Will an Aspirin a day keep the cardiologist away?

The question

Several of my friends take Aspirin daily to guard against heart disease. I'm in my 50s and in fairly good health. But it would be nice to reduce my chances of a having a heart attack down the road. Is there any reason not to take Aspirin?

The answer

All drugs, no matter how safe or benign they might seem, pose some risks. So, you should weigh those risks against the potential benefits you hope to gain by taking a medication.

It's true that Aspirin – also known as acetylsalicylic acid (ASA) – has a role to play in treating cardiovascular disease because of its anti-clotting properties.

Most heart attacks and strokes happen when a patch of cholesterol-rich plaque attached to the inside wall of a blood vessel bursts open and releases debris. Tiny blood cells called platelets will collect at the scene of the rupture and clump together to form a clot. That clot, if it's big enough and in a critical spot in the heart or brain, can block the flow of blood – resulting in either a heart attack or ischemic stroke.

Aspirin reduces the ability of platelets to stick together and thereby inhibits the formation of clots. In terms of preventing heart attacks and strokes, that's a good thing. But Aspirin also increases the risk of bleeding.

Those who take Aspirin regularly are prone to nose bleeds, which is usually a minor annoyance. Some people, though, do suffer from more serious bleeding in the stomach and colon. In rare cases, Aspirin is associated with bleeding in the brain – known as a hemorrhagic stroke.

So, there are certainly pros and cons to taking Aspirin.

Numerous studies have determined that the benefits outweigh the risks in patients who have clearly established cardiovascular disease. That means they've already had at least one heart attack or stroke, or undergone an operation to open up narrowed blood vessels.

In this group, taking a low-dose 81-milligram "baby" Aspirin each day can reduce the likelihood of having a heart attack or stroke by 25 per cent, says Dr. Paul Oh, medical director of the cardiovascular disease prevention and rehabilitation program at the Toronto Rehabilitation Institute.

"The benefits of avoiding a future heart attack or stroke are very large, compared with the relatively small risk of bleeding," he adds. And a baby Aspirin is just as effective at reducing the risk as a 325-milligram regular-strength tablet, which carries a higher chance of bleeding.

But will a baby Aspirin a day keep the cardiologist away for people who are generally healthy? That question has stirred much debate in the medical community. To add some clarity to this issue, the U.S. Preventive Services Task Force has carried out several reviews of the available research. The most recent update was published in June, 2016.

The task force's findings are a mixed bag. It concluded that there is simply not enough evidence to say whether a baby Aspirin a day provides a net benefit to healthy adults under the age of 50 or those over the age of 69.

However, it found there is a "moderate" benefit for those between the ages of 50 and 59 who face a 10 per cent or greater probability of developing heart disease in a decade.

For adults between the ages of 60 to 69 with a 10-per-cent risk of heart disease in the next 10 years, there is a "small" benefit to taking Aspirin. (The risk of bleeding increases with age. As a result, the net benefit of Aspirin therapy tends to diminish in the 60-to-69 group.)

The conclusions of the task force raise another question. How do you figure out your chances of developing heart disease in the next decade? That figure is determined by several factors, including your blood pressure, cholesterol levels and whether or not you have diabetes or smoke.

On the internet, you can find heart-disease risk calculators that can be used to assess your situation – and if your risk is likely to hit the critical 10-per-cent mark.

It's worth mentioning that the task force also looked at the ability of Aspirin to help prevent colorectal cancer. There is a growing body of research that suggests this commonly used pain reliever might be a cancer fighter, too. But you have to take the drug daily for a decade to reap those potential benefits, the task force says.

Of course, it's not necessarily easy to evaluate all the risks and benefits associated with taking Aspirin.

For that reason, it's a good idea for people to consult with their health-care providers before they start popping a tablet regularly, says Dr. Fuad Moussa, a cardiac surgeon at Sunnybrook Health Sciences Centre in Toronto.

As Moussa puts it: "With any medication, there are potential adverse side effects. And if you don't need it, why take it?"

Paul Taylor is a Patient Navigation Advisor at Sunnybrook Health Sciences Centre. He is a former health editor of The Globe and Mail. You can find him on Twitter @epaultaylor and online at Sunnybrook's Your Health Matters.