Study of small intestinal bacterial overgrowth in North Indian patients with irritable bowel syndrome: a case control study.

BACKGROUND: Approximately 20% of the general population has irritable bowel syndrome. Despite this high prevalence, the cause of irritable bowel syndrome is unknown. There is no data available concerning the prevalence of small intestinal bacterial overgrowth in North Indian patients with irritable bowel syndrome. AIM: This study evaluated the prevalence of small intestinal bacterial overgrowth in patients with irritable bowel syndrome compared with healthy controls. METHODS: This study included 225 consecutive patients of irritable bowel syndrome between the ages 20 and 65 years attending the gastroenterology clinics. Diagnosis of irritable bowel syndrome was made according to the Rome II criteria. Small intestinal bacterial overgrowth was estimated by using the non-invasive glucose hydrogen breath test. RESULTS: Of 225 patients of irritable bowel syndrome, 160 (71.1%) were male and 65 (28.9%) were female. Of 100 controls, 65 (65%) were male and 35 (35%) female. The prevalence of small intestinal bacterial overgrowth was 25 of 225 (11.1%) patients with irritable bowel syndrome and 1 of 100 (1%) in apparently healthy controls. This difference was statistically significant. The prevalence of small intestinal bacterial overgrowth in male and female patients was not significantly different. CONCLUSION: This study indicates that the prevalence of small intestinal bacterial overgrowth in irritable bowel syndrome patients from North India is approximately 11.1%, which is lower than the reported prevalence.