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Metabolic Syndrome

(Syndrome X; Insulin Resistance Syndrome)


Adrienne Youdim

, MD, David Geffen School of Medicine at UCLA

Reviewed/Revised Aug 2021 | Modified Sep 2022
Topic Resources

Metabolic syndrome is characterized by a large waist circumference (due to excess abdominal fat), hypertension, abnormal fasting plasma glucose or insulin resistance, and dyslipidemia. Causes, complications, diagnosis, and treatment are similar to those of obesity Obesity Obesity is excess body weight, defined as a body mass index (BMI) of ≥ 30 kg/m2. Complications include cardiovascular disorders (particularly in people with excess abdominal fat)... read more .

The incidence of metabolic syndrome often parallels that of obesity and type 2 diabetes. It is very common; in the US, > 40% of people > 50 years may have metabolic syndrome. Children and adolescents can develop metabolic syndrome, but in these age groups, no definition is established.

Development of metabolic syndrome depends on distribution as well as amount of fat. Excess fat in the abdomen (called apple shape), particularly when it results in a high waist-to-hip ratio (reflecting a relatively low muscle-to-fat mass ratio), increases risk. The syndrome is less common among people who have excess subcutaneous fat around the hips (called pear shape) and a low waist-to-hip ratio (reflecting a higher muscle-to-fat mass ratio).

Risks of metabolic syndrome include

Diagnosis of Metabolic Syndrome

  • Waist circumference and blood pressure

  • Fasting plasma glucose and a lipid profile

Screening for metabolic syndrome is important. A family history plus measurement of waist circumference and blood pressure are part of routine care. If patients with a family history of type 2 diabetes mellitus, particularly those 40 years, have a waist circumference greater than that recommended for their race and sex, fasting plasma glucose and a lipid profile must be determined.

Metabolic syndrome has many different definitions, but it is most often diagnosed when 3 of the following are present (see table Criteria Often Used for Diagnosis of Metabolic Syndrome Criteria Often Used for Diagnosis of Metabolic Syndrome* Criteria Often Used for Diagnosis of Metabolic Syndrome* ):


Treatment of Metabolic Syndrome

  • Healthy diet and exercise

  • Sometimes metformin

  • Management of cardiovascular risk factors

Optimally, the management approach results in weight loss based on a healthy diet and regular physical activity, which includes a combination of aerobic activity and resistance training, reinforced with behavioral therapy. Metformin, an insulin sensitizer, or a thiazolidinedione (eg, rosiglitazone, pioglitazone) may be useful. Weight loss of 7% may be sufficient to reverse the syndrome, but if not, each feature of the syndrome should be managed to achieve recommended targets; available drug treatment is very effective.

Other cardiovascular risk factors (eg, smoking cessation) also need to be managed. Increased physical activity has cardiovascular benefits even if weight is not lost.

Key Points

  • Excess abdominal fat leads to abnormal fasting plasma glucose or insulin resistance, dyslipidemias, and hypertension.

  • Metabolic syndrome is extremely common (eg, prevalence in the US of possibly > 40% in people > 50 years).

  • Determine waist circumference, blood pressure, fasting plasma glucose, and lipid profile.

  • Emphasize following a healthy diet and exercising and manage cardiovascular risk factors; if these measures are not completely effective, consider use of metformin.

Drugs Mentioned In This Article

Drug Name Select Trade
Afrezza, Exubera
Androderm, AndroGel, Andro-L.A., Aveed, AXIRON, Delatestryl, Depo-Testosterone, FORTESTA, JATENZO, KYZATREX, Natesto, STRIANT, Testim, Testoderm, Testopel, TLANDO, Virilon, Vogelxo, XYOSTED
Fortamet, Glucophage, Glucophage XR, Glumetza, Riomet, RIOMET ER
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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