Prevalence of Small Intestinal Bacterial Overgrowth in Children with Irritable Bowel Syndrome: A Case-Control Study

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 11 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. (J Pediatr 2009,155:416-20).