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 as to 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, 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 up to the present, Kabat shows how publication of more rigorous studies and critical assessments ultimately helped put the hazard in perspective.
an honest epidemiologist In a dispassionate and painstaking way, Kabat sheds light on four health scares: radon, electromagnetic fields from power lines, DDT as a cause of breast cancer, and second-hand tobacco smoke. If epidemiologists are to contribute useful insights, they need to be mindful of weaknesses in evidence. Kabat quotes a distinguished pioneer of identifying risks associated with cigarettes, Sir Richard Peto: "epidemiology is so beautiful and provides such an important perspective on human life and death, but an incredible amount of rubbish is published." After hyping by journalists, rubbish can be given undue credibility by governments eager to respond to public concerns or by self-interested politicians and advocates. John Ioannadis: "In the past, we had few research findings, while currently we have too many research findings. Therefore, getting rid of tentative but wrong research findings should become at least as important as finding new ones." Kabat supports weighing evidence in a critically-minded, inter-disciplinary way. The only way to overcome misinformation is via stronger science. Chapter 2 overviews the field of epidemiology. Kabat mentions examples of valuable achievements: cholera as a water-borne disease; smoking and cancers; alcohol and cancers; risk factors for heart disease; estrogen, progesterone and breast cancer; sleep position and sudden infant death syndrome; solar radiation and skin cancer; hepatitis b and liver cancer. Cholera was a clear cause, a problem amenable to investigation by mapping victims and water supplies. Nowadays, in contrast, some investigate modest health effects by looking at unlikely risk factors (a few chemical exposures within the myriad that we humans routinely encounter, needles in haystacks). Kabat readably integrates narrow articles into an understandable big picture. Yale physicist William R. Bennett (pioneer of gas lasers that serve us via grocery store scanners and compact disks) calculated a barefoot railroad worker standing on wet tracks bearing electric current would receive a dose orders of magnitude lower than fields normally inside our bodies. New England Journal of Medicine: "all these epidemiological studies have been conducted in pursuit of a cause of cancer for which there is no plausible biologic basis." Kabat: "it is hard to escape the impression that the reluctance of the National Institute for Environmental Health Sciences working group to close the door on the possibility of electromagnetic force as a cause of leukemia had more to do with its members' stake in this area of research than with scientific rigor." Tunnel vision kept epidemiologists focused on their studies "to the exclusion of fundamental insights about the phenomenon whose effects they were investigating." Epidemiology should assist other disciplines, not myopically disregard them. It is when health scares are at their most contentious that society is in most need of scientists willing to look rigorously and honestly at a topic, without succumbing to prevailing winds of fashion. Without an unswerving commitment to integrity, science is reduced to science fiction and ill-serves the public good. Kabat offers worthy lessons to epidemiologists who aspire to serve via honest practice. Well done.
Truthful epidemiology is not always politically correct Kabat's book should be required reading for all public health graduate students and single-issue health activists. From the office of the Surgeon General to city hall, advocacy has frequently supplanted sound science in the service of "good public health policy". The hallmark of advocacy triumphing over science is a selective and result oriented use of data, starting with the institutions that fund the studies. It is currently heresy to challenge the science behind ETS research and regulation. You cannot get a study approved that challenges the validity of the questionnaires and other proxy measures used to characterize ETS exposure, or openly seeks to challenge inadequate measures of bias and confounding. As a consequence, a mountain of research money is being spent piling on more biased studies conducted by advocates. It's not a conspiracy. It is what political correctness does to public health. We need more public health heretics like Kabat.
Artificial Hyping of Risks Professor Kabat does an excellent job in describing how a combination of zealous regulators, activists, and media can combine to magnify "alarming" results of preliminary, usually inadequate or poorly done studies. Once these headlines are in the public psyche, it can take years, even decades, of further, expensive studies to demonstrate the early alarms were false. Meanwhile, many are scared, and billions of dollars are spent to "fix" or "avoid" the so-called problem.
Four examples are explored in detail, complete with literature references. They are: a) environmental chemicals can cause breast cancer, b) electromagnetic fields (mostly from power lines) can cause various cancers, c)radon gas in homes can cause lung cancer, and d)the (lack of)effects of second-hand smoke. The discussions are thorough and convincing. In addition, Professor Kabat has a chapter describing the science of epidemiology, and points out the usefulness as well as the weakness of the technique.
This is an excellent read for both the layman and the professional in the field.
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