TOBACCO SMOKING AND LONGEVITY

Chance, ignorance, and the paradoxes of cancer: Richard Peto on developing preventative strategies under uncertainty

During the early 1980s both cancer biology and epidemiological methods were being transformed. In 1984 the leading cancer epidemiologist Richard Peto - who, in 1981, had published the landmark Causes of Cancer with Richard Doll - wrote a short chapter on "The need for ignorance in cancer research", in which the worlds of epidemiology and speculative Darwinian biology met. His reflections on how evolutionary theory related to cancer have become known as "Peto's paradox", whilst his articulation of "black box epidemiology" provided the logic of subsequent practice in the field. We reprint this sparkling and prescient example of biologically-informed epidemiological theorising at its best in this issue of the European Journal of Epidemiology, together with four commentaries that focus on different aspects of its rich content. Here were provide some contextual background to the 1984 chapter, and our own speculations regarding various paradoxes in cancer epidemiology. We suggest that one reason for the relative lack of progress in indentifying novel modifiable causes of cancer over the last 40 years may reflect such exposures being ubiquitous within environments, and discuss the lessons for epidemiology that would follow from this.

Advocacy for Global Tobacco Control and Child Health

Tobacco and secondhand smoke remain leading threats to public health. Evidence since the 1950s has shown that the tobacco industry has acted in bad faith to deceive the public about the health effects of smoking. They have specifically targeted vulnerable populations including children and adolescents with various-and often misleading-marketing efforts and promotions. The increased popularity and weak regulation of electronic cigarettes have created a new generation of smokers who mistakenly believe they are "safer" from harm. Continued research, advocacy, and government action are needed to protect public health. Public health advocates must know the evidence, build coalitions, and prepare for industry countermeasures. Persistence is key, but public health efforts have successfully decreased tobacco-related deaths.

Evaluating community-driven cardiovascular health policy changes in the United States using agent-based modeling

Comprehensive smoke-free policy is a strategy to prevent cardiovascular disease (CVD) at a population-level; however, evaluating their long-term outcomes is difficult. This study used an agent-based model to estimate long-term impacts of a comprehensive smoke-free policy, as it was implemented in two communities, Arlington and Mesquite, Texas. The model predicted the percentage of myocardial infarction (MI), stroke, and diabetes in the population 10 and 20 years following policy adoption. In Arlington, the percentage of the population with these conditions each decreased by approximately 0.5% over 20 years; in Mesquite, the percentage of the population with diabetes, myocardial infarction (MI), and stroke decreased by 1.1%, 0.6%, and 0.3%, respectively, after 20 years. The results were statistically significant (p < 0.001). As an evaluation strategy, agent-based modeling can help researchers and practitioners estimate the potential long-term effects of policies and garner intervention support for implementation.

Association of cigarette smoking with retinal thickness and vascular structure in an elderly Chinese population

BACKGROUND

To explore the association of cigarette smoking with retinal thickness and vascular structure in an elderly Chinese population.

METHODS

This cross-sectional study enrolled employees and retirees aged over 50 years at Tianjin University of Sport from October 2020 to December 2020. Information on smoking status and lifestyle was obtained using a detailed questionnaire. All participants underwent full ophthalmic examination. OCTA image was acquired. Vascular and the thickness parameters in central fovea and peripapillary parameters were automatically calculated. Multiple linear regression analyses were utilized to assess the association of smoking with retinal thickness and vascular structure after controlling potential confounders.

RESULTS

Compared with non-smoking adults, current smokers (β=-36.78; P = 0.01) and ever smokers (β=-35.45; P = 0.00) tended to have thinner macular fovea. Cigarettes daily, pack-years of smoking and CSI were negatively related to macular thickness (cigarettes daily: β=-1.43; pack-years: β=-14.73; CSI: β=-14.70), while they were positively associated with the circumference (cigarettes daily: β=0.03; pack-years: β=0.30; CSI: β=0.31) and the area of FAZ (cigarettes daily: β=0.01; pack-years: β=0.07).

