Smoking facts and evidence

Read the key facts about smoking and cancer risk, and find the supporting evidence from academic research and scientific studies to see why we say what we do.

Experts agree that tobacco is the single biggest avoidable cause of cancer in the world [1, 2]. Smoking causes over a quarter (28 per cent) of cancer deaths in the UK and nearly one in five cancer cases [3, 4].

And smoking doesn’t only cause cancer. It also causes tens of thousands of deaths each year in the UK from other conditions, including heart and lung problems [3]. Worldwide, tobacco caused an estimated 5.1 million deaths in 2004 – that’s one every six seconds [5].

Around half of all regular smokers will be killed by their habit if they continue to smoke [6, 7]. And half of those will die in middle age, losing between one and two decades of life compared with non-smokers [1, 3, 7, 8].

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

2. Swerdlow AJ, Peto R, Doll R. Epidemiology of cancer. In: Oxford Textbook of Medicine. Oxford, UK: Oxford University Press; 2010:299–332. View resource

3. Peto R, Lopez AD, Boreham J, Thun MJ. Mortality from smoking in developed countries 1950 - 2005 (or later). View resource

4. Parkin DM, Boyd L, Walker LC. 16. The fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010. British Journal of Cancer. 2011;105(S2):S77–S81. View resource

5. WHO. Global health risks: mortality and burden of disease attributable to selected major risks. 2009. View resource

6. Doll R, Peto R, Wheatley K, Gray R, Sutherland I. Mortality in relation to smoking: 40 years’ observations on male British doctors. BMJ (Clinical research ed.). 1994;309(6959):901–11. View summary on PubMed

7. Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking: 50 years’ observations on male British doctors. BMJ (Clinical research ed.). 2004;328(7455):1519. View summary on PubMed

8. Jha P. Avoidable global cancer deaths and total deaths from smoking. Nature reviews. Cancer. 2009;9(9):655–64. View summary on PubMed

Smoking increases the risk of at least 14 cancers, including cancer of the lung, larynx (voice box) oesophagus (gullet), mouth and pharynx (upper throat), bladder, pancreas, kidney, liver, stomach, bowel, cervix, ovary, nose and sinus as well as some types of leukaemia [9-11]. There is some evidence that smoking could cause breast cancer [11-15].

After lung cancer, the upper aerodigestive tract cancers (mouth, upper throat, voice box and gullet) have the highest proportions of cancer cases caused by smoking – population attributable fractions, or PAFs, of more than 6 in 10 [4].

References

4. Parkin DM, Boyd L, Walker LC. 16. The fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010. British Journal of Cancer. 2011;105(S2):S77–S81. View resource

9. Gandini S, Botteri E, Iodice S, et al. Tobacco smoking and cancer: a meta-analysis. International journal of cancer. Journal international du cancer. 2008;122(1):155–64. View summary on PubMed

10. Cogliano VJ, Baan R, Straif K, et al. Preventable exposures associated with human cancers. Journal of the National Cancer Institute. 2011;103(24):1827–39. View summary on PubMed

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

12. Manjer J, Tjonneland A, Olsen A, et al. Active and passive cigarette smoking and breast cancer risk : Results from the EPIC cohort. International Journal of Cancer. 2014;134:1871–1888. View summary on PubMed

13. Boyd NF, Cantor KP, Hammond SK, Johnson KC, Miller AB. Canadian Expert Panel on Tobacco Smoke and Breast Cancer Risk.; 2009. View resource

14. Gaudet MM, Gapstur SM, Sun J, Diver WR, Hannan LM, Thun MJ. Active smoking and breast cancer risk: original cohort data and meta-analysis. Journal of the National Cancer Institute. 2013;105(8):515–25. View summary on PubMed

15. DeRoo L a, Cummings P, Mueller B a. Smoking before the first pregnancy and the risk of breast cancer: a meta-analysis. American journal of epidemiology. 2011;174(4):390–402. View summary on PubMed

More than four in five UK lung cancers are caused by smoking [3, 4]. Lung cancer is the most common cause of cancer death in the UK and accounts for around two thirds (68 per cent) of smoking-related cancer deaths [3, 16].

