The Burden of Tobacco Use: A Half Century of Progress and Challenges, Exams of Public Health

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The Health Consequences

of Smoking—50 Years of Progress

A Report of the Surgeon General

Executive Summary

U.S. Department of Health and Human Services

Suggested Citation U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. For more information For more information about the Surgeon General’s report, visit www.surgeongeneral.gov. To download copies of this document, go to www.cdc.gov/tobacco. To order copies of this document, go to www.cdc.gov/tobacco and click on Publications Catalog or call 1-800-CDC-INFO (1-800-232-4636); TTY: 1-888-232-6348. Use of trade names is for identification only and does not constitute endorsement by the U.S. Department of Health and Human Services. Any recommendations expressed by non-governmental individuals or organizations do not necessarily represent the views or opinions of the U.S. Department of Health and Human Services.

Message from Kathleen Sebelius

Secretary of Health and Human Services Fifty years after the release of the first Surgeon General’s report warning of the health hazards of smoking, we have learned how to end the tobacco epidemic. Over the past five decades, scientists, researchers and policy makers have determined what works, and what steps must be taken if we truly want to bring to a close one of our nation’s most tragic battles—one that has killed ten times the num- ber of Americans who died in all of our nation’s wars combined. In the United States, successes in tobacco control have more than halved smoking rates since the 1964 landmark Surgeon General’s report came out. Americans’ collective view of smoking has been transformed from an accepted national pastime to a discouraged threat to individual and public health. Strong policies have largely driven cigarette smoking out of public view and public air space. Thanks to smokefree laws, no longer is smoking allowed on airplanes or in a growing number of restaurants, bars, college campuses and government buildings. Evidence in this new report shows tobacco’s continued, immense burden to our nation—and how essential ending the tobacco epidemic is to our work to increase the life expectancy and quality of life of all Americans. This year alone, nearly one-half million adults will still die prematurely because of smok- ing. Annually, the total economic costs due to tobacco are now over $289 billion. And if we continue on our current trajectory, 5.6 million children alive today who are younger than 18 years of age will die prematurely as a result of smoking. I believe that we can make the next generation tobacco-free. And I am extremely proud of the Obama Administration’s tobacco-control record. For example, the 2009 Children’s Health Insurance Program Reauthorization Act included an unprecedented $0.62 tax increase that raised the federal excise tax to $1.01 per pack of cigarettes; we know that increasing the cost of cigarettes is one of the most powerful interventions we can make to prevent smoking and reduce prevalence. Building on this knowledge, the President’s Fiscal Year 2014 Budget includes a $0.94 per pack Federal tobacco tax increase. For the first time in history, the 2009 Family Smoking Prevention and Tobacco Control Act ( Tobacco Control Act) g ave the U.S. Food and Drug Administration comprehensive authority to regu- late tobacco products, which will play a critical role in reducing the harm caused by these products. The Tobacco Control Act also provided for user fees to be paid by tobacco manufacturers that can sup- port sustained public education media campaigns targeting youth prevention and cessation. The 2010 Affordable Care Act (ACA) expands access to smoking cessation services and now requires most insur- ance companies to cover cessation treatments. The Affordable Care Act’s Public Health and Prevention Fund is supporting innovative and effective community-based programs as well as public education campaigns promoting prevention and helping people to quit. All of these tobacco control interventions are known to reduce tobacco use and, as a result, tobacco’s extraordinary toll of death and disease. But in order to free the next generation from these burdens, we must redouble our tobacco control efforts and enlist nongovernmental partners—and society as a whole—to share in this responsibility. Ending the devastation of tobacco-related illness and death is not in the jurisdiction of any one entity. We must all share in this most worthwhile effort to end the tobacco epidemic.

