Metabolic syndrome

• What is Metabolic Syndrome?
• Statistics
• Risk Factors
• Progression
• Symptoms
• Clinical Examination
• How is it Diagnosed
• Prognosis
• Treatment
• References

What is Metabolic Syndrome?

Metabolic syndrome is diagnosed when a number of metabolic abnormalities (including insulin resistance and obesity) occur at the same time in an individual. Individuals who have the syndrome are more likely to develop cardiovascular disease and type 2 diabetes mellitus than those who do not. Metabolic syndrome is defined by the International Diabetes Federation as:

• Central obesity, indicated by a waist circumference (ethnicity specific)
• Plus any two of the following:
  1. Increased triglycerides
  2. Increased high density cholesterol
  3. High blood pressure
  4. High fasting plasma glucose

Statistics

Metabolic syndrome is an alarmingly common health condition, occurring in some 20–25% of the world’s population. In Australia, it is estimated that one in three people over the age of 25 years have the metabolic syndrome.

Risk Factors

Individuals who have a higher risk of developing metabolic syndrome include:

• Obese individuals, particularly those with obesity around their abdomen;
• Individuals consuming large amount of saturated fats;
• Individuals who consume more than one (in women) or two (in men) standard drinks of alcohol per day, or more than four (in women) or six (in men) standard drinks in a single session (commonly known as binge drinking) at least once a week;
• Individuals with schizophrenia are 2–4 times more likely to develop metabolic syndrome than non-schizophrenic individuals;
• Insulin resistant individuals;
• Individuals with a family history of insulin resistance and/or type 2 diabetes.

Progression

Unhealthy eating habits and lack of physical activity are the key lifestyle factors leading to metabolic syndrome. Extended periods of unhealthy eating and limited physical activity result in obesity and insulin resistance, which in turn affect the body’s metabolism and increase the risk of metabolic syndrome. Once metabolic syndrome is diagnosed, the syndrome is likely to worsen. If left untreated, individuals may go on to develop additional metabolic abnormalities. In addition, once metabolic syndrome is diagnosed, other metabolic abnormalities (e.g. abnormal blood pressure response to changes in dietary salt) also tend to worsen.

Symptoms

Individuals diagnosed with metabolic syndrome are up to three times more likely to develop cardiovascular health problems, and up to five times more likely to develop type 2 diabetes, than individuals who do not have metabolic syndrome.

Clinical Examination

If a doctor suspects a patient to have metabolic syndrome, they will likely measure the patient’s waist to assess central obesity (alternatively, a body mass index > 30 also indicates obesity).  If central obesity is diagnosed, further investigations may be undertaken to assess blood pressure and glucose, triglyceride and cholesterol levels.

How is it Diagnosed

Patients are diagnosed with metabolic syndrome if their waist circumference measure shows that they are centrally obese and their test results show at least two metabolic abnormalities.

Prognosis

While many individuals with metabolic syndrome go on to develop type 2 diabetes and CVD, the condition can be resolved through diet and lifestyle changes. Early intervention increases the chances of successful treatment. Individuals with metabolic syndrome may also develop conditions associated with diabetes, even if they do not receive a diabetes diagnosis. For example individuals with metabolic syndrome may develop diabetic retinopathy.

Treatment

The treatment of metabolic syndrome generally focuses on diet and exercise therapy. To reverse the metabolic abnormalities of metabolic syndrome, regular physical activity and a diet with a restricted calorie intake, that is high in whole grains, monounsaturated fats and plant foods (such as the Mediterranean diet), are recommended.

Click here to watch a video on diet and the metabolic syndrome.

If diet and exercise interventions fail to regulate metabolic abnormalities, doctors may provide medications to reduce blood pressure or cholesterol levels.  A comprehensive approach to the management of metabolic syndrome, including diet, exercise and medication for metabolic abnormalities, is known as the ABCDE approach. This stands for:

• A: Assessment of cardiovascular risk and aspirin therapy
• B: Blood pressure control
• C: Cholesterol management
• D: Diabetes prevention and diet therapy
• E: Exercise therapy

 
Overview of medical treatment of metabolic syndrome
There are currently no medications available that treat all the metabolic abnormalities of metabolic syndrome together. If a doctor prescribes medications to treat metabolic syndrome, they will prescribe specific medications to treat each abnormality separately.
Aspirin therapy is the most common treatment to reduce the risk of cardiovascular diseases, while angiotension-converting enzyme (ACE) inhibitors and angiotension receptor blockers (ARBs) are likely to be prescribed for patients requiring blood pressure control. Fibrates and statins are recommended for cholesterol control.

