Tobacco



Tobacco


Mark L. Rubinstein

Judith J. Prochaska





“Tobacco use is a pediatric epidemic, around the world as well as in the United States.”

Regina Benjamin, M.D., M.B.A. Surgeon General 20121

More than 80% of all cigarette smokers start before the age of 18, and the majority of these will be addicted by young adulthood. Great strides have been made in limiting environmental exposure to tobacco smoke and banning direct marketing and sales of cigarettes to youth, resulting in a decline in adolescent and young adult (AYA) cigarette use in the US. However, challenging these public health efforts is the evolving tobacco market, with greater promotion of cigarillos (mini-cigars distinguishable from cigarettes only by their tobacco leaf rolling paper) and electronic or e-cigarettes (battery powered devices that generate an aerosol for inhalation typically containing nicotine). Both cigarillos and e-cigarettes are available for single purchase in a variety of child-friendly candy-flavorings (e.g., chocolate, bubble gum, cotton candy), and alterable for smoking other substances (e.g., marijuana). Use of cigarillos and e-cigarettes is on the rise among AYAs in some areas, generating concern that these products may represent a new gateway into tobacco smoking. The role of health care providers in immunizing their young patients from initiation of smoking and assisting those patients or the parents of their patients who already smoke to stop is critical.


PREVALENCE


Use among Adolescents

Tobacco use by adolescents remains a serious public health problem with roughly 1,000 American teenagers becoming regular smokers each day. In the 2014 Monitoring the Future (MTF) study of adolescents, there were two major findings:



  • Cigarette smoking continues to decline and is now at the lowest levels recorded in the history of the survey.


  • e-Cigarettes: This new product has made significant inroads among adolescents. Its prevalence among adolescents is now higher than the prevalence of tobacco cigarette smoking.

Past-month smoking among youth younger than 18 years declined from a peak of 36% in 1996 to 1997 to 18% in 2011 (Fig. 65.1). In the 2014 MTF survey (www.monitoringthefuture.org), 30-day prevalence of cigarette use reached a peak in 1996 in grades 8 and 10. Between 1996 and 2014, “current smoking” fell dramatically in these grades (by 81% and 77%, respectively). This decline slowed in recent years, and in 2010 there was a suggestion of a slight increase in smoking rates among 8th and 10th graders. However, use in these grades declined further between 2011 through 2014. Among 12th graders, peak use occurred in 1997 at 37%, and declined more modestly since then to 14% in 2014 (a 63% decline). In the 2014 survey, 4% of 8th graders, 7.2% of 10th graders, and 13.6% of 12th graders reported smoking one or more cigarettes during the previous 30 days. Declines in “daily smoking” are seen across all grades (currently 1% of 8th graders, 3.4% of 10th graders, and 5.8% of 12th graders).


Gender and Race

In the 2014 MTF study, there was more use among 12th grade males (15%) than females (12%) and among non-Hispanic Whites (18%) compared to Hispanics (11%) and Blacks (9%).


Smokeless Tobacco

Use of smokeless tobacco also has declined, with current rates for 30-day use in the 2014 MTF survey being 3% among 8th graders, 5.3% among 10th graders, and 8.4% among 12th graders.


Other Studies

The same trends in the prevalence of smoking among youth have been observed in the Centers for Disease Control and Prevention’s (CDC’s) biannual school-based Youth Risk Behavior Surveillance System (YRBSS; www.cdc.gov/HealthyYouth/yrbs) and the Substance Abuse and Mental Health Services Association (SAMHSA) non-school-based sample of adolescents in the biannual National Survey on Drug Use and Health (NSDUH; http://oas.samhsa.gov/nsduh.htm). While cigarette use has declined, there has been a significant increase in cigar use among Blacks adolescents, from 7% in 2009 to 12% in 2011.2


Tobacco Use among College Students and Young Adults

Young adults aged 18 to 24 have the highest prevalence of smoking and use of noncigarette, nicotine-containing tobacco products than any other age-group.3 For both male and female college students, cigarettes remain the most commonly used tobacco product. Smokeless tobacco, traditional cigars, and pipes are less common, while flavored cigarillos, hookah (water pipe), and e-cigarettes are gaining in popularity. According to the 2013 National Health Interview Survey, among young adults aged 18 to 24, 23% of men and 17% of women are current smokers.4 The 2013 MTF survey (Table 65.1) yielded similar results among young adults aged 19 to 28, with 20% reporting current smoking.5 Whites have the highest use of tobacco products, followed by Hispanics, Asians, and Blacks.4
College students who use tobacco are more likely to be single, White, and engaged in other risky behaviors involving substance use and sexual activity. Based on the Surgeon General report from 2012, of every three young smokers (i.e., AYAs), one will quit and one will die from tobacco-related causes.1 The tobacco industry has overtly and heavily targeted young adult smokers, sponsoring events in bars and clubs, musical events, and movies popular with young adults.






