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Line 1: − '''Tobacco''' is a [[plant]] used for smoking and for medicine. Its recreational qualities were discovered by [[Native American]]s 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. But recently it has also been discovered to have some positive health benefits, including a reduced risk of Alzheimer's disease and Parkinson's disease and a reduced risk of Kaposi's sarcoma. + − − == 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.<ref>One of the first papers to recognize that smoking causes lung cancer was published in 1957.[http://cancerres.aacrjournals.org/cgi/reprint/17/10/981.pdf]</ref> Tobacco companies have genetically modified tobacco plants and added toxic [[chemical]]s 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]]<ref>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</ref> (i.e., higher doses are required to achieve the same effect), and [[withdrawal]]<ref>Hughes, J.R., Higgins, S.T., & Bickel, W.K. (1994). Nicotine withdrawal versus other drug withdrawal syndromes: Similarities and dissimilarities. ''Addiction, 89'', 1461-1470</ref> symptoms (e.g., irritability, restlessness, nicotine cravings) occur when use is discontinued. Intake elicits acute increases in heart rate and blood pressure<ref>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.''</ref>, 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<ref>Miller, M.S., & Cocores, J.A. (1993). Nicotine dependence: Diagnosis, chemistry and pharmacologic treatments. ''Pediatrics in Review, 14'', 275-279.</ref>, and reaches the brain about seven seconds after it is inhaled in cigarette smoke<ref>Benowitz, N.L. (1991). Pharmacodynamics of nicotine: Implications for rational treatment of nicotine addiction. ''British Journal of Addiction, 86'', 495-499.</ref>. After reaching the brain, it stimulates the release of a number of [[neurotransmitters]], including [[dopamine]]<ref>Stolerman, I.P., & Shoaib, M. (1991). The neurobiology of tobacco addiction. ''Trends in Pharmacological Science, 12'', 467-473.</ref>, [[norepinephrine]]<ref>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.</ref>, [[serotonin]]<ref>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.</ref>, and [[acetylcholine]]<ref>Summers & Giacobini, 1995.</ref>. 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. For example, smoking reduces the risk of Kaposi's sarcoma, as well as breast cancer among women at high risk for it due to the presence of the BRCA gene. Nicotine also appears to have therapeutic benefit for individuals with ulcerative colitis, one form of epilepsy, and neurological disorders such as Alzheimer's Dementia. − − 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 receieves 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<ref>Centers for Disease Control (2005). Cigarette smoking among adults - United States, 2004. ''Morbidity & Mortality Weekly Report, 54''', 1121-1124</ref>, and about 438,000 Americans die annually due to the effects of smoking; about 38,000 of these deaths are attributed to secondhand smoke<ref>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.</ref>. While the prevalence of smoking has dropped dramatically in the past 50 years, the rate at which the prevalence is decreasing has slowed substantially<ref>Hughes, J. R., & Brandon, T. H. (2003). A softer view of hardening. ''Nicotine & Tobacco Research, 5'', 961-962.</ref> Additionally, the rate of smoking in adolescents and young adults has been increasing since the mid-1990s<ref>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.</ref>. There are nearly 5,000 different chemicals in cigarette smoke, including over 60 [[carcinogens]]<ref>Hecht, S. (2006). Cigarette smoking: Cancer risks, carcinogens, and mechanisms. ''Archives of Surgery, 391'', 603-613</ref>. − − '''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<ref>Hecht, 2006.</ref>. Smoking increases the risk of oral, pharyngeal, esophageal, laryngeal, lung, uterine, cervical, urinary, and kidney cancers<ref>http://www.cdc.gov/tobacco/health_effects/cancer.htm</ref>. − − 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<ref>http://www.cdc.gov/tobacco/health_effects/heart.htm</ref>. Smoking also negatively impacts the respiratory system. Approximately 90% of all deaths from chronic lung diseases are the result of smoking<ref>http://www.cdc.gov/tobacco/health_effects/respiratory.htm</ref>. − − == 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.<ref>California Environmental Protection Agency (2005, June). Health Effects of Exposure to Tobacco Smoke.</ref>. According the the [[Surgeon General]], even short-term exposure to secondhand smoke can have harmful effects on cardiovascular functioning<ref>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 [http://www.surgeongeneral.gov/library/secondhandsmoke/factsheets/factsheet6.html]</ref>. 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"<ref>http://www.imperial-tobacco.com/index.asp?pageid=64&subsection=env_tobacco_smoke. Accessed April 26, 2007.</ref>. 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"<ref>http://www.phillipmorrisusa.com/en/health_issues/secondhand_smoke.asp. Accessed April 26, 2007.</ref>. − − == 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.<ref>''[[FDA v. Brown & Williamson Tobacco Corp.]]'', 529 U.S. 120 (2000).</ref> − − == References == − <references/>
Replacing page with '[http://www.wikipedia.org.en/tobacco/]'
[http://www.wikipedia.org.en/tobacco/]