Hyping Health Risks

Environmental Hazards in Daily Life and the Science of Epidemiology

Geoffrey C. Kabat

• Publisher: Columbia University Press
• Year: 2008
• eBook ISBN: 9780231511964
• Topic: Medicine
• Subtopic: Epidemiology

The media constantly bombard us with news of health hazards lurking in our everyday lives, but many of these hazards turn out to have been greatly overblown. According to author and epidemiologist Geoffrey C. Kabat, this hyping of low-level environmental hazards leads to needless anxiety and confusion on the part of the public concerning which exposures have important effects on health and which are likely to have minimal or no effect.

Kabat approaches health scares as "social facts" and shows that a variety of factors can contribute to the inflating of a hazard. These include skewed reporting by the media, but also, surprisingly, the actions of researchers who may emphasize certain findings while ignoring others; regulatory and health agencies eager to show their responsiveness to the health concerns of the public; and politicians and advocates with a stake in a particular outcome.

By means of four case studies, Kabat demonstrates how a powerful confluence of interests can lead to overstating or distorting the scientific evidence. He considers the health risks of pollutants such as DDT as a cause of breast cancer, electromagnetic fields from power lines, radon within residences, and secondhand tobacco smoke. Tracing the trajectory of each of these hazards from its initial emergence to the present, Kabat shows how publication of more rigorous studies and critical assessments ultimately help put hazards in perspective.

1

INTRODUCTION
Toward a Sociology of Health Hazards in Daily Life

Each society shuts out perception of some dangers and highlights others.

We moderns can do a lot of politicizing merely by our selection of dangers.

—Mary Douglas and Aaron Wildavsky, 1982

We are all familiar with what has been referred to as the “hazard du jour” phenomenon. Typically, it starts with media reports of the findings of a new scientific study indicating that some lifestyle behavior, consumer product, or environmental factor is linked to some dire disease. Coffee drinking is linked to pancreatic cancer. Eating chocolate is claimed to dispose to benign breast disease in women. Environmental pollution, we are told, may cause breast cancer. Studies appear to show a connection between exposure to electromagnetic fields from power lines and electric appliances and a host of diseases, starting with childhood leukemia. Use of cellular telephones may lead to brain tumors. Exposure to secondhand tobacco smoke, or passive smoking, is linked first to lung cancer, then to heart disease, and most recently to breast cancer. Silicone breast implants are associated with connective tissue disorders. The list could be extended at great length. Following the initial report, a second report may appear soon after yielding further suggestive evidence of a hazard or, just as often, showing no effect. In this way, over time, a scientific literature develops on each topic marked by weak and inconsistent results, and the perception of a hazard takes on a reality.

Some scares, such as those surrounding coffee and cell phones, may subside fairly quickly, as better studies are published or as the hazard is put in perspective and deflated. In other cases, the hazard can take on a life of its own and persist over years or decades, becoming the focus of scientific research, regulatory action, lawsuits, and advocacy campaigns. In the case of electromagnetic fields from power lines, tens of billions of dollars have been spent to remediate a problem whose very existence is uncertain. But what characterizes all of these scares is that the public’s perception of a hazard was greatly exaggerated and was not counterbalanced by an awareness of the tenuousness of the scientific evidence or of the relatively modest magnitude of the potential risk. Thus, to a large extent, when one examines the public’s response to a high-profile health scare, one is dealing with the dissemination of poor information and appeals to fear. (It sometimes seems that the intensity of the fear is inversely proportional to the actual magnitude of the threat.)

To be sure, reporting of hazards in the media tends to reduce any question to the simplistic message that exposure X may cause condition Y, and the extensive background and necessary qualifications are rarely provided. But media attention to health hazards is only a symptom of a pervasive preoccupation in our society with risks to our health, and to understand their significance, one has to examine both the context and the full range of contributing factors. The distortion and inflation of health hazards is the result of a complex interplay between the consumers of information about health risks (the media, the public, activist groups) and the producers of this information (scientists and regulators), and the influences between these groups flow in both directions.

The processes and mechanisms by which the available scientific evidence on a question can be distorted have received little attention. This is not surprising. For one thing, studies in the areas of epidemiology and environmental toxicology are highly technical, and often there is disagreement among scientists about the available evidence and about the importance of a given agent, making it difficult for nonspecialists to evaluate. Furthermore, practicing scientists may not be inclined to look back and assess their own work critically or to examine the factors that led them to devote attention to a particular question as opposed to another. If one line of work does not pan out, scientists move on to something new, which is, by definition, “exciting” and “promising.” Science, like other disciplines, has its own internal structure of incentives and rewards that keep practitioners focused on the goals of improving methods and conducting more rigorous and powerful studies of questions that are agreed at a given point in time to be important. There is little incentive, therefore, to question the value of research on a specific topic, especially when that topic is of great concern to the public and regulators. But there are other reasons for the failure to examine certain health risks objectively, which we will come to in a moment.