Assessment of cardiovascular risk and aspirin therapy
The doctor will assess the risk of cardiovascular disease, by using the Framingham risk score. When the Framingham risk score indicates a risk of cardiovascular disease greater than 5%, the doctor will probably recommend daily doses of aspirin to correct the problem. While aspirin does not require a prescription and is commonly used for dealing with fevers and headaches, individuals should always consult a doctor before taking aspirin on a daily basis. This is because daily consumption of aspirin can result in dangerous bleeding in some individuals.

Blood pressure control
Medications for blood pressure control may be prescribed for patients with metabolic syndrome and a blood pressure higher than 130/80 mmHg.  The most commonly prescribed medications are ACE inhibitors and ARBs.

Cholesterol management
There are two types of cholesterol in the body: low density lipoprotein cholesterol (LDL-C or bad cholesterol); and high density lipoprotein cholesterol (HDL-C or good cholesterol).  The goal of cholesterol management is to reduce levels of LDL-C and increase levels of HDL-C.

Diabetes prevention and diet therapy
Losing weight by eating less high fat foods is very important for individuals who have metabolic syndrome. It can reduce the risk of developing type 2 diabetes and may also reduce the risk of coronary heart disease.
For individuals with metabolic syndrome, reducing total calorie intake is important. However, eating the correct combination of foods is also very important.
Dietary modifications
Diets low in saturated fats (e.g. fat derived from animals), red meat and sugar, but high in monounsaturated fats (e.g. olive oil), fresh fruits, vegetables and whole grains, provide the greatest health benefit for individuals with metabolic syndrome (and individuals who wish to prevent metabolic syndrome). This nutritional combination is typical of a Mediterannean diet.

Exercise therapy
Increased physical activity increases weight loss and decreases the risk of diabetes and coronary heart disease. Exercise is therefore a very important component of any treatment for metabolic syndrome treatment.
At least 30 minutes of moderate intensity exercise per day is recommended for general health. Walking is a particularly good form of exercise and individuals with metabolic syndrome should try to walk more (e.g. to work or the shops, with friends or children).

More information

For more information on fitness and exercise, including stretches, types of exercise, exercise recovery and exercise with health conditions, as well as some useful videos, see Fitness.

For more information on nutrition, including information on types and composition of food, nutrition and people, conditions related to nutrition, and diets and recipes, as well as some useful videos and tools, see Nutrition.

For more information on obesity, health and social issues, and methods of weight loss, as well as some useful tools, see Weight Loss.

References

1. International Diabetes Federation. The IDF consensus worldwide definition of the metabolic syndrome [online]. 4 September 2006 [cited 26 September 2008]. Available from: URL link
2. World Health Organization. Definition, diagnosis and classification of diabetes mellitus and its complications. Report of a WHO consultation, Part 1: Diagnosis and classification of diabetes mellitus, Geneva, 59p, WHO/NCD/NCS/99.2 [online]. 1999 [cited 26 September 2008]. Available from: URL link
3. Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive summary of the third report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA. 2001;285(19):2486-97. [Abstract]
4. Alberti KG, Zimmet P, Shaw J. The metabolic syndrome: A new worldwide definition. Lancet. 2005;366:1059-62. [Abstract]
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8. Saari KM, Lindeman SM, Viilo KM, Isohanni MK, Järvelin MR, et al. A 4 fold risk of metabolic syndrome in patients with schizophrenia: The Northern Finland 1966 Birth Cohort Study. J Clin Psychiatry. 2005;66(5):559-63. [Abstract]
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10. Blaha MJ, Bansal S, Rouf R, Golden SH, Blumenthal RS, Defilippis AP. A practical “ABCDE” approach to the metabolic syndrome. Mayo Clin Proc. 2008;83(8):932-41. [Abstract | Full text]
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