Message from Howard Koh

Assistant Secretary for Health The nation stands poised at the crossroads of tobacco control. On one hand, we can celebrate tremendous progress 50 years after the landmark 1964 Surgeon General’s report: Smoking and Health. Adult smoking rates have fallen from about 43% (1965) to about 18% today. Mortality rates from lung cancer, the leading cause of cancer death in this country, are declining. Most smokers visiting health care settings are now routinely asked and advised about tobacco use. On the other hand, cigarette smoking remains the chief preventable killer in America, with more than 40 million Americans caught in a web of tobacco dependence. Each day, more than 3,200 youth (younger than 18 years of age) smoke their first cigarette and another 2,100 youth and young adults who are occasional smokers progress to become daily smokers. Furthermore, the range of emerging tobacco products complicates the current public health landscape. In this context, the 50th Anniversary of the Surgeon General’s report prompts us to pause and ask why this addiction persists when proven interventions can eliminate it. Of great concern, too many in our nation assume that past success in tobacco control guarantees future progress; nothing can be further from the truth. To rejuvenate and reinvigorate national efforts, in 2010, the U.S. Department of Health and Human Services unveiled its first ever strategic plan for tobacco control. Ending the Tobacco Epidemic: A Tobacco Control Strategic Action Plan provides a critical framework to guide efforts to rapidly drop prevalence rates of smoking among youth and adults. A major foundation and pillar of the plan is to encourage and promote leadership throughout all sectors of society. Now, this current 2014 Surgeon General’s report can accelerate that leadership to fully implement the life-saving prevention that can make the next generation free of tobacco-related death and disease. We have many tools that we know work. A comprehensive public policy approach emphasizing mass media campaigns to encourage prevention and quit attempts, smokefree policies, restrictions on youth access to tobacco products, and price increases can collectively drive further meaningful reduc- tions in tobacco use. Furthermore, we can accelerate progress through full commitment to clinical and public health advances; including the widespread use of telephone quit lines and science-based counseling and medications for tobacco users. Promoting progress today also requires recognizing that tobacco use has evolved from being an equal-opportunity killer to one threatening the most vulnerable members of our society. We must confront, and reverse, the tragically higher tobacco use rates that threaten persons of low socioeconomic status, sexual minorities, high school dropouts, some racial/ ethnic minority groups, and those living with mental illness and substance use disorders. Of all the accomplishments of the 20th century, historians rank the 1964 Surgeon General’s report as one of the seminal public health achievements of our time. Armed with both science and resolve, we can continue to honor the legacy of the report by completing the work it began in the last century. The current 2014 Surgeon General’s report represents a national vision for getting the job done. With strategy, commitment, and action, our nation can leave the crossroads and move forward to end the tobacco epidemic once and for all.

ii While we have made tremendous progress over the past 50 years, sustained and comprehensive efforts are needed to prevent more people from having to suffer the pain, disability, disfigurement, and death that smoking causes. Most Americans who have ever smoked have already quit, and most smokers who still smoke want to quit. If we continue to implement tobacco prevention and cessation strategies that have proven effective in reducing tobacco use, people throughout our country will live longer, healthier, more productive lives. Thomas R. Frieden, M.D., M.P.H. Director Centers for Disease Control and Prevention

