Tobacco harm reduction (THR) is a public health strategy to lower the health risks to individuals and wider society associated with using tobacco products. It is an example of the concept of harm reduction, a strategy for dealing with the use of drugs. Tobacco smoking is widely acknowledged as a leading cause of illness and death,^[1] and reducing smoking is vital to public health.^{[2][3][4][5][6]}

Tobacco use if not stopped can be the cause of death in 50% of its users according to WHO report. ^[7] The benefits of tobacco cessation starts within minutes as heart rate and blood pressure starts falling.

The consumption of tobacco products and its harmful effects affect both smokers and non-smokers,^[8] and is a major risk factor for six of the eight leading causes of deaths in the world, including respiratory diseases, cardiovascular diseases, cerebrovascular diseases, periodontal diseases, teeth decay and loss, over 20 different types or subtypes of cancers, strokes, several debilitating health conditions, and malignant diseases.^{[2][3][4][5][6][9][10]} In high income countries, smoking rates have been reduced mostly by reducing the uptake of smoking among younger people rather than improving the rates of quitting among established smokers. It is, however, mostly current smokers who will face disease and death from smoking.^[11][12]

Nicotine itself, however, is addictive but not otherwise very harmful, as shown by the long history of people safely using nicotine replacement therapy products (e.g., nicotine gum, nicotine patch).^[13] Nicotine increases heart rate and blood pressure and has a range of local irritant effects but does not cause cancer.^[14] None of the three main causes of death from smoking—lung cancer, chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), and cardiovascular diseases—is caused primarily by nicotine; the main reason smoking is deadly is the toxic mix of chemicals in smoke from combustion (burning) of tobacco. Products that can effectively and acceptably deliver nicotine without smoke have the potential to be less harmful than smoked tobacco. THR measures have been focused on reducing or eliminating the use of combustible tobacco by switching to other nicotine products, including:

1. Cutting down (either long-term or before quitting smoking)
2. Temporary abstinence
3. Switching to non-tobacco nicotine containing products, such as pharmaceutical nicotine replacement therapies or currently (generally) unlicensed products such as electronic cigarettes
4. Switching to smokeless tobacco products such as Swedish snus
5. Switching to non-combustible tobacco products

Quitting all tobacco products definitively reduces risk the most. However, quitting is difficult, and even approved smoking cessation methods have a low success rate.^[1] In addition, some smokers may be unable or unwilling to achieve abstinence.^[15] Harm reduction is likely of substantial benefit to these smokers and public health.^[1][13] Providing reduced-harm alternatives to smokers is likely to result in lower total population risk than pursuing abstinence-only policies.^[16]

The strategy is controversial: supporters of tobacco harm reduction assert that lessening the health risk for the individual user is worthwhile and manifests over the population in fewer tobacco-related illnesses and deaths.^[15][17] Opponents have argued that some aspects of harm reduction interfere with cessation and abstinence and might increase initiation.^[18][19] However, surveys carried from 2013 to 2015 in the UK^[20] and France ^[21] suggest that on the contrary, the availability of safer alternatives to smoking is associated with decreased smoking prevalence and increased smoking cessation. In Japan the sales of cigarettes have decreased by 32% since the introduction of heated tobacco products.^[22]

The concept of tobacco harm reduction dates back to at least 1976 when Professor Michael Russell wrote: "People smoke for nicotine but they die from the tar"^[23] and suggested that the ratio of tar to nicotine could be the key to safer smoking.^[13][15] Since then, the harm from smoking has been well-established as being caused almost exclusively by toxins released through the combustion of tobacco.^[1] In contrast, non-combustible tobacco products as well as pure nicotine products are considerably less harmful, although they still have the potential for addiction.^[13]

Debates on tobacco harm reduction tend to be geographically defined arguments, because of the varying legal, moral, and historical status of tobacco, and the different types of tobacco products and use in different cultures around the world. For instance, cigarette smoking is the dominant form in the United States, while use of cigars, pipes, and smokeless tobacco is limited to a much smaller population. Anti-smoking advocacy efforts and widespread popularization of the negative health effects of smoking over the last few decades have led to restrictions in the sale and use of tobacco products. Despite this, tobacco in all its forms has remained a legal product in most societies. A notable exception is the European Union, where the most dangerous products (cigarettes) are available but smokeless tobacco products, which are far less hazardous, are banned.^[24] The exception is Sweden, where there is a long tradition of smokeless tobacco (snus) use among men.

In October 2008 the American Association of Public Health Physicians (AAPHP) became the first medical organization in the U.S. to officially endorse tobacco harm reduction as a viable strategy to reduce the death toll related to cigarette smoking.^[25][26][27]

Cigarette manufacturers have attempted to design safer cigarettes for almost 50 years, but results have been marginal at best.^[28] Filters were introduced in the early 1950s, and manufacturers were selling low-yield cigarettes by the late 1960s.^[28] Initially it was thought that these innovations were harm reducing.^[29] For example, in 1976 investigators at the American Cancer Society published research concluding that light cigarettes were safer.^[30] The study authors wrote that "total death rates, death rates from coronary heart disease, and death rates from lung cancer were somewhat lower for those who smoked 'low' tar-nicotine cigarettes than for those who smoked 'high' tar-nicotine cigarettes." However, scientific evidence suggests that switching from regular to light or low-tar cigarettes does not reduce the health risks of smoking or lower the smoker's exposure to the nicotine, tar, and carcinogens present in cigarette smoke.^[31] Indeed, the WHO recommends that misleading terms, including 'light' and 'mild', should be removed from tobacco product advertising, packaging, and labeling.^[32][33]

