A new genetic analysis suggests low-dose aspirin may dramatically cut dementia risk in older adults who carry a specific genetic profile — a finding that could help explain why past trials found no overall benefit from the cheap, widely available drug, even as it raises a serious safety trade-off.
Researchers from Monash University examined genetic data from more than 13,500 participants in the ASPREE Trial (Aspirin in Reducing Events in the Elderly), focusing on genes associated with platelet count. Among participants in the top 20% for a platelet-count genetic score, just 1% of those taking aspirin developed dementia, compared with 3.3% of those given a placebo — a roughly 70% lower relative risk. The findings were published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.
A benefit with a real cost
The apparent protection came with a tradeoff: in that same genetic subgroup, 4.4% of aspirin users experienced major bleeding, compared with 2.1% of those on placebo. "Previous trials found aspirin didn't prevent dementia when everyone was considered together," said Dr. Peter Fransquet, the study's lead author and a research fellow at Monash's School of Public Health and Preventive Medicine. "In people with this particular genetic profile, we saw substantially fewer cases of dementia among those taking aspirin. It raises the possibility that genetics could one day help us identify who may benefit from a preventive treatment, rather than taking a one-size-fits-all approach."
An unexpected biological trail
Notably, the genetic signal researchers found was not linked to the well-established genetic risk factors for Alzheimer's disease, pointing instead toward platelet biology — the processes by which blood cells involved in clotting become active and stick together — as a previously underexplored avenue for dementia research. Dementia Australia estimates roughly 446,500 people in the country are living with the condition this year, a number projected to exceed one million by 2065, underscoring the urgency behind any new lead, however preliminary.
Not a reason to start taking aspirin yet
Fransquet was emphatic that the results need confirmation before they can guide real-world decisions. "We now need to confirm the finding in other studies and ultimately test it in a trial designed specifically for people with this genetic profile," he said. "People shouldn't start taking aspirin to prevent dementia on the basis of this study without consulting with their doctor, particularly given the increased risk of serious bleeding." If the link holds up in further research, he added, aspirin's low cost and wide availability could make genetically targeted dementia prevention a realistic option — but that remains a research question, not a clinical recommendation, for now.