- Email: [email protected]
Social, Economic and Cultural Context Influence the Expression of Exposure to Neurotoxicants: Session IV Summary and Research Needs
NeuroToxicology 22 (2001) 559±561
Social, Economic and Cultural Context In¯uence the Expression of Exposure to Neurotoxicants: Session IV Summary and Research Needs Bernard Weiss1,*, John Peterson Myers2 1
Department of Environmental Medicine, School of Medicine & Dentistry, University of Rochester, 575 Elmwood Ave., Box EHSC, Rochester, NY 1462, USA 2 W. Alton Jones Foundation, Charlottesville, VA, USA
SESSION SUMMARY With so much public attention directed at children's needs, it is inevitable that the science bearing on threats to child development will intersect the corresponding policy issues. Session IV was organized to offer some perspectives on how these issues shape the role of scienti®c research in the arena of neurotoxicology. It was meant to convey the importance of viewing neurotoxic risks to child development in much broader perspective than chemical agents alone. Exposure and response take place in variable settings with unique characteristics that have to be considered in risk formulation. WHY SOCIAL, ECONOMIC AND CULTURAL INFLUENCES COUNT Bernard Weiss As scientists, we have a natural af®nity for clean, elegant conclusions con®ned to data stripped as much as possible of ambiguity. But we practice science in a social, economic, and cultural milieu that simultaneously limits and enlarges our data-bound conclusions and interpretations. Neurotoxicology, because it is so intimately joined to public concerns, is more * Corresponding author. Tel.: 1-716-275-1736; fax: 1-716-256-2591. E-mail address: [email protected] (B. Weiss).
deeply embedded in this milieu than most other disciplines. This Session was an attempt to illuminate this wider context, and to express the inevitable commingling of science and extra-science that results. It explored the cultural determinants of exposure and response, the economic assumptions that guide responses to risks, the political nuances of scienti®c debates, the legitimacy of proof in epidemiology, and how the new technologies of information acquisition and dispersion can in¯uence the de®nition of and response to risk. ASSESSING THE INFLUENCE OF CULTURAL PRACTICES ON POPULATION RESPONSES TO NEUROTOXIC EXPOSURES Elizabeth Guillette Dr. Guillette presented the point of view of an anthropologist, drawing upon her experience in studying communities in Mexico that have adopted different approaches to the use of chemical agriculture. She noted that anthropologists ®rst embed themselves in a society so that they are not simply outsiders looking in, and argued that investigators need to understand the enormous diversity of social and cultural practices that help determine how different groups respond to their environments. She also discussed the ways in which anthropologists index and describe cultural variables and the differences with conventional indices of child development.
0161-813X/01/$ ± see front matter # 2001 Published by Elsevier Science Inc. PII: S 0 1 6 1 - 8 1 3 X ( 0 1 ) 0 0 0 7 0 - 5
560
B. Weiss, J.P. Myers / NeuroToxicology 22 (2001) 559±561
COSTS, BENEFITS, AND THE METRICS OF RISKS Penny Schafer Dr. Schafer discussed the topic of bene®t-cost analysis, which is widely used in the adoption of environmental regulations. As an economist, she emphasizes the view that for every bene®t there is a cost, and that what scientists contribute is the information required to enter into the equation. Dr. Schafer also provided a short summary of economic principles, such as discounting, or the diminution in present value over time. Put another way, economists typically apply some selected percent annual ``discount rate'' to convert future regulatory costs and bene®ts into their ``present value''. She also discussed the techniques economists use to extract a monetary value from certain actions, for example using willingness to pay as a metric for avoiding a certain adverse effect. STANDARDS OF PROOF IN ENVIRONMENTAL EPIDEMIOLOGY John Peterson Myers Dr. Myers, basing his discussion on endocrine disrupting chemicals, argued that epidemiology is not equipped to answer the question of whether they exert any impacts on human health. The problem is that it is biased towards ®nding false negatives due to ®ve speci®c barriers. First, it assumes monotonic dose± response relationships although, for endocrine disruptors as well as for other chemicals, the function may be U-shaped or J-shaped, so that low or high exposures but not intermediate ones may exert adverse effects. Second, it cannot easily incorporate the timing of exposure, especially in dealing with developmental effects, for which timing is crucial. Third is the problem of extended delays between exposure and its toxic expression, a special challenge for developmental neurotoxicity. Fourth, the in¯uence of endocrine disruptors cannot be studied in isolation both because they occur as ingredients in a sea of chemicals with which they interact in complex ways and because, due to their ubiquitous distribution, no control populations are available. Finally, the endpoints are not identi®able as rare cases of a disease, but instead, phenomena such as lowered IQ scores, lowered sperm counts, and other deviations from the norm. Epidemiology deals well with changes in frequency of rare events but variations from the mean in common endpoints are
