Karl Lund | 24 September 2013
The extent and nature of the impact on public health of making snus available in new markets will depend on the relative risk of snus and smoking, and the relative uptake and use by smokers and non-smokers. Given a medical consensus that snus is approximately 90-99% less harmful than smoking, the overall effect from snus on public health will come down to the balance between its beneficial effect on smoking prevalence and its adverse effects on overall prevalence of tobacco use.
Norway and Sweden, with its long tradition of snus use, constitutes a natural laboratory in which we can study how snus competes for market share with cigarettes. The much debated ban on snus in the rest of the European Union leaves these countries as the only in Europe where we have the possibility to observe transitions between cigarettes and snus. Below, I have summed up some findings from studies concerned with the pattern of snus use in Scandinavia.
Reduction in overall tobacco consumption
The new type of low-toxic, low-nitrosamine snus, was introduced to the Norwegian nicotine market during the 1990’s. In 1985, less than 5% of the tobacco was consumed as snus, but today snus make up one third of the market. The increased market share for snus has occurred without increasing the overall consumption of tobacco. Since 1985 the per capita consumption of tobacco in Norway has been reduced by 20% - even if we include border trade, smuggling, tax free etc. The overall percentage of male tobacco users decreased from 55% to 37% in this period, while the reduction among women was from 45% to 30%.
Snus users are mainly recruited from the segment of smokers
If snus users primarily were recruited from the segment of non-smokers, then snus – not being totally risk-free – would put an extra burden on a population that would have been better off without snus use. But in Norway approximately 40-45% of the snus users are former smokers, and an additional 30% are smokers who, for the most part, use snus to quit smoking or to cut down on their consumption. Still a quarter of the snus users are recruited from the segment of non-smokers. However, data suggests that many of these primary snus users would otherwise have started to smoke cigarettes if snus had not been available to them. There is ample evidence that i) smokers, ii) former smokers, and iii) youth who have characteristics that predispose to smoking, makes up the great majority of the present snus users. Even if availability to snus may lead to use among people who would not otherwise have used a tobacco product, any public health impact from this is likely to have been more than offset by the substantial numbers who chose snus instead of cigarettes.
Snus is most popular method to quit smoking
Among smokers who apply a specific method to quit, snus is most common followed by nicotine chewing gum, self-help materials and nicotine patches. This has been the case among male smokers for decades, but recent observations indicates that snus has displaced pharmaceutical nicotine as a cessation tool also among female smokers.
Snus attracts quitters who refrain from traditional methods
Users of medicinal nicotine products had a greater tendency to use additional methods for quitting smoking, while use of snus seemed to be a more solitary method, and might appear convenient for smokers who for some reason do not want to make use of the NRTs. This might be important because the remaining group of smokers increasingly contains a higher proportion of people with social, mental and demographic characteristics associated with reduced ability to stop smoking with traditional methods.
The effectiveness of snus in smoking cessation
Several observational studies have shown that the quit ratio for smoking is higher for smokers who use, or have used snus, than for smokers who have never used snus. This is also observed in randomized controlled trials. Moreover, a consistent finding is that snus users are more likely to have quit smoking completely or considerably reduced their cigarette smoking, than users of medicinal smoking cessation products. The enhanced effect from snus over medicinal nicotine products (efficacy) combined with the high likeability of snus as a smoking cessation method implies that the impact on smoking abstinence at the population level (effectiveness) is much higher from snus.
The magnitude of dual use is small
There is a concern that availability to snus might result in dual use and therefore jeopardize the potential role of snus in a tobacco harm reduction perspective. Data from a time-series covering the period 1985-2010, a period in which the market share of snus increased from 5% to above 30%, the segment of male dual users of cigarettes and snus varied in a narrow range between 4%-7% for the whole period. The great majority of dual users had started with cigarettes, while typically below 25% report snus to be their first tobacco product.
Smokers’ motives for additional snus use
A majority of dual users with a daily intake of snus report that the purpose of their snus use is to quit smoking. However, harm reduction issues such as smoking reduction and smoking substitution are also important motives for additional snus use. Only 25% of the Norwegian dual users state that neither smoking cessation nor smoking reduction is the reasons to their snus use.
Reduced smoking intensity among dual users
Dual users of cigarettes and snus smoke fewer cigarettes, on average, than do exclusive smokers. There is also data showing that unsuccessful attempts at using snus to quit smoking are likely to result in reduced smoking intensity. Consistent with these findings, exclusive cigarette smokers in Norway reported a weekly cigarette consumption that was 40% above that of dual users of snus and cigarettes among men.
Does dual use delay smoking cessation?
Snus may have the potential to reduce exposure to tobacco toxins, but snus may also have the unfavourable potential to delay cessation. In Norway no such difference in intention to quit smoking (within in 6 months) was observed between dual users of snus and cigarettes and exclusive smokers. On the contrary, expectancies of being smoke-free five years into the future were significantly more prevalent among dual users than exclusive smokers.
Dual use – a transient phenomenon?
Even if the fraction of dual users of snus and cigarettes is small in the total male population in Norway, approximately 10% of daily snus users and 40% of occasional snus users smoke cigarettes on a regular basis. There is some evidence that this relationship is caused by a certain trajectory-of-tobacco-use among dual users; many occasional snus users are at the time of the survey caught in an incomplete transition phase of stopping smoking daily, and will replace cigarettes with daily use of snus later. However, there is also some data from Sweden that dual use is not entirely a transient phenomenon; many ‘some day’ users of snus use both products interchangeably without trending toward either product.
No support for the gateway hypothesis
The Swedish data, with its prospective and longtime follow-up do not lend much support to the theory that snus is a gateway to future smoking. In line with this, a Norwegian prospective study found that snus enabled few of the cognitions which usually increase the desire to smoke among young people. Moreover, at the aggregate level, the correlation between snus use and smoking is negative in the sense that the proportion of young snus users have increased, while the proportion of young smokers have declined. If a strong gateway effect really existed, we should rather expect to find that the increase in snus use was associated with a subsequent increase in the percentage of smokers - and not a reduction.
The experience from Norway and Sweden suggest that low-nitrosamine snus has the potential to gain market share on behalf of cigarettes. Increased snus use has not increased overall tobacco consumption but on the contrary helped to reduce smoking. This has happened through two mechanisms; i) snus attract tobacco-prone youth who otherwise would have started to smoke, ii) snus increases quit rates for smoking – functioning as a suitable exit for smokers who for some reasons don’t want to make use of or fail to quit with traditional methods for quitting smoking. Finally, the availability to snus has not increased the proportion of dual users but helped to reduce their smoking intensity. This pattern of use has occurred in Sweden, and is currently being replicated in Norway. I can’t think of any reason why this should not take place in any other European country.