Title:Hypertension is the Main Vascular Risk Factor for Cognitive Impairment, Microvascular Pathology and Brain Atrophy in Alzheimer’s Disease
Volume: 23
Issue: 1
Author(s): Shailendra Mohan Tripathi*, Helen Shiells, Jennifer Waymont, Roger Staff, Bjoern Schelter, Peter Bentham, Claude M. Wischik and Alison D. Murray
Affiliation:
- Department of Geriatric Mental Health, King George’s Medical University, UP, Lucknow, 226003, India
- Aberdeen
Biomedical Imaging Centre Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen-AB25 2ZD,
United Kingdom
Keywords:
Alzheimer’s disease, hypertension, diabetes, dyslipidemia, FDG-PET, brain atrophy.
Abstract:
Introduction: Alzheimer’s Disease (AD) is the commonest pathology underlying dementia,
but it frequently coexists with cerebrovascular disease (CVD). Existing literature supports
a possible role for vascular risk factors (VRFs), including hypertension, diabetes and dyslipidaemia
in AD pathogenesis. This study aims to determine whether VRFs contribute to typical AD
pathogenesis or co-morbid CVD in mixed AD.
Methods: Well-characterised probable AD subjects participating in two large clinical trials of Hydromethylthionine
were classified into “typical AD” and “mixed” patterns based on FDG-PET images.
VRFs, including hypertension, diabetes and dyslipidaemia, and MRI-derived White Matter
Hyperintensities (WMHs) and brain fraction (as a measure of brain atrophy) were analysed to investigate
the relationship between VRFs and AD subtypes.
Results: Of 794 participants, 533 (67.1%) were classified as typical AD and 261 (32.8%) were
classified as mixed. Among VRFs, cardiovascular risks were significantly more frequent in typical
AD (59%) than in mixed subtype (47%) (p = 0.002).
Discussion: We found that it was mainly hypertension that differed according to subtypes. Although
brain atrophy is the main driver of cognitive impairment in patients with AD subtype, the
microvascular pathology in the form of WMHs was significantly higher in patients with hypertension,
irrespective of subtype.
Conclusion: Although hypertension is the main risk factor for cerebrovascular disease, contrary to
our expectation, hypertension is common in typical AD than the mixed subtype, and this association
is driven by the hitherto unsuspected contribution of microvascular pathology to cognitive impairment
in typical AD.
