Risks and Benefits of Daily Aspirin
Does an aspirin a day keep heart disease and cancer away? Research suggests it could help, and the U.S. Preventive Services Task Force (USPSTF)—a federal panel of medical experts who evaluate scientific evidence and make recommendations about preventive healthcare—agrees, up to a point.
In April of this year, the task force updated its 2007 and 2009 guidelines and now recommends that some people ages 50 to 69 with a 10 percent or higher risk of cardiovascular disease take a low-dose daily aspirin for the primary prevention of heart attack, stroke, and colorectal cancer (cancer of the colon or rectum). The revised guidance reflects the latest high-quality evi- dence based on long-term aspirin use.
The USPSTF already recommends a daily low-dose aspirin (75 to 100 milli- grams) for certain people who have had a first heart attack or stroke, or who have certain forms of cardiovascular disease, to reduce the risk of a second heart attack or stroke or of dying from cardiovascular disease.
But don’t go reaching for that baby aspirin just yet. The recommendation comes with certain caveats that warrant an in-depth discussion with your doctor to weigh aspirin’s benefits and risks, such as gastrointestinal bleeding, which increases with age.
Weighing the pros and cons
Although aspirin is a common over-the-counter medication with a variety of uses, it is still a drug associated with a number of risks. Aspirin thins the blood, helping to prevent blood clots that could cause a heart attack or an ischemic stroke (the type of stroke caused by a blood clot). But it also heightens the risks of bleeding and ulceration of the stomach wall, especially when taken for a long duration, and can increase the risk of hemorrhagic stroke (stroke caused by bleeding in the brain). This risk alone can rule out aspirin therapy for many people.
The new USPSTF recommendation, published online in April 2016 by the Annals of Internal Medicine, addressed aspirin’s use in healthy individuals who have no known cardiovascular disease but desire protection against developing heart disease and colorectal cancer in the future.
According to the USPSTF, you may be a candidate for daily aspirin therapy for the primary prevention of cardiovascular disease and colorectal cancer if:
• You are in your 50s, have a 10 percent or greater risk of having a heart attack or stroke over the next 10 years, have a life expectancy of at least 10 years, and do not have an increased risk of gastrointestinal bleeding. Calculate your heart attack risk here.
• You are in your 60s, have a high risk of having a heart attack or stroke over the next 10 years, have a life expectancy of at least 10 years, and do not have an increased risk for gastrointestinal bleeding.
• You meet one of the above requirements and are willing to take a daily aspirin for at least 10 years—the length of time it may take for the benefits to take effect.
For people 70 and older (or younger than 50), the advice isn’t so clear cut. The USPSTF wasn’t able to make any recommendations for or against aspirin use for primary prevention of heart disease or colorectal cancer for these age groups because of insufficient evidence to indicate that the benefits of therapy are worth the potential risks. However, the USPSTF notes that aspirin should not be ruled out for older adults because many have significant heart attack and stroke risks and aspirin therapy’s potential benefits could be substantial.
What’s your risk?
People in their 50s benefit the most from aspirin therapy for heart disease prevention, says the USPSTF, whereas the benefit for people in their 60s is not as high when weighed against an increased bleeding risk. If you’re considering aspirin therapy, you and your doctor should have a serious conversation about what’s best for you. You may feel that your personal net benefit may not justify the bleeding risks or even the inconvenience of taking an aspirin each day. Or you may place a higher value on aspirin’s potential benefits than on your concern for its potential risks.
Risk factors for CVD include older age, male sex, high cholesterol, high blood pressure, diabetes, and smoking. Certain races and ethnicities are at increased risk, including African-Americans, Mexican-Americans, Asian-Americans, American Indians, and native Hawaiians.
A cancer prevention bonus
The reasons for aspirin’s protective effect against colorectal cancer are not fully understood. Researchers suspect that aspirin blocks the body’s inflammatory response, which, when chronic, can lead to changes and mutations that promote tumors.
The USPSTF does not outright recommend taking an aspirin solely for the purpose of preventing colorectal cancer, but the task force says that the drug can provide a combined benefit for people ages 50 to 69 at average risk for colorectal cancer who are on an aspirin regimen for cardiovascular disease prevention.
However, it takes five to 10 years of daily aspirin use to reduce the incidence of colorectal cancer. This benefit isn’t apparent until 10 years after aspirin therapy is started. Therefore, people ages 50 to 59 stand to gain the biggest net benefit.