Summary
The smoking control policies recommended by the World Health Organization have achieved a slight decrease in the prevalence of smoking in developed countries, although the related mortality remains very high. The use of tobacco products other than cigarettes or medicinal nicotine (known as nicotine replacement therapy or NRT) has been proposed as a risk reduction strategy. Among tobacco products with less individual risk than cigarettes would be some types of smokeless tobacco with low nitrosamine content and modified cigarettes; both forms encompassed under the concept of PREP (Potentially Reduced Exposure Products) .
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The idea would be to promote these products to those who can not stop smoking or wish to reduce their risk without abandoning nicotine. We review the possible effects on the decrease of the prevalence and on the morbidity and mortality of the risk reduction strategies, including the PREPs, and analyze the possible implications that this measure could have in our environment. In Spain, the control measures for smoking are recent and still insufficient. Currently, the priority in Spain is, therefore, the development of control policies that have shown their effectiveness in ample. The commercialization and diffusion of new tobacco products, even of reduced potential risk, seems more a serious threat than an opportunity for the development of tobacco control policies.
Abstract
The smoking control policies recommended by the World Health Organization have achieved a slight decrease in smoking prevalence in the developed countries, although associated mortality is still very high. The use of tobacco products other than cigarettes and even medicinal nicotine (known as nicotine replacement therapy (NRT)) has been proposed as a risk reduction strategy. Among the tobacco products with less individual risk than cigarettes would be any type of tobacco without smoke (smokeless) with a low content in nitrosamines and modified cigarettes; both forms included under the PREP (Potentially Reduced Exposure Products) concept. The idea would be to promote these products among those who can not quit smoking or wish to reduce their risk without giving up nicotine intake. The possible effects of risk reduction strategies, including PREP, on the decreased prevalence and morbidity and mortality are reviewed, and the possible implications that this measure could have in our country are analyzed. Tobacco control measures in Spain are recent and still insufficient. Therefore, the current priority in Spain is the development of control policies that have shown to more than effective. The marketing and advertising of new tobacco products, even with reduced potential risk, seems more a serious threat than an opportunity for the development of smoking control policies.
Introduction
The current development of public policies on tobacco control recommended by the International Framework Convention, promoted by the World Health Organization, is leading to an average decrease of between 0.5 and 1% in the prevalence of smoking in the countries developed while it continues to increase in impoverished countries. Global mortality due to tobacco is currently estimated at 5.4 million people / year, which could exceed 8 million in 2030 if the same trend is maintained
1 .Due to the difficulties in implementing these control policies, its effects could be insufficient to reduce the morbidity and mortality related to tobacco consumption in the coming decades. This reality, together with the fact that nicotine addiction is sometimes difficult to break, has led institutions such as the Royal College of the United Kingdom and some experts to advocate, as a new risk reduction strategy, the use of tobacco products other than cigarettes, or medicinal nicotine - commonly known as nicotine replacement therapy (NRT) -. Among the tobacco products with less individual risk than cigarettes would be some kinds of smokeless tobacco with a low content of nitrosamines and modified cigarettes, both forms included under the concept of "products with potentially reduced exposure" (PREP, de potentially reduced exposure products ). Currently, with the exception of TSN, tobacco products with a lower toxic content are marketed by the tobacco industry. The idea would be to promote these products to those who can not stop smoking or wish to reduce their risk without abandoning nicotine consumption
2 .Given the enormous implications that would have within the policies of control of smoking, a previous detailed analysis seems reasonable. This review provides a brief review of risk reduction strategies, including PREPS, and their possible effects both on the decrease in prevalence and on morbidity and mortality due to tobacco use. Finally, the possible implications that this measure could have in our environment are analyzed.
Risk reduction strategies
The concept of risk reduction emerged in the 1980s in the context of injecting drug use, in response to two specific factors: first, the emergence of the AIDS epidemic among heroin users, and in secondly, the growing suspicion that the strategies adopted to deal with drug use had not been effective enough 3 .
In the case of smoking, risk reduction strategies were initially proposed within the scope of clinical practice, as a measure to reduce the diseases associated with cigarette smoking or as an intermediate step to achieve definitive abstinence. In the same way, as the perception of the risk of smoking increased, the tobacco industry expanded the tobacco market with new products other than cigarettes, which were also presented to the consumer as a reduction in harm, in order to reassure smokers and smokers. Keep your consumption.
