2.1. GWAS summary datasets

We sought to evaluate the potential contribution of COVID‐19 to AD using MR analysis of GWAS summary results. The study is based on publicly available GWAS summary results, including SARS‐CoV‐2 infection (112 612 cases, and 2 474 079 controls, with 88.9% of participants being of European origins), hospitalized COVID‐19 (24 274 cases and 2 061 529 controls, with 87.7% participants being of European origin), critical COVID‐19 (8779 cases and 1 001 875 controls, with 94.9% participants being of European origin), and AD (71 880 cases and 383 378 controls). ¹⁰ The COVID‐19 datasets were obtained from the COVID‐19 Host Genetics Initiative (HGI) GWAS. ¹¹ The “SARS‐CoV‐2 infection” label reflects the overall susceptibility to the virus, whereas the “hospitalized” and “critical COVID‐19” labels represent the severity of the disease. Therefore, we collectively called the latter two outcomes “severe COVID‐19.” The effects (values and directions) of single nucleotide polymorphisms (SNPs) were harmonized between each pair of datasets after the exclusion of those with conflicting alleles.