The latest statistics on the prevalence of cigarette smoking come from the 2003 National Health Interview Survey (NHIS) that was administered to a nationally representative sample of more than 30,000 adults. The NHIS defines current smokers as persons who reported smoking every day or some days. Former smokers were defined as persons who no longer smoked. The NHIS results indicated that, in 2003, approximately 21.6% of U.S. adults were current smokers. This number suggests a decline in prevalence from 22.5% in 2002. In fact, over the past decade, smoking rates have steadily declined among most age groups in the U.S. Smoking cessation rates suggest a similar trend. The NHIS findings show that among the estimated 43.4% (91.5 million) of persons who had ever smoked, 50.3% (45.9 million) were classified as former smokers in 2003. While progress has been made in decreasing smoking rates overall, prevalence remains high among certain subpopulations of smokers. More men (24.1%) than women (19.2%) smoke. Smoking is highest among American Indians and Alaska Natives (39.7%) compared to Asians (11.7%) and Hispanics (16.4%). Smoking rates tend to vary by education level, with prevalence highest among adults who had earned a General Educational Development diploma (44.4%) and lowest among those with graduate degrees (7.5%). Across age groups, prevalence is highest in persons aged 25-44 years (25.6%) and lowest among persons aged greater than 65 years (9.1%).
Smoking is the leading cause of premature death in the United States, resulting in more than 440,000 deaths each year (from Centers for Disease Control, CDC, 2002). Because of smoking, adult female and male smokers lose an average of 14.5 and 13.2 years of life, respectively. Cigarette smoking significantly increases the risk of lung cancer, ischemic heart disease, chronic airway obstruction, and perinatal complications (CDC, 2002). The health benefits of quitting smoking are substantial, including a decreased risk of lung cancer, other cancers, cardiovascular disease, chronic lung disease, and infertility. Exposure to environmental tobacco smoke (ETS), a known human carcinogen, also increases the risk of cancer and is associated with the deaths of almost 40,000 nonsmokers each year (from National Cancer Institute, 1999). The economic costs of smoking are tremendous, with each pack of cigarettes sold in the United States resulting in costs of $7.18 in medical care and lost productivity (CDC, 2002). It is estimated that $75.5 million is spent each year on smoking-related medical care (CDC, 2002).
Although nicotine is the reason that people have used tobacco for centuries, it is the combustion products of smoking that cause nearly all of the disease. At least 4,700 different chemicals of tobacco smoke have been identified, with many known to be carcinogenic (cancer-causing in humans). Those chemicals observed at higher concentrations (> 1 microgram) have been categorized into four groups: carbon monoxide; other vapor phase components (e.g., acetaldehyde, formaldehyde, nitrogen oxides); particulate matter or “tar”; and nicotine. These four components of cigarette smoke are delivered to the active smoker as a complex aerosol composed of semi-liquid particles of combustion gases. A substantial amount of literature supports the association between these smoke components and risk for development or exacerbation of cardiovascular and pulmonary disease.
Tobacco use usually begins during adolescence; however initiation also can occur during young adulthood. Not everyone who experiments with cigarette smoking goes onto become nicotine dependent. For those who do continue smoking (approximately 40%), the development of dependence seems to involve a progression through a series of stages. Initial use is largely driven by psychosocial motives or nonpharmacological factors, such as social pressure, appearance, self-esteem; whereas later use is motivated more by pharmacological factors including positive nicotine effects and withdrawal relief. Identifying which adolescents in the early stages will proceed to become established, dependent smokers has been the focus of considerable research. Beliefs and attitudes related to smoking appear to be important predictors, along with exposure to other smokers and perceived school performance. There may be gender differences in determinants of smoking and nicotine dependence. Some research shows that for girls, a strong need for social interaction influences smoking development, whereas for boys, higher levels of depression symptoms are more influential. For girls, smoking onset and continuation may be influenced by concern for weight and body shape. Other models suggest that initial exposure predicts continued smoking. According to one model, more sensitive individuals, that is, those who encounter aversive effects on initial use, are less likely to engage in further experimentation; whereas people with less sensitivity to nicotine experience fewer unpleasant effects and, as a consequence, are more likely to continue. An alternative model proposes that dependent smokers are those who are more sensitive to nicotine. For them, initial exposure to smoking produces aversive and rewarding effects, with continued exposure associated with a decrease in sensitivity as tolerance develops. Finally, genetic influences on smoking and dependence must be considered. Twin studies have shown that genetic factors may make a stronger contribution to nicotine dependence (61 percent) than environmental factors (39 percent). Recent research suggests that certain alleles in a gene are responsible for regulating nicotine metabolism and may in fact protect some smokers from becoming dependent on nicotine. Thus, it appears that development of nicotine dependence results from a complex interplay of multiple factors.
