You’ve probably heard that taking a daily dose of aspirin can lower your risk of heart attack (1-7). With about 20% of older adults taking aspirin as a preventative strategy (8;9), there is no question that it is commonly prescribed. But do its benefits outweigh its risks? This has been a matter of controversy (8), especially when it comes to healthy adults.
Why prescribe aspirin to prevent heart attacks? Aspirin (or acetylsalicylic acid) prevents blood clots (1). Blood clotting occurs when cells called platelets clump together and seal up a bleeding wound. Because blood clots that block the flow of blood to the heart can lead to a heart attack, stopping this process lowers your risk of a heart attack.
What’s the catch? Because taking aspirin can make it difficult to form blood clots, it also increases the risk of internal bleeding (1;2;8;10).
So, is aspirin a safe choice for heart attack prevention when both the benefits and risks are considered together? This is a matter of hot debate. Some guidelines recommend it for people at a higher risk for heart attack (8;11;12), whereas other guidelines don’t recommend it at all (8;13). And while there is research that supports its use in people with a history of heart attack or stroke, (8;11;12), evidence supporting its use in healthy adults is less clear (8;14;15).
Given all of the conflicting evidence and guidelines, a recent systematic review took a closer look at the benefits and risks of aspirin use in adults with no history of heart disease—including outcomes such as stroke, heart attacks, blood clots in the legs, and so on (8).
So, just what did this review find?
What the research tells us
The results showed that taking aspirin didn’t lower the risk of death from any cause in adults without a history of heart disease, compared to those taking placebo or nothing at all. These findings held true even when considering people’s risk of major cardiovascular events, if they had diabetes or not, and the dose of aspirin they were taking (in most cases, people were taking 75 mg to 100 mg per day). What’s more, aspirin didn’t reduce the risk of death from heart disease-related complications or the risk of stroke.
With respect to having a heart attack, the results varied across studies; but even in the best case scenario heart attacks were slightly less common in adults taking aspirin—about 3 fewer people out of 1000 having a heart attack. That being said, when older studies were removed from the analysis and only newer studies considered, no reduction in heart attacks among those taking aspirin was seen. In terms of negative side effects, those taking aspirin were more likely to experience major bleeding—including bleeding inside the brain or skull.
So, in people with no history of heart disease, aspirin may do more harm than good. But, before tossing your bottle of aspirin from your medicine cabinet, make sure to talk to your health care provider about its potential risks and benefits for you as an individual (8).
Folks should also keep in mind that the findings discussed here are for adults who do not have a history of heart disease, and so do not apply to those with a history of heart disease or stroke.