People who smoke were first shown to be more likely to develop lung cancer than non-smokers in 1950 [17]. This study found that people who smoked around 20 cigarettes a day had 26 times the lung cancer risk of non-smokers. And people who smoked around three cigarettes a day still had six times the lung cancer risk of non-smokers.

After these first results came out, UK scientists began a large long-running study of smoking in British doctors, which Cancer Research UK has helped to fund, that has told us a lot about the dangers of smoking [18]. This study has found similarly huge risks associated with smoking. Men who smoked at  25 or more cigarettes a day had over 24 times the risk of dying from lung cancer as people who had never smoked [7].

There are long time lags between changes in the number of people who smoke and the number of people who develop lung cancer due to smoking [1, 5, 8]. So rates of lung cancer in the UK reflect smoking rates decades earlier.

We cannot exactly calculate a person’s lung cancer risk based on how many cigarettes they smoke or the number of years they have been a smoker. But research has shown that lung cancer risk is greatest among those who smoke the most cigarettes, over the longest period of time, having started at the youngest age [1, 11].

Although both have an effect on risk, the number of years someone has spent smoking is more important than the number of cigarettes they smoke a day [19]. This means that overall, smoking 20 cigarettes a day for 20 years is even worse for you than smoking 40 a day for 10 years.

 

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

3. Peto R, Lopez AD, Boreham J, Thun MJ. Mortality from smoking in developed countries 1950 - 2005 (or later). View resource

4. Parkin DM, Boyd L, Walker LC. 16. The fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010. British Journal of Cancer. 2011;105(S2):S77–S81. View resource

5. WHO. Global health risks: mortality and burden of disease attributable to selected major risks. 2009. View resource

7. Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking: 50 years’ observations on male British doctors. BMJ (Clinical research ed.). 2004;328(7455):1519. View summary in PubMed

8. Jha P. Avoidable global cancer deaths and total deaths from smoking. Nature reviews. Cancer. 2009;9(9):655–64. View summary in PubMed

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

16. Cancer Research UK. Lung Cancer Mortality. View resource

17. Doll R, Hill AB. Smoking and carcinoma of the lung: Preliminary report. British Medical Journal. 1950;2(4682):739–48.

18. Doll R, Hill AB. The mortality of doctors in relation to their smoking habits: a preliminary report. British Medical Journal. 1954;1(4877):1451–5. View resource

19. Flanders WD, Lally CA, Zhu B, Henley SJ, Thun MJ. Lung Cancer Mortality in Relation to Age , Duration of Smoking , and Daily Cigarette Consumption : Results from Cancer Prevention Study II Lung Cancer Mortality in Relation to Age , Duration of Smoking , and Daily Cigarette Consumption : Results from Canc. Cancer Research. 2003;63:6556–6562. View summary in PubMed

Although the risk of an early death increases the more you smoke, people who think of themselves as light or occasional smokers also have an increased risk compared to people who don’t smoke [20, 21]. One study found that people who smoked up to four cigarettes a day were about 50 per cent more likely to die prematurely than non-smokers [20]. And the Million Women study found that women who smoked up to 10 cigarettes a day were twice as likely to die prematurely than non-smokers [21].  

Large studies looking at the health risks of smoking, such as the British Doctors Study and the Million Women Study, have found that people smoking between 1 and 14 cigarettes a day are at least seven times as likely to die from lung cancer than people who have never smoked [7, 21, 22]. And one study found people who smoked between 5 and 9 cigarettes a day had a higher risk of dying from lung cancer, or any type of cancer [20].

