Causal effect analysis of the relationship between Alzheimer's diseas (AD) and wet age-related macular degeneration (wAMD)

Alzheimer's disease (AD) and wet age-related macular degeneration (wAMD) are both prevalent degenerative diseases in the elderly population. However, whether AD is causally related to wAMD is unclear. A Mendelian randomization(MR) analysis was conducted to investigate the association between them. Single nucleotide polymorphisms (SNPs) involved in this study were acquired from the IEU Open Genome-wide association study (GWAS) database. As for AD (ID: finn-b-G6_ALZHEIMER), there were 3899 cases and 214,893 controls. For wAMD (ID:finn-b-WET_AMD), it contained 2114 cases and 206,601 controls. The inverse-variance weighted (IVW) method was performed as the major analysis, supplemented by sensitivity analyses and Steiger test. The occurrence of wAMD was associated with decreased risk of AD (IVW, OR was 0.82 at 95%, Confidence interval (CI) of 0.77-0.88, p = 1.67E-09). Our findings demonstrated a potentially protective effect of AD against the development of wAMD. It promotes further investigation of interaction between AD and wAMD.