The association between coronary calcification assessed by electron beam computed tomography and measures of extracoronary atherosclerosis

OBJECTIVES: The present study was designed to examine the associations of coronary calcification assessed by electron beam computed tomography (CT) with measures of extracoronary atherosclerosis. BACKGROUND: Although measures of extracoronary atherosclerosis have been used to predict coronary events, it is not yet known to what extent those measures reflect coronary atherosclerosis. METHODS: The Rotterdam Coronary Calcification Study is a population-based study in subjects age 55 years and over. Participants of the study underwent an electron beam CT scan. Coronary calcification was quantified according to the Agatston calcium score. Measures of extracoronary atherosclerosis included common carotid intima media thickness (IMT), carotid plaques, ankle-arm index (AAI) and aortic calcification. We used the first 2,013 participants for the present analyses. Age-adjusted geometric mean calcium scores were computed for categories of extracoronary measures using analyses of variance. RESULTS: Graded associations with coronary calcification were found for the carotid and aortic measures. Associations were strongest for carotid plaques and aortic calcification; coronary calcification increased from the lowest category (no plaques) to the highest category 9-fold and 11-fold in men and 10-fold and 20-fold in women, respectively. A nonlinear association was found for AAI with an increase in coronary calcification only at lower levels of AAI. CONCLUSIONS: In this population-based study, graded associations were found between coronary calcification and common carotid IMT, carotid plaques and aortic calcification. A nonlinear association was found between coronary calcification and the AAI.