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The compulsive use of nicotine products coupled with a lack of control over using, withdrawal symptoms, and/or continued use despite knowledge of or experiencing adverse consequences.
Approximately 40 million people in the United States ≥18 years of age are current tobacco users. In the past year, 58.7 million smoked cigarettes, 13.3 million smoked cigars, 2.1 million smoked pipes, and 8.6 million used smokeless tobacco. An estimated 3 million middle and high school students are current smokers. About 80% of these individuals will continue smoking into adulthood. E-cigarette use among youth has been associated with nicotine addiction in adulthood.
Cost and Impact
Nearly 500,000 Americans die prematurely each year from smoking. The estimated economic costs attributable to smoking and secondhand exposure approach $300 billion annually, with direct medical costs of at least $130 billion.
Etiology and Pathophysiology
- Similar to other addictive drugs, nicotine affects neural pathways that control reward and pleasure.
- Nicotine exerts its biologic effects through nicotinic acetylcholine receptors (nAChRs), which modulate neurotransmission with acetylcholine and other chemical messengers including glutamate, GABA, dopamine, serotonin, acetylcholine, and norepinephrine. In this way it induces euphoria, assists in information processing, reduces anxiety, and mitigates fatigue.
- Up-regulation of these receptors occurs over time leading to tolerance and dependence.
- Polymorphisms in neuronal nAChR genes are associated with increased susceptibility to dependence.
- Nicotine is metabolized by cytochrome P450 2A6 (CYP2A6). Individuals who are fast metabolizers tend to smoke more cigarettes, are more likely to suffer intense withdrawal symptoms, and have a lower probability of quitting than slow metabolizers.
- Nicotine withdrawal involves the release of corticotropin-releasing factor in the amygdala, which induces the perception of anxiety and stress.
- Smoking is a risk factor associated with placenta previa, abruptio placentae, decreased maternal thyroid function, preterm premature rupture of membranes and ectopic pregnancy.
- Carbon monoxide and nicotine interfere with fetal oxygen supply, resulting in decreased birth weights and intrauterine growth restriction.
- Maternal smoking adversely affects fetal lung development, with lifelong decreases in pulmonary function and increased risk of asthma.
- Maternal smoking is associated with increased risk for sudden infant death syndrome, learning and behavioral problems, and obesity.
- Mental illness (depression, posttraumatic stress disorder, bipolar disorder, and schizophrenia)
- Low socioeconomic status
- Low educational status
- Early first-hand nicotine experience
- Concurrent substance abuse
- Home and peer influence
- The U.S. Preventive Services Task Force (USPSTF) strongly recommends (1)[A]:
- Screening all adults for tobacco use and provide cessation interventions for those who screen positive
- Screening all pregnant women for tobacco use and provide pregnancy-tailored counseling to those who screen positive (1)
- The USPSTF recommends that clinicians provide interventions, including education or brief counseling to prevent initiation of tobacco use among school-aged children and adolescents (1)[B].