CONCLUSIONS

Cigarette smoking seems associated with decreased macular fovea thickness and elevated circumference and area of the FAZ compared to non-smokers. Our data add to evidence of smoking on retinal thickness and the microvascular system in the macular area.

The hazards of smoking and the benefits of cessation: a critical summation of the epidemiological evidence in high-income countries

In high-income countries, the biggest cause of premature death, defined as death before 70 years, is smoking of manufactured cigarettes. Smoking-related disease was responsible for about 41 million deaths in the United States, United Kingdom and Canada, cumulatively, from 1960 to 2020. Every million cigarettes smoked leads to one death in the US and Canada, but slightly more than one death in the UK. The 21^st century hazards reveal that smokers who start smoking early in adult life and do not quit lose a decade of life expectancy versus non-smokers. Cessation, particularly before age 40 years, yields large reductions in mortality risk. Up to two-thirds of deaths among smokers are avoidable at non-smoking death rates, and former smokers have about only a quarter of the excess risk of death compared to current smokers. The gap between scientific and popular understanding of smoking hazards is surprisingly large.

[Tobacco: the construction of policies for control of its consumption in Brazil]

Brazil is a country that stands out worldwide in the reduction of smoking due to its effective control policies. By means of a narrative review, the article analyzes the nature of the scientific discussions that underpin these public policies from historical, social, health and economic perspectives. The fact that the measures associated with these issues have been marked by conflicts of interest between the tobacco industry and health organizations is highlighted. Themes related to advertising, harm reduction, tax policies and actions to protect nonsmokers are scrutinized. New stipulations on tobacco advertising are examined and, by comparative analysis, a veto on the advertising of alcoholic beverages in the country is suggested.

A practical guide to big data

Big Data is increasingly prevalent in science and data analysis. We provide a short tutorial for adapting to these changes and making the necessary adjustments to the academic culture to keep Biostatistics truly impactful in scientific research.

Association between chronic hepatitis C and hepatitis C/HIV co-infection and the development of colorectal adenomas

BACKGROUND

Limited knowledge exists about the effects chronic hepatitis C virus (HCV) infection has in the development of colorectal adenomas (CRA). Data regarding the association between chronic HIV infection and the development of CRA is scarce as well. We aim to determine if there is an association between the development of CRA and chronic infection with HCV and HCV/HIV co-infection.

METHODS

From July 1, 2009 to March 31, 2011 a total of 2,051 patients that underwent colonoscopy were included in our study. The population was divided into 2 study groups: those patients who tested positive for HCV, and HCV/HIC; the control groups consisted of patients whose results were negative. Fisher's exact χ(2) test for categorical variables and t-test for continuous variables was used to analyze data between groups. Logistic regression was performed to obtain odds ratios (OR).

RESULTS

CRA detection was higher in the HCV than in the control group (26.3% vs. 20.2%; P=1.02); Likewise, the incidence of CRA (25.5% vs. 20.8%; P=0.63) was higher in the co-infection group. However, in both of the study groups this difference was non-statistical.

CONCLUSIONS

A higher detection rate of CRP was seen in the HCV population; however, it failed to reach statistical significance. Whether co-infection with HIV/HCV increases the incidence of CRA and/or has a synergistic effect remains to be determined. The small sample population and the retrospective single institution nature of our study, as well as other confounders may have contributed to our negative results. However, our findings question whether HCV and HIV/HCV co-infected patients will benefit from screening colonoscopy at an earlier age. This issue merits further investigation with a large multi-center prospective study.

