Association Between Inflammatory Bowel Disease and Venous Leg Ulcers: Insight From Mendelian Randomization Analyses.

Area of Science:

• Genetics
• Gastroenterology
• Vascular Medicine

Background:

• Observational studies suggest a link between inflammatory bowel disease (IBD) and venous leg ulcers (VLU).
• The underlying causal relationship remains unclear.
• Genetic factors may influence both conditions.

Purpose of the Study:

• To investigate the potential causal relationship between IBD and VLU using Mendelian randomization (MR).
• To determine if shared genetic factors contribute to the observed association between IBD and VLU.

Main Methods:

• Utilized independent genetic variants associated with IBD and VLU from genome-wide association studies (GWAS).
• Employed various MR analysis methods including inverse-variance weighted (IVW), weighted median, MR Egger, simple mode, and weighted mode.
• Focused on individuals of European descent.

Main Results:

• Mendelian randomization analysis showed no statistically significant causal association between genetically predicted IBD and VLU (IVW OR 0.95, p=0.23).
• Subgroup analyses for ulcerative colitis (UC) and Crohn's disease (CD) also revealed no significant association with VLU.
• Sensitivity analyses using different MR methods corroborated the primary finding.

Conclusions:

• This MR study found no genetic evidence supporting a causal link between IBD and VLU.
• The observed clinical association between IBD and VLU is unlikely to be driven by shared genetic factors.
• These genetic insights aid in refining clinical assessments of VLU in IBD patients.