[The metabolic syndrome. Part I: definitions and diagnostic criteria for its identification. Epidemiology and relationship with cardiovascular and type 2 diabetes risk].

The term metabolic syndrome (MS) refers to a clustering of risk factors of metabolic origin that promote the development of cardiovascular disease and type 2 diabetes. Metabolic syndrome includes such pathological factors as insulin resistance, hyperinsulinemia, abdominal obesity, impaired glucose tolerance, type 2 diabetes, microalbuminuria, high level of triglycerides, low level of HDL cholesterol, elevated blood pressure, and proinflammatory and prothrombotic state. Several organizations have recommended clinical criteria for the diagnosis of metabolic syndrome. The most widely accepted were the worked out by the World Health Organization (WHO), the European Group for the Study of Insulin Resistance (EGIR), and the National Cholesterol Education Program--Third Adult Treatment Panel (NCEP-ATP III). In 2005, IDF experts proposed a universally accepted diagnostic tool that is easy to use in clinical practice and does not rely on measurements available only in research settings. All groups agreed on the core components of the metabolic syndrome: obesity, insulin resistance, dyslipidemia, and hypertension. Their criteria are similar in many aspects, but they also reveal fundamental differences in their positioning of the predominant causes of the syndrome. This study provides a brief overview of current definitions of metabolic syndrome, with particular reference to the differences between them, and presents critical remarks on the concept of metabolic syndrome and its usefulness. It also presents epidemiological data which consider metabolic syndrome and its association with increased risk of cardiovascular disease and type 2 diabetes.