Current understanding of multiple risk factors as the metabolic syndrome: distillation or deconstruction

The "metabolic syndrome" is a new term that defines the clustering of vascular risk factors, such as hyperlipidemia, obesity, elevated blood pressure, and elevated blood glucose. Controversy exists regarding the use of the term, which raises the question of whether the unique grouping of vascular risk factors adds more clinical risk then the additive effect of multiple risk factors viewed as separate but important entities. Whatever the answer, the metabolic syndrome constitutes a major public health problem with over 47 million persons in the United States meeting criteria for the metabolic syndrome. Although studies have demonstrated that the metabolic syndrome is a risk factor for overall mortality as well as cardiovascular events, the relationship between the metabolic syndrome and ischemic stroke has not been well characterized. Two large cross-sectional studies report an association between metabolic syndrome and increased risk of a history of stroke. One large multiethnic prospective study found the metabolic syndrome to be significantly associated with an increased risk of ischemic stroke after adjustment for sociodemographics and other cardiovascular risk factors. This study estimated that the metabolic syndrome may account for 19% of ischemic strokes including 30% of stroke in women and over 40% of stroke in Hispanics. Despite debate about the utility of its definition, there is evidence to suggest that the metabolic syndrome is an important risk factor for ischemic stroke, with differential effects by gender and race-ethnicity. Further, the metabolic syndrome has important clinical and public health implications by helping to easily identify individuals at greatest risk of vascular events.