Next, the different risk reduction proposals that appeared throughout the history of cigarettes, both from the clinical point of view and those made from the tobacco industry, are discussed.
Clinical strategies
Included here are proposals arising from the health sector whose purpose has been to reduce consumption to reduce risks, either as an objective in itself or as an intermediate step to achieve the total suppression of tobacco consumption.
Reduction in the number of cigarettes
Reducing the number of cigarettes has been a habitual strategy used by smokers to reduce the risk or to try to advance in the abandonment process. It was a proposal also used in the past by some professionals as a "realistic" solution for patients who can not or do not want to stop smoking completely. There is no scientific evidence that reducing the number of cigarettes actually reduces health risks, a seemingly paradoxical fact. The main explanation for this phenomenon is that people who are smokers, by reducing their consumption, tend to practice compensatory behaviors in an unconscious way (faster cigarettes, deeper inhalations, etc.) to obtain the same amount of nicotine as before The reduction. The result is a small decrease in the amount of nicotine inhaled and, consequently, in the tar and toxins that accompany it, a decrease that is not proportional to the number of cigarettes eliminated. For some diseases such as ischemic heart disease, a reduction of 10 cigarettes in a smoker of 20 cigarettes a day means a reduction of less than 10% of the risk; that is, 5 times less than expected due to this compensatory effect in the way of smoking 4 .
The possible benefits of reducing the number of cigarettes have been evaluated in several follow-up studies. Godtfredsen et al 5 analyzed the mortality rate for diseases related to tobacco consumption in smokers of more than 15 cigarettes per day, compared with a group that had reduced the amount by half and with individuals who had quit tobacco completely. Among those who reduced the number of cigarettes, no decrease in the mortality rate was observed. However, those who left the consumption completely saw their risk of dying reduced, in the 15 years of study, by 35%. No significant differences were found in relation to respiratory disease or cardiovascular mortality among smokers with more than 15 cigarettes and those who had reduced the number of cigarettes. Another recent study in Norway evaluated 50,000 participants, men and women, over 15 years and showed that reducing consumption (eg, 30 to 20 cigarettes) does not significantly reduce the risk of cancer, lung disease, myocardial infarction or cerebral infarction 6 ; Table 1 shows the data of that study. A recent review of a total of 31 publications concludes that a substantial reduction in the number of cigarettes has a marginal marginal benefit in health, much lower than expected.
Death cause No. of deaths RR (95% CI) for every 10 cigarettes less No. of deaths RR (95% CI) for every 10 cigarettes less
All causes 1,809 0.97 (0.90-1.04) 4,042 1.00 (0.94-1.05)
Cardiovascular disease 650 0.90 (0.79-1.03) 1.479 0.98 (0.89-1.08)
Ischemic heart disease 447 0.85 (0.73-1.01) 989 0.97 (0.87-1.10)
Cancer related to tobacco 453 0.91 (0.79-1.06) 935 0.99 (0.89-1.11)
Lung cancer 253 0.97 (0.80-1.18) 497 1.01 (0.87-1.17)
On the other hand, it is usually thought that smoking a few cigarettes a day does not entail excessive danger to health. However, there are studies that show that very small amounts of tobacco produce harmful effects on health 8 .
Gradual reduction of nicotine and tar
Described in 1979, the gradual reduction of nicotine and tar, through the weekly change of brand of cigarettes, is conceived as a strategy of transition and preparation towards complete abstinence, although many therapists have applied it with the aim of reducing consumption. Several studies have shown their effectiveness as another technique, within the psychological treatments to stop smoking, especially in the framework of multicomponent programs 9 .
Nicotine replacement therapy
TSN has been used classically as a therapy to stop smoking, although some smokers use it transiently for long distance trips, hospitalizations or while in smoke-free public spaces. Recently there is some evidence that temporary reduction strategies with fast-acting TSN (chewing gum), in smokers who initially do not want to stop smoking, can increase the rate of cessation in the medium term 10 . In any case, TSN or "clean" pharmacological nicotine is the only product with scientific evidence for a temporary risk reduction strategy 11 , and as such it is recognized in our country 12 .
