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Institute of Medicine (US) Roundtable on Environmental Health Sciences, Research, and Medicine; Goldman L, Coussens CM, editors. Environmental Health Indicators: Bridging the Chasm of Public Health and the Environment: Workshop Summary. Washington (DC): National Academies Press (US); 2004.
Environmental Health Indicators: Bridging the Chasm of Public Health and the Environment: Workshop Summary.
Show detailsMonitoring and the use of indicators are standard in many aspects of government and business practice as a means of assessing problems, developing policy, and measuring progress. Indicators communicate information about conditions, and when recorded over time, signal changes and trends. Often they signal that something more fundamental or complex is occurring than what is actually measured, which makes them useful for guiding policy and directing research (NRC, 2000).
The notion of environmental health indicators arose from the common use of economic development, such as gross domestic product, according to Tord Kjellstrom of Australian National University. Like economic indicators, they are needed because it is not possible to measure everything. Acknowledging a critical environmental health gap, the Pew Environmental Health Commission proposed in 2001 the establishment of a national tracking system to monitor environmentally related exposures and diseases (Pew Environmental Health Commission, 2001), said Thomas Burke of the Bloomberg School of Public Health. The report noted a lack of basic information on the linkages between environmental hazards and chronic disease.
CRITERIA FOR ESTABLISHING AN EFFECTIVE NATIONWIDE ENVIRONMENTAL HEALTH MONITORING SYSTEM
The fundamental issues of monitoring are the basic aspects of public health and environmental protection, and the establishment of this program should have occurred 25 years earlier, noted Burke. The concept of linking environment and health dates back to the Council on Environmental Health in the 1970s and was again noted in the Institute of Medicine (1988) report The Future of Public Health, which communicated that “the removal of environmental health authority from public health agencies has led to fragmented responsibility, lack of coordination, and inadequate attention to the health dimensions of environmental problems.” The Pew Environmental Health Commission continued the discussion and recommended that the nation's environmental health defense system be strengthened, that the environmental precursors of disease be identified and controlled, and that public health's readiness to respond be improved, noted Burke. The commission's recommendations included establishing:
- a national baseline tracking network for diseases and exposures;
- a nationwide early-warning system for critical environmental health threats;
- state pilot tracking programs to test diseases, exposures, and approaches for national tracking;
- federal investigative response capability; and
- tracking links to communities and research.
Acting on these recommendations, the Centers for Disease Control and Prevention (CDC) set up four environmental health monitoring workgroups to obtain input from those interested in working together with the agency, noted Michael McGeehin, the National Center for Environmental Health, CDC. The National Center for Environmental Health (NCEH) held three meetings in which 75 people from across the country—from the states, academic institutions, and nongovernmental organizations—worked within the workgroups to advise the CDC on the best way to set up a national monitoring system. They specified six requirements for the system; the nationwide monitoring system must:
- 1.
make sense to people in local health departments;
- 2.
be keyed to local public health actions;
- 3.
receive adequate funding over the long term;
- 4.
have a sense of stability;
- 5.
be based on sound science; and
- 6.
be linked to other federal agencies.
They also advised building the system from the “bottom up” (from state, local, and community levels).
Scientific Underpinnings of Environmental Health Monitoring
According to Burke, three recent developments are helping to provide a stronger scientific basis for monitoring activities. First, a “sound science” movement has been started with the aim of strengthening the basis for environmental decisions. Solid scientific research provides the means to assess whether a certain method works and whether public health goals have been achieved; yet calls for perfection in scientific research in this time of uncertainty could lead to difficult delays in environmental progress, noted Burke. Second, the cumulative risks of environmental exposures are beginning to be assessed, as exemplified in the Clean Air Act. Monitoring based on sound science and sound policy can help us develop better public health intervention indicators. Third, epidemiology is being revived as a means of addressing major environmental issues. Epidemiologic studies have led to progress in understanding the risks posed by methylmercury, arsenic, and particulate air pollution, among others.
