Abstract
Coronary arteries and aortas obtained at autopsy in six populations were examined microscopically. Two variants of atherosclerosis could be separately quantified by objective morphometry. These two variants, fibroplasia and atheronecrosis, were both found to increase with age and to correlate with each other from one autopsy to the next after age adjustment. Despite the correlation of these two variables among individuals, the measures of fibroplasia and atheronecrosis did not correlate with each other across population groupings. A positive correlation of this kind between some populations was canceled by an inverse correlation between other populations. For example, Manila was the population with the greatest intimal fibroplasia in the coronary arteries at each age, and Sao Paulo was among those with the least intimal fibroplasia. Nevertheless, Sao Paulo showed the greatest tendency toward atheronecrosis, while Manila was among the populations with the least tendency toward atheronecrosis. The possibility arises, therefore, that the subjects from Sao Paulo were exposed to a different assortment of etiologic agents than were the subjects from Manila, and that their arteries, therefore, manifested a different kind of atherosclerosis.