Abstract
Introduction:
Many pathological mechanisms associated with smoking have been described, but studies on cigarette smoking in relation to carotid plaque morphology are lacking. Given that certain plaque compositions are more prone to cause cerebrovascular events, we sought to determine the association of carotid plaque density and cigarette smoking in an urban multi-ethnic cohort.
Methods:
This cross-sectional study analyzed 1743 stroke-free participants from the population-based Northern Manhattan Study using an ultrasonographic index of plaque echodensity, the Grey Scale Median (GSM). Echolucent plaque (low GSM) is more soft and fibrous, while echodense (high GSM) is more calcified. For individuals with multiple plaques, the mean GSM weighted by plaque area for each plaque was calculated. Quintiles of GSM were calculated among those with plaque and compared to those with no plaque as the reference. We used multinomial logistic regression models to assess the associations of current cigarette smoking with GSM, adjusting for demographics and vascular risk factors.
Results:
The mean age was 65.5±8.9 years, 60% were women, 18% white, 63% Hispanic, 19% black, 14% current smokers, 38% former smokers, and 48% never smokers. Carotid plaque was present in 58% of subjects. Current smokers were at a two-fold increased risk of being in GSM quintiles 1, 2, 4, and 5 as compared to never smokers (Table).
Conclusions:
A U-shaped relationship between current cigarette smoking and plaque echodensity is observed. Smoking is associated with both echodense calcified plaque as well as with echolucent, soft plaque that are more prone to rupture. Research is needed to determine if these vulnerable plaque phenotypes may mediate an association between cigarette smoking and clinical vascular events.