Background: An association between Irritable Bowel Syndrome (IBS) and bronchial hyper-responsiveness has been suggested. Only a few studies have specifically studied the association between IBS and asthma.
Aim: To estimate the incidence rate of IBS among asthma patients and to compare it with the general population. We also examined the association between use of asthma drugs, specifically corticosteroids, and IBS.
Methods: Population-based cohort study using the General Practice Research Database (GPRD) in the UK. The cohort comprised a random sample of 50,000 asthma patients aged 10-79 years and a similar number of sex- and age-matched individuals free of asthma and identified from the source population. A nested case-control analysis was performed within the asthma cohort to examine the association between asthma drugs and IBS.
Results: The incidence rate of IBS in the asthma cohort was 2.5 per 1000 persons-years and 2.0 in the general population. The relative risk (RR) was 1.3 (95% CI 1.1-1.5). A medical history of neurotic and psychologic disorders, pain-related diseases and gastroenteritis were all associated with the occurrence of IBS. In the asthma cohort, current users of oral steroids presented a RR of 0.5 (95% CI 0.2-1.2) for developing IBS. The risk estimate was similar in short- and long-term users of steroids.
Conclusions: We found a slightly increased risk of IBS in asthma patients compared to the general population and that the risk of IBS was reduced by use of oral steroids in asthma patients. Additional studies in the general population are necessary in order to confirm whether use of corticosteroids irrespective of asthma has a protective effect on the risk of IBS.