A daily aspirin did not extend healthy old age, and raised the risk of serious bleeding

The most rigorous test of a daily low-dose aspirin as a longevity measure in healthy older adults found it did nothing to extend disability-free life, and raised the rate of major bleeding [s1]. In the ASPREE trial, aspirin also produced a small, unexpected increase in deaths, driven mainly by cancer — the opposite of what decades of hope had assumed [s2].

For a cheap, ubiquitous pill often taken on the theory that it can only help, that is a pointed result: in people who start out well, aspirin's ledger came out negative.

The trial

ASPREE enrolled 19,114 community-dwelling people in Australia and the United States who were 70 or older — or 65 or older among Black and Hispanic Americans — and free of cardiovascular disease, dementia and physical disability at the start [s1]. From 2010 through 2014 they were randomly assigned to 100 mg of enteric-coated aspirin a day or a matching placebo: 9,525 to aspirin and 9,589 to placebo, with a median age of 74 and 56.4 per cent women [s1]. The primary endpoint was deliberately chosen to capture healthy longevity rather than any single disease — a composite of death, dementia or persistent physical disability, that is, survival free of the things that end an independent life [s1].

The trial was stopped at a median of 4.7 years once it was clear aspirin would bring no benefit on that endpoint [s1]. The event rate for the death-dementia-disability composite was 21.5 per 1,000 person-years on aspirin against 21.2 on placebo, a hazard ratio of 1.01 (95% confidence interval 0.92 to 1.11) — as close to no effect as a large trial produces [s1].

The harms

Where aspirin did move the numbers, it moved them the wrong way. Major haemorrhage occurred in 3.8 per cent of the aspirin group versus 2.8 per cent of the placebo group, a hazard ratio of 1.38 (95% CI 1.18 to 1.62) [s1]. Counted as a rate, serious bleeding ran at 8.6 per 1,000 person-years on aspirin against 6.2 on placebo [s3]. This is the well-known cost of an antiplatelet drug, and in a healthy elderly population it was not offset by benefit elsewhere.

The mortality finding was the surprise. Death from any cause was 12.7 per 1,000 person-years on aspirin and 11.1 on placebo, a hazard ratio of 1.14 (95% CI 1.01 to 1.29), with 1,052 deaths in total [s2]. Cancer accounted for most of the excess — an extra 1.6 cancer deaths per 1,000 person-years, with cancer-related death in 3.1 per cent on aspirin versus 2.3 per cent on placebo (hazard ratio 1.31, 95% CI 1.10 to 1.56) [s2]. The investigators flagged this as unexpected, at odds with earlier work suggesting aspirin lowers cancer risk, and to be interpreted with caution rather than as settled fact [s2].

Nor did aspirin buy the cardiovascular protection that is its usual rationale. In this primary-prevention population the rate of cardiovascular events was 10.7 per 1,000 person-years on aspirin and 11.3 on placebo, a hazard ratio of 0.95 (95% CI 0.83 to 1.08) — no meaningful reduction [s3].

The limits, stated plainly

ASPREE tested a specific proposition: starting daily aspirin in healthy older adults with no established heart disease. It does not speak to people who have already had a heart attack or stroke, for whom aspirin remains an established secondary-prevention therapy — a different population and a different risk-benefit balance entirely [s3]. And 4.7 years is a medium-term window; a longer follow-up could shift the cancer signal, which is why the authors urged caution over that particular finding [s2]. What the trial does establish, robustly, is that in well older people aspirin is not a healthy-longevity intervention and carries a real bleeding cost [s1][s3].

What it means for a reader

The lesson ASPREE teaches is the one the whole longevity field keeps relearning: a plausible mechanism and a cheap pill are not evidence, and only a large randomised trial with a hard endpoint can tell benefit from harm. Aspirin cleared that bar and failed it [s1]. It joins the growing list of interventions that looked promising for extending healthy life and did not survive a proper test in the healthy elderly — including statins in older adults without heart disease, whose trial asked much the same question.

The finding also reframes what actually compresses late-life disability, the subject of our piece on the healthspan–lifespan gap: the strongest evidence still points to behaviours rather than pills, above all the dose-response link between physical activity and mortality. What to watch is longer-term ASPREE follow-up on the cancer question, but the core message is already firm: for a healthy older adult, a daily aspirin is not a longevity strategy.

This article is informational and is not medical advice. Anyone taking or considering aspirin, especially long term, should review it with a clinician who knows their history — and should not stop a prescribed aspirin on the strength of a news article.