Background: Individual studies suggest that post-infectious irritable bowel syndrome is common, but symptoms gradually improve.

Aim: To review evidence for an association between intestinal infection and development of irritable bowel syndrome, assess the prognosis of post-infectious irritable bowel syndrome and explore factors that increase the risk.

Methods: MEDLINE (1966-2007) and EMBASE (1980-2007) databases were searched to identify the studies of post-infectious irritable bowel syndrome epidemiology. Data were extracted by two independent reviewers. Pooled odds ratios (POR) and corresponding 95% CI for incidence of irritable bowel syndrome were estimated among the exposed and unexposed groups.

Results: Eighteen of 26 studies identified were eligible for inclusion. Intestinal infection was associated with increased odds of developing irritable bowel syndrome at study end (POR = 5.86; 95% CI: 3.60-9.54). In subgroup analysis, the odds of developing irritable bowel syndrome was increased at 3 months (POR = 7.58; 95% CI: 4.27-13.45), 6 months (POR = 5.18; 95% CI: 3.24-8.26), 12 months (POR = 6.37; 95% CI: 2.63-15.40) and 24-36 months (POR = 3.85; 95% CI: 2.95-5.02). Among all studies (controlled and uncontrolled), the pooled incidence of irritable bowel syndrome at study conclusion was 10% (95% CI: 9.4-85.6). Subjects with post-infectious irritable bowel syndrome were younger and more anxious and depressed than those without post-infectious irritable bowel syndrome.

Conclusion: The odds of developing irritable bowel syndrome are increased sixfold after acute gastrointestinal infection. Young age, prolonged fever, anxiety and depression are risk factors for post-infectious irritable bowel syndrome.