Patient information: The metabolic syndrome

METABOLIC SYNDROME OVERVIEW

The metabolic syndrome, also called insulin resistance syndrome or syndrome X, is not a disease but a group of characteristics that, in combination, increase your risk of developing type 2 diabetes and heart disease. These characteristics include obesity, high blood pressure, elevated blood sugar levels, and high triglycerides (fat-like substances in the blood). Keeping your weight, blood sugar, and cholesterol and triglyceride levels under control can help you to live longer and decrease your risk of heart attack and stroke.

There is controversy as to whether the characteristics of the metabolic syndrome warrant classification as a "syndrome". Being diagnosed with the metabolic syndrome does not appear to put you at any greater risk of type 2 diabetes or heart disease beyond the risk of the individual characteristics. In addition, treatment of the metabolic syndrome is not different than the treatment of each individual characteristic.

More detailed information about metabolic information is available by subscription. (See "The metabolic syndrome (insulin resistance syndrome or syndrome X)".)

WHAT IS METABOLIC SYNDROME?

The metabolic syndrome is a group of characteristics. You do not need to have all of the characteristics to have it. However, a person with one characteristic is more likely to have others. Most expert groups define metabolic syndrome as the presence of three or more of the following characteristics in a person:

• Obesity, especially in the abdominal area (defined by some groups as a waist size greater than 94 to 102 cm (38 to 41 in) in men or greater than 80 cm (32 in) in women)
• Impaired fasting glucose (fasting blood sugar of 100 to 125 mg/dL (5.6 to 7 mmol/L)
• Increased blood pressure (130/85 or higher) or if you take medication for high blood pressure
• Increased fasting levels of triglycerides (greater than 150 to 180 mg/dL or 1.7 mmol/L) and/or decreased fasting HDL cholesterol (less than 40 mg/dL or 1 mmol/L for men or 50 mg/dL or 1.3 mmol/L for women), or if you take medication for high triglycerides or low HDL cholesterol

HOW COMMON IS METABOLIC SYNDROME?

Metabolic syndrome is becoming increasingly common. In one study performed between 1999 and 2002, more than 34 percent of participants were classified as having metabolic syndrome [1]. This number is significantly increased from a similar study performed between 1988 and 1994, in which 22 percent of people had metabolic syndrome.

The following factors are thought to increase the risk of developing metabolic syndrome:

• Being overweight (body mass index of 25 kg/m2 or more, (calculator 1)
• Menopause (in women)
• Increasing age
• Smoking
• Eating a high carbohydrate diet
• Lack of physical activity
• Family history of diabetes or metabolic syndrome

Health risks associated with metabolic syndrome

Diabetes — Type 2 diabetes is much more likely to develop among people with the metabolic syndrome [2]. Healthy lifestyle changes, such as weight loss and exercise, can help to reduce the risk of developing type 2 diabetes. (See "Patient information: Diabetes mellitus type 2: Overview".)

Cardiovascular disease — People with metabolic syndrome are at increased risk for developing cardiovascular disease. Cardiovascular disease includes coronary artery disease (collections of fatty plaques inside the heart's blood vessels), cerebrovascular disease (collections of fatty plaques inside the blood vessels leading to the brain), and high blood pressure. Cardiovascular disease can lead to heart attack, stroke, or angina (chest pain).

METABOLIC SYNDROME DIAGNOSIS

The metabolic syndrome is diagnosed based upon a physical examination and measurement of fasting (before breakfast) blood sugar, cholesterol, and triglyceride levels. A description of how blood glucose and cholesterols levels are measured is available separately. (See "Patient information: Diabetes mellitus type 2: Overview" and "Patient information: High cholesterol and lipids (hyperlipidemia)".)

METABOLIC SYNDROME TREATMENT

The goals of treatment for the metabolic syndrome are to:

• Reduce or eliminate underlying problems (eg, obesity, lack of activity) by losing weight and becoming more active
• Treat cardiovascular risk factors, such as high blood pressure and cholesterol, if these problems persist despite losing weight and exercising.

Weight loss — Management of the metabolic syndrome usually includes weight loss and increased physical activity. The diet should be low in fat and cholesterol.

Several dietary approaches may reduce the risks associated with metabolic syndrome:

• The Mediterranean diet is high in fruits, vegetables, nuts, whole grains, and olive oil. This diet can help to lower weight, blood pressure, lipids, and improve insulin resistance.
• The DASH (Dietary Approaches to Stop Hypertension) diet can reduce blood pressure, weight, lipids and fasting blood glucose levels. The DASH diet requires the person to eat no more than 2400 mg of sodium per day, four to five servings of fruit, four to five servings of vegetables, two to three servings of low-fat dairy products, and all foods must contain less than 25 percent total fat per serving. (See "Patient information: Low sodium diet".)

Exercise — Exercise can assist in weight loss and can also help to reduce the size of the abdomen, especially in women. Current guidelines recommend at least 30 minutes of moderate physical activity, such as brisk walking, most days of the week. (See "Patient information: Exercise".)

Removing abdominal fat with liposuction does not improve insulin sensitivity or reduce the risk of cardiovascular disease.

Reduce the risk of type 2 diabetes — Losing weight (if you are overweight or obese) and staying active can reduce the risk of developing type 2 diabetes.

Reduce cholesterol — High levels of LDL (bad) cholesterol increase the risk of coronary artery disease. In people with metabolic syndrome, an LDL level of less than 80 to 100 mg/dL is recommended.

If diet and weight loss do not adequately reduce your LDL levels, a medication may be recommended. Treatment of high LDL levels is discussed separately. (See "Patient information: High cholesterol and lipids (hyperlipidemia)".)

Reduce blood pressure — Maintaining a healthy blood pressure is an important goal, especially in people with the metabolic syndrome.

• High blood pressure is a BP greater than 140/80 mmHg
• Prehypertension is a BP greater than 120 to 139/80 to 89 mmHg.

There is no guideline as to when people with metabolic syndrome should be treated for high blood pressure, although many experts recommend treatment if your blood pressure is greater than 130/80 mmHg.

If diet and weight loss do not adequately reduce your blood pressure, one or more blood pressure medications may be recommended. Treatment of high blood pressure is discussed separately. (See "Patient information: High blood pressure treatment in adults".)

Quit smoking — Smoking cigarettes significantly increases the risk of coronary artery disease, and has many other health risks as well. You and your family are strongly advised to stop cigarette smoking. (See "Patient information: Smoking cessation".)

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Diabetes mellitus type 2: Overview
Patient information: High cholesterol and lipids (hyperlipidemia)
Patient information: Low sodium diet
Patient information: Exercise
Patient information: High blood pressure treatment in adults
Patient information: Smoking cessation

Professional Level Information:
Insulin resistance: Definition and clinical spectrum
The metabolic syndrome (insulin resistance syndrome or syndrome X)

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/metabolicsyndrome.html)

• American Diabetes Association

      (www.diabetes.org/food-nutrition-lifestyle/lifestyle-prevention/weight-loss/healthy-weight-loss.jsp)

• American Heart Association

      (www.americanheart.org/presenter.jhtml?identifier=4756)

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