References

7. Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking: 50 years’ observations on male British doctors. BMJ (Clinical research ed.). 2004;328(7455):1519. View summary on PubMed

20. Bjartveit K, Tverdal A. Health consequences of smoking 1-4 cigarettes per day. Tobacco control. 2005;14(5):315–20. View resource

21. Pirie K, Peto R, Reeves GK, Green J, Beral V. The 21st century hazards of smoking and benefits of stopping: a prospective study of one million women in the UK. Lancet. 2013;381(9861):133–41. View summary on PubMed

22. Doll R, Peto R, Boreham J, Sutherland I. Mortality from cancer in relation to smoking: 50 years observations on British doctors. British journal of cancer. 2005;92(3):426–9. View resource

A large number of studies have shown that stopping smoking can greatly reduce the risk of smoking-related cancers, compared to continuing to smoke [1, 11]. And the earlier you stop, the better [7, 21, 23]. 

The latest results from the British Doctors’ Study show that stopping smoking before the age of 30 meant  that life expectancy remained similar to that of a non-smoker [7]. And even people who quit smoking when they were about 60 years old lost fewer years of life to smoking than those who continued [7].

 

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

7. Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking: 50 years’ observations on male British doctors. BMJ (Clinical research ed.). 2004;328(7455):1519. View summary on PubMed

21. Pirie K, Peto R, Reeves GK, Green J, Beral V. The 21st century hazards of smoking and benefits of stopping: a prospective study of one million women in the UK. Lancet. 2013;381(9861):133–41. View summary on PubMed

23. Jha P, Ramasundarahettige C, Landsman V, et al. 21st-century hazards of smoking and benefits of cessation in the United States. The New England journal of medicine. 2013;368(4):341–50. View summary on PubMed

The evidence for the health benefits of cutting down the number of cigarettes you smoke is mixed. Some studies have shown that reducing your cigarette consumption, compared to carrying on smoking the same amount, has benefits for lung cancer risk and overall survival [24-26]. But other studies found benefits only with quitting completely [27, 28].

However if you reduce the amount you smoke you may be more likely to stop smoking in future [29-33]. So although you only experience the full health benefits if you stop smoking altogether, cutting down can be a good first step, if you find it too difficult to quit completely in one go.

 

References

24. Gerber Y, Myers V, Goldbourt U. Smoking reduction at midlife and lifetime mortality risk in men: a prospective cohort study. American journal of epidemiology. 2012;175(10):1006–12.

25. Godtfredsen NS, Prescott E, Osler M. Effect of smoking reduction on lung cancer risk. JAMA : the journal of the American Medical Association. 2005;294(12):1505–10. View summary on PubMed

26. Song Y-M, Sung J, Cho H-J. Reduction and cessation of cigarette smoking and risk of cancer: a cohort study of Korean men. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2008;26(31):5101–6.

27. Tverdal A, Bjartveit K. Health consequences of reduced daily cigarette consumption. Tobacco control. 2006;15(6):472–80. View resource

28. Hart C, Gruer L, Bauld L. Does smoking reduction in midlife reduce mortality risk? Results of 2 long-term prospective cohort studies of men and women in Scotland. American Journal of Epidemiology. 2013;178(5):770–9.

29. NICE. Tobacco : harm-reduction approaches to smoking. 2013;(July).

30. McDermott L, Dobson A, Owen N. Smoking reduction and cessation among young adult women: a 7-year prospective analysis. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 2008;10(9):1457–66.

31. Broms U, Korhonen T, Kaprio J. Smoking reduction predicts cessation: longitudinal evidence from the Finnish adult twin cohort. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 2008;10(3):423–7.

32. Falba T, Jofre-Bonet M, Busch S, Duchovny N, Sindelar J. Reduction of quantity smoked predicts future cessation among older smokers. Addiction. 2004;99(1):93–102.

33. Hyland A, Levy DT, Rezaishiraz H, et al. Reduction in amount smoked predicts future cessation. Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors. 2005;19(2):221–5.

Scientists have identified over 5,300 different chemicals in tobacco smoke [11]. The International Agency for Research into Cancer (IARC), the gold standard for establishing the causes of cancer, state that there are more than 70 chemicals in tobacco smoke that have been found to cause cancer in studies involving people or in the laboratory [11]. And many of the other thousands of chemicals are toxic and harmful to your health, including carbon monoxide, hydrogen cyanide and ammonia [1, 34].

