Association of Kidney Function With Dementia and Structural Brain Differences: A Large Population-Based Cohort Study

Area of Science:

• Nephrology
• Neurology
• Gerontology

Background:

• The relationship between kidney function and dementia risk is not well understood.
• Mechanisms linking kidney health to cognitive decline require further investigation.

Purpose of the Study:

• To investigate the association between estimated glomerular filtration rate (eGFR) and dementia risk.
• To explore the impact of kidney function on dementia onset and brain structure.

Main Methods:

• A longitudinal study of 191,970 dementia-free participants aged ≥60 from the UK Biobank.
• Kidney function assessed via serum creatinine and Cystatin C to calculate eGFR, categorized into normal, mildly impaired, and moderately to severely impaired.
• Dementia incidence tracked over 16 years; brain MRI performed on a subsample to measure brain volumes and white matter hyperintensities.

Main Results:

• Moderate to severe kidney impairment (eGFR < 60) was associated with a 53% increased dementia risk (HR=1.53, 95% CI: 1.32-1.76).
• Dementia onset occurred 1.53 years earlier in individuals with moderate to severe kidney impairment compared to those with normal function.
• Moderate to severe kidney impairment correlated with reduced gray matter volume (β = -0.11, 95% CI: -0.19 to -0.03).

Conclusions:

• Impaired kidney function, particularly moderate to severe impairment, significantly elevates dementia risk and accelerates its onset.
• Brain neurodegeneration, indicated by reduced gray matter volume, may be a key mechanism linking impaired kidney function to dementia.
• These findings highlight the importance of kidney health in maintaining cognitive function and preventing dementia.