Avoidable Global Cancer Deaths and Total Deaths from Smoking
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ANALYSIS Avoidable global cancer deaths and total deaths from smoking Prabhat Jha Abstract | On the basis of current consumption patterns, approximately 450 million adults will be killed by smoking between 2000 and 2050. At least half of these adults will die between 30 and 69 years of age, losing decades of productive life. Cancer and the total deaths due to smoking have fallen sharply in men in high-income countries but will rise globally unless current smokers, most of whom live in low- and middle-income countries, stop smoking before or during middle age. Tripling the taxes on tobacco could rapidly raise cessation rates and deter the initiation of smoking. Higher taxes, regulations on smoking and information for consumers could avoid at least 115 million smoking-associated deaths in the next few decades, including around 25 million cancer deaths. Tobacco use kills approximately 5–6 million people Epidemiology annually worldwide, accounting for 1 in every 5 male Smoking patterns. This Analysis focuses on the use of deaths and 1 in 20 female deaths in individuals over 30 smoked tobacco because it is more common — it accounts years of age1–4. On the basis of current smoking patterns, for approximately 85% of all tobacco produced world- the number of annual deaths due to smoking will rise to wide7 — and because inhaled tobacco causes more disease around 10 million by 2030, and there will be approxi- and more diverse types of disease than does oral tobacco mately 1 billion deaths due to smoking in the twenty-first use8–10. Similarly, active smoking is more hazardous century, of which over 70% will be in low- and middle- than exposure to second-hand smoke8,9,11, although income countries outside north America and Europe1,5. second-hand smoke substantially contributes to illness12. By contrast, 100 million deaths due to smoking occurred Approximately 1.1 billion people worldwide smoke, of in the twentieth century, of which nearly 70% occurred in whom over 80% reside in low- and middle-income coun- high-income countries and in the former socialist econ- tries. In these countries, around 49% of men and 8% of omies of Europe6. Unless there is widespread cessation women above the age of 15 years smoke, in contrast to of smoking, approximately 450 million deaths will have 37% of men and 21% of women in high-income coun- occurred as a result of smoking by 2050 and most of tries13. Over 60% of all smokers live in just 10 countries these will occur in current smokers. An additional 500 (listed in order of highest numbers of smokers): China, million tobacco-related deaths will occur in the second India, Indonesia, Russian Federation, the United States, half of the century, mostly in future smokers (FIG. 1). Japan, Brazil, Bangladesh, Germany and Turkey4. This Analysis argues that widespread use of a few The consumption per adult per day (the number powerful price, information and regulation interventions of cigarettes smoked per day, divided by the population of could avoid a large proportion of the expected 450 mil- smokers and non-smokers) has decreased by over 50% lion deaths due to smoking over the next few decades. in the past 2–3 decades in the United States, the United I first present the epidemiology of smoking-associated Kingdom, Canada, France and other high-income coun- disease and explain the importance of the long delay tries14. By contrast, the prevalence of smoking in males has Centre for Global Health Research, St. Michael’s between the onset of smoking and mortality from can- risen sharply in many low- and middle-income countries, Hospital, University of cer and other diseases for future disease risks and for such as China and Indonesia (FIG. 2). Smoking in India is Toronto, Toronto the benefits of cessation. This is followed by a discussion mostly in the form of bidi, which are smaller than ciga- M5C 1N8, Canada. of the effectiveness of interventions to rapidly increase rettes and typically contain only around one-quarter as e-mail: cessation rates in low- and middle-income countries. much tobacco, which is wrapped in the leaf of another [email protected] doi:10.1038/nrc2703 Finally, I present a mathematical projection model that plant. Smoking trends for Indian males have been sta- Published online describes the impact of interventions on cancer and total ble, although recent increases in cigarette smoking in 20 August 2009 mortality in the 1.1 billion current smokers worldwide. young men in urban areas have been reported15 but not NATURE REVIEWS | CANCER VOLUME 9 | SEPTEMBER 2009 | 655 © 2009 Macmillan Publishers Limited. All rights reserved ANALYSIS 27 At a glance who smoked than in those who did not . The differences in the risk of death between smokers and non-smokers • Currently, smoking causes approximately 5–6 million deaths per year, including 31% became more extreme in 1981–2001 than they