The IDF consensus worldwide de nition of the METABOLIC SYNDROME No part of this publication may be reproduced or transmitted in any form or by any means without the prior written permission of the International Diabetes Federation (IDF). Requests to reproduce or translate IDF publications should be addressed to: IDF Communications Avenue Emile De Mot 19, B-1000 Brussels, Belgium by fax at +32-2-5385114 or by e-mail at [email protected] © International Diabetes Federation, 2006 2 The IDF worldwide defi nition of the metabolic syndrome was developed during a unique consensus workshop on the initiative of Professors Sir George Alberti and Paul Zimmet. The workshop was held on behalf of the IDF Task Force on Epidemiology and Prevention. After the meeting, a writing group was convened including: Sir George Alberti, London, UK Paul Zimmet, Melbourne, Australia Jonathan Shaw, Melbourne, Australia Scott M. Grundy, Dallas, USA, Consultant to Writing Group The IDF metabolic syndrome consensus defi nition process (workshop) was supported by an educational grant from AstraZeneca Pharmaceuticals. AstraZeneca had no role in the development of the consensus defi nition, or in the review or approval of the manuscript. This publication has been funded by IDF. The IDF also gratefully acknowledges the contribution of: Pablo Aschner - Bogotá, Columbia Beverley Balkau - France Philip Barter - Sydney, Australia Peter Bennett - Phoenix, USA Edward Boyko - Seattle, USA John Brunzell - Seattle, USA Juliana Chan - Hong Kong, SAR China Ralph DeFronzo - San Antonio, USA Jean-Pierre Després - Québec, Canada Leif Groop - Lund, Sweden Markku Laakso - Kuopio, Finland Pierre Lefèbvre - Liège, Belgium Yuji Matsuzawa - Osaka, Japan Jean Claude Mbanya - Yaounde, Cameroon Chang Yu Pan - Beijing, China Ambady Ramachandran - Chennai, India Eberhard Standl - Munich, Germany Michael Stern - San Antonio, USA Jaakko Tuomilehto - Helsinki, Finland Nigel Unwin - Geneva, Switzerland Colette Kon, Rapporteur IDF Executive Offi ce: Anne Pierson 3 The metabolic syndrome © Tihis | Dreamstime.com The metabolic syndrome is a cluster In addition, people with metabolic of the most dangerous heart attack syndrome have a fi vefold greater risk factors: diabetes and raised risk of developing type 2 diabetes.5 fasting plasma glucose, abdominal They would add to the 230 million obesity, high cholesterol and high people worldwide who already have blood pressure.1-4 diabetes6a, one of the most common chronic diseases worldwide and It is estimated that around 20-25 per the fourth or fi fth leading cause of cent of the world’s adult population death in the developed world. The have the metabolic syndrome and clustering of cardiovascular disease they are twice as likely to die from (CVD) risk factors that typifi es and three times as likely to have a the metabolic syndrome is now heart attack or stroke compared considered to be the driving force for with people without the syndrome. a new CVD epidemic. 4 Diabetes and the metabolic syndrome– driving the CVD epidemic Each year, 3.2 million people around what is now known as the ‘Metabolic the world die from complications Syndrome’. This ‘clustering’ of associated with diabetes. In countries metabolic abnormalities that occur with a high diabetes incidence, such in the same individual appear to as those in the Pacifi c and the Middle confer a substantial additional East, as many as one in four deaths cardiovascular risk over and above in adults aged between 35 and 64 the sum of the risk associated with years is due to the disease. Type 2 each abnormality.8,9 diabetes, which accounts for 90 per cent of all diabetes, has become one However, even before levels of of the major causes of premature blood glucose are high enough illness and death, mainly through for a person to be diagnosed with the increased risk of CVD which is diabetes, hyperglycaemia and related responsible for up to 80 per cent of changes in blood lipids (increase in these deaths.6b,7 triglycerides and decrease in the ‘good’ cholesterol HDL-c) increase In most people with glucose a person’s risk of CVD.8 The more intolerance or type 2 diabetes, there components of the metabolic is a multiple set of risk factors that syndrome that are evident, the higher commonly appear together, forming is the cardiovascular mortality rate.10 5 Global burden The cardiovascular complications of The annual direct healthcare cost diabetes, which is also a leading cause of diabetes worldwide for this age of blindness, amputation and kidney group is conservatively estimated failure, account for much of the social to be as much as 286 billion ID, or and fi nancial burden of the disease.11 even more. If diabetes prevalence The prediction that diabetes incidence continues to rise as anticipated, it