iii

Preface

from the Acting Surgeon General, U.S. Department of Health and Human Services On January 11, 1964, Luther L. Terry, M.D., the 9th Surgeon General of the United States, released the first report on the health consequences of smoking: Smoking and Health: Report of the Advisory Committee of the Surgeon General of the Public Health Service. That report marked a major step to reduce the adverse impact of tobacco use on health worldwide. Over the past 50 years, 31 Surgeon General’s reports have utilized the best available evidence to expand our understanding of the health consequences of smoking and involuntary exposure to tobacco smoke. The conclusions from these reports have evolved from a few causal associations in 1964 to a robust body of evidence documenting the health consequences from both active smoking and exposure to secondhand smoke across a range of diseases and organ systems. The 2004 report concluded that smoking affects nearly every organ of the body, and the evidence in this report provides even more support for that finding. A half century after the release of the first report, we continue to add to the long list of diseases caused by tobacco use and exposure to tobacco smoke. This report finds that active smoking is now causally associated with age-related macular degeneration, diabetes, colorectal cancer, liver cancer, adverse health outcomes in cancer patients and survivors, tuberculosis, erectile dysfunction, orofacial clefts in infants, ectopic pregnancy, rheumatoid arthritis, inflammation, and impaired immune function. In addition, exposure to secondhand smoke has now been causally associated with an increased risk for stroke. Smoking remains the leading preventable cause of premature disease and death in the United States. The science contained in this and prior Surgeon General’s reports provide all the information we need to save future generations from the burden of premature disease caused by tobacco use. How- ever, evidence-based interventions that encourage quitting and prevent youth smoking continue to be underutilized. This report strengthens our resolve to work together to accelerate and sustain what works—such as hard-hitting media campaigns, smokefree air policies, optimal tobacco excise taxes, barrier-free cessation treatment, and comprehensive statewide tobacco control programs funded at CDC-recommended levels. At the same time, we will explore “end game” strategies that support the goal of eliminating tobacco smoking, including greater restrictions on sales. It is my sincere hope that 50 years from now we won’t need another Surgeon General’s report on smoking and health, because tobacco-related disease and death will be a thing of the past. Working together, we can make that vision a reality. Boris D. Lushniak, M.D., M.P.H. Rear Admiral, U.S. Public Health Service Acting Surgeon General U.S. Department of Health and Human Services

The Health Consequences of Smoking—50 Years of Progress Executive Summary 1 Overview other conditions caused by parental smoking, particularly smoking by the mother. Table 1 Premature deaths caused by smoking and exposure to secondhand smoke, 1965– Cause of death Total Smoking-related cancers 6,587, Cardiovascular and metabolic diseases 7,787, Pulmonary diseases 3,804, Conditions related to pregnancy and birth 108, Residential fires 86, Lung cancers caused by exposure to secondhand smoke 263, Coronary heart disease caused by exposure to secondhand smoke 2,194, Total 20,830, Source: Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, unpublished data. As these figures illustrate, the harms caused by the historic patterns of tobacco use in the United States, and especially by cigarette smoking, are staggering. More than 10 times as many U.S. citizens have died prematurely from cigarette smoking than have died in all the wars fought by the United States during its history. Study after study has confirmed the magnitude of the harm caused to the human body by exposure to toxicants and carcinogens found in tobacco smoke. Since 1964, the 31 previous Sur- geon General’s reports have chronicled a still growing but already conclusive body of evidence about the adverse impact of tobacco use on human cells and organs and on overall health. Health statistics show that all populations are affected. Previous Surgeon General’s reports have tracked the evolution of cigarettes into the current highly engi- neered, addictive, and deadly products containing thou- sands of chemicals that are harmful in themselves, but the burning of tobacco produces the complex chemical mixture of more than 7,000 compounds that cause a wide range of diseases and premature deaths as a result (U.S. Department of Health and Human Services [USDHHS] 2010). Although the prevalence of smoking has declined significantly over the past one-half century, the risks for smoking-related disease and mortality have not. In fact, today’s cigarette smokers—both men and women—have a much higher risk for lung cancer and chronic obstructive pulmonary disease (COPD) than smokers in 1964, despite smoking fewer cigarettes (see Chapters 6, 7, and 11, and Figure 12.2 and Figure 13.16). The 2004 Surgeon General’s report showed that smoking impacts nearly every organ of the body (USD- HHS 2004). The 2006 report concluded that the scientific evidence indicates that there is no risk-free level of expo- sure to secondhand smoke (USDHHS 2006). The new evi- dence in this report provides still more support for these conclusions. Fifty years after the first report in 1964, it is striking that the scientific evidence in this report expands the list of diseases and other adverse health effects caused by smoking and exposure of nonsmokers to tobacco smoke. Figures 1.1A and 1.1B highlight these new find- ings and show that the disease risks are even greater than presented in previous reports. These new findings include:

