[Hypertension and dementia]

Prevention and treatment of dementia has turned into a major public health challenge. Several epidemiological studies have indicated a significant association between the presence of hypertension and the onset of dementia (vascular or Alzheimer's type) several years later. Cognitive disorder may be related to focal cerebral lesions of vascular origin (infarctus, lacunae) and/or chronic ischemia of the white matter (white matter lesions) related to arteriosclerosis and/or lipohyalinosis of small perforating arteries high blood pressure in mid-life to later cognitive decline and dementia. Moreover, disorders of cerebral microcirculation and endothelial dysfunction may be associated to blood brain barrier dysfunction and amyloid plaques formation leading to Alzheimer's process. Few randomized clinical trials have included a cognitive assessment and dementia as outcome in their design. They all raise some major criticisms: cognitive assessment was never the main outcome, too short follow-up to study dementia; incomplete assessment of cognition, lost of follow-up and a small proportion of subjects at risk for dementia at inclusion. However, the results of therapeutic trials (SYST-EUR, PROGRESS) open the way to the prevention of dementia (vascular or Alzheimer's type) or cognitive decline by antihypertensive treatments. A meta-analysis including randomized controlled studies, suggests a significant decrease in the risk of dementia with antihypertensive treatment compared to placebo.