A new study published in the journal Neurology has found that people with poor kidney function tend to have higher levels of Alzheimer’s-related proteins in their blood.
However, this does not mean they are more likely to develop dementia. The researchers stress that the findings only show a connection, not a cause-and-effect relationship.
The kidneys play a vital role in cleaning the blood. They remove waste and harmful substances, which are then flushed out through urine. When the kidneys are not working well, these substances can build up in the body.
In this study, researchers found that people with weaker kidneys had higher levels of certain proteins linked to Alzheimer’s disease, but they were not more likely to be diagnosed with dementia.
Dr. Francesca Gasparini from the Karolinska Institutet in Stockholm, Sweden, led the study. She explained that while poor kidney function did not raise the risk of dementia on its own, it might speed up the development of dementia in people who already have high levels of Alzheimer’s proteins in their blood.
The study included 2,279 adults who did not have dementia when the study began. Their average age was 72. They took part in medical exams and memory tests, and gave blood samples.
The researchers tested their blood for kidney function and for Alzheimer’s-related biomarkers like tau, amyloid beta, neurofilament light chain (NfL), and glial fibrillary acidic protein.
The participants were followed for an average of eight years. Out of 1,722 people with normal kidney function, 221 developed dementia. Out of 557 people with poor kidney function, 141 developed dementia.
Although people with weaker kidneys had more Alzheimer’s proteins in their blood, they were not more likely to be diagnosed with dementia overall.
However, among people who had both poor kidney function and high levels of the protein NfL, the risk of developing dementia nearly doubled. This suggests that kidney health may affect how quickly dementia develops in people who already show signs of Alzheimer’s disease in their blood.
Dr. Gasparini said this study highlights the importance of considering kidney health when looking at Alzheimer’s blood test results. She believes that checking kidney function may help doctors better understand which patients are at risk for faster disease progression.
The study had some limitations. For example, Alzheimer’s biomarkers were only tested once, so researchers couldn’t see how changes in kidney function over time might affect the results. Also, most of the participants were well-educated and lived in cities in Sweden, so the results may not apply to other groups.
Still, the study offers new insights. While kidney problems don’t seem to increase the chances of getting dementia, they might play a role in how quickly dementia symptoms appear in people already at risk. This could help doctors personalize treatment plans by looking at both brain and kidney health.
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