"These studies remind us that the effects of inflammatory bowel disorders extend to every corner of the body, including the lungs and central nervous system," said Edward V. Loftus, Jr., MD, author of an editorial appearing in this month's journal and associate professor of medicine at the Mayo Clinic College of Medicine. "The findings lend credence to the concept that patients with one chronic inflammatory condition are more likely than the general population to develop another."
Inflammatory bowel disease (IBD) is a term that refers to both ulcerative colitis and Crohn's disease. According to the most recent data from the National Health Interview Survey, there are more than two million prevalent cases of Crohn's disease and more than one million cases of ulcerative colitis in the U.S.
Ulcerative colitis, a condition in which the lining of the large intestine becomes inflamed and ulcerated, most commonly affects people between 15 and 40 years of age. Common symptoms include abdominal cramps, bloody diarrhea, fever, weight loss and rectal bleeding. People with chronic, severe ulcerative colitis are at an increased risk of developing colorectal cancer. Crohn's disease causes chronic inflammation of the intestinal wall. While the cause of Crohn's is relatively unknown, it usually starts during the teenage years or early adulthood and is characterized by pain in the abdomen, diarrhea and weight loss.
Researchers: Patients with IBD More Likely to Be Diagnosed with Multiple Sclerosis
(Increased Risk of Demyelinating Diseases in Patients with Inflammatory Bowel Disease, Gupta, et al.)
A possible association between inflammatory bowel disease and multiple sclerosis (MS) has been suspected for decades, but previous studies have lacked the statistical power to confirm the relationship. A study published in this month's Gastroenterology is the first to confirm a nearly two-fold increased risk of multiple sclerosis in IBD patients. In addition to MS, researchers from the University of Pennsylvania found an association between IBD, optic neuritis and other demyelinating disorders.
Patients being treated with anti-TNF alpha therapies, such as Remicade and Humira, were previously thought to be the only ones with an increased risk of developing these neurological disorders. As a result, clinician and patient label warnings were added to this class of drugs in 2004. Study authors say the causal relationship between these drugs and demyelinating disorders has not clearly been established because of the small amount of data available from controlled clinical trials.
"While our study findings do not refute an association between anti-TNF alpha medications and these disorders, they point out that IBD patients appear to have an increased risk of multiple sclerosis even when they are not being treated with these medications," said James D. Lewis, MD, MSCE, study author from the University of Pennsylvania. "The development of neurologic symptoms in patients with IBD should prompt their physician to look for evidence of multiple sclerosis and other nervous system disorders."
This study identified more than 20,000 patients from the UK's General Practice Research Database diagnosed with Crohn's disease and ulcerative colitis between January 1988 and October 1997. Each study subject was then matched to four controls, making for an inclusion of about 80,000 control subjects without IBD. The odds of an IBD patient being diagnosed with multiple sclerosis, optic neuritis and other demyelinating disorders was found to be 1.7 times as high as those patients without IBD. If the association is confirmed by other studies, researchers believe findings may help to identify common genetic or environmental factors contributing to the development of Crohn's and ulcerative colitis.
People with Crohn's and Colitis at Greater Risk of Asthma, Researchers Say
(The Clustering of Other Chronic Inflammatory Diseases in IBD: A Population-Based Study, Bernstein, et al.)
In a similar study also published in this month's Gastroenterology, Canadian researchers looked at the relationship between IBD and common respiratory and neurological diseases. Results of this study suggest that the people with IBD have a significantly increased prevalence of asthma, bronchitis, arthritis and psoriasis. While some of these co-morbidities have been found previously, this study is the first to discover a significantly higher prevalence of asthma in IBD patients compared with non-IBD patients.
"People with IBD are 1.5 times as likely to have asthma as people in the general population," said Charles N. Bernstein, MD, lead study author from the University of Manitoba in Canada. "Airway diseases are the second most common chronic inflammatory disease assessed in patients with either Crohn's disease or ulcerative colitis."
Study data comes from the University of Manitoba IBD database, which included 8,072 people diagnosed with IBD over a 19-year period. Each of these people was matched randomly with 10 members of the general population by age, gender and geographic location. Ulcerative colitis patients were 50 to 70 percent more likely than the general population to have asthma, while Crohn's patients were about 30 to 40 percent more likely.
Overall, people with IBD had a significantly higher prevalence than the general population for the following disorders: asthma, bronchitis, arthritis, multiple sclerosis, chronic renal disease, psoriasis and pericarditis. This study is the largest population-based study to assess the co-morbidity of these important immune-based diseases. Differences were not only found between the two diseases, but also in gender and age. Females had a greater percentage of pulmonary co-morbidities than males and more old people had bronchitis.
"The findings from this study highlight an often overlooked association between intestinal disorders and the respiratory system," said Loftus. "Long-term consequences of untreated pulmonary involvement in IBD are substantial and physicians should at least follow-up respiratory complaints with pulmonary function tests."
More information on inflammatory bowel disease is available at www.gastro.org.
About the Studies
Increased Risk of Demyelinating Diseases in Patients with Inflammatory Bowel Disease, Gupta, et al.
Researchers from the University of Pennsylvania conducted a retrospective cross-sectional study and a cohort study to examine the association of IBD and multiple sclerosis, demyelination and optic neuritis to determine if these conditions are more common in IBD patients than non-IBD patients. The General Practice Research Database was used to gather the study population, which consisted of 20,173 patients from the United Kingdom with ulcerative colitis or Crohn's disease diagnoses between January 1988 and October 1997. Support for this research was provided by the National Institutes of Health.
The Clustering of Other Chronic Inflammatory Diseases in IBD: A Population-Based Study, Bernstein, et al.
Researchers at the University of Manitoba Inflammatory Bowel Disease Clinical and Research Centre in Canada conducted a population-based study to assess the number of additional chronic inflammatory conditions in patients with inflammatory bowel disease. The study population was derived from the University of Manitoba IBD database, which includes all people in the Manitoba health care system with a Crohn's disease and ulcerative colitis diagnosis. The study population consisted of 8,072 people with IBD diagnoses between April 1, 1984 and March 31, 2003. This research was partially supported by the Crohn's and Colitis Foundation of Canada and the Canadian Institutes of Health Research.
About the AGA
The American Gastroenterological Association (AGA) is dedicated to the mission of advancing the science and practice of gastroenterology. Founded in 1897, the AGA is the oldest medical-specialty society in the United States. The AGA's 14,500 members include physicians and scientists who research, diagnose and treat disorders of the gastrointestinal tract and liver. On a monthly basis, the AGA publishes two highly respected journals, Gastroenterology and Clinical Gastroenterology and Hepatology. The AGA's annual meeting is Digestive Disease Week®, which is held each May and is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.
About Gastroenterology
Gastroenterology, the official journal of the AGA, is the most prominent journal in the subspecialty and is in the top one percent of indexed medical journals internationally. The journal publishes clinical and basic studies of all aspects of the digestive system, including the liver and pancreas, as well as nutrition. The journal is abstracted and indexed in Biological Abstracts, CABS, Chemical Abstracts, Current Contents, Excerpta Medica, Index Medicus, Nutrition Abstracts and Science Citation Index. For more information, visit www.gastrojournal.org.
Journal
GASTROENTEROLOGY