NEW YORK (Reuters Health) - Among healthy older women, low-dose aspirin does little to prevent or delay cognitive decline over the following decade, according to analysis of data from the Women's Health Study.

There has been little published evidence to support the belief that low-dose aspirin therapy can protect against early cognitive decline, thus reducing the risk of dementia and Alzheimer's disease. According to Dr. Jae Hee Kang and colleagues at Brigham and Women's Hospital in Boston, trials to establish this association have yielded inconsistent results.

"Because aspirin protects cardiovascular health, we thought it would also protect against cognitive decline," Dr. Kang told Reuters Health. "We knew that, at the low dose (100 mg every other day) used in this trial, aspirin really can't act as an antiinflammatory agent."

To clarify the effect of aspirin and aging on the ability to think, learn and remember, Dr. Kang's group evaluated a subgroup of 6377 participants in the Women's Health Study. The average age was 72 and subjects were free of cardiovascular disease, cancer, or other major comorbidities at baseline.

The women were randomized to aspirin or placebo, and cognitive status was assessed by telephone approximately 5.6 years later. Assessments were repeated after another 2 and 4 years, for a total mean follow-up of 9.6 years. The investigators report in BMJ Online First that 5073 women completed all three evaluations.

There was very little difference between the aspirin and the placebo groups in results of tests used to analyze different aspects of cognition - immediate or delayed verbal memory, cognitive status, and global score -- even at the final assessment.

The one exception was results for category fluency "Category fluency is a partial measure of executive function," Dr. Kang explained. By the final assessment, test results for fluency showed a 20% less decline in the aspirin group (p = 0.02).

"Physicians should realize that, while low-dose aspirin improves cardiovascular health, they should still weigh the risks and benefits of the drug when treating elderly patients," Dr. Kang concluded. "For women in their 70s, low-dose aspirin will have no effect on their cognitive function."