APOE and Parkinson disease: In the analysis of genetic predictors in PD only, the MAPT H1/H1 haplotype was associated with increased risk of delirium (HR 2.08, 95% CI 1.08–4.00) and APOE ε4 carrier status was associated with increased risk of delirium (HR 2.16, 95% CI 1.15–4.08).