Editing Tobacco (section)

====Chemicals====
Tobacco smoking harms health because of the toxic chemicals in tobacco smoke, including [[carbon monoxide]], [[cyanide]], and [[carcinogens]], which have been proven to cause heart and lung diseases and cancer.
Thousands of different substances in cigarette smoke, including [[polycyclic aromatic hydrocarbons]] (such as [[benzopyrene]]), [[formaldehyde]], [[cadmium]], [[nickel]], [[arsenic]], [[tobacco-specific nitrosamines]], and [[phenols]] contribute to the harmful effects of smoking.<ref name="tobaccocontrol.bmj.com">{{cite journal|author=Proctor Robert N|year=2012|title=The history of the discovery of the cigarette-lung cancer link: evidentiary traditions, corporate denial, global toll|url=http://tobaccocontrol.bmj.com/content/21/2/87.full.pdf|journal=Tobacco Control|volume=21|issue=2|pages=87–91|doi=10.1136/tobaccocontrol-2011-050338|pmid=22345227|s2cid=2734836|doi-access=free}}</ref>

According to the World Health Organization, tobacco is the single greatest cause of preventable death globally.<ref name="who 2008 mpower"/> WHO estimates that tobacco caused 5.4&nbsp;million deaths in 2004<ref name="WHO 2004">{{Cite book |last1=Mathers |first1=Colin |author-link=Colin Mathers |last2=Boerma |first2=Ties |last3=Fat |first3=Doris Ma |date=2008 |title=The Global Burden of Disease : 2004 Update |url=https://apps.who.int/iris/handle/10665/43942 |archive-url=https://web.archive.org/web/20220207114854/https://apps.who.int/iris/bitstream/handle/10665/43942/9789241563710_eng.pdf?sequence=1&isAllowed=y |archive-date=February 7, 2022 |access-date=October 6, 2022 |publisher=[[World Health Organization]] |hdl=10665/43942 |isbn=978-92-4-156371-0 |oclc=264018380}}</ref> and 100 million deaths over the course of the 20th century.<ref name="who 2008 mpower"/> Similarly, the United States [[Centers for Disease Control and Prevention]] describe tobacco use as "the single most important preventable risk to human health in developed countries and an important cause of premature death worldwide."<ref name="fn1">{{cite web |url=https://www.cdc.gov/tobacco/quit_smoking/you_can_quit/nicotine.htm |title=Nicotine: A Powerful Addiction |work=Centers for Disease Control and Prevention |archive-url=https://web.archive.org/web/20090226225821/http://www.cdc.gov/tobacco/quit_smoking/you_can_quit/nicotine.htm |archive-date=February 26, 2009}}</ref> Due to these health consequences, it is estimated that a 10 hectare (approximately 24.7 acre) field of tobacco used for cigarettes causes 30 deaths per year – 10 from lung cancer and 20 from cigarette-induced diseases like cardiac arrest, gangrene, bladder cancer, mouth cancer, etc.<ref>{{cite journal |last1=Proctor |first1=Robert N |title=The history of the discovery of the cigarette–lung cancer link: evidentiary traditions, corporate denial, global toll: Table 1 |journal=Tobacco Control |date=March 2012 |volume=21 |issue=2 |pages=87–91 |doi=10.1136/tobaccocontrol-2011-050338 |pmid=22345227 |doi-access=free }}</ref>

The harms caused by inhaling tobacco smoke include diseases of the [[heart]] and [[lung]]s, with smoking being a major risk factor for [[myocardial infarction|heart attacks]], [[stroke]]s, [[chronic obstructive pulmonary disease]] (emphysema), and [[cancer]] (particularly cancers of the [[Lung cancer|lungs]], [[Cancer of the larynx|larynx, mouth]], and [[pancreatic cancers|pancreas]]). Cancer is caused by inhaling carcinogenic substances in tobacco smoke.

