A new Canadian study has found that chronic kidney disease (CKD) is linked to lower cognitive performance, affecting reasoning, memory, and reaction time.
The research, published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, suggests that impaired kidney function may also contribute to brain atrophy, potentially increasing the risk of neurodegenerative diseases like Alzheimer’s.
The study, led by Dr. Shady Rahayel, a neuropsychologist at Université de Montréal, examined data from approximately 16,000 healthy adults.
Researchers measured participants’ glomerular filtration rate (GFR)—a key indicator of how well the kidneys filter waste from the blood—and compared it to their cognitive abilities.
The findings showed that people with weaker kidney function performed worse on cognitive tests, regardless of factors like age, sex, education, weight, or cardiovascular health.
Brain scans also revealed shrinkage in the cerebral cortex, particularly in the frontal lobes, which are involved in decision-making, memory, and problem-solving.
Scientists are still trying to understand exactly why kidney disease is linked to cognitive decline, but several possible explanations exist:
- Toxin Buildup – When kidneys fail to properly filter waste, harmful substances may accumulate in the blood, potentially affecting brain function.
- Vascular Damage – Diabetes, the leading cause of kidney disease, damages blood vessels throughout the body, including in the brain. However, the study found that kidney-related cognitive decline persists even when vascular problems are accounted for, suggesting other mechanisms are at play.
- Brain Atrophy – Using advanced brain imaging, researchers measured the thickness of the cerebral cortex in 50,000 locations and found a direct link between kidney function and brain shrinkage. Since brain atrophy is associated with dementia and neurodegeneration, this connection raises concerns about long-term cognitive health.
What This Means for Future Research
Dr. Rahayel believes that understanding which brain regions are most affected by kidney function could lead to new treatments and early interventions for cognitive decline. If future studies confirm these findings, doctors might be able to screen people with kidney problems for cognitive risks earlier and develop targeted therapies to slow down brain degeneration.
This research highlights the importance of kidney health not just for the body, but also for the brain. Taking steps to protect kidney function—such as managing blood sugar, controlling blood pressure, and staying hydrated—may also help safeguard cognitive health in the long run.
If you care about kidney health, please read studies about how to protect your kidneys from diabetes, and drinking coffee could help reduce risk of kidney injury.
For more information about kidney health, please see recent studies about foods that may prevent recurrence of kidney stones, and eating nuts linked to lower risk of chronic kidney disease and death.
The research findings can be found in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.
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