Tobacco smoking is the act of smoking tobacco products, especially cigarettes and cigars. Tobacco smoking is considered a significant cause of human health problems, especially lung cancer, emphysema, and other disorders.

The practice of smoking tobacco originated among American Indians in North America, where tobacco is native. It was adopted by many Europeans following the colonization of the Americas. Today, it is widespread throughout the world. According to the World Health Organization, it is most common in east Asia, where as many as two-thirds of all adult males smoke tobacco. Because of concern over the health hazards of smoking, the practice has rapidly declined in recent years in the United States and western Europe.

Tobacco may be smoked in several forms, the most common being the cigarette, the cigar, and the pipe. Cigarette smoking is by far the most common. Pipes and cigars are less common, and are used almost exclusively by men.

In the case of cigarette smoking, smoke is inhaled into the lungs. Tobacco smoke contains nicotine, which forms a strong physical and psychological chemical dependence (addiction). According to the Centers for Disease Control and Prevention, nicotine is a "very addictive drug" that can be "as addictive as heroin or cocaine."¹ Dependence is strongest when tobacco smoke is inhaled into the lungs and increases with quantity and speed of nicotine absorption.

Lighting the tobacco is usually done with a lighter or match. One of the most common favors asked from a stranger is for a light; it is also done as a pretext to start a conversation. Asking another smoker, even a stranger, for a cigarette is also a commonly accepted social gesture; it is considered bad form to refuse, except in the cases where there is only one cigarette left, or if the pack of cigarettes is unopened. Although many smokers consider smoking to be a relaxing, pleasurable, social activity, others view it as a bad habit. Some smokers view the long-term risks of smoking as balanced by its immediate rewards, while others deny the risks altogether.

History

Tobacco smoking, using both pipes and cigars, was common to many Native American cultures of the Americas. It is depicted in the art of the Classic-era Maya civilization about 1,500 years ago. The Mayas smoked tobacco and also mixed with lime and chewed it in a snuff-like substance. Among the Mayas tobacco was used as an all-purpose medicine, and was widely belived to have magical powers, being used in divinations and talismans. It was also burned a sacrifice to the gods; a tobacco gourd was worn as a badge by midwives.

With the arrival of the Europeans in the New World in the late 15th century, tobacco smoking was brought to Europe, and from there spread to the rest of the world.

The cigarette was less common than the cigar or the smoking pipe until the early 20th century, when cheap mechanically made cigarettes became common. Tobacco companies succeeded in having their product included in military rations during World War I, where under the stress of warfare many soldiers took up smoking, becoming habitual smokers. After the war, during the Roaring Twenties, cigarette smoking was portrayed in advertising as part of a glamorous carefree lifestyle. This image continued to be prevalent to some degree until the 1950s and 1960s, when the medical community and government (particularly in the United States) began a campaign to reduce the degree to which smoking damaged public health. In recent years tobbaco smoking in many regions of the world has dramatically dropped.

Health effects

It has been scientifically established that "tobacco use is the single most important preventable risk to human health in developed countries and an important cause of premature death worldwide".¹

An indirect public health problem posed by cigarettes is that of accidental fires, usually linked with consumption of alcohol. Numerous cigarette designs have been proposed, some by tobacco companies themselves, which would extinguish a cigarette left unattended for more than a minute or two, thereby reducing the risk of fire. However the tobacco companies have historically resisted this idea, on the grounds that the nuisance involved in having to relight a cigarette left untouched for too long would reduce their sales. In fact, untreated tobacco formed into a cigarette will extinguish itself relatively quickly if left alone, and as a result cigarette tobacco is treated chemically to allow it to smolder indefinitely.

The main health risks in tobacco smoking pertain to diseases of the cardiovascular system, in particular smoking being a major risk factor for a myocardial infarction (heart attack), diseases of the respiratory tract such as Chronic Obstructive Pulmonary Disease (COPD) and emphysema, and cancer, particularly lung cancer and cancers of the larynx and tongue. Previous to World War I, lung cancer was considered to be a rare disease, which most physicians would never see during their career. With the postwar rise in popularity of cigarette smoking, however, came a virtual epidemic of lung cancer.

A person's increased risk of contracting disease is directly proportional to the length of time that a person continues to smoke as well as the amount smoked. However, if someone stops smoking, then these chances steadily although gradually decrease as the damage to their body is repaired.

