Renal function and long-term decline in cognitive function: the Baltimore Longitudinal Study of Aging.

Area of Science:

• Gerontology
• Nephrology
• Neuroscience

Background:

• Renal disease is a known risk factor for dementia and cognitive impairment.
• The specific impact of reduced kidney function on cognitive decline in non-demented individuals is not well understood.

Purpose of the Study:

• To investigate the association between declining renal function and long-term changes in specific cognitive domains.
• To examine cognitive decline in community-dwelling, non-demented adults.

Main Methods:

• Longitudinal study of 2,116 participants from the Baltimore Longitudinal Study of Aging.
• Renal function estimated using serum creatinine and estimated glomerular filtration rate (eGFR).
• Cognitive function assessed using 6 tests over 2-year intervals; analyzed with mixed-effects regression models.

Main Results:

• Increased creatinine levels correlated with faster decline in verbal learning (California Verbal Learning Test) and visual memory (Benton Visual Retention Test).
• Lower eGFR also associated with accelerated decline in verbal memory.
• Findings were consistent after adjusting for age, sex, race, and comorbidities.

Conclusions:

• Reduced kidney function is an independent predictor of greater long-term decline in visual and verbal memory and learning.
• Maintaining kidney health may be crucial for preserving cognitive function in aging populations.