Changes in a little-known brain structure called the choroid plexus may be linked to cognitive decline and the future development of dementia, according to a new study based on more than 45,000 participants from the UK Biobank.
The research, published in Molecular Psychiatry, examined whether characteristics of the choroid plexus—a structure involved in producing cerebrospinal fluid and maintaining the brain’s internal environment—were associated with dementia risk and age-related changes in the brain.
As the authors noted, the choroid plexus plays a crucial role in cerebrospinal fluid secretion and the maintenance of brain homeostasis, and its structure and function have been implicated in dementia, though its long-term relationship with the disease has remained unclear.
To investigate, researchers analyzed data from over 45,000 middle-aged adults who underwent detailed brain MRI scans. The team measured both the volume of the choroid plexus and its signal intensity on MRI scans, then compared those measures with participants’ cognitive performance, brain structure, and future dementia diagnoses identified through linked health records.
The study found that the choroid plexus changed with age. Older participants tended to have a larger choroid plexus volume and lower signal intensity.
Those differences also appeared to be linked to dementia risk.
Researchers found that people with a larger choroid plexus were more likely to develop all-cause dementia during follow-up, while those with higher choroid plexus signal intensity were less likely to do so.
The findings suggest that the choroid plexus may not simply reflect brain aging but could be involved in processes linked to dementia development.
The study does not suggest that choroid plexus changes alone determine whether a person will develop dementia. Instead, the results indicate that these measurements are connected to broader changes occurring throughout the brain, including in regions involved in memory and cognition.
Dr. George Hennawi, physician executive director of the MedStar Health Center for Successful Aging, told Newsweek that the possibility of identifying risk before symptoms appear would represent a major shift in dementia care.
“As far as the significance, it will be an earth-shattering finding because most of the time what we have today, even with the biomarkers and PET scans, is reactive,” Hennawi said. “We detect the change after either the clinical symptoms have started or the cell damage has happened.”
He said the goal in dementia research is to move toward predicting who is at risk before damage has already occurred, rather than identifying disease after symptoms or measurable cell injury have developed.
“What we’re hoping to do eventually in the world of dementia is to predict risk. Predict who is at risk of developing dementia, whether it’s Alzheimer’s or other types of related dementias and intervene before the damage happens. That’s what we’re hoping for. That is huge!” Hennawi said.
The distinction between a potential risk marker and a test that can definitively predict dementia is important. The study points to an association between choroid plexus characteristics and later dementia risk, but it does not establish a standalone diagnostic or predictive test.
Hennawi said current tools generally detect signs of existing damage rather than forecasting risk far enough in advance to prevent that damage.
“The markers that we have today predict damage, whether amyloid markers, or tau protein markers, or other available tools. The risk prediction is the future,” Hennawi said. “What I mean by that is you need to predict who is going to be at risk of developing dementia before the cell damage happens.”
He added that researchers still need to determine whether risk can be predicted objectively decades before symptoms develop, and whether that knowledge can lead to effective prevention or treatment strategies.
“I think the key questions remain related to our understanding of targeting the risk or predicting risk 20 years before any symptoms develop,” Hennawi said.
He said the field has improved in diagnosing dementia and thinking about how to manage it, but much of that progress still applies after decline has already begun.
“The key for the researchers is; can we predict risk objectively, scientifically, then can we create a pathway for prevention or treatment that is effective in mitigating that risk?” Hennawi said. “It’s good to figure out that I’m at risk for a disease but if there’s no treatment, it will continue to be a dead end.”
The study’s authors concluded that choroid plexus characteristics may serve as useful biomarkers of structural brain aging and dementia risk. For Hennawi, findings like these are part of a broader effort to understand the disease earlier and intervene more effectively.
“From someone who specializes in dementia, it’s a challenging disease, it takes a toll on the patients, their families and their communities,” Hennawi said. “But I feel optimistic that we’re starting to crack that code.”
Reference:
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.