less likely to be detected. Together these ®ve barriers pose signi®cant challenges to epidemiology in avoiding false negatives in studies of endocrine disruption in people. CASE HISTORY OF CHLORPYRIFOS UNDER FQPA: A YEAR 2000 REPORT Cheryl Cleveland and George R. Oliver Dr. Cleveland presented a perspective on chlorpyrifos essentially as a bene®t-risk case study. Chlorpyrifos, like other pesticides, plays an important economic role in agriculture and is also seen to provide health bene®ts because of its use in controlling the spread of disease and because it helps make food cheaper and more readily available. Like other pesticides, it is closely regulated as well, with a substantial margin of safety for residues found in foods. A number of EPA policy decisions have led to the virtual elimination of chlorpyrifos for residential uses, however, including the 10-fold provision of the Food Quality Protection Act. POLITICAL UNDERCURRENTS OF ENDOCRINE DISRUPTION Sheldon Krimsky In his recent book, Hormonal Chaos, Dr. Krimsky provided a history of how the issue of endocrine disruptors had emerged as both a scienti®c and policy issue. In presentation at this conference, he traced its history from its beginnings as a topic that engaged curious scientists from different specialties to a question that spread itself across a broad landscape populated not only by scientists but by a variety of stakeholders in government and industry. The media at ®rst paid little attention, but gradually began to notice the rising volume of concern and to devote more space and resources to the story. Some elements of industry perceived signi®cant dangers from these discussions and engaged various consultants in a counteroffensive. Newspaper stories show the depth and extent of these measures. INFORMATION AS A RISK VARIABLE Bernard Weiss Dr. Weiss argued that comparative risk exercises are typically conducted by a panel or committee that
B. Weiss, J.P. Myers / NeuroToxicology 22 (2001) 559±561
is convened to achieve consensus about risk rankings based on exposure and toxicological data. Agreement is sought because uncertainty is the common ingredient in risk assessment. This process tends to neglect two other major components of uncertainty. One is the degree of variability or disagreement among the raters because the process is designed to eliminate it. The other is the degree of uncertainty held by the raters. Current information technologies lend themselves to enhancements of the process. By using these technologies, it is possible to exploit these electronic resources, such as the World Wide Web, to survey a much wider group of experts or even community members, so that a much more representative index of opinion can be elicited. Such a survey also provides a measure of disagreement, an important tool for policy. In addition, by securing self-assessments of con®dence not limited by the usual committee social structure, policy makers can balance risk rankings or rankings with this critical measure of certainty. Translating such surveys into ``fuzzy logic'' terms confers additional analytical possibilities. An example of how a risk exercise could be conducted was shown; it was based on software developed at the University of Rochester.
561
RESEARCH NEEDS 1. Social and cultural determinants of exposure need investigation. Usually, exposure is studied in isolation, but cultural practices such as child-rearing patterns may markedly modify exposure variables and their consequences. 2. Specialists in neurotoxicology and in economics should undertake collaborations. Economists use various techniques to monetize risks, but risks expressed as neurobehavioral toxicity offer unique difficulties that need to be addressed by collaborations between the two disciplines. 3. Detailed prospective studies such as those conducted for the assessment of lead toxicity should be undertaken to gauge the neurodevelopmental risks posed by endocrine disruptors. Conventional epidemiology is poorly equipped to deal with issues such as delayed and silent toxicity. 4. The new information technologies should be exploited to obtain a better grasp of the variability among both expert and lay groups in how they rate various risks and the corresponding degree of uncertainty about those ratings. Confining such exercises to committees charged to achieve consensus produces misleading risk characterizations.
