Paul Zimmet
International Diabetes Institute, Melbourne, Australia

The immediate response to this question must be a resounding "Yes!!". The Metabolic Syndrome is now one of the major threats to human health. With the explosive increase in the number of people with diabetes globally, there is the foundation for a cardiovascular disease (CVD) epidemic of huge proportions. It has become increasingly evident that type 2 diabetes, impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) cannot be viewed in isolation as totally discrete states. Many individuals with these conditions exhibit clustering of a number of CVD risk factors which, apart from glucose intolerance, include hyperinsulinaemia/insulin resistance, hypertension, central (abdominal) obesity, and dyslipidaemia. Indeed, 80% of people with type 2 diabetes, and 50% of those with IGT and/or IFG, have Metabolic Syndrome, and this group is at very high risk of macrovascular disease.

The basic elements of Metabolic Syndrome were first described over 40 years ago by J. Vague. In 1988, G. Reaven refocussed attention on the cluster and proposed the name “Syndrome X”. He suggested that insulin resistance with its consequent hyperinsulinaemia was the underlying abnormality. As it is more usual to have central obesity as part of the cluster, the term "Metabolic Syndrome" is now favoured. Nevertheless, Reaven stimulated a significant renewal of interest in not only the aetiology of the cluster, but also the importance of aggressively treating the other CVD risk factors in type 2 diabetes. Epidemiological studies indicate that Metabolic Syndrome occurs commonly in a number of ethnic groups including Europeans, Asian Indians and Chinese, Australian Aborigines, Afro-Americans, Mexican-Americans and Polynesians and Micronesians. The rates of CVD are on the rise in each of these populations. This combination of risk factors is largely responsible for the increased risk of CVD in people with diabetes. This new recognition of the association of type 2 diabetes with Metabolic Syndrome has led to a new paradigm relating to type 2 diabetes therapy. Evidence now exists for a far more aggressive approach to treating not just hyperglycaemia, but also the other CVD risk factors such as hypertension, dyslipidaemia, and central obesity in type 2 diabetic patients. The hope is that there will be a significant reduction in cardiovascular morbidity and mortality.

WHO’s 1999 report, "Definition, Diagnosis and Classification of Diabetes Mellitus and its Complications-Part 1: Diagnosis and Classification of Diabetes Mellitus", highlighted the need for a consistent definition of Metabolic Syndrome and suggested parameters. This need is even more urgent for other definitions such as the Adult Treatment Panel III (ATP-III) guideline recommendations. While the criteria may change as new prospective data become available, the WHO initiative provides a basis for developing a standardised definition for international comparisons of prevalence, incidence, and natural history, whereas previously there was no internationally agreed definition.