In 1994 tobacco companies in the US released a list of 599 different cigarette additives, which included chocolate, vanilla, sugar and liquorice as well as common herbs and spices [35]. Although these don’t make cigarettes any more toxic, they are meant to make cigarettes taste nicer and ensure that smokers want to continue smoking.

Flavoured tobacco, such as menthol or chocolate-flavoured cigarettes, will be banned in Europe from 2016 under the Tobacco Products Directive [36]. Although additives necessary for manufacturing tobacco can continue to be used, including sugar lost during the curing process, tobacco companies will have to do more research into additives with the possibility that those found to be more harmful or addictive could be banned from use [36].

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

34. Hoffmann D, Hoffmann I. The changing cigarette: chemical studies and bioassays. Smoking and Tobacco Control Monograph No 13. 2001:159–191. View resource

35. Doull J, Frawley JP, George WJ, Loomis T, Squire RA, Taylor SL. List of ingredients added to tobacco in the manufacture of cigarettes by 6 major American cigarette companies. 1994. View resource

36. The European Commission. Commission Directive 2014/39/EU.; 2014. View resource

Chemicals found in tobacco smoke can damage DNA [1, 11, 37]. For example, studies have shown that benzo(a)pyrene damages a gene called p53 that normally protects our cells from cancer [37, 38]. While polonium-210 becomes concentrated in hotspots in smokers’ airways, subjecting them to very high doses of high-energy alpha-radiation that damages the DNA of nearby cells [39].

The cocktail of chemicals in tobacco smoke is even more dangerous as a mix. Toxic metals found in tobacco smoke, like cadmium, arsenic, and lead, stop our cells from repairing DNA damage [40]. This worsens the effects of chemicals like benzo(a)pyrene that damage DNA and makes it even more likely that damaged cells will eventually turn cancerous.

Many tobacco poisons disable the cleaning system that our bodies use to remove toxins. Some substances including formaldehyde and acrolein kill cilia, tiny hairs in our airways that help to clear away toxins [37].

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

37. US Surgeon General. How Tobacco Smoke Causes Disease : The Biology and Behavioral Basis for Smoking-Attributable Disease.; 2010.

38. Denissenko MF, Pao A, Tang M, Pfeifer GP. Preferential formation of Benzo(a)pyrene adducts at lung cancer mutational hotspots in p53. Science. 1996;274:430–432. View summary on PubMed

39. Zagà V, Lygidakis C, Chaouachi K, Gattavecchia E. Polonium and lung cancer. Journal of oncology. 2011;2011:860103. View resource

40. Koedrith P, Seo YR. Advances in carcinogenic metal toxicity and potential molecular markers. International journal of molecular sciences. 2011;12(12):9576–95. View resource

Most smokers do not smoke out of choice, but because they are addicted to nicotine [37, 41]. This was highlighted in a report by The Royal College of Physicians into the effects of nicotine [41]. They also compared nicotine to other supposedly ‘harder’ drugs such as heroin and cocaine. They looked at many things including how these drugs cause addiction, how difficult it is to stop using them and how many deaths they caused. The report concluded that nicotine is a highly addictive substance, particularly when people are exposed to it through using tobacco, and that tobacco dependence is at least as serious as addiction to ‘harder’ drugs [41].

People associate smoking with feeling less stressed and anxious, but the evidence suggests this is only because it temporarily relieves the unpleasant symptoms of nicotine withdrawal [37, 41]. If anything, current smokers seem to feel more stressed and anxious than ex-smokers or people who have never smoked [41].

Smokers can also make mental links with abstract things like the smell of cigarettes, objects related to smoking like ashtrays and lighters, and situations in which they usually smoke. These can all act to reinforce the addiction to smoking [37].

References

37. US Surgeon General. How Tobacco Smoke Causes Disease : The Biology and Behavioral Basis for Smoking-Attributable Disease.; 2010.

