A major new study has found that people living with advancing chronic kidney disease (CKD) are more likely to experience declines in cognitive function, including difficulties with attention, processing speed and executive thinking.
The research, published in The Journal of the American Medical Association (JAMA) Network Open, suggests that the severity of kidney dysfunction may itself be a risk factor for cognitive impairment rather than being entirely explained by age or other co-existing conditions.
Chronic kidney disease is defined by a sustained reduction in kidney function that lasts for at least three months and can lead to progressively poorer ability to filter toxins and waste from the blood. In the latest study, scientists tracked more than 5,600 adults aged between 21 and 79 for roughly six years, combining laboratory measures of kidney health with standardized tests of cognitive performance to assess their mental function over time.
The analysis found that participants with higher levels of protein in the urine—a marker of more pronounced kidney damage—and lower filtration rates tended to perform more poorly on measures of cognition. Each statistically significant increase in proteinuria was linked to a greater likelihood of trouble with attention and speed of information processing as well as executive functions such as planning and decision-making.
Researchers noted that many of the mechanisms responsible for this link are still being explored, but they pointed to several biological and systemic factors that could explain how deteriorating kidney function impacts the brain.
Chronic kidney dysfunction can contribute to high blood pressure, chronic inflammation, disturbances in bone and mineral metabolism, oxidative stress and imbalances in sleep patterns—each of which has previously been implicated in cognitive decline independently of kidney health.
Prior scientific work has also highlighted structural and vascular changes in the brains of people with poor kidney function. Reduced estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio have been tied to brain abnormalities on imaging studies, suggesting that vascular damage and impaired blood flow may underlie part of the cognitive changes seen in CKD patients.
Public health experts say understanding the connection between kidney disease and the brain is crucial because cognitive impairment can worsen quality of life, complicate self-management of chronic conditions, and increase the risk of hospitalisation and mortality. Broader research reviews have also linked cognitive dysfunction in CKD with higher rates of cardiovascular events and stroke, underscoring the need for early detection and integrated care approaches.
The new findings add to a growing body of evidence that kidney health is closely interwoven with neurological outcomes, particularly as the global burden of CKD rises due to ageing populations and increasing prevalence of diabetes and hypertension. Continued research is needed to define causative pathways and develop strategies for protecting brain function in people with kidney disease.
