Mendelian Randomization Study of the Causal Relationship between PM2.5 and Neurodegenerative Diseases

Background: In recent years, a large number of studies have evaluated the relationship between particulate matter 2.5 (PM2.5) and the incidence rate and mortality of neurodegenerative diseases (NDDs), but the conclusion is controversial. Methods: The publicly available statistical data from genome-wide association studies were used for two sample MR. Inverse variance weighted is used as the main analysis, MR Egger regression, maximum likelihood, simple median, and weighted median are used for supplementary validation. Results: MR analysis results indicate that for every standard deviation increase in PM2.5 exposure, the risk of Alzheimer's disease (AD) increases by 41% (95% CI: 1.10～1.82, P=0.008). However, there is no causal association between PM2.5 and NDDs such as Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and Dementia with Lewy bodies. Sensitivity analysis did not detect heterogeneity and pleiotropy, indicating that the analysis results are robust. Conclusion: There is a causal relationship between PM2.5 and the risk of AD, and reducing PM2.5 exposure may be of great significance for the prevention of AD.