Causes of Inflammatory Bowel Disease (IBD)

No one knows exactly what causes IBD, but these things may all play a role: an unknown virus or bacterium, heredity, and the environment. Your digestive tract may become inflamed when your body tries to fight off an invading bacterium, or the inflammation can result from the virus or bacterium itself.

The most recent data shows that rates of IBD are similar in whites and Americans of African descent, but the disease is rare in Africa itself, which points to the role of the environment. Some of the environmental factors linked to IBD are a lifestyle with little activity, higher socioeconomic status, and living in a more developed country.

Besides the environment, IBD can also run in families. About 15 to 30 percent of people with IBD have a relative with the disease. Studies are looking at whether a certain gene or group of genes makes a person more likely to get IBD. In 2001, the first gene for CD was found. An abnormal form of the gene known as Nod2 occurs twice as often in persons with CD as in the general population. In the abnormal form of this gene, some of the body's power to fight bacteria is missing, and it has been known for a long time that there is a link between bacteria in the gut and CD.

Stress does not cause IBD. As with other illnesses though, stress can worsen the symptoms of IBD. There also is no known link between eating certain kinds of foods and getting IBD, but changing your diet can help reduce symptoms and replace lost nutrients.