[Lipid abnormality].

Vascular dementia is caused by stroke, so primary and secondary prevention for stroke is extremely important. Effects of statins on stroke prevention in patients are reported from recent randomized controlled trials. Hypercholesterolemia in midlife are related to an increased risk of Alzheimer's disease (AD) in later life. During the past decade, effects of statins for patients with AD are controversial in many subsequent original studies. Accordingly, it remains unknown whether statin therapy have a preventive effect on cognitive decline in patients with AD. As a possible mechanism, hypercholesterolemia may be associated with the progression of AD pathology. As another possible mechanism hypercholesterolemia may be associated with hypoperfusion through the progression of atherosclerosis.