There are many different forms of smokeless tobacco, including chewing tobacco, oral snuff and nasal snuff. Non-traditional forms include compressed tobacco lozenges and dissolvable strips. The health risks associated with smokeless tobacco products vary considerably between types of products and within the same class of product.1, 2 The smokeless tobacco products that are most relevant to the harm reduction debate are those that have been produced to be relatively low in toxins, such as carcinogenic nitrosamines.1–5
Sweden has a similar prevalence of tobacco use to its neighbours, but one of the world's lowest tobacco-attributable mortality rates. Some observers have suggested this phenomenon, known as 'the Swedish experience' is explained by the increasing use of smokeless tobacco, a trend that has corresponded with a decline in smoking prevalence, particularly among Swedish men who are the greatest users of smokeless tobacco.6–8 However, this interpretation has been debated.9
The most common form of smokeless tobacco used in Sweden is a moist oral snuff called snus, which is available either as loose tobacco or pre-packaged portions that resemble teabags. Unlike other smokeless tobacco products marketed in the US and other countries, snus is pasteurised rather than fermented and stored under refrigeration to minimise bacterial growth. These processes greatly reduce the formation of nitrosamines, the main carcinogens in tobacco. This, and the absence of the combustion products associated with smoking (e.g. carbon monoxide, small particulate matter) reduces the risks of cardiovascular disease, chronic obstructive pulmonary disease and cancer compared to smoking. Unlike cigarettes, snus does not produce secondhand smoke or carry a risk of causing accidental fires.
Long-term prospective cohort studies have observed a lower risk of many tobacco-related diseases and overall lower mortality in snus users compared to smokers.8,10–13 Snus use appears to carry some residual risks, albeit lower than for smoking, of pancreatic cancer,11,14,15 cardiovascular disease16,17 and possibly diabetes18,19 compared with no tobacco use. Snus use is also associated with dental disease and gum lesions, called leukoplakia, but these appear to disappear on discontinuation of use.20
In Sweden, among people who have ever smoked regularly, those who use snus are more likely to have quit smoking than those who do not.7,21,22 A similar relationship is also seen in Norway among currently daily and former snus users.23 The Swedish experience has prompted some researchers to suggest that smokers who are unable to quit should use low nitrosamine smokeless tobacco products, such as snus, to reduce tobacco-related harm.24 This proposal is contentious.25–27
Some health professionals do not feel that the existing epidemiological studies showing a lower risk of tobacco-related disease in snus users are sufficient to support snus use as a harm reduction stragey. Others are concerned that the difference in potential harm between snus and smoking has not have been fully described in existing studies. Some believe that any health risk from snus, no matter how small, is too great for its use to be encouraged. However, the difference in healthy life expectancy and overall mortality risk between smokers who quit all tobacco and smokers who switch to low nitrosamine smokeless forms appears to be small.28,29 Sweden has also achieved substantial reductions in tobacco-attributable mortality despite a high prevalence of snus use among men.
Snus has had an extensive traditional use in Sweden, where it was known as 'the poor man's luxury'. Whether the Swedish experience would transfer to Australia, which has never had a significant smokeless tobacco tradition, is uncertain. A growing smokeless tobacco market in Australia during the 1980s was halted by the introduction of a commercial sales ban in 1991, but it is unknown whether these products would have become widespread without the ban.30 A survey of Australian smokers in 2008 found that around half were interested in purchasing low-nitrosamine varieties of smokeless tobacco.31 However, the survey participants were only provided with pictures and written descriptions of the products rather than samples to try, and most had no previous experience of using smokeless tobacco. In contrast only 13% of smokers in a Californian survey stated they would probably or definitely switch to smokeless tobacco if they thought it was less harmful than smoking.32
There are also behavioural aspects of smoking that may not be adequately replaced by snus use. For example, smoking offers something to do with the hands and is easy to do while engaging in other social activities such as drinking and talking. Snus is simply placed under the top lip and left there until it is removed. Talking and drinking while using snus requires more skill than smoking to keep the tobacco portion in place. The small bulge visible in the upper lip during snus use may also lack the supposed glamour of smoking.
