Smoking and Other Tobacco Use

The percentage of people in the United States who smoke cigarettes has declined since 1964, when the Surgeon General first publicized the link between smoking and ill health. Nevertheless, 11.5% of adults (28.3 million) in the United States still smoke cigarettes (1).

Smoking is more prevalent among the following groups:

• Men

• Young adults

• People who identify as lesbian, gay, bisexual, or transgender

• People with disabilities

• People with less than a high school education

• People living at or below the poverty income level

• People with psychiatric disorders (including alcohol and substance use)

• American Indian and Alaskan Native people

Smoking is less common among Hispanics and least common among Asian American women.

Nearly all people who smoke start before the age of 18, making tobacco use a pediatric disorder (2). Each day, approximately 2300 youth under age 18 smoke their first cigarette, and nearly 200 youth start smoking daily. Major risk factors for childhood initiation of smoking include smoking among family members and peers as well as exposure to tobacco advertising and marketing in print, online, and at the point of sale in stores, along with tobacco use scenes in movies and video games.

Cigar and pipe smoking are less common in the United States. In 2021, an estimated 8.6 million people aged 18 or older (3.5%) smoked cigars and 2.3 million (0.9%) smoked a pipe, water pipe, or hookah (1). These percentages have remained relatively stable over the past 15 years. Health harms of pipe and cigar smoking include cardiovascular disease; COPD; cancers of the oral cavity, lung, larynx, esophagus, colon, and pancreas; and periodontal disease and tooth loss.

E-cigarettes or vape pens are devices consisting of a battery and a cartridge containing an atomizer to heat a solution with propylene glycol, glycerol, and usually but not always nicotine. E-cigarettes mimic the hand-to-mouth action of smoking, and many e-cigarettes deliver high levels of nicotine deep into the lungs, increasing the risk of addiction. With e-cigarettes, there are fewer defined cues that signal the amount consumed, as is experienced with an extinguished cigarette butt. Many e-cigarette devices deliver 5000 to 6000 puffs, which can equate to 500 to 600 cigarettes or 25 to 30 packs of cigarettes.

While there is no combustion involved in using e-cigarettes, the aerosol emitted from the device is more than water vapor. In addition to often containing nicotine, e-cigarette aerosol has ultrafine particles, which can be inhaled deeply into the lungs; flavoring such as diacetyl, a chemical linked to serious lung disease; volatile organic compounds; cancer-causing chemicals; and heavy metals (eg, nickel, tin, and lead), though all at lower levels than in combusted tobacco smoke. While the long-term effects of inhaling e-cigarette aerosol are not clearly known, it is reasonable to speculate that they are likely to be less detrimental than the well-known adverse effects of smoking combustible cigarettes. For people who use e-cigarettes and continue to smoke, a common practice of dual users, the health benefits of e-cigarette use are unproven.

The effects of maternal e-cigarette use on fetal development are unknown, as are the long-term effects of e-cigarette use on the developing adolescent brain. E-cigarette use among youth exceeds combustible tobacco use (2). The long-term risks of e-cigarette smoking, a relatively new phenomenon, are unknown. (See also information about e-cigarettes from the The National Academies of Sciences, Engineering, and Medicine [Health and Medicine Division]: Public health consequences of e-cigarettes.)

E-cigarette and Vaping product-use Associated Lung Injury (EVALI) is a term used by the Centers for Disease Control and Prevention (CDC) to describe a multi-state outbreak of severe lung illness first identified in August 2019 and associated with using e-cigarette and vaping products. The clinical presentation is a diagnosis of exclusion that includes respiratory symptoms (eg, cough, chest pain, shortness of breath), gastrointestinal symptoms (eg, abdominal pain, nausea, vomiting, diarrhea), nonspecific constitutional symptoms (eg, fever, chills, weight loss), reduced blood oxygen levels, elevated white blood cell counts, and injuries resembling those caused by exposures to toxic chemical fumes, poisonous gases, and toxic agents. According to the CDC, as of February 2020, there were over 2800 hospitalizations and 68 deaths nationally due to EVALI. The CDC’s guidelines point largely to vaping of tetrahydrocannabinol (THC) liquid as the cause, and in particular THC liquids cut with vitamin E acetate. The CDC stopped monitoring incidence of EVALI in February 2020 because of the decline in cases and deaths, as well as the identification of vitamin E acetate, which is the most recognized agent associated with EVALI (3). The CDC encourages clinicians to continue to report possible EVALI cases to their local or state health department for further investigation. If EVALI is suspected, the clinician should obtain a detailed history of substances used, sources of products, duration and frequency of use, and devices used and how those devices were used.

