Association Between Inflammatory Bowel Disease and Dementia: A Retrospective Cohort Study

Background: The critical role of inflammatory processes in the pathogenesis of dementia has recently been established. Objective: The aim of this study was to investigate the association between inflammatory bowel disease (IBD) and dementia risk in patients followed in general practices in Germany. Methods: This study included patients aged over 60 with an initial diagnosis of IBD (Crohn's Disease (CD), ulcerative colitis (UC)) who were followed in 1,159 German general practices between January 1995 and December 2014. IBD patients were matched to healthy patients using propensity scores based on age, gender, index year, insurance type and comorbidities. Kaplan-Meier curves were used to study the development of dementia in patients with or without IBD within up to 15 years of the index date. Cox proportional hazard regression models were used to estimate the relationship between IBD and dementia. Results: The study included 3,850 patients with and 3,850 patients without IBD and revealed a higher cumulative incidence of dementia in IBD patients than in non-IBD patients after the follow-up period. The cumulative incidence of dementia differed within IBD subtypes; it was significantly higher in UC patients than in CD patients. Cox proportional hazard models showed that IBD is associated with a 1.22-fold increase in the risk (95% CI: 1,07-1,39) of developing dementia. UC patients had a 1.25-fold higher risk of developing dementia (95% CI: 1.07-1.46). CD is not significantly associated with an increased risk of dementia (HR: 1.17, 95% CI: 0.93-1.47). Conclusion: A positive association between IBD and dementia was found in patients followed in general practices in Germany.