People with inflammatory bowel disease commonly believe that stress can trigger their symptoms, and a new study suggests they may be right.

Canadian researchers found that among 552 bowel-disease patients they followed for a year, the risk of a symptom flare-up increased when patients were feeling particularly stressed.

The findings, reported in the American Journal of Gastroenterology, lend support to what many people with inflammatory bowel disease (IBD) have believed to be true.

IBD refers to a group of conditions marked by chronic inflammation in the intestines, leading to symptoms like abdominal pain and diarrhea. The major forms are Crohn’s disease and ulcerative colitis.

The precise cause of the conditions is unclear, but they are thought to involve an immune system overreaction that injures the body’s own intestinal tissue. While stress does not cause IBD, it is one of the environmental factors suspected of triggering symptom flare-ups in some people.

Studies show that many people with IBD feel that stress worsens their symptoms, but there has been relatively little scientific evidence of that.

“This is among the first evidence to show that the perception of stress had a direct association with disease course,” Dr. Charles N. Bernstein, the lead researcher on the new study, told Reuters Health in an email.

“We are proposing that, based on this study and other emerging data, that clinicians make more of an effort to identify and manage psychological problems and stress that patients may have,” said Bernstein, who directs the IBD Clinical and Research Centre at the University of Manitoba in Winnipeg.

The findings are based on 552 men and women with Crohn’s disease or colitis who completed surveys every three months for one year. The surveys asked about, among other things, symptom flare-ups, stressful events and perceived stress - that is, how well patients felt they could deal with their daily stresses.

Overall, 174 patients reported a symptom flare-up during the study period, meaning they had a three-month period of symptoms after having been symptom-free the previous three months.

The researchers found that patients’ risk of a symptom flare-up increased by more than two-fold when they had reported high levels of perceived stress in the preceding three-month period.

Of patients who reported a flare-up, 52 percent had had high perceived stress levels in the preceding three months, compared with 29 percent of those who remained symptom-free.

On the other hand, certain other factors suspected of triggering IBD symptoms showed no relationship to flare-ups. Those factors included use of antibiotics or non-steroidal anti-inflammatory painkillers - such as aspirin and ibuprofen - and infections such as colds, pneumonia and urinary tract infections.

There are biological reasons to believe that a person’s response to stress would trigger or worsen IBD symptoms, Bernstein and his colleagues note.

The sympathetic nervous system, which jumps into action during times of stress, acts on the lining of the colon, and might exacerbate existing inflammation. There is also evidence that stress hormones may help harmful bacteria take up residence in the intestines, which might, in turn, affect symptoms.

If stress does trigger IBD symptoms in some people, then it’s possible that learning better ways of managing stress would help stave off flare-ups. Bernstein suggested that people who feel that stress is a trigger of their symptoms talk with their doctors about it.

“Patients with IBD should feel willing to discuss stress with their physicians,” he said, adding that doctors are increasingly recognizing the effect stress may have on the disease.

SOURCE: American Journal of Gastroenterology, online April 6, 2010.