APOE and Alzheimer disease: Examination of Aβ42 in saliva revealed statistically significant higher levels of Aβ42 in patients with AD,25, 35 alongside high diagnostic accuracy for discriminating AD patients from controls (area under the curve [AUC] = 0.81),57 with sex, but not apolipoprotein E (APOE) or age‐related, differences noted in a previous report.52