Comparison of two measures of atherosclerosis in a prospective epidemiology study

Two different methods of measuring atherosclerosis, the American Heart Association panel method and the International Atherosclerosis Project unaided visual estimation, were used to estimate the extent of atherosclerosis in the coronary arteries and aortas from 225 men who participated in a prospective study of cardiovascular disease. The two methods produced quite different results of frequency distribution of levels of atherosclerosis. The correlations of the two measures of atherosclerosis were also relatively low for both the coronary arteries (0.63) and the aortas (0.74). The correlation of atherosclerosis with major risk factors was generally higher with the unaided visual estimation method than with the panel method, except for cigarette smoking. However, the associations of coronary atherosclerosis with autopsy-documented myocardial infarction and with clinical coronary disease were similar for the two measures. Thus, it is clear that the estimate of extent of atherosclerosis and its associations with major risk factors depends upon the method used to measure atherosclerosis. Epidemiologic studies that use only one method may miss some types of risk factor associations.