A new study suggests that kidney health is linked to biological markers of dementia. More than 37 million Americans with chronic kidney disease may be at higher risk of developing dementia, reports Scientists in Sweden found that older people who were neurologically healthy, with poorer kidney function, had a higher risk of developing dementia over time.
However, research has shown that deterioration of kidney function alone does not cause dementia. Rather, it acts like strong accelerator in people who already have early signs of brain damage in their blood, especially elevated levels of proteins associated with Alzheimer’s disease, which affects nearly seven million Americans.
In these people, poor kidney function almost doubled the risk of dementia, suggesting that it may accelerate the course of the disease in an already vulnerable brain. “These results show that clinicians should consider kidney health when evaluating Alzheimer’s biomarkers in the blood,” said Dr. Francesca Gasparini.
The scientists also took into account the presence of the gene APOE4which significantly increases the risk of dementia. However, they found that kidney health was a strong independent risk factor, even in people without a genetic predisposition.
When the kidneys fail, toxins and inflammatory substances build up in the blood. Such an environment can damage brain cells and promote the development of dementia. Chronic diseases and older age, which are common in patients with kidney disease, too often lead to changes in the brain, which may explain the higher levels of biomarkers of brain damage.
The researchers followed 2,279 Swedish adults with an average age of 72 who had no signs of dementia at baseline. Participants were enrolled between 2000 and 2004 and followed for approximately eight years. About 30% carried the APOE4 gene.
During the study, which lasted until 2019, the researchers regularly checked kidney function and measured protein levels associated with Alzheimer’s disease using sensitive technology capable of detecting even minimal amounts.
Of 1,722 people with healthy kidneys, 221 developed dementia. Of 557 people with poor kidney function, 141 developed dementia. Although more people with healthy kidneys became ill overall, percentage wise, dementia appeared more often in those with poor kidney function.
The study showed that poor kidney function alone does not cause new cases of dementia. However, it acts as accelerator in people who already have elevated protein levels:
- yes – associated with Alzheimer’s “balls”
- NfL (neurofilament light chain) – means damage and death of brain cells
- GFAP (glial fibrillary acidic protein) – shows inflammation of the brain
The most important risk indicator was the NfL level. People with bad kidneys and high levels of NfL had almost double the risk of dementia compared to those who had healthy kidneys.
“When evaluating these biomarkers in For older adults, monitoring kidney health is more important than many people think. It can help doctors better predict who is at risk of developing the disease more quickly. Why do kidney diseases affect the brain?” added Doctor Gasparini.
Scientists propose two main theories: Failing kidneys are unable to filter proteins from the blood, causing them to build up. Chronic kidney disease causes toxins and inflammation throughout the body that damage the brain and release other proteins that signal damage.
In addition, people with poor kidney function were generally older and had more chronic diseases, which themselves can cause hidden brain damage. The combination of these factors creates a “perfect storm” that accelerates the path to dementia.
