Public health importance of vascular dementia and Alzheimer's disease with cerebrovascular disease.

Vascular dementia (VaD) refers to a heterogeneous group of conditions that include all dementia syndromes resulting from ischaemic, haemorrhagic, anoxic or hypoxic brain damage. VaD is the second most common cause of dementia in the elderly after Alzheimer's disease. Persons with VaD are at greater risk of morbidity and mortality compared with those without dementia or those with Alzheimer's disease, and appear to be at greater risk of institutionalisation. Despite the importance of the problem posed by VaD, few placebo-controlled, double-blind, randomised clinical trials have been conducted. Although dementia may result solely from the accumulation of brain damage from cerebrovascular disease (CVD), recent data suggest that VaD often results from a combination of both CVD and Alzheimer's disease ('mixed' dementia). This raises the possibility that persons with VaD may respond to medications that are commonly used to treat Alzheimer's disease.