Metabolic syndrome is not, in and of itself, a disease. It is a term that was initially coined by the World Health Organization (WHO) in the late 1990s to identify people at a greater risk of developing cardiovascular disease (CVD).1  In essence, metabolic syndrome refers to a cluster of diseases that confer a cumulative risk for heart attack and stroke, providing health professionals with the ability to focus on prevention.

 
The original WHO definition of metabolic syndrome, also known as “syndrome X,” “insulin resistance syndrome” and “the deadly quartet,” required the patient to have one of the following: 2

  • Diabetes
  • Impaired glucose tolerance
  • Impaired fasting glucose
  • Insulin resistance

Plus two of the following:

  • A waist-to-hip ratio greater than 0.9 in men, 0.85 in women and/or a BMI greater than 30.
  • Dyslipidaemia (abnormal levels of fat/cholesterol in the blood)
  • Blood pressure of 140/90mmHg or higher
  • Microalbuminuria (increased levels of the protein albumin)

However, this was only one of a number of iterations of the definition of the syndrome. Consequently, the International Diabetes Federation (IDF) led a global conference to form consensus that was applicable to clinical practice. Currently, to be defined as having metabolic syndrome, a person must exhibit central obesity, as defined by waist circumference (with ethnic specific values), plus any two of the following:

  • High triglycerides
  • Reduced HDL cholesterol
  • Raised blood pressure
  • Increased fasting plasma glucose3

Globally, approximately 20-25% of adults have metabolic syndrome, making them three times as likely to have – and twice as likely to die from – a heart attack or stroke relative to their healthy peers. Additionally, people with metabolic syndrome have a five-fold greater risk of developing type 2 diabetes, which WHO expects will be the 7th leading cause of death in 2030. 4

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The above set of risk factors commonly appears together in people with glucose intolerance or type 2 diabetes, leading to a diagnosis of metabolic syndrome. The cardiovascular risk that these factors carry cumulatively is greater than simply their sum. 3

So what are the implications for a diagnosis of metabolic syndrome if it is not explicitly a disease in its own right? And what does that mean for treatment?

The definition itself is purely a diagnostic tool for health practitioners to identify patients who are at a higher risk of suffering a cardiac or stroke event. Treatment is aimed at controlling each individual factor associated with their diagnosis, primarily with lifestyle interventions.

The National Heart, Lung and Blood Institute recommends lifestyle changes including weight loss, maintenance of a heart-healthy diet, increased physical activity and cessation of smoking. Individuals for whom these changes are insufficient may be prescribed medications to treat each of the risk factors. 5

  1. Reaven, G.M. (2006) “The metabolic syndrome: is this diagnosis necessary?”, The American Journal of Clinical Nutrition, 83(6) (pp. 1237-1247)
  2. Alberti, K.G. & Zimmet, P.Z. (1998) “Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: diagnosis and classification of diabetes mellitus provisional report of a WHO consultation”, Diabetic Medicine, 15(7) (pp. 539-553)
  3. International Diabetes Federation (2006) “The IDF consensus worldwide definition of the Metabolic Syndrome”. Available at http://www.idf.org/metabolic-syndrome
  4. World Health Organization (2015) “Diabetes” Available at: http://www.who.int/mediacentre/factsheets/fs312/en/
  5. National Heart, Lung and Blood Institute (2011) “How Is Metabolic Syndrome Treated?” Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/ms/treatment