What Is Metabolic Syndrome?

Metabolic syndrome is the name for a group of risk factors linked to overweight and obesity. These risk factors increase your chance of having heart disease and other health problems, such as diabetes and stroke.

The term "metabolic" refers to the biochemical processes involved in the body's normal functioning. Risk factors are traits, conditions, or habits that increase your chance of getting a disease.

In this article, "heart disease" refers to coronary heart disease (CHD). CHD is a condition in which a fatty substance called plaque (plak) builds up inside the coronary (heart) arteries. Plaque narrows the arteries and reduces blood flow to your heart muscle. This can lead to chest pain, a heart attack, heart damage, or even death.

Metabolic Risk Factors

The five conditions described below are metabolic risk factors. You can develop any one of these risk factors by itself, but they tend to occur together. Metabolic syndrome is diagnosed if you have at least three of these metabolic risk factors.

• A large waistline. This also is called abdominal obesity or "having an apple shape." Excess fat in the abdominal area is a greater risk factor for heart disease than excess fat in other parts of the body, such as on the hips.
• A higher than normal triglyceride level (or you're on medicine to treat high triglycerides). Triglycerides are a type of fat found in the blood.
• A lower than normal HDL cholesterol level (or you're on medicine to treat low HDL cholesterol). HDL is sometimes called "good" cholesterol because it helps remove cholesterol from your arteries. A low HDL cholesterol level raises your risk of heart disease.
• Higher than normal blood pressure (or you're on medicine to treat high blood pressure). Blood pressure is the force of blood pushing against the walls of your arteries as your heart pumps out blood. If this pressure rises and stays high over time, it can damage your heart and lead to plaque buildup.
• Higher than normal fasting blood sugar (or you're on medicine to treat high blood sugar). Mildly high blood sugar may be an early sign of diabetes.

Overview

Your risk of heart disease, diabetes, and stroke increases with the number of metabolic risk factors you have. In general, a person who has metabolic syndrome is twice as likely to develop heart disease and five times as likely to develop diabetes as someone who doesn't have metabolic syndrome.

Other risk factors, besides those described above, also increase your risk of heart disease. For example, a high LDL cholesterol level and smoking are major risk factors for heart disease, but they aren't part of metabolic syndrome.

Even having a single risk factor raises your risk of heart disease. You should try to control every risk factor you can to reduce your risk.

The chance of developing metabolic syndrome is closely linked to overweight and obesity and a lack of physical activity. Insulin resistance also may increase your risk of metabolic syndrome.

Insulin resistance is a condition in which the body can't use its insulin properly. Insulin is a hormone the body uses to help change glucose (sugar) into energy. Insulin resistance can lead to high blood sugar levels, and it's closely linked to overweight and obesity.

Genetics (ethnicity and family history) and older age are other important underlying causes of metabolic syndrome.

Outlook

About 47 million adults in the United States (almost 25 percent) have metabolic syndrome, and the number continues to grow.

The increasing number of people who have this condition is linked to the rise in obesity rates among adults. In the future, metabolic syndrome may overtake smoking as the leading risk factor for heart disease.

It's possible to prevent or delay metabolic syndrome, mainly with lifestyle changes. A healthy lifestyle is a lifelong commitment. Successfully controlling metabolic syndrome takes a long-term effort and teamwork with your health care providers.

Revised January 2010