Alzheimer Disease Occurs More Frequently in Patients with Inflammatory Bowel Disease: Insight from a Nationwide Study

Alzheimer disease (AD) affects 5 million Americans and early recognition improves cognitive function. Chronic inflammation and gut microbiome alteration are linked to cognitive decline which are common in inflammatory bowel disease (IBD). We investigated the association of IBD with development of AD. A commercial database (Explorys Inc., Cleveland, OH), an aggregate of electronic health records from 26 major US health care systems, was surveyed. Cohorts of patients with Systematized Nomenclature of Medicine - Clinical Terms (SNOMED-CT) diagnoses of Crohn's disease (CD), ulcerative colitis (UC), and AD were identified. IBD patients with new diagnosis of AD were characterized based on demographic and traditional AD risk factors and IBD-related features. Among 342,740 IBD patients in the database, AD developed in 5750 IBD patients (1.55%). After adjusting for traditional AD risk factors, IBD was identified as an independent risk factor for development of AD [odds ratio (OR)=2.30, 95% confidence interval (CI)=2.10-2.51]. IBD patients with AD were younger in comparison to AD patients without IBD. On sub-group analysis, patients with CD had higher odds of developing AD (adjusted OR=3.34, 95% CI=3.25-3.42) than UC (adjusted OR=1.09, 95% CI=1.06-1.14). Use of tumor necrosis factor (TNF-α) inhibitors in IBD was associated with significantly lower odds of developing AD in both CD and UC. In this population based study, IBD was independently associated with development of AD. Among IBD; the association was stronger in patients with CD in comparison with UC. Use of TNF-α inhibitors was associated with lower odds of developing AD.