Metabolic Syndrome

(Syndrome X; Insulin Resistance Syndrome; Dysmetabolic Syndrome)

by Amy Scholten, MPH

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Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

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Related Media: Metabolic Syndrome—Reducing Your Risk Factors

 

What Is Metabolic Syndrome?

 

Definition

Metabolic syndrome is a group of risk factors for cardiovascular disease. The factors are related to the breakdown and use of food and the action of the hormone insulin. These conditions are risk factors for health issues, such as:

• Type 2 diabetes
• Coronary artery disease
• Stroke
• Peripheral vascular disease

In general, metabolic syndrome is characterized by:

• Abdominal obesity—high amount of fat around the waist
• High cholesterol
• High blood pressure
• Insulin resistance (glucose intolerance or prediabetes)—insulin helps move glucose out of the blood into cells; if a resistance develops it will increase the amounts of blood glucose

 

Causes

The exact cause of metabolic syndrome is not known. It believed to be due to a combination of factors, such as:

• Genetic factors
• Insulin resistance
• Obesity (especially central obesity)
• Lack of physical activity
• Poor diet
• Fatty tissue abnormalities linked to insulin resistance and obesity
• Psychological stress
• Chronic low-grade inflammation
• Aging

 

Risk Factors

Risk factors for metabolic syndrome may include the following:

• Overweight (especially excessive fat in the abdominal region)
• Poor diet
  • Eating a diet high in calories, sugar, saturated fats, and starchy foods (eg, bread, cereal, rice, pasta, potatoes), and low in dietary fiber
  • Drinking a lot of soda, even diet soda, has been linked to metabolic syndrome
• Sedentary lifestyle
• Gender
  • No difference in Caucasians
  • African Americans: females more than males by 57%
  • Mexican Americans: females more than males by 26%
• Genetics: family history of diabetes, lipid disorders, high blood pressure, or heart disease
• Socioeconomic factors: low income
• Age: over 60 years old
• Ethnicity: Latino/Hispanic American, African American, Native American, Asian American, Pacific Islander
• History of glucose intolerance or gestational diabetes
• A diagnosis of any of the following conditions:
  • High blood pressure
  • Elevated triglycerides/low HDL-cholesterol
  • Cardiovascular disease
  • Polycystic ovary syndrome
  • Acute pancreatitis
  • Chronic kidney disease

 

Symptoms

Except for obesity, there are no obvious symptoms. The following symptoms are associated with obesity:

• Sleep apnea
• Back or knee pain
• Shortness of breath
• Reduced exercise tolerance
• Fatigue
• Central obesity
• Elevated blood pressure

 

Diagnosis

The doctor will ask about your medical history. A physical exam will be done. Your doctor may order lab tests. such as:

• Blood tests to measure:
  • Glucose levels
  • Hemoglobin A1c
  • Insulin levels
  • Triglyceride level
  • Cholesterol levels
  • C reactive protein
• Blood pressure
• Calculation of body mass index (BMI)
• Measurement of waist circumference
• Calculation of 10-year risk of cardiovascular disease

According to the National Heart Lung and Blood Institute, you may be diagnosed with metabolic syndrome if you have at least three of the following:

• Waist measurement—greater than 40 inches in Caucasian men (35 inches in Asian men) or 35 inches in Caucasian women (30 inches in Asian women)
• Fasting glucose level—greater than or equal to 100 mg/dL* (5.55 mmol/L)
• Triglyceride level—greater than or equal to 150 mg/dL (1.7 mmol/L)
• HDL (“good”) cholesterol—less than 40 mg/dL (1.0 mmol/L) in men and less than 50 mg/dL (1.3 mmol/L) in women
• Blood pressure—greater than or equal to 130/85 millimeters of mercury (mm Hg)

*mg/dL = milligrams per deciliter blood, mmol/L = millimoles per liter blood

 

Treatment

The treatment of metabolic syndrome involves:

• Treatment of underlying causes
• Treatment of specific metabolic abnormality

 

Prevention

To help prevent metabolic syndrome:

• Achieve and maintain a healthy weight.
• Do 30 minutes of moderate aerobic exercise at least four days per week.
• See your doctor regularly.

