Causal association between inflammatory bowel disease and acute pancreatitis: a two-sample bidirectional mendelian...

Area of Science:

• Gastroenterology
• Genetics
• Epidemiology

Background:

• Acute pancreatitis (AP) is recognized as an extraintestinal manifestation of inflammatory bowel disease (IBD).
• Observational studies suggest an elevated risk of AP in IBD patients, but causal links remain unclear.
• Limitations in observational research necessitate exploring the directionality and causality between IBD subtypes and AP.

Purpose of the Study:

• To investigate the potential causal relationship between inflammatory bowel disease (IBD) and acute pancreatitis (AP) risk.
• To determine the directionality of the association between IBD subtypes (Crohn's disease and ulcerative colitis) and AP.
• To utilize Mendelian Randomization (MR) to overcome limitations of observational studies in establishing causality.

Main Methods:

• A two-sample bidirectional Mendelian Randomization (MR) study design was employed.
• Genetic variants associated with IBD and AP were selected as instrumental variables from large-scale genetic databases.
• Primary analysis used the inverse-variance weighted (IVW) method, with sensitivity analyses including MR-Egger, MR-Presso, and Leave-one-out methods to assess robustness.

Main Results:

• Inflammatory bowel disease (IBD) and specifically ulcerative colitis (UC) demonstrated a significant causal association with an increased risk of acute pancreatitis (AP).
• Crohn's disease (CD) did not show a significant causal association with the risk of AP.
• A suggestive inverse association was observed between AP and the risk of CD, but no causal link was found between AP and the risk of IBD or UC.

Conclusions:

• This study provides robust genetic evidence supporting a causal role of IBD, particularly UC, in the development of AP.
• The findings suggest that CD does not exert a causal influence on the risk of developing AP.
• The bidirectional MR approach clarifies the etiological link, indicating IBD influences AP risk, not vice versa.