Bronchial Hyperresponsiveness in Irritable Bowel Syndrome

Extraintestinal symptoms are often found in patients with irritable bowel syndrome (IBS). Recent studies suggest that IBS is associated with bronchial hyperresponsiveness. But it is still arguable that the bronchial hyperresponsiveness is associated with IBS patients. The purpose of this study is to investigate the possible relationship between IBS and bronchial hyperresponsiveness. Forty-two patients with IBS and 42 control subjects were included in this study. All patients underwent pulmonary function, methacholine challenge, and skin prick tests. There was no statistical difference between the two groups with respect to percentage of all pulmonary function test parameters, including FEV₁%, FCV%, FVC/FEV₁, and FEF_{25 − 75}%. Only two persons in the alternating-type IBS patient group and one person in the control group tested positive in the methacholine provocation test. But all PC₂₀ values were above 16 mg/ml. These results do not demonstrate a relationship between bronchial hyperresponsiveness and IBS. However, a relationship might exist in a subpopulation of IBS patients.