In addition, other unhealthy lifestyle factors also contribute to heart disease, stroke, and peripheral vascular disease. To lower your risk of these diseases:

• Eat a healthy diet. It should be low in saturated and trans fats. Also keep it low in cholesterol. Aim for a diet that is rich in whole grains, fruits, and vegetables. Avoid soda. Ask your doctor if the Mediterranean diet is right for you.
• If you smoke, quit. Smoking increases cardiovascular risk
• Drink alcohol in moderation. This means no more than two drinks daily for men, one drink daily for women.

 RESOURCES:

American Heart Association
http://www.americanheart.org/

National Institute of Diabetes & Digestive & Kidney Diseases
http://www.niddk.nih.gov/

 CANADIAN RESOURCES:

Canadian Cardiovascular Society
http://www.ccs.ca/home/index_e.aspx/

Canadian Diabetes Association
http://www.diabetes.ca/

REFERENCES:

Cornier MA, Dabelea D, Hernandez TL, et al. The metabolic syndrome. Endocr Rev. 2008;29:777-822.

Deen D. Metabolic syndrome: time for action. Am Fam Physician. 2004;69:2875-2882.

Eckel RH, Grundy SM, Zimmet PA. The metabolic syndrome. Lancet . 2005;365:1415-1428.

Findings and recommendations from the American College of Endocrinology on the insulin resistance syndrome. American Association of Clinical Endocrinologists website. Available at: http://www.aace.com. Accessed January 31, 2010.

Gami AS, Witt BJ, Howard DE, et al. Metabolic syndrome and risk of incident cardiovascular events and death. J Am Coll Cardiol . 2007;49:403-414.

Grundy SM, Brewer HB, Cleeman JI, et al. Definition of metabolic syndrome: report of the NHLBI/AHA conference on scientific issues related to definition. Circulation . 2004;109:433-438.

Grundy SM, Cleeman JI, Diniels SR, et al. AHA/NHLBI Diagnosis and management of the metabolic syndrome: an AHA/NHLBI Scientific Statement. Circulation . 2005;112:2735-2752.

Metabolic syndrome. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated May 2009. Accessed May 18, 2009.

National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov .

National Institute of Diabetes & Digestive & Kidney Diseases website. Available at: http://www.niddk.nih.gov.

Reaven GM. The metabolic syndrome or the insulin resistance syndrome? Different names, different concepts, and different goals. Endocrinol Metab Clin North Am. 2004;33:283-304.

Steinberger J, Daniels SR, Eckel RH, et al. AHA scientifc statement: progress and challenges in metabolic syndrome in children and adolescents. Circulation. 2009;119:628-647.

Syndrome X or metabolic syndrome. American Heart Association website. Available at: http://www.americanheart.org . Accessed January 17, 2003.

Wright JT, Harris-Haywood S, Pressel S, et al. Clinical outcomes by race in hypertensive patients with and without the metabolic syndrome (ALLHAT). Arch Int Med. 2008;168:207-217.

1/13/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: Salas-Salvadó J, Fernández-Ballart J, Ros E, et al. Effect of a Mediterranean diet supplemented with nuts on metabolic syndrome status: one-year results of the PREDIMED randomized trial. Arch Intern Med. 2008;168:2449-2458.

2/17/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Davidson LE, Hudson R, Kilpatrick K, et al. Effects of exercise modality on insulin resistance and functional limitation in older adults: a randomized controlled trial. Arch Intern Med. 2009;169:122-131.

5/11/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Nettleton JA, Lutsey PL, Wang Y, Lima JA, Michos ED, Jacobs DR. Diet soda intake and risk of incident metabolic syndrome and type 2 diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA). Diabetes Care. 2009;32:688-694.

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Last reviewed February 2010 by B. Gabriel Smolarz, MD
Last Updated: 2/4/2010