A new study published in the journal Neurology suggests that people with reduced kidney function tend to show higher levels of Alzheimer's-related proteins in their blood.

However, this does not mean they are more likely to develop dementia. The findings help doctors better understand how kidney health may affect test results for Alzheimer's, and why it's important to consider kidney function when reading these tests.

The kidneys are responsible for filtering waste and toxins from the blood, which are then removed from the body through urine. When kidney function declines, waste products can build up in the bloodstream. This study explored whether this might also apply to Alzheimer's-related proteins that circulate in the blood.

The research was led by Dr. Francesca Gasparini of the Karolinska Institutet in Stockholm, Sweden. Her team studied 2,279 adults who had an average age of 72 and did not have dementia when the study began. Participants completed a variety of tests, including blood tests to measure kidney function and several Alzheimer's biomarkers.

These included proteins commonly linked to Alzheimer's such as tau, amyloid beta, neurofilament light chain, and glial fibrillary acidic protein. Participants also took memory and...

Over about eight years of follow-up, 221 of the 1,722 people with healthy kidney function developed dementia. In comparison, 141 of the 557 people with impaired kidney function developed dementia.

When researchers looked more closely at the data, they found that people with reduced kidney function tended to have higher levels of most of the Alzheimer's biomarkers in their blood. This was true even for participants who didn't develop dementia during the study.

Importantly, after adjusting for age, gender, and a known genetic risk factor for Alzheimer's (called APOE e4), researchers still found no direct link between poor kidney function and an increased risk of developing dementia.

However, the study did find something noteworthy. Among people who already had high levels of a specific brain-related protein called neurofilament light chain, those with reduced kidney function had almost twice the risk of developing dementia compared to people with healthy kidneys.

This suggests that poor kidney function may speed up the appearance of dementia in those who already have biological signs of brain changes.

Dr. Gasparini explained that doctors should pay close attention to kidney health when evaluating Alzheimer's blood tests. Someone with high biomarker levels and poor kidney function might need closer monitoring, as they could be at risk for faster progression of cognitive problems.

The researchers noted a few limitations. For example, they only measured the Alzheimer's biomarkers once, so they couldn't track changes in these levels over time. Also, most participants were well-educated and lived in urban parts of Sweden, which means the findings might not apply to more diverse or rural populations.

Still, this study adds important knowledge to the field. It shows that kidney health can influence Alzheimer's test results, even if it doesn't directly raise the chance of developing the disease.

For doctors, this means that kidney function should be considered when using blood tests to predict Alzheimer's risk or progression. For patients, it's a reminder of how deeply connected our body systems are -- and how taking care of one organ may help protect others.

If you care about Alzheimer's disease, please read studies about vitamin D deficiency linked to Alzheimer's and dementia, and strawberries can be good defence against Alzheimer's.

For more health information, please see recent studies about foods that reduce Alzheimer's risk, and oral cannabis extract may help reduce Alzheimer's symptoms.

Copyright © 2025 Knowridge Science Report. All rights reserved.