Are you an advocate, tacit supporter, critical skeptic or silent skeptic?

Hormonal Chaos. The Scientific and Social Origins of the Environmental Endocrine Hypothesisby Sheldon Krimsky, John Hopkins University Press, 2000, $39.95(xiii + 284 pages) ISBN 0 8018 6297 5‘Silent Sperm.’ ‘You're not half the man your grandfather was.’ ‘Assault on the Male.’ ‘Gender Benders.’ Perhaps no other public health concern has given rise to a greater number of memorable sound bites than the issue of whether environmental contaminants are causing adverse health effects in humans and wildlife by altering the function of the endocrine system. Having been very close to the center of debate on the implications of the endocrine disruptor hypothesis throughout the 1990s (I chaired a major international workshop that defined research needs in 1995 and subsequently led development of the US Environmental Protection Agency's research strategy), I have anticipated an objective historical analysis for some time. In Hormonal Chaos, Sheldon Krimsky partially satisfies my requirements as he describes the emergence of the hypothesis largely through the efforts, if not the eye, of Theo Colborn. Colborn was a late-arriving environmental scientist, having received her PhD from the University of Wisconsin in 1985 at the age of 58. By bringing together multi-disciplinary groups of scientists at so-called ‘Wingspread Conferences’, Colborn prompted the condensation of knowledge in areas of reproductive, neurological and immunological effects, wildlife biology and exposure assessment relative to the ability of chemicals present in the environment to act as hormones and, therefore, to induce a variety of effects such as birth defects, learning deficits and cancer. Similar to previous environmental health issues, where the hazard is partially understood but the true relative risks are not, the endocrine disruptor hypothesis has spawned considerable news coverage and scientific debate. Krimsky frames his task in a larger public health context, where there is an inevitable clash with the need to be protective of public health, but where the evidence is seldom conclusive to either decide that a risk is acceptable, or to judge it to be of immediate concern. The last decades of the 20th century are replete with similar stories (e.g. cyclamates, Alar, Bendectin, cellular phone use, electric power lines) but, as noted in the book, all of these pale in comparison to the potential breadth of the endocrine disruptor hypothesis. Although Krimsky's tendency to be an advocate (a term he posits to describe one of the four types of scientific accountability and responsibility), at times clouds his evaluation of the evidence, the book is, nonetheless, a relatively balanced documentary. Those very close to the field will probably find fault with certain segments of the text, but people with a general interest in environmental health protection, or those wishing to see how science is translated into regulatory policy, will enjoy the reading.Chapter 1 traces the scientific roots of the field. Beginning with the works of Rachel Carson, we are quickly led through examples of the transgenerational carcinogenicity of DES (diethylstilbestrol, a synthetic estrogen prescribed erroneously, as it later turned out, in the 1950s, to help prevent miscarriages), the declining populations of wildlife in the Great Lakes region, a meta-analysis describing a worldwide decline in sperm counts from the 1940s to the end of the 1980s, epidemiological studies that found an association between DDT exposure and elevated risks of breast cancer and the effects of polychlorinated biphenyl (PCB) on neurological development. Collectively these topics demonstrate the breadth of the public health concerns for chemicals that influence the functioning of the endocrine system. It is this blending of diverse health outcomes into a common etiology (endocrine disruption) that makes the endocrine disruption hypothesis so compelling, yet, at the same time, illustrates the magnitude of the controversy and the limitations of science. One limitation I see in the text is a tendency to consider ‘endocrine disruption’ as a health outcome that should be regulated just as we do carcinogens or teratogens. It is important to remember when reading this book that endocrine disruption is only a mode of action by which a chemical might exert an effect on health. It is the health outcomes themselves that the US Congress tells regulatory agencies such as EPA to act upon. Knowing the mode of action through which a chemical operates should help reduce uncertainties inherent in the risk assessment process, where effects must be extrapolated from high to low doses and from results obtained in experimental animals to humans, but is not an end in itself.Chapter 2 turns to the public arena and describes several US Congressional hearings, television documentaries, the creation of Our Stolen Future (a mass-market book co-authored by Colborn, published in 1996 by Dutton, New York), White House actions to coordinate governmental activities, some international activities and the actions of several non-governmental organizations (both public interest groups and industry consortia). The author also makes the point that this is the first public health issue to arise in the age of the Internet and goes on to describe how this helped fuel the issue.Chapter 3, ‘Uncertainty, Values and Scientific Responsibility’, is the heart of the book. When the endocrine disruptor issue is placed in the broader context of public health policy debate and development, one sees the challenges and limitations of the current system, and how various elements attempt to influence it. Through an analysis of book reviews of Our Stolen Future, Krimsky paints the picture of the polarizing response the hypothesis elicited in both the scientific community and the press. He touches upon such basic elements as ethical disclosure and behavior, the role of peer review in science, the precautionary principle and the value of independent replication of scientific findings. In an area where science is pushing policy and policy is pushing science, the lack of robustness of some scientific findings has placed a significant burden on the field. Although there are several examples in this area, only one was touched upon in any detail.Having set the scientific and political stage, Chapter 4 turns to the policy issues that must be confronted when the issues are complex, the science is not complete, and there is a constituency calling for action. The reader is taken through the strengths and weaknesses of using mechanistic data in risk assessment and we are shown how various sectors use such information to further their agendas. Finally, we are brought to the point where the rubber meets the road – how EPA was authorized to screen for endocrine modes of action and how the Agency proceeded to develop a consensus approach by the key stakeholders who held very divergent views.The brief final chapter summarizes the shifting paradigm from environmental concerns for cancer to one involving risks to development and reproduction and how this presents challenges to scientists and policymakers. Some readers will definitely quibble with the points made in this chapter regarding what is generally considered uncontested in the scientific community. Indeed, the National Toxicology Program recently conducted a special peer review on whether endocrine disruptors pose hazards at low exposure levels, an issue that remains controversial. Krimsky also missed an opportunity to present some balance in his analysis. He mentions the criteria of the IARC (the International Agency for Research on Cancer) in categorizing the carcinogenic risk of chemicals to humans. However, he fails to mention that the IARC recently placed atrazine, a herbicide that induces mammary tumors (and hence is identified as an endocrine disruptor) in one strain of rats but not in others or in mice, in Category III (not classifiable as a risk to humans) on the basis of mechanistic information that indicated the mode of action in the sensitive strain would not result in mammary tumors in humans. This example demonstrates that mechanistic research might either heighten our concern for the risk to humans or, as in this case, suggest that the risk is less than first perceived.A short epilogue discusses the report of the National Research Council on endocrine disruptors (Hormonally Active Agents in the Environment, 1999, National Academic Press). Here, Krimsky took the advocates’ view in assessing the output. As that committee served as microcosm for the polarized nature of the view of endocrine disruption, a more pointed analysis of the deliberations of the committee would have added to the value of Hormonal Chaos as a historical repository.