41. The Tobacco Advisory Group of the Royal College of Physicians. Nicotine addiction in Britain.; 2000.

Current smokers have a higher risk of lung cancer than former smokers or never smokers, whatever type of cigarettes they smoke [1, 11]. There is no difference between the risk of dying from lung cancer for smokers of cigarettes ‘rated’ as medium, low and very low in tar [42]. But smoking unfiltered high tar varieties makes the risk even higher  [1, 11, 42] .

The amounts of tar or nicotine associated with a particular variety of cigarette are based on machine measurements of smoking. But the measurements don’t accurately reflect the amounts actually received by a smoker [1, 34, 37, 43]. Research that measured markers of nicotine and certain cancer-causing chemicals in smokers found that they took in the same amounts whatever the tar rating of the cigarettes they smoked [44]. Smokers change the way they smoke – such as taking bigger or more frequent puffs, blocking filter holes or smoking more cigarettes in total – in order to satisfy their nicotine cravings [1, 11, 37, 43].

In 2003 EU legislation came into force banning tobacco companies from using phrases like ‘light’, ‘mild’ or ‘low-tar’ to describe their products because these could mislead people into believing such products were safer or healthier [45].

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

34. Hoffmann D, Hoffmann I. The changing cigarette: chemical studies and bioassays. Smoking and Tobacco Control Monograph No 13. 2001:159–191. View resource

37. US Surgeon General. How Tobacco Smoke Causes Disease : The Biology and Behavioral Basis for Smoking-Attributable Disease.; 2010.

42. Harris JE, Thun MJ, Mondul AM, Calle EE. Cigarette tar yields in relation to mortality from lung cancer in the cancer prevention study II prospective cohort, 1982-8. BMJ (Clinical research ed.). 2004;328(7431):72. View resource

43. Thun MJ, Burns DM. Health impact of “reduced yield” cigarettes: a critical assessment of the epidemiological evidence. Tobacco Control. 2001;10 Suppl 1(Suppl I):i4–11. View resource

44. Hecht SS, Murphy SE, Carmella SG, et al. Similar Uptake of Lung Carcinogens by Smokers of Regular , Light , and Ultralight Cigarettes Similar Uptake of Lung Carcinogens by Smokers of Regular ,. 2005:693–698.

45. The European Parliament and the Council of the European Union. Directive 2001/37/EC.; 2001. View resource

 

Alcohol has also been shown to be a cause of mouth, oesophageal and liver cancers, among others [11]. And scientists have found that together, the effects of alcohol and tobacco are worse than for either one of them by itself [11, 46-49].

References

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

46. Kuper H, Tzonou a, Kaklamani E, et al. Tobacco smoking, alcohol consumption and their interaction in the causation of hepatocellular carcinoma. International Journal of Cancer. 2000;85(4):498–502. View summary on PubMed

47. Boyle P. European Code Against Cancer and scientific justification: third version (2003). Annals of Oncology. 2003;14(7):973–1005. View resource

48. Hashibe M, Brennan P, Chuang S-C, et al. Interaction between tobacco and alcohol use and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium. Cancer Epidemiology, Biomarkers & Prevention. 2009;18(2):541–50. View resource

49. Turati F, Garavello W, Tramacere I, et al. A Meta-analysis of Alcohol Drinking and Oral and Pharyngeal Cancers: Results from Subgroup Analyses. Alcohol and Alcoholism (Oxford, Oxfordshire). 2012;0(0):1–12. View summary on PubMed

 

There is clear evidence that breathing in other people’s smoke causes cancer in non-smokers [1, 11, 37, 50]. Second-hand smoke, also known as environmental tobacco smoke or passive smoking, exposes people to cancer-causing chemicals [11].

People who have never smoked have their risk of lung cancer increased by around a quarter if they have colleagues who smoke at work or have a spouse who smokes [50-52]. The risk increases the more second-hand smoke they’re exposed to, workers exposed to the highest levels can have their risk of lung cancer doubled [51, 52].

