A new study from the University of Cambridge has uncovered a surprising link between the brain’s waste-clearing system and the risk of developing dementia.
The study suggests that when this system doesn’t work properly, it may help explain why poor sleep and problems like high blood pressure raise the chances of getting dementia later in life.
The waste-clearing system in the brain is called the glymphatic system. It was only discovered in 2012. It works by moving a clear liquid called cerebrospinal fluid (or CSF) through the brain.
This fluid flows along tiny channels around blood vessels, collecting waste products and harmful substances. It then carries them away, keeping the brain clean and healthy.
In diseases like Alzheimer’s, toxic materials build up in the brain—such as amyloid plaques and tau tangles. These substances are believed to play a big role in memory loss and cognitive problems. If the glymphatic system doesn’t clear these toxins well, the brain can get overwhelmed, leading to damage over time.
Vascular dementia is another common type of dementia, caused by reduced blood flow in the brain. The main cause of this is called cerebral small vessel disease, which affects tiny blood vessels.
Research has shown that people with both Alzheimer’s and small vessel disease are more likely to show symptoms of dementia than those with just one of these problems.
The researchers wanted to know whether small vessel disease and other heart-related risk factors harm the glymphatic system, which in turn could increase dementia risk. Until recently, scientists could only study the glymphatic system in mice. But thanks to new types of MRI brain scans and smart computer tools, they can now study this in people.
The team used advanced machine learning to analyze MRI brain scans from nearly 40,000 adults in the UK Biobank. They identified three markers that show how well the glymphatic system is working. These included how water moves along the brain’s blood vessels, the size of the part of the brain where CSF is made, and how fast the fluid flows into the brain.
The results showed that people with poor glymphatic function had a higher chance of developing dementia within the next ten years. They also found that heart health problems, like high blood pressure, worsened glymphatic function by causing small vessel disease.
This study provides a possible explanation for why poor heart health increases the risk of dementia. It also points to new ways to help prevent it. For example, improving sleep could help the glymphatic system clear out waste better, since this system works most during sleep. Another idea is to find medicines that can support this system directly.
Treating high blood pressure may be especially important. Earlier research, like the SPRINT MIND trial, showed that lowering blood pressure can reduce the risk of cognitive decline. This new study supports that by showing how high blood pressure might damage the brain’s cleaning system.
In the end, this research highlights how important it is to take care of your heart and your sleep. By doing so, you might also be helping your brain stay healthy for longer.
As Professor Hugh Markus from Cambridge explained, controlling blood pressure and avoiding smoking are simple steps that could improve how the glymphatic system works—possibly lowering the chances of getting dementia.
If you care about dementia, please read studies about Common drug for constipation is linked to higher dementia risk and findings of Scientists find link between heartburn drugs and increased dementia risk.
If you care about dementia, please read studies about Scientists find a drug related to Viagra may help treat vascular dementia and findings of link between body inflammation and dementia risk.
The study is published in Alzheimer’s & Dementia.
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