Dementia is usually noticed when a person begins forgetting names, repeating questions, getting lost, or struggling with everyday tasks.
However, scientists now know that the disease starts developing many years before these symptoms appear.
Changes inside the brain can begin 10, 20, or even 30 years before memory problems become obvious.
This means there may be a valuable opportunity to identify people at higher risk while they are still healthy.
A new international study, published in Science Advances, suggests that a simple blood test may one day help doctors do exactly that.
The researchers focused on a blood protein called GDF15. Proteins are natural substances made by the body that carry out many important jobs. GDF15 is produced when cells are under stress or become damaged.
Levels of this protein naturally rise with age, but they can also increase because of inflammation, heart disease, metabolic disorders, and other health problems. Scientists wanted to know whether GDF15 could also provide an early warning sign for dementia.
To answer this question, the research team analyzed data from more than half a million people who were followed for 15 to 25 years. Participants came from several countries, including the United States, the United Kingdom, Iceland, and Japan.
Blood samples were collected long before most participants developed dementia, allowing the researchers to study whether GDF15 levels could predict future disease.
The findings were striking. People with higher levels of GDF15 before the age of 55 were much more likely to develop dementia later in life than people with lower levels.
The association was especially strong for vascular dementia, a type of dementia caused by reduced blood flow to the brain. The connection with Alzheimer’s disease was present but was weaker than the link with vascular dementia.
The scientists also looked beyond blood tests. Brain scans showed that people with higher GDF15 levels were more likely to have brain shrinkage and damage to the brain’s small blood vessels, even while their memory and thinking remained normal. This suggests that harmful changes may already be occurring long before symptoms become noticeable.
To better understand why GDF15 is linked to dementia, the researchers performed laboratory experiments using human immune cells. They found that the protein changed the way these cells produced energy and also weakened their normal response to viruses.
These discoveries suggest that GDF15 may not simply be a warning sign but could also play a role in the biological processes that contribute to brain disease.
The results are exciting because blood tests are much simpler, cheaper, and less invasive than brain scans or spinal fluid tests. If future studies confirm these findings, doctors may eventually be able to identify high-risk individuals decades before dementia develops.
Early identification could encourage healthier lifestyles, closer medical monitoring, and future preventive treatments when they become available.
The researchers also caution that this study does not prove GDF15 causes dementia. It shows a strong association, but more research is needed to confirm how the protein contributes to disease and whether measuring it improves patient care.
Future studies will need to include more diverse populations before the test becomes part of routine healthcare.
Overall, this study represents an important advance in dementia research. It suggests that a simple blood protein could help reveal hidden brain changes many years before memory loss begins. Although more work remains, the findings offer hope that earlier detection may eventually lead to earlier treatment and better protection of brain health.
If you care about brain health, please read studies about inflammation that may actually slow down cognitive decline in older people, and low vitamin D may speed up cognitive decline.
For more health information, please see recent studies about common exercises that could protect against cognitive decline, and results showing that this MIND diet may protect your cognitive function, prevent dementia.
