[Metabolic syndrome: which définition(s) for which objective(s)?]

Several definitions are currently proposed to define metabolic syndrome (WHO, EGIR, NCEP-ATP III, AACE). The interest and the drawbacks of these definitions, as well as the "hypertriglyceridemic waist" phenotype proposed by Canadian authors, are described. All observational studies indicate an increased cardiovascular morbidity and mortality risk, and likely a type 2 diabetes increased risk, in individuals with metabolic syndrome. Therefore, it is justified to identify these individuals in order to implement preventive or therapeutic measures, and to be able to evaluate the intervention results. Use of any metabolic syndrome definition should be driven by the objective: either epidemiological studies, or clinical trials or assessment of intervention programs, or public health campaigns, or clinical management of at-risk individuals. The rationale for choosing one of these definitions is discussed on the basis of recent publications.