Does serum uric acid act as a modulator of cerebrospinal fluid Alzheimer's disease biomarker related cognitive decline?

Abstract

BACKGROUND AND PURPOSE: The association of serum uric acid, cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) and longitudinal cognitive decline was evaluated using the AD Neuroimaging Initiative database.

METHODS: In 271 healthy subjects, 596 mild cognitive impairment patients and 197 AD patients, serum uric acid and CSF AD biomarkers were measured at baseline, and Mini-Mental State Examination and AD Assessment Scale - Cognitive Subscale (ADAS-cog) were assessed serially (mean duration, 2.9 years). The effect of uric acid on longitudinal cognitive decline was evaluated using linear mixed effect models for Mini-Mental State Examination and ADAS-cog scores in female and male subjects separately, with possible confounders controlled (model 1). To determine the effects of uric acid independent of CSF biomarker (Aβ1-42 or tau) and to test whether the detrimental effects of CSF biomarker differ according to uric acid, CSF biomarker and its interaction with uric acid were further included in model 1 (model 2).

RESULTS: Higher levels of uric acid were associated with slower cognitive decline, particularly in the mild cognitive impairment and dementia subgroups, and more prominently in female subjects. Model 2 with CSF Aβ1-42 showed that higher levels of uric acid were associated with a slower cognitive decline and alleviated the detrimental effect of Aβ1-42 on cognitive decline. Model 2 with CSF tau showed that higher levels of uric acid alleviated the detrimental effect of tau on cognitive decline in female subjects but not in male subjects.

CONCLUSION: Higher levels of uric acid had protective effects on longitudinal cognitive decline independent of and interactively with CSF AD biomarkers.