Evidence from a Mendelian randomization study: Delirium’s noncausal role in dementia onset

Abstract

Background

Previous observational studies have suggested a possible association between dementia and delirium. However, these findings might be influenced by confounding variables. Thus, our study aimed to investigate the causal relationship between dementia and delirium using a bidirectional Mendelian randomization (MR) analysis.

Methods

In our investigation, bidirectional MR analysis was conducted by summary statistics from genome–wide association studies (GWAS). This enabled us to evaluate the causal impact of delirium and different types of dementia, such as Alzheimer’s dementia (AD), vascular dementia (VaD) and Lewy body dementia (LD).

Results

According to MR analysis, there was a significant positive correlation between delirium risk and AD (odds ratio [OR] = 1.363; 95 % confidence interval [CI], 1.223–1.519; p = 2.140E-08) and LD (OR = 1.403; 95 % CI, 1.151–1.711; p = 8.226E-04). However, the analysis also revealed that there was no causal relationship between VaD (OR = 1.044; 95 % CI = 1.136–1.027; p = 0.316) and the risk of delirium. Additionally, our study does not provide evidence to support a causal correlation between delirium and the risk of developing any form of dementia.

Conclusion

The results of the MR analysis suggest a potential causal link between dementia and an increased risk of delirium. Nevertheless, it should be emphasized that the existing evidence does not provide support for a causal connection in the reverse direction, implying that delirium may not play a causative role in the onset of dementia.