# Exploring the Causal Relationship Between Inflammatory Bowel Disease and Bell's Palsy Based on Inflammatory Proteins: A Mendelian Randomization Study

## TL;DR

This study suggests that inflammatory bowel disease may increase the risk of Bell's palsy and identifies specific inflammatory proteins that could be shared between the two conditions.

## Contribution

The study identifies genetic evidence of a causal link between IBD and Bell's palsy and highlights potential shared inflammatory pathways.

## Key findings

- IBD is significantly associated with an increased risk of Bell's palsy.
- CXCL5 and IL_17C are potential shared inflammatory proteins between IBD and Bell's palsy.
- SLAMF1 acts as a protective factor for Bell's palsy but a risk factor for IBD.

## Abstract

The relationship between inflammatory bowel disease (IBD) and Bell's palsy remains unsubstantiated. This study aims to investigate the causal relationship between IBD and Bell's palsy.

Using the two‐sample Mendelian randomization (MR) method to explore the relationship between IBD and Bell's palsy. We applied Bell's palsy summary statistics from GWAS statistics for 91 inflammatory proteins and FinnGen R10 and IBD summary statistics from the International Inflammatory Bowel Disease Genetics Consortium.

The two‐sample MR study indicates a significant positive association between IBD and Bell's palsy (OR: 1.13, 95% CI [1.03–1.23], p = 0.0065) and between Crohn's disease and Bell's palsy (OR: 1.10, 95% CI [1.02–1.18], p = 0.0088). After applying Bonferroni correction, IBD remained significantly correlated with Bell's palsy. Subsequently, the causal relationship between circulating inflammatory proteins in Bell's palsy and inflammatory bowel disease samples was reevaluated. The results of the MR study on inflammatory proteins in these two diseases suggest that the C‐X‐C Motif Chemokine Ligand 5 (CXCL5) is a potential protective factor and interleukin_17C (IL_17C) is a risk factor for these two diseases. Conversely, Signaling Lymphocytic Activation Molecule Family Member 1 (SLAMF1) is a protective factor for Bell's palsy and a risk factor for inflammatory bowel disease.

The findings indicate that IBD may be a risk factor for Bell's palsy at the genetic level. CXCL5, IL_17C, and SLAMF1 are possible co‐acting pathways between Bell's palsy and inflammatory bowel disease. These findings may provide new targets for the treatment of both diseases.

Inflammatory bowel diseasemay be a risk factor for Bell's palsy at the genetic level. CXCL5, IL_17C, and SLAMF1 are possible co‐acting pathways between Bell's palsy and inflammatory bowel disease.