Brain arterial dilatation and the risk of Alzheimer's disease

Introduction: We tested the hypothesis that brain arterial dilatation increases the risk of Alzheimer's dementia (AD). Methods: We studied dementia-free participants in the Washington Heights-Inwood Columbia Aging Project who had a brain MRI and post-MRI dementia adjudication. We measured the axial T2-proton density diameters of the intracranial carotids and basilar diameters and used Cox models to obtain AD hazard ratios and 95% intervals. Results: Of 953 participants (mean age 77 ± 7 y, women 64%, 71% nonwhite)followed on average for 3 ± 3 years, 76 (8%)developed AD. In a model adjusted for demographics, vascular risks, apolipoprotein E (APOE)-ε4, and white matter hyperintensities, larger carotid diameters increased the risk of AD, defined categorically as ≥ 90th percentile (HR 4.34, 1.70–11.11)or continuously (HR 1.44 per SD, 1.07–1.94). Discussion: Understanding the pathophysiology of the association between AD and brain arterial dilatation may reveal new clues to the vascular contributions to AD.