Diseases linked to smoking tobacco cigarettes include:

• lung cancer and other cancers
• stroke
• peripheral vascular disease
• birth defects of pregnant smokers' offspring
• Buerger's disease (thromboangiitis obliterans)
• impotence
• chronic obstructive pulmonary disease, emphysema and chronic bronchitis in particular

Cigar and pipe smokers tend to inhale less smoke than cigarette smokers, so their risk of lung cancer is lower but is still several times higher than the risk for nonsmokers. Pipe and cigar smokers are also at risk for cancers of the oral cavity, larynx (voice box), or esophagus. Cancer of the mouth and jaw is also a risk for people who chew tobacco rather than smoke it. US President Ulysses S. Grant died in 1885 at age 63 after a long and painful public battle with throat cancer which was widely assumed at the time to be the result of his lifelong cigar habit, even though there was no scientific evidence yet of a link between smoking and cancer. His successor, President Grover Cleveland, was diagnosed in 1893 with cancer of the jaw which was successfully removed; the fact that the cancer was located in his left jaw, which was where he was usually seen to have a cigar clamped, was frequently remarked upon by the press and public.

It is generally assumed that the major motivational factor behind smoking is the nicotine it contains. However, the practice of ingesting the smoke from a smoldering leaf generates an enormous number of active chemical compounds, loosely lumped together as 'tar', many of which are biologically reactive and potential health dangers. (Nevertheless, the practice of chewing tobacco, which does not involve heat and therefore does not generate these compounds, is also carcinogenic). There are around 3000 chemicals found in tobacco smoke. Below are chemicals of known or supected carcinogenicity:

• Carcinogenic:
  • 4-Aminobiphenyl
  • Benzene
  • Cadmium
  • Chromium
  • 2-Naphthylamine
  • Nickel
  • Polonium-210
  • Radon
  • Vinyl chloride
  • Formaldehyde
• Probably carcinogenic to humans:
  • Acrylonitrile
  • Benzo[a]anthracene
  • Benzo[α]pyrene
  • 1,3-Butadiene
  • Dibenz(a,h)anthracene
  • N-Nitrosodiethylamine
  • N-Nitrosodimethylamine
• Possibly carcinogenic to humans:
  • Acetaldehyde
  • Benzo[b]fluoranthene
  • Benzo[j]fluoranthene
  • Benzo[k]fluoranthene
  • Dibenz[a,h]acridine
  • Dibenz[a,j]acridine
  • 7H-Dibenz[c,g]carbazole
  • Dibenzo(a,i)pyrene
  • Dibenzo(a,I)pyrene
  • 1,1-Dimethylhydrazine
  • Hydrazine
  • Indeno[1,2,3-cd]pyrene
  • Lead
  • Lead 210
  • 5-Methylchrysene
  • 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)
  • 2-Nitropropane
  • N-Nitrosodiethanolamine
  • N-Nitrosomethylethylamine
  • N-Nitrosomorpholine
  • N'-Nitrosonornicotine (NNN)
  • N-Nitrosopyrrolidine
  • Quinoline
  • iv ortho-Toluidine
  • Urethane (Ethyl Carbamate)

Long term exposure to other compounds in the smoke, such as carbon monoxide, cyanide, and other compounds that damage lung and arterial tissue, are believed to be responsible for cardiovascular damage and for loss of elasticity in the alveoli, leading to emphysema and COPD.

Radioactive components of tobacco

In addition to chemical, nonradioactive carcinogens, tobacco and tobacco smoke contain small amounts of lead-210 (210Pb) and polonium-210 (210Po) both of which are radioactive carcinogens. Lead 210 is a product of the decay of radium-226 and, in turn, its decay product, radon-222; lead 210 then decays to bismuth-210 and then to polonium 210, emitting beta particles in both steps. Tarry particles containing these elements lodge in the smokers' lungs where airflow is disturbed; the concentration found where bronchioles bifurcate is 100 times higher than that in the lungs overall. This gives smokers much more intense exposure than would otherwise be encountered. Polonium 210, for instance, emits high energy alpha particles which because of their large mass are considered to be incapable of penetrating the skin more than 40 micrometres deep, but do considerable damage (estimated at 100 times as much chromosome damage as a corresponding amount of other radiation) when a process such as smoking causes them to be emitted within the body, where all their energy is absorbed by surrounding tissue. (Polonium 210 also emits gamma rays).

