Gut 59:605-611 doi:10.1136/gut.2009.202234
  • Irritable bowel syndrome

Eight year prognosis of postinfectious irritable bowel syndrome following waterborne bacterial dysentery

  1. Walkerton Health Study Investigators
  1. 1Department of Medicine (Division of Gastroenterology) and Farncombe Family Digestive Health Research Institute,McMaster University, Hamilton, Ontario, Canada
  2. 2Department of Medicine (Division of Nephrology), University of Western Ontario, London, Ontario, Canada
  1. Correspondence to Dr John K Marshall, Division of Gastroenterology (2F59), McMaster University Medical Centre, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada; marshllj{at}
  1. Contributors Study concept and design (JKM, MT, AXG, WFC, SMC); acquisition of data (JKM, MT, AXG, WFC); analysis and interpretation of data (JKM, MT, AXG, PM, SMC); drafting of the manuscript (JKM, MT); critical revision of the manuscript for important intellectual content (JKM, MT, AXG, WFC, PM, SMC); statistical analysis (MT); obtaining funding (JKM, MT, PM, SMC); study supervision (JKM, SMC).

  • Received 2 November 2009
  • Accepted 24 December 2009


Background Although postinfectious irritable bowel syndrome (PI-IBS) is a well-recognised complication of acute gastroenteritis, its prognosis remains poorly defined. The natural history of PI-IBS was assessed among participants in the Walkerton Health Study (WHS), which has followed the long-term effects of a large outbreak of acute gastroenteritis related to municipal water contamination in May 2000.

Methods WHS participants were invited to return for annual assessment at a research clinic. Adult residents of Walkerton at the time of the outbreak who enrolled in 2002/2003 and returned for assessment in 2008 were eligible for a PI-IBS study cohort if they had no prior history of IBS or inflammatory bowel disease. A modified Bowel Disease Questionnaire was used to diagnose IBS by Rome I criteria and to identify IBS subtypes.

Results Of 4561 WHS participants, 2451 returned for their 8 year assessment and 1166 were eligible for the PI-IBS study cohort (688 females, mean age 46.2 years). The prevalence of IBS among 742 eligible subjects who suffered acute gastroenteritis during the outbreak declined from 28.3% after 2–3 years to 15.4% after 8 years, but remained significantly increased compared with controls who did not have acute gastroenteritis (OR 3.12; 95% CI 1.99 to 5.04). Independent risk factors for PI-IBS at 8 years included female gender, younger age, prior anxiety/depression, and fever or weight loss during the acute enteric illness. IBS subtypes were not stable over time.

Conclusions Acute gastroenteritis can trigger IBS symptoms that persist for at least 8 years. Characteristics of the host and the acute enteric illness can predict the long-term risk of PI-IBS.


  • Walkerton Health Study Investigators: William Clark, Stephen M. Collins, Amit Garg, R. Brian Haynes, John Howard, Jennifer MacNab, Jeff Mahon, John K. Marshall, Douglas Matsell, Louise Moist, Janet Pope, Joel Ray, Patricia Rosas-Arellano, Marina Salvadori, Rita Suri.

  • Funding Ontario Ministry of Health and Long-Term Care and the Crohn's and Colitis Foundation of Canada (CCFC).

  • Competing interests None.

  • Ethics approval The study protocol received full approval from both the Hamilton Health Sciences/McMaster University Research Ethics Board (Hamilton, Ontario) and the University of Western Ontario's Office of Research Ethics (London, Ontario).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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