The association between kidney function and cognitive decline in community-dwelling, elderly Japanese people

The aim of this study was to evaluate the relationship between chronic kidney disease (CKD) and cognitive decline in community-dwelling older adults without dementia.

Cross-sectional.

Obu Study of Health Promotion for the Elderly in Japan.

The participants were 4686 residents (community-dwelling older adults without dementia) who completed baseline assessments.

The estimated glomerular filtration rate (eGFR, mL/min/1.73 m(2)) was determined according to the creatinine level, and participants were classified into three mutually exclusive categories: normal (≥60.0 mL/min/1.73 m(2)), mild CKD (45.0-59.9 mL/min/1.73 m(2)), or moderate to severe CKD (<45.0 mL/min/1.73 m(2)). Cognitive function was assessed using the National Center for Geriatrics and Gerontology-Functional Assessment Tool. Multivariate logistic regression was used to examine the relationships between eGFR and cognitive decline.

After multivariate adjustment, participants with lower eGFR had lower cognitive function scores on most domains (P < .05). In particular, participants with advanced CKD (eGFR <45 mL/min/1.73 m(2)) were more likely to have significant cognitive decline on the Trail Making Test part A (odds ratio = 2.347, 95% confidence interval = 1.525-3.614) and the Symbol Digit Substitution Task (odds ratio = 2.308, 95% confidence interval = 1.486-3.585) than those with normal and mild CKD.

A lower level of kidney function was associated with lower cognitive performance in attention and processing speed. These results suggest that eGFR might be an effective method to screen for cognitive decline in community-dwelling older adults.