Smoking, Secondhand Smoke, and Cardiovascular Disease

Abstract

Smoking is the leading cause of preventable cardiovascular disease (CVD). Epidemiologic and biologic evidence consistently demonstrates that smokers have an increased risk of CVD compared to nonsmokers. Both cardiac and extracardiac CVDs are more prevalent among smokers. Secondhand smoke is an important cause of CVD in nonsmokers. Secondhand smoke increases the risk of CVD by at least 30%, and given that a large part of the population is still breathing secondhand smoke, it is vital to counsel patients to avoid secondhand smoke exposure. The effects of tobacco smoke on the cardiovascular system accrue over a short period of time and are synergistic with other established cardiovascular risk factors. Tobacco smoke affects the cardiovascular system within minutes of exposure. Smokers and nonsmokers should be aware of this fact. Smokers should be encouraged to quit, and nonsmokers should fight for smoke-free environments. Every smoker should be encouraged to quit and every patient should be informed about the harmful effects of secondhand smoke (SHS) exposure. Smoking cessation has been proven to decrease mortality, regardless of age at quitting or disease stage. Several pharmacologic agents are now available to help patients quit. Pharmacotherapy is more likely to be effective if complemented with behavioral counseling. Secondhand smoke counseling will increase the likelihood of quitting for a smoker and encourage nonsmokers to advocate for smoke-free environments. At the very least, physicians should refer smokers to a quit line. Options should be discussed with the patient and behavioral treatment should be encouraged as it increases the likelihood of success. Smoking cessation is also effective in reducing CVD mortality. The excess risk of myocardial infarction (MI) is reduced by 50% within 1 year of quitting. Physicians should become tobacco control activists. A comprehensive tobacco control program, that includes taxation, smoke-free environments, and exposing the tobacco industry, has been shown to be effective in decreasing smoking prevalence and cardiovascular disease mortality. Physicians should become actively involved in the fight against tobacco. The mechanisms by which tobacco smoke leads to CVD include platelet activation, endothelial dysfunction, inflammation, altered lipid levels and metabolism, and hemodynamic effects. These effects interact with each other and are synergistic with other established CVD risk factors (e.g., obesity, diabetes). Some of these effects occur soon after exposure has happened; as little as half an hour of SHS exposure leads to platelet and endothelial dysfunction. A comprehensive tobacco control program reduces CVD mortality. Smoke-free environments are among the most effective measures to reduce CVD mortality. In addition to protecting nonsmokers from secondhand smoke, these environments make it easier for smokers to cut down or quit. Physicians should become active tobacco control advocates.