Inhaling secondhand tobacco smoke (which has been exhaled by a smoker) can cause lung cancer in nonsmoking adults. In the United States, about 3,000 adults die each year due to lung cancer from secondhand smoke exposure. Heart disease caused by secondhand smoke kills around 46,000 nonsmokers every year.<ref>{{Cite web |title=Secondhand Smoke |url=http://betobaccofree.hhs.gov/health-effects/secondhand-smoke/index.html |url-status=deviated |archive-url=https://web.archive.org/web/20140920231625/http://betobaccofree.hhs.gov/health-effects/secondhand-smoke/index.html |archive-date=September 20, 2014 |website=BeTobaccoFree |publisher=[[United States Department of Health and Human Services|Health and Human Services]]}}</ref>

In children, exposure to secondhand tobacco smoke is associated with a higher incidence and severity of respiratory illnesses, middle ear disease, and asthma attacks.  Each year in the United States, secondhand smoke exposure causes 24,500 infants to be born with low birthweight, 71,900 preterm births, 202,300 episodes of asthma, and 790,000 health care visits for ear infections.<ref>{{Cite report |url=https://escholarship.org/uc/item/8hk6960q |title=Proposed Identification of Environmental Tobacco Smoke as a Toxic Air Contaminant |last=Air Resources Board |date=June 24, 2005 |publisher=[[California Environmental Protection Agency]] |access-date=October 6, 2022 |archive-url=https://web.archive.org/web/20211127163329/https://escholarship.org/content/qt8hk6960q/qt8hk6960q.pdf?t=krnni4 |archive-date=November 27, 2021}}</ref>

The addictive alkaloid [[nicotine]] is a [[stimulant]], and popularly known as the most characteristic constituent of tobacco. In drug effect preference questionnaires, a rough indicator of addictive potential, nicotine scores almost as highly as opioids.<ref>{{Cite book |url=http://ww1.drugabuse.gov/pdf/monographs/92.pdf |title=Testing for Abuse Liability of Drugs in Humans |publisher=[[National Institute on Drug Abuse]], [[United States Department of Health and Human Services|Health and Human Services]] |year=1989 |editor-last=Fischman |editor-first=Marian W. |editor-link=Marian Fischman |location=Rockville, MD |page=79 |id=NIDA Research Monograph No. 92 |editor-last2=Mello |editor-first2=Nancy K. |archive-url=https://web.archive.org/web/20161222041641/http://ww1.drugabuse.gov/pdf/monographs/92.pdf |archive-date=December 22, 2016 |url-status=dead}}</ref> Users typically develop [[Physiological tolerance|tolerance]] and [[Chemical dependency|dependence]].<ref>{{cite web |url=http://www.tobaccofacts.org/tob_truth/soaddictive.html |title=Tobacco Facts – Why is Tobacco So Addictive? |publisher=Tobaccofacts.org |access-date=September 18, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20070314185950/http://www.tobaccofacts.org/tob_truth/soaddictive.html |archive-date=March 14, 2007}}</ref><ref>{{cite web |url=http://www.stanford.edu/group/SICD/PhilipMorris/pmorris.html |title=Philip Morris Information Sheet |publisher=[[Stanford University]] |access-date=September 18, 2008 |archive-url=https://web.archive.org/web/20080405204802/http://www.stanford.edu/group/SICD/PhilipMorris/pmorris.html  |archive-date=April 5, 2008}}</ref> Nicotine is known to produce [[conditioned place preference]], a sign of psychological enforcement value.<ref>{{cite journal |last1=Le Foll |first1=Bernard |last2=Goldberg |first2=Steven R. |title=Nicotine induces conditioned place preferences over a large range of doses in rats |journal=Psychopharmacology |date=April 2005 |volume=178 |issue=4 |pages=481–492 |doi=10.1007/s00213-004-2021-5 |pmid=15765262 |s2cid=34966899 }}</ref> In one medical study, tobacco's overall harm to user and self was determined at three percent below cocaine, and 13 percent above amphetamines, ranking sixth most harmful of the 20 drugs assessed.<ref>{{cite journal |last1=Nutt |first1=David J |last2=King |first2=Leslie A |last3=Phillips |first3=Lawrence D |title=Drug harms in the UK: a multicriteria decision analysis |journal=The Lancet |date=November 2010 |volume=376 |issue=9752 |pages=1558–1565 |doi=10.1016/S0140-6736(10)61462-6 |citeseerx=10.1.1.690.1283 |pmid=21036393 |s2cid=5667719 }}</ref>

