Prevention Of Cardiovascular Disease

Cardiovascular diseases, including coronary heart disease (CHD) and stroke, represent two of the most important causes of morbidity and mortality in developed countries. Several risk factors increase the risk for coronary disease and stroke. They can be divided into those that are modifiable (eg, lipid disorders, hypertension, cigarette smoking) and those that are not (eg, gender, age, family history of early coronary disease). This section considers the role of screening for and treating modifiable risk factors.

Impressive declines in age-specific mortality rates from heart disease and stroke have been achieved in all age groups in North America during the past 2 decades. The chief reasons for this favorable trend appear to be modification of risk factors, especially cigarette smoking and hypercholesterolemia, plus more aggressive detection and treatment of hypertension and better care for patients with heart disease. In addition, it now appears that screening for abdominal aortic aneurysm in men aged 65–75 years is associated with a significant reduction in mortality (odds ratio, 0.57 [95% CI, 0.45 to 0.74]); this benefit has not been found for women.

Cigarette Smoking

Cigarette smoking remains the most important cause of preventable morbidity and early mortality. In 2000, there were an estimated 4.8 million premature deaths in the world attributable to smoking, 2.4 million in developing countries and 2 million in industrialized countries. More than three-quarters (3.8 million) of these deaths were in men. The leading causes of death from smoking were cardiovascular diseases (1.7million deaths), chronic obstructive pulmonary disease (COPD) (1 million deaths), and lung cancer (0.9 million deaths). Nicotine is highly addictive, raises brain levels of dopamine, and produces withdrawal symptoms on discontinuation. Cigarettes are responsible for one in every five deaths in the United States, yet smoking prevalence rates have been increasing among high school and college students. Cigar smoking has also increased; there is also continued use of smokeless tobacco (chewing tobacco and snuff), particularly among young people. Tobacco dependence may have a genetic component.

Smokers have twice the risk of fatal heart disease, 10 times the risk of lung cancer, and several times the risk of cancers of the mouth, throat, esophagus bladder, and cervix; a twofold to threefold higher incidence of stroke and peptic ulcers (which heal less well than in nonsmokers); a twofold to fourfold greater risk of fractures of the hip, wrist, and vertebrae; four times the risk of invasive pneumococcal disease; and a twofold increase in cataracts. In the United States, over 90% of cases of COPD occur among current or former smokers. Both active smoking and passive smoking are associated with deterioration of the elastic properties of the aorta (increasing the risk of aortic aneurysm) and with progression of carotid artery atherosclerosis. Smoking has also been associated with increased risks of leukemia, of colon and prostate cancers, of breast cancer among postmenopausal women who are slow acetylators of N-acetyltransferase-2 enzymes,osteoporosis, and Alzheimer’s disease. In cancers of the head and neck, lung, esophagus, and bladder, smoking is linked to mutations of the P53 gene, the most common genetic change in human cancer. Patients with head and neck cancer who continue to smoke during radiation therapy have lower rates of response than those who do not smoke. Olfaction and taste are impaired in smokers, and facial wrinkles are increased. Heavy smokers have a 2.5 greater risk of age-related macular degeneration. Smokers die 5–8 years earlier than never-smokers.

The children of smokers have lower birth weights, are more likely to be mentally retarded, have more frequent respiratory infections and less efficient pulmonary function, have a higher incidence of chronic ear infections than children of nonsmokers, and are more likely to become smokers themselves. In addition, exposure to environmental tobacco smoke has been shown to increase the risk of cervical cancer, lung cancer, invasive pneumococcal disease, and heart disease; to promote endothelial damage and platelet aggregation; and to increase urinary excretion of tobacco-specific lung carcinogens. The incidence of breast cancer may be increased as well. Of approximately 450,000 smoking-related deaths in the United States annually, as many as 53,000 are attributable to environmental tobacco smoke. Smoking cessation lessens the risks of death and of myocardial infarction in people with coronary artery disease; reduces the rate of death and acute myocardial infarction in patients who have undergone percutaneous coronary revascularization; lessens the risk of stroke; slows the rate of progression of carotid atherosclerosis; and is associated with improvement of COPD symptoms. On average, women smokers who quit smoking by age 35 add about 3 years to their life expectancy, and men add more than 2 years to theirs. Smoking cessation can increase life expectancy even for those who stop after the age of 65. Fortunately, adult rates in the United States are now at an all-time low—23%—but rates are climbing for young people.

Although tobacco use constitutes the most serious common medical problem, it is undertreated. Over 70% of smokers see a physician each year, but only 20% of them receive any medical quitting advice or assistance. (Persons whose physicians advise them to quit are 1.6 times as likely to attempt quitting.) About 4% of smokers are able to quit each year., pancreas, kidney. A system should be implemented to identify smokers, and advice to quit should be tailored to the patient’s level of readiness to change. Pharmacotherapy to reduce cigarette consumption is ineffective in smokers who are unwilling or not ready to quit. Conversely, all patients trying to quit should be offered pharmacotherapy except those with medical contraindications, women who are pregnant or breastfeeding, and adolescents.

Several pharmacologic therapies have been shown to be effective in promoting cessation. Nicotine replacement therapy doubles the chance of successful quitting. The nicotine patch, gum, and lozenges are available over-the-counter, and nicotine nasal spray and inhalers by prescription. When the spray is combined with the patch, cessation rates are substantially higher. The sustained-release antidepressant drug bupropion (150–300 mg/d orally) is an effective smoking cessation agent and is associated with minimal weight gain, although seizures are a contraindication. It acts by boosting brain levels of dopamine and norepinephrine, mimicking the effect of nicotine. Bupropion, either alone or in combination with a nicotine patch, has been shown to produce significantly higher abstinence rates (30–35% at 1 year) than either a patch alone or placebo. Weight gain was less in the combined program.

More recently, varenicline, a partial nicotinic acetylcholine-receptor agonist, has shown promise as an effective agent. Weight gain occurs in most patients (80%) following smoking cessation. For many it averages 2 kg, but for others (10–15%) major weight gain—over 13 kg—may occur. Clinicians should not show disapproval of patients who have not stopped smoking or who are not ready to make a quit attempt. Thoughtful advice that emphasizes the benefits of cessation and recognizes common barriers to success can increase motivation to quit and quit rates. An intercurrent illness such as acute bronchitis or acute myocardial infarction may motivate even the most addicted smoker to quit. Individualized or group counseling is very cost effective, even more so than treating hypertension. Smokking cessation counseling by telephone (“quitlines”) has proved effective. An additional strategy is to recommend that any smoking take place out of doors to limit the effects of passive smoke on housemates and coworkers. This can lead to smoking reduction and quitting. The clinician’s role in smoking cessation is summarized in. Public policies, including higher cigarette taxes and more restrictive public smoking laws, have also been shown to encourage cessation.