Epidemiology and the Tobacco Epidemic: How Research on Tobacco and Health Shaped Epidemiology

In this article, I provide a perspective on the tobacco epidemic and epidemiology, describing the impact of the tobacco-caused disease epidemic on the field of epidemiology. Although there is an enormous body of epidemiologic evidence on the associations of smoking with health, little systematic attention has been given to how decades of research have affected epidemiology and its practice. I address the many advances that resulted from epidemiologic research on smoking and health, such as demonstration of the utility of observational designs and important parameters (the odds ratio and the population attributable risk), guidelines for causal inference, and systematic review approaches. I also cover unintended and adverse consequences for the field, including the strategy of doubt creation and the recruitment of epidemiologists by the tobacco industry to serve its mission. The paradigm of evidence-based action for addressing noncommunicable diseases began with the need to address the epidemic of tobacco-caused disease, an imperative for action documented by epidemiologic research.

The Johns Hopkins Bloomberg School of Public Health: A Brief History of a Century of Epidemiologic Discovery

During its first century, the Johns Hopkins University Bloomberg School of Public Health has been home to several faculty members who have played leading roles in defining and expanding the field and science of epidemiology. They have done so by training leaders in the field, creating new methods and applications, and making relevant discoveries in the worlds of infectious and chronic diseases. These methodologic innovations and discoveries underlie many of today's major health policies and practices.

Cigarette smoking and cardiovascular events: role of inflammation and subclinical atherosclerosis from the MultiEthnic Study of Atherosclerosis

OBJECTIVES

To examine the contemporary effect of smoking in a multiethnic sample, and to explore the respective contributions of inflammation and subclinical atherosclerosis to the cardiovascular consequences of smoking.

APPROACH AND RESULTS

We studied 6814 participants free of cardiovascular disease and coronary heart disease (CHD) from the Multiethnic Study of Atherosclerosis. Smoking status and cumulative exposure were determined by self-report and confirmed by urinary cotinine. Multivariable Cox regression was used to estimate the association between smoking parameters and all-cause cardiovascular disease, all-cause CHD, and hard CHD events. We further adjusted for high-sensitivity C-reactive protein and coronary artery calcium (CAC) in hierarchical Cox models. We identified 3218 never smokers, 2607 former smokers, and 971 current smokers. Median follow-up was 10.2 years. Compared with never smokers, adjusted hazard ratios in current smokers were 1.7 (95% confidence interval, 1.3-2.2) for all-cause cardiovascular disease, 1.6 (1.1-2.1) for all-cause CHD, and 1.7 (1.2-2.4) for hard CHD. Similarly, among current smokers, hazard ratios were higher in the 4th versus 1st quartile of pack-years (eg, all-cause CHD hazard ratio=2.7 [1.1-6.6]). Both CAC>100 and high-sensitivity C-reactive protein ≥3 mg/L identified higher relative risk among current smokers (eg, all-cause CHD hazard ratio of 3.0 [1.5-6.0, compared with CAC=0] and 2.6 [1.4-4.8, compared with high-sensitivity C-reactive protein <2 mg/L], respectively). However, CAC was a stronger mediator of events and adversely modified the effect of smoking on events (eg, P-interaction=0.02 for hard CHD). Compared with never smokers, former smokers (median cessation interval=22 years) had similar adjusted hazard for events.

CONCLUSIONS

In this multiethnic cohort, current smoking and cumulative exposure remain important modifiable determinants of cardiovascular disease. Both high-sensitivity C-reactive protein ≥3 mg/L and, particularly, CAC>100 identified high-risk smokers who may benefit from more intensive smoking-cessation efforts.

A century of smoke

Tobacco kills 5 million people annually. By the mid 2020s, that figure will increase to about 10 million a year, with most of the deaths occurring in developing countries. This review explains how early technological and regulatory developments contributed to the epidemic, reveals the efforts of the tobacco industry to conceal its products' harmfulness, and stresses the role of the globalization of trade and marketing as a means of increasing consumption world-wide. The results of tens of thousands of studies published globally over the past 50 years point to an association between smoking and lung cancer and other adverse health effects, and the non-smoker's rights movement has exposed the wide-spread perils of 'secondhand' smoke. Yet, the tobacco industry continues its global expansion, and consumers in low- and middle-income countries are especially susceptible to its marketing tactics. This review ends by emphasising the need for a global public-health response, and identifies the Framework Convention on Tobacco Control as a significant effort. It stresses the need for accelerated action and innovative tobacco-control efforts, if the projected death toll is to be reduced in this century.

