A simple urine test could reveal your risk of developing dementia decades before symptoms appear, a new study shows. For the study, my colleagues and I tracked 130,000 people and found that protein in the urine may act as an early warning sign for memory problems.
Author
- Hong Xu
Assistant Professor at Division of Clinical Geriatrics, Karolinska Institutet
Our research showed that people with higher levels of protein leaking into their urine - a condition known as albuminuria - had a significantly greater chance of developing dementia . The association was strongest for vascular dementia, the second most common form after Alzheimer's, and mixed dementia, which combines features of both types.
Crucially, this connection held true regardless of how well participants' kidneys were functioning overall. In other words, protein in urine appears to predict dementia risk independently, even when standard kidney tests appear normal.
Our findings highlight how closely the kidneys and brain are connected. Both rely on networks of tiny, delicate blood vessels to function properly. When these vessels are damaged - by high blood pressure, diabetes, or other factors - the same damage that causes protein to leak into urine can also reduce blood flow to the brain.
Your kidneys act like filters, keeping useful proteins in your blood while filtering out waste. When those filters are damaged, albumin protein starts leaking through .
The brain has its own protective barrier - the blood-brain barrier - made of tightly packed cells that prevent harmful substances from entering brain tissue. Just as damaged kidney filters become leaky, a compromised blood-brain barrier allows toxins and inflammatory molecules to pass through, potentially triggering the brain changes that lead to dementia.
This discovery opens exciting possibilities for prevention. Several medications already used to protect kidneys may also protect memory. Ace inhibitors and Arbs , blood pressure drugs that reduce protein leakage, could potentially do double duty for brain health.
Even newer drugs show promise. GLP-1 drugs such as semaglutide (better known as Ozempic) and SGLT2 inhibitors such as dapagliflozin were originally developed for diabetes but also reduce protein in urine. Whether they prevent dementia remains to be proved, but early signs are encouraging.
While we cannot yet prove that treating kidney problems will prevent dementia - that would require following participants for decades in controlled trials - the biological pathway makes sense, particularly given how blood vessel damage affects both organs.
An ounce of prevention
So when should you start caring about this? Vascular damage accumulates over years, so earlier intervention is better. For most people, focusing on kidney and heart health from middle age onwards is sensible, especially if you have diabetes, high blood pressure, kidney disease, obesity, or a family history of these conditions.
Currently, doctors mainly test urine protein in people with diabetes or high blood pressure. But our findings raise questions about whether everyone over 50 should be screened, particularly those with multiple risk factors. That is a public health question requiring more research and policy discussion.
The good news is that you do not need to wait for new guidelines to take action. Lifestyle changes that protect kidneys also benefit the brain. Quitting smoking, controlling blood pressure and blood sugar, eating a balanced diet and exercising regularly can reduce your risk of both kidney disease and dementia.
If confirmed by future studies, urine protein testing could become a standard part of dementia risk assessments. It is cheap, non-invasive and can be performed with simple dipstick tests in any doctor's office.
While there is still no cure for dementia, early detection and prevention remain our best tools. By recognising that protein in urine signals more than just kidney trouble, we may be able to identify and protect those at risk long before memory problems begin. Sometimes the most important clues about your brain's future health are found in the most unlikely places.
Hong Xu receives funding from the Swedish Research Council .