Tobacco industry strategies
These proposals do not really respond to a risk reduction objective, but rather to commercial interests. However, given that at the time they were raised as such, especially light cigarettes, and that many smokers often adopt them with the idea of reducing the damage, they are included in this review.
Pure cigars or pipe
Pure cigars and pipe are other forms of tobacco smoking, although they have always been a minority. The tobacco industry widely promoted cigars in the nineties with the aim of increasing the market. The risks associated with these products are lower than those of cigarettes because those who consume them tend not to inhale the smoke, although they absorb a lot of nicotine through the oral mucosa. The result is that the risk of emphysema, lung cancer and laryngeal cancer is lower in people who smoke cigars, but they have a similar risk of oral and esophageal cancer than those who consume conventional cigarettes. 13 The largest study on the health effects of cigar smoking was developed in a group of 17,774 men aged 30 to 85 years. In the analysis, individuals who smoked cigars (1,546), compared to nonsmokers (16,228), presented, independently of other factors, an increased risk of coronary heart disease (27% more), of chronic obstructive pulmonary disease ( 45%) and cancer of the esophagus and lung (2 times higher). The risks increased significantly from 5 cigars per day 14 .
Cigarettes with filter
At the beginning of the fifties of the 20th century cigarettes with filters appeared. With the incorporation of filters, the objective of the industry was not to protect the health of smokers, but to reassure them to protect their own business profits, endangered by the appearance in 1954 of the first epidemiological studies that showed, without a doubt, that tobacco was a cause of lung cancer. At the beginning it was thought that the incorporation of filters could reduce the risk for some cancers related to tobacco, by significantly reducing the amount of tar. However, several cohort studies conducted in the USA. and the United Kingdom showed that lung cancer continued to increase between 1950 and 1980, despite the widespread use of filter cigarettes 15 .
Cigarettes low in tar and nicotine (light cigarettes)
With the incorporation of light tobacco in 1970, many smokers switched to low nicotine and tar brands believing that they would reduce the risk. This perception of lower risk was widely promoted by the tobacco industry and resulted in many smokers delaying the decision to stop smoking. In fact, the abstinence rate of consumers of light cigarettes is lower than that of conventional cigarette smokers (27% vs 53%, p <0.01), demonstrating the potential of these products to delay effective cessation 16 . In the European Union (EU), the denomination of light cigarettes has not been allowed since 2003, but these products are still sold with other names or other external signs on their packaging.
The tar content of cigarettes is measured by machines that "smoke" artificially; Much of the reduction observed is due to the dilution of the smoke through the holes made in the filter by the manufacturers. In real life, it is inevitable that smokers will plug these holes with their fingers, thereby inhaling a much larger amount of tar. Therefore, the nicotine / tar ratio of light cigarettes is actually similar to that of conventional cigarettes 17 . In fact, the absorption of tar and nicotine is higher than that indicated by the pack of cigarettes and the ISO 18,19 standards. In Spain, only the Center for Research and Quality Control, attached to the National Consumer Institute, of the Ministry of Health and Consumption, is certified to evaluate tobacco products.
At first it was thought that light cigarettes could contribute to a reduction in the risk of lung cancer 21 . However, in the decades following the appearance of the light cigarette, the overall mortality from lung cancer in the USA, in both sexes, did not stop increasing, going, from 1979 to 1997, from 98.5 to 153.3 cases per 100,000 inhabitants, which denied the initial idea of a lower risk 22 . In spite of everything, to this day, many smokers still believe they feel protected by consuming cigarettes with a filter and low tars 23 .
Products with reduced potential risk
Conceptually, PREPs are defined as those products that contain nicotine, but lower amounts of tar and other toxic than conventional tobacco (mainly nitrosamines), a definition that includes some forms of smokeless tobacco, in addition to modified cigarettes.
