DDW 2009: Risk for IBD Nearly Tripled After Campylobacter or Salmonella Infection

Martha Kerr

June 04, 2009

June 4, 2009 (Chicago, Illinois) — A population-based cohort study conducted in Denmark showed a nearly 3-fold increased incidence of inflammatory bowel disease (IBD) after infection with Campylobacter or Salmonella, Danish researchers announced this week at Digestive Disease Week 2009.

"The increased risk in exposed subjects was observed throughout the 15-year observation period," reported Henrik Nielsen, MD, professor of infectious diseases at Aalborg Hospital in Denmark.

"Genetic and environmental factors, including infections, are believed to be involved in the pathogenesis of IBD," Dr. Nielsen said.

The Danish researchers compared risk for IBD in 2 groups from North Jutland and Aarhus counties in Denmark between 1991 and 2003: 13,149 patients with laboratory-confirmed Salmonella (6,464 cases) or Campylobacter (6,685 cases) gastroenteritis; and 26,218 age- and sex-matched unexposed controls. Patients with a history of IBD were excluded from the analysis.

Individuals were followed for up to 15 years (mean, 7.5 years).

A first-time diagnosis of IBD was reported in 107 exposed individuals (1.2%) and 74 unexposed individuals (0.5%) during follow-up.

Dr. Nielsen's team calculated a hazard rate ratio for IBD of 2.9 (95% confidence interval [CI], 2.1 - 3.9) over 15 years of follow-up. There was a hazard rate ratio of 1.9 (95% CI, 1.3 - 2.6) "if the first year after Salmonella/Campylobacter infection was excluded."

"The increased risk was similar for Salmonella and Campylobacter and independent of the age and gender of the patient," Dr. Nielsen told meeting attendees.

The increase in risk for a first-time diagnosis of Crohn's disease (47 cases) and ulcerative colitis (134 cases) was not significantly different.

"There is no clear picture of causality between these food-borne illnesses and IBD," Dr. Nielsen said.

"If we believe these to be causative organisms, then these patients are at risk, and we need to monitor gastrointestinal symptoms closely for signs of IBD after resolution of the initial infection," Sunanda V. Kane, MD, professor of medicine, Department of Gastroenterology and Hepatology at the Mayo Clinic in Rochester, Minnesota, and panel moderator, told Medscape Gastroenterology.

"It is important since the incidence of these infections is rapidly increasing."

"It is possible that these patients are predisposed to IBD in other ways, for other reasons, such as smoking, the environment, medications, and so on. I believe that, if these infections are associated with IBD, they are not causative, but they may be triggers. The 2 events could be happening in parallel. We need to look at other populations," Dr. Kane observed.

The study was not commercially funded. Dr. Nielsen and Dr. Kane have disclosed no relevant financial relationships.

Digestive Disease Week (DDW) 2009: Abstract 80. Presented June 1, 2009.


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