What Causes Crohn's Disease?

Crohn's disease is a type of inflammatory bowel disease (IBD) that causes inflammation in your gastrointestinal tract (the passageway in your digestive system that moves through the mouth, intestines, and anus). The condition mostly affects the small and large intestines—the organs that help your body break down food.

Most people with Crohn’s disease experience a variety of symptoms that affect their quality of life, including abdominal pain and cramping, diarrhea, ulcers, loss of appetite, and malnutrition. However, symptoms are not always consistent. You may have periods when symptoms worsen (flare-ups) and periods when you have no symptoms at all (remission).

Researchers don’t currently know the exact cause of Crohn’s disease. However, many studies believe that genetics, immune system functioning, and environmental risk factors may play a role in how the disease develops and progresses.

Potential Causes of Crohn’s Disease 

While the direct cause of Crohn’s disease is unknown, researchers have identified some theories that might explain the potential causes of the condition. However, more research is still needed to find an exact cause of the condition.

Immune System Dysfunction

Researchers have studied how an overactive immune system can play a role in the disease. Some of their findings suggest that when bacteria enter the digestive system, dysfunction in your body accidentally triggers your immune system. As a result, your body can attack the healthy cells in the lining of the small and large intestines by mistake. The overactive response from your immune system can lead to inflammatory symptoms and the onset of Crohn’s disease.

Other researchers think that a problem with your immune cells may lead to the inflammatory symptoms of Crohn’s disease. The cells in your immune system are responsible for fighting pathogens (or, bacteria, viruses, and fungi that cause disease). If the immune system cells aren’t working properly to get rid of pathogens, harmful bacteria may cause the onset of symptoms.

Intestinal Problems 

Some studies have looked at intestinal problems as a potential cause of Crohn’s disease. One theory suggests that an issue with the gut microbiome—or the microorganisms in your gastrointestinal tract—may lead to symptoms. 

The gut microbiome is made up of a large group of “good” bacteria that live in the small and large intestines. The gut microbiome plays a large role in regulating your metabolism, nutrition, and overall digestion system.

Some researchers suspect that a change in the gut microbiome could lead to the development of Crohn's disease. Studies have shown that the formation of the gut microbiome looks different in people with Crohn’s disease. This alteration in the gut microbiome could be due to an imbalance of healthy bacteria in your intestines. Such a change may cause harmful bacteria to enter the intestines and produce inflammation.

Is Crohn's Disease Hereditary?

According to the National Human Genome Research Institute, approximately one in five people diagnosed with Crohn's disease have a blood relative with some type of inflammatory bowel disease.

Studies have identified several genes that can increase the risk of developing the condition. Researchers believe that mutations in genes NOD2/CARD15 and ATG161L are the most likely suspects for the development of Crohn’s disease.

• NOD2/CARD15: This gene helps control the immune system response. Studies have shown that a mutation in the NO2D/CARD15 gene can make it difficult for your immune system to fight harmful bacteria in the intestines. This mutation can produce inflammation in the small intestine. 
• ATG161L: This gene plays a role in how the immune system destroys harmful bacteria. A gene mutation can lower your immune system’s ability to fight pathogens.

It is important to note that studies involving the connection between these genes and Crohn’s disease have mostly been done among white research participants. More research needs to be done to learn how Crohn’s disease develops in and affects people from all racial demographics.

Who Can Get Crohn's Disease?

Crohn’s disease can affect anyone. However, certain demographics may have an increased risk of developing the condition.

• Age: Crohn’s disease can peak at two age ranges: between the ages of 15 and 30 and between the ages of 40 and 60.
• Ethnic background: White people receive more diagnoses of Crohn’s disease than Black and Latino people. However, this may be due to less Crohn’s disease research in nonwhite communities and racial disparities in healthcare that make it difficult for people from other ethnic backgrounds to receive a proper diagnosis and care.
• Assigned sex at birth: Studies have shown that there is no significant difference in incidence rates between people assigned male at birth and those assigned female at birth. However, some studies have found that Asian males may be more likely to develop Crohn’s disease than Asian females.

Risk Factors of Crohn’s Disease

Aside from biological and genetic factors, environmental factors may also increase the risk of developing Crohn’s disease. These risk factors include:

• Smoking cigarettes
• Eating a poor diet
• Exposure to air pollution
• Taking non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin
• Having surgery to remove your appendix

A Quick Review 

Crohn's disease is a chronic condition that affects your digestive system and the way your body processes food. The exact cause of Crohn’s disease is unknown, but researchers theorize that biological problems with the immune system and intestines can lead to the onset of symptoms.

Anyone can get Crohn’s disease, but smoking tobacco, eating a high-fat diet, and taking certain medications may increase your risk of having the condition. Having a blood relative with Crohn’s disease can also make you more likely to develop symptoms. But, knowing the risk factors can help you take steps that prevent you from developing the condition.