Impaired kidneys can raise Alzheimer’s-related proteins in the bloodstream without increasing the overall likelihood of dementia.
But for those with already elevated biomarkers, poor kidney function may accelerate progression.
Kidney Function and Alzheimer’s Biomarkers
People with reduced kidney function tend to show higher concentrations of Alzheimer’s biomarkers in their blood, yet they do not appear to face a greater overall chance of developing dementia. These findings come from a study published December 3, 2025, in Neurology®, the medical journal of the American Academy of Neurology.
The research does not demonstrate that kidney problems directly cause elevated Alzheimer’s biomarkers. Instead, it identifies a relationship between the two.
Kidneys play a central role in clearing waste and toxins from the bloodstream, removing these substances through urine.
Biomarker Levels and the Role of Kidney Health
“Our study found that when the kidneys are not functioning properly, there may be higher levels of Alzheimer’s biomarkers in the blood,” said study author Francesca Gasparini, MD, of Karolinska Institutet in Stockholm, Sweden. “While we did not find that having reduced kidney function increased the risk of developing dementia, we did find that impaired kidney function may accelerate the onset of dementia in people who have higher levels of biomarkers. This highlights the need for doctors to consider kidney function when interpreting results of Alzheimer’s biomarkers in the blood.”
The study followed 2,279 adults with an average age of 72, all of whom were dementia-free at the start. Participants completed medical assessments and cognitive testing. Blood samples were used to evaluate kidney performance and to measure several Alzheimer’s disease biomarkers, including tau, amyloid beta proteins, neurofilament light chain proteins, and glial fibrillary acidic proteins.
Long-Term Tracking of Kidney Function and Dementia
Researchers monitored participants for about eight years. Of the 1,722 individuals with healthy kidney function, 221 were diagnosed with dementia during the study period. Among the 557 participants with impaired kidney function, 141 developed dementia.
The team reported that poorer kidney function was associated with higher levels of most of the Alzheimer’s biomarkers analyzed. Removing participants who developed dementia during the study did not change the pattern of results.
Dementia Risk, Neurofilament Light Chain and APOEe4
After considering age, sex and APOEe4 — a genetic biomarker linked to a higher risk of Alzheimer’s disease — the researchers concluded that reduced kidney function was not tied to a greater likelihood of dementia when compared to normal kidney function.
However, they also found that people with impaired kidney function and elevated levels of neurofilament light chain faced nearly double the risk of dementia compared to participants with preserved kidney function and similarly high biomarker levels. According to Gasparini, this suggests that kidney health might influence when dementia begins in individuals with elevated Alzheimer’s biomarkers, even if it does not alter the overall probability of developing the disease.
Importance of Monitoring Kidney Health
“When looking at these biomarkers in older adults, keeping an eye on kidney health may be more important than one might think,” Gasparini said. “Monitoring kidney health may help clinicians better interpret these biomarkers and identify who might be at risk for faster disease progression.”
Study Limitations
One limitation of the research is that Alzheimer’s-related blood biomarkers were measured only once, making it impossible to determine how changes in kidney function over time might affect biomarker levels. In addition, most participants were highly educated and lived in urban areas of Sweden, which means the findings may not apply in the same way to other groups.
Reference: “Kidney Function, Alzheimer Disease Blood Biomarkers, and Dementia Risk in Community-Dwelling Older Adults” by Francesca Gasparini, Martina Valletta, Davide Liborio Vetrano, Giorgi Beridze, Debora Rizzuto, Amaia Calderón-Larrañaga, Claudia Fredolini, Matilda Dale, Bengt Winblad, Laura Fratiglioni and Giulia Grande, 3 December 2025, Neurology.
DOI: 10.1212/WNL.0000000000214446
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
link
About the Author
