Vascular dementia is a disease caused by cardiovascular and cerebrovascular diseases and their risk factors. The relevant risk factors that cause cardiovascular and cerebrovascular diseases have to be mentioned as the "three highs".

1. Hypertension: High blood pressure can narrow or even block brain arteries, increasing the risk of ischemic stroke and the incidence of vascular dementia.

2. Hyperlipidemia: Elevated cholesterol levels not only damage arterial and capillary wall function, accelerating atherosclerosis and impairing brain blood supply, but also lead to neuronal degeneration and the production and deposition of amyloid protein, resulting in cognitive impairment and dementia. 

3. Hyperglycemia: Prolonged high blood sugar levels can damage endothelial cells of blood vessels, increasing the risk of atherosclerosis and causing cerebral ischemia, ultimately leading to vascular dementia.