A major new study from Sweden suggests that a simple urine test may help identify people at higher risk of developing dementia years before symptoms appear.
Researchers found that people with higher levels of a protein called albumin in their urine were significantly more likely to develop dementia later in life.
The research was led by scientists at Karolinska Institutet and published in the Journal of Internal Medicine. The findings add to growing evidence that brain health is closely connected to the health of other organs in the body, especially the kidneys and blood vessels.
Dementia is one of the world’s fastest-growing health problems. Millions of people currently live with dementia, and experts expect the number to rise sharply as populations age.
Dementia affects memory, thinking, language, decision-making, and daily functioning. Alzheimer’s disease is the most common form, but there are several different types of dementia.
Although aging remains the strongest risk factor, scientists now believe many other health conditions may also influence dementia risk. High blood pressure, diabetes, obesity, heart disease, and poor circulation have all been linked to problems in brain health.
The new study focused on albumin, a protein that normally stays inside the bloodstream. Healthy kidneys filter waste from the blood while keeping important substances like albumin inside the body.
When albumin begins leaking into urine, it often signals that the kidneys are damaged or not functioning properly. This condition is called albuminuria.
Researchers believe albuminuria may act as an early warning sign of damage to small blood vessels throughout the body.
To investigate the connection, the scientists followed about 130,000 adults in Stockholm who were all over the age of 65 and did not have dementia at the beginning of the study.
Over an average follow-up period of around four years, approximately 7% of participants developed some form of dementia.
The researchers carefully analyzed urine test results and compared dementia risk among people with different albumin levels.
After adjusting for other medical conditions and health factors, they found that people with moderate albumin levels in their urine had a 25% higher risk of developing dementia compared with those with normal levels.
People with high levels of albuminuria faced an even greater risk. Their chances of developing dementia were about 37% higher.
The increased risk was especially noticeable for vascular dementia and mixed dementia.
Vascular dementia develops when blood flow to the brain becomes reduced or blocked. It is often linked to strokes, high blood pressure, diabetes, and blood vessel disease. Mixed dementia refers to a combination of vascular dementia and Alzheimer’s disease.
The researchers believe the findings may be explained by similarities between the kidneys and the brain.
Both organs rely heavily on tiny, delicate blood vessels to function properly. Damage to these small blood vessels in the kidneys may reflect similar damage happening inside the brain.
One important part of this process involves the blood-brain barrier. This protective barrier acts like a filter between the bloodstream and the brain. Under healthy conditions, it prevents harmful substances, toxins, and inflammatory molecules from entering brain tissue.
However, when blood vessels become damaged, the blood-brain barrier may become weaker and more “leaky.” This can allow harmful substances to enter the brain and trigger inflammation.
Researchers believe long-term inflammation and blood vessel damage may gradually injure brain cells and contribute to dementia development.
Lead researcher Hong Xu said the findings highlight the importance of screening people for albuminuria, especially those with high blood pressure, diabetes, kidney disease, or heart disease.
Because urine testing is simple and widely available, researchers believe it may become a useful tool for identifying people who need closer monitoring for dementia risk.
The study is considered one of the largest of its kind, which strengthens confidence in the findings. By following a very large group of older adults, the researchers were able to observe meaningful patterns linking kidney health and dementia.
However, the scientists also caution that the study does not prove albuminuria directly causes dementia. Instead, the findings show a strong association between the two conditions.
More research will still be needed to understand exactly how kidney damage, blood vessel health, and brain disease interact over time.
Even so, the study adds to a growing body of evidence suggesting that protecting heart and kidney health may also help protect the brain.
Doctors already encourage people to control blood pressure, manage diabetes, avoid smoking, exercise regularly, maintain a healthy weight, and eat a balanced diet to reduce cardiovascular risk. These same healthy habits may also reduce the risk of dementia.
The findings are especially important because dementia often develops slowly over many years before symptoms become obvious. Identifying people at higher risk earlier may give doctors more opportunities to slow or delay disease progression.
The research also highlights how connected the body’s systems truly are. Problems that first appear in the kidneys may offer important clues about what is happening in the brain long before memory problems begin.
Scientists hope future studies will determine whether treating albuminuria or protecting small blood vessels more aggressively could help lower dementia risk in older adults.
For now, the findings provide another reminder that maintaining healthy blood vessels and healthy kidneys may be an important part of protecting long-term brain health.
If you care about dementia, please read studies about how the Mediterranean diet could protect your brain health, and Vitamin B supplements could help reduce dementia risk.
For more health information, please see recent studies that high-fiber diet could help lower the dementia risk, and these antioxidants could help reduce dementia risk.
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