Aspirin and dementia: a 70% lower risk, but only in one genetic subgroup

The full story behind my Short: In the ASPREE trial (13,541 older adults with genetic data), aspirin was linked to lower dementia risk only in the top 20% of a platelet-linked genetic score (1% vs 3.3%), with roughly double the major bleeding (4.4% vs 2.1%).

This is not advice to start taking aspirin. Aspirin raises the risk of serious bleeding. Talk to your doctor before starting or stopping any medicine.

The short version

Monash University researchers re-analysed the ASPREE trial of daily low-dose aspirin in older adults, using genetic data. Overall, aspirin did not lower dementia risk. But in one genetic subgroup, people taking aspirin had much less dementia than those on placebo, and more serious bleeding [1][2].

13,541ASPREE participants with genetic data (older adults)
1% vs 3.3%dementia, aspirin vs placebo, in the top 20% of one genetic score
HR 0.28≈70% lower relative risk in that subgroup (95% CI 0.15–0.52)
4.4% vs 2.1%major bleeding, aspirin vs placebo, same subgroup (HR 2.13)

What they found

ASPREE randomly assigned older adults to daily low-dose aspirin or placebo. The new study screened 1,848 polygenic scores (more than 1,800) to look for groups who might respond differently [1].

One score, linked to platelet count (the paper also describes it in terms of mean platelet volume), stood out. In the top fifth (quintile) of that score, dementia occurred in 1% of people on aspirin vs 3.3% on placebo (hazard ratio 0.28, 95% CI 0.15–0.52), about 70% lower relative risk [1][2]. No benefit was seen in the other quintiles [1].

In the same group, major bleeding was 4.4% on aspirin vs 2.1% on placebo (hazard ratio 2.13, 95% CI 1.36–3.34) [1][2]. The score was not linked to known dementia risk genes [2].

Limits and caveats

  • Subgroup finding. It came from testing many genetic scores, so it could be a chance result. The authors call it hypothesis-generating [1].
  • Needs confirming. It needs validation in other groups and a dedicated trial [1][2].
  • Relative, not absolute. “70% lower” is relative; the absolute difference was about 2.3 percentage points (1% vs 3.3%).
  • Bleeding. Major bleeding roughly doubled in the same group [2].

Watch the Short

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AI voice note: the narration in this Short is my own voice, cloned with AI.

Why it matters

Earlier ASPREE results found no overall dementia benefit from aspirin. This analysis suggests a possible biological lead worth testing, but it does not change advice. In the researchers' words, people shouldn't start taking aspirin to prevent dementia on the basis of this study without consulting their doctor, particularly given the increased risk of serious bleeding [2].

Full narration (transcript)

Aspirin, and 70 percent less dementia? There's a big catch. First: this is not advice to start taking aspirin. It raises the risk of serious bleeding. Talk to your doctor. The data come from ASPREE, a trial of daily low-dose aspirin, with genetic data on more than 13,500 older adults. Overall, aspirin did not lower dementia risk in this trial. The team tested over 1,800 genetic scores. One stood out: a score linked to platelet count, the cells that help blood clot. In the top 20 percent for that score, 1 percent on aspirin got dementia, versus 3.3 percent on placebo. About 70 percent lower relative risk. But major bleeding in that group: 4.4 percent on aspirin, versus 2.1 percent on placebo. Roughly double. It's a subgroup finding the authors call hypothesis-generating. It needs confirming, including in a dedicated trial. So don't start aspirin for dementia because of this study. Speak to your doctor first. Follow the link to the main website for much deeper information.

Sources

  1. [1] Fransquet PD et al. (2026). Alzheimer's & Dementia 22(9). doi:10.1002/alz.71817 (open access, CC BY 4.0). https://doi.org/10.1002/alz.71817
  2. [2] Monash University (2026). Genetic analysis reveals potential benefit of aspirin for reducing dementia risk. https://www.monash.edu/news/articles/genetic-analysis-reveals-potential-benefit-of-aspirin-for-reducing-dementia-risk
  3. [3] ScienceDaily, 24 October 2026. https://www.sciencedaily.com/releases/2026/10/261024222026.htm

Credits

Images via Wikimedia Commons (illustrative unless stated): Regular strength enteric coated aspirin tablets.jpg (Ragesoss, CC BY-SA 4.0); Senior-3336451 1920.jpg (pasja1000 (Pixabay), CC0); RBCs, Platelets,WBC in PBS.jpg (Ajay Kumar Chaurasiya, CC BY-SA 4.0); DNA Double Helix by NHGRI.jpg (NHGRI, Public domain). On-screen graphics: own.

AI voice note: the narration in the Short is an AI clone of my own voice (Chatterbox TTS by Resemble AI, MIT licence), used with my consent. I wrote the script and checked the figures against the sources above.

This page is general information, not medical or dental advice. Please talk to a doctor, dentist or pharmacist about your own health.