Metabolic syndrome is not a disease. Rather, it is the name given to a collection of interrelated medical conditions that, together, drastically increase an individual’s risk of developing certain conditions, including:

• Type 2 diabetes. A metabolic condition in which the body is unable to use insulin properly or does not produce enough of this glucose-regulating hormone.
  
  
• Cardiovascular disease. A disease of the heart and blood vessels. In addition to raising the risk of heart conditions, metabolic syndrome can be a marker of undiagnosed atherosclerosis, even in apparently healthy young adults, according to recent research.
  
  
• Stroke. An event in which the flow of oxygen to the brain is suddenly interrupted.
  
  
• Fatty liver disease. A buildup of fat in the liver cells, which can lead to hepatitis and cirrhosis.

People with metabolic syndrome have a five-fold increased risk of developing type 2 diabetes (if not already present), three times the risk of heart or stroke, and double the risk of dying from heart attack or stroke, according to the International Diabetes Federation (IDF).

Because metabolic syndrome may develop long before these diseases materialize, identifying and treating this syndrome in its early stages can often help delay or prevent their onset.

Definitions of metabolic syndrome vary. The National Institutes of Health and the American Heart Association describe it as the presence of at least three of the following conditions:

• Abdominal obesity
• High blood pressure
• Insufficient HDL  “good” cholesterol
• Elevated triglycerides
• Elevated fasting glucose (prediabetes)

The IDF in 2006 released a consensus statement describing metabolic syndrome as culturally defined central obesity (specifying waist circumference of at least 94 centimeters [37 inches] for European men, 90 centimeters [35 inches] for Asian men, and 80 centimeters [32 inches] for European and Asian women), along with two of the following four factors:

• Elevated triglycerides: at least 150 milligrams per deciliter (mg/dL), or specific treatment for high triglycerides
  
  
• Reduced HDL cholesterol: less than 40 mg/dL in men or 50 mg/dL in women, or specific treatment for low HDL
  
  
• Raised blood pressure: systolic blood pressure of at least 130 millimeters of mercury (mm/Hg) or diastolic blood pressure of at least 85 mm/Hg, or treatment for previously diagnosed high blood pressure
  
  
• Elevated fasting glucose: at least 100 mg/dL, or previously diagnosed type 2 diabetes

Insulin resistance, which is closely related to prediabetes, is also commonly included as one of the possible factors in metabolic syndrome. Other contributors may include high levels of LDL “bad” cholesterol or VLDL “very bad” cholesterol, inflammation (increased C-reactive protein in the blood) or prothrombotic state.

Metabolic syndrome may also be called metabolic syndrome X, insulin resistance syndrome, dysmetabolic syndrome and Reavens syndrome. It affects one-fourth of the world’s population, according to the IDF. Metabolic syndrome is so closely associated with type 2 diabetes that many experts question whether diabetes should be added to the cluster of disorders that defines the condition.

Individuals at risk of developing metabolic syndrome should consult their primary care physician, who may recommend scheduling an appointment with an endocrinologist, a physician who specializes in treating hormonal and metabolism disorders.

The American Diabetes Association and the European Association for the Study of Diabetes issued a joint statement in 2005 that questioned the definition and even the existence of metabolic syndrome. They stated that the combination of conditions may not increase risk of complications any more than if these conditions were considered separately. Until further research shows a need to do otherwise, physicians should treat a patient’s various conditions and symptoms rather than diagnosing and treating a separate disease, the organizations suggested.

However, the IDF continues to offer guidelines for diagnosing and treating metabolic syndrome. It suggests moderate calorie restriction, diet and exercise as the primary intervention, with medications as the secondary intervention if these methods fail.