Environmental Health Monitoring Priorities
Many participants noted that the currently proposed monitoring program has a number of limitations and that priorities would have to be set in order to ensure the success of the program. Burke noted that the Pew Commission identified specific components of a national monitoring system that must be built within the next few years, and these components are reflected in part in the nationwide health tracking bill before Congress. The following health outcome measures were recommended by the commission for monitoring: chronic respiratory conditions (asthma, chronic pulmonary obstructive disease), neurologic diseases, birth defects, developmental disabilities, and cancer. Environmental exposures recommended for monitoring include specific air pollutants and food and water contaminants. The commission also recommended that the capacity of the country's emergency departments and poison centers be increased to provide an early-warning system for specific environmental contamination, a measure that would benefit antiterrorism efforts. Another recommendation was to increase the laboratory capacity for biomonitoring around the country.
Burke presented an analysis of data from the National Health Interview Survey (NHIS) on potential indicators from the public health side that show dramatic increases in self-reported neurologic disorders, respiratory diseases, and endocrine and metabolic disorders over a recent 10-year period (see Figure 2.1). These increases are indicators that can be used to identify areas where more information is needed and where we must move ahead with monitoring and research.
FIGURE 2.1
The percentage of self-reported diseases increased from 1988 to 1995. Results such as these may suggest areas for future environmental health monitoring. SOURCE: National Health Interview Survey, 1995. Reprinted with permission.
Issues of Privacy in Environmental Health Monitoring
A crucial issue is balancing the need for environmental health monitoring with the need for privacy and confidentiality. The right to privacy is an issue of high interest in this country. Burke noted that our population has been served well by existing mechanisms for safeguarding privacy; these measures were questioned and put to the test when HIV prevention strategies were developed and cancer registries were created. Thus, the privacy issue should not be a stumbling block to monitoring if we build on existing mechanisms, and set the best academic minds to the task of ensuring that we move forward while respecting individual rights.
Kjellstrom suggested that studying the way other countries handle the privacy issue may help avoid negative experiences. For example, a study of the Swedish system would reveal potential ramifications because Sweden represents an extreme in monitoring systems. A number assigned to each individual at birth reveals the infant's sex, birth date, location of birth, and order of birth among all Swedes at the same location who share a birth date. The number is used later on the person's passport, driver's license, bank accounts, and health records. In New Zealand, a number also is assigned at birth, but it reveals nothing about the person. The number is used for all subsequent medical records, cancer registries, and mortality registries and can be used to link data in investigations of environmental risks, such as asbestos exposure. A system that assigns a meaningless number may raise fewer ethical problems than one that reveals information about the person, according to Kjellstrom. Public health research that tracks data for individuals by number creates ethical responsibilities for researchers. However, failing to study the health effects of a possible risk factor also poses ethical issues.
ENVIRONMENTAL HEALTH INDICATORS
The cornerstone of an environmental health monitoring effort is the selection of indicators. Although the participants did not discuss which indicators should be selected, they did discuss the definition of indicators; the identification of indicators, including the components of environmental health monitoring; and the process and criteria for the selection of indicators.
Definition of Environmental Health Indicators
Several organizations have crafted comprehensive definitions of environmental health indicators. The National Association of County and City Health Officials (NACCHO) has called them “tools for quantifying, through direct or indirect measures, a significant aspect of an environmental health issue,” which “can be used to assess and communicate the status of and trends in overall environmental health” (NACCHO, 2000).
A definition of an environmental health indicator, developed by the World Health Organization (WHO) and others, is that it “provides information about a scientifically based linkage between environment and health”; thus, “an indicator which purely describes the state of the environment or a pure health status indicator with no obvious link to environmental causation, cannot be considered an environmental health indicator.” The term environmental health indicator “implies monitoring and action” (Kjellstrom and Corvalan, 1995).
According to the Council of State and Territorial Epidemiologists (CSTE), “Environmental public health indicators provide information about a population's health status with respect to environmental factors. Core indicators can be used to measure health or a factor associated with health such as a risk or intervention in a specified population” (CSTE, 2001). Burke suggested that indicators are tools that can be direct or indirect measures.
Identifying Environmental Health Indicators
Burke suggested several criteria for a useful environmental health indicator. The indicator must be:
- simple—measure only one item;
- measurable—comparable and quantifiable;
- understandable—comprehensible to policy makers and the public; and
- defensible—support a relationship between environmental factors and health status.