• Liver cancer and colorectal cancer are added to the long list of cancers caused by smoking; For the United States, the epidemic of smoking- caused disease in the twentieth century ranks among the greatest public health catastrophes of the century, while the decline of smoking consequent to tobacco control is surely one of public health’s greatest successes. How- ever, the current rate of progress in tobacco control is not fast enough, and much more needs to be done to end the tobacco epidemic. Unacceptably high levels of smoking- attributable disease and death, and the associated costs, will persist for decades without changes in our approach to slowing and even ending the epidemic. If smoking persists at the current rate among young adults in this country, 5.6 million of today’s Americans younger than 18 years of age are projected to die prematurely from a smoking-related illness (Chapter 12). More than 20 million Americans have died as a result of smoking since the first Surgeon General’s report on smoking and health was released in 1964 (Table 1) (Chapter 12). Most were adults with a history of smoking, but nearly 2.5 million were nonsmokers who died from heart disease or lung cancer caused by exposure to sec- ondhand smoke. Another 100,000 were babies who died of sudden infant death syndrome (often referred to as SIDS) or complications from prematurity, low birth weight, or

Surgeon General’s Report 2 Executive Summary

• Exposure to secondhand smoke is a cause of stroke;
• Smoking increases the risk of dying from cancer and other diseases in cancer patients and survivors;
• Smoking is a cause of diabetes mellitus; and
• Smoking causes general adverse effects on the body including inflammation and it impairs immune function. Smoking is a cause of rheumatoid arthri- tis. Figure 1A The health consequences causally linked to smoking Source: USDHHS 2004, 2006, 2012. Note: The condition in red is a new disease that has been causally linked to smoking in this report. Progress has been made in tobacco control. During the 50 years since the 1964 report, approaches have moved from single measures, such as small text-only pack warn- ings, to implementing comprehensive control programs, including indoor smoking bans, support for cessation, restrictions on advertising and promotion, media cam- paigns, and tax hikes to raise prices (Chapters 2 and 14). Smoking rates have declined, as have mortality rates for some diseases caused by smoking, such as heart disease and lung cancer for which smoking is the major cause. Nonetheless, between 2005–2009, smoking was responsible for more than 480,000 premature deaths annually among Americans 35 years of age and older (Chapter 12). More than 87% of lung cancer deaths, 61% of all pulmonary disease deaths, and 32% of all deaths from coronary heart disease were attributable to smoking and exposure to secondhand smoke. Additionally, if cur- rent trends continue 5.6 million U.S. youth who are cur- rently younger than 18 years of age will die prematurely during adulthood from their smoking (Chapter 12).

Surgeon General’s Report 4 Executive Summary Major Conclusions from the Report

6. In addition to causing multiple diseases, cigarette smoking has many adverse effects on the body, such as causing inflammation and impairing immune function.
7. Although cigarette smoking has declined signifi- cantly since 1964, very large disparities in tobacco use remain across groups defined by race, ethnicity, edu- cational level, and socioeconomic status and across regions of the country.
8. Since the 1964 Surgeon General’s report, compre- hensive tobacco control programs and policies have been proven effective for controlling tobacco use. Further gains can be made with the full, forceful, and sustained use of these measures.
9. The burden of death and disease from tobacco use in the United States is overwhelmingly caused by ciga- rettes and other combusted tobacco products; rapid elimination of their use will dramatically reduce this burden.
10. For 50 years the Surgeon General’s reports on smok- ing and health have provided a critical scientific foun- dation for public health action directed at reducing tobacco use and preventing tobacco-related disease and premature death.
11. The century-long epidemic of cigarette smoking has caused an enormous avoidable public health tragedy. Since the first Surgeon General’s report in 1964 more than 20 million premature deaths can be attributed to cigarette smoking.
12. The tobacco epidemic was initiated and has been sustained by the aggressive strategies of the tobacco industry, which has deliberately misled the public on the risks of smoking cigarettes.
13. Since the 1964 Surgeon General’s report, cigarette smoking has been causally linked to diseases of nearly all organs of the body, to diminished health status, and to harm to the fetus. Even 50 years after the first Surgeon General’s report, research continues to newly identify diseases caused by smoking, including such common diseases as diabetes mellitus, rheuma- toid arthritis, and colorectal cancer.
14. Exposure to secondhand tobacco smoke has been causally linked to cancer, respiratory, and cardiovas- cular diseases, and to adverse effects on the health of infants and children.
15. The disease risks from smoking by women have risen sharply over the last 50 years and are now equal to those for men for lung cancer, chronic obstructive pulmonary disease, and cardiovascular diseases. The 2014 Surgeon General’s report is presented in three sections: Section 1: Historical Perspective, Overview, and Conclusions; Section 2: The Health Consequences of Active and Passive Smoking: The Evidence in 2014; and Section 3: Tracking and Ending the Epidemic. The following is a summary of the contents of each section.

