Cerebral artery atherosclerosis and diet.

In the early years of epidemiologic investigation of the clinical disease syndromes related to atherosclerosis, the focus was on coronary heart disease as the complication most frequently responsible for precocious disability and mortality. Out of these investigations, serum cholesterol concentration, blood pressure, and cigarette smoking emerged as the strongest and most consistent predictors of coronary heart disease. These predictors comprised a mixture of environmental agents (smoking) and intervening variables that represented genetic-environmental interactions (serum cholesterol and blood pressure) and were found to be associated with the other clinical manifestations of atherosclerosis, namely, stroke and peripheral vascular disease. By conventional gross, microscopic, and chemical analyses, the atherosclerotic arterial lesions underlying stroke and peripheral vascular disease are indistinguishable from those occurring in the coronary arteries. However, cigarette smoking and diabetes were recognized as the dominant predictors for peripheral vascular disease while serum cholesterol concentration was a relatively weak predictor. Indeed, peripheral vascular disease (including aneurysm of the abdominal aorta) almost never occurs in the absence of smoking or diabetes. We suspect, but are less than certain, that smoking and diabetes would not be associated with peripheral vascular disease if the overall average serum cholesterol concentration were low in the population examined. Somehow, elevated serum cholesterol appears to be a necessary, but not sufficient, condition for the development of peripheral vascular disease. A different pattern emerged from the epidemiology of stroke, for which blood pressure was recognized as the dominant predictor; serum cholesterol, a significant but less strong predictor; and cigarette smoking, a weak predictor. Similar associations were found for blood pressure and serum cholesterol with atherosclerosis in the cerebral arteries.