A new analysis from Monash University, published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, suggests low-dose aspirin may be linked to a far lower dementia risk in older adults with a specific genetic profile.

Researchers used genetic data from more than 13,500 participants in the landmark ASPREE trial (Aspirin in Reducing Events in the Elderly) to test whether gene differences could explain aspirin's varying effects on dementia. The clearest signal came from genes associated with platelet count.

Among participants in the highest 20% of platelet count genetic scores, just 1% of aspirin users developed dementia versus 3.3% on placebo — roughly a 70% lower relative risk.

The result is striking because earlier trials found no overall protective effect of aspirin against dementia when all participants were considered together.

Lead author Dr. Peter Fransquet, a Research Fellow at Monash's School of Public Health and Preventive Medicine, said the findings suggest 'there may be more to the story' and raise the possibility that genetics could one day identify who may benefit from preventive treatment rather than a one-size-fits-all approach.

According to both ScienceDaily and ua.news, the genetic association did not involve the established genetic risk factors for Alzheimer's disease, instead pointing researchers toward platelet biology and platelet activation as a new avenue of investigation.

The potential benefit came with a serious trade-off. In the same high-genetic-score group, 4.4% of aspirin users experienced major bleeding, compared with 2.1% of those on placebo — roughly double the risk.

The researchers cautioned that people should not start taking aspirin to prevent dementia on the basis of this study without consulting a doctor, particularly given the bleeding danger.

The stakes are high: ScienceDaily reports Dementia Australia estimates approximately 446,500 people in Australia are living with dementia in 2026, a number expected to exceed one million by 2065.

If the finding holds, aspirin's low cost and wide availability could make personalized dementia prevention a real possibility.

The researchers stress the results must be confirmed before they can guide medical recommendations.

According to ScienceDaily, the next step is to investigate whether the association appears in other populations, followed by a clinical trial specifically involving people with the genetic profile identified in the analysis.

Dr. Fransquet noted that if the finding holds up, aspirin's cheapness and availability could make personalized dementia prevention a real possibility.

Until then, the study stands as a hypothesis-generating result: a clue that platelet biology may shape who benefits from aspirin, not a reason to change any medication routine without medical advice.