It has been established that use of Swedish and American smokeless tobacco confers only 0.1% to 10% of the risks of smoking,^[15] though smokeless products in India and elsewhere in Asia contain higher levels of contaminants and thus confer greater risks.^[17] Two respected medical groups believe that smokeless tobacco may play a role in reducing smoking-attributable deaths. In 2007, Britain's Royal College of Physicians concluded "...that smokers smoke predominantly for nicotine, that nicotine itself is not especially hazardous, and that if nicotine could be provided in a form that is acceptable and effective as a cigarette substitute, millions of lives could be saved."^[34]

In the United States, a study based on National Health Interview Survey data found that 73% of smokers who switched to smokeless tobacco as part of their latest quit attempt were successful in quitting smoking.^[35] In the same study, smokers who used pharmaceutical nicotine products in their most recent quit attempt had success rates between 0 and 35%.^[35]

E-cigarettes are battery-powered devices that provide nicotine for inhalation in a vapour generated by heating a solution of water, nicotine propylene glycol or vegetable glycerin and typically some flavouring. They were first developed in China in 2003, and first introduced to Europe and the US around 2006.^[40]

It is unclear whether using heat-not-burn tobacco products instead of traditional cigarettes has a substantial effect on the risk of harm.^[50]

Smokers remain confused about tobacco harm reduction. In a 2004 survey, about 80-100% of participants incorrectly perceived low-yield cigarettes as harm-reducing, while 75-80% mistakenly believed that switching to smokeless tobacco conferred no risk reduction.^[51]

Similar confusion exists about electronic cigarettes. In the UK, research commissioned by the anti-smoking charity Action on Smoking and Health found that in 2016, more than three times as many people think e-cigarettes are as harmful or more harmful than smoking than in 2013 (25% vs 7%), the highest proportion since the survey began.^[49] They expressed concern that the proportion of adult smokers who thought that e-cigarettes were more or equally harmful than cigarettes was highest in those who had never tried e-cigarettes, and these perceived potential harms was the main reason why they had not tried them.^[49]

In 2015 a report commissioned by Public Health England noted, as well as the UK figures above, that in the US belief among responders to a survey that vaping was safer than smoking cigarettes fell from 82% in 2010 to 51% in 2014.^[52] The report blamed "misinterpreted research findings", attracting negative media coverage, for the growth in the "inaccurate" belief that e-cigarettes were less harmful than smoking, and concluded that "There is a need to publicise the current best estimate that using EC is around 95% safer than smoking".^[53]

In an article published by the Wall Street Journal in 2016 entitled "Are E-Cigarettes a Healthy Way to Quit Smoking?", Dr. Jed E. Rose co-inventor of the nicotine patch said, "Having worked my entire career to develop effective smoking-cessation treatments, I have realized that current approaches are ineffective for the vast majority of smokers. Alternative approaches are urgently needed. The World Health Organization predicts^[54] a billion deaths will be attributable to smoking during the 21st century. Electronic cigarettes have an unparalleled potential to reduce the public-health impact of smoking, by allowing smokers to replace the habit and nicotine of smoking without the toxic effects of combustion."^[55]

Whilst tobacco harm reduction approaches have the potential to reduce risks to the current adult smoking population, there are hypothesised potential hazards to wider public health. Smoking has become less acceptable over recent years in a number of countries, a result of a number of the Framework Convention on Tobacco Control (FCTC) guidelines to reduce smoking prevalence. The renormalisation of smoking is a concern if e-cigarette use appears to become more appealing, for example through their use in locations where conventional cigarettes are prohibited, advertising and increased e-cigarette use by parents, siblings, peers, celebrities or other influential groups.^[56][57]

Concerns have also been raised that non-tobacco nicotine use may results in uptake of tobacco smoking that would not otherwise have occurred. This 'gateway theory' has been largely applied to the use of e-cigarettes by non-smokers and particularly children.^[58] There is no reported evidence, however, that NRT use among young people has ever acted as a gateway to smoking, or that e-cigarette use has resulted in any appreciable increase initiation of smoking among children or adults. The Royal College of Physicians suggest that any association between e-cigarette and conventional cigarette use is likely due to common liability to use these products and the use of e-cigarettes to reduce smoking.^[34]

Dual use of tobacco products and non-tobacco nicotine by continuing smokers is another aspect which has raised concern. It is suggested that dual use could inadvertently sustain smoking by making it easier for smokers to temporarily abstain from tobacco use, or encourage smokers to move towards dual use rather than complete cessation in the mistaken belief that this offers significant health gains. Dual use of tobacco and NRT is licensed by the Medicines and Healthcare products Regulatory Authority (MHRA) as a tobacco harm reduction strategy which actually increases the chance of quitting.^[59] The Royal College of Physicians reviewed evidence around dual use and smoking cessation and reported that findings were suggestive that e-cigarettes had the potential to offer the same cessation gains,^[34] although further research would be helpful to more clearly delineate such an effect.

Much of the opposition to tobacco harm reduction has come from organisations funded by the US Bloomberg Philanthropies including Vital Strategies, the Campaign for Tobacco Free Kids and the UK University of Bath Tobacco Control Group and it is claimed that the USA is the epicentre for all anti tobacco harm reduction globally.^[22]

• History of commercial tobacco in the United States
• List of additives in cigarettes
• List of cigarette smoke carcinogens

• "Nicotine without smoke: Tobacco harm reduction". RCP London. 28 April 2016.
• De Andrade M, Hastings G (May 2013). "Tobacco Harm Reduction and Nicotine Containing Products: Research Priorities and Policy Directions". University of Stirling. hdl:1893/13224.

• Global Tobacco Control - CDC