The radioactive elements in tobacco are accumulated from the minerals in the soil, as with any plant, but are also captured on the sticky surface of the tobacco leaves in excess of what would be seen with plants not having this property. As might be expected, the radioactivity measured in tobacco varies widely depending on where and how it is grown. One study found that tobacco grown in India averaged only 0.09 pCi per gram of polonium 210, whereas tobacco grown in the United States averaged 0.516 pCi per gram. Another study of Indian tobacco, however, measured an average of 0.4 pCi of polonium 210 per cigarette, which also would be approximately a gram of tobacco. One factor in the difference between India and the United States may be the extensive use of apatite as fertilizer for tobacco in the United States, because it starves the plant for nitrogen, thereby producing more flavorful tobacco; apatite is known to contain radium, lead 210, and polonium 210. This would also account for increased concentration of these elements compared to other crops, which do not use this mineral as fertilizer.

Smoke from one cigarette is reported to contain 0.0263 - 0.036 pCi of polonium 210, which is equivalent to about 0.1 pCi per milligram of smoke; or about 0.81 pCi of lead 210 per gram of dry condensed smoke. The amount of polonium 210 inhaled from a pack of 20 cigarettes is therefore about 0.72 pCi. This seems to be independent of any form of filtering or 'low tar' cigarette. This concentration results in a highly significant increase in the body burden of these compounds. Compared to nonsmokers, heavy smokers have four times greater radioisotope density throughout their lungs. The polonium 210 content of blood in smokers averages 1.72 pCi per kilogram, compared to 0.76 pCi per kilogram in nonsmokers. Higher concentrations of polonium 210 are also found in the livers of smokers than nonsmokers. Polonium 210 is also known to be incorporated into bone tissue, where the continued irradiation of bone marrow may be a cause of leukemia, although this has not been proved as yet.

The alpha particle dosage from polonium 210 received by smokers of two packs a day has been measured at 82.5 millirads per day, which would total 752.5 rads per 25 years, 150 times higher than the approximately 5 rem received from natural background radiation over 25 years. Other estimates of the dosage absorbed over 25 years of heavy smoking range from 165 - 1,000 rem, all significantly higher than natural background. In the case of the less radioactive Indian tobacco referred to above, the dosage received from polonium 210 is about 24 millirads a day, totalling 219 rads over 25 years or still about 40 times the natural background radiation exposure. In fact, all these numbers of total body burden are misleadingly low, because the dosage rate in the immediate vicinity of the deposited polonium 210 in the lungs can be from 100 to 10,000 times greater than natural background radiation. Lung cancer is seen in laboratory animals exposed to approximately one fifth of this total dosage of polonium 210.

Whether the quantities of these elements are sufficient to cause cancer is still a matter of debate. Most studies of carcinogenicity of tobacco smoke involve painting tar condensed from smoke onto the skin of mice and monitoring for development of tumors of the skin, a relatively simple process. However, the specific properties of polonium 210 and lead 210 and the model for their action, as described above, do not permit such a simple assay and require more difficult studies, requiring dosage of the mice in a manner mimicing smoking behavior of humans and monitoring for lung cancer, more difficult to observe as it is internal to the mouse.

Some researchers suggest that the degree of carcinogenicity of these radioactive elements is sufficient to account for most, if not all, cases of lung cancer related to smoking. In support of this hypothetical link between radioactive elements in tobacco and cancer is the observation that bladder cancer incidence is also proportional to the amount of tobacco smoked, even though nonradioactive carcinogens have not been detected in the urine of even heavy smokers; however, urine of smokers contains about six times more polonium 210 than that of nonsmokers, suggesting strongly that the polonium 210 is the cause of the bladder carcinogenicity, and would be expected to act similarly in the lungs and other tissue. Furthermore, many of the lung cancers contracted by cigarette smokers are adenocarcinomas, which are characteristic of the type of damage produced by alpha particle radiation such as that of polonium 210. It has also been suggested that the radioactive and chemical carcinogens in tobacco smoke act synergistically to cause a higher incidence of cancer than each alone.

