Persistent poor sleep has been linked to an increased risk of dementia, as new research suggests it may impede the brain's ability to clear out waste. Scientists revealed that the glymphatic system, responsible for flushing out 'toxic material' by circulating cerebrospinal fluid (CSF) through brain tissue and the spinal cord, is crucial for maintaining brain health. Disruption to this vital cleaning system has been found to impair its function, consequently raising the likelihood of developing dementia.

UK scientists, after analyzing the brain structures of over 40,000 adults, found that impaired glymphatic function correlated with a build-up of amyloid and tau proteins. These toxic proteins are known to spread throughout the brain, causing memory problems and forming plaques and tangles that interfere with brain cell function. This process is thought to be a primary driver of Alzheimer's disease, the most common form of dementia.

The findings, published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, underscore the critical role sleep plays in glymphatic function. Disrupted sleep patterns are therefore likely to damage this system, increasing the risk of protein accumulation. The research also suggests that these insights could pave the way for repurposing existing medicines or developing new ones to enhance glymphatic function.

Dr. Yutong Chen, an expert in clinical neurosciences at the University of Cambridge and a study co-author, emphasized the significance of the findings, stating, "Although we have to be cautious about indirect markers, our work provides good evidence in a very large cohort that disruption of the glymphatic system plays a role in dementia." Dr. Hui Hong, another co-author, added that the study provides a likely explanation for why small vessel disease in the brain accelerates conditions like Alzheimer's, by impairing the brain's ability to clear amyloid and tau.

Researchers employed an algorithm developed by Dr. Chen to assess glymphatic functions from MRI scans. Applying this algorithm to 40,000 MRI scans, they identified three biomarkers associated with impaired glymphatic function that could predict an increased dementia risk. These included DTI-ALPS (a measure of water molecule diffusion around blood vessels), the size of the choroid plexus (where CSF is produced), and the flow velocity of CSF into the brain.

Further analysis revealed that several cardiovascular risk factors, such as high blood pressure, also impaired glymphatic function and increased dementia risk. This suggests that strategies to improve CSF dynamics, including improving disrupted sleep patterns and prompt treatment of high blood pressure, may effectively reduce dementia risk. These findings are also slated for presentation at the World Stroke Congress 2025 in Barcelona.

Professor Bryan Williams, chief scientific and medical officer at the British Heart Foundation, which helped fund the study, noted that the research offers a fascinating glimpse into how problems with the brain's waste clearance system could quietly increase the chances of developing dementia. He highlighted that the study opens exciting new avenues for research into treating and preventing dementia, while also stressing the importance of managing known cardiovascular risk factors.

Dementia affects a significant population; University College London scientists estimate 1.7 million Britons will be living with dementia by the year 2040. Alzheimer's Disease alone affects 982,000 people in the UK. Early symptoms often include memory problems, thinking and reasoning difficulties, and language problems, which worsen over time. Alzheimer's Research UK analysis indicated that dementia was the country's biggest killer in 2022, with 74,261 deaths. Globally, new cases of Alzheimer's and other dementias rose by approximately 148 percent from 1990 to 2019, with total cases increasing by around 161 percent, according to figures from Frontiers.