Inflammatory bowel disease implicated in all-cause dementia risk

Patients with both types of inflammatory bowel disease (IBD) are at risk of all-cause dementia risk, particularly frontotemporal dementia in Crohn’s disease (CD) patients, but this association may be attributed to frequent healthcare system contacts by patients with IBD detection bias, according to a study.

The study drew data from a nationwide population-based cohort study in Denmark (1977–2018) and included all patients with incident IBD (n=88,985; 69.6 percent with ulcerative colitis [UC], 30.4 percent with CD) matched with up to 10 general population comparators without IBD (n=884,108).

Researchers treated death as competing risk to calculate the cumulative incidence proportions (CIPs) of dementia. They also assessed the impact of IBD severity, steroid use, colorectal and small bowel surgery, and healthcare system contacts on dementia risk in a nested case–control analysis.

Incident dementia was documented in 2,076 IBD patients (78.1 percent with UC) and 23,011 controls (76.6 percent UC comparisons). The 40-year CIP of all-cause dementia was 7.2 percent for UC patients and 5.8 percent for CD patients.

Compared with controls, UC patients had slightly increased risks of all-cause dementia (hazard ratio [HR], 1.07, 95 percent confidence interval [CI], 1.01–1.12) and Alzheimer's disease (HR, 1.10, 95 percent CI, 1.01–1.19). On the other hand, CD patients had increased risks of all-cause dementia (HR, 1.15, 95 percent CI, 1.05–1.27) and frontotemporal dementia (HR, 2.70, 95 percent CI, 1.44–5.05).

Notably, dementia in IBD patients was associated with frequent healthcare system contacts.