Low nitrosamine smokeless tobacco products are not harmless and can be as addictive as smoking.33 Many health professionals feel it is unethical to promote the use of a substance that offers no direct benefit to the user (the indirect benefit is the absence of smoking), is addictive and still carries risks. Proponents of tobacco harm reduction with smokeless tobacco counter that it is unethical to deny smokers access to products with substantially lower risks than smoking and to deny them accurate information about the benefits of switching to them, particularly as cigarettes, the most harmful tobacco product, are readily available.34
Opponents argue that quitting all tobacco use is the only health advice that doesn't carry any risk. Proponents argue that many smokers fail to follow this advice and that 'quit' or 'keep smoking', sometimes described as 'quit or die', should not be the only options available.35 While it is debatable whether health professionals should recommend low nitrosamine smokeless tobacco products to smokers, it is arguably unethical to provide inaccurate information about the relative harms of these products and cigarettes due to the mistrust such misinformation can create.36, 37
The lower harmfulness of low nitrosamine smokeless tobacco compared with cigarettes is likely to be an important motivator for smokers to switch products. For example, in a survey of Australian smokeless tobacco users, just over half stated they used smokeless tobacco because it was less harmful than smoking 30 and users of non-cigarette tobacco products are more likely to believe they are less harmful than cigarettes than non-users.38–40 Surveys of smokers in Australia, Canada, the UK and the US suggest that few smokers believe that smokeless tobacco is less harmful than cigarettes.38,41 Misperceptions about the relative harmfulness of smokeless tobacco products compared with cigarettes could be an important barrier to smokers switching to these less-harmful products. The challenge is avoiding messages that products like snus are 'less harmful' being misinterpreted as meaning that they are 'harmless'.
Using low nitrosamine smokeless tobacco products may reduce tobacco-related disease in individual smokers who make the switch, but widespread use could still result in population level harm in a number of ways. Firstly, if these products proved more popular among non-smokers than smokers, then overall harm could increase. Secondly, their promotion could keep current smokers smoking (instead of quitting) or lead some non-smokers to commence smoking. This is the most likely way in which smokeless tobacco promotion could produce population harm because the large difference in health risk between smoking and low nitrosamine smokeless tobacco use means that a very large number of non-smokers need to use these products to offset the health gain achieved from a smoker switching to them.25,42 In Sweden, snus use very rarely leads to smoking in non-smokers.7 It is unknown whether similar patterns of use would occur in Australia.
Tobacco manufacturers have argued that they should be able to market and promote reduced harm smokeless tobacco products in order to inform smokers of the benefits of switching. This is an important issue because if these products are to have a population level benefit, a sufficient number of smokers need to make the switch. However, promotion of smokeless tobacco via tobacco industry advertising may increase overall tobacco use, possibly including smoking among current non-smokers. Some cigarette manufacturers have also produced 'snus versions' of their most popular brands of cigarettes.43 How to allow these products to be promoted for tobacco harm reduction without allowing the promotion of the corresponding cigarette brand would be a challenge.
In countries where tobacco advertising is allowed, cigarette manufacturers have promoted dual use of smokeless and smoked tobacco products as a way to get around public smoking bans.44 Such 'dual use' could reduce or even negate any health benefit from snus use by deterring quitting. Public smoking bans not only protect non-smokers from environmental tobacco smoke, but have the added benefit of encouraging smokers to quit due to the inconvenience these bans produce. Some of these quitters may therefore be encouraged to keep smoking as they can get through the inconvenient times with a short-term alternative.45
In Norway, while current daily or former snus use is associated with quitting smoking, current occasional snus use is not.23 This may be evidence of a pattern of dual use that deters quitting smoking. Alternatively, these dual users may be in a process of gradually moving from one product to another or of quitting all tobacco use. In the US and Sweden, dual use of smoked and smokeless tobacco is uncommon and does not appear to be a stable pattern of tobacco use.46,47 Some harm reduction advocates have suggested that dual use is not necessarily a negative if it encourages smokers to try smokeless tobacco and leads to some switching completely. Whether this is a likely outcome remains to be seen. Clearly, addressing the need to inform inveterate smokers of the benefits of switching to low nitrosamine smokeless tobacco without deterring would-be quitters or encouraging smoking in non-smokers requires careful regulation of information to avoid these potential negative consequences.
Some tobacco control professionals view tobacco harm reduction with smokeless tobacco as a distraction from the main task of encouraging smokers to quit tobacco use and discouraging uptake.25 Tobacco smoking, they point out, has declined in Australia without these products. Supporters of harm reduction argue that it offers an additional strategy that may hasten the decline in smoking and may reach those smokers who have been resistant to traditional tobacco control strategies or have been unable to quit tobacco use despite repeated efforts.31,48
Nicotine replacement therapy (NRT) products, such as gum, lozenges or inhalers, have also been suggested as a long-term alternative to smoking. Because these present lower risk than smokeless tobacco, it has been argued that there is no need for smokeless tobacco products as a harm reduction alternative.
