Crohn’s Disease Causes: Common Risk Factors of This Disease


Story at-a-glance

  • Health experts are still unsure on what exactly causes Crohn’s disease, although there are several theories on this subject
  • Other lifestyle factors, such as increased exposure to germ-free environments, may also play a factor in the development of this disease

Health experts are still unsure of what exactly causes Crohn’s disease, although there are several theories on this subject. Most believe that this illness is usually caused by any (or a combination of) these factors.1

Having an Abnormal Immune System

The immune system serves as the body’s protection against infections from bacteria and viruses. However, 80 percent of your immune system is located in your gut which, in turn, is home to different types of good and bad bacteria. In a healthy person, the immune system recognizes these bacteria — it allows the good bacteria to thrive, while killing off the harmful ones.

But when something disrupts the immune system, it fails to recognize these bacteria and instead sends a special protein known as tumor necrosis factor-alpha (TNF-alpha). This protein kills all the bacteria — whether good or bad. Once this happens, white blood cells build up in the gut lining, which then triggers inflammation, ulcerations and bowel injury.2

Heredity May Lead to Crohn’s Disease

Studies confirm that genetics may indeed play a role in the development of Crohn’s disease. A study published in The American Journal of Human Genetics found that as many as 200 different genes have been identified for Crohn’s disease.3 It’s also said that having a particular genetic makeup can affect the immune system’s reaction. Certain variations in these genes may also alter the way that the immune system responds to bacteria in the gut, which can therefore lead to inflammation.4

In 2009, researchers have discovered DNA variations in a gene that can increase a person’s susceptibility to developing Crohn's disease. They pinpointed DNA sequence variants in a gene region called NLRP3, which are thought to be associated with increased susceptibility to Crohn's disease. These findings were published in the journal Nature Genetics.5

Crohn’s disease can be inherited — about 20 percent of people affected by it have a close relative who has or had this illness.6 If you have an identical twin with Crohn’s then you actually have a 70 percent chance of having it as well.7 The preliminary analysis of a 2013 study involving twins also found that identical twins are more likely to both have Crohn’s disease compared to nonidentical twins.8

Acquiring a New or Having a Previous Bacterial Infection

Some genetically susceptible individuals who had a previous infection during their childhood may actually be at risk of this illness, as the infection may trigger an abnormal immune response. Some experts also believe that certain bacteria or viruses, such as E. coli and Enteroviruses, may cause inflammation that trigger this disease.9,10

Using Certain Medications

Taking nonsteroidal anti-inflammatory medications (NSAIDs) can lead to inflammation that may trigger or worsen Crohn’s disease and other inflammatory bowel diseases.11 These include ibuprofen, naproxen and aspirin.

NSAIDs lower the levels of prostaglandins in your system. Prostaglandins are hormones that perform various functions, such as causing inflammation and pain whenever your body is injured or infected. In your gut, however, prostaglandins work by controlling your acid production and giving the mucus on your gut lining protection from stomach acids.

When you have depleted levels of prostaglandins, however, you have less protection and acid, therefore irritating and inflaming your gut.12

Smoking, a Poor Diet and Other Lifestyle Factors May Predispose You to Crohn’s Disease

Smoking is probably the most controllable cause of this chronic illness. Smokers are twice as likely to develop Crohn’s disease compared to nonsmokers, and they experience more severe symptoms that usually end up requiring surgery.13

Meanwhile, although there’s no solid evidence claiming that certain foods play a role in the development of Crohn’s disease, there are speculations saying that a diet that’s generally high in refined sugars can trigger this illness and worsen its symptoms.14 This isn’t surprising, considering that refined sugars like fructose trigger insulin and leptin resistance, which are hallmark symptoms of inflammation.

Processed foods, particularly those loaded with emulsifiers, may play a role in the development of Crohn’s disease. Scientists found that these food additives may break down the mucosal lining of your gut, increasing your risk of this illness.15

Other lifestyle factors, such as increased exposure to germ-free environments, may also play a factor in the development of this disease. One theory, called the hygiene hypothesis, suggests that children who grow up in increasingly germ-free environments may have immune systems that are not fully developed.16


Crohn's Disease: Introduction

What Is Crohn's Disease?

Crohn's Disease Types

Crohn's Disease and Ulcerative Colitis

Crohn’s Disease Causes

Crohn's Disease In Children

Crohn's Disease Symptoms

Crohn's Disease Treatment

Crohn's Disease Prevention

Crohn's Disease Diet

Crohn's Disease FAQ

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Crohn's Disease and Ulcerative Colitis

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Crohn's Disease In Children

[+]Sources and References [-]Sources and References

  • 1, 7 NHS Choices, Crohn's Disease Causes, April 17, 2015
  • 2 Medical News Today, August 17, 2015
  • 3 Am J Hum Genet. 2013 Jan 10; 92(1): 107–113.
  • 4 Genetics Home Reference, Crohn’s Disease
  • 5 Nature Genetics 41, 71 - 76 (2008); December 21, 2008
  • 6 WebMD, Crohn’s Disease
  • 8 Crohn’s And Colitis UK, Twin Studies May Reveal More Information About the Genetic and Environment Factors Which Cause IBD
  • 9 The ISME Journal (2007) 1, 403–418; July 12, 2007
  • 10 Clinical and Translational Gastroenterology (2013) 4, e38; June 27, 2013
  • 11 Pharmaceuticals (Basel). 2010 Apr; 3(4): 1084–1092.
  • 12 WebMD, Can I Take NSAIDs if I Have Crohn’s Disease?
  • 13 Crohn’s And Colitis UK, Smoking and IBD
  • 14 Z Gastroenterol. 1981 Jan;19(1):1-12
  • 15 Journal of Pharmacognosy and Phytochemistry 2017; 6(3): 485-487
  • 16 Am J Gastroenterol. 2006 May;101(5):1003-4.