APOE and Alzheimer disease: This may explain why a recent report failed to show an association of APOE-ε4 and the development of dementia in a cohort that the authors note was underrepresented for early dementia cases.33 Similar observations have also been made in AD, showing the APOE genotype–related risk for AD decreases significantly with age,34 and would support the importance of early initiation of neuroprotective treatment (when available) in APOE-ε4 carriers.