Risk of Prevalent Asthma among Children Affected by Inflammatory Bowel Disease: A Population-Based Birth Cohort Study

Literature on the risk of asthma among children with inflammatory bowel disease (IBD) is limited and has reported discording results. To the best of our knowledge, no previous study has evaluated the association between asthma and childhood onset IBD, focusing on pediatric IBD with onset between 10 and 17 years, early-onset IBD (EO-IBD) between 0 and 9 years, and very early-onset IBD (VEO-IBD) between 0 and 5 years, all conditions characterized by different clinical progressions. A nested matched case-control design on a longitudinal cohort of 213,515 newborns was adopted. Conditional binomial regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) of asthma among children with IBD compared with controls. We found 162 children with IBD and 1620 controls. Overall, childhood onset IBD was associated with increased risks of being affected by asthma (OR: 1.49 95% CI 1.05-2.12), although a significant risk was only present among males (OR: 1.60 95% CI 1.02-2.51). Children with Crohn's disease and ulcerative colitis had similarly increased risks, although they failed to attain statistical significance. Risks of asthma based on age at IBD onset were inversely related to age, with the lowest non-significant risks for pediatric IBD and EO-IBD, while children affected by VEO-IBD had the highest risk of asthma (OR: 2.75 95% CI 1.26-6.02). Our study suggests the presence of a higher prevalence of asthma among both male children with IBD and children with VEO-IBD. It could be advisable to pay greater attention to possible respiratory symptoms among these categories at higher risk.