The Lesser Evil
They smoke because of nicotine, they die from tar
D. G. Zaridze, "First-hand Science"
Can smoking be safe? Definitely not. The best choice for any person is a complete rejection of tobacco. But despite all the calls for a healthy lifestyle and scary pictures on cigarette packs, millions of people around the world do not give up this addiction. A compromise way is to reduce the harm from smoking. Both world practice and the experience of our country prove that this is quite real. The reduction of mortality from cancer related to smoking is the main, and perhaps the only achievement in the field of cancer prevention in Russia.
The link between cigarette smoking and lung cancer was first discovered in the 1950s by the outstanding English epidemiologist Richard Doll. Based on a study of patients in two dozen London hospitals, he concluded that the risk of developing this disease increases in proportion to the number of cigarettes smoked.
His report, published by the British Medical Research Council, became a real sensation. At that time, 80% of the adult population in the UK were smokers, and no one suspected the dangerous consequences of this habit. The scientist himself quit smoking after his discovery.
In the United States, lung cancer mortality has decreased by almost 40% in 20 years since 1990. As you know, mortality in this type of cancer reaches 85%, despite all the successes of modern medicine. Graphs of the dynamics of tobacco consumption and mortality clearly illustrate the fact that the reason for the decrease in the number of cases was the lower prevalence of smoking, primarily among men. A drawing from the cancer.opg website.
Thirty years later, Professor Doll took part in the large scientific conference "Tobacco: the main international threat to health" held in Moscow in 1985 as honorary president. The conference was chaired by the author of these lines (at that time – the head of the program "Lifestyle Factors and Cancer" of the International Agency for Research on Cancer (IARC)) and Professor Richard Peto from Oxford University.
Leading epidemiologists from Europe, the USA, Japan and China came to the conference to discuss together the problems of combating smoking and its consequences. Experts have concluded that there is a fairly simple way to reduce the risk of lung cancer in smokers, as well as, probably, other forms of cancer.
Richard Doll:
"Death in old age is inevitable, but death before old age is not. In previous centuries, it was believed that a person was allotted 70 years of life, and only one in five lived to that age. However, the current situation for non-smokers in Western countries is the opposite: only one in five dies before the age of seventy, and the death rate among non-smokers is still declining, which gives hope, at least in the developed countries of the world, where death before the age of 70 is rare. In order for this "promise" of a long life to be properly realized, it is necessary to find ways to limit the enormous damage that tobacco is currently causing, and to convey not only to millions of people in developed countries, but also to the population of the whole world how much those who continue to smoke are shortening their lives."
Deadly smoke
In the smoke of a burning cigarette, which a smoker inhales, it is possible to detect over 5 thousand different chemical compounds. At the same time, both the gaseous components of cigarette smoke (from carbon monoxide to prussic acid) and the smallest solid particles consisting mainly of nicotine, water and the so-called resin pose a danger to the smoker.
It is the resin that contains most of the carcinogenic substances that tobacco smoke is so rich in: polycyclic aromatic hydrocarbons (PAHs), primarily benz(a)pyrene; tobacco-specific nitrosamines (TSNA); aromatic amines; as well as polonium‑210, arsenic and heavy metals (beryllium, nickel, chromium, cadmium). All these substances according to the IARC classification belong to the I class of carcinogenic hazard.
In the mid-1970s, the British psychiatrist Michael Russell, one of the active fighters against tobacco use, formulated the concept of "reducing the harm caused by smoking" (Tobacco Harm Reduction). According to Russell, "a new approach to safer smoking is cigarettes with low tar content and medium nicotine levels." He also owns the oft-quoted saying that "a smoker smokes because of nicotine, but dies from tar." In this regard, he proposed to keep the average level of nicotine in tobacco products, and to reduce the tar content to low or very low.
Russell's ideas were confirmed in epidemiological studies by Doll and Peto. In an article published in 1978, they gave their explanation for the decrease in mortality from lung cancer in young men observed at that time. According to scientists, this generation, unlike the previous ones, smoked cigarettes with a filter, which contain significantly less tar and, accordingly, carcinogenic substances. At the same time, tobacco consumption in the UK in the 1970s has not changed in any way, as there have been no significant improvements in the treatment of lung cancer.
