
  • fish oils
  • whole grains

These foods help maintain a healthy mix of gut bacteria and may prevent the development of Crohn’s disease.

Consuming dairy products is also linked to a reduced chance of developing Crohn’s disease. More research is needed, however.

According to a 2018 study, smoking cigarettes significantly increases chances of developing Crohn’s disease. People with Crohn’s who smoke are more likely to:

  • develop complications
  • require hospitalization and surgery
  • respond poorly to treatments

According to the same study, the effects of smoking have been shown to be temporary. If you have Crohn’s disease and you quit smoking, it can improve long-term results.

While the causes of Crohn’s disease are still unknown, certain factors are associated with an increased risk.

Age

Crohn’s disease can occur at any age but is usually diagnosed between ages 15 and 35. People who are over 60 years old and develop Crohn’s generally experience less severe symptoms. This might be explained by changes in the gastrointestinal tract as part of the natural aging process.

Race

A 2018 study that asked participants to self-identify their race found that participants who identified as white were significantly more likely to have inflammatory bowel diseases (IBDs), including Crohn’s disease.

They were followed by participants who identified as Black, and participants who identified as Hispanic were next. And those who identified as Asian and “other/multiple/unknown” were the least likely to have IBDs.

It important to note that the study concluded that further research is needed to better understand what caused the varied results.

Nonsteroidal anti-inflammatory drugs (NSAIDs)

NSAIDs like aspirin, ibuprofen, and naproxen are associated with increased disease activity in people with Crohn’s disease. These drugs work by altering the digestive and inflammatory processes in your body, both of which are linked to Crohn’s.

The causes of Crohn’s disease are not known, but there are some factors that have been ruled out.

  • Stress. A stressful lifestyle was once thought to be a cause of Crohn’s disease, but researchers no longer believe this to be the case. Reducing stress can be helpful in managing Crohn’s disease symptoms, however.
  • Contagions. There is no evidence to suggest that Crohn’s disease is caused by viruses, bacteria, or other pathogens. Infections in your gut could trigger Crohn’s disease depending on your genes.
  • Transmission. You cannot acquire Crohn’s disease from other people or animals.

Doctors and scientists have not yet figured out exactly what causes Crohn’s disease. Researchers believe it develops from environmental triggers interacting with your unique immune system and genes.

Age and ethnicity can affect your chances of developing Crohn’s disease, but more research is needed to determine why. Your diet, whether you smoke, and whether you take NSAIDs likely factor into determining your risk, according to research.

Speak with a primary care physician or a gastroenterologist if you believe you may have symptoms of Crohn’s disease.