New Research: Stroke Doubles Risk of Dementia

What’s the link between stroke and dementia?

We’ve long known that link exists, since stroke and dementia are both conditions that affect the brain.

A stroke is like a heart attack in the brain. Just as a heart attack is caused by interrupted blood flow to the heart, a stroke is caused by interrupted blood flow to the brain. The most common form of stroke is ischemic stroke, when a blood clot blocks the flow of blood. This is what happens in 87 percent of all strokes. When the lack of blood flow is only temporary, a transient ischemic attack (TIA) occurs. This is also known as a mini-stroke, because it lasts only a short time with few, if any, long-term effects.

Dementia is an umbrella condition that involves deterioration of the brain. It includes many different diseases, most common among them Alzheimer’s disease. Vascular dementia is the second most common for of dementia. It doesn’t have a lot of the characteristics of Alzheimer’s disease, but it also causes a decline in cognitive skills. People with vascular dementia experience problems with reasoning, judgment, and memory. Vascular dementia—as its name implies—is related to the vascular, or vein, system. When blood flow to the brain is inadequate, the brain loses oxygen, causing dementia.

As you can see, there is a common cause for stroke and vascular dementia—interrupted blood flow.

New Study Expands Risk Boundaries

Previous studies have shown that stroke and dementia are risk factors for each other. That means having one puts you at higher risk for the other. Risk of dementia was also shown to increase with recurring strokes.

Now, a large-scale study has found that those who experienced a stroke were twice as likely to develop dementia as compared to the general population. Researchers at the United Kingdom’s University of Exeter Medical School conducted a meta-analysis of nearly 50 studies from around the world. Their analysis included a review of over 3 million individuals’ data.

Even after taking other risk factors, such as blood pressure, heart disease, and diabetes, the link persisted.

“Given how common both stroke and dementia are, this strong link is an important finding. Improvements in stroke prevention and post-stroke care may therefore play a key role in dementia prevention,” said University of Exeter Medical School researcher Ilianna Lourida, Ph.D.