Social, Economic and Cultural Context In¯uence the Expression of Exposure to Neurotoxicants: Session IV Summary and Research Needs Bernard Weiss1,*, John Peterson Myers2 1
Department of Environmental Medicine, School of Medicine & Dentistry, University of Rochester, 575 Elmwood Ave., Box EHSC, Rochester, NY 1462, USA 2 W. Alton Jones Foundation, Charlottesville, VA, USA
SESSION SUMMARY With so much public attention directed at children's needs, it is inevitable that the science bearing on threats to child development will intersect the corresponding policy issues. Session IV was organized to offer some perspectives on how these issues shape the role of scienti®c research in the arena of neurotoxicology. It was meant to convey the importance of viewing neurotoxic risks to child development in much broader perspective than chemical agents alone. Exposure and response take place in variable settings with unique characteristics that have to be considered in risk formulation. WHY SOCIAL, ECONOMIC AND CULTURAL INFLUENCES COUNT Bernard Weiss As scientists, we have a natural af®nity for clean, elegant conclusions con®ned to data stripped as much as possible of ambiguity. But we practice science in a social, economic, and cultural milieu that simultaneously limits and enlarges our data-bound conclusions and interpretations. Neurotoxicology, because it is so intimately joined to public concerns, is more * Corresponding author. Tel.: 1-716-275-1736; fax: 1-716-256-2591. E-mail address: [email protected] (B. Weiss).
deeply embedded in this milieu than most other disciplines. This Session was an attempt to illuminate this wider context, and to express the inevitable commingling of science and extra-science that results. It explored the cultural determinants of exposure and response, the economic assumptions that guide responses to risks, the political nuances of scienti®c debates, the legitimacy of proof in epidemiology, and how the new technologies of information acquisition and dispersion can in¯uence the de®nition of and response to risk. ASSESSING THE INFLUENCE OF CULTURAL PRACTICES ON POPULATION RESPONSES TO NEUROTOXIC EXPOSURES Elizabeth Guillette Dr. Guillette presented the point of view of an anthropologist, drawing upon her experience in studying communities in Mexico that have adopted different approaches to the use of chemical agriculture. She noted that anthropologists ®rst embed themselves in a society so that they are not simply outsiders looking in, and argued that investigators need to understand the enormous diversity of social and cultural practices that help determine how different groups respond to their environments. She also discussed the ways in which anthropologists index and describe cultural variables and the differences with conventional indices of child development.
0161-813X/01/$ ± see front matter # 2001 Published by Elsevier Science Inc. PII: S 0 1 6 1 - 8 1 3 X ( 0 1 ) 0 0 0 7 0 - 5
560
B. Weiss, J.P. Myers / NeuroToxicology 22 (2001) 559±561
COSTS, BENEFITS, AND THE METRICS OF RISKS Penny Schafer Dr. Schafer discussed the topic of bene®t-cost analysis, which is widely used in the adoption of environmental regulations. As an economist, she emphasizes the view that for every bene®t there is a cost, and that what scientists contribute is the information required to enter into the equation. Dr. Schafer also provided a short summary of economic principles, such as discounting, or the diminution in present value over time. Put another way, economists typically apply some selected percent annual ``discount rate'' to convert future regulatory costs and bene®ts into their ``present value''. She also discussed the techniques economists use to extract a monetary value from certain actions, for example using willingness to pay as a metric for avoiding a certain adverse effect. STANDARDS OF PROOF IN ENVIRONMENTAL EPIDEMIOLOGY John Peterson Myers Dr. Myers, basing his discussion on endocrine disrupting chemicals, argued that epidemiology is not equipped to answer the question of whether they exert any impacts on human health. The problem is that it is biased towards ®nding false negatives due to ®ve speci®c barriers. First, it assumes monotonic dose± response relationships although, for endocrine disruptors as well as for other chemicals, the function may be U-shaped or J-shaped, so that low or high exposures but not intermediate ones may exert adverse effects. Second, it cannot easily incorporate the timing of exposure, especially in dealing with developmental effects, for which timing is crucial. Third is the problem of extended delays between exposure and its toxic expression, a special challenge for developmental neurotoxicity. Fourth, the in¯uence of endocrine disruptors cannot be studied in isolation both because they occur as ingredients in a sea of chemicals with which they interact in complex ways and because, due to their ubiquitous distribution, no control populations are available. Finally, the endpoints are not identi®able as rare cases of a disease, but instead, phenomena such as lowered IQ scores, lowered sperm counts, and other deviations from the norm. Epidemiology deals well with changes in frequency of rare events but variations from the mean in common endpoints are
