By Chris Berrie
VIENNA -- March 12, 2013 -- Hyperuricaemia (gout) is related to white-matter atrophy and worse cognition in the general population, according to research presented at the 25th Annual European Congress of Radiology (ECR).
Dementia is preceded by a long preclinical course where brain damage accumulates and cognitive decline occurs, explained Benjamin F. J. Verhaaren, MD, Erasmus MC University Medical Centre, Rotterdam, Netherlands, speaking at a presentation here on March 8. High serum uric-acid levels have recently been associated with focal vascular brain disease, but it is not known how hyperuricaemia relates to brain atrophy.
The current population-based study was designed to determine whether high uric-acid levels are associated with brain atrophy and worse cognition.
The investigation comprised 814 subjects from the Rotterdam Scan Study (mean age, 62 years; female, 50.9%) who were known to be free of dementia and cortical infarcts. Baseline serum uric-acid levels were measured, providing a mean measurement of 342 micromol/L for males and 281 micromol/L for females.
Five different uric-acid levels were correlated with brain atrophy and cognition, with the highest levels defined as hyperuricaemia at >420 micromol/L and >360 micromol/L, respectively. Associations were determined as “effect estimates” and defined as differences in Z scores per standard deviation increase in uric acid.
Damage to white matter can be seen as focal lesions on magnetic resonance imaging (MRI). Each subject underwent MRI at baseline and at 5 years follow-up, to define white- and grey-matter atrophy.
Decreases in white-matter volume were significantly associated with hyperuricaemia. Overall, there was a -0.03 (95% confidence interval [CI], -0.05 to 0.00) association effect for total brain volume, based on white matter (-0.07; 95% CI, -0.12 to -0.01) rather than grey matter (0.03; non-significant).
At the same time, the subjects underwent cognition testing to provide compound scores of their main cognitive domains. This demonstrated a significant -0.08 (95% CI, -0.14 to -0.03) association effect for global cognition. With no significant effects seen for memory (-0.07), the association effect was mainly affected by executive function (-0.09; 95% CI, -0.15 to -0.03) and information processing speed (-0.09; 95% CI, -0.16 to -0.03).
Decreases in executive function and information processing speed were significantly associated with hyperuricaemia
These effects were independent of a range of cardiovascular risk factors, including blood pressure, cholesterol levels, alcohol use, kidney function and smoking.
“Uric acid can cause oxidative stress, so it can be toxic to the brain, and…it is associated with vascular health, so it can also act on the vessels, which can also cause damage to the brain,” Dr. Verhaaren concluded
[Presentation title: The Relation of Uric Acid to Brain Atrophy and Cognition: the Rotterdam Scan Study. Abstract B-0402]
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