The prevalence and incidence of degenerative and vascular dementia increase exponentially with age. Several studies in recent years have implicated hypertension as a risk factor not only for vascular dementia but also for degenerative dementia such as Alzheimer's disease. This is an important finding because it suggests that the treatment of hypertension could reduce the incidence of dementia. In particular, the results of the Syst-Eur study, showing that a calcium inhibitor, nitrendipine, could reduce not only the incidence of stroke but also that of dementia, should be confirmed.