less likely to be detected. Together these ®ve barriers pose signi®cant challenges to epidemiology in avoiding false negatives in studies of endocrine disruption in people. CASE HISTORY OF CHLORPYRIFOS UNDER FQPA: A YEAR 2000 REPORT Cheryl Cleveland and George R. Oliver Dr. Cleveland presented a perspective on chlorpyrifos essentially as a bene®t-risk case study. Chlorpyrifos, like other pesticides, plays an important economic role in agriculture and is also seen to provide health bene®ts because of its use in controlling the spread of disease and because it helps make food cheaper and more readily available. Like other pesticides, it is closely regulated as well, with a substantial margin of safety for residues found in foods. A number of EPA policy decisions have led to the virtual elimination of chlorpyrifos for residential uses, however, including the 10-fold provision of the Food Quality Protection Act. POLITICAL UNDERCURRENTS OF ENDOCRINE DISRUPTION Sheldon Krimsky In his recent book, Hormonal Chaos, Dr. Krimsky provided a history of how the issue of endocrine disruptors had emerged as both a scienti®c and policy issue. In presentation at this conference, he traced its history from its beginnings as a topic that engaged curious scientists from different specialties to a question that spread itself across a broad landscape populated not only by scientists but by a variety of stakeholders in government and industry. The media at ®rst paid little attention, but gradually began to notice the rising volume of concern and to devote more space and resources to the story. Some elements of industry perceived signi®cant dangers from these discussions and engaged various consultants in a counteroffensive. Newspaper stories show the depth and extent of these measures. INFORMATION AS A RISK VARIABLE Bernard Weiss Dr. Weiss argued that comparative risk exercises are typically conducted by a panel or committee that
B. Weiss, J.P. Myers / NeuroToxicology 22 (2001) 559±561
is convened to achieve consensus about risk rankings based on exposure and toxicological data. Agreement is sought because uncertainty is the common ingredient in risk assessment. This process tends to neglect two other major components of uncertainty. One is the degree of variability or disagreement among the raters because the process is designed to eliminate it. The other is the degree of uncertainty held by the raters. Current information technologies lend themselves to enhancements of the process. By using these technologies, it is possible to exploit these electronic resources, such as the World Wide Web, to survey a much wider group of experts or even community members, so that a much more representative index of opinion can be elicited. Such a survey also provides a measure of disagreement, an important tool for policy. In addition, by securing self-assessments of con®dence not limited by the usual committee social structure, policy makers can balance risk rankings or rankings with this critical measure of certainty. Translating such surveys into ``fuzzy logic'' terms confers additional analytical possibilities. An example of how a risk exercise could be conducted was shown; it was based on software developed at the University of Rochester.
561
RESEARCH NEEDS 1. Social and cultural determinants of exposure need investigation. Usually, exposure is studied in isolation, but cultural practices such as child-rearing patterns may markedly modify exposure variables and their consequences. 2. Specialists in neurotoxicology and in economics should undertake collaborations. Economists use various techniques to monetize risks, but risks expressed as neurobehavioral toxicity offer unique difficulties that need to be addressed by collaborations between the two disciplines. 3. Detailed prospective studies such as those conducted for the assessment of lead toxicity should be undertaken to gauge the neurodevelopmental risks posed by endocrine disruptors. Conventional epidemiology is poorly equipped to deal with issues such as delayed and silent toxicity. 4. The new information technologies should be exploited to obtain a better grasp of the variability among both expert and lay groups in how they rate various risks and the corresponding degree of uncertainty about those ratings. Confining such exercises to committees charged to achieve consensus produces misleading risk characterizations.