Abstract

Of the risk factors related to coronary heart disease, three clearly stand out: elevated blood pressure, cigarette smoking, and elevated levels of serum cholesterol. Recently, considerable evidence has accumulated indicating that, in addition to concentration of total blood cholesterol, the manner in which cholesterol is distributed or transported in the blood may be associated with the risk of developing coronary heart disease. Specifically, the level of one particular lipoprotein called high density lipoprotein (HDL) appears to be an important predictor of the possibility of developing heart disease. The higher the proportion of HDL the lower the risk of developing heart disease. In general, the blood concentrations of HDL cholesterol are high in children, decrease with age, and are the lowest in sufferers of coronary heart disease. This observation is true in both blacks and whites. The relationship between physical activity and blood cholesterol has not been definitely established. Preliminary reports indicate that exercise does, in fact, raise blood levels of HDL cholesterol and may thus provide some protective effect to coronary heart disease. Data are only now emerging as to the specific effects of diet, stress, or diabetes on the proportion changes of serum HDL cholesterol and their possible interaction in CHD. New and exciting relationships appear to be close at hand.