Causal Relationships Between Oral Health Status And Alzheimer’s Disease

Alzheimer's patients demonstrated to have poorer oral health status. However, most of the current observational studies are limited by biases such as potential (residual, unmeasured) confounders, reverse causality, or detection bias. Thus, the correlation between oral health status and AD remains uncertain. In order to explore the potential causal relationship between oral health status and AD in a European population, a two-sample Mendelian randomization (TSMR) approach was adopted. The largest and most recent Genome-Wide Association Study (GWAS) data on mouth ulcer, bleeding gums, chronic periodontitis, and dental caries were selected as a dataset for oral health status from published GWAS studies. The summary data for AD came from the International Genomics of Alzheimer’s Project (IGAP). The main analyzing approach utilized in this study was the Inverse-variance weighted (IVW) method and the alternative methods such as MR-Egger and leave-one-out methods were used as sensitivity analysis methods to ensure the robustness of the results. All MR methods confirmed that there was no significant causal link between oral health status and AD. (P mouth ulcer: 0.559; P bleeding gums: 0.148; P periodontitis: 0.843; P dental caries: 0.213). This MR analysis offers more trustworthy evidence for the association between oral health status and AD at the genetic level, avoiding the drawbacks of previous observational studies and providing a new perspective on etiological analysis.