Abstract 3119: Insulin Resistance is Associated with Impaired Flow-mediated Vasodilatation in a Multi-ethnic Population: The Northern Manhattan Study
Background: Metabolic abnormalities, including diabetes mellitus, are associated with impaired endothelial function. However, the relationship between endothelial function and glucose metabolism has not been thoroughly investigated.
Aim: We tested the hypothesis that insulin resistance is associated with impaired flow-mediated vasodilatation (FMD) in a population-based multi-ethnic cohort.
Methods: As part of the Northern Manhattan Study, we measured fasting insulin levels and FMD during reactive hyperemia by high-resolution ultrasonography in 601 community participants without diabetes. General linear models were used to test the association of fasting insulin, as a surrogate maker of insulin resistance (IR), with FMD after adjusting for age, sex, race-ethnicity, waist circumference, systolic blood pressure, high-density lipoprotein cholesterol, smoking, and fasting glucose. Mean FMD was also compared among the following three subgroups: normal fasting glucose (NFG) with IR (NFG*IR+), NFG without IR (NFG*IR−), and impaired fasting glucose (IFG). IR was defined as the upper quartile of homeostasis model index of insulin resistance (HOMA-IR).
Results: The mean age was 66±9 years; 43% were male, 15% white, 16% black, and 68% Hispanic. The mean HOMA-IR was 2.45±1.88. In multiple linear regression analyses, fasting insulin was inversely correlated with FMD (β= −0.05, SE=0.02, p=0.032), after adjustment for other covariates. Race-ethnicity was not a significant modifier of the association of fasting insulin with FMD. The mean FMD was greatest in NFG*IR− even after adjustment [FMD (95% CI) 6.28 (5.91– 6.64) for NFG*IR−, 5.21 (4.43–5.99) for NFG*IR+, and 5.04 (4.33–5.74) for IFG (p<0.001)].
Conclusion: Insulin resistance was independently associated with impaired FMD. The impairment of FMD was also observed in subjects with insulin resistance even in the presence of normal fasting glucose.
This research has received full or partial funding support from the American Heart Association, AHA Founders Affiliate (Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, Vermont).