Tobacco

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Tobacco is a drug that is consumed by smoking or chewing. Its recreational qualities were discovered by Native Americans and passed on to Europeans after the establishment of Jamestown in 1607. Tobacco causes lung cancer. It also causes mouth and throat cancer and emphysema. It has more than forty carcinogens. Studies have shown that tobacco is more addictive than cocaine and even heroin.

Contents

History

The Native Americans were the first to use tobacco because tobacco only grew in the Americas. Tobacco when consumed in large quantities is a hallucinogen, therefore the Native Americans did not use it recreationally but instead used it as a hallucinogen during religious ceremonies. Tobacco was exported by John Rolfe, (husband of Pocahontas). It became known as a cash crop. The negative effects of tobacco such as lung cancer, bronchitis and foul breath are widely accepted today.[1] Tobacco companies have genetically modified tobacco plants and added toxic chemicals to their products to make them more addictive, thus making the modern cigarette much more toxic than the original cultivated plant.

Nicotine

Nicotine is an alkaloid in tobacco that is responsible for the addictive nature of cigarette smoking and other tobacco use. Regular nicotine consumption leads to tolerance[2] (i.e., higher doses are required to achieve the same effect), and withdrawal[3] symptoms (e.g., irritability, restlessness, nicotine cravings) occur when use is discontinued. Intake elicits acute increases in heart rate and blood pressure[4], as well as respiratory rate, but also decreases the volume of blood flow by causing the constriction of blood vessels. Nicotine in cigarette smoke is very easily absorbed through the lungs and buccal tissue in the oral cavity[5], and reaches the brain about seven seconds after it is inhaled in cigarette smoke[6]. After reaching the brain, it stimulates the release of a number of neurotransmitters, including dopamine[7], norepinephrine[8], serotonin[9], and acetylcholine[10]. The increased availability of these chemicals in the brain leads to feelings of pleasure and mild euphoria, as well as increased alertness and concentration. The half-life of nicotine is approximately two hours.

Medications containing nicotine are also used to help smokers who are trying to quit. These are referred to as nicotine replacement therapy (NRT). The idea behind NRT is that it allows smokers to break the behavioral component of their smoking habit (e.g., becoming used to not smoking while driving) while gradually reducing the amount of nicotine in their bloodstream, thus minimizing the effects of physiological nicotine withdrawal. Several different forms of NRT are available, including a transdermal patch, chewing gum, and nasal spray. Nicotine has also been found to be a useful treatment for certain physical conditions, though the mechanisms are not well understood. Smoking has been associated with a lower risk of Kaposi's sarcoma[11]. Nicotine also appears to have therapeutic benefit for individuals with ulcerative colitis and one form of epilepsy.

Nicotine has been shown in some medical studies to be more addictive than cocaine and even heroin. Tobacco often occurs along with cocaine use because the nicotine in tobacco greatly enhances the euphoria one receives from cocaine.

Image:Nicotine.gif

Tobacco Products

Cigarettes. Cigarettes are the most commonly used tobacco product. Approximately one of every five American adults is a current smoker[12], and about 438,000 Americans die annually due to the effects of smoking; about 38,000 of these deaths are attributed to secondhand smoke[13]. While the prevalence of smoking has dropped dramatically in the past 50 years, the rate at which the prevalence is decreasing has slowed substantially[14] Additionally, the rate of smoking in adolescents and young adults has been increasing since the mid-1990s[15]. There are nearly 5,000 different chemicals in cigarette smoke, including over 60 carcinogens[16].

Cigars.


Smokeless tobacco.

Health Effects

Smoking has a significant negative health impact, and causes many dangerous and fatal conditions, including cancers, heart disease, and respiratory disease.

It has been estimated that cigarette smoking is responsible for 28% of all deaths in developed countries in the 35-69 age group, as well as 35% of all cancer deaths and 28% of all deaths due to vascular diseases[17]. Smoking increases the risk of oral, pharyngeal, esophageal, laryngeal, lung, uterine, cervical, urinary, and kidney cancers[18].

Coronary heart disease is one of the biggest causes of death in the United States, and is 2-4 more likely in smokers than nonsmokers. Smokers are also 10 times more likely to develop peripheral vascular disease, which is a narrowing of the arteries. Additionally, smokers are twice as vulnerable to a stroke compared with nonsmokers[19]. Smoking also negatively impacts the respiratory system. Approximately 90% of all deaths from chronic lung diseases are the result of smoking[20].

In addition, smoking has been shown to double the risk of Alzheimer's Disease[21].

