Metabolic syndrome is characterized by a large waist circumference (due to excess abdominal fat), high blood pressure, resistance to the effects of insulin (insulin resistance) or diabetes, and abnormal levels of cholesterol and other fats in the blood (dyslipidemia).

Excess abdominal fat increases the risk of high blood pressure, coronary artery disease, and type 2 diabetes.

To diagnose metabolic syndrome, doctors measure waist circumference, blood pressure, and fasting blood sugar and fat (lipid) levels.

Exercise, changes in eating habits, behavioral techniques, and drugs may be used to help people lose weight.

Diabetes, high blood pressure, and abnormal blood cholesterol and fat levels are treated.

Metabolic syndrome is a serious problem. In the United States, more than 40% of people over 50 may have it. Even children and adolescents can develop metabolic syndrome, but how many have it is unknown.

Metabolic syndrome is more likely to develop when people store excess fat in the abdomen (apple-shaped) rather than around the hips (pear-shaped). The following people tend to store excess fat in the abdomen:

Most men

Women after menopause

Storing excess fat in the abdomen increases the risk of the following

Coronary artery disease

High blood pressure

Type 2 diabetes

Abnormal levels of fats, including cholesterol, in the blood (dyslipidemia)

Fatty liver

Gout

Polycystic ovary syndrome (in women)

Chronic kidney disease

Obstructive sleep apnea

Erectile dysfunction (in men)

Metabolic syndrome itself causes no symptoms.

(See also Obesity.)

Diagnosis of Metabolic Syndrome

Waist circumference

Blood pressure measurement

Blood tests to measure sugar and fat (lipid) levels

Waist circumference should be measured in all people because even people who are not overweight or appear lean can store excess fat in the abdomen. The greater the waist circumference, the higher the risk of metabolic syndrome and its complications. The waist circumference that increases risk of complications due to obesity varies by ethnic group and sex.

If waist circumference is high, doctors should measure blood pressure and blood sugar and fat levels after fasting. Levels of both blood sugar and fats are often abnormal.

Metabolic syndrome has many different definitions, but it is most often diagnosed when the waist circumference is 40 inches (102 centimeters) or more in men or 35 inches (88 centimeters) or more in women (indicating excess fat in the abdomen) and when people have or are being treated for two or more of the following:

A fasting blood sugar level of 100 mg/dL (milligrams per deciliter) or higher

Blood pressure of 130/85 mm Hg (millimeters of mercury) or higher

A fasting blood triglyceride (a fat) level of 150 mg/dL or higher

A high density lipoprotein (HDL—the good) cholesterol level of less than 40 mg/dL for men or less than 50 mg/dL for women