Biomed & Pharmacother 1997;51:68-73 0 Elsevier, Paris Dossier “Aging” Blood pressure and dementia in the elderly: epidemiologic perspectives Z Guo, M Viitanen, L Fratiglioni, B Winblad Stockholm Gerontology Research Center and Department of Geriatric Medicine, Karolinska Institute, Box 6401, S-11382 Stockholm, Sweden Summary - High blood pressure is associated with an increased risk of vascular dementia as a result of ischemic stroke and other cerebrovascular events or lesions. However, there is insufficient epidemiologic evidence indicating that blood pressure is involved in the etiology of Alzheimer’s disease. Clinical studies suggest that episodes of hypotension may cause cerebral hypoperfusion and play a role in the development of dementia. Lowering of blood pressure in dementia, especially Alzheimer’s disease, may be due to the dementia process itself or to the characteristics of the disease. Recent large clinical trials have shown that antihypertensive drugs may not significantly affect cognitive performance, but no data are available regarding their potential effects in decreasing the risk of dementia by lowering the incidence of cerebrovascular events. Some data suggest that the blood pressure-dementia relationship may be age-dependent. Alzheimer’s disease / vascular dementia I hypertension / hypotension INTRODUCTZON Recent studies suggest that dementia of vascular etiology may be more common than previously reported [l], especially in the very old [2]. There is considerable public health interest in vascular causes of dementia because they are potentially treatable and preventable. A number of vascular factors may be associated with dementia. Hyper- tension is believed to be the most powerful risk factor for vascular dementia [3]. However, the re- lationship between blood pressure and dementia is more complicated than previously thought. Both high and low blood pressure may play a role in the pathogenesis of dementia. In addition, it seems that the dementia process itself may alter the blood pressure level. This review will sum- marize the recent clinical and epidemiologic re- sults regarding the relationship between blood pressure and dementia. HYPERTENSION AS RISK FACTOR FOR DEMENTIA Chronic hypertension is associated with adaptive and degenerative structural changes in the cere- bral resistance vessels such as atherosclerosis, wall thickening, luminal narrowing, hypertrophy of smooth muscle and lipohyalinosis. These changes may result in single or multiple cerebral infarcts that vary in size [4]. The bulk of epi- demiologic evidence indicates that hypertension is the most important treatable risk factor for stroke [5]. Hypertension is also thought to play a pathogenetic role in the development of peri- ventricular white matter lesions by promoting arteriolosclerosis, which in turn impairs autoregu- lation, thereby rendering the periventricular white matter vulnerable to ischemia due to hypoten- sion [6]. The white matter changes detected by computed tomography (CT) or magnetic reso- nance imaging (MRI) are seen in most cases of vascular dementia (VaD) and a large number of patients with Alzheimer’s disease (AD), suggest- ing that these lesions may contribute to the cognitive deficits associated with these dis- orders [7-91. Hypertension, stroke and VaD There is little doubt that stroke is an important risk factor for the development of dementia. In hospitalized cohorts of nondemented patients, ischemic stroke increases the risk of dementia by