is will double by 2025 indicates a parallel likely that this fi gure will increase to rise in cardiovascular-related illness and 396 billion ID by 2025. This will mean death, with an inevitable and profound an expenditure of up to 13 per cent impact on global healthcare systems. of the world’s healthcare budget on diabetes care, with high prevalence With a rise in comorbid disease on countries spending up to 40 per cent this scale, the burden on national of their budget.6b healthcare systems and budgets is enormous. It was estimated that It is important to note that these in 2003 for the 25 European Union estimates of burden on national countries the total direct healthcare healthcare systems are for type 2 costs of all diabetes in 20 to 79 diabetes only and do not, as yet, year olds was up to 64.9 billion estimate the additional burden of international dollars (ID), equivalent CVD associated with metabolic to 7.2 per cent of the total health syndrome where clinical diabetes is expenditure for these countries.6b,12 not yet present. 6 What causes the metabolic syndrome? The underlying cause of the much glucose in the blood) and will metabolic syndrome continues to be diagnosed with type 2 diabetes. challenge the experts but both insulin Even before this happens, damage resistance and central obesity are is occurring to the body, including a considered signifi cant factors.13,14 build-up of triglycerides which further Genetics, physical inactivity, ageing, a impairs insulin sensitivity. proinfl ammatory state and hormonal changes may also have a causal Central obesity effect, but the role of these may vary Obesity is associated with insulin depending on ethnic group.15,16 resistance and the metabolic syndrome. Obesity contributes to Insulin resistance hypertension, high serum cholesterol, Insulin resistance occurs when cells low HDL-c and hyperglycaemia, and is in the body (liver, skeletal muscle independently associated with higher and adipose/fat tissue) become less CVD risk.13,17,18 The risk of serious sensitive and eventually resistant health consequences in the form to insulin, the hormone which of type 2 diabetes, coronary heart is produced by the beta cells in disease (CHD) and a range of other the pancreas to facilitate glucose conditions, including some forms absorption. Glucose can no longer of cancer, has been shown to rise be absorbed by the cells but with an increase in body mass index remains in the blood, triggering (BMI),19 but it is an excess of body fat the need for more and more insulin in the abdomen, measured simply (hyperinsulinaemia) to be produced by waist circumference, that is more in an attempt to process the glucose. indicative of the metabolic syndrome The production of ever-increasing profi le than BMI.20-22 The International amounts of insulin weakens and may Obesity Task Force (IOTF) reports that eventually wear out the beta cells. 1.7 billion of the world’s population Once the pancreas is no longer able is already at a heightened risk of to produce enough insulin then a weight-related, non-communicable person becomes hyperglycaemic (too diseases such as type 2 diabetes.23 7 The need for early diagnosis and treatment: the IDF worldwide de nition of metabolic syndrome With the metabolic syndrome driving Furthermore, the existence of the twin global epidemics of type 2 multiple defi nitions for the metabolic diabetes and CVD there is an syndrome has caused confusion overwhelming moral, medical and and has resulted in many studies economic imperative to identify those and research papers comparing individuals with metabolic syndrome the merits of each defi nition. It has early, so that lifestyle interventions also proved diffi cult to make direct and treatment may prevent the comparisons between the data from development of diabetes and/or studies where different defi nitions cardiovascular disease. have been used to identify the syndrome. A number of expert groups have developed clinical criteria for the IDF experts recognized that there was metabolic syndrome. The most widely a stark need for a single, universally accepted of these were produced by the accepted diagnostic tool that is easy World Health Organization (WHO), the to use in clinical practice and that European Group for the Study of Insulin does not rely upon measurements Resistance (EGIR), and the National only available in research settings. Cholesterol Education Program – Third Adult Treatment Panel (NCEP ATP The new IDF defi nition addresses III).24-26 All groups agreed on the core both clinical and research needs, components of the metabolic syndrome: providing an accessible, diagnostic obesity, insulin resistance, dyslipidaemia tool suitable for worldwide use and hypertension. However, the existing and establishing a