The prevalence and incidence of degenerative and vascular dementias increase exponentially with age, from 70 years onward. In view of the increasing longevity of humans, both varieties are bound to evolve into a major problem worldwide. According to several longitudinal studies, hypertension appears to predispose individuals to the development of cognitive impairment and ensuing dementia, after a period varying from a few years to several decades. Antihypertensive drug treatment, according to preliminary evidence, may serve to reduce the rates of such events. Such findings await to be confirmed by formal therapeutic trials against a backdrop of "historical" observational sources.,
Archives of Internal Medicine
Erasmus MC: University Medical Center Rotterdam

Birkenhäger, W. H., Forette, F. (Françoise), Seux, M.-L. (Marie-Laure), Wang, J. G., & Staessen, J. (2001). Blood pressure, cognitive functions, and prevention of dementias in older patients with hypertension. Archives of Internal Medicine (Vol. 161, pp. 152–156). doi:10.1001/archinte.161.2.152