Comparison between measures of atherosclerosis and risk of stroke: the Rotterdam Study

Abstract

Background and purpose: Several measures of atherosclerosis predict the risk of stroke. However, a comparison between various measures of atherosclerosis is lacking, and limited information exists on the added value of individual measures of atherosclerosis to cardiovascular risk factors. We compared different measures of atherosclerosis in relation to stroke.

Methods: The study was based on the prospective cohort of the Rotterdam Study and included 6913 participants who did not suffer from previous stroke. At baseline, carotid intima-media thickness and plaques, ankle-arm index, and aortic calcifications were assessed; 3996 participants (53%) had measures of all studied markers of atherosclerosis. After a mean follow-up of 6.1 years, 378 strokes occurred. Data were analyzed with Cox proportional-hazards regression and Akaike information criteria scores.

Results: Carotid intima-media thickness and aortic calcifications were related most strongly to the risk of stroke (relative risk, 2.23 and 1.89; 95% confidence interval, 1.48 to 3.36 and 1.28 to 2.80 for highest versus lowest tertile, respectively). The relations between intima-media thickness, aortic calcifications, and carotid plaques and stroke remained after adjustment for cardiovascular risk factors. Intima-media thickness and aortic calcifications were related to the risk of stroke independently of each other. The relation between ankle-arm index and stroke disappeared after adjustment for cardiovascular risk factors.

Conclusions: Carotid intima-media thickness and aortic calcifications are stronger predictors of incident stroke than carotid plaque or ankle-arm indexes. They have additional value to each other and to classic risk factors and may reflect different processes.