Smokeless tobacco (chewing tobacco and snuff) is used by approximately 2.1% of people ≥ 18 years of age (1) and approximately 1.6% of high school students (2). Toxicity of smokeless tobacco varies by brand. Harms include cardiovascular disease, oral disorders (eg, cancers, gum recession, gingivitis, periodontitis and its consequences), and teratogenicity.

Inadvertent oral exposure to tobacco is uncommon but may cause serious toxicity. Young children occasionally ingest cigarettes from unguarded packs, cigarette butts from ashtrays, e-cigarette liquid, or nicotine gum. In 2022, 6745 cases of potentially toxic exposure to e-cigarettes and liquid nicotine products were reported to the American Association of Poison Control Centers (AAPCC) (see AAPCC: E-cigarettes and Nicotine).

Cutaneous exposure to tobacco can be toxic. Tobacco harvesters and processors who handle raw tobacco (especially if wet) without protection may absorb nicotine through the skin and develop symptoms of nicotine toxicity, a syndrome termed green tobacco sickness.

Passive exposure to tobacco smoke (secondhand smoke) occurs when people inhale smoke from a burning cigarette or the smoke exhaled by a person smoking nearby. The amount inhaled (and thus its effects) varies with the proximity and duration of exposure as well as the environment (eg, closed space) and ventilation. The CDC estimates that more than 41,000 deaths each year are due to secondhand smoke exposure (4). (See also CDC: Secondhand Smoke.)

1. 1. Cornelius ME, Loretan CG, Jamal A, et al: Tobacco Product Use Among Adults - United States, 2021. MMWR Morb Mortal Wkly Rep 72(18):475-483, 2023. Published 2023 May 5. doi:10.15585/mmwr.mm7218a1

2. 2. Park-Lee E, Ren C, Cooper M, et al: Tobacco Product Use Among Middle and High School Students - United States, 2022. MMWR Morb Mortal Wkly Rep 71(45):1429-1435, 2022. Published 2022 Nov 11. doi:10.15585/mmwr.mm7145a1

3. 3. Rebuli ME, Rose JJ, Noël A, et al: The E-cigarette or Vaping Product Use-Associated Lung Injury Epidemic: Pathogenesis, Management, and Future Directions: An Official American Thoracic Society Workshop Report. Ann Am Thorac Soc 20(1):1-17, 2023. doi:10.1513/AnnalsATS.202209-796ST

4. 4. Homa DM, Neff LJ, King BA, et al: Vital signs: disparities in nonsmokers' exposure to secondhand smoke--United States, 1999-2012. MMWR Morb Mortal Wkly Rep 64(4):103-108, 2015

Smoking harms nearly every organ in the body. Smoking is the leading cause of preventable mortality in the United States and globally. In the United States, smoking accounts for approximately 500,000 deaths each year. People who smoke are more likely to die prematurely of a disease directly caused by smoking, losing as much as 10 years of life on average. (See also Health Consequences of Smoking, Surgeon General fact sheet.)

The major chronic effects are an increased likelihood of the following:

• Coronary artery disease

• Lung cancer

• COPD (chronic obstructive pulmonary disease)

Coronary artery disease is a major cause of tobacco-related deaths. Risk of myocardial infarction is doubled if smoking 1 pack a day, and risk of cardiovascular mortality is increased by > 50% over a 35-year period. Mechanisms include endothelial cell damage, transient increases in blood pressure and heart rate, induction of a prothrombotic state, and adverse effects on serum lipids. Smoking causes approximately 32% of coronary heart disease deaths (1).

