Background and Purpose—Limited information is available on the role of the metabolic syndrome (MetS) to predict stroke. We investigated the relationship of the MetS and its single components, defined by 6 different criteria, with stroke in a prospective population-based study.

Methods—The MetS was defined according to the World Health Organization, the European Group for the Study of Insulin Resistance, the National Cholesterol Education Program (NCEP), the American College of Endocrinology, the International Diabetes Federation, and the American Heart Association (updated NCEP) criteria. We investigated the relationship of the MetS with stroke using Cox regression analyses in 991 Finnish subjects without diabetes, aged 65 to 74 years at baseline, and followed-up for 14 years.

Results—The MetS defined by the World Health Organization, European Group for the Study of Insulin Resistance, NCEP, International Diabetes Federation, and updated NCEP criteria was significantly associated with incident stroke (fatal and nonfatal) when adjusted for confounding variables (HR, 1.52 to 1.72). After exclusion of subjects with myocardial infarction, these 5 definitions still predicted stroke (HR, 1.49 to 1.80). Of the single components of the MetS, the following predicted stroke in multivariable models when subjects with myocardial infarction were excluded: impaired glucose tolerance (2-hour glucose in an oral glucose tolerance test, 7.8 to 11.0 mmol/L) by the World Health Organization and American College of Endocrinology criteria (HR, 1.66); insulin resistance (HR, 1.60) by the European Group for the Study of Insulin Resistance criteria; and central obesity (HR, 1.52) by the NCEP criteria.

Conclusions—The MetS defined by the 6 criteria except for the American College of Endocrinology definition predicts stroke in elderly subjects. However, impaired glucose tolerance alone is as strong a predictor of stroke as is the MetS defined by the World Health Organization, NCEP and updated NCEP criteria.