NEW YORK (Reuters Health) - People who have had their appendix removed are more likely to develop the digestive disorder Crohn's disease, results of a new study suggest.
It's not clear if appendicitis increases the risk of Crohn's disease, or if people at risk for Crohn's disease are more likely to develop appendicitis. However, the findings may help shed light on both conditions, according to the lead author of the study, Dr. Roland E. Andersson.
"The importance of the study is that it links appendicitis, which is a common disease, with Crohn's disease, which is a rare disease," Andersson, of County Hospital Ryhov in Jonkoping, Sweden, told Reuters Health.
The study "opens a new field for research," he said, because "if we can understand appendicitis, we may also increase our understanding of Crohn's disease."
Crohn's disease is a type of inflammatory bowel disease with symptoms that include pain, abdominal cramps, diarrhea, bleeding and weight loss. Drugs and surgery to remove the portion of the intestine affected by the disease may relieve symptoms, but there is no cure.
No one knows for sure what causes appendicitis, Andersson said. Although some people think that the condition develops when a person does not get enough fiber, this connection has not been proven, he said.
Some studies have suggested that people with ulcerative colitis, another type of inflammatory bowel disease, are less likely than people without the disease to have ever had an appendectomy.
This has led some people to believe that "taking away the appendix will change your immune system so that you will be protected against ulcerative colitis," Andersson said. He noted that some doctors are even trying appendectomy as a treatment for ulcerative colitis.
The current study, which is reported in the January issue of the journal Gastroenterology, found that people who had their appendix removed were 47% more likely to develop Crohn's disease than those who did not have the surgery. However, the risk of developing the relatively rare condition was still low overall.
The increased risk was present not only soon after surgery, but also 10 years later.
It may seem odd that appendectomy is associated with a decreased risk of ulcerative colitis but an increased risk of Crohn's disease since both are inflammatory bowel diseases. The apparent contradiction "makes sense," though, according to Andersson. He explained that ulcerative colitis and Crohn's disease are marked by opposite inflammatory responses.
The study compared more than 200,000 people who had had an appendectomy and a matching group of similar people who had not had the surgery.
SOURCE: Gastroenterology 2003;124:40-46.