High uric acid levels linked to cognitive deficits

NEW YORK, Jan 17 (Reuters) Older adults with high-normal levels of uric acid are significantly more likely than those with low-moderate concentrations to experience mild cognitive impairment (loss of memory), according to results of a study published in the medical journal Neuropsychology.

''Among possible markers of age-related cognitive decline, uric acid is controversial,'' Dr David J Schretlen, of Johns Hopkins University Hospital, Baltimore, and colleagues note. On one hand, uric acid has antioxidant properties, which inhibits cell damage, while on the other hand, it is often elevated in diseases that frequently lead to cognitive impairment.

The researchers studied 96 community-dwelling adults between the ages of 65 and 92 years who underwent physical and neurological examinations, psychiatric interviews, laboratory blood studies, MRI brain scans, and neuropsychological testing.

Blood levels of uric acid among the women ranged from 1.5 to 7.1 mg/dL. For men, levels ranged from 1.5 to 7.6 mg/dL.

Subjects with mildly elevated (but normal) uric acid - greater than 5.8 mg/dL for men or greater than 4.8 mg/dL for women -- were significantly more likely to have a below-average performance on cognitive measures. This included having nearly 6-times the likelihood impaired processing speed; 3.5-times for working memory; and 2.7 times for verbal learning and memory.

After the researchers corrected the data for possible overestimation by adding in the potential effects of age, sex, race, years of education, and self-reported hypertension, diabetes, smoking, and history of alcohol abuse or dependence, they found that high blood levels of uric acid ''remained associated with increased risk of below average performance on measures of working memory (4.25-times) and verbal learning/memory (5.02-times),'' Schretlen's team reports.

They suggest these findings might justify a clinical trial of an agent that blocks xanthine oxidase, an enzyme involved in uric acid formation, to see if it improves cognitive performance in elderly people with high uric acid levels.

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