The term “environmental indicator” implies an association, or a suggestion of an association, between a factor and an outcome. Some participants speculated about how broad a view should be taken about which kinds of outcomes are “suitable” for environmental health indicators. Should only those outcomes be used for which there is a proven association with an environmental hazard? Alternatively, should outcomes or linkages be considered that have not yet been proven conclusively, but for which there are possible associations? Burke suggested that a true indicator should have an association and/or should indicate the presence of a risk, but we must not be too narrow in our focus because “perfectionism is sometimes the enemy of progress.” The issue is whether our goal is prevention and precaution or proof because they are fundamentally different. In environmental public health, indicators are essential for understanding risk and evaluating interventions.
William Pease of GetActive Software suggested that an environmental health indicator also must be credible, relevant, and able to be acted on. Because complete information is lacking in vast areas of environmental health, we must be realistic about the credibility we can expect from the indicators that we provide to the public, noted Pease. Scientists working with environmental health indicators tend to place a high value on establishing clearly the entire causal chain from source to effect. Because this amount of information is seldom available, we must learn how to accept statements as credible in the absence of full information. If we take a rigorous, science-based approach to environmental health indicators, we risk missing information critical to assessment. The scope of environmental problems and the activities that generate adverse environmental consequences require a large number of indicators.
Another aspect of credibility involves the role of the entity that develops and promotes the indicator, its so-called social status. Indicators have to be viewed as objective, or at least science-based, and not distorted by any conflict of interest, in order to engender trust, noted Pease. In many cases, environmental organizations or other nongovernmental organizations may be in a better position than federal regulatory agencies to produce environmental health indicators that are trusted.
A trade-off may be needed between having core indicators that are valuable nationally, and even internationally, and having indicators that are relevant to local needs, noted Burke. Identifying the indicators that will allow health and environmental health officials and regulatory agencies to better understand the environmental risk at the local level is a particular challenge. A national exposure report, such as the one being compiled by the CDC on chemical exposures, provides a profile for the nation but may reveal little about risks in a particular region—for example, the risk of mercury exposure by women of childbearing age near the Chesapeake Bay who consume contaminated fish from areas with closures and advisories.
Components of Environmental Health Monitoring and Corresponding Indicators
Environmental health monitoring has three major components: hazard monitoring, exposure monitoring, and health outcome (health effects) monitoring. Each component has corresponding indicators—hazard indicators, such chemical spills, and motor vehicle emissions; exposure indicators, such as blood lead level in children; and health outcome (health effects) indicators, such as pesticide-related poisoning in children, and melanoma. A step beyond these three indicators is the intervention indicator. Examples of intervention indicators are laws pertaining to smoke-free indoor air, boil-water advisories, and alternative fuel use in motor vehicles.
As a nation, we have been quite successful at hazard monitoring, and legislation has pushed us to identify sources and potential routes of exposure, stated Burke. The work of the Environmental Protection Agency (EPA), exemplified in the EPA inventories, regulatory programs, and monitoring programs, has helped illuminate and, to a certain extent, control environmental hazards. We have not been as successful with exposure tracking, although we have made some progress recently with the National Report on Human Exposure to Environmental Chemicals (CDC, 2003), a CDC effort to monitor national exposure to a range of environmental toxicants. This report will be a cornerstone of the new monitoring-based approach to environmental health. However, the report is still in its infancy, and the tools it describes are not yet available for use by the public health and environmental health communities to help with outcome monitoring.
INTERNATIONAL FRAMEWORKS FOR DEVELOPING ENVIRONMENTAL HEALTH INDICATORS
In the early 1990s, the Organization for Economic Co-operation and Development (OECD) published its Pressure-State-Response (PSR) framework to promote a common set of “environmental performance indicators.” Many indicators provide an easily interpretable measure of the state of the environment or the health of a defined population. Examples are urban air quality variables and life expectancies of populations. These “one-dimensional” indicators have been widely adopted internationally and are important for describing time trends and geographic variations. According to Kjellstrom, U.S. government agencies, academic institutions, industry, and other interested parties have been active in developing such indicators. However, creating indicators that can be interpreted in terms of linkages between environmental quality and public health has been a major challenge.