In addition to practitioners directly involved in public health, psychologists and others have devoted attention to the new academic disciplines of “risk perception” and “risk communication.” Their objective has been to describe how people interpret information about various risks and how this calculus influences personal behavior and public policy. While contributing valuable insights, work in this area generally ignores how science is actually carried out, the impact of external factors on science, and the context in which its findings are interpreted and communicated to the public—precisely the issues that are central to this book. It is striking that some of the key collections of papers on risk perception make virtually no mention of epidemiology.¹ This can be explained by the fact that these new disciplines focus on the consumers of information regarding risk rather than on its producers.

The purpose of this book is to elucidate how confusion about what is a threat comes about and what factors—both internal and external to science—contribute to it. How do certain perceived health hazards get blown out of proportion, in spite of well-known facts that should help to keep irrational fear within bounds? In attempting to address these questions, I have set myself three distinct but interconnected aims. First, I try to sketch out the variety of factors and processes that contribute to the manufacture of a hazard. Second, by introducing the reader to the basics of the science of epidemiology, I demonstrate the difference between well-established, important hazards and small, uncertain, or hypothetical hazards. Finally, in four detailed case studies I attempt to show how particular hazards have been inflated.

Health hazards of the kind that get seized on by the media, studied by different scientific disciplines, addressed by regulatory agencies, contested in the courts, and embraced by advocacy groups are what the nineteenth century father of sociology Émile Durkheim termed “social facts.” That is, they are reflections of a particular society, and they function in specific ways within that society. To understand how certain health risks become greatly exaggerated, what is needed is an approach that incorporates an examination of the context in which science is carried out in the area of public health and how pressures and agendas that are internal as well as external to science can influence both what is studied and what is made of the scientific evidence. In other words, what is needed is a sociology of science in this area. This chapter attempts to describe the landscape in which certain health risks have been selected and distorted. Specifically, I examine the different groups and institutions that have played a role in the manufacture of several prominent hazards, as well as key considerations that have frequently been lost sight of in the public, and, even in the scientific, discussion.

THE RISE OF EPIDEMIOLOGY AND ENVIRONMENTALISM

It is a paradox of contemporary life that, although longevity as well as general health and well-being have increased dramatically in the United States over the past hundred years, we live in a society that is hyperattuned to any threat to our health, no matter how hypothetical or how small. This heightened concern about potential threats to our health stems from at least two major developments dating from the 1960s and 1970s: the rise of the field of epidemiology, the science of the determinants of disease in human populations, and the more or less concurrent rise of the environmentalist movement. Together, these two developments have not only created a new awareness of the determinants of health, but they also continuously reinforce and feed this consciousness with novel findings that command attention. Beginning with the first studies linking cigarette smoking to lung cancer and other diseases in the 1950s, findings from epidemiology have made commonplace the notion that specific behaviors and exposures may affect health. Owing to these discoveries, a new and powerful paradigm has emerged, offering the prospect that many common chronic diseases could be drastically reduced by curtailing the causative exposures. Over the same time period, the recognition of the need to regulate environmental pollution—embodied in the creation of the federal Environmental Protection Agency (EPA)—and the publicity surrounding many environmental issues—from air and water pollution to climate change—have fostered an unprecedented and widespread perception that our actions have effects on the environment and that the environment has effects on human health. While reports of specific findings may be difficult for the lay public to assess, each new report of an environmental hazard or of a putative link between an exposure and disease underscores the message that we are surrounded by myriad agents in the environment that may pose a threat to our health.²

Today the science of epidemiology occupies such a prominent place in the health sciences, in regulatory affairs, and in the news that it is easy to forget how recent a development this is. When the landmark studies linking cigarette smoking with lung cancer appeared in the early 1950s, there were no departments of epidemiology, and the methods used in these early studies were untested and were challenged by some of the most respected statisticians. During the 1960s and 1970s, epidemiology proved itself as a science by a series of important successes in identifying preventable causes of disease.³ Over the past four decades the field has grown at a prodigious rate, whether measured by the number of departments and programs in schools of public health, the number of textbooks devoted to subfields of epidemiology, or the number of research papers appearing in journals.

Since epidemiology is a young science and because, of necessity, it relies for the most part on observational, as opposed to experimental, studies, it is not surprising that many of the associations that are found and reported turn out to be spurious, that is, noncausal, associations. For one thing, chronic diseases like cancer, heart disease, and Alzheimer’s are complex, multistage, “multifactorial” conditions. (Lung cancer, which has one predominant cause—smoking—that accounts for the vast majority of cases, is probably an exception. For example, a large, international study has recently shown that ten different factors make a contribution to the occurrence of heart disease.) Furthermore, the relevant period of exposure for “diseases of long latency” like cancer and heart disease can be decades preceding the appearance of symptoms, making it difficult to establish a causal relationship. Usually, one has only crude information collected at one point in time to represent the actual exposure over this long period. Thus, a major problem confronting epidemiologic studies of low-level environmental exposures that have been the focus of public concern is that it is extremely difficult to know what an individual’s exposure was over a period of decades that may be relevant to his or her risk of developing disease.

