ABSTRACT
Objective @#To examine the causal relationship between ulcerative colitis (UC) and pancreatitis, to provide basis for early screening of pancreatitis among UC patients.@*Methods@#Genomic data of UC were obtained from 47 745 European individuals pooled by the International Inflammatory Bowel Disease Genetics Consortium, including 156 116 single nucleotide polymorphism (SNP), and genomic data of pancreatitis were obtained from 198 166 European individuals pooled from FinnGen, including 16 380 428 SNPs. Mendelian randomization (MR) analysis was performed using the inverse variance weighted (IVW) method with 72 UC-associated SNPs as instrumental variables and pancreatitis as the study outcome. The heterogeneity was assessed using Cochran Q test, the horizontal pleiotropy was assessed using MR-Egger regression, MR-PRESSO was performed with the exclusion of outliers, and effect of individual SNP on the results was tested with the leave-one-out method. @*Results@#MR analysis results showed that patients with genetically predicted UC had an increased risk of pancreatitis relative to those without UC (OR=1.076, 95%CI: 1.019-1.136, P<0.05). Cochran Q test showed no heterogeneity (P>0.05), and MR-Egger regression did not reveal horizontal pleiotropy of instrumental variables (P>0.05). The MR analysis results were robust after removing SNP one by one.@*Conclusions@#Genetically predicted UC is associated with an increased risk of pancreatitis. The screening for pancreatitis risk should be enhanced in patients with UC.