Low dose aspirin and cognitive function in the women's health study
cognitive cohort

BMJ  2007;334:987 (12 May)

Objective To determine whether low dose aspirin protects women aged 65
or more against cognitive decline.

Design Cohort study within both arms of the women's health study, a
randomised, double blind, placebo controlled trial of low dose aspirin
for the primary prevention of cardiovascular disease and cancer,
1992-5.

Setting Women's health study, 1998-2004.

Participants 6377 women aged 65 or more.

Interventions Low dose aspirin (100 mg on alternate days) or placebo
for a mean of 9.6 years.

Main outcome measures Women had three cognitive assessments at two
year intervals by telephone. The battery to assess cognition included
five tests measuring general cognition, verbal memory, and category
fluency. The primary prespecified outcome was a global score,
averaging performance across all tests. The key secondary outcome was
a verbal memory score, averaging performance on four measures of
verbal memory.

Results At the initial assessment (mean 5.6 years after randomisation)
cognitive performance in the aspirin group was similar to that of the
placebo group (mean difference in global score -0.01, 95% confidence
interval -0.04 to 0.02). Mean decline in the global score from the
first to the final cognitive assessment was also similar in the
aspirin compared with placebo groups (mean difference 0.01, -0.02 to
0.04). The risk of substantial decline (in the worst 10th centile of
decline) was also comparable between the groups (relative risk 0.92,
0.77 to 1.10). Findings were similar for verbal memory; however, a 20%
lower risk was observed for decline in category fluency with aspirin
(relative risk 0.80, 0.67 to 0.97).

Conclusion Long term use of low dose aspirin does not provide overall
benefits for cognition among generally healthy women aged 65 or more.

Here's Journal Watch Women's Health's take on this study:

Studies of cognitive benefit from aspirin and other anti-inflammatory
agents have yielded mixed results. The Women's Health Study was a
large, randomized, placebo-controlled study of vitamin E (600 IU on
alternate days) and low-dose aspirin (100 mg on alternate days) for
the prevention of cardiovascular disease and cancer. In this 4-year
subgroup analysis of approximately 6400 women 65 or older,
investigators administered tests of general cognition and verbal
memory by telephone interview at 2-year intervals to women who had
already received aspirin or placebo for an average of 5.6 years.

Global scores for cognitive function and scores for verbal memory did
not differ between the two groups at initial testing, and the mean
decline in overall cognitive performance was also similar between
groups at each of the two follow-up assessments. The aspirin group
performed better than the placebo group in category fluency (a test of
executive brain function) at all three assessments. In the subsets of
women who were current smokers or who had hyperlipidemia, the aspirin
group experienced significantly less cognitive decline than did the
placebo group.

Comment: In terms of category fluency, the effects of aspirin appeared
to offset age-related decline by the equivalent of about 2.6 years;
however, because only one test was used to assess executive brain
function, the results should be interpreted with caution. In general,
low-dose aspirin did not prevent cognitive decline during a 4-year
period in nonsmoking, nonhyperlipidemic women. In women with known
cardiovascular risk factors, aspirin might prevent some cognitive
decline, but additional long-term studies are needed.

- Wendy S. Biggs, MD