Health effects of snus

Divergent views on harm reduction

There is some debate among public health researchers over the use of "safer" tobacco or nicotine delivery systems, generally dividing along two lines of thought. Some (primarily in the European Union and Canada) believe in "tobacco harm reduction", with the general belief that while it should remain a goal to reduce addiction to nicotine in the population as a whole, the reduction of harm to the health of those who choose to use nicotine is more pragmatic than the desire to reduce overall nicotine addiction. In other words, people using more harmful forms of tobacco (e.g., cigarettes) should be encouraged to switch to less harmful products (e.g., snus). The other school of thought is that no tobacco product should be promoted, and that attention should be placed instead on getting users to switch to nicotine replacement therapy or quit altogether.

Snus as a harm reduction tool: proponents' perspective

One proponent of using snus for harm reduction is Karl Fagerström, who has a PhD in psychology and is researcher in smoking cessation in Sweden. Some research available today shows snus use reduces or eliminates the risk of cancers associated with the use of other tobacco products, such as chewing tobacco (the type primarily used in the US and Canada, created in a process similar to cigarette tobacco) and cigarettes.[24] The widespread use of snus by Swedish men (estimated at 30% of Swedish male ex-smokers), displacing tobacco smoking and other varieties of snuff, is thought to be responsible for the incidence of tobacco-related mortality in men being significantly lower in Sweden than any other European country. In contrast, since women traditionally are less likely to use snus, their rate of tobacco-related deaths in Sweden can be compared to that of other European countries.

Snus may be less harmful than other tobacco products (see above). According to Kenneth Warner, director of the University of Michigan Tobacco Research Network, "The Swedish government has studied this stuff to death and, to date, there is no compelling evidence that it has any adverse health consequences. … Whatever they eventually find out, it is dramatically less dangerous than smoking."[25]

Snus in the context of tobacco harm reduction

A 2014 report commissioned by Public Health England on another avenue for tobacco harm reduction, electronic cigarettes, examined the case of snus as "a unique natural experiment in the impact of a socially accepted, non-medical, affordable and easily accessible reduced harm product on the prevalence of tobacco smoking". They concluded that "Although controversial, the Swedish natural experiment demonstrates that despite dual use and primary uptake of the reduced-harm product by young people, availability of reduced-harm alternatives for tobacco smokers can have a beneficial effect. While snus is not likely to become a legal or indeed politically viable option in the UK, this data proves the concept that harm reduction strategies can contribute to significant reductions in smoking prevalence."[26]

Debates on snus use and life expectancy

Ongoing discussion and debates among primary scientific researchers of the effects of snus use on life expectancy appear to indicate a significant increase in life expectancy among persons who previously smoked tobacco and switch to snus, depending on the age of the persons who switch, even when it is assumed that 100% of the risk of cardiovascular diseases among smokers transfers to snus users. This study determined that "for net harm to occur, 14–25 ex-smokers would have to start using snus to offset the health gain from every smoker who switched to snus."[27] It is also noted, in the correspondence seen in the previous citation,[28][29] that concerns about the effect of marketing by the tobacco industry, as influenced by the results of these scientific studies, is of primary concern to many researchers in the field, including the risk of emboldening the industry to attempt to increase snus sales among young people and promote dual-use of snus and smoked tobacco, and the use of medical nicotine, rather than snus, can better target at-risk populations, given better access and pricing.

Limitations of nicotine replacement therapy and the potential role of snus

However, a growing consensus among researchers of smoking cessation have found nicotine replacement therapy (NRT) products to have limited effectiveness because tobacco users may be seeking the combination of MAO inhibitors (which are found in tobacco) and nicotine, or that NRT products do not deliver sufficient quantities of nicotine. MAO inhibitors in tobacco act to amplify the rewarding effects of nicotine, but may also act as a form of self-medication for people with depression. This could explain the association between mental illness and smoking, but a confounding variable is that chronic nicotine administration itself has been shown to desensitize nicotine receptors over time and lead to antidepressant effects.[30] Smoking cessation itself is strongly associated with reduced depression, anxiety, and stress and improved positive mood and quality of life compared with continuing to smoke.[31] It has been hypothesized that snus' success when compared with conventional NRT as a cigarette substitute could be attributed to its MAO inhibiting properties. However, studies seem to suggest that for MAO inhibition, tobacco has to be pyrolysized (i.e., ignited as in cigarettes, cigars, and pipes). The competing theory is that the success of snus as a smoking alternative is due to its ability to deliver nicotine similar to that acquired through cigarettes, and twice as high as that acquired through NRT.[32] Furthermore, the use of snus, similar to cigarettes, offers a choice of brand, aesthetic rituals of use, and tastes of tobacco and thus has sensory effects that NRT products perhaps lack.

Snus vs conventional NRT: success rates in smoking cessation

The use of daily snus for smoking cessation has had a 54% success rate for complete abstinence, and a 60% success rate for great reduction in cigarette consumption.[33]

The debate over nitrosamine levels in snus

Opponents of snus sales maintain, nevertheless, that even the low nitrosamine levels in snus cannot be completely risk-free, but snus proponents point out that, inasmuch as snus is used as a substitute for smoking or a means to quit smoking, the net overall effect is positive, similar to the effect of nicotine patches.[34]

Snus, second-hand smoke, and the harm reduction perspective

In addition, this eliminates any exposure to second-hand smoke, further reducing possible harm to other non-tobacco users. This is seen by public health advocates who believe in "harm reduction" as a reason for recommending snus, as well as other NRTs, rather than continued use of methods of tobacco consumption that result in second-hand smoke.

This does not, however, eliminate any harm to health caused by the nicotine itself. Current research focuses on possible long-term side effects of nicotine on blood pressure, hypertension, and possible risk of pancreatic cancer due to tobacco-specific nitrosamines (TSNAs). TSNAs are the only component of tobacco shown to induce pancreatic cancer in laboratory animals.[35] Nicotine may also exacerbate pancreatic illness, because nicotine stimulates the gastrointestinal tract's production of cholecystokinin, which stimulates pancreatic growth and may be implicated in pancreatic cancer. Thus far, the evidence specifically implicating snus in pancreatic cancer is only suggestive.[36][37] Notably, the probability of developing pancreatic cancer from cigarettes is higher than the suggested chance of developing pancreatic cancer from snus.[38][39]

The effect of Swedish snus on blood pressure has been studied at Umeå University in a randomly selected population sample of 4,305 Swedish men between the ages of 25 and 74. In the study, published in November 2008, the researchers found no elevation of blood pressure in snus users who had never been smokers compared to tobacco nonusers.[40]