Key change to urine could be early warning sign of dementia, researchers say

Foamy urine may be an early warning sign for dementia, raising risk by up to almost 40 per cent, researchers have found.

The symptom, which can make people go to the toilet more often, may indicate high levels of albumin – a protein that leaks into urine when kidney filters are damaged.

Swedish researchers tracked 130,000 adults in Stockholm aged over 65 with no dementia at the start of the study. Over a follow-up of four years, seven per cent developed the condition.

After taking kidney function and other factors into account, scientists at the Karolinska Institute found that people with moderate albumin levels (30–299 mg/g) in their urine had a 25 per cent higher dementia risk.

Those with high levels (more than 300 mg/g) faced a 37 per cent higher risk compared with people showing normal levels (up to 30 mg/g).

The association was strongest for vascular dementia, the second most common form after Alzheimer’s disease and mixed dementia. Vascular dementia occurs when blood flow to the brain is reduced.

Experts said the findings show that problems in other parts of the body, such as the kidneys, can also affect the brain and increase dementia risk.

Dr Hong Xu, assistant professor in neurobiology at the institute, said: “The kidneys and the brain may seem like very different organs, but they share an important characteristic: both depend on a delicate network of small blood vessels.

“When the blood vessels in the kidneys are damaged, the same process often occurs in the brain.”

She added: “These results underscore the importance of routine screening for albuminuria as part of early dementia risk assessment, especially in patients with high blood pressure, diabetes, cardiovascular disease, or kidney disease.

“Early detection of albuminuria could potentially delay or prevent the onset of dementia.”

Not everyone with albuminuria – the medical term for excess albumin in urine – experiences symptoms, according to the National Kidney Foundation.

When symptoms do appear, they can include foamy urine, frequent urination, puffy eyes and swelling in the feet, ankles, belly or face.

Healthy kidneys normally filter albumin to stop it leaking into urine. Kidney damage, however, allows the protein to pass through.

A urine test remains the most effective way to diagnose albuminuria.

Experts particularly urge those at higher risk of albuminuria or kidney disease to have regular check-ups.

The researchers wrote: “Our statistical data suggest that increased albuminuria is associated with a higher risk of all-cause dementia, particularly vascular and mixed dementia.

Early detection of albuminuria may enable more proactive management of kidney health and cognitive function, potentially delaying or preventing the onset of dementia.

Memory problems, thinking and reasoning difficulties, and language problems are common early dementia symptoms, which then worsen over time.

Alzheimer’s Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country’s biggest killer.