Journal Article Annotations
2022, 3rd Quarter

GI Psychiatry

Annotations by Ashwini Nadkarni, MD
October, 2022

Risk of dementia in patients with inflammatory bowel disease: a Danish population-based study.

PUBLICATION #1 — GI Psychiatry

Risk of dementia in patients with inflammatory bowel disease: a Danish population-based study.

Jakob Rønnow Sand, Frederikke Schønfeldt Troelsen, Erzsébet Horváth-Puhó, Victor W Henderson, Henrik Toft Sørensen, Rune Erichsen

Abstract: Aliment Pharmacol Ther. 2022 Sep;56(5):831-843. doi: 10.1111/apt.17119. Epub 2022 Jul 3.

Background:
Inflammatory bowel disease (IBD) may be associated with increased dementia risk, but the literature is conflicting.

Aim:
To investigate dementia risk in patients with IBD.

Methods:
We conducted a nationwide population-based cohort study in Denmark (1977-2018) including all patients with incident IBD matched with up to 10 general population comparators without IBD by sex, year of birth and region of residence. We calculated cumulative incidence proportions (CIPs) of dementia treating death as a competing risk, and adjusted hazard ratios (HRs) comparing IBD patients with matched comparisons. In a nested case-control analysis, we investigated the impact of IBD severity, steroid use, colorectal and small bowel surgery, and healthcare system contacts on dementia risk.

Results:
Of 88,985 patients with IBD (69.6% with ulcerative colitis [UC], 30.4% with Crohn’s disease [CD]) and 884,108 comparisons, 2076 patients (78.1% with UC) and 23,011 comparisons (76.6% UC comparisons) developed dementia. The 40-year CIP of all-cause dementia was 7.2% for UC patients and 5.8% for CD patients. UC patients had a slightly increased HR of all-cause dementia (HR = 1.07 [95% confidence interval (CI): 1.01;1.12]) and Alzheimer’s disease (HR = 1.10 [95% CI: 1.01-1.19]). CD patients had an increased HR of all-cause dementia (HR = 1.15 [95% CI: 1.05-1.27]) and frontotemporal dementia (HR = 2.70 [95% CI: 1.44-5.05]). Dementia in IBD patients was associated with frequent healthcare system contacts.

Conclusions:
UC and CD are associated with slightly increased all-cause dementia risk, particularly frontotemporal dementia in CD patients. Frequent healthcare system contacts by patients with IBD and detection bias may play a role in the association.

Keywords:
Alzheimer’s disease; Crohn’s disease; dementia; epidemiology; frontotemporal dementia; inflammatory bowel disease; ulcerative colitis.

Annotation

The finding:
This nationwide cohort study used a database of the entire Danish population (1977-2018) to examine the association between IBD and dementia, including less common dementia subtypes. In a nested case–control analysis, the authors also examined the impact of IBD severity, colorectal or small bowel surgery, steroid use and frequency of healthcare system contacts on dementia risk. Ulcerative colitis patients were found to have a slightly increased risk of Alzheimer’s disease while Crohn’s Disease patients had an increased risk of frontotemporal dementia.

Strength and weaknesses:
This study is the first to investigate the risk of frontotemporal dementia and Parkinson’s disease dementia/Lewy body disease in IBD patients. However, the validity of this study was threatened by the higher frequency healthcare system contact among IBD patients—perhaps IBD patients are more likely to be diagnosed. Finally, the authors did not have access to data on educational level, personal income level, employment status and lifestyle covariables including smoking, alcohol consumption and dietary habits from the included Danish registries.

Relevance:
The study suggests that patients who have IBD are at risk of developing further neuropsychiatric diseases such as dementia. This relationship may relate to the negative impact of chronic inflammation on hippocampal neurogenesis, which is thought to underlie the behavioral sequelae of IBD. C-L psychiatrists caring for the geriatric IBD patient population should be attentive to cognitive impairments, whether owing depression, mild cognitive impairment, or early symptoms of dementia.