At that time, the level of tar and nicotine in Soviet and imported cigarettes to our country was very high. For example, in strong cigarettes without a filter, the tar content could exceed 30 mg (for comparison: according to the domestic "Technical Regulations on Tobacco Products", since 2016, the tar and nicotine content in the smoke of one cigarette with a filter cannot exceed 10 and 1.0 mg, respectively). And at the Moscow conference in 1985, it was decided to recommend lowering the concentration of tar in tobacco products to 15 mg/sig.
However, not all of those who took part in the discussion agreed with this proposal. Official representatives of the World Health Organization and the IARC leadership categorically objected to "half measures". In their opinion, all efforts should be directed exclusively at the complete rejection of tobacco.
The categorical position of the "purists", the fighters for the ideological purity of smoking prevention, looked quite convincing. And only our confidence in the exceptional importance of what we offer and the enormous authority of Professor Doll allowed us to include in the final document a section on reducing the concentration of tar in tobacco smoke. Nevertheless, Professor Peto, who fervently defended this point of view, closed the doors to WHO and IARC for five years, where before that he was the main expert in the field of prevention of non-communicable diseases.
And from that moment on in the USSR, and then in In Russia, the fight against smoking began at the state level. Based on the recommendations of specialists, in 1988, the regulation on the maximum permissible concentrations (MPC) of resin in cigarettes and cigarettes on sale was adopted. As a result, very high concentrations of resins per cigarette dropped to moderate (15 mg), and then relatively low (12 mg).
Life and death lines
The effect of the measures taken to combat smoking was not long in coming. Mortality from lung cancer in Russia began to decline already in the 1990s. In the next two decades, this indicator fell by 40% for men, and by a quarter for women.
Unlike Western countries, in Russia the prevalence of smoking in 1993-2008 grew – it began to decline only in 2009 (above). At the same time, the incidence and mortality from lung cancer (bottom right), as well as from other forms of cancer associated with smoking, have been declining since the early 1990s. The reason is the decrease in the concentration of carcinogenic substances in cigarette tobacco smoke, which followed the adoption in 1988. regulations on the MPC of resin in cigarettes and cigarettes (Zaridze, Mukerya, 2018).
Mortality from other forms of malignant tumors, the cause of which is considered to be smoking, has also decreased: cancer of the lip, oral cavity, pharynx, larynx and esophagus. The same trend took place in the former Soviet republics, which were covered by the regulations on reducing the level of tar in tobacco products, adopted by the Ministry of Health of the USSR in 1988.
Meanwhile, the sale of cigarettes in Russia has more than doubled: from 200 billion units in 1996 to 425 billion units in 2006. It would seem that along with this, the incidence of lung cancer and, accordingly, mortality should have increased. But it turned out the opposite. And the point here is not in the achievements of medicine: the 5-year survival rate of lung cancer patients has not changed much in 30 years. The only reason is that every cigarette smoked now contained fewer carcinogenic substances.
What is curious: if we compare the death curves from lung cancer and all malignant neoplasms, we will find a striking similarity in them. Until 1993, there was a steady growth, then a turning point, and then a decline begins.
In Russia, tobacco consumption increased in 1993-2008, while the incidence and mortality from lung cancer and other forms of cancer associated with smoking began to decline since the early 1990s. The reason is the adoption in 1988 of the regulation on the maximum permissible concentrations (MPC) of resin in cigarettes and cigarettes (Zaridze, Mukerya, 2018).
This overall decrease in cancer mortality was almost exclusively due to those diseases caused by smoking. Almost the only exception is stomach cancer. Mortality from this disease in our country, as well as around the world, began to decline since the middle of the last century. And this trend is connected not with achievements in the field of early diagnosis or treatment, but with socio-economic changes and the overall improvement of people's quality of life.
In the case of oncological diseases, quitting smoking at any time, at any stage of treatment leads to a significant improvement in the prognosis. It is estimated that if a patient gives up smoking after being diagnosed with cancer, the risk of death can be reduced by 30-40%. In the case of some forms of cancer, the benefits of quitting smoking may be equivalent to or even surpass the effects of modern antitumor therapy (Dressler, 2003).