were in and 6% of all cancer deaths in middle-aged men and women, respectively. The 1951–1980 (REF. 28). Those who smoked over a prolonged proportions of male cancer and total deaths due to smoking are falling in period lost around 10 years of life compared with non- high-income countries but rising in low- and middle-income countries. smokers. Most, but not all, of the absolute excess in death • Cessation by current smokers is the only practical way to avoid a substantial from all causes among smokers was due to smoking, as proportion of tobacco deaths worldwide before 2050. there were no material differences between smokers, • Cessation before middle age avoids more than 90% of the lung cancer mortality non-smokers and ex-smokers in education, drinking and attributable to smoking and markedly reduces the risks of death from other diseases. obesity. Similarly, the main increase in cigarette smoking Although cessation has become common in high-income countries, it is still rare in most low- and middle-income countries. in the United States occurred in 1920–1940, and consump- tion peaked at approximately 10 cigarettes per adult per • Countries such as France that have aggressively used higher taxes to curb smoking (REFS 14,29) have reduced consumption much faster than countries that have not aggressively day around 1960 . However, the rates of lung increased tobacco taxation. cancer, almost all of which are due to smoking, peaked only around 30 years later6,29–31 (FIG. 2). • In low- and middle-income countries, a 10% higher tobacco price reduces consumption by around 8%, which is twice the effect seen in high-income countries. Health information, counter-advertising, restrictions on smoking and cessation Effects of cessation on lung cancer and total deaths. therapies are also highly effective at reducing smoking. Widespread cessation of smoking in high-income coun- • A 70% higher street price of cigarettes (corresponding to around a 2–3-fold higher tries has afforded the opportunity to study the impact tax) would avoid 115 million deaths or one-quarter of expected tobacco deaths over of stopping smoking at various ages on the risk of death the next few decades. Of the avoided deaths, approximately 25 million would be from from tobacco-attributable diseases. United Kingdom cancer and 50 million from vascular disease. doctors who stopped smoking before the onset of major disease avoided most of the hazards of smoking. Compared with individuals who continued smoking, the yet confirmed16. A notable exception to the increases of life expectancy gained by stopping smoking around 60, smokers in low- and middle-income countries is Brazil, 50, 40 or 30 years of age was approximately 3, 6, 9 years which has recorded decreases in the prevalence of adult or almost the full 10 years, respectively27. smokers17. Cessation before middle age (defined as around 30 years) avoids more than 90% of the lung cancer mor- Smoking cessation. The smoking prevalence in a popu- tality attributable to smoking, and individuals who stop lation comprises the current smokers, ex-smokers and smoking show a similar pattern of survival to that of indi- individuals who have never smoked. The prevalence of viduals who have never smoked. In the United Kingdom, ex-smokers is a good measure of cessation at a popu- among those who stopped smoking, the risk of lung can- lation level1,13. Cessation, together with an increasing cer fell steeply with time since cessation18; for men who proportion of individuals who have never smoked, has stopped at ages 50, 40 and 30 years, the cumulative risks reduced the adult (aged >30 years) smoking prevalence of lung cancer mortality by age 75 years were 6%, 3% and in the United Kingdom between 1950 and 2005 from 70% 2%, respectively, in contrast to the risk of 16% for indi- to 25% in men and 40% to 20% in women14. There are viduals who continued to smoke. Similar reductions in now twice as many ex-smokers as smokers in the United the risk of death from lung cancer have occurred in the Kingdom who are currently aged 50 years or over18. United States in men (FIG. 3) and women29. The absolute Similar increases in cessation have been reported in most reduction in mortality due to cessation of smoking might high-income countries13,19. By contrast, the prevalence of be even greater for other diseases, particularly vascular male ex-smokers in most low- and middle-income coun- diseases, than for lung cancer in the first decade or two tries is low: <10% in China20 and Vietnam21, and <2% after stopping smoking27. in India22,23. Even these low figures might be falsely high because they include people who have stopped smoking Current and future disease risks from smoking as a result of being too ill to continue or as a result of the Currently, approximately 70% of the 40 million deaths diagnosis of early symptoms of illnesses attributable to among adults over the age of 30 years worldwide are smoking tobacco24, such as respiratory disease.