Tobacco smoking: the leading cause of preventable disease worldwide

Tobacco smoking is the world's leading cause of avoidable premature mortality, reflecting the potent toxicity of tobacco smoke inhaled by smokers for decades. In the twentieth century, lung cancer was an early sentinel of the emergence of the still persisting epidemic of tobacco-caused disease. Smoking has declined in many countries, particularly the high-income countries, but low- and middle-income countries remain at risk because of the aggressive tactics of tobacco multinationals. The World Health Organization treaty, the Framework Convention on Tobacco Control, is a critical factor in countering these tactics and precipitating the end of the global epidemic of tobacco smoking.

Do socio-economic gradients in smoking emerge differently across time by gender? Implications for the tobacco epidemic from a pregnancy cohort in California, USA

Understanding current patterns of population smoking by socioeconomic position (SEP) can be substantially enhanced by research that follows birth cohorts over long periods of time, yet such data in the US are rare. Information from birth cohorts followed during critical time periods when the health consequences of smoking became widely known can inform the ways in which current smoking prevalence has been shaped by the historical processes that preceded it. The present study utilizes data from a substudy of the Child Health and Development Study pregnancy cohort (N = 1612). Women were queried about smoking status in 1959-1962, 1971-1972 and 1977-1980. Women were divided into three cohorts based on date of birth. Offspring represented another birth cohort assessed for smoking in 1977-1980. Results indicated that the overall prevalence of smoking exhibited cohort-specific patterns that persisted across time. Notably, the youngest maternal cohort (born 1937-1946) had high smoking prevalence throughout and showed no appreciable decrease (44.7%, 41.4%, 40.1% for 1959-1962, 1971-1972, and 1977-1980). Results also indicated that the relation of smoking to SEP exhibited cohort-specific patterns over time. Among the oldest birth cohort (born 1914-1930), no inverse relation of SEP to smoking was observed at any time; in contrast, an inverse relation emerged by 1959-1962 among the youngest cohort of mothers. Among the adolescent offspring, there was a strong SEP gradient (OR = 2.0, 95% CI = 1.4-3.0) that was stronger than in any maternal birth cohort at any assessment (β = 0.40, SE = 0.1, p<0.01). We conclude that SEP gradients in smoking emerge across birth cohorts rather than time alone, with increasingly strong gradients across time especially among younger cohorts.

[Risk factor "smoking" : smoking cessation in patients with cardiovascular diseases]

Smoking is the most frequent cause of avoidable premature death. Annually, almost 6 million people die due to nicotine consumption. Comparing modifiable cardiovascular risk factors, smoking has the strongest impact on cardiovascular mortality. More than 50% of all premature myocardial infarctions are related to nicotine consumption. Even in patients with known coronary disease receiving optimal medical therapy, there is a remarkable additional preventive effect of smoking cessation detectable. Therefore, smoking cessation is an essential component of primary and secondary prevention strategies. Smoking cessation programs applying a combination of behavior therapy and supporting medical treatment have been demonstrated to be the most effective.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

A Review of Lifetime Risk Factors for Mortality

This review was undertaken for the Faculty and Institute of Actuaries as part of their programme to encourage research collaborations between health researchers and actuaries in order to understand better the factors influencing mortality and longevity. The authors presented their findings in a number of linked sessions at the Edinburgh conference (Joining Forces on Mortality and Longevity) in October 2009 and contributed to this overview. The purpose is to review evidence for the impact on adult mortality of characteristics of the individual's lifetime socioeconomic or psychosocial environment or phenotype at the behavioural; multi-system (e.g. cognitive and physical function); or body system level (e.g. vascular and metabolic traits) that may be common risk factors for a number of major causes of death. This review shows there is growing evidence from large studies and systematic reviews that these individual characteristics, measured in pre-adult as well as the adult life, are associated with later mortality risk. The relative contribution of lifetime environment, genetic factors and chance, whether these contributions change with age, and the underlying social and biological pathways are still to be clarified. This review identifies areas where further life course research is warranted.

