Abstract:

Aim: Irritable bowel syndrome (IBS) and lactose intolerance (LI) may co-exist and readily cause diagnostic confusion due to similar symptomatology. This study aims to examine the frequency of LI in healthy controls and in participants diagnosed with IBS based on Roma III criteria, as an effort to investigate the association between IBS and LI. Materials and Methods: The patient population consisted of individuals between 18 and 80 years of age who attended between June-December 2013. Patients diagnosed with IBS based on Roma III criteria comprised the IBS group, and subtypes of IBS. Control group was healthy volunteers over 18 years of age with no IBS-like symptoms. All participants ingested 25 g of lactose dissolved in 250 ml of water within 5 minutes after 8 hours of fasting, in order to evaluate the LI via hydrogen breath test (0, 15, 30, 60, 90, and 120 minutes). Results: Of the total 200 participants, 100 (50%) were in the IBS group and 100 (50.0%) were in the control group. Of the total 70 patients (35.0%) with LI, 47 (47.0%) were in the IBS group and 23 (23.0%) were in the control group (p=0.001). Symptoms related to IBS were more common in participants with LI in both groups (p=0.001, p=0.001 respectively). Conclusion: A significantly increased frequency of LI was found among IBS patients than in controls. In addition, symptoms associated with lactose intake occurred at a higher frequency in IBS patient, although the difference was insignificant.

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