Association between the use of lipid-lowering drugs and the risk of inflammatory bowel disease

Background: Observational studies have suggested an association between lipid-lowering drugs and inflammatory bowel disease (IBD) risk. This study aimed to assess the causal influence of lipid-lowering agents on IBD risk using Mendelian randomization analysis. Method: In a population of 173,082 individuals of European ancestry, 55 single-nucleotide polymorphisms were identified as instrumental variables for 6 lipid-lowering drug targets (HMGCR, NPC1LC, PCSK9, LDLR, CETP and APOB). Summary statistics for the genome-wide association study of IBD, ulcerative colitis (UC) and Crohn's disease (CD) were obtained from the FinnGen consortium, Program in Complex Trait Genomics and UK Biobank. Inverse-variance weighted was employed as the primary MR method, and odds ratios (ORs) with 95% confidence intervals were reported as the results. Sensitivity analyses using conventional MR methods were conducted to assess result robustness. Results: Gene-proxied inhibition of Niemann-Pick C1-like 1 (NPC1L1) was associated with an increased IBD risk (OR [95% CI]: 2.31 [1.38, 3.85]; p = .001), particularly in UC (OR [95% CI]: 2.40 [1.21, 4.74], p = .012), but not in CD. This finding was replicated in the validation cohort. Additionally, gene-proxied inhibition of low-density lipoprotein receptor was associated with reduced IBD (OR [95% CI]:.72 [.60,.87], p < .001) and UC risk (OR [95% CI]:.74 [.59,.92], p = .006), although this result was not replicated in the validation cohort. Other drug targets did not show significant associations with IBD, UC or CD risk. Conclusion: Inhibition of the lipid-lowering drug-target NPC1L1 leads to an increased IBD risk, mainly in the UC population.