Epidemiology of atherosclerosis: an updated overview

Ongoing epidemiologic research continues to provide new insight into the multifactorial etiology of atherosclerosis and coronary artery disease (CAD). Cigarette smoking remains a primary risk factor; low tar and nicotine cigarettes have apparently not contributed to a reduced incidence of CAD and cardiovascular death. The stepwise risk of increasing levels of diastolic blood pressure to cardiovascular death is well known; however, elevated systolic blood pressure may be a more potent risk factor. The benefits of treating diastolic blood pressure greater than or equal to 115 mm Hg are indisputable; the benefits of treating milder hypertension, i.e., diastolic blood pressure between 90 and 114 mm Hg, probably outweigh the risks, but controversy persists. Low-density lipoprotein cholesterol, which comprises approximately 70% of total cholesterol, is strongly associated with CAD. Studies continue to relate hypercholesterolemia and CAD, showing approximately a 2% reduction in disease for each 1% reduction in total cholesterol. The influences of diabetes mellitus, thrombosis and psychosocial factors in the genesis of CAD are reviewed, as well as the evidence supporting the synergistic hazard presented by risk-factor clusters. High-density lipoprotein cholesterol bears an inverse, protective relation to CAD. Factors affecting high-density lipoprotein levels, e.g., obesity/exercise, cigarette smoking, alcohol consumption and postmenopausal use of estrogen in women, are also reviewed in light of recent findings. Additional investigation is necessary to clarify the benefits and risks associated with the treatment or modification of known risk factors and to identify others.