Risk of dementia, especially vascular or mixed dementia, may be increased in elderly people with high serum uric acid (SUA) levels, a study found.
Researchers assessed the longitudinal association between SUA level and incident dementia using a French population-based cohort study of 4,931 non-institutionalized people at least 65 years of age who were randomly selected from electoral rolls. Researchers also looked at the relation between SUA level and MRI markers of brain aging (white matter hyperintensity volume, lacunes, and hippocampal volume). Results were published early online by the Annals of the Rheumatic Diseases on July 28.
The study sample of 1,598 people (mean age, 72.4; 38.3% men) had 13,357 person-years of follow-up (median duration, 10.1 years). Dementia developed in 110 participants (crude incidence rate, 8.2/1,000 person-years).
Risk of dementia was increased in participants in the highest quartile of SUA level (≥345 μmol/L for men, ≥292 μmol/L for women) versus the lowest quartile (<260 μmol/L for men, <209 μmol/L for women) (hazard ratio [HR], 1.90; 95% CI, 1.10 to 3.29; P=0.008 for trend). The association persisted after adjustment for traditional cardiovascular risk factors (HR, 2.2; 95% CI, 1.21 to 3.98; P=0.004 for trend) and with further adjustment for NSAIDs or drugs affecting SUA level (HR, 2.21; 95% CI, 1.22 to 4.00; P=0.004 for trend) or inflammatory markers (HR, 2.43; 95% CI, 1.34 to 4.42; P=0.001 for trend).
The association with SUA level was stronger with vascular or mixed dementia (HR, 6.41; 95% CI, 1.20 to 34.29; P for trend=0.022) than Alzheimer's disease (HR, 1.89; 95% CI, 0.94 to 3.83; P for trend=0.06). There was no association between SUA levels and MRI markers of cerebrovascular disease or hippocampal volume for SUA level at or above the 75th percentile.
The association between SUA level and vascular or mixed dementia might be affected by interim strokes, the authors said. “Brain infarcts and lacunes were not associated with SUA levels in our study,” the authors wrote. “However, the association between SUA levels and vascular or mixed dementia, but not all dementia, disappeared after adjustment on interim strokes, suggesting a mediating effect of stroke for the vascular or mixed dementia subtype only.”