Skeptics of the role of polonium 210 in lung cancer note that it is soluble in water, and thus would be excreted (confirmed by the high polonium 210 concentrations in the urine of smokers, referred to above). However, the inhibition of the clearing action of the cilia in the respiratory tract by tobacco smoke, the stickiness of the particles of tar precipitated from the smoke, and deposits within the lung of insoluble lead 210 which then breaks down into polonium 210, have all been postulated as mechanisms by which polonium 210 exposure continues for long periods. Even after having stopped smoking for a year, concentrations of lead 210 and polonium 210 in rib bones and alveolar lung tissue remain twice as high in ex-smokers as in those who had never smoked.

Beneficial effects of smoking

Tobacco has sometimes been reported to have some positive health effects, presumably due to the effects of nicotine on the nervous system. Most notably, some studies have found that patients with Alzheimer's Disease are less likely to have smoked than the general population, which has been interpreted to suggest that smoking offers some protection against Alzheimer. However, the research in this area is limited and the results are mixed. Some studies show that smoking increases the risk of Alzheimer's Disease. A recent review of the available scientific literature concluded that the apparent decrease in Alzheimer risk may be simply due to the fact that smokers tend to die before reaching the age at which Alzheimer normally occurs. "Differential mortality is always likely to be a problem where there is a need to investigate the effects of smoking in a disorder with very low incidence rates before age 75 years, which is the case of Alzheimer's disease", it stated, noting that smokers are only half as likely as non-smokers to survive to the age of 80. [1] (http://www.blackwell-synergy.com/links/doi/10.1046/j.1360-0443.2002.00016.x/full/)

Smoking is more prevalent among the mentally ill than among the general population, and it has been theorized that nicotine may have a calming effect that alleviates some negative symptoms of psychiatric illnesses. Here, too, medical evidence is limited, and known therapeutic drugs are better suited than cigarettes for treatment of mental illness. Other studies have found that smoking is associated with slightly reduced incidence of endometrial cancer, hypertension during pregnancy, Parkinson's disease, and ulcerative colitis, but these possible health benefits are small compared to the much larger health risks with which smoking has been conclusively linked.

Nicotine and addiction

Nicotine is a powerful stimulant and is one of the main factors leading to the continued tobacco smoking. Although the amount of nicotine inhaled with tobacco smoke is quite small (most of the substance is destroyed by the heat) it is still sufficient to cause physical and/or psychological dependence. The amount of nicotine absorbed by the body from smoking depends on many factors, including the type of tobacco, whether the smoke is inhaled, and whether a filter is used. Despite the design of various cigarettes advertised and even tested on machines to deliver less of the toxic tar, studies show that when smoked by humans instead of machines, they deliver the same net amount of smoke, suggesting that smokers unconsciously adjust their smoking technique to dose themselves with a particular amount of nicotine. Ingesting a compound by smoking is one of the most rapid and efficient methods of introducing it into the bloodstream, second only to injection, which allows for the rapid feedback which supports the smokers' ability to titrate their dosage. On average it takes about seven seconds for the substance to reach the brain.

Although nicotine does play a role in acute episodes of some diseases (including stroke, impotence, and heart disease) by its stimulation of adrenaline release, which raises blood pressure, heart rate, and free fatty acids, the most serious longer term effects are more the result of the products of the smoldering combustion process. This has enabled development of various nicotine delivery systems, such as the nicotine patch or nicotine gum, that can satisfy the addictive craving by delivering nicotine without the harmful combustion byproducts. This can help the heavily dependent smoker to quit gradually, while discontinuing further damage to health.

Smoking and cardiovascular disease

Smoking also increases the chance of heart disease. Several ingredients of tobacco lead to the narrowing of blood vessels, increasing the likelihood of a blockage, and thus a heart attack or stroke. According to a study by an international team of researchers, people under 40 are five times more likely to have a heart attack if they smoke [2] (http://news.bbc.co.uk/2/hi/health/3590320.stm).

Other tobacco chemicals lead to high blood pressure. Also, some chemicals may damage the inside of arteries, for example making it possible for cholesterol to adhere to the artery wall, possibly leading to a heart attack.

