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Metabolic syndrome

Definition

Metabolic syndrome is a name for a group of risk factors that occur together and increase the risk for coronary artery disease, stroke, and type 2 diabetes.

Alternative Names

Insulin resistance syndrome; Syndrome X

Causes, incidence, and risk factors

Metabolic syndrome is becoming more and more common in the United States. Researchers are not sure whether the syndrome is due to one single cause, but all of the syndrome's risk factors are related to obesity.

Metabolic syndrome is associated with many conditions and risk factors. The two most important risk factors are:

• Extra weight around the middle of the body (central obesity). The body may be described as "apple-shaped."
• Insulin resistance, in which the body cannot use insulin effectively. Insulin is needed to help control the amount of sugar in the body.

Insulin helps blood sugar (glucose) enter cells. If you have insulin resistance, your body doesn't respond to insulin, and blood sugar cannot get into cells. As a result, the body produces more and more insulin. Insulin and blood sugar levels rise, affecting kidney function and raising the level of blood fats, such as triglycerides.

Other risk factors include:

• Aging
• Genes that make you more likely to develop this condition (genetic predisposition)
• Hormonal changes
• Lack of exercise

Symptoms

• Extra weight around your waist (central or abdominal obesity)

Signs and tests

According to the American Heart Association and the National Heart, Lung, and Blood Institute, metabolic syndrome is present if you have three or more of the following signs:

• Blood pressure equal to or higher than 130/85 mmHg
• Fasting blood sugar (glucose) equal to or higher than 100 mg/dL
• Large waist circumference (length around the waist):
  • Men - 40 inches or more
  • Women - 35 inches or more
• Low HDL cholesterol:
  • Men - under 40 mg/dL
  • Women - under 50 mg/dL
• Triglycerides equal to or higher than 150 mg/dL

Tests that may be done to diagnose metabolic syndrome include:

• Blood pressure measurement
• Glucose test
• HDL cholesterol level
• LDL cholesterol level
• Total cholesterol level
• Triglyceride level

Treatment

The goal of treatment is to reduce your risk of heart disease and diabetes. Your doctor will recommend lifestyle changes or medicines to help reduce your blood pressure, LDL cholesterol, and blood sugar.

Recommendations include:

• Lose weight. The initial goal is to lose between 7 and 10% of your current weight. This generally means that you need to eat 500 - 1,000 fewer calories per day.
• Get 30 minutes of moderate intensity exercise, such as walking, 5 - 7 days per week.
• Lower your cholesterol using weight loss, exercise, and cholesterol lowering medications, if needed.
• Lower your blood pressure using weight loss, exercise, and medications, if needed.

Some people may need daily low-dose aspirin.

People who smoke should quit.

Expectations (prognosis)

People with metabolic syndrome have an increased long-term risk for developing cardiovascular disease and type 2 diabetes.

Complications

• Atherosclerosis
• Diabetes
• Heart attack
• Kidney disease
• Nonalcoholic fatty liver disease
• Peripheral artery disease
• Stroke

Calling your health care provider

Call your health care provider if you have signs or symptoms of this condition.

Prevention

Preventing (and managing) the condition involves:

• Eating a diet low in fat, with a variety of fruits, vegetables, and whole-grain products
• Getting regular exercise, at least 30 minutes of moderate activity almost every day
• Losing weight so that your body mass index (BMI) is less than 25
• Managing blood pressure and blood sugar
• Not smoking
• Trying to include fish, preferably oily fish, in your diet at least twice a week

References

Lichtenstein AH, Appel LJ, Brands M, et al. Diet and lifestyle recommendations revision 2006: a scientific statement from the American Heart Association Nutrition Committee. Circulation. 2006;114:82-96.

Lakka T, Laaksonen DE. Physical activity in prevention and treatment of the metabolic syndrome. Appl Physiol Nutr Metab. 2007;32(1):76-88.

Grundy SM, Cleeman JI, Daniels SR, Donato KA, Eckel RH, Franklin BA, et al. American Heart Association; National Heart, Lung, and Blood Institute. Diagnosis and management of the metabolic syndrome: an American Heart Association/National Heart, Lung, and Blood Institute Scientific statement. Cardiol Rev. 2005;13:322-327.

Mahley RW, Weisgraber KH, Bersot TP. Disorders of Lipid Metabolism. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 36.