Tobacco also contains 2,3,6-Trimethyl-1,4-naphthoquinone (sometimes called 2,3,6-TQ and TMN) which is a reversible [[monoamine oxidase inhibitor]] of type A and B with a binding affinity somewhat similar to that of [[clorgyline]] and [[deprenyl]]. It is a stronger dopamine releasing agent than nicotine and inhibits dopamine metabolism from its MAOI activity.<ref>{{cite thesis | url=https://repository.nwu.ac.za/handle/10394/590 | title=Smoking and brain dopaminergic neurochemistry | date=March 25, 2024 | publisher=North-West University | type=Thesis | vauthors = McAfee G }}</ref><ref>{{cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/1_4-Naphthalenedione_-2_3_6-trimethyl | title=1,4-Naphthalenedione, 2,3,6-trimethyl- }}</ref> Tobacco also contains [[Harmine]] and Norharmine which is a reversible MAO-A inhibitor.<ref>{{cite journal | pmc=6592107 | date=2019 | title=Effect of Harmine on Nicotine-Induced Kidney Dysfunction in Male Mice | journal=International Journal of Preventive Medicine | volume=10 | page=97 | doi=10.4103/ijpvm.IJPVM_85_18 | doi-access=free | pmid=31360344 | vauthors = Salahshoor MR, Roshankhah S, Motavalian V, Jalili C }}</ref><ref>{{cite journal | url=https://pubmed.ncbi.nlm.nih.gov/28057462/ | pmid=28057462 | date=2017 | title=Monoamine oxidase inhibitory activity in tobacco particulate matter: Are harman and norharman the only physiologically relevant inhibitors? | journal=Neurotoxicology | volume=59 | pages=22–26 | doi=10.1016/j.neuro.2016.12.010 | vauthors = Truman P, Grounds P, Brennan KA | bibcode=2017NeuTx..59...22T }}</ref><ref>{{cite journal | doi=10.3389/fnmol.2022.925272 | doi-access=free | title=Harmane Potentiates Nicotine Reinforcement Through MAO-A Inhibition at the Dose Related to Cigarette Smoking | date=2022 | journal=Frontiers in Molecular Neuroscience | volume=15 | pmid=35832393 | pmc=9271706 | vauthors = Ding Z, Li X, Chen H, Hou H, Hu Q }}</ref><ref>{{cite journal | url=https://www.jstor.org/stable/4253715 | jstor=4253715 | title=Nicotiana an Hallucinogen? | journal=Economic Botany | date=March 25, 1976 | volume=30 | issue=2 | pages=149–151 | doi=10.1007/BF02862960 | vauthors = Janiger O, De Rios MD | bibcode=1976EcBot..30..149J | url-access=subscription }}</ref> The MAO-A activity of tobacco alkaloids have been thought to play a role in the addictive qualities of tobacco.<ref>{{cite journal | url=https://jamanetwork.com/journals/jamapsychiatry/fullarticle/1107244 | doi=10.1001/archgenpsychiatry.2011.82 | title=Monoamine Oxidase a Binding in the Prefrontal and Anterior Cingulate Cortices During Acute Withdrawal from Heavy Cigarette Smoking | date=2011 | journal=Archives of General Psychiatry | volume=68 | issue=8 | pages=817–826 | pmid=21810646 | vauthors = Bacher I, Houle S, Xu X, Zawertailo L, Soliman A, Wilson AA, Selby P, George TP, Sacher J, Miler L, Kish SJ, Rusjan P, Meyer JH | url-access=subscription }}</ref>