The Johns Hopkins Center for Global Health: transcending borders for world health

The causes and effects of many health problems, whether infectious, environmental, lifestyle related, or caused by manmade or natural disasters, are becoming increasingly global in nature. Integrated approaches to solving these problems require the expertise of large and diverse groups of health professionals, to design lifesaving research and to implement effective responses. The Johns Hopkins University public health, medical, and nursing communities have a history of leadership in both modern medicine and public health, and they have unparalleled human resources in the clinical, research, programmatic, policy, and educational domains, with an extensive network of international colleagues and collaborators. To best utilize these resources to have a positive impact on global health issues, the university created the Center for Global Health in 2006 to facilitate and coordinate the various international activities of the faculty and students in the field of global health. The center has seven specific initiatives aimed at educating students and facilitating the faculty's collaborative research: serving as a resource center for global health activities within the university; facilitating and coordinating topical areas of global research; promoting educational programs in global health; providing global health field training grants; granting global health scholarships; focusing on global health research and practice; and coordinating symposia, forums, and policy initiatives. The author elaborates on these initiatives and discusses challenges experienced in establishing the center, as well as evaluation methods for determining the center's success.

[Significance of changes in habits followed by risk reduction]

Cardiovascular risk is substantially influenced by changes in habits. In this context the INTERHEART study showed that a healthy vitamin-packed nutrition and regular workout reduced the cardiovascular risk up to 79%. In this case people older than 50 years would benefit most from change. Patients suffering from obesity should combine a low-calory diet with physical training in order to reduce weight. Here optimal results can be achieved by considering intensity as well as quantity for each patient.

A cross-cultural and historical survey of tobacco use among various ethnic groups

This review of tobacco use in diverse historical and cultural contexts reveals a range of behaviors engaged in and perspectives held by members of respective ethnic groups, such as whether to consider tobacco as a medicine or as a problem. After its introduction to Western societies, many attributed tobacco with an array of medicinal uses, while condemning recreational use and identifying it as immoral. Tobacco has been used variously by respective ethnic groups at different times and places and these customs have flavored understandings of the relationships between tobacco and the body. Considerable ethnic variation exists not only in terms of tobacco use and abuse, but also with respect to pharmacogenetic factors that influences the consequences of tobacco exposure. There have also been different societal responses to the use of tobacco, including those related to the media, as well as to issues of treatment and prevention.

Globalization and Tobacco

This chapter reviews the evolving economic and social system sustaining the growing tobacco epidemic in order to identify how globalization is affecting the industry, governments, and tobacco control advocates. It is divided into four main sections. The first section recalls key historical events that led to the worldwide prominence of tobacco use and the global rise of tobacco-related death and disease. The second section examines scientific evidence regarding the health effects of active and passive smoking and reviews the globalization of the public health response to the tobacco epidemic. The third section describes the Framework Convention on Tobacco Control (FCTC) negotiating process and final treaty text. The fourth section analyzes some of the remaining major challenges resulting from working within a global system, in particular, those challenges associated with developing coherent domestic and international policies and the permanent need to anticipate the unintended consequences of national and global regulations. The chapter concludes by identifying new directions and resources for global tobacco control and predicting some of the main challenges that lie ahead.

The pathophysiology of cigarette smoking and cardiovascular disease: an update

Cigarette smoking (CS) continues to be a major health hazard, and it contributes significantly to cardiovascular morbidity and mortality. Cigarette smoking impacts all phases of atherosclerosis from endothelial dysfunction to acute clinical events, the latter being largely thrombotic. Both active and passive (environmental) cigarette smoke exposure predispose to cardiovascular events. Whether there is a distinct direct dose-dependent correlation between cigarette smoke exposure and risk is debatable, as some recent experimental clinical studies have shown a non-linear relation to cigarette smoke exposure. The exact toxic components of cigarette smoke and the mechanisms involved in CS-related cardiovascular dysfunction are largely unknown, but CS increases inflammation, thrombosis, and oxidation of low-density lipoprotein cholesterol. Recent experimental and clinical data support the hypothesis that cigarette smoke exposure increases oxidative stress as a potential mechanism for initiating cardiovascular dysfunction.