A series of activities was begun in 1992 at the World Health Organization to establish a method for how such indicators could be developed and tested. A new framework, the DPSEEA framework, was devised that incorporates transparent linkages between various one-dimensional environment or health indicators and places the focus on public health. DPSEEA stands for Driving force-Pressure-State-Exposure-Effect-Action. Numerous case studies have shown that this framework is helpful in developing indicators. Indicators at all levels in the DPSEEA framework could apply locally, nationally, or internationally, depending on the context. According to Kjellstrom, this framework has the potential to “bridge the chasm between public health and the environment.”
The character of the environmental health problem defines the level of the policy decision. Kjellstrom gave an example of how, in New Zealand, a ban on burning coal is a local issue, and no decision is involved at the national level. In contrast, the ban on lead in gasoline required a national decision because New Zealand has only one oil refinery. Some issues, such as global climate change, must be dealt with at the international level.
In New Zealand and Australia, there has been interest in a core environmental health indicators list. However, such an approach may be unproductive because each community has its own concerns. As long as a nation does not commit to some “magical” core national set of indicators, without responding to the needs and concerns of individual communities, progress will be made.
Kjellstrom has concluded that the ultimate environmental health indicator would be the number of people affected by a specific environmental hazard. The Ministry of Transport in New Zealand recently used such an indicator—the number of fatalities from vehicle-related air pollution in the country (annually estimated at 400)—as an argument for better-quality fuels, better testing of vehicle emissions, and the use of catalytic converters. A related indicator is the number of “obesogenic” car-related deaths, that is, deaths caused by environmental factors that create obesity. Tentative estimates for the city of Auckland, New Zealand, indicated that the number of such deaths related to lack of daily physical activity because of car use instead of “active transport” could be at similar levels as the numbers of car crash deaths (annually estimated at 40). Kjellstrom suggested that this indicator would be particularly relevant to the United States, where the dramatic rise in obesity rates in recent years may be strongly related to environmental factors, such as increased driving time, decreased exercise, and greater availability of high-calorie fast food.
USING INDICATORS TO RANK ENVIRONMENTAL HEALTH RISKS
In the United States, the EPA and the Office of Science and Technology Policy (OSTP) have been grappling with prioritizing risks and ensuring public participation, said Baruch Fischhoff of Carnegie Mellon University. OSTP has called for an approach to risk prioritization that is scientifically sound, understandable to the public, comparable across programs and agencies, and cumulative so that it produces a predictable record over time.
Creating a scientifically sound method of ranking environmental health risks that includes public input involves first establishing criteria for the content of environmental health indicators and then selecting criteria for the risk prioritization process, noted Fishhoff. Subsequently, five steps must be taken, as shown in Figure 2.2.
FIGURE 2.2
Five steps that have to be used to identify risk ranking for prioritizing environmental health indicators. SOURCE: Florig et al., 2001. Reprinted with permission.
According to Fischhoff, risks must be defined and categorized. Care must be taken not to create categories so small that none draws people's attention or so large that they do not lend themselves to common monitoring or action. The indicators must have four attributes: (1) They should be a reflection of people's values regarding the environment and their health. (2) The best science available should be used to describe the risks in terms of these attributes, and a process of ranking the risks should be established. (3) The ranking should be conducted through a democratic, participatory process by people who have a good understanding of the issues. (4) The results should be communicated in a usable and understandable form.
Fischhoff further suggested that each indicator should be explicitly defined so that it is understood by the public. The definition should reflect underlying scientific findings and any uncertainty associated with the indicator. The results of the ranking should be arranged to allow easy comparisons. Communicating the results should be a joint editorial undertaking to ensure that the science is solid, the language is comprehensible, the style is fluent, and legal issues are taken into account.
Summary of Environmental Health Monitoring and Indicators
During the workshop, speakers and panelists used many definitions to help describe what environmental health monitoring is, the definition of an indicator, and what the selection criteria are. The first call for environmental health monitoring occurred more than 25 years ago. The Institute of Medicine (1988) questioned the removal of environmental health authority from public health agencies, which led to a lack of coordination and inadequate attention to the health dimensions of environmental problems; the Pew Environmental Health Commission (Environmental Health Tracking Project Team, 2000) further recommended that the nation's environmental health defense system be strengthened, reinforcing the basic need for environmental health to respond to a myriad of health challenges.
Speakