Inflammatory bowel disease and dementia: Evidence triangulation from a meta-analysis of observational studies and Mendelian randomization study
Abstract
Objective: Observational studies have found associations between inflammatory bowel disease (IBD) and the risk of dementia, including Alzheimer's dementia (AD) and vascular dementia (VD); however, these findings are inconsistent. It remains unclear whether these associations are causal. Methods: We conducted a meta-analysis by systematically searching for observational studies on the association between IBD and dementia. Mendelian randomization (MR) analysis based on summary genome-wide association studies (GWASs) was performed. Genetic correlation and Bayesian co-localization analyses were used to provide robust genetic evidence. Results: Ten observational studies involving 80,565,688 participants were included in this meta-analysis. IBD was significantly associated with dementia (risk ratio [ RR] =1.36, 95% CI = 1.04-1.78; I2 = 84.8%) and VD ( RR = 2.60, 95% CI = 1.18-5.70; only one study), but not with AD ( RR = 2.00, 95% CI = 0.96-4.13; I2 = 99.8%). MR analyses did not supported significant causal associations of IBD with dementia (dementia: odds ratio [ OR] = 1.01, 95% CI = 0.98-1.03; AD: OR = 0.98, 95% CI = 0.95-1.01; VD: OR = 1.02, 95% CI = 0.97-1.07). In addition, genetic correlation and co-localization analyses did not reveal any genetic associations between IBD and dementia. Conclusion: Our study did not provide genetic evidence for a causal association between IBD and dementia risk. The increased risk of dementia observed in observational studies may be attributed to unobserved confounding factors or detection bias.
RAS ID
78480
Document Type
Journal Article
Volume
38
Issue
1
PubMed ID
39924155
School
Centre for Precision Health
Copyright
free_to_read
Publisher
Elsevier
Comments
Liu, D., Cao, M., Wu, S., Li, B., Jiang, Y., Lin, T., ... & Tang, J. (2025). Inflammatory bowel disease and dementia: Evidence triangulation from a meta-analysis of observational studies and Mendelian randomization study. Biomedical and Environmental Sciences, 38(1), 56-66. https://doi.org/10.3967/bes2024.149