The Health Consequences of Smoking—50 Years of Progress Executive Summary 5 Section 1: Historical Perspective, Overview, and Conclusions than others. In fact, rates of smoking among women actu- ally increased in the years following the first Surgeon General’s report. During the decades that followed, however, a num- ber of local, state, and federal laws and policies addressed tobacco product marketing and advertising, labeling and packaging, youth access, and exposure to secondhand smoke. Social norms that had made smoking acceptable everywhere began to change as a grassroots movement aimed at protecting nonsmokers emerged. Surgeon Gen- eral’s reports on the impact of tobacco use on specific populations, the changing cigarette, nicotine addiction, specific smoking-related diseases, and secondhand smoke gave impetus to a steady movement away from smoking as an acceptable social norm. The prevalence of smoking among adults is now less than one-half of what it was in 1964, and the prevalence among youth is less than one- half. A 2011 Gallup poll reported that for the first time, a majority of Americans supported a ban on smoking in all public places (Newport 2011). The ongoing story of tobacco use covered in this Surgeon General’s report illustrates the complexity and dynamic nature of the issue. This report examines smok- ing from a public health standpoint; as a cultural and social phenomenon; as an extension of the tobacco indus- try’s aggressive and fraudulent campaigns to mislead the public on health hazards; and from legal, policy, and pub- lic education perspectives. When Dr. Luther L. Terry released the first Surgeon General’s report on smoking and health in January 1964, few could have anticipated the long-term impact it would have on this nation’s health. The report reviewed more than 7,000 research articles related to smoking and dis- ease—the evidence considered dated to the early twenti- eth century but most came from the wave of research that started at mid-century. The initial report concluded that smoking was associated with higher all-cause mortality rates among men, was a cause of lung cancer and laryn- geal cancer in men, was a probable cause of lung cancer in women, and was the most important cause of bronchi- tis (U.S. Department of Health, Education, and Welfare 1964). News coverage of the report was extensive, and the release of the report was ranked among the top news sto- ries of the twentieth century ( USA Today 1999). Nonetheless, public attitudes about smoking and its adverse health effects were slow to change, and smoking declined slowly after the report. In 1964, more than one- half of men and nearly one-third of women were regular smokers; it took approximately 15 years for rates of smok- ing among men to drop by one-quarter or more (Chapter 2). The scientific evidence helped to launch public health campaigns about the dangers of smoking. The tobacco industry attempted to counter these campaigns through aggressive advertising. It used a variety of tactics to cre- ate doubt about the findings on smoking and health and launched marketing strategies that obscured the dangers of smoking by implying that certain cigarettes were safer Section 2: The Health Consequences of Active and Passive Smoking: The Evidence in 2014 1988). That conclusion has been repeatedly reaffirmed in subsequent reports, and nicotine addiction figures centrally in initiation and in the difficulty of cessation (USDHHS 2010, 2012). Additionally, nicotine is a pharma- cologically active agent that has acute toxicity and that readily enters the body and is distributed throughout. Beyond causing addiction, it activates multiple biologic pathways that are relevant to fetal growth and develop- ment, immune function, the cardiovascular system, the central nervous system, and carcinogenesis. Nicotine exposure during fetal development, a critical window Since 1964, the evidence on smoking and health has expanded greatly; the list of adverse consequences of tobacco smoking has lengthened progressively; and since the 1970s, scientific research has linked the inhalation of secondhand smoke by nonsmokers to specific diseases and other adverse effects. Even in this report, a half-century following the first report, the evidence has been found sufficient to infer further causal associations of active and passive smoking with disease. Nicotine and Addiction: Nicotine was found to be addicting in the 1988 Surgeon General’s report (USDHHS