Finally, many of the strong relationships—the low-hanging fruit, so to speak—like smoking and lung cancer and alcohol consumption and oral cancer have already been identified. It is much more difficult to reliably identify new factors that play a role in a given disease when these may be subtle, leading at most to a doubling or tripling of the risk in those with the factor compared to those without the factor. Often, we are dealing with even smaller increases of 10–100 percent. (For comparison, people who have ever smoked have a tenfold, or 1000 percent, increased risk of lung cancer; current smokers have a 20-fold risk; and heavy current smokers can have as much as a 50- or 60-fold increased risk.) Scientists who have devoted their careers to studying the possible impact of low-level environmental exposures on chronic diseases readily acknowledge the immense difficulty of establishing credible linkages.⁴ Thus, it has to be realized that many more potential “risk factors” are studied than turn out in the end to be causes of disease. This is inherent in the process of science and especially a young and nonexperimental science such as epidemiology. This basic truth is well known to any scientist, and yet when it is formulated explicitly and vigorously, it comes as a surprise.⁵ It seems, therefore, to conflict with deep, unconscious beliefs.

For these reasons, whether a hazard exists and, if so, its magnitude is often difficult to resolve. In some instances the vague penumbra of a hazard associated with a given exposure can persist for decades—despite, or because of, inconclusive evidence—contributing to a pervasive sense of distrust regarding the environment. Over time, the succession of media reports raising the possibility of new potential hazards has the contradictory effects of reinforcing a general message—the importance of “lifestyle” behaviors and the environment on health—and at the same time thoroughly confusing the public about what to believe.⁶ It is easy to see how, in many people, this torrent of “significant” findings would produce only a deep and generalized sense of anxiety or else apathy and fatalism. And such fatalism may itself be a health risk!⁷

I should note that the vast majority of research on factors influencing health never attracts the attention of the public and usually is of interest only to a small number of specialists working in a particular area. It is only when research pertains to a potential hazard that has become a focus of intense public concern and government action that the kinds of distortion and misrepresentations that I will discuss take place.⁸

THE SCIENCE CONCERNING ENVIRONMENTAL HAZARDS IS CONTESTED

Although we tend to think of science as occupying an Olympian realm that is insulated from social, political, and ideological influences, the fact is that science is not conducted in a vacuum. Historians and sociologists of science like Thomas Kuhn, Paul Feyerabend, Robert K. Merton, and Michel Foucault have drawn attention to the role of historical, social, ideological, and personal factors in the formation and acceptance of scientific ideas.⁹ Particularly in the area of science dealing with health and the environment, different groups and institutions have very different interests at stake when it comes to the science and policy concerning health risks. The starting point for any discussion of external influences on science in this area has to be industry’s long-standing and well-documented record of efforts to suppress or neutralize credible scientific evidence of adverse health effects due to its products or processes. Tobacco, asbestos, and lead are only some of the more dramatic and better known entries in this record.¹⁰ Powerful industries have routinely used their substantial resources in the legal, regulatory, and public relations spheres to put a favorable spin on the science relating to their products and to thwart regulation.¹¹ Furthermore, how vigorously regulatory agencies, like the Environmental Protection Agency and the Food and Drug Administration, confront powerful corporate interests varies with the political climate. We have recently witnessed a powerful demonstration of how the party in power can attempt to edit and mould scientific findings to fit its philosophy and the requirements of its political supporters.¹²

Given the inherent difficulty of establishing credible links between low-level exposure to environmental toxins and chronic disease, it is hardly surprising that the assessment of potential environmental health hazards is hotly contested and that there is a sharp antagonism between the proponents of unfettered freedom for commercial enterprise and those concerned with protecting the public’s health and improving occupational safety. Each side tends to cite the evidence that supports its point of view in order to influence public policy.

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Table of contents

• Cover 
• Praise for Hyping Health Risks
• Title
• Copyright
• Dedication
• Epigraph
• Contents 
• Preface
• Abbreviations
• 1: Introduction: Toward a Sociology of Health Hazards in Daily Life
• 2: Epidemiology: Its Uses, Strengths, and Limitations
• 3: Does the Environment Cause Breast Cancer?
• 4: Electromagnetic Fields: The Rise and Fall of a “Pervasive Threat”
• 5: The Science and Politics of Residential Radon
• 6: The Controversy Over Passive Smoking: A Casualty of the “Tobacco Wars”
• 7: Conclusion
• Appendix A: List of Interviews
• Appendix B: How Findings Can Be Reported in a Way That Puts Them in Perspective
• Appendix C: An Interview with the Author
• Notes
• Glossary
• Bibliography
• Credits
• Index