Metabolic Syndrome, Insulin Resistance, and Brachial Artery Vasodilator Function in Framingham Offspring Participants Without Clinical Evidence of Cardiovascular Disease

The metabolic syndrome (MS), a clustering of metabolic disturbances, is associated with increased cardiovascular risk. Limited information is available about the relations between MS, insulin resistance, and vascular function. We measured brachial artery flow-mediated dilation (n = 2,123) and reactive hyperemia (n = 1,521) in Framingham Offspring participants without diabetes or clinical cardiovascular disease (mean age 59 ± 9 years, 57% women). MS, determined by National Cholesterol Education Program criteria, was present in 36% of participants. Insulin resistance was determined using Homeostatic Model Assessment. In age- and gender-adjusted models, MS was associated with lower flow-mediated dilation and reactive hyperemia. There was progressively lower vasodilator function with increasing number of MS components (p for trend