The Health Consequences of Smoking—50 Years of Progress Executive Summary 7 and other coronary events among people younger than 65 years of age, and evidence suggests that there could be a relationship between such laws and policies and a reduc- tion in cerebrovascular events. Diabetes: Previous Surgeon General’s reports have found that smoking complicates the treatment of diabetes and that smokers who have been diagnosed with diabetes are at a higher risk for kidney disease, blindness, and circu- latory complications leading to amputations. This report concludes that smoking is a cause of type 2 diabetes mel- litus, and that the risk of developing diabetes is 30–40% higher for active smokers than nonsmokers (Chapter 10). Furthermore, the risk of developing diabetes increases as the number of cigarettes smoked grows. Immune and autoimmune disorders: This report finds that smoking is a cause of general adverse effects on the body, including systemic inflammation and impaired immune function (Chapter 10). One result of this altered immunity is increased risk for pulmonary infections among smokers. For example, risks for Mycobacterium tuberculosis and for death from tuberculosis disease are higher for smokers than nonsmokers (Chapter 7). Addi- tionally, smoking is known to compromise the equi- librium of the immune system, increasing the risk for several immune and autoimmune disorders. This report finds that smoking is a cause of rheumatoid arthritis, and that smoking interferes with the effectiveness of certain treatments for rheumatoid arthritis (Chapter 10). Reproductive effects: Several additional adverse reproductive effects are now found to be attributable to smoking (Chapter 9). One is ectopic pregnancy, in which the embryo implants in the Fallopian tube or elsewhere outside the uterus. Ectopic pregnancy is very rarely a sur- vivable condition for the fetus and is a potentially fatal condition for the mother. This report finds that mater- nal smoking during early pregnancy is causal for orofa- cial clefts in infants, and evidence suggests that smoking could be associated with certain other birth defects. This report also finds that the evidence is now sufficient to con- clude that there is a causal relationship between smoking and erectile dysfunction in men. Eye disease: The retina is a delicate, light-sensitive tissue that lines the inside of the eye. The macula is the most sensitive part of the retina and is the part of the eye that supplies sharp vision. Age-related macular degenera- tion (AMD) gradually destroys the macula and can ulti- mately lead to loss of vision in the center of the eye. This report finds that smoking is a cause of AMD (Chapter 10). Evidence in the report also suggests that quitting smok- ing may reduce the risk for AMD, but the reduced risk may not appear for 20 or more years after smoking cessation. General health: Smokers have long been known to suffer from poorer general health than nonsmokers, beginning at an early age and extending throughout adult life (Chapter 11). Although emphasis has been given to smoking as a cause of specific and avoidable diseases, it is a powerful cause of ill-health generally. These health defi- cits not only reduce the quality of life of smokers but also affect their participation in the workplace and increase their costs to the health care system. All-cause mortality: The evidence in this report reaf- firms that smoking is a major cause of premature death (Chapter 11). During the past 50 years, as generations of men and women who began smoking in adolescence and continued to smoke into middle and older ages have been stricken with the health consequences of lifetime smoking, the relative risk for all-cause mortality associ- ated with current cigarette smoking has increased. The age-standardized relative risk, comparing the all-cause death rate in current smokers to that of never smokers, has more than doubled in men and more than tripled in women during the years since the release of the first Sur- geon General’s report on smoking and health. The lives of smokers are cut short by the development of the many diseases caused by smoking and by their greater risk of dying from common health events, such as complications of routine surgeries and pneumonia. Smoking shortens life far more than most other risk factors for early mortal- ity; smokers are estimated to lose more than a decade of life. Smoking cessation by 40 years of age reduces that loss approximately 90%. Even stopping by about 60 years of age reduces that loss approximately 40%. However, reduc- ing the number of cigarettes smoked per day is much less effective than quitting entirely for avoiding the risks of premature death from all smoking-related causes of death. Much of this 50th anniversary Surgeon General’s report is devoted to examining evidence on the myriad health effects, avoidable diseases, and all-cause mortal- ity from smoking. Chapters highlight findings on specific health topics from previous Surgeon General’s reports in addition to presenting current information. The follow- ing are chapter-specific conclusions related to the health effects of smoking from Section 2 of the report.

