title: Postinfectious irritable bowel syndrome after a food-borne outbreak of acute gastroenteritis attributed to a viral pathogen.
abstract: OBJECTIVE
  A large outbreak of acute gastroenteritis at the annual meeting of the Canadian Society of Gastroenterology Nurses and Associates (CSGNA) was attributed to food-borne norovirus. A prospective study was undertaken to determine the incidence and natural history of postinfectious irritable bowel syndrome (PI-IBS).
  
  
  METHODS
  Questionnaires addressing demographics, medical history, acute illness, prior bowel function, and current symptoms were mailed to all delegates within 1 month of the outbreak. Follow-up questionnaires were mailed at 3, 6, 12, and 24 months. The prevalence of new Rome I IBS among participants with and without acute enteric illness during the outbreak was calculated for each time point. Risk factors were assessed by multiple logistic regression.
  
  
  RESULTS
  Baseline surveys were returned by 139 of 197 delegates (70.6%; mean age, 48 +/- 6 years; 95.0% female), of whom 135 (97.1%), 133 (95.7%), 128 (92.1%), and 116 (83.4%) returned the 3-, 6-, 12-, and 24-month surveys, respectively. One hundred seven respondents (76.9%) reported an acute enteric illness during the outbreak. Eighteen subjects reported premorbid IBS. Among the remainder, 21 of 89 who experienced gastroenteritis (23.6%) reported symptoms consistent with PI-IBS at 3 months versus 1 of 29 (3.4%) who remained well (odds ratio, 6.9; 95% confidence interval, 1.0-48.7; P = .014). At 6, 12, and 24 months, the prevalence of IBS was similar among exposed versus nonexposed individuals. In multiple logistic regression, vomiting during the acute illness independently predicted risk of PI-IBS at 3 months (odds ratio, 10.5; 95% confidence interval, 1.3-85.5; P = .028).
  
  
  CONCLUSIONS
  PI-IBS is common after presumptive viral gastroenteritis but might be more transient than after bacterial dysentery.
authors.affiliation: Division of Gastroenterology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada. marshllj@mcmaster.ca
authors.forename: John K
authors.initials: JK
authors.lastname: Marshall
authors.forename: Marroon
authors.initials: M
authors.lastname: Thabane
authors.forename: Mark R
authors.initials: MR
authors.lastname: Borgaonkar
authors.forename: Cindy
authors.initials: C
authors.lastname: James
mesh_terms: D000208:Acute Disease; D000328:Adult; D017677:Age Distribution; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks; D005260:Female; D005517:Foodborne Diseases / Q000453:epidemiology / Q000821:virology*; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D011336:Probability; D011379:Prognosis; D012720:Severity of Illness Index; D017678:Sex Distribution; D011795:Surveys and Questionnaires