Preventing dementia: role of vascular risk factors and cerebral emboli

Dementia, Alzheimer's disease and vascular dementia being two main causes, is major and growing health problem. Vascular risk factors are thought to be involved in the causation of both dementias.

A review of the literature was conducted using MedLine to identify current evidence for role of vascular risk factors as potential targets in preventing dementia. Cross-references were hand searched.

The evidence from prospective epidemiological studies suggests that optimizing the control of vascular risk factors such as hypertension, high cholesterol, diabetes, smoking and heart disease may prevent dementia. However, this has been proven in randomized placebo-controlled trials (RCT) for only hypertension.

Dementia is a secondary outcome in most RCTs and it is not known if there is a therapeutic time window between mid- and late-life when interventions are most effective. Also, we do not know precise mechanisms by which interventions for vascular risk factors offer brain protection.

Our research suggests that asymptomatic cerebral emboli, which are preventable, may be involved in the causation of dementia.

There is a need for RCT targeting multiple vascular risk factors in patients at high risk of dementia such as those with mild cognitive impairment.