Your doctor can help you understand your risk of heart attack and stroke. Your doctor will use a few things to figure out your risk. These include:

• Your cholesterol numbers.
• Your blood pressure.
• Whether you have diabetes.
• Your age, gender, and race.
• Whether you smoke.

Your doctor might talk about your risk of having a heart attack or a stroke in the next 10 years. There are different online tools that doctors can use to calculate this risk. These tools are not perfect. They may show that your risk is higher or lower than it really is. But the tools can give you and your doctor a good idea about your risk.

Your doctor is likely to recommend a statin if you are at high risk of heart attack or stroke. For example, you may be at high risk if you have diabetes and you smoke.

If you are not at high risk of heart attack or stroke, it may not be as clear that you will benefit from taking a statin. You and your doctor may think about certain things, like your family history of coronary artery disease, to decide if medicine may be right for you.

In general:

• People at high risk will get more benefit from taking a statin than those at low risk.
• People at low risk will get less benefit from taking a statin. They may decide that a heart-healthy lifestyle is all they need to keep their risk low.

Everyone can help lower their risk of a heart attack or stroke with a heart-healthy lifestyle. This includes:

• Eating vegetables, fruits, nuts, beans, lean meat, fish, and whole grains. Limit things that are not so good for your heart, like sodium, alcohol, and sugar.
• Being active on most days of the week. To lower risk, try to do moderate exercise at least 2½ hours a week. Or try to do vigorous activity at least 1¼ hours a week.
• Losing weight if you need to, and staying at a healthy weight.
• Not smoking.
• Managing other health problems. These include diabetes and high blood pressure.

A heart-healthy lifestyle is important whether you take statins or not. Medicines don't take the place of healthy habits.

Statins lower the amount of bad (LDL) cholesterol in your blood.

Cholesterol is a type of fat in your blood. Your body needs it for many things, such as making new cells. But if you have too much cholesterol, it starts to build up in blood vessels called arteries. This problem is called atherosclerosis. It is the starting point for most heart and blood flow problems, including heart attacks and strokes.

Statins lower bad cholesterol by reducing how much of it your body makes. Statins also decrease inflammation around the cholesterol buildup (called a plaque). This may lower the risk that the plaque will break apart and cause a blood clot that can lead to a heart attack or stroke.

Some people who take statins report that they have more muscle aches. But it's not clear whether these are actually a side effect of statins.^{footnote 1}

A less common issue is diabetes. Statins may slightly raise the risk of diabetes in some people. This risk seems to be sightly higher in people who already have risk factors for getting diabetes.

The decision to take a statin is up to you. You can try it, and if you don't like the way it makes you feel, you can talk with your doctor. You may choose to take a different statin or a different dose to try to avoid side effects.

Benefits

Number of people who will have a heart attack or stroke in the next 10 years by risk level*

Risk of heart attack or stroke	With statins	Without statins
Low risk	2 out of 100	3 out of 100
Moderate risk	8 out of 100	10 out of 100
High risk	15 out of 100	20 out of 100

* These numbers are estimates based on research studies. The quality of the evidence is high.^{footnote 2footnote 3}

Evidence shows that statins may lower the chance of having a heart attack or stroke, especially for people who are at high risk.

Take a group of 100 people with a low risk of heart attack or stroke. Here are their chances of having one in the next 10 years:^{footnote 2footnote 3}

• If they don't take statins, about 3 out of 100 will have a heart attack or stroke. This means that about 97 out of 100 won't.
• If they do take statins, about 2 out of 100 will have a heart attack or stroke. This means that about 98 out of 100 won't.

Take a group 100 people with a moderate risk of heart attack or stroke. Here are their chances of having a heart attack or stroke in the next 10 years:

• If they don't take statins, about 10 out of 100 will have a heart attack or stroke. This means that about 90 out of 100 won't.
• If they do take statins, about 8 out of 100 will have a heart attack or stroke. This means that about 92 out of 100 won't.

Take a group of 100 people with a high risk of heart attack or stroke. Here are their chances of having a heart attack or stroke in the next 10 years:

• If they don't take statins, about 20 out of 100 will have a heart attack or stroke. This means that about 80 out of 100 won't.
• If they do take statins, about 15 out of 100 will have a heart attack or stroke. This means that about 85 out of 100 won't.

Risks

Risk of muscle aches

More research is being done to better understand the chances of having muscle problems from taking statins. Some people who take statins report that they have more muscle aches. But it's not clear how often these are actually a side effect of statins.^{footnote 1}

Risk of diabetes

Number of people who will get diabetes in the next 4 years

Risk	With statins	Without statins
Getting diabetes	5 out of 100	4 to 5 out of 100

* These numbers are estimates based on research studies.^{footnote 4}

Evidence shows that statins may raise the risk of diabetes in some people. The quality of this evidence is moderate. This risk seems to be slightly higher in people who already have risk factors for getting diabetes.

Take a group of 100 people . Here are their chances of getting diabetes in the next 4 years:^{footnote 4}

• With statins, about 5 out of 100 people will get diabetes. This means that about 95 out of 100 won't.
• Without statins, about 4 to 5 out of 100 people will get diabetes. This means that about 95 to 96 out of 100 won't.

Understanding the evidence

Some evidence is better than other evidence. Evidence comes from studies that look at how well treatments and tests work and how safe they are. For many reasons, some studies are more reliable than others. The better the evidence is—the higher its quality—the more we can trust it.

The information shown here is based on the best available evidence.^{footnote 2footnote 5footnote 4footnote 3}

The evidence is rated using four quality levels: high, moderate, borderline, and inconclusive.

Another thing to understand is that the evidence can't predict what's going to happen in your case. When evidence tells us that 2 out of 100 people who have a certain test or treatment may have a certain result and that 98 out of 100 may not, there's no way to know if you will be one of the 2 or one of the 98.