Of two evils
Over the past 40 years, tobacco consumption has decreased in many countries of the world, but millions of people still continue to smoke and die from diseases associated with this harmful habit. In the long term, the number of people who quit smoking is estimated to be extremely low: despite significant efforts to control the use of tobacco products and actively disseminate information about the dangers of tobacco, the number of smokers is growing.
A clear proof of this trend is the increase in the incidence and mortality from lung cancer in women in some countries, including Russia, observed in recent years. Cases of this disease have become more frequent among Russians by 20%, which can only be attributed to an increase in tobacco consumption.
In order to get closer to the goal set by many States to reduce the prevalence of smoking and, accordingly, to reduce morbidity and mortality from diseases associated with it, additional measures are needed. In addition to anti-smoking propaganda, a ban on smoking in public places and other popular methods of fighting for a healthy lifestyle, alternative ways to overcome nicotine addiction can and should be used.
One of them is electronic nicotine delivery systems (ESDS), including electronic cigarettes (ES) and tobacco heating systems (SNTS). According to available scientific data, the aerosol released during their use contains fewer carcinogens and other toxic substances than ordinary tobacco smoke. If tobacco is heated to 800-900 ° C in traditional cigarettes, then in SNT it is only up to 250-300 ° C, and in this case tobacco burning does not occur. And, as you know, most of the toxic and carcinogenic substances of tobacco smoke are formed at very high temperatures.
In addition, a study of the blood and urine of ES users revealed a lower content of compounds – markers of toxic and carcinogenic substances in them compared to ordinary smokers.
So with the help of such electronic devices, a smoker can get the amount of nicotine he needs, being exposed to less toxic and carcinogenic substances than when smoking conventional cigarettes. This approach, in principle, is quite consistent with the concept of "harm reduction".
Electronic, or alternative, nicotine delivery vehicles (ESDS) can be divided into two main groups: so-called vapes (including electronic cigarettes) and tobacco heating systems (SNT).
Vapes use a nicotine-containing liquid that turns into a highly dispersed vapor (aerosol) when heated, which the user inhales. There are also nicotine-free vaping liquids that contain only propylene glycol, glycerin, water and a variety of flavors.
In tobacco heating systems, an example of which is IQOS, not liquid is used, but specially treated tobacco leaves. To do this, they are crushed with the addition of water, glycerin, guar gum and cellulose fibers. The device heats this mixture to a lower temperature than in conventional cigarettes, so tobacco does not burn. Accordingly, it is not smoke that gets into the smoker's lungs, but tobacco aerosol.
In addition to vapes and SNTS, there are also hybrid devices that combine real tobacco and nicotine-containing liquid.
Of course, in this case we are not talking about the promotion of ES among the general population. After all, the alkaloid nicotine, which enters the body with their help, remains the same potentially dangerous narcotic substance that is addictive, and also, according to some data, increases the risk of certain cardiovascular pathologies. But for people who are unable to give up a dangerous habit and at the same time would like to reduce the harm of tobacco consumption, ESDS can become an alternative to the usual cigarette. Moreover, there is evidence that the use of electronic means gradually helps to get rid of nicotine addiction altogether.
You can't quit smoking
Now in many countries, national state and public agencies dealing with prevention issues recommend smokers with severe tobacco addiction to switch to ESDN.
According to the former executive body of the Department of Health and Social Security of England (Public Health England), 2.9 million Britons use ES and tens of thousands each year successfully quit smoking with their help. Based on the report of the Council of Experts, the Science and Technology Committee of the lower house of the UK Parliament concluded that in passive smokers, inhalation of aerosol does not lead to negative health consequences or they are significantly weaker than from the smoke of conventional cigarettes. And in August 2018, parliamentarians proposed to the British Ministry of Health to use ESDN more actively as a means of quitting smoking. However, at the same time, the need to prevent the use of ESDS by non-smokers was emphasized.
Following the UK, other countries have recognized relatively less harm to the ESDN. In France, the Supreme Council of Public Health recommended informing medical professionals and smokers that a complete transition to the use of ESDS can contribute to quitting smoking and reducing the risk associated with tobacco use.
In July 2020, the U.S. Food and Drug Administration (FDA) authorized the promotion of one of the ESDS as a "modified risk" tobacco product. This decision is based on scientific studies that have shown that replacing traditional cigarettes with electronic ones reduces the impact on the body of 15 dangerous and potentially dangerous substances, including toxic and carcinogenic compounds such as formaldehyde, acrolein, benz(a)pyrene, etc.
