Stroke prevention does reduce the risk of dementia, primarily because stroke and dementia share many common vascular risk factors, and stroke itself significantly increases the likelihood of developing dementia. Preventing strokes by managing these risk factors can therefore help lower dementia risk.
Strokes cause damage to the brain by interrupting blood flow, which leads to brain cell death and cognitive decline. People who have had a stroke are about 55% more likely to develop dementia than those who have not experienced a stroke. This increased risk is independent of other factors, meaning stroke itself is a strong contributor to dementia development. The brain damage from stroke includes microinfarcts (tiny areas of dead brain tissue), white matter changes, and atrophy in critical brain regions like the hippocampus, all of which impair cognitive function. Additionally, stroke can disrupt the blood-brain barrier, leading to inflammation and further brain injury, which also contributes to cognitive decline.
Many of the risk factors for stroke are modifiable and overlap with those for dementia. These include high blood pressure (hypertension), diabetes, high cholesterol (dyslipidemia), smoking, physical inactivity, poor diet, and obesity. Hypertension is often called the “silent killer” because it usually has no symptoms but significantly increases the risk of stroke and dementia. Controlling blood pressure through lifestyle changes and medication can reduce the incidence of stroke and, by extension, lower dementia risk.
Physical activity plays a crucial role in this prevention. Regular aerobic exercise improves cardiovascular health, reduces white matter damage in the brain, and can even increase hippocampal volume, which is important for memory and cognition. After a stroke, engaging in cardiorespiratory exercise has been shown to slow brain atrophy and improve cognitive outcomes, suggesting that exercise is protective against poststroke dementia.
Lifestyle factors beyond physical health also matter. Social engagement, stress management, and good sleep quality contribute to brain health and reduce risks of both stroke and dementia. Tools that assess brain health by combining multiple modifiable factors—such as blood pressure, body mass index, diet, smoking status, sleep, social relationships, and stress—show that people with better scores have significantly lower risks of stroke and dementia.
In summary, stroke prevention through comprehensive cardiovascular risk management—controlling blood pressure, managing diabetes and cholesterol, maintaining physical activity, and adopting healthy lifestyle habits—can substantially reduce the risk of developing dementia. This is because preventing stroke limits brain damage and preserves cognitive function, while also addressing shared risk factors that contribute to both conditions.
