What causes IBD?

The causes of inflammatory bowel disease (IBD) are not yet clear. However, most experts think there is a multifactorial explanation (which means several different factors play a role) which might include:

• Genes:
  • Scientists have already identified one gene, called NOD2/CARD 15, which is involved in at least 20% of Crohn’s cases. Between 15% to 20% of affected individuals may have a close relative with one of these diseases, but as yet there does not seem to be any clear-cut pattern to family inheritance.
  • Researchers have discovered that ulcerative colitis can run in families. In fact, up to 20% of people with Ulcerative Colitis have a first-degree relative (first cousin or closer) with either ulcerative colitis or Crohn’s disease. So genetics clearly plays a role, although no specific pattern has been identified.
• An inappropriate reaction by the body’s immune system
• Something in the environment

That means there is no way to predict which, if any, family members will develop Ulcerative Colitis or Crohn’s disease.

Whatever the cause is, it is thought that in ulcerative colitis and Crohn’s disease, something may prompt the immune system to “turn on,” creating inflammation in the intestines. When this inflammation doesn’t ‘turn off’ as it should do, it causes damage to the gastrointestinal tract and the symptoms of ulcerative colitis or Crohn’s disease.

One important thing is that neither ulcerative colitis nor Crohn’s disease is contagious. This means you cannot ‘catch’ the condition from anyone who has it, nor can you ‘spread it’ to others if you have it.

Possible triggers that can worsen symptoms of IBD

Although the exact cause of IBD is not clear, there are certain triggers which can cause the symptoms to get worse.

These include:

• Stress – In some people, emotional upset can lead to flare-ups of symptoms
• Lapses in taking medications/incorrect dosing of medications
• Recent use of certain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or antibiotics
• Eating certain foods – some types of food can trigger flare-ups
• Smoking – Research has shown that smoking has a negative effect in patients with Crohn’s disease. There is conflicting evidence around the effect of smoking on ulcerative colitis, but in general smoking is bad for your health.

Learn more about Living with IBD.