FIGURE 65.1 Trends in current cigarette smoking among high school students and adults, in the US, 1965 to 2011. (From the Centers for Disease Control and Prevention. Updated November 2013. Available at http://www.cdc.gov/tobacco/data_statistics/tables/trends/cig_smoking/)


FACTORS ASSOCIATED WITH YOUTH TOBACCO USE

Factors related to smoking initiation for boys and girls include low educational aspirations or attainment; low self-esteem or ongoing stress or depression; risk-taking; minimizing perceived hazards of smoking; and favorable attitudes toward smoking or smokers. Other variables associated with adolescent smoking include peer, parental, and sibling smoking; perceived parental or peer support for smoking; lower socioeconomic status or parental educational attainment; a history of abuse; exposure to tobacco advertising on the Internet or in the movies; and accessibility, availability, and price of tobacco products.1,6 There are also gender-specific factors associated with smoking. For example, girls are more likely to smoke cigarettes for weight control, while teenage boys may smoke for a sense of adventure or daring.6 Youth who identify as gay, lesbian, or bisexual smoke at rates far greater than those of their straight counterparts.7


NICOTINE ADDICTION AND HEALTH CONSEQUENCES


Addiction

Nicotine is one of the most addictive substances known. Tobacco use by adolescents, which may have started primarily for psychosocial reasons, can become a serious drug addiction. Preteens and early adolescents may believe that there are benefits to smoking and underestimate the addictive nature of cigarettes. Yet, initial symptoms of nicotine dependence occur in some teens, within days to weeks of onset of use.


Modes of Action

Nicotine seems to function as a positive reinforcer through its actions on nicotinic acetylcholine receptors in the mesocorticolimbic dopamine pathway. Stimulation of brain dopamine systems is of great importance for the rewarding and dependence-producing properties of nicotine.8 Abstinence from nicotine is associated with depletion of dopamine and other neurotransmitters, which may cause numerous withdrawal symptoms, including anxiety, irritability, and cravings.9 There are likely genetic factors (e.g., genetic variants in the CYP2A6 gene that influence the rate at which a smoker clears nicotine) in an individual’s susceptibility to tobacco addiction as well as to response to the various pharmacologic treatments.10 This is an active area of ongoing research.


Pharmacology



  • Each cigarette delivers 1 to 2 mg of nicotine to the smoker.


  • Each dose of the drug acts on the user within seconds of being inhaled.

Plasma concentrations of nicotine decline in a biphasic manner. Typically, the initial half-life is 2 to 3 minutes, and the terminal half-life is 30 to 120 minutes. Most nicotine is metabolized in the liver to cotinine. Cotinine has a plasma half-life that varies from approximately 16 to 20 hours. Nicotine and its metabolites are excreted by the kidneys; approximately 10% to 20% of the nicotine is eliminated unchanged in the urine.11


Effects of Other Compounds in Cigarettes

In addition to nicotine, cigarettes contain tar—a toxic compound. Cigarettes usually contain thousands of other chemicals, many poisonous and cancer causing, including arsenic, ammonia, benzene, cadmium, carbon monoxide, cyanide, formaldehyde, lead, nitrosamines, polonium, and polynuclear aromatic hydrocarbons.


Systemic Effects of Tobacco

The 2014 US Surgeon General’s report updated the list of diseases related to tobacco use and concluded that unless use rates decline, smoking will result in the premature death of 1 of every 13 or 5.6 million US children alive today. The 2014 report concluded that

smoking is even more dangerous than previously thought. Use of tobacco products can adversely affect virtually every organ system in the body (http://www.surgeongeneral.gov/library/reports/50-years-of-progress/). Some of these adverse effects include the following:








TABLE 65.1 Trends in 30-Day Prevalencea of Useb of Cigarettes for 8th, 10th, and 12th Graders, College Students, and Young Adults (Aged 19-28)






























































































































































1991


1992


1993


1994


1995


1996


1997


1998


1999


2000


2001


2002


2003


2004


2005


2006


2007


2008


2009


2010


2011


2012


2013


8th Grade


14.3


15.5


16.7


18.6


19.1


21.0


19.4


19.1


17.5


14.6


12.2


10.7


10.2


9.2


9.3


8.7


7.1


6.8


6.5


7.1


6.1


4.9


4.5


10th Grade


20.8


21.5


24.7


25.4


27.9


30.4


29.8


27.6


25.7


23.9


21.3


17.7


16.7


16.0


14.9


14.5


14.0


12.3


13.1


13.6


11.8


10.8


9.1


12th Grade


28.3


27.8


29.9


31.2


33.5


34.0


36.5


35.1


34.6


31.4


29.5


26.7


24.4


25.0


23.2


21.6


21.6


20.4


20.1


19.2


18.7


17.1


16.3


College Students


23.2


23.5


24.5


23.5


26.8


27.9


28.3


30.0


30.6


28.2


25.7


26.7


22.5


24.3


23.8


19.2


19.9


17.9


17.9


16.4


15.2


12.5


14.0


Young Adults


28.2


28.3


28.0


28.0


29.2


30.1


29.9


30.9


30.3


30.1


30.2


29.2


28.4


29.2


28.6


27.0


26.2


24.6


23.3


22.4


21.3


19.7


20.0


aNumbers are percentages.

bRefers to any use.


From Johnston LD, O’Malley PM, Miech RA, et al. Monitoring the future national results on drug use: 1975-2014: overview, key findings on adolescent drug use. Ann Arbor: Institute for Social Research, The University of Michigan, 2015. Available at http://monitoringthefuture.org//pubs/monographs/mtf-vol2_2013.pdf; Table 2.3.


Sep 7, 2016 | Posted by in ONCOLOGY | Comments Off on Tobacco

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