The causality between chronic rhinosinusitis and inflammatory bowel disease: A bidirectional 2-sample Mendelian...

Area of Science:

• Gastroenterology and Otolaryngology
• Genetic Epidemiology

Background:

• Observational studies suggest a link between chronic rhinosinusitis (CRS) and inflammatory bowel disease (IBD).
• Causality between CRS and IBD remains uncertain.
• Mendelian randomization (MR) is a robust method for inferring causality from genetic data.

Purpose of the Study:

• To investigate the potential bidirectional causal relationship between CRS and IBD using a 2-sample MR analysis.
• To assess causality between CRS and IBD subtypes, including Crohn's disease and ulcerative colitis.

Main Methods:

• Utilized a bidirectional 2-sample Mendelian randomization (MR) approach.
• Employed genetic variants associated with CRS and IBD from the IEU Open GWAS database.
• Applied inverse-variance weighted, weighted median, and MR-Egger methods for primary analysis.
• Conducted sensitivity analyses including Cochran's Q test and MR-Egger intercept to assess pleiotropy and robustness.

Main Results:

• MR analysis indicated that CRS causally increases the risk of IBD (OR = 1.108, P = 0.032).
• Reverse MR analysis suggested that IBD causally increases the risk of CRS (OR = 1.035, P = 0.043).
• No significant causal associations were detected between CRS and specific IBD subtypes (Crohn's disease, ulcerative colitis).
• Sensitivity analyses confirmed the robustness of the findings and found no evidence of pleiotropy.

Conclusions:

• This MR study provides evidence for a bidirectional causal relationship between chronic rhinosinusitis and inflammatory bowel disease.
• The causal link was not significant for individual IBD subtypes.
• Further research is warranted to explore the underlying biological mechanisms connecting CRS and IBD.