SMOKING AND CARDIOVASCULAR-DISEASE

Cigarette smoking is the most preventable cause of cardiovascular morbidity and mortality. Smoking has been associated with a two-to fourfold increased risk of coronary heart disease, a >70% excess rate of death from coronary heart disease, and an elevated risk of sudden death. These risks are compounded in the presence of hypertension, hypercholesterolemia, glucose intolerance, and diabetes, all of which exhibit a synergistic effect with smoking. The relationship between smoking and the risk of peripheral vascular disease has also been well documented. Smokers account for approximately 70% of patients with atherosclerosis obliterans and virtually all those with thromboangiitis obliterans. An association between smoking and cerebrovascular disease remains a matter of debate, although a higher risk of stroke and stroke-related mortality has been observed in smokers than in nonsmokers. Smoking has also been implicated in the development of cor pulmonale, but a direct association with congestive heart failure has not been established. Nicotine and carbon monoxide appear to play major roles in the cardiovascular effects of smoking. Both components adversely alter the myocardial oxygen supply/demand ratio and have been shown to produce endothelial injury, leading to the development of atherosclerotic plaque. Adverse effects on the lipid profile have been noted as well, but the relationship between these changes and the risk of cardiovascular disease remains to be confirmed. Notably, smoking cessation results in a dramatic reduction in the risk of mortality from both coronary heart disease and stroke. In light of the fact that the incidence of smoking has declined primarily among educated sectors of the U.S. population, future efforts must focus on providing effective education, including smoking cessation techniques, to the less-educated groups.