Background and purpose: Ultrasound-assessed plaque morphology is an independent predictor of ischemic stroke. The purpose of this population-based cross-sectional nested case-control study was to examine the risk factors associated with carotid plaque morphology.
Methods: Ultrasonography of the right carotid artery was conducted on 6727 participants in a population health survey (response rate 79%). Plaque echogenicity, defined as reflectance of the emitted ultrasound signal, was scored as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Information on cardiovascular risk factors in all 216 participants who had carotid stenosis and in 223 control subjects matched by age and sex who did not have carotid stenosis was obtained from measurements of blood pressure, weight, height, and nonfasting blood samples and from a self-administered questionnaire.
Results: In both univariate and multivariate analyses, low levels of HDL cholesterol and increasing degree of stenosis were independently associated with an increased risk of having an echolucent plaque. For 1-SD increase in HDL cholesterol, the adjusted odds of being in a lower plaque echogenicity category decreased by approximately 30% (OR 0.69, 95% CI 0.52 to 0.93).
Conclusions: These findings indicate that low levels of HDL cholesterol are associated with an increased risk of having echolucent, rupture-prone atherosclerotic plaques.