For those with absent or mild WMD, the lasso analysis did not include hospitalisation with infection as a covariate in the model, and hospitalisation with delirium continued to be predictive of dementia (aHR 2·75, 95% CI 1·75–4·31; p<0·0001) after adjusting for age, gender, education level, baseline cognition, APOE genotype, and comorbidities. This evidence concerns the gene APOE and delirium.