Smokeless tobacco ( smokeless )
Under the term smokeless , different forms of tobacco are included (in paste, powder, snuff, etc.) whose common characteristic is that they are consumed orally or nasally, but without combustion; therefore, without smoke. In general, they are considered to have fewer health risks than cigarettes. Traditionally smokeless has been a form of tobacco consumption widespread in some Asian countries. In developed countries, smokeless is rare, with the exception of Sweden, where the so-called snus is consumed since 1637. The snus is a bag of moist tobacco paste that is placed under the upper lip, for absorption through the buccal mucosa. The risk of this form of tobacco is low when compared to cigarettes, but it is also a cause of cancer. The low prevalence of lung cancer observed in Sweden, compared to other developed countries, 24 has led some experts to look at this product as a possible alternative for a viable risk reduction strategy.
Several studies have evaluated snus as a "protective" factor of cigarette smoking. On the one hand, it would delay the start among the youngest and, on the other, it would increase the cessation among cigarette smokers. In Sweden it has been observed that 47% of young people who experimented with tobacco became cigarette smokers, whereas this only occurred in 20% of young people who started using snus . Also according to the Swedish experience, those who used snus stopped smoking by 66%, while with nicotine gum they left 47% and with a 32% patch 25 . On the contrary, in the USA, where it is also consumed, although to a lesser extent, it has been proven that young people who start using snus tend to start more easily in the consumption of cigarettes than those who do not use it (27). against 12.9%) 26 . On the other hand, adult smokers who use snus try to quit cigarettes more frequently but have lower rates of abstinence than those who do not use cigarettes (12% vs 21%) 27,28 .
Modified cigarettes
Modified cigarettes are conventional cigarette-shaped devices that release nicotine without combustion, but through a heating process (electronic or chemical) 29 , hence they are also known as electronic cigarettes ( e-cigarettes ). At present, various tobacco companies have commercialized these alternative cigarettes in different countries, including Spain. Its legal situation in the EU is unclear because it is not a tobacco product, but it has not passed the filters of pharmaceutical products, despite containing nicotine, given that it is not clear that they are marketed for medicinal purposes 30 .
In Spain, brands like Ruyan ® and Similar ® have recently appeared; the former uses an electronic system to heat and release nicotine, whereas Similar uses a chemical system. In our country they are sold in some cinemas, gas stations and airlines, although at the moment their commercial penetration is reduced. With some brands (such as Eclipse ® , marketed in the US by RJ Reynolds) it has been proven that, although they release less tar than conventional cigarettes, they produce more carbon monoxide, so their risk of heart attack would be even greater. Shiffman et al 32 have pointed out that the idea that these modified cigarettes reduce risk can have an adverse effect, by preventing the definitive cessation of tobacco consumption, or even encourage former smokers to try these new products. At the moment there are no studies that have shown that modified cigarettes are safer than conventional cigarettes 33 . For several reasons, it is to be feared that the promotion of these products may undermine some of the policies of proven efficacy in tobacco control 34 .
Advantages and disadvantages of risk reduction strategies
To assess the harm reduction in smoking, it is necessary to separate the individual impact of the population impact. From the individual point of view, it is possible that, in certain circumstances, total abstinence is not a realistic goal and a harm reduction strategy can be proposed. The therapeutic option would be "clean" TSN or nicotine, since it is the only product that has shown scientific evidence for a temporary risk reduction strategy. In addition, the TSN, although it is a freely available product, is subject to the usual pharmaceutical regulation.
From the population point of view, classical clinical strategies (cigarette reduction, etc.) have not shown benefits, and those of the industry have only served to maintain the epidemic. With regard to the products of reduced toxicity or PREP, on which the debate is currently focused, they present several disadvantages 35 . First, smokeless tobacco has not been shown to reduce the population risk, since it is not clear that the introduction of new ways of dispensing nicotine contributes to reducing tobacco consumption among the population. On the contrary, the data indicate that the tobacco industry could take advantage of the liberalization of snus to attract adolescents and young adults to nicotine consumption 33 . The strategy that should be followed in young people is not encouraging them to consume snus , as an alternative, but the development of preventive and treatment programs 36,37 .
The promotion of snus and other forms of smokeless tobacco could reduce the risks in the population of smokers, but at the expense of increasing the use of snuff in the population as a whole, which clearly would not be a benefit, but a risk added In fact, in Norway, where snus is also commercialized, its consumption has increased by around 11% in all men and up to 18% in the group of 16-24 years, without evidence that the prevalence of conventional smoking 38 .
