Blood pressure, white matter lesions and medial temporal lobe atrophy: closing the gap between vascular pathology and Alzheimer's disease?

BACKGROUND: Vascular factors are recognized as important risk factors for Alzheimer's disease, although it is unknown whether these factors directly lead to the typical degenerative pathology such as medial temporal lobe atrophy. We set out to investigate the relation between blood pressure and medial temporal lobe atrophy in patients with senile and presenile Alzheimer's disease with or without white matter lesions. METHODS: We determined the relation between blood pressure and pulse pressure and medial temporal lobe atrophy on MRI in 159 patients with Alzheimer's disease, stratified on white matter lesions and age at onset of dementia. RESULTS: There was a linear relation between systolic blood pressure and pulse pressure (both in tertiles) and the severity of medial temporal lobe atrophy (p(trend) = 0.05 and p(trend) 0.03, respectively). A significant relation was found between pulse pressure [beta = 0.08 (95% CI: 0.00-0.15; p = 0.05) per 10 mm Hg] and (borderline significant) systolic blood pressure [beta = 0.05 (95% CI: -0.01 to 0.11; p = 0.1) per 10 mm Hg] and medial temporal lobe atrophy. White matter lesions and age-stratified analysis revealed a significant association between systolic blood pressure and pulse pressure and medial temporal lobe atrophy, only in the subsample with white matter lesions and in the subsample with a senile onset of dementia. The relations were independent of severity of dementia and diabetes mellitus. CONCLUSIONS: Systolic blood pressure and pulse pressure are associated with medial temporal lobe atrophy in Alzheimer's disease, especially in the presence of white matter lesions and in patients with a late onset of dementia. Our finding may be another step in providing a rationale on how vascular factors could ultimately result in Alzheimer's disease