Kidney Biomarkers May Help Identify Older Adults’ Risk for Cognitive and Physical Decline
The aging process is often accompanied by declines in both cognitive function and physical ability. New research suggests a strong link between kidney health and these age-related changes, even before the development of overt kidney disease. A study conducted by Aman Shrestha, MGS, MA, and colleagues investigated how specific biomarkers related to kidney function correlate with simultaneous declines in cognitive and physical health in older adults.
Understanding the Connection
Researchers have long observed that chronic kidney disease appears to accelerate aging. However, less was known about the specific role of kidney health in the broader context of age-related decline. As co-author Michelle Shardell, PhD, explained, the study focused on cognitive and physical performance because “most older adults prioritize maintaining independent living.”
How the Study Worked
The study followed 1,902 participants in the Health, Aging, and Body Composition Study. Physical performance was evaluated using 20-meter gait speed measurements taken over ten years, while cognitive performance was assessed using the modified Mini-Mental State score. Researchers analyzed several renal-related biomarkers, including estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio (UACR), and others, in relation to changes in cognitive and physical abilities.
Key Findings
Participants were categorized into three groups based on their cognitive and physical performance trajectories: those with consistently high performance (group 1, n=660), those with sustained cognition but declining gait (group 2, n=744), and those with declining performance in both areas (group 3, n=498). The analysis revealed significant associations between certain kidney biomarkers and these trajectories.
Specifically, each 10 mL/min/1.73 m2 increase in eGFR was associated with a 16% lower odds of being in the group with the steepest declines (group 3) compared to the highest-performing group (group 1). Conversely, a doubling of the urine albumin-to-creatinine ratio (UACR) was linked to a 13% higher chance of being in group 2 and a 23% higher chance of being in group 3.
Further analysis showed that lower levels of alpha-klotho and higher levels of fibroblast growth factor 23 (FGF23) were also associated with accelerated declines in both cognitive and physical function. Adding these biomarkers to the analysis slightly improved the ability to predict these declines.
What Could Happen Next
These findings could lead to the development of new screening tools to identify individuals at risk for accelerated aging. If routinely measured kidney function biomarkers, along with newer biomarkers like alpha-klotho and FGF23, prove effective at predicting decline, they could be incorporated into routine health assessments for older adults. Further research may explore interventions targeting kidney health to potentially preserve cognitive and physical function. It’s also possible that studies will focus on understanding the underlying mechanisms linking kidney health to brain and muscle function.
Frequently Asked Questions
What biomarkers were examined in the study?
The study examined estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio (UACR), serum 25-hydroxyvitamin D, plasma intact parathyroid hormone (iPTH), plasma alpha-klotho, serum intact fibroblast growth factor 23 (FGF23), and vitamin D metabolites.
How were participants grouped for the study?
Participants were divided into three groups based on their cognitive and physical performance trajectories: superior performance, sustained cognition with declining gait, and declining performance in both areas.
What did the researchers find regarding eGFR and UACR?
Higher eGFR levels were associated with lower odds of being in the group with the steepest declines, while higher UACR levels were associated with higher odds of being in the groups experiencing more significant declines.
As we learn more about the connections between kidney health and overall well-being, what lifestyle changes do you think could be most impactful for maintaining cognitive and physical function as we age?