Historical perspectives of the metabolic syndrome.

The metabolic syndrome (MetS) or insulin resistance syndrome is a constellation of obesity-related metabolic derangements predisposing to type 2 diabetes and cardiovascular disease. In 1998, WHO defined the first criteria of MetS. Three years later, the user-friendly National Cholesterol Education Program criteria of MetS were proposed. Different criteria were issued by the International Diabetes Federation in 2005, making abdominal obesity a necessary component. Several international societies, including The International Diabetes Federation, jointly adopted the revised National Cholesterol Education Program criteria as harmonizing criteria of MetS in 2009. WHO warned the next year that MetS has limited practical utility as a management tool. Adipose tissue inflammation has been shown to be a fundamental mechanism of metabolic derangements, associated with ectopic lipid deposit and mitochondrial dysfunction in skeletal muscle and the liver.