Determinants of carotid plaque occurrence. A long-term prospective population study: the San Daniele Project.

BACKGROUND: Increased carotid intima media thickness (CIMT) is frequently associated with established modifiable and non-modifiable cardiovascular risk factors, and is thought to be an independent predictor of ischemic cerebrovascular and cardiac events. The presence of carotid plaque is considered an established feature of atherosclerosis. There exist few longitudinal data on the predictive role of CIMT in the occurrence of carotid plaque.

METHODS: We restudied the survivors of a cohort of the San Daniele Project, a large randomized general population study, investigated in 1990 regarding the prevalence and determinants of carotid atherosclerosis. Using ultrasonography, we determined in 1,193 subjects (548 men and 645 women), the common carotid IMT and the presence of non-stenotic and stenotic plaque.

RESULTS: In 795 subjects without plaques or previous ischemic events at baseline, we found in multivariate analysis that CIMT > or =1 mm, age, hypertension and history of smoking are significant predictive elements of the occurrence of a new carotid plaque. The incremental probability of plaque occurrence is greater in midlife. CIMT and age are the most predictive risk factors with ORs of 3.66 (95% CI 1.4-9.4) and 3.02 (95% CI 2.4-3.7), respectively. The ORs for hypertension and smoking account for 1.5 (95% CI 1.1-3.4) and 1.7 (95% CI 1.1-2.8), respectively.

CONCLUSIONS: Age, hypertension, history of smoking and B-mode detection of CIMT increases in subjects without carotid atherosclerosis and free of previous vascular events predict the occurrence of carotid atherosclerotic plaque.