Lung cancer is another major source of tobacco-related deaths. Smoking tobacco is the most common cause of lung cancer in North America and Europe, and accounts for more than 87% of lung cancer deaths (1). Inhaled carcinogens are directly exposed to lung tissue.

COPD also accounts for a significant portion of tobacco-related deaths. Tobacco accounts for 79% of all cases of COPD (1). Smoking impairs local respiratory tract defense mechanisms and, particularly in genetically susceptible people, tends to accelerate decline in pulmonary functions. Coughing and dyspnea on exertion are common.

Less common yet serious smoking-related disorders include age-related macular degeneration, noncardiac vascular diseases (eg, stroke, aortic aneurysm), other cancers (eg, bladder, cervical, colorectal, esophageal, kidney, laryngeal, liver, oropharyngeal, pancreatic, stomach, throat, acute myeloid leukemia), diabetes, pneumonia, rheumatoid arthritis, and tuberculosis.

In addition, smoking is a risk factor for other conditions that convey significant morbidity and disability, such as frequent upper respiratory infections, asthma, cataracts, infertility, erectile dysfunction, premature menopause, peptic ulcer disease, osteoporosis, hip fractures, and periodontitis.

Secondhand smoke is tobacco smoke that is exhaled by a person smoking or given off from the end of a lit cigarette. Secondhand smoke is linked to the same neoplastic, respiratory, and cardiovascular diseases that threaten people who smoke. The risk of illness is related to dose. For example, between spouses, average risk is increased by approximately 20% for lung cancer and by approximately 20 to 30% for coronary artery disease. (See also CDC: Secondhand Smoke.)

Children exposed to cigarette smoke lose more school days because of illness than nonexposed children. Treating children for smoking-related illnesses has been estimated to cost $4.6 billion/year (2).

Overall, secondhand smoke is estimated to cause more than 41,000 deaths each year in the United States (between 2% and 3% of all deaths), with lost productivity costs due to premature deaths from secondhand smoke exposure estimated to be $5.6 billion per year (in 2006) (1). These findings led states and municipalities across the United States to ban smoking within workplaces in an effort to protect the health of workers and others from the substantive risks of environmental tobacco smoke. In 2000, no state or the District of Columbia had a comprehensive indoor smoke-free ordinance in effect. This increased to 26 by the end of 2010, and one additional state was added by the end of 2015. Subsequently, 28 states, Washington DC, Puerto Rico, and the US Virgin Islands have comprehensive smoke-free air laws covering workplaces, restaurants, and bars. In some states without statewide comprehensive smoke-free laws, substantial progress has been made at the local level in adopting comprehensive smoke-free laws. However, 7 states without statewide comprehensive smoke-free laws (Florida, New Hampshire, North Carolina, Oklahoma, Pennsylvania, Tennessee, and Virginia) have preemption statutes that prohibit adoption of local smoke-free air laws. (See also American Lung Association: Smokefree Air Laws)

Smoking during pregnancy increases the risk of spontaneous abortion, ectopic pregnancy, preterm birth, and congenital defects. Infants born of mothers who smoke tend to have a lower birth weight and are at increased risk of

• Sudden infant death syndrome (SIDS)

• Asthma and related respiratory illnesses

• Otitis media

• Orofacial clefts

Indirect effects of smoking can be serious.

Smoking-related fires occur in approximately 7800 residential buildings in the United States each year, according to the Federal Emergency Management Agency (FEMA). These fires cause approximately 275 deaths, 750 injuries, and $361 million in property loss annually. (See FEMA: Residential Building Smoking Fire Trends [2012-2021].) Such fires are the leading cause of deaths resulting from unintentional fires in the United States.

