Inflammatory Bowel Disease An Equal Opportunity Condition

Newswise — Medical College of Wisconsin researchers have collected and analyzed a huge volume of data on Wisconsin children with newly-diagnosed inflammatory bowel disease (IBD). Their epidemiological study, the first study of pediatric IBD in a large, defined, ethnically diverse North American population, paints a clearer picture of who this disease strikes and offers some clues about its cause. The study appears in the October issue of Journal of Pediatrics.

"Our data suggest that IBD is now an 'equal opportunity' condition equally afflicting all populations within our region," says lead researcher Subra Kugathasan, M.D., associate professor of pediatric gastroenterology who practices at Children's Hospital of Wisconsin a major teaching affiliate of the Medical College.

"The data suggest that among children in Wisconsin, new diagnoses of IBD are equally distributed throughout all populations, including minority groups previously felt to be at lower risk for the disease."

Inflammatory bowel disease is an umbrella term that covers ulcerative colitis (UC) and Crohn's disease (CD), both life-long, destructive, chronic inflammatory conditions of the gastrointestinal tract. UC affects the large intestine and rectum, CD (can also) affect the small intestine and any portion of the digestive tract. The diseases have long been linked to a combination of genetic and environmental factors. Previous studies have suggested that incidence of the diseases are more common in "westernized" countries, and seem to be on the increase.

Before the Medical College research there was no data on distribution of the disease in Wisconsin; neither CD nor UC are reportable diseases and there is no national registry to track IBD. "The goal was to determine the incidence of IBD in children in Wisconsin and to define the clinical characteristics of children who have it," says Dr. Kugathasan.

To accomplish this, the researchers gathered information from all the pediatric gastroenterologists in Wisconsin, plus those near Wisconsin borders in Illinois and Minnesota. They gathered data on all diagnosed children under age 18 who live in a Wisconsin ZIP code and entered it into a computer database. The data which does not identify individual patients included clinical presenting symptoms, family history of IBD, lab findings such as serological tests and radiological studies, and endoscopic evaluations. They also used data from the 2000 U.S. Census to determine county populations, ethnic composition and family size.

The researchers then ran standard statistical evaluations. They found several things:· Wisconsin's incidence of IBD in children is the highest in the world to date (however, there have been few studies of incidence in children).· Incidence of IBD was lowest at the lower ages and peaked at age 15.· The mean age of diagnosis for IBD was 12.5 years, however 20 percent of cases were diagnosed under age 10.· CD occurred twice as often as UC in this population.· CD occurred at a significantly higher rate in males.· Previous studies have shown a higher incidence of IBD in urban populations; this study contradicted that - incidence was similar in urban or rural areas.· Incidence was similar in all racial/ethnic groups.· Only 11 percent of newly diagnosed children had a first or second degree family member with IBD.

"Our study, demonstrating a high incidence of IBD in Wisconsin children, suggests that environmental factors are dominant in the changing pattern of this disease since the genetic make-up of human populations does not shift over short periods of time," says Dr. Kugathasan. "It suggests that IBD continues to evolve, as pediatric IBD now afflicts all races as well as rural and urban populations with similar frequency."

Besides Dr. Kugathasan, the research team from Wisconsin was made up of Robert Judd, Raymond Hoffmann, Ph.D., Janice Heikenen, Gregorz Telega, M.D., Farhat Khan M.D., Sally Weisdorf-SchindeleM.D, William San Pabo Jr.M.D., Jean Perrault, M.D., Roger Park M.D., Michael Yaffe M.D., Christopher Brown M.D., Maria Rivera-Bennett M.D., Issam Halabi M.D., Alfonso Martinez, M.D., Ellen Blank, M.D., Steven Werlin, M.D., Colin Rudolph, M.D., and David Binion, M.D.

Having identified a well characterized pediatric IBD population in a geographically defined area, the researchers are geared to study the natural history of Crohn's disease and ulcerative colitis in children in a prospective manner. Since, this population based cohort is not subjected to referral bias inherent to most of the previously published studies, this future research findings will also define the populations at risk for complications, and identify the sub-populations whose disease course may be severe. Further, following the identification of the first Crohn's disease associated gene NOD2, the lead researcher Dr Kugathasan also in the process of studying the effect of this NOD2 gene in this IBD population.