Cigarettes and the US Public Health Service in the 1950s

The conclusion of the United States Surgeon General's Advisory Committee on Smoking and Health in 1964 that excessive cigarette smoking causes lung cancer is cited as the major turning point for public health action against cigarettes. But the surgeon general and US Public Health Service (PHS) scientists had concluded as early as 1957 that smoking was a cause of lung cancer, indeed, "the principal etiologic factor in the increased incidence of lung cancer." Throughout the 1950s, however, the PHS rejected further tobacco-related public health actions, such as placing warning labels on cigarettes or creating educational programs for schools. Instead, the agency continued to gather information and provided occasional assessments of the evidence as it came available. It was not until pressure mounted from outside the PHS in the early 1960s that more substantive action was taken. Earlier action was not taken because of the way in which PHS scientists (particularly those within the National Institutes of Health) and administrators viewed their roles in relation to science and public health.

Preventive health care for older women: life-style recommendations and new directions

One of the key paradoxes in gerontology is that, despite a higher longevity, aging women experience worse health and longer disability than men. However, there is growing evidence that changes in life-style, medical interventions and systematic screening for certain diseases may substantially reduce the excess risk of major chronic conditions and disability in aging women, and therefore improve the quality of their late life. The potentials and public health implications of prevention in older women have been recently emphasized, not only by the scientific literature, but also by the media. More and more women are turning to their primary care physicians or other health professionals to seek counselling and help on how to reduce the burden of chronic disease and disability in old age by quitting smoking, eating a healthy diet, increasing physical activity, and coping with stress. Hormone replacement therapy also has a central role in this action of prevention. To maximize compliance, women should be provided a few guidelines that are easy to understand, and can be followed without interfering too much with their daily life activities. This article reviews the current literature on prevention in older women to select preventive strategies that are based on robust scientific evidence. This list of guidelines should be considered as a starting point for all those who are in charge of caring for middle-aged and older women.

Effects of cigarette smoking on gastric ulcer formation and healing: possible mechanisms of action

Epidemiologic studies have shown that cigarette smoking is closely related to peptic ulcer disease. The mechanisms by which cigarette smoking adversely affects gastric mucosa have been suggested and elucidated. This article reviews some of the mechanisms involved in cigarette smoking-related gastric ulceration and healing. Experimental findings suggest that cigarette smoking increases xanthine oxidase activity, leukotrienes, and nitric oxide production and also neutrophil infiltration in the gastric mucosa. On the other hand, it reduces blood flow, prostaglandin production, epithelial cell proliferation, and formation of blood vessels in the tissue. These actions are important for ulcer formation and healing. The evidence thus far available strengthens the hypothesis that cigarette smoke is indeed harmful to gastric mucosa through defined mechanisms.