Epidemiology of smoking

A team of British scientists headed by Richard Doll carried out a longitudinal study of 34,439 medical specialists from 1951 to 2001, generally called the "British doctors study" [3] (http://bmj.bmjjournals.com/cgi/content/abstract/bmj.38142.554479.AEv1). The study demonstrated that smoking decreased life expectancy by 10 years and that almost half of the smokers died from smoking (cancer, heart disease, and stroke). About 5,900 of the study participants are still alive and only 134 of them still smoke.

Effects on smokers

Smokers report a variety of physical and psychological effects from smoking tobacco. Those new to smoking will experience nausea, dizziness, and rapid heart beat. The negative symptoms will eventually vanish over time, with repeated use, as the body builds a tolerance to the nicotine. Nicotine is an unusual chemical because when absorbed slowly, it can act as a sedative and when absorbed quickly it can act as a stimulant. Pipe and cigar smokers usually experience more of the sedative/relaxation effect while cigarette smokers usually experience more of the stimulant effect.

In many respects, nicotine acts on the nervous system in a similar way to caffeine. Some writings have stated that smoking can also increase mental concentration. Most smokers say they enjoy smoking, which is part of the reason why many continue to do so even though they are aware of the health risks. Taste, smell, and visual enjoyment are also major contributions to the enjoyment of smoking, in addition to camaraderie with other smokers.

Experienced smokers, when denied access to nicotine, will often exhibit symptoms such as irritability, dry mouth, and rapid heart beat. Longer abstinence can lead to insomnia and even mild depression. Smokers abstaining from nicotine for approximately ten to twenty days will, eventually, eliminate the chemical dependence, although the psychological dependence may linger for months or even many years. Unlike illicit drugs and alcohol, nicotine does not alter a smoker's motor skills, cognition, judgment, or language abilities.

Smoking cessation

Many of tobacco's health effects can be minimised through smoking cessation. The "British doctors study" [4] (http://bmj.bmjjournals.com/cgi/content/abstract/bmj.38142.554479.AEv1) showed that those who stopped smoking before they reached 30 years of age lived almost as long as those who never smoked. It is also possible to help reduce the risks by reducing the frequency of smoking and by proper diet and exercise. Some research has indicated that some of the damage caused by smoking tobacco can be moderated with the use of antioxidants.

Smokers wanting to quit (or temporarily abstain from) smoking can use a variety of nicotine-containing tobacco subsitutes to temporarily lessen the physical withdrawal symptoms, the most popular being nicotine gum and lozenges. Nicotine patches are also used for smoking cessation. Discussing the problem with supportive people can also be helpful. In addition, there are lots of self-help books on the market, for example those by Allen Carr.

Moral aspects

Communal smoking of a sacred tobacco pipe was a universal ritual through Native America. Native Americans considered tobacco a sacred part of their religion. It was grown for ceremonial use and considered the ultimate sacred plant. Tobacco smoke was believed to carry prayers to the heavens.

In more modern times, even before the health risks of smoking were scientifically known, it was considered a filthy, harmful and immoral habit by some Christian preachers and social reformers. Tobacco was listed, along with drunkenness, gambling, cards, dancing and theater-going, in J.M. Judy's Questionable Amusements and Worthy Substitutes, which was published in 1904 by the Western Methodist Book Concern of Chicago. Judy wrote that "Tobacco dulls the mind. It does this not only by wasting the body, the physical basis of the mind, but it does it through habits of intellectual idleness, which the user of tobacco naturally forms. Whoever heard of a first-class loafer who did not eat the weed or burn it, or both?" In addition, he claimed, "Tobacco wastes the body" and "blunts the moral nature." But there was also the more direct concern that the poor would waste what little money they had on tobacco, instead of supporting their families, similar to a concern about alcohol in this era.

The Jewish leader Rabbi Yisrael Meir Kagan (1838-1933) was one of the first Jewish authorities to speak out on smoking. He considered it a waste of time and saw the practice of people "borrowing" (pilfering) cigarettes from each other as morally questionable.

Most modern opposition to smoking, however, is based on health concerns rather than moral judgments. Some public interest groups, usually described as "anti-smokers", are interested in controlling smoking as a political agenda; many consist of former "reformed" smokers.

Passive smoking

Passive smoking (also known as environmental tobacco smoke (ETS), involuntary smoking or secondhand smoke) occurs when the exhaled and ambient smoke from one person's cigarette is inhaled by other people. Non-smokers exposed to secondhand smoke are at greater risk for many of the health problems associated with direct smoking. In 1992, the Journal of the American Medical Association published a review of the evidence available from epidemiological and other studies regarding the relationship between secondhand smoke and heart disease and estimated that passive smoking was responsible for 35,000 to 40,000 deaths per year in the United States in the early 1980s. [5] (http://jama.ama-assn.org/cgi/content/abstract/267/1/94) Non-smokers living with smokers have about a 25 per cent increase in risk of death from heart attack and are also more likely to suffer a stroke, and some research suggests that risks to nonsmokers may be even greater than this estimate. One recent study in the British Medical Journal found that exposure to secondhand smoke increases the risk of heart disease among non-smokers by as much as 60 percent. [6] (http://bmj.bmjjournals.com/cgi/reprint/bmj.38146.427188.55v1) Passive smoking is especially risky for children and babies and can cause low birth weight babies, sudden infant death syndrome (SIDS), bronchitis and pneumonia, and middle ear infections. [7]  (http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Smoking_and_heart_disease_the_facts?OpenDocument)

Some controversy has attended efforts to estimate the specific risk of lung cancer related to passive smoking. The US Environmental Protection Agency (EPA) in 1993 issued a report estimating that 3,000 lung cancer related deaths in the US were caused by passive smoking every year. Tobacco industry lobbyists, such as the Alexis de Tocqueville Institution, and industry-funded researchers, such as S. Fred Singer, aggressively attacked the EPA study as "junk science". In 2002, a group of 29 experts from 12 countries convened by the Monographs Programme of the International Agency for Research on Cancer (IARC) of the World Health Organization reviewed all significant published evidence related to tobacco smoking and cancer. It concluded its evaluation of the carcinogenic risks associated with involuntary smoking, with second-hand smoke also being classified as carcinogenic to humans.[8] (http://monographs.iarc.fr/htdocs/monographs/vol83/02-involuntary.html) An earlier WHO epidemiology study also found "weak evidence of a dose-response relationship between risk of lung cancer and exposure to spousal and workplace ETS".[9] (http://jncicancerspectrum.oupjournals.org/cgi/content/abstract/jnci;90/19/1440) The fact that the evidence was described as "weak" has been interpreted by the tobacco industry and its supporters as evidence that the ETS-lung cancer link has been "disproven". More precisely, the "weakness" of the evidence stems from the fact that the risk of ETS for individuals is small relative to the very high risk of actually smoking, making it more difficult to quantify through epidemiology. In addition to epidemiology, moreover, several other types of scientific evidence (including animal experiments, chemical constituent analysis of ETS, and human metabolic studies) support the WHO and EPA conclusions.

Most experts believe that moderate, occasional exposure to secondhand smoke presents a low cancer risk to nonsmokers, but the risk is more likely to be significant if non-smokers work in an environment where cigarette smoke is prevalent. For this reason, many countries (such as Ireland) and jurisdictions (like New York State) now prohibit smoking in public buildings. Many office buildings contain specially ventilated smoking areas; some are required by law to provide them.

Legal issues

In many countries (including the United States, New Zealand, Canada, and Australia), it is illegal to sell tobacco products to minors. In Britain it is illegal to sell tobacco products to people under the age of 16; in 47 of the 50 United States the minimum age is 18 (Alabama, Alaska, and Utah raised the age to 19). Some countries have also legislated against giving tobacco products to (i.e. buying for) minors, and even against minors engaging in the act of smoking. Underlying such laws is the belief that only adults can make an informed decision regarding the risks of tobacco use.

Several Western countries have also put restrictions on cigarette advertising. In the United States, all television advertising of tobacco products is prohibited since 1971. In Australia, the Tobacco Advertising Prohibition Act 1992 (http://www.austlii.edu.au/au/legis/cth/consol_act/tapa1992314/index.html) prohibits tobacco advertising in any form, with a very small number of exceptions (some international sporting events are excepted, but these exceptions will be revoked in 2006). Other countries have legislated particularly against advertising that appears to target minors.

