Abstract 2755: Insulin Resistance and Coronary Artery Calcification measured by Electron Beam Tomography
Background: Elevation in the ratio of triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) has been suggested as a marker of insulin resistance (IR), conferring an increased risk of atherosclerosis in these patients. The association between TG/HDL-C and coronary artery calcification (CAC) measured by computed tomography has yet to be established. The goal of this study was to examine the relationship between IR, as determined by TG/HDL-C ≥ 3.5, and significant CAC (absolute score ≥ 100).
Methods: Fasting lipid levels, homocysteine, C reactive protein and lipoprotein (a) levels of 336 asymptomatic individuals, who also underwent electron beam tomography (EBT), were measured.
Results: The mean age of participants was 55 ±10 years. 71.7% were male. 37.4% had hypertension, 52.5% had hypercholesterolemia, 12.4% had diabetes mellitus (DM) and 52.5% had family history of premature CHD. Individuals with IR had higher significant CAC (≥100) than those without IR (70% vs. 27%, P=0.0001). After adjustment for age, gender, hypertension, hypercholesterolemia and DM, multivariate regression analysis demonstrated that individuals with IR had more significant CAC (odds ratio 2.1, 95% CI=1.1–3.9, p=0.01). Further sub-analysis revealed that individuals with IR had significantly higher lipoprotein (a) (Lp(a)) than those without IR (odds ratio 1.31, 95% CI=1.09-.16, p=0.03). No significant differences in C-reactive protein (CRP) and homocysteine were found between the two groups.
Conclusion: Insulin resistance, as measured by TG/HDL-C ≥ 3.5, was associated with a significantly higher incidence of accelerated atherosclerosis on EBT (absolute CAC score ≥ 100), independent of age, gender and conventional risk factors. IR was also significantly associated with elevated levels of Lp(a). Further studies regarding the clinical significance of insulin resistance and elevated CAC score, as well as its association with Lp(a), may be warranted.