Posted 10/2/2006 7:01 PM (GMT -7)
Study confirms IBS linked to more diseases
By ANNE DECECCO
UPI Correspondent
WASHINGTON, Sept. 29 (UPI) -- A new study confirms previous findings that irritable bowel syndrome is linked to fibromyalgia, a chronic pain and fatigue disorder, as well as migraines and depression.
Using data from a large U.S. health plan from January 1996 through June 2002, lead researcher Dr. Alexander Cole, an epidemiologist at the I3 Drug Safety Company, and colleagues identified a group of 97,593 people with a medical claim for IBS and a group of 27,402 people who had no claims associated with the disorder.
The data was taken from eight states in the Midwest and southern parts of the United States where the health-plan membership was most highly concentrated. Almost 75 percent of the IBS group was made up of women, whereas the non-IBS group was equally divided between men and women.
The study, published in the Sept. 27 issue of BioMed Central Gastroenterology, showed 264 people out of 1,000 people in the IBS group were more likely to have any of the three disorders.
Overall, people with IBS were 60 percent more likely to suffer from at least one or more of the three disorders. In contrast, in the non-IBS group, the prevalence of having at least one of the three disorders was 118 per 1,000 people.
The study also found that people with IBS were 40 percent more likely to have depression.
"The topic itself isn't new in a clinical setting. But I wanted to use a larger, population-based setting," Cole said. "We examined a large pool of participants from the general public, which makes it different from previous studies," he said.
Based on substantial evidence that several different classes of anti-depressants are effective for treating symptoms of IBS, fibromyalgia, migraines and depression, Drs. James Hudson and Harrison Pope, professors of psychiatry at Harvard Medical School, and their colleagues developed a hypothesis in 1990 that these disorders may all be symptoms of one common and underlying condition. Since then, numerous studies have also shown results linking these disorders.
"No one knows what this postulated imbalance is at this point," Pope said. He said that there is preliminary evidence that the disorders occur frequently within the same family tree, in addition to their occurrence within one individual.
"Some sort of specific genetic locus where one gene causes the body to create an abnormal protein could ultimately lead to the disorders. Not only the co-occurrence within individuals, but also the co-aggregation within families of the disorders shows that genetics are one very likely possibility," Pope said.
Pope added that while these linked disorders have been studied before, they continue to be mysterious and that future studies might do well to examine genetic links.
One of the major limitations of the study is it is based solely on one health-insurance plan's data. The prevalence of disorders among people with IBS also may differ substantially among people with different access to healthcare.
The study's authors also write that there is ample room for disorders to be misclassified in insurance claims and that the insurance claims may not accurately reflect the severity of a given disorder. In addition, disorders are given equal weighting regardless of their duration.
Despite these limitations, Pope claims that the study is a valid contribution to the subject. When asked how practitioners can use this information to help patients, he said that doctors should have a heightened sensitivity to the co-occurrence of the disorders and ask patients if they suffer from any of their other symptoms. In addition, he suggested that anti-depressants may serve as valuable treatment.
The confirmation of this hypothesis only raises more questions, Cole said. Future studies might look at whether the association between IBS and the three disorders remains when studying sub-groups of people, he added.