This is to be expected given the close relationship of the two disorders6, but it may hide delirium-specific genetic effects and overemphasize the role of APOE. To this end, APOE remained significant in our range of sensitivity analyses (GWAS adjusting for all-cause dementia (Extended Data Fig. 3), mediation analysis (Fig. 4), dementia and AD-stratified GWAS (Extended Data Figs. 4–5 and Supplementary Table 2)) although with weaker effect. This evidence concerns the gene APOE and Alzheimer disease.