Nikhil Prasad Fact checked by:Thailand Medical News Team Jul 29, 2026 36 minutes ago
Medical News: Researchers from Shandong First Medical University and Shandong Academy of Medical Sciences in China have identified a promising brain imaging marker that may help predict who is at higher risk of developing dementia years before symptoms appear. By analyzing MRI brain scans from more than 45,000 adults in the United Kingdom, the team discovered that subtle structural changes in a little-known brain tissue called the choroid plexus were strongly linked to future cognitive decline and dementia, especially Alzheimer's disease.
MRI-detectable changes in the brain's choroid plexus may reveal dementia risk years before memory problems begin
This
Medical News report highlights growing evidence that dementia begins silently many years before memory loss becomes obvious. The findings suggest that monitoring the choroid plexus using routine MRI scans could eventually help doctors identify people at high risk much earlier, when preventive strategies may be most effective.
The overlooked brain structure that may hold important clues
The choroid plexus is a specialized tissue located inside the brain's fluid-filled chambers called ventricles. Although it receives far less attention than brain regions such as the hippocampus, it performs one of the brain's most essential jobs—it produces most of the cerebrospinal fluid that cushions the brain, transports nutrients, removes waste products, and helps maintain a healthy brain environment.
Scientists have become increasingly interested in this structure because cerebrospinal fluid plays a key role in clearing harmful proteins such as amyloid-beta and phosphorylated tau, two proteins that accumulate in Alzheimer's disease. If the choroid plexus becomes damaged or functions poorly with age, this waste-clearing system may gradually fail, allowing toxic proteins to build up and damage brain cells.
A massive long-term study involving more than 45,000 people
The researchers analyzed MRI scans from 45,306 dementia-free participants in the UK Biobank, with an average age of 64 years. Using advanced MRI analysis software, they measured both the size of the choroid plexus and its MRI signal intensity, an indicator of tissue integrity.
Participants were followed for several years, with researchers monitoring hospital records, death registries, and repeated cognitive testing to determine who later developed dementia. They also examined brain shrinkage, white matter damage, and changes in memory, reasoning ability, executive function, and working memory over time. Sophisticated statistical methods, including Mendelian randomization, were used to determine whether the observed relationships were likely to be causal rather than simple coincidence.
Larger choroid plexus strongly increased dementia risk
One of the most striking findings was that individuals with an enlarged choroid plexus were 61% more likely to develop dementia than those with smaller structures. In contrast, people whose choroid p
lexus showed higher MRI signal intensity—a sign of healthier tissue—had substantially lower dementia risk.
The association was especially strong for Alzheimer's disease. Importantly, these structural changes appeared years before clinical diagnosis, suggesting they could serve as early warning signs rather than simply reflecting existing disease. The genetic analyses also supported the possibility that abnormalities in the choroid plexus actively contribute to dementia development rather than merely occurring alongside it.
Brain shrinkage and white matter damage explain much of the risk
The researchers found that alterations in the choroid plexus were closely linked to many well-known markers of brain aging.
People with larger choroid plexuses showed greater shrinkage of critical memory-related regions, including the hippocampus, amygdala, and nucleus accumbens. These structures are among the earliest areas affected during Alzheimer's disease.
They also had more extensive white matter hyperintensities—areas of damage often associated with poor blood vessel health—as well as deterioration of microscopic white matter fibers that connect different brain regions. Statistical mediation analyses suggested that these structural brain abnormalities explained up to 42.9% of the relationship between choroid plexus changes and dementia risk.
Faster cognitive decline was also observed
The study demonstrated that participants with enlarged choroid plexuses experienced a more rapid decline in several important mental abilities, including working memory, executive function, and fluid intelligence.
Moreover, individuals whose choroid plexus continued enlarging over time experienced even faster deterioration in memory and reasoning performance. Meanwhile, healthier MRI characteristics of the choroid plexus were associated with slower declines in cognitive performance, reinforcing the idea that this structure may play a direct role in preserving brain health during aging.
Why these changes may happen
As people grow older, the choroid plexus undergoes structural deterioration, including thinning of its specialized cells, thickening of supporting membranes, fibrosis, calcification, and impaired barrier function. These age-related changes reduce cerebrospinal fluid production and circulation while weakening the blood-cerebrospinal fluid barrier.
Reduced fluid circulation may impair the brain's glymphatic waste-clearance system, allowing harmful proteins to accumulate. At the same time, barrier dysfunction may permit inflammatory molecules to enter brain tissue, promoting chronic inflammation, injury to white matter, damage to small blood vessels, and progressive loss of neurons in vulnerable brain regions. The researchers believe these combined neurodegenerative and vascular processes likely explain why choroid plexus abnormalities are so strongly associated with dementia development.
Conclusions
This landmark population study provides compelling evidence that structural abnormalities of the choroid plexus may represent one of the earliest detectable imaging biomarkers of dementia risk. Rather than being an innocent bystander, the choroid plexus appears closely involved in the biological processes that drive brain aging, impaired waste removal, inflammation, brain atrophy, and cognitive decline. If future studies confirm these findings across more diverse populations, routine MRI assessment of the choroid plexus could become an important tool for identifying individuals who may benefit from early monitoring, preventive therapies, and lifestyle interventions years before irreversible neurological damage occurs. The work also opens new avenues for developing treatments aimed at preserving cerebrospinal fluid circulation and improving the brain's natural waste-clearing systems.
The study findings were published in the peer reviewed journal: Molecular Psychiatry.
https://www.nature.com/articles/s41380-026-03739-5
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