Second-hand smoke can reach high levels in enclosed spaces such as within the home or inside a car [53-57]. Studies have shown that even when you open the windows levels can be dangerously high [53, 55, 57, 58].

Second-hand smoke also causes other health problems in non-smokers including heart disease and respiratory diseases including asthma in children [37, 50, 59]. And it may increase the risk of pharyngeal and laryngeal cancers [10, 11].

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

10. Cogliano VJ, Baan R, Straif K, et al. Preventable exposures associated with human cancers. Journal of the National Cancer Institute. 2011;103(24):1827–39. View summary on PubMed

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

37. US Surgeon General. How Tobacco Smoke Causes Disease : The Biology and Behavioral Basis for Smoking-Attributable Disease.; 2010.

50. Scientific Committee on Tobacco and Health (SCOTH). Secondhand Smoke: Review of evidence since 1998.; 2004.

51. Taylor R, Najafi F, Dobson A. Meta-analysis of studies of passive smoking and lung cancer: effects of study type and continent. International Journal of Epidemiology. 2007;36(5):1048–59. View summary on PubMed

52. Stayner L, Bena J, Sasco AJ, et al. Lung cancer risk and workplace exposure to environmental tobacco smoke. American Journal of Public Health. 2007;97(3):545–51. View resource

53. Blackburn C, Spencer N, Bonas S, Coe C, Dolan A, Moy R. Effect of strategies to reduce exposure of infants to environmental tobacco smoke in the home: cross sectional survey. BMJ (Clinical research ed.). 2003;327(7409):257.

54. Lofroth G. Environmental Tobacco Smoke: Multicomponent Analysis and Room-to-room Distribution in Homes. Tobacco control. 1993;2:222–225.

55. Wakefield M, Banham D, Martin J, Ruffin R, McCaul K, Badcock N. Restrictions on smoking at home and urinary cotinine levels among children with asthma. American journal of preventive medicine. 2000;19(3):188–92.

56. ASH Scotland. Smoking in vehicles : An evidence review. 2013;(April).

57. Semple S, Apsley A, Galea KS, MacCalman L, Friel B, Snelgrove V. Secondhand smoke in cars: assessing children’s potential exposure during typical journey conditions. Tobacco control. 2012;21(6):578–83.

58. Sendzik T, Fong GT, Travers MJ, Hyland A. An experimental investigation of tobacco smoke pollution in cars. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 2009;11(6):627–34.

59. Royal College of Physicians. Passive smoking and children. Image (Rochester, N.Y.); 2010.

 

It’s not just cigarettes which increase the risk of cancer – other ways of smoking tobacco including pipes, cigars, bidis and shisha are also linked with the disease [1, 11, 60, 61]. Reviews of the evidence by the International Agency for Research on Cancer have concluded that smoking cigars, pipes or bidis increases the risk of lung, mouth, throat, voice box, gullet (oesophagus) and stomach cancers [1, 11]. And cigar smoking has also been linked with pancreatic cancer [1, 60, 62]. Shisha smoking has been less well studied but the evidence suggests it is linked to lung cancer and possibly other cancers [63, 64].

Because they think it is healthier, some cigarette smokers switch to smoking a cigar or pipe. But aside from the health risks associated with pipes and cigars, research has also shown that because these people are more likely to inhale the smoke than people who have only ever smoked a cigar or pipe, the switch makes little difference to their chance of dying as a result of smoking [60].

References

1. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004. View resource

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

60. O’Connor RJ. Non-cigarette tobacco products: what have we learnt and where are we headed? Tobacco Control. 2012;21(2):181–190.

61. Akl E a, Gaddam S, Gunukula SK, Honeine R, Jaoude PA, Irani J. The effects of waterpipe tobacco smoking on health outcomes: a systematic review. International Journal of Epidemiology. 2010;39(3):834–57.