Uncovering the effects of smoking: historical perspective

Tobacco was introduced into Europe from America at the end of the fifteen century. At first used primarily for medicinal purposes it came to be burnt in pipes for pleasure on a large scale nearly 100 years later, at first in England and subsequently in Europe and throughout the world. Pipe smoking gave way to the use of tobacco as snuff and, in turn, to cigars and cigarettes at different times in different countries until cigarette smoking became the dominant form in most of the developed world between the two world wars. Societies were formed to discourage smoking at the beginning of the century in several countries, but they had little success except in Germany where they were officially supported by the government after the Nazis seized power. In retrospect it can now be seen that medical evidence of the harm done by smoking has been accumulating for 200 years, at first in relation to cancers of the lip and mouth, and then in relation to vascular disease and cancer of the lung. The evidence was generally ignored until five case-control studies relating smoking to the development of lung cancer were published in 1950. These stimulated much research, including the conduct of cohort studies, which, by the late 1950s, were beginning to show that smoking was associated with the development of many other diseases as well. The interpretation that smoking caused these various diseases was vigorously debated for some years but came to be generally accepted in respect of lung cancer by the late 1950s and of many other diseases in the subsequent two decades. Cigarette smoking has now been found to be positively associated with nearly 40 diseases or causes of death and to be negatively associated with eight or nine more. In some instances the positive associations are largely or wholly due to confounding, but the great majority have been shown to be causal in character. The few diseases negatively associated with smoking are for the most part rare or nonfatal and their impact on disease incidence and mortality as a result of smoking is less than 1% of the excess of other diseases that are caused by smoking. The most recent observations show that continued cigarette smoking throughout adult life doubles age-specific mortality rates, nearly trebling them in late middle age. All the diseases related to smoking that cause large numbers of deaths should now have been discovered, but further nonfatal diseases may remain to be revealed by cohort studies that are able to link individuals' morbidity data with their personal characteristics.

Effects of smoking on survival and morbidity in patients randomized to medical or surgical therapy in the Coronary Artery Surgery Study (CASS): 10-year follow-up. CASS Investigators

OBJECTIVES

The goal of this study was to ascertain how continued cigarette smoking or smoking cessation related to long-term survival and morbidity in patients with established coronary artery disease managed with medical therapy or coronary bypass surgery.

BACKGROUND

Although the association of cigarette smoking with coronary artery disease is well established, the morbidity and mortality associated with smoking behavior in patients with such disease receiving medical or surgical therapy are less well established.

METHODS

The 780 patients randomized to medical therapy or coronary bypass surgery in the Coronary Artery Surgery Study (CASS) were subgrouped according to smoking behavior during a mean 11.2-year follow-up interval. Comparisons between smokers and nonsmokers were accomplished by univariate and Cox time-dependent multivariate analyses.

RESULTS

Survival at 10 years after entry into the study was 82% among 468 patients who reported no smoking during follow-up (nonsmokers) compared with 77% among the 312 smokers (p = 0.025). Survival was 80% among those who smoked at entry but stopped (quitters) versus 69% among those who continued smoking (p = 0.025). For patients who smoked at baseline and were randomized to bypass surgery, survival at 10 years was 84% among quitters and 68% among nonquitters (p = 0.018); the difference in survival between quitters (75%) and nonquitters (71%) was less among those randomized to medical therapy (p = NS). Among those who smoked at baseline, continued smoking increased the relative risk of death by 1.73. After 10 years, smokers, in comparison with nonsmokers, were less likely to be angina free and more likely to be unemployed and had more activity limitation and more hospital admissions (primarily for chest pain, heart attack, cardiac catheterization, peripheral vascular surgery and stroke).

CONCLUSIONS

Thus, among patients with documented coronary artery disease, continued cigarette smoking may result in decreased survival--especially among those undergoing bypass surgery. Moreover, smokers have more angina, more unemployment, a greater limitation of physical activity and more hospital admissions.

The health benefits of smoking cessation

Extensive evidence has now accumulated on the health benefits of smoking cessation. With few exceptions, disease risks are reduced following smoking cessation and continue to drop as abstinence is maintained. The review of the evidence in the 1990 Report of the Surgeon General led to major conclusions that establish smoking cessation as a clear priority for health care providers.

