Association between Statin Use and Inflammatory Bowel Diseases: Results from a Swedish, Nationwide, Population-based Case-control Study

Background: In addition to their potent lipid-lowering action, statins may modulate inflammation. However, data on statin use and the risk of inflammatory bowel diseases [IBD] have been inconsistent. Methods: We searched the Nationwide Swedish Patient Register [inpatient and non-primary outpatient care] to identify adults diagnosed with Crohn's disease [CD, n=7637] or ulcerative colitis [UC, n=15 652] from 2006 to 2014. Each case was matched to 10 general population controls [n=232 890]. Data on dispensed statin prescriptions were extracted from the Prescribed Drug Register. Conditional logistic regression models estimated odds ratios [ORs] for risk of IBD according to statin exposure while controlling for potential confounders, including indications for statin therapy. Results: In multivariable adjusted models, compared with no statin use, any statin use was associated with a lower risk of CD (OR=0.71; 95% confidence interval [CI], 0.63-0.79), but not UC [OR=1.03; 95% CI, 0.96-1.11]. The lowest OR for CD was seen for current statin use [OR=0.67; 95% CI, 0.60-0.75]. For CD, the lowest category of cumulative statin dose [31-325 defined daily dose, DDD] was associated with an OR of 0.73 [95% CI, 0.61-0.88] and the highest category [>1500 DDD] with an OR of 0.66 [95% CI, 0.55-0.80], ptrend=0.10. For UC, the lowest and highest dose categories yielded ORs of 1.12 [95% CI, 1.00-1.25] and 0.99 [95% CI, 0.88-1.13], respectively, ptrend = 0.13. Conclusions: Statin use was associated with a lower risk of CD, but not of UC. The association with CD risk appeared strongest for current statin use. Our findings suggest that statin use may influence the development of CD.