62. Bertuccio P, La Vecchia C, Silverman DT, et al. Cigar and pipe smoking, smokeless tobacco use and pancreatic cancer: an analysis from the International Pancreatic Cancer Case-Control Consortium (PanC4). Annals of Oncology. 2011;22(6):1420–6. View resource

63. Dar N a, Bhat G a, Shah I a, et al. Hookah smoking, nass chewing, and oesophageal squamous cell carcinoma in Kashmir, India. British journal of cancer. 2012;107(9):1618–23.

64. Sadjadi A, Derakhshan MH, Yazdanbod A, et al. Neglected role of hookah and opium in gastric carcinogenesis: A cohort study on risk factors and attributable fractions. International Journal of Cancer. 2013;00:1–8.

 

 

There are a wide variety of smokeless tobacco products used around the world [11, 65]. In the UK chewing tobacco, which may be used as part of betel quid, paan or zarda, is popular with South Asian communities. Tobacco can also be chewed or sucked by itself, or taken as snuff.

Smokeless tobacco has been shown to cause mouth, gullet (oesophageal) and pancreatic cancers [11, 66]. Chewing betel quid with tobacco has also been shown to cause cancer of the mouth, upper throat and gullet (oesophagus) [11]. The size of the cancer risks associated with using smokeless tobacco are likely to vary depending on the type of product and the way it’s used [65].

It has been suggested that smokeless tobacco could be used to help people stop using smoking tobacco, and that falling smoking rates in Sweden have been linked to people switching to a type of smokeless tobacco called ‘snus’. But a review of the evidence by the IARC in 2007 concluded that the available evidence does not support these claims [66].

There are many cancer-causing chemicals present in smokeless tobacco, including in ‘snus’ [11, 65, 66]. Studies have shown that these harmful chemicals, such as tobacco-specific nitrosamines (TSNAs), are taken up by people using these products [65].

Smokeless tobacco also contains nicotine, and is therefore addictive [11, 65, 66].

References

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

65. Boffetta P, Hecht S, Gray N, Gupta P, Straif K. Smokeless tobacco and cancer. Lancet Oncology. 2008;9(July):667–675.

66. IARC. Smokeless Tobacco and Some Tobacco-specific N -Nitrosamines. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2007;89. Link

 

Although some users have claimed that e-cigarettes have helped them stop smoking, there is not enough scientific evidence to show whether they are effective, and as safe as current licensed cessation aids (such as nicotine patches) [67-72]. So far there has only been one trial comparing the use of e-cigarettes to another stop smoking aid (patches in this case) [73]. Unfortunately this trial was too small to show a significant difference between the likelihood of quitting [73].

However e-cigarettes are almost certainly far safer than smoking tobacco [74, 75]. E-cigarettes may play a role in helping smokers quit but larger trials are needed as scientific evidence that they really work, to explore how best to use them and to see how they  compare to other methods of quitting [72].

References

67. Etter J-F, Bullen C. Electronic cigarette: users profile, utilization, satisfaction and perceived efficacy. Addiction (Abingdon, England). 2011;106(11):2017–28.

68. Etter J-F, Bullen C. A longitudinal study of electronic cigarette users. Addictive Behaviors. 2013:4–7.

69. Barbeau AM, Burda J, Siegel M. Perceived efficacy of e-cigarettes versus nicotine replacement therapy among successful e-cigarette users: a qualitative approach. Addiction science & clinical practice. 2013;8(1):5.

70. Dockrell M, Morrison R, Bauld L, McNeill A. E-cigarettes: prevalence and attitudes in Great Britain. Nicotine & Tobacco Research. 2013;15(10):1737–44.

71. Caponnetto P, Campagna D, Cibella F, et al. EffiCiency and Safety of an eLectronic cigAreTte (ECLAT) as tobacco cigarettes substitute: a prospective 12-month randomized control design study. PloS one. 2013;8(6):e66317.

72. MHRA Working Group on NCPs. Quality, safety and efficay of unlicensed NCPs. 2013.

73. Bullen C, Howe C, Laugesen M, et al. Electronic cigarettes for smoking cessation : a randomised controlled trial. Baseline. 2013;6736(13):1–9.

74. Burstyn I. Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks. BMC Public Health. 2014;14(1):18.

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