Daily aspirin did not slow aging-related decline; women slipped slightly

Daily low-dose aspirin, one of the most widely taken drugs in the world, did not help older adults hold on to the everyday abilities that define healthy aging, according to a new analysis of a large trial. In women, those abilities slipped slightly faster on aspirin than on a dummy pill.¹ The work, published in the journal GeroScience, re-examined data from the ASPREE trial, which followed more than 18,000 people for nearly five years.¹

What happened

ASPREE (short for ASPirin in Reducing Events in the Elderly) enrolled 19,114 people living in the community who were relatively healthy, without major physical disability, dementia or known heart disease. Each was randomly assigned to take either 100 milligrams of aspirin or a placebo (a dummy pill) every day.¹ Coverage of the new paper gives their ages as 65 to 98;¹ the trial team’s own summary describes them as aged predominantly 70 and older, living in Australia and the United States.²

The trial’s main result, reported years ago, was that aspirin did not lengthen survival free of dementia and physical disability.¹ But death, dementia and disability come late. So the researchers asked whether a more sensitive measure of day-to-day function might pick up effects that the original goal missed.¹

A score for how well people function

The team used an idea called intrinsic capacity, introduced by the World Health Organization in its 2015 report on healthy aging. Instead of counting diseases, it combines a person’s physical and mental abilities in areas older people value: getting around, thinking, vitality and psychological well-being.¹

ASPREE had not planned to measure this, so the researchers built a four-part score from data the trial had already collected:¹

• Thinking: a set of tests covering overall thinking, memory, language, planning and processing speed.¹
• Getting around: walking speed over a timed three-meter walk.¹
• Vitality: handgrip strength, measured with a grip meter.¹
• Well-being: a short depression questionnaire, scored so that higher always meant better.¹

The score was calculated every year for 18,581 people, 97.2% of the trial: 10,451 women and 8,130 men.¹ Walking speed and grip were not measured in years one and three, so the researchers filled in those years by estimation. A check using only the real measurements gave the same results, the coverage reports.¹

Before testing aspirin, the team checked that the score meant something. It was lower in older participants and tracked closely with a 67-item index of accumulated health problems.¹ It also predicted the future: over a median of 4.7 years, women in the lowest fifth of scores at the start were about 4.6 times as likely as those in the top fifth to die or develop dementia or lasting disability, and men about 4.3 times as likely.¹

What aspirin did to the score

Analyzing men and women separately, the researchers found that women on aspirin showed a small but statistically significant faster decline in the score than women on the dummy pill: about 0.006 units more per year.¹ In plain terms, the difference is real by the study’s statistics but slight. The overall conclusion reported is that aspirin does not preserve functional capacity in older adults.¹ The coverage available to Biohack describes the result in women in detail; it does not give the separate figures for men.

What it does not show

• It was not the trial’s question. The score was assembled after the fact from existing data, which makes this a secondary analysis. Findings like this can point to patterns but are weaker than a result the trial was designed to test.¹
• Part of the data was estimated. Two years of walking and grip measurements were filled in, though a check without them did not change the results.¹
• Overlap in the checks. The authors note that the score’s strong link with the health-problems index is partly because both include the same items, such as walking speed and grip.¹
• Mixed signals from aging clocks. In 560 Australian participants who gave blood, lower scores went with faster aging on several blood-based “aging clocks”, especially in women. A newer clock built specifically for this score showed no link.¹
• Why women and not overall is not explained in the material reviewed here, and the size of the change is small.

How it fits with earlier aspirin findings

The new result lines up with a run of neutral or unfavorable findings for aspirin in healthy older people. In the original trial there was an excess of deaths among those taking aspirin, almost entirely from cancer.³ One clinic’s review of the evidence notes that this cancer finding was unexpected, has not been seen in other aspirin trials, and faded with longer follow-up.⁴

That longer follow-up, called ASPREE-XT, tracked 15,633 participants for a median of about four more years after the trial ended. It found no effect of having been assigned aspirin on death, dementia or lasting disability, and no long-term effect on deaths, over almost a decade in total. Across the trial and follow-up combined, aspirin was linked to more major bleeding, with a hazard ratio of 1.24 (about 24% higher risk).² The authors concluded that low-dose aspirin “does not appear to be effective in promoting a healthy lifespan” in initially healthy older people.²

Guidelines had already moved. The US Preventive Services Task Force in 2022 recommended against starting aspirin to prevent a first heart attack or stroke in adults 60 and older, and the American College of Cardiology and American Heart Association say it should not be used routinely in anyone over 70.⁴ Those guidelines concern starting aspirin; they do not tell people already taking it to stop, a decision the same review says belongs with a doctor.⁴

Not every voice agrees on every group. A Harvard-affiliated physician argued in a January 2026 article that low-dose aspirin might still be considered for vulnerable older people during viral epidemics, while acknowledging that ASPREE-XT found no overall reduction in major heart events and more harm such as stomach bleeding.⁵

Back in 2015, before results were in, an ASPREE cancer researcher, Peter Gibbs, framed the question the trial was built to answer:

Older people may have the most to gain from aspirin, but their age also puts them at greater risk of adverse effects; nobody yet knows the aspirin balance for healthy older people.⁶

Who is behind it

ASPREE is run by researchers in Australia and the United States, with Monash University among the institutions involved. The extended follow-up was funded by the US National Institute on Aging and National Cancer Institute, and Australia’s National Health and Medical Research Council funded earlier phases of the project.² The coverage reviewed for this article does not list the funding or any conflicts of interest for the new GeroScience analysis itself.

What to watch next

ASPREE-XT was designed to keep monitoring this once-healthy group well into advanced age, with data collected through 2024, covering dementia, thinking, disability, depression, cancer and bleeding.³ The trial team has announced a further phase, called ASPREE-LT, with new funding.⁶ Further analyses could show whether the slight decline in women holds up in other measures or over longer follow-up, and whether the intrinsic capacity score proves useful as an early yardstick in other aging trials.