The metabolic syndrome: mechanisms, epidemiology, and clinical implications.

This article reviews the definition, mechanisms, epidemiology, and clinical sequelae of the metabolic syndrome and explores potential relationships between the metabolic syndrome, type 2 diabetes, and cardiovascular disease. Definitions for the metabolic syndrome proposed by the World Health Organization and the National Cholesterol Education Program of the National Heart Lung and Blood Institute, as well as proposed criteria for defining the syndrome in adolescents, are presented. Mechanisms that may be involved in the development of the metabolic syndrome--the role of obesity and visceral fat, insulin resistance, lipid abnormalities, chronic inflammation, and genetic factors--are discussed. Information on the epidemiology of the metabolic syndrome is reviewed, although the reported prevalence has varied widely due to the lack of a single accepted definition. This article also provides guidance concerning the evaluation and treatment of the metabolic syndrome, including the appropriate role of drug therapy in reducing the risk of diabetes and cardiovascular disease.