Insulin Resistance Correlates with the Arterial Stiffness before Glucose Intolerance

Objective The elevated plasma glucose level and/or insulin resistance in diabetes or impaired glucose tolerance play important roles in the pathogenesis of arterial stiffness. The present study investigated whether insulin resistance correlated with arterial stiffness before the development of glucose intolerance. Methods We conducted a cross-sectional analysis in 872 young to middle-age individuals with normal glucose tolerance (aged 36.2 +/- 8.5 years, BMI 24.6 +/- 3.1 kg/m(2) [mean +/- SD]). The homeostasis model assessment (HOMA) index was used as a quantitative assessment of the fasting insulin resistance (FIR), and the plasma insulin level after glucose loading was adopted as an index of the post-challenge insulin resistance (PIR). The Matsuda index [ISI (composite)] was used as a measurement of the insulin sensitivity. The arterial stiffness assessed by the brachial-ankle pulse wave velocity (baPWV) was adopted to quantify its independent associations with insulin resistance. Results The univariate linear regression analysis indicated that the fasting plasma glucose level (FPG, beta= 68.2; 95% CI 40.9, 95.6; p<0.001), post-challenge plasma glucose level (PPG, beta=25.3; 95% CI 15.6, 35.0; p<0.001), FIR (beta=24.5; 95% CI 14.1, 35.0; p<0.001), PIR (beta=1.30; 95% CI 0.87, 1.73; p<0.001) and ISI (composite) (beta=-3.55; 95% CI -5.02, -2.07; p<0.001) were all significantly correlated with the baPWV. After adjustment for sex, age, BMI, heart rate, smoking, systolic blood pressure, total cholesterol, LDL-cholesterol and family history of diabetes, the multivariate linear regression analysis demonstrated that the PIR (model 1, beta=0.39, p=0.038; model 2, beta=0.39, p=0.035; model 3, beta=0.39, p=0.035) was an independent contributor to the baPWV, while the FIR, FPG, PPG and ISI (composite) failed to show any significant contribution. Conclusion The insulin resistance correlated with the arterial stiffness before glucose intolerance.