In Japan, half of all dementia comes from damaged blood vessels
Vascular dementia is what happens when a string of strokes, some too small to notice, starves patches of brain of oxygen and glucose. It is the second most common dementia in older adults, and in Japan it accounts for half of all cases. Unlike most dementias, it is at least partly preventable.
The damage can come from blockages or bleeds. Some people suffer a series of small strokes across several regions, known as multi-infarct dementia; others accumulate injury in tiny vessels deep in the brain. Decline often arrives in steps, each drop following a new stroke, and the changes typically unfold over 5 to 10 years. A past stroke raises dementia risk by around 70 percent, a recent one by around 120 percent, and a quarter of stroke survivors develop new dementia within a year. A 2018 meta-analysis pooling millions of participants confirmed stroke as a strong, independent and potentially modifiable risk factor.
Its profile differs from Alzheimer's disease. Because small vessel disease often hits the frontal lobes, people struggle more with tasks like verbal fluency and may show apathy, lack of initiative, slowed thinking and repetitive behaviour, while their free recall tends to be better and less error-prone. Apathy early on is a clue pointing towards a vascular cause. Physical signs can include weakness on one side, stiff reflexes, and problems with walking or swallowing. The two diseases frequently overlap, producing mixed dementia.
Prevalence is about 1.5 percent in Western countries and roughly 2.2 percent in Japan, and it makes up 20 to 40 percent of dementia in Europe and 15 percent in Latin America. Around 80 percent of patients have a history of high blood pressure; other risks include age, smoking, high cholesterol, diabetes, heart disease and the APOE-ε4 gene variant. Brain scans such as SPECT can help separate it from Alzheimer's.
Lost tissue does not recover, but patients can go through stable stretches or even mild improvement. As of 2025 no drug specifically prevents or treats vascular dementia, so the focus is on preventing further strokes by controlling blood pressure, blood fats, atrial fibrillation and diabetes. A 2023 review found statins did not prevent stroke or dementia in people without prior cerebrovascular disease. Survival is comparable to or worse than in Alzheimer's, and poorer for men and older patients.
Source: Vascular dementia
