Crohn's disease risk factors: who is more likely to get Crohn's disease

What Crohn's disease is

Crohn's disease is a chronic disease in which abnormal reactions of the immune system cause inflammation in the digestive tract. It most often affects the small intestine and the beginning of the large intestine, but it can affect any part of the digestive tract, from the mouth to the anus (NIDDK) (MedlinePlus).

Crohn's disease is an inflammatory bowel disease (IBD). Ulcerative colitis and microscopic colitis are other common types of IBD (NIDDK). It usually begins slowly and may get worse over time; symptoms come in flares, often with periods of remission in between that can last weeks or years (NIDDK).

Researchers estimate that 1 million people in the United States have Crohn's disease, and studies show it has become more common in the United States and other parts of the world. Experts do not know why (NIDDK).

Who is more likely to get Crohn's disease

Crohn's disease can develop in people of any age or race (NIDDK). Combining the NIDDK and MedlinePlus lists, it is more likely if you (NIDDK) (MedlinePlus):

• are between the ages of 20 and 29 (NIDDK list)
• have a family member with IBD, most often a parent or sibling (NIDDK); MedlinePlus names a parent, child or sibling with Crohn's disease
• are of Jewish descent (NIDDK list)
• smoke cigarettes; smoking may double your chance of getting Crohn's disease
• take certain medicines, such as antibiotics, birth control pills and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen, which may slightly raise the chance (MedlinePlus list); NSAIDs are also a common cause of peptic ulcers
• eat a high-fat diet, which may also slightly raise the risk (MedlinePlus list)

What may cause Crohn's disease

Doctors are not sure what causes Crohn's disease (NIDDK) (MedlinePlus). Experts think these factors may play a role (NIDDK):

• An abnormal immune reaction, in which the immune system attacks bacteria that tend to live in the intestines and causes inflammation. Such reactions can be triggered by the environment, genes or the microbiome.
• Environment, meaning where and how someone lives and other factors outside the body. Researchers are still studying how it interacts with genes, the immune system and the microbiome.
• Genes. Crohn's disease sometimes runs in families, and having a parent or sibling with it may make you more likely to get it.
• The microbiome, the bacteria, viruses and fungi in the digestive tract. Studies have found differences between the microbiomes of people with and without IBD, and research is ongoing.

Stress and eating certain foods do not cause the disease, but they can make symptoms worse (MedlinePlus).

Symptoms to know

The most common symptoms are diarrhea, cramping and pain in the belly, and weight loss (NIDDK) (MedlinePlus). Other symptoms include (NIDDK) (MedlinePlus):

• anemia
• eye redness or pain
• feeling tired
• fever
• joint pain or soreness
• nausea, loss of appetite or vomiting
• skin changes such as red, tender bumps under the skin

Symptoms vary with where the inflammation is and how severe it is (NIDDK) (MedlinePlus). To diagnose it, providers use a medical and family history, a physical exam, and tests such as blood and stool tests, a colonoscopy, an upper GI endoscopy and imaging (MedlinePlus).

Possible complications

Over time, Crohn's disease may lead to anemia, low bone mass (osteopenia or osteoporosis, also linked to the corticosteroids used to treat it), malnutrition, and problems with growth and development in children (NIDDK). Serious complications that may need hospital care or surgery include intestinal blockage, fistulas, abscesses, anal fissures and ulcers (NIDDK) (MedlinePlus). Some people also have inflammation of the joints, skin, eyes, liver and bile ducts, kidneys or lungs (NIDDK). See anemia risk factors and osteoporosis risk factors.

If Crohn's disease affects the large intestine, you are more likely to get colorectal cancer, and the risk is higher the longer you have had it, or if you also have primary sclerosing cholangitis (PSC) or a family history of colorectal cancer (NIDDK). NIDDK says doctors most often recommend starting colorectal cancer screening 8 to 10 years after diagnosis in this group (NIDDK). See colorectal cancer risk factors.

There is no cure, but treatments such as medicines, bowel rest and surgery can reduce inflammation, relieve symptoms and prevent complications (MedlinePlus).

When IBS-like symptoms are checked, doctors may use a colonoscopy to check for conditions such as inflammatory bowel disease (NIDDK). See IBS risk factors.

Common questions

Is Crohn's disease the same as ulcerative colitis?

No. Both are types of inflammatory bowel disease, along with microscopic colitis (NIDDK). Crohn's disease can affect any part of the digestive tract (NIDDK).

Which risk factors can I change?

Age, family history and genes cannot be changed. Smoking is on both lists and may double the chance of getting Crohn's disease (NIDDK) (MedlinePlus); see the quit smoking check. MedlinePlus also lists some medicines and a high-fat diet as slightly raising the risk (MedlinePlus).

Does stress cause Crohn's disease?

No. Stress and certain foods can make symptoms worse but do not cause the disease (MedlinePlus). NIDDK notes that people with Crohn's disease commonly report stress, depression and anxiety (NIDDK).