Secondhand Smoke

Secondhand smoke refers to smoke that is inhaled by nonsmokers from the environment. It is a combination of smoke given off by cigarettes and other smoking implements that is not inhaled by smokers, as well as the smoke exhaled by smokers. The U.S. Environmental Protection Agency has classified secondhand smoke as a Group A carcinogen, meaning that it is known to cause cancer in humans. It has been reported that secondhand smoke causes 3,600 annual lung cancer deaths and between 22,700 and 69,600 heart disease deaths annually in the U.S.[22]. According the the Surgeon General, even short-term exposure to secondhand smoke can have harmful effects on cardiovascular functioning[23]. Some tobacco companies have disputed the findings regarding harm caused by secondhand smoke. For example, Imperial Tobacco's website states "...it is our view that the scientific evidence, taken as a whole, is insufficient to establish that other people's tobacco smoke is a cause of any disease"[24]. Other tobacco companies have acknowledged that secondhand smoke can be harmful, including Phillip Morris: "Public health officials have concluded that secondhand smoke from cigarettes causes disease...Phillip Morris USA believes that the public should be guided by the conclusions of public health officials...[and] that the conclusions of public health officials concerning environmental tobacco smoke are sufficient to warrant measures that regulate smoking in public places"[25].

Regulation

In 2000, the U.S. Supreme Court ruled by a narrow margin of 5-4 that the FDA lacked authority to regulate tobacco products.[26]

References

  1. ↑ One of the first papers to recognize that smoking causes lung cancer was published in 1957.[1]
  2. ↑ Porchet, H. C., Benowitz, N. L., & Sheiner, L. B. (1988). Pharmacodynamic model of tolerance: Application to nicotine. Journal of Pharmacology & Experimental Therapeutics, 244, 231-236
  3. ↑ Hughes, J.R., Higgins, S.T., & Bickel, W.K. (1994). Nicotine withdrawal versus other drug withdrawal syndromes: Similarities and dissimilarities. Addiction, 89, 1461-1470
  4. ↑ Benowitz, N.L., Jacob, P., Jones, R.T., & Rosenberg, J. (1982). Interindividual variability in the metabolism and cardiovascular effects of nicotine in man. Journal of Pharmacology & Experimental Therapeutics, 221, 368-372.
  5. ↑ Miller, M.S., & Cocores, J.A. (1993). Nicotine dependence: Diagnosis, chemistry and pharmacologic treatments. Pediatrics in Review, 14, 275-279.
  6. ↑ Benowitz, N.L. (1991). Pharmacodynamics of nicotine: Implications for rational treatment of nicotine addiction. British Journal of Addiction, 86, 495-499.
  7. ↑ Stolerman, I.P., & Shoaib, M. (1991). The neurobiology of tobacco addiction. Trends in Pharmacological Science, 12, 467-473.
  8. ↑ Summers, K.L., & Giacobini, E. (1995). Effects of local and repeated systemic administration of (-)nicotine on extracellular levels of acetylcholine, norepinephrine, dopamine and serotonin in rat cortex. Neurochemical Research, 20, 753-759.
  9. ↑ Ribeiro, E.B., Bettiker, R.L., Bogdanov, M., & Wurtman, R.J. (1993). Effects of systemic nicotine on serotonin release in rat brain. Brain Research, 621, 311-318.
  10. ↑ Summers & Giacobini, 1995.
  11. ↑ http://dceg.cancer.gov/pdfs/goedert942002.pdf
  12. ↑ Centers for Disease Control (2005). Cigarette smoking among adults - United States, 2004. Morbidity & Mortality Weekly Report, 54', 1121-1124
  13. ↑ Centers for Disease Control (2005). Annual smoking-attributable mortality, years of potential life lost, and productivity losses - United States, 1997-2001. Morbidity & Mortality Weekly Report, 54, 300-303.
  14. ↑ Hughes, J. R., & Brandon, T. H. (2003). A softer view of hardening. Nicotine & Tobacco Research, 5, 961-962.
  15. ↑ Wechsler, H., Rigotti, N., Gledhill-Hoyt, J., & Lee, H. (1998). Increased levels of cigarette use among college students: A cause for national concern. Journal of the American Medical Association, 280, 1673-1678.
  16. ↑ Hecht, S. (2006). Cigarette smoking: Cancer risks, carcinogens, and mechanisms. Archives of Surgery, 391, 603-613
  17. ↑ Hecht, 2006.
  18. ↑ http://www.cdc.gov/tobacco/health_effects/cancer.htm
  19. ↑ http://www.cdc.gov/tobacco/health_effects/heart.htm
  20. ↑ http://www.cdc.gov/tobacco/health_effects/respiratory.htm
  21. ↑ http://news.bbc.co.uk/1/hi/health/115829.stm
  22. ↑ California Environmental Protection Agency (2005, June). Health Effects of Exposure to Tobacco Smoke.
  23. ↑ The Health Consequences of Involuntary Exposure to Tobacco Smoke: 6 Major Conclusions of the Surgeon General Report. A Report of the Surgeon General, U.S. Department of Health and Human Services, 2006. Retrieved from [2]
  24. ↑ http://www.imperial-tobacco.com/index.asp?pageid=64&subsection=env_tobacco_smoke. Accessed April 26, 2007.
  25. ↑ http://www.phillipmorrisusa.com/en/health_issues/secondhand_smoke.asp. Accessed April 26, 2007.
  26. ↑ FDA v. Brown and Williamson Tobacco Corp., 529 U.S. 120 (2000).
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