- Evidence about smokeless tobacco 39
- It is a toxic and carcinogenic product
- Its promotion has increased the global sales of tobacco products in some countries
- The increase in consumption has occurred especially in adolescents and young adults
- Its use has not been associated with a reduction in the start of cigarette consumption or its prevalence
- It does not have a role in the cessation and in Sweden its effect is contradictory
- Countries with less tobacco prevalence also consume less smokeless tobacco
- There is no data on its effectiveness as a method for cessation
- The prevalence of smoking is high among consumers of smokeless tobacco
- It is generally used for a partial replacement of cigarettes rather than for a complete substitution
- The evidence to promote it as a public health strategy is weak and inconclusive
Another limitation for its use would be the need for a new regulation. At the moment, the European directive on tobacco products 41 prohibits in the EU the commercialization of new forms of tobacco, including those for oral use such as snus , except in countries of traditional use such as Sweden and Norway. If it were allowed to market these products, it would be difficult to avoid the reappearance of brand advertising whose main business is traditional cigarettes and not snus . Given that tobacco companies face a global regulation of advertising by the Framework Agreement, it seems very possible that they use the new products in order to weaken and avoid such regulation. In this sense, there are data that show the interest because it is legislated in favor of the commercialization of these new tobacco products erroneously classified as "healthier" 42 .
Implications of the use of potentially reduced exposure products in our environment
The main argument of the supporters of the promotion of PREP is that it would be an effective measure to reduce the risks among the population of smokers, which on the other hand they still consider too high.
Recently, the World Health Organization has established 6 policies to reduce and prevent tobacco use, summarized in the so-called MPOWER measures plan, which does not include risk reduction. This report also highlights that only 5% of the world population is covered by global tobacco control policies, and that few tobacco users receive the necessary help to stop smoking. In Spain only 12% of smokers request professional help to stop smoking, while in the United Kingdom, with the highest percentage of demand for help, the figure reaches 41% of smokers and the average in the EU is 18% 44 . This is a paradoxical fact, taking into account that, although there is a lack of evidence to assess the results of long-term smoking cessation, 45 the treatment of smoking is cost-effective and is widely recommended. 46
In Spain, the control measures for smoking are recent and still insufficient. The priority in our country is, therefore, the development of control policies that have shown their effectiveness in ample way ( table 3 ). Therefore, the debate should focus not so much on the possible goodness of risk reduction, but rather on its timing, in order to avoid the division between clinical professionals, more concerned with individual health, and those with a broader vision of the public health 47 . That is to say, what is the point of risk reduction when such basic and proven measures as smoke-free spaces, tobacco taxation or the treatment of smokers are beginning to make their way, still with enormous difficulties, in the majority of countries? 48
Effective policies in the control of smoking
1
Annual increase of tobacco taxes (so that the final price is above the CPI). Withdrawal of the price of tobacco from the calculation of the CPI
2
Regular tobacco additives without the inclusion of carcinogenic products per se or substances that directly or indirectly increase their addictive capacity
3
Regular labeling and packaging, make them less attractive, and generic packaging without attractive logos
4
Limitation of the points of sale to the official points (tobacconists), prohibition of vending machines and "second channel" (hotels, kiosks, etc.)
5
Total prohibition of tobacco advertising, promotion and sponsorship. Measures to compensate for indirect promotion in film and television without prior censorship (declaration of subsidies for product placement , health warnings, etc.)
6
Public spaces totally smoke-free without exceptions or ambiguities
7
Information and education on the risks of active and passive tobacco, on an ongoing basis (similar to campaigns to prevent traffic accidents in terms of investment and intensity)
8
Public subsidies for smoking cessation treatments (including drugs) and liberalization of the sale of nicotine replacement therapy
9
Health warnings by images, rotating and combining negative and positive messages in packets of tobacco or generic brands
10
Inspection system for tobacco regulations with state, regional and local development. Sanctions of dissuasive amount with agile procedures of processing and execution
The background shows how the tobacco industry has been able to periodically develop new products and place them on the market as "safer", thus managing to stop the abandonment process among many smokers. To this day, in Spain the commercialization and diffusion of new tobacco products, even those with reduced potential risk, seem more a serious threat than an opportunity for the development of smoking control policies.