This argument ignores the possibility that smokeless tobacco may be more attractive to smokers than NRT. Smokeless tobacco is a purely recreational tobacco product that can deliver nicotine in similar amounts to the user as smoking. It may, therefore, be a better substitute for cigarettes for smokers who want to continue using tobacco recreationally. NRT is also primarily marketed as a medicine for short-term assistance during cessation. Currently available NRT products are low dose, which prevents them from providing a sufficient 'buzz' for smokers who want to use nicotine recreationally. Higher dose, recreational, 'clean' nicotine products face substantial regulatory barriers because of their addictiveness. Australia's drugs and poisons regulatory system also does not provide for nicotine to be sold for recreational use, unless it is contained within tobacco intended for smoking.49 Pharmaceutical companies, who manufacture NRT, are unlikely to see the marketing of a recreational, addictive product as their core business. Pharmaceutical companies may also be concerned that long-term use of high-dose nicotine products may carry a higher health risk than short-term use of low-dose NRT, which has been established as safe.
In Sweden and Norway, snus is a more popular smoking cessation aid than NRT gum or patches and smokers who use snus are more likely to quit than smokers who use NRT.7,22,50–52 Among the possible reasons for this greater popularity and higher success rate are the social acceptance of snus use in Sweden, its lower cost (before 2007, snus was taxed at a lower rate than cigarettes), the higher nicotine delivery from snus compared to NRT, and possibly longer use of snus after quitting compared with NRT. Using NRT to quit smoking may also be stigmatised by some smokers who see the use of a medication to quit as a sign of drug addiction. Snus, which is not a medication, may be seen as a 'smarter choice' rather than a sign of weakness. As uptake of NRT in Australia remains relatively low,53 a product that may be more attractive to smokers and more effective, even if marginally riskier, could increase the number of quitters and therefore produce a greater population level benefit.
Smokeless tobacco products appear to be less effective at reducing abstinence symptoms than cigarettes.54,55 However, some small-scale trials suggest that smokers may prefer moist oral snuff over NRT and that snuff reduces cigarette cravings more than NRT.56,57 There is also some evidence from population surveys that switching to smokeless tobacco may be more effective than using NRT.7,51,58 There is little evidence from clinical trials available. A small trial found that smokers who were given smokeless tobacco products reduced their cigarette intake and increased their interest in quitting smoking compared with those who were not given these products.59 A survey of Australian smokers assessed the potential impact of making low nitrosamine smokeless tobacco available at a lower cost than cigarettes by asking the smokers what they would do (continue smoking, quit or switch to smokeless tobacco) under different policy scenarios.31 The option of purchasing smokeless tobacco at a lower cost than cigarettes combined with a substantial price increase on cigarettes resulted in more smokers stating they would stop smoking than if the cigarette price increase was not combined with availability of smokeless tobacco. The option of switching to smokeless tobacco appeared most attractive to those who were resistant to quitting rather than those who indicated they would quit with just a price increase alone. These results suggest that a lower tax on smokeless tobacco compared with smoked tobacco could produce a greater reduction in the number of smokers than simply increasing cigarette taxes. Similarly, a Californian survey found that smokers with greater intentions of quitting were less likely to be interested in switching to smokeless tobacco, but smokers who were trying to cut down their cigarette intake and smokers who had made unsuccessful quit attempts were more likely to be interested in switching to smokeless tobacco.32 However, larger trials are needed to confirm these survey and pilot study results and to determine whether the option of using smokeless tobacco translates to fewer smokers without detrimental effects on quitting.
Current federal legislation prohibits the commercial sale of smokeless tobacco within Australia. Importation for personal use is permitted. This regulatory situation allows for current users and smokers to access smokeless tobacco products while deterring non-tobacco users (particularly youth) from commencing.60 Importers face delays between ordering and receiving their smokeless tobacco products due to shipping and variable processing times by the Australian Customs and Border Protection Service. They must also pay tobacco duty on their products before they can be collected. Restrictions on posting of tobacco products through the US Postal Service since 2010 have further reduced access.61 Compared with the convenience of purchasing cigarettes, these barriers mean that only highly motivated users are likely to import these products. Some researchers have suggested that for low nitrosamine smokeless tobacco to be a realistic harm reduction option for most Australian smokers, restricted domestic sales would need to be allowed to recommence.30,62
The epidemiological evidence and the Swedish experience suggest that low nitrosamine smokeless tobacco may be an important tobacco harm reduction opportunity.62 With uncertainty around its potential effect on other tobacco control policies, most Australian commentators have been cautious about such proposals.63
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