Low-Dose Aspirin and Dementia Prevention: A New Twist
For years, scientists have explored whether aspirin could help prevent dementia. Aspirin is an anti-inflammatory, and inflammation is thought to be a major driver of Alzheimer's disease. But the large 2018 ASPREE trial poured cold water on the idea: in healthy older adults, taking 100 mg of low-dose aspirin daily did not significantly reduce dementia risk. A 2020 follow-up analysis using ASPREE data seemed to confirm that finding.
Now, researchers have taken a different angle—re-examining the ASPREE data through a genetic lens—and found a striking difference.
What Did the New Study Find?
The new study, published in Alzheimer's & Dementia, analyzed polygenic scores (DNA-based estimates of genetic predisposition to disease) and genetic makeup of about 5,000 ASPREE participants. The key finding: people whose scores predicted higher platelet counts—making blood stickier and more clot-prone—benefited from low-dose aspirin for dementia prevention.
- Among people in the top 20% for a platelet-count genetic score, about 1% developed dementia on aspirin, compared with 3.3% on placebo.
- In relative terms, their dementia risk dropped by roughly 70%.
- But the same group also had about twice the rate of major bleeding on aspirin.
- For the other 80% of participants, aspirin showed no dementia benefit.
In short, the benefit and the risk were concentrated in the same small group—and that trade-off is the whole story.
What Do the Findings Mean for the General Public?
First, don't rush to interpret your last blood count. The study used polygenic scores, which reflect genetic tendency, not a measured platelet value from a routine blood test. Someone with a high genetic score may have a perfectly normal platelet count on labs. Conversely, a high platelet count on routine bloodwork usually reflects something temporary, such as iron deficiency, inflammation, infection, or recovery from surgery.
Second, polygenic score testing is not yet commonplace, and these findings come from a small subgroup pulled from existing research. More studies are needed to replicate them—realistically years away. Experts discourage people from running consumer DNA files through online calculators to self-diagnose.
More importantly, the bleeding risks of regular aspirin use are well studied. Current U.S. Preventive Services Task Force guidance recommends against starting low-dose aspirin for primary prevention in adults 60 and older because bleeding risk offsets the benefit. This study doesn't change that. If you are already prescribed daily aspirin after a cardiac event, do not stop taking it without talking to your doctor.
Risks of aspirin-associated bleeding rise with age, a history of ulcers or gastrointestinal bleeding, kidney disease, uncontrolled blood pressure, heavy alcohol use, and the use of other medications including blood thinners, NSAIDs like ibuprofen or naproxen, SSRIs, or steroids.
How Aspirin and Dementia Could Be Linked
The findings suggest dementia was potentially prevented—not treated—in the high-platelet genetic group. Platelets help form clots and also release chemical signals that drive inflammation. Aspirin blocks platelet activation and lowers inflammation. Small vessel disease in the brain, caused by tiny clots and damaged vessel walls, contributes to a large share of dementia cases. In people with a genetic tendency toward more platelet activity, aspirin might reduce this small vessel damage and the chronic inflammation behind it.
How to Lower Dementia Risk
Rather than fixating on aspirin, focus on proven prevention strategies. The 2024 Lancet Commission on dementia prevention highlights controlling high blood pressure, managing diabetes, quitting smoking, limiting alcohol, regular exercise, a healthy diet, and maintaining social and cognitive activity as ways to reduce dementia risk. Tracking blood pressure, blood sugar, and blood lipids is fundamental to chronic disease management and brain health.
The Xiaoshu Health App can sync with Apple Health to track relevant metrics, helping you continuously record blood pressure, heart rate, sleep, and activity data as a daily reference for dementia risk management.