Some countries also impose legal requirements on the packaging of tobacco products. For example in the countries of the European Union and Australia, cigarette packs must be prominently labeled with one of various statements such as "SMOKING KILLS" and "SMOKING IS ADDICTIVE", accompanied by an explanation of the statement. See Australian tobacco labeling regulations (http://www.austlii.edu.au/au/legis/cth/consol_reg/tppisr714/). Canada has also imposed labels upon cigarette packs warning smokers of the effects. These labels say things such as: Cigarettes Hurt Babies, Tobacco Kills, etc. Cards are also inserted into cigarette packs in Canada. There are sixteen of them, and only one comes in a pack. They explain different methods of quitting smoking.

In addition, some jurisdictions impose restrictions on where smoking is allowed. According to the American Nonsmokers' Rights Foundation (http://www.no-smoke.org/), as of April 2004, the US states of Delaware, New York, Florida, California, Connecticut, Maine, and Utah prohibit smoking in restaurants. Delaware, New York, California, Connecticut, and Maine also prohibit smoking in bars. Similar restrictions have been proposed (though not yet implemented) for states such as Oregon, New Jersey, Minnesota, Illinois, Maryland, and Colorado.

From March 29, 2004, it became illegal in the Republic of Ireland to smoke in most enclosed places of work. This included all bars and restaurants. Similar legislation came into force in Norway on June 1, 2004, New Zealand on December 10, 2004 and will take effect in Scotland from 2006. In 2004, Bhutan became the first country in the world to ban smoking and the selling of Tobacco.

Beginning February 28, 2005, an international treaty, the WHO Framework Convention on Tobacco Control, will take effect. The FCTC is the world's first public health treaty. Countries that sign on as parties agree to a set of common goals, minimum standards for tobacco control policy, and to cooperate in dealing with cross-border challenges such as cigarette smuggling.

Recently some activists and officials have begun calling for a total ban on tobacco product sales and consumption altogether. see: smoking ban for more information.

Further reading

On the history of tobacco smoking

• Iain Gately: La Diva Nicotina. The Story of How Tobacco Seduced the World (2001) (ISBN 0743208129).

External links

Prevention & Self help

• Smoking Prevention Strategies for Urban and Minority Youth (http://www.ericdigests.org/1998-1/smoking.htm)
• Public use self help for smokers trying to quit (http://www.quit4good.com)

Statistics & Studies

• Scientific Facts on Tobacco Smoking (http://www.greenfacts.org/tobacco/index.htm) — A summary by GreenFacts of the report published by the International Agency for Research on Cancer (IARC).
• Smoking linked to yet more cancers (http://www.smh.com.au/news/Health/Smoking-linked-to-yet-more-cancers/2005/02/11/1108061872878.html) — An article on the longest-running study of rectal cancer, published in the British Journal of Cancer in February 2005, which adds a form of bowel cancer to the list of malignancies probably caused or exacerbated by smoking.
• Total adult smokers by country (http://www.nationmaster.com/graph-T/hea_tob_tot_adu_smo)

Notes

1. Note 1: "Nicotine: A Powerful Addiction." Centers of Disease Control and Prevention. [10] (http://www.cdc.gov/tobacco/quit/canquit.htm)
2. Joint Committee on Smoking and Health. Smoking and health: physician responsibility; a statement of the Joint Committee on Smoking and Health. Chest 1995; 198:201- 208
3. Boffetta, P., Agudo, A., Ahrens, W., Benhamou, E., Benhamou, S., Darby, S.C., Ferro, G., Fortes, C., Gonzalez, C.A., Jockel, K.H., Krauss, M., Kreienbrock, L., Kreuzer, M., Mendes, A., Merletti, F., Nyberg, F., Pershagen, G., Pohlabeln, H., Riboli, E., Schmid, G., Simonato, L., Tredaniel, J., Whitley, E., Wichmann, H.E., Saracci, R. 1998. Multicenter case-control study of exposure to environmental tobacco smoke and lung cancer in Europe. J. Natl. Cancer Inst. 90:1440-1450.
4. Osvaldo P. Almeida, Gary K. Hulse, David Lawrence and Leon Flicker, "Smoking as a risk factor for Alzheimer's disease (http://www.blackwell-synergy.com/links/doi/10.1046/j.1360-0443.2002.00016.x/full/): contrasting evidence from a systematic review of case-control and cohort studies," Addiction, Volume 97, Issue 1, Page 15 - January 2002.