Irritable bowel syndrome, gastro-oesophageal reflux, and bronchial hyper-responsiveness in the general population.

BACKGROUND Associations have been shown between irritable bowel syndrome (IBS) and gastro-oesophageal reflux, between gastro-oesophageal reflux and asthma, and more recently between IBS and bronchial hyper-responsiveness (BHR). AIMS To explore the inter-relations between these conditions. SUBJECTS A randomly selected community sample of 4432 adults. METHODS A validated postal symptom questionnaire investigating the associations between IBS, gastro-oesophageal reflux symptoms, and symptomatic BHR. RESULTS 3169 questionnaires (71.7% response) returned by 1451 men and 1718 women were analysed. One year prevalences, in men and women respectively, of IBS were 10.5% and 22.9%, of dyspepsia 26.3% and 25. 25%, of gastro-oesophageal reflux symptoms 29.4% and 28.2%, of BHR 13.2% and 14.6%, and of chronic bronchitis 8.3% and 4.9%. Logistic regression showed independent associations between IBS and BHR, gastro-oesophageal reflux symptoms, and dyspepsia. There was no significant independent association between IBS and chronic bronchitis. In men and women the odds ratio with 95% confidence interval (CI) for IBS and gastro-oesophageal reflux symptoms was 2.6 (2.1-3.1; p<0.001) and for IBS and BHR 2.1 (1.7-2.7; p<0.001). These associations held on stratifying for sex and consultation behaviour. IBS, gastro-oesophageal reflux symptoms, and bronchial hyper-responsiveness occurred more frequently together than expected, 2.5% (95% CI 2.41-2.57) of the sample having all three conditions compared with an expected prevalence of 0.7% (95% CI 0.66-0.71). The conditions were independently associated with each other. CONCLUSIONS These observations may indicate the presence of an underlying disorder producing symptoms in gastrointestinal and respiratory systems.