Drug interactions with smoking are common. The effects are largely due to induction of metabolic enzymes in the liver by tar byproducts of smoking. Nicotine does not similarly induce metabolic enzymes, and thus drug-induction effects do not occur with nicotine replacement therapy or e-cigarettes. Levels and sometimes clinical effects of the following medications and substances are decreased by chronic smoking, primarily by induction of CYP2A6 enzymes:

• Estrogens (oral)

• Pentazocine

Two exceptions are benzodiazepines, for which sedation effects are decreased likely due to the stimulating effects of nicotine, and beta-blockers, with reduced blood pressure and heart rate control possibly caused by nicotine-mediated sympathetic activation.

1. 1. National Center for Chronic Disease Prevention and Health Promotion (US) Office on Smoking and Health. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta (GA): Centers for Disease Control and Prevention (US); 2014.

2. 2. Yao T, Sung HY, Wang Y, Lightwood J, Max W: Healthcare costs attributable to secondhand smoke exposure at home for U.S. adults. Prev Med 108:41-46, 2018. doi:10.1016/j.ypmed.2017.12.028

Nicotine slightly increases heart rate, blood pressure, and respiratory rate. People who smoke may feel increased energy and arousal, increased ability to concentrate, decreased tension and anxiety, and a sense of pleasure and reward. Nausea is common on a person's first exposure to nicotine. Nicotine reduces appetite and can be a behavioral substitute for eating. Nicotine's effects are transient given its short half-life. If not repeatedly dosed, the individual experiences the effects of nicotine withdrawal including lethargy, difficulty concentrating, restlessness, anxiety, tension, depressed mood, irritability, and hunger.

With combustible tobacco, exercise tolerance tends to decrease because of respiratory tract irritation. Low-grade carbon monoxide toxicity can also limit exercise tolerance, but this is probably only a factor in elite athletes.

Acute nicotine poisoning is usually caused by oral (eg, children eating a cigarette or nicotine gum or ingesting e-liquid) or dermal (eg, handling raw tobacco products) exposure, rather than smoking.

Mild nicotine toxicity, as is common with green tobacco sickness and minor ingestions by children (eg, < 1 cigarette or 3 butts), typically manifests with nausea, vomiting, headache, and weakness. Symptoms spontaneously resolve, usually in 1 to 2 hours after ingestion if poisoning is mild; however, symptoms can persist for 24 hours if poisoning is severe.

Severe nicotine poisoning causes a cholinergic toxidrome with nausea, vomiting, salivation, lacrimation, diarrhea, urination, fasciculations, and muscle weakness. Patients usually have crampy abdominal pain and, if poisoning is very severe, arrhythmias, hypotension, seizures, and coma. The fatal dose of nicotine is approximately 60 mg in nonsmoking adults, 120 mg in adults who smoke, and as little as 10 mg in young children. Each cigarette contains approximately 8 mg of nicotine (only about 1 mg is absorbed by smoking). However, the amount ingested by children is usually difficult to ascertain by history because ingestion is rarely observed; any ingestion should be considered potentially dangerous.

Findings due to smoking itself include yellow stains of teeth and fingers, and in comparison to age-matched controls, weight is slightly lower (≤ 5 kg difference), skin is drier and more wrinkled, and hair is thinner.

Other symptoms are those of smoking-related lung and cardiovascular disease. Chronic cough and dyspnea on exertion are common. Circulatory and respiratory impairments decrease exercise tolerance, often resulting in a more sedentary lifestyle and thus further lowering of exercise tolerance.

Smoking cessation often causes intense , primarily a craving for cigarettes but also other symptoms (eg, anxiety, difficulty concentrating, sleep disruption, depression) and eventual weight gain.

1. 1. National Center for Chronic Disease Prevention and Health Promotion (US) Office on Smoking and Health. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta (GA): Centers for Disease Control and Prevention (US); 2014.

2. 2. National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Eaton DL, Kwan LY, Stratton K, et al: Public Health Consequences of E-Cigarettes. Washington (DC): National Academies Press (US); January 23, 2018.