Low‐Dose Aspirin Use and Cognitive Function in Older Age: A Systematic Review and Meta‐analysis

<jats:sec><jats:title>Objectives</jats:title><jats:p>To investigate whether low‐dose aspirin (&lt;300 mg/d) can influence the onset of cognitive impairment or dementia in observational studies and improve cognitive test scores in randomized controlled trials (<jats:styled-content style="fixed-case">RCT</jats:styled-content>s) in participants without dementia.</jats:p></jats:sec><jats:sec><jats:title>Design</jats:title><jats:p>Systematic review and meta‐analysis.</jats:p></jats:sec><jats:sec><jats:title>Setting</jats:title><jats:p>Observational and interventional studies.</jats:p></jats:sec><jats:sec><jats:title>Participants</jats:title><jats:p>Individuals with no dementia or cognitive impairment initially.</jats:p></jats:sec><jats:sec><jats:title>Measurements</jats:title><jats:p>Odds ratios (<jats:styled-content style="fixed-case">OR</jats:styled-content>s) and 95% confidence intervals (<jats:styled-content style="fixed-case">CI</jats:styled-content>s), adjusted for the maximum number of covariates from each study, were used to summarize data on the incidence of dementia and cognitive impairment in observational studies. Standardized mean differences (<jats:styled-content style="fixed-case">SMD</jats:styled-content>s) were used for cognitive test scores in <jats:styled-content style="fixed-case">RCT</jats:styled-content>s.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Of 2,341 potentially eligible articles, eight studies were included and provided data for 36,196 participants without dementia or cognitive impairment at baseline (mean age 66, 63% female). After adjusting for a median of three potential confounders over a median follow‐up period of 6 years, chronic use of low‐dose aspirin was not associated with onset of dementia or cognitive impairment (5 studies, N = 26,159; <jats:styled-content style="fixed-case">OR</jats:styled-content> = 0.82, 95% <jats:styled-content style="fixed-case">CI</jats:styled-content> = 0.55–1.22, <jats:italic>P</jats:italic> = .33, I<jats:sup>2</jats:sup> = 67%). In three <jats:styled-content style="fixed-case">RCT</jats:styled-content>s (N = 10,037; median follow‐up 5 years), the use of low‐dose aspirin was not associated with significantly better global cognition (<jats:styled-content style="fixed-case">SMD</jats:styled-content>=0.005, 95% <jats:styled-content style="fixed-case">CI</jats:styled-content>=–0.04–0.05, <jats:italic>P</jats:italic> = .84, I<jats:sup>2</jats:sup> = 0%) in individuals without dementia. Adherence was lower in participants taking aspirin than in controls, and the incidence of adverse events was higher.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>This review found no evidence that low‐dose aspirin buffers against cognitive decline or dementia or improves cognitive test scores in <jats:styled-content style="fixed-case">RCT</jats:styled-content>s.</jats:p></jats:sec>