Chapter 5: Nicotine

1. The evidence is sufficient to infer that at high-enough doses nicotine has acute toxicity.
2. The evidence is sufficient to infer that nicotine acti- vates multiple biological pathways through which smoking increases risk for disease.

Surgeon General’s Report 8 Executive Summary

3. The evidence is sufficient to infer that nicotine expo- sure during fetal development, a critical window for brain development, has lasting adverse consequences for brain development.
4. The evidence is sufficient to infer that nicotine adversely affects maternal and fetal health dur- ing pregnancy, contributing to multiple adverse out- comes such as preterm delivery and stillbirth.
5. The evidence is suggestive that nicotine exposure during adolescence, a critical window for brain devel- opment, may have lasting adverse consequences for brain development.
6. The evidence is inadequate to infer the presence or absence of a causal relationship between exposure to nicotine and risk for cancer.

Chapter 6: Cancer

Lung Cancer

1. The evidence is sufficient to conclude that the risk of developing adenocarcinoma of the lung from ciga- rette smoking has increased since the 1960s.
2. The evidence is sufficient to conclude that the increased risk of adenocarcinoma of the lung in smokers results from changes in the design and com- position of cigarettes since the 1950s.
3. The evidence is not sufficient to specify which design changes are responsible for the increased risk of ade- nocarcinoma, but there is suggestive evidence that ventilated filters and increased levels of tobacco-spe- cific nitrosamines have played a role.
4. The evidence shows that the decline of squamous cell carcinoma follows the trend of declining smoking prevalence. Liver Cancer
5. The evidence is sufficient to infer a causal relation- ship between smoking and hepatocellular carcinoma. Colorectal Cancer
6. The evidence is sufficient to infer a causal relation- ship between smoking and colorectal adenomatous polyps and colorectal cancer. Prostate Cancer 1. The evidence is suggestive of no causal relationship between smoking and the risk of incident prostate cancer. 2. The evidence is suggestive of a higher risk of death from prostate cancer in smokers than in nonsmokers. 3. In men who have prostate cancer, the evidence is sug- gestive of a higher risk of advanced-stage disease and less-well-differentiated cancer in smokers than in nonsmokers, and—independent of stage and histo- logic grade—a higher risk of disease progression. Breast Cancer 1. The evidence is sufficient to identify mechanisms by which cigarette smoking may cause breast cancer. 2. The evidence is suggestive but not sufficient to infer a causal relationship between tobacco smoke and breast cancer. 3. The evidence is suggestive but not sufficient to infer a causal relationship between active smoking and breast cancer. 4. The evidence is suggestive but not sufficient to infer a causal relationship between exposure to secondhand tobacco smoke and breast cancer. Adverse Health Outcomes in Cancer Patients and Survivors 1. In cancer patients and survivors, the evidence is suf- ficient to infer a causal relationship between ciga- rette smoking and adverse health outcomes. Quitting smoking improves the prognosis of cancer patients. 2. In cancer patients and survivors, the evidence is suf- ficient to infer a causal relationship between cigarette smoking and increased all-cause mortality and can- cer-specific mortality. 3. In cancer patients and survivors, the evidence is suf- ficient to infer a causal relationship between cigarette smoking and increased risk for second primary can- cers known to be caused by cigarette smoking, such as lung cancer.