Asthma frequently occurs with Crohn’s disease, ulcerative colitis
Asthma appears to be associated with inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis, a recent study suggests.
Researchers performed a systematic review of studies evaluating observational epidemiologic studies (case-control, cohort or cross-sectional) that either compared the rate of asthma in patients with and without IBD or the rate of IBD in patients with and without asthma. A total of 18 studies were included in the meta-analysis.
Pooled random effects models showed asthma to be associated with both Crohn’s disease (relative risk [RR], 1.30; 95 percent CI, 1.16–1.47; I2, 88 percent) and ulcerative colitis (RR, 1.34; 1.24–1.44; I2, 93 percent).
The study design, data source and study location accounted for the significant between-study heterogeneity across studies in Crohn’s disease but not ulcerative colitis.
Researchers noted that the association between asthma and Crohn’s disease was consistent irrespective of the relative timing of the diagnoses of the two diseases (ie, asthma preceding Crohn’s disease or Crohn’s disease preceding asthma). On the other hand, while the risk of asthma was elevated in patients with existing ulcerative colitis, the risk of ulcerative colitis did not appear to be heightened in patients with existing asthma.
In light of the findings, it is unclear whether one disease induces a predisposition to the other or the co-occurrence of these diseases arises due to the commonalities in the physiology of the gut and the lung, as well as to shared genetic and environmental risk factors, researchers pointed out. Further investigations are needed to address these issues.