Smoking cessation at any age is beneficial in terms of health consequences and life extensions. In general, the health benefits of quitting smoking are proportionate to the number of years since quitting. According to some estimates, quitting smoking before middle age may prevent up to 90% of the excess mortality attributable to cigarette smoking. Taylor and coauthors examined data from the Cancer Prevention Study II to estimate life expectancy associated with stopping smoking at various ages. In their 2002 article, published in the American Journal of Public Health (volume 92), study results showed that people live substantially longer when they stop smoking, regardless of the age at which they quit. Quitting at a younger age is better, however even smokers who quit at age 65 gained several years of life expectancy relative to those who continue to smoke. The take-home message from research literature on smoking and health is that quitting smoking decreases the risk of lung cancer, other cancers, heart attack, stroke, and chronic lung disease. Statistics vary across studies, but according to the US Surgeon General’s Report, after 1 year of quitting the excess of coronary heart disease is half that of a smoker’s. After 5 years of quitting, risk for stroke is reduced to that of a nonsmoker. After 10 years of quitting, lung cancer death rate is about half that of a continuing smoker's. Finally, after 15 years after quitting the risk of coronary heart disease is that of a non-smoker's.
The Environmental Protection Agency (EPA) classifies secondhand smoke as a known cause of cancer in humans. Hundreds of chemicals in tobacco smoke are toxic or carcinogenic. It is estimated that approximately 3,400 lung cancer deaths and 46,000 heart disease deaths in US adult nonsmokers are attributable to secondhand smoke. Young children are especially vulnerable to secondhand smoke, which places them at increased risk for lower respiratory tract infections, ear infections, and asthma. The significant personal and public health consequences of secondhand smoke have resulted in recent legislation prohibiting smoking in almost all public places and workplaces across many states. Smoke-free workplaces have been shown to have increased productivity and decreased absenteeism among employees. According to a recent Surgeon General’s Report, there is no risk-free level of exposure to secondhand smoke. Not smoking in indoor space is the only way to fully protect non-smokers from exposure to secondhand smoke.
Although fewer women smoke than men, the gender gap in smoking prevalence has steadily narrowed over the past decades. Reflected by these statistics is the fact that lung cancer, not breast cancer, is the leading cause of cancer deaths among women in the U.S. In recent years women have been targeted by tobacco marketing strategies, portraying smoking as associated with being slim, independent, attractive and athletic. Mothers who smoke during pregnancy face increased risk of serious health problems, including pregnancy complications, premature birth, low-birth-weight infants, stillbirth, and infant death. When it comes to quitting smoking, women face unique barriers. For example, women tend to have lower confidence in their ability to quit, a greater likelihood of depression, and greater weight control concerns. Studies have shown that, not only are women more concerned about weight gain following quitting, they actually do gain slightly more post-cessation weight than do men. Treatments that target these concerns through diet and exercise interventions, have shown good results.
The familiar saying, “it’s never too late to quit smoking” is not a myth. Indeed, the likelihood of successful cessation increases with each quit attempt. Most smokers make numerous quit attempts before finally achieving longterm success. Those who quit smoking in late life have higher levels of physical function and better quality of life than continuing smokers. While the health benefits of smoking cessation in older adults varies, depending on an individuals smoking history and disease state upon cessation, at the population level, the prospects are excellent that smoking cessation after age 65 will extend both the number of years of life and the quality of life.
Initial tobacco use typically occurs before high school graduation. According to survey results by the Centers for Disease Control (CDC), about 28% of high school students, nationwide, report using some type of tobacco during the past month. On average, about 23% of high school students smoke cigarettes, with girls as likely to smoke as boys. In general, kids who avoid smoking during their teenage years are unlikely to become regular smokers. Children and teens who smoke are at increased risk for health problems, including chronic cough, shortness of breath, respiratory illnesses, reduced physical fitness, poor lung growth and function, and worse overall health (American Cancer Society). Kids who smoke regularly can be addicted to nicotine and experience significant withdrawal symptoms upon cessation. Many teens say that they would like to quit smoking and experience the same challenges as adults when they attempt to quit.