Commentary on Lund et al. (2011): Consolidating the evidence on effectiveness of snus for smoking cessation – implications for public health

Authors


Reduction of tobacco-related deaths is an urgent goal in public health. For the first half of this century most of these deaths will occur among existing smokers [1]. Therefore, prevention of onset of smoking will not have a major impact until later, while quitting smoking can quite rapidly yield substantial reduction of smokers' health risks. Consequently, it is important to ascertain what means are available that can effectively help as many smokers as possible to quit.

There is good evidence on the effectiveness of various therapies with behavioural and/or pharmacological components offered by qualified therapists, but the vast majority of all quit attempts are made without professional assistance [2]. Some unassisted quitters do not use any kind of aid at all, while others make use of various products to alleviate the craving for cigarettes. From a public health perspective it is important that as many smokers as possible can find cessation aids that are effective and acceptable to use. In this context there has been a good deal of discussion regarding the effectiveness of snus, the Swedish type of low-toxicity smokeless tobacco. In Sweden this product has been used extensively for smoking cessation and a high degree of effectiveness has been demonstrated, both for men and women [3–5].

Current issues. The paper by Lund et al. [6] provides a timely contribution to the discussion about snus for smoking cessation. It confirms earlier Swedish research data as such and, together with another recent paper by the same lead author, it also widens the perspective by demonstrating that the same patterns can actually develop in a country where snus has not such an old tradition as in Sweden [7]. This is particularly important, as some authors have tended to devalue the importance of the Swedish experience by claiming that it could not be replicable anywhere outside Sweden [8]. There are even authors who make explicit claims that evidence on the effectiveness of snus for smoking cessation does not exist [9]. Questions have been raised about the continued intake of nicotine when quitting smoking by switching to snus. The daily dose of nicotine is similar for average snus users as for average smokers. However, as the delivery speed is slower in snus use, the strength of nicotine dependence could be assumed to decrease [10]. Indeed, a substantial number of switchers eventually quit snus use as well and become tobacco- and nicotine-free [3,4].

There have also been concerns that uptake of snus use might become an additional tobacco use rather than a replacement and thereby fail to incur smoking reduction, but there is a good deal of evidence to the contrary. For example, the current Norwegian study has demonstrated that, just as in Sweden, the prevalence of dual daily use is very low.

Quitting smoking by taking up snus use can result either in quitting all tobacco use or in moving from high-risk to low-risk tobacco use. Even in the latter case, the risk reduction is so large that the benefit cannot be offset by any reasonably conceivable reduction of the rate of quitting all tobacco use. This is illustrated by a study suggesting that, for example, male 40-year-old smokers who switch to snus will be expected to save 4.3 years of life that would have been lost by continued smoking, almost as much as 4.5 years if quitting all tobacco use [11].

Future research. Few clinical trials have been carried out to assess the use of snus for smoking cessation. Such studies can establish measures of efficacy under controlled conditions, but most quit attempts are made in ‘real life’ outside clinical settings. The above Norwegian and Swedish epidemiological studies have yielded assessments of effectiveness at population level. From a public health perspective this is more important. It now seems that the current body of evidence justifies the conclusion that snus use should be recognized as an effective method for large-scale smoking cessation. This conclusion has already been supported in reports from various authoritative bodies [12–14]. In the interests of public health, the most needed type of future research would be prospective studies of nation-wide representative cohorts where occurrence, procedure and outcome of quit attempts are followed over a period of several years.

Studies from Sweden and the United States have demonstrated that misbeliefs regarding snus and other nicotine products are very common [15,16]. This is likely to discourage many smokers from adopting effective cessation practices with use of nicotine-containing aids in ‘real-life’ attempts to quit smoking. The current Norwegian study consolidates the evidence on the effectiveness of snus for smoking cessation. This should encourage the use of effective smoking cessation methods to the benefit of public health.

Declaration of interests

None.

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