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Aspirin reduces risk of death, heart disease or cancer, with some increase in the risk of stroke or major bleeding

Sutcliffe P, Connock M, Gurung T, et al. Aspirin for prophylactic use in the primary prevention of cardiovascular disease and cancer: a systematic review and overview of reviews. Health Technol Assess. 2013;17:1-253.

Review questions

Does aspirin prevent heart disease or cancer? Does it cause harm?


Aspirin may prevent heart disease or cancer in people who have not had these diseases, but it can also cause harm (e.g., bleeding and stroke).

How the review was done

The researchers did a systematic review, searching for studies that were published up to September 2012.

They found 22 systematic reviews and 5 randomized controlled trials. Analyses included about 25,000 to 100,000 people.

People in the studies were older than 18 years of age and did not have heart disease or cancer.

Aspirin was compared with placebo, usual care, or no aspirin.

What the researchers found

Aspirin for preventing disease or death

Most studies tested a daily low dose of aspirin (75 to 100 mg per day).

Compared with control (placebo, usual care, or no aspirin), aspirin reduced death, heart disease, cancer, and deaths due to cancer by a small amount. For example, deaths were reduced by 33 to 85 per year for 100,000 people.

Harms of aspirin

Compared with control (placebo, usual care, or no aspirin), aspirin increased major bleeding or stroke, although the risks were small. The increase in risk of major bleeding was 35 to 49 per year for 100,000 people, whereas the increase in risk of bleeding into the brain (hemorrhagic stroke) was 8 to 10 per year for 100,000 people.


In people who don’t have heart disease or cancer, aspirin may reduce risk of death and these diseases by a small amount. People taking aspirin are a little more likely to have a stroke or major bleeding than those not taking aspirin.

Aspirin vs placebo, usual care, or no aspirin for preventing heart disease or cancer


Effect of aspirin


33 to 85 fewer people out of 100,000 will die each year

Heart disease

55 to 84 fewer people out of 100,000 will get heart disease each year

Death due to heart disease


Not reported

Death due to cancer

25 to 66 fewer people out of 100,000 will die of cancer each year.

Major bleeding

35 to 49 people out of 100,000 taking aspirin will have major bleeding each year


8 to 10 people out of 100,000 taking aspirin will have a stroke each year


Related Topics


A harmless, inactive, and simulated treatment.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

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