Prevalence of small intestinal bacterial overgrowth in children with irritable bowel syndrome: a case-control study

J Pediatr. 2009 Sep;155(3):416-20. doi: 10.1016/j.jpeds.2009.03.033. Epub 2009 Jun 16.


Objective: To assess the prevalence of small intestinal bacterial overgrowth (SIBO) in children affected by irritable bowel syndrome (IBS).

Study design: Consecutive children affected by IBS according to Rome II criteria (n = 43) were enrolled at the Gemelli Hospital, Catholic University of Rome. The control population (n = 56) consisted of healthy subjects without IBS symptoms, similar to patients for age, sex, and social background. All subjects underwent lactulose/methane breath test (LBT) to assess small intestinal bacterial overgrowth.

Results: The prevalence of abnormal LBT result was significantly higher in patients with IBS (65%, 28/43) with respect to control subjects (7%, 4/56; OR 3.9, 95% CI 7.3-80.1, P < .00001). Patients with abnormal LBT showed a trend toward a worse visual analog scale score with respect to children with IBS without SIBO, but a significant statistical difference was observed only for bloating.

Conclusions: Results from this study suggest a significant epidemiologic association between SIBO and IBS in childhood. Placebo-controlled interventional studies with antibiotics used to treat bacterial overgrowth are warranted to clarify the real impact of the disease on IBS symptoms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Bacterial Infections / diagnosis
  • Bacterial Infections / epidemiology*
  • Bacterial Infections / metabolism
  • Bacterial Infections / microbiology*
  • Breath Tests / methods
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Comorbidity
  • Female
  • Humans
  • Intestine, Small / metabolism
  • Intestine, Small / microbiology*
  • Irritable Bowel Syndrome / diagnosis
  • Irritable Bowel Syndrome / epidemiology*
  • Irritable Bowel Syndrome / microbiology*
  • Lactulose / metabolism
  • Male
  • Methane / metabolism
  • Pain Measurement
  • Prevalence
  • Rome / epidemiology
  • Severity of Illness Index


  • Lactulose
  • Methane