Brain fluid structure may flag future dementia risk years before diagnosis

by Ingrid Fadelli, Medical Xpress

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Dementia, a progressive loss of memory and decline in mental function that can be caused by various neurological conditions, is estimated to affect more than 57 million people worldwide. Identifying specific biological and neural markers of this condition could help estimate the risk that individuals will develop it and potentially enable early interventions aimed at delaying its emergence or slowing its progression.

Researchers at Shandong First Medical University & Shandong Academy of Medical Sciences recently found that changes in the choroid plexus, a network of specialized cells located inside the brain's fluid-filled cavities (i.e., ventricles), could predict the risk of future dementia.

Their paper, published in Molecular Psychiatry, suggests that people with a larger choroid plexus are significantly more likely to develop dementia.

"Our study was inspired by the growing recognition that impaired clearance of toxic proteins, such as amyloid-β, is a key feature of Alzheimer's disease," Yongxiang Wang, senior author of the paper, told Medical Xpress.

"Because the choroid plexus produces most of the cerebrospinal fluid that facilitates this clearance process, we wondered whether structural changes in the choroid plexus might represent an early sign of dementia and contribute to its development."

Probing the link between the choroid plexus and dementia

Past studies exploring the relationship between dementia and the choroid plexus specifically compared the size of this brain structure in people with dementia and those who were not diagnosed with dementia. The extent to which changes to the choroid plexus precede the onset of dementia therefore remained unclear.

"Previous studies did not ascertain whether structural alterations of the choroid plexus precede dementia onset, contribute causally to the development of dementia and through which pathways they may exert their effects," explained Wang. "To address these knowledge gaps, we examined the associations of choroid plexus volume and MRI signal intensity with future dementia risk and explored the role of structural brain alterations in these associations."

As part of their study, Wang and his colleagues analyzed brain scans collected from more than 45,000 middle-aged and older adults living in the United Kingdom, which were stored in a large database called the UK Biobank. They specifically looked at the volume (i.e., size) of the participants' choroid plexus and the intensity of T1 MRI signals (i.e., signals that offer information about the characteristics and integrity of brain tissue).

"We then followed all participants who were free of dementia at the start of the study for several years to identify those who later developed dementia," said Wang. "We also assessed changes in cognitive performance during follow-up, including memory and reasoning, and examined brain MRI measures of neurodegeneration such as brain atrophy."

To determine whether the size and structural integrity of the choroid plexus predicted the risk of future dementia, the team analyzed the participants' brain scans, hospital records and any available death records using two complementary approaches.

"First, we applied Mendelian randomization, a genetic method that helps infer whether the observed associations are consistent with a potential causal relationship rather than simple correlation," said Wang. "Second, we performed mediation analyses to examine whether brain atrophy could help explain the link between choroid plexus abnormalities and dementia risk."

New potential biomarker of dementia and brain aging

The researchers' analyses yielded various interesting findings. First, they showed that individuals with a larger choroid plexus or lower MRI T1 signal intensity in this structure had a substantially higher risk of experiencing cognitive decline and dementia in the future. This risk appeared to be particularly high for Alzheimer's disease, a neurodegenerative condition that is among the most common causes of dementia.

"Our genetic analyses also provide evidence supporting a potential causal role of choroid plexus alterations in dementia," said Wang. "Our study also linked choroid plexus abnormalities to brain atrophy, a hallmark of Alzheimer's disease, suggesting one possible pathway through which structural choroid plexus alterations may contribute to neurodegeneration."

The recent work by Wang and his colleagues could potentially inform the development of new tools that estimate the risk of future dementia by analyzing brain imaging scans, particularly those focused on the choroid plexus. Other research groups might soon try to validate the team's findings by analyzing the brain scans of other patient cohorts.

"If our results are confirmed by future studies, future measures could help improve risk stratification and support earlier intervention, ultimately contributing to effective interventions to delay dementia," added Wang.

"Meanwhile, we plan to further explore the neurobiological mechanisms underlying the link between structural abnormalities of the choroid plexus and subsequent cognitive decline and dementia. This could be achieved by using Alzheimer's disease-specific biomarkers, such as amyloid and phosphorylated tau proteins measured in blood or cerebrospinal fluid, or by PET imaging."

Written for you by our author Ingrid Fadelli, edited by Sadie Harley, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you.

Publication details

Tianyu Yu et al, The choroid plexus, cognitive decline, and incident dementia: insights from the UK Biobank, Molecular Psychiatry (2026). DOI: 10.1038/s41380-026-03739-5.

Journal information: Molecular Psychiatry

Key medical concepts

Choroid PlexusDementiaAlzheimer's DiseaseBrain atrophy

Clinical categories

NeurologyHealthy agingDiagnostic radiologyCommon illnesses & Prevention Who's behind this story?

Ingrid Fadelli

Freelance journalist with BSc Psychology and MA International Journalism. Covers AI, robotics, neuroscience, and astrophysics since 2018. Full profile →

Sadie Harley

BSc Life Sciences & Ecology. Microbiology lab background with pharmaceutical news experience in oil, gas, and renewable industries. Full profile →

Robert Egan

Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →

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