WHO takes a more cautious position, but recognizes that a complete and rapid transition of adult smokers from conventional tobacco products to the use of "clean" and properly regulated ESDS can help reduce the risk to their health. (WHO makes an exception for pregnant women who, in principle, do not recommend smoking.)
Such a change of nicotine "carriers" is especially important for cancer patients, many of whom cannot give up a bad habit even after diagnosis. It has been proven that smoking traditional cigarettes worsens the prognosis of this disease, including overall survival and the development of new tumors.
So far, in our country, ESDS are legally equated to ordinary cigarettes (Federal Law No. 303-FZ of July 31, 2020), and Russian society is categorically opposed to their distribution.
Quitting smoking reduces the risk of lung cancer. And it's never too late to quit (Halpern, 1993).
It would seem that the analysis of scientific data and international experience should be a reason to reconsider this point of view and plan new measures for the prevention of smoking in Of Russia. However, often vital documents in our country are developed not on the basis of scientific facts, but from a moralistic position. Smoking is evil, which means that any compromise solutions are excluded. The advantage of such a position is that it does not require proof of its validity.
Smoke without fire
The debate about how safe the use of vapes (electronic nicotine delivery systems, ESDS) is and whether they can become an alternative to conventional cigarettes began a long time ago. Until now, experts have not come to a consensus – there is simply not enough scientific data for final conclusions. Thus, a WHO report made in 2016 states that, on average, the level of toxic substances in the aerosol "electronok" is lower or even much lower than in cigarette smoke. However, sometimes the concentrations of formaldehyde and heavy metals in it may even exceed those in cigarettes. Moreover, these fluctuations are noted even for products of the same brand. Why this is happening is not entirely clear.
The main argument against alternative methods of nicotine delivery is that the alleged harm of nicotine has long been proven. True, there are also nicotine-free vapes (electronic means of delivery of products that are not nicotine, or ESDPN). But they can not be called safe for health. There is evidence that the flavors contained in them can have a toxic effect on cells, provoke inflammation in the respiratory tract and reduce the body's resistance to viral infections.
According to WHO, at the moment there are no reliable figures showing how much electronic cigarette substitutes are safer than conventional ones. Moreover, complex mixtures of substances contained in liquids and vaping aerosols can have a toxic effect even at low concentrations of harmful compounds. And long-term studies are required to assess their effect on humans.
And "passive" smokers need to remember that, although the nicotine content in the vaping aerosol is less than in cigarette smoke, it is still one or two orders of magnitude higher than in the ambient air.
The reduction in morbidity and mortality from lung cancer alone over the past quarter century has saved the lives of almost half a million Russians, as well as tens of thousands of citizens of other former Soviet republics. This is a weighty proof of the effectiveness of the concept of "reducing the harm caused by smoking" for the prevention of cancer.
Now we just need to take the next step. Switching to ESDN for people who cannot quit smoking will significantly reduce mortality from cancer and other chronic non-communicable diseases associated with tobacco use. Just as it happened once before in our country as a result of a decrease in the tar content in cigarettes.
Literature
Zaridze D. G. Tobacco – the main cause of cancer. Moscow: Ima-press, 2012. 208 p.
Zaridze D. G., Kaprin A.D., Stilidi I. S. Dynamics of morbidity and mortality from malignant neoplasms in Russia // Questions of oncology. 2018. No. 5. pp. 578-591.
Zaridze D. G., Mukeria A. F. Prevention of smoking-associated forms of cancer: the concept of harm reduction // Practical oncology. 2020. Vol. 21. No. 3. pp. 197-229.
Doll R., Hill A. B. Smoking and carcinoma of the lung; preliminary report // Br. Med. J. 1950. V. 2(4682). P. 739–748.
Peto R. Overview of cancer time-trend studies in relation to changes in cigarette manufacture // IARC Sci. Publ. 1986. V. 74. P. 211–226.
About the author: David G. Zaridze – MD, Corresponding Member of the Russian Academy of Sciences, Professor, Head. Department of the National Medical Research Center of Oncology named after N.N. Blokhin of the Ministry of Health of the Russian Federation.
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