The peripheral vascular consequences of smoking

Cigarette smoking is associated with an increased risk and extent of advanced atherosclerotic vascular disease in peripheral as well as coronary arteries. The likelihood of claudication, amputation, stroke, abdominal aortic aneurysm, and failure of vascular reconstruction is higher in smokers than nonsmokers. Smoking exerts its deleterious effects through many interactive mechanisms. Nicotine and carbon monoxide produce acute cardiovascular consequences, including altered myocardial performance, tachycardia, hypertension, and vasoconstriction. Smoking injures blood vessel walls by damaging endothelial cells, thus increasing permeability to lipids and other blood components. Among metabolic and biochemical changes induced by smoking are elevated plasma, free fatty acids, elevated vasopressin, and a thrombogenic balance of prostacyclin and thromboxane A2. Chronic smoking is associated with a tendency for increased serum cholesterol, reduced high density lipoprotein, and other lipid effects that contribute to atherosclerosis. In addition to rheologic and hematologic changes from increased erythrocytes, leukocytes, and fibrinogen, smokers have alterations in platelet aggregation and survival that produce thrombosis. Considering the ubiquitous repercussions of this menace, vascular surgeons should play an active role in motivating their patients to quit smoking.

Interactive effects of age and other risk factors on long-term survival after coronary artery surgery

The effect of age at the time of coronary artery bypass graft surgery on postoperative survival was studied in 2,507 patients with significant coronary artery disease. Patients were subdivided into five groups based on age at the time of surgery: 20 to 39, 40 to 49, 50 to 59, 60 to 69 and greater than or equal to 70 years. The observed death rate was compared with that expected for subjects from the general U.S. population matched for age, gender, race and calendar year. For patients less than or equal to 59 years of age, the ratio of observed to expected death rates was significantly greater than unity (observed/expected = 4.9 for ages 20 to 39, 1.9 for ages 40 to 49 and 1.3 for ages 50 to 59 years, p less than 0.01). The prevalence of risk factors, including diabetes mellitus, hypertension, hypercholesterolemia and cigarette smoking, was evaluated in the different age subgroups. When patients were subdivided on the basis of history of cigarette smoking, the decreased relative survival rate of younger (less than 60 years old) patients existed only in those who smoked (observed/expected = 6.0 for ages 20 to 39, 2.2 for ages 40 to 49 and 1.4 for ages 50 to 59 years). In nonsmokers, observed/expected ratios for every age group were not significantly different from unity. Thus, the reduced relative survival rate of younger patients after coronary artery bypass graft surgery may be attributed to the interactive harmful effects of cigarette smoking.

Background of the prevention of cardiovascular disease. II. Arteriosclerosis, hypertension, and selected risk factors

The prevention of cardiovascular disease antedates our current preoccupation with risk factors for coronary heart disease and hypertension. Indeed, earlier preventive efforts have in part been so successful that many people have forgotten that they existed. The almost forgotten entity, beriberi heart disease, was first prevented in 1883 by Takaki of Japan. With diphtheria, it was the identification of the causative bacillus by Klebs in 1883, leading finally to the development of diphtheria toxoid by Ramon in 1923, which resulted in the disappearance of diphtheritic heart disease. Success in the attack on syphilitic heart and vascular disease began with Bordet and Gengou in 1901 with the discovery of the phenomenon of complement fixation, and with the formulation of Salvarsan by Ehrlich in 1907. The story of the prevention of rheumatic fever has a large cast of characters, but special recognition must be given to Coburn for his observations confirming the role of the hemolytic streptococcus published in 1931 and showing the prophylactic value of sulfanilamide published in 1939. The important association of maternal rubella with congenital heart malformations was revealed by Gregg in 1941. Alcoholic heart disease was identified particularly by Brigden and Evans in 1957 and 1959, respectively. In relation to coronary and hypertensive heart disease, the names of Anitschkow (1933), Leary (1935), and Keys (1948) in relation to diet, of Freis (1967) in the field of hypertension treatment, of White (1927) in relation to physical exercise, and of English, Willius, and Berkson (1940) and Hammond and Horn (1954) in the role of cigarette smoking, deserve special recognition.

Multistage models for carcinogenesis

The multistage model is tested on several human and animal data sets. It fits in some cases but not in others. With human lung cancer data, there is a drop in risk for ex-smokers quite different from the predictions of the model. The results are not conclusive but are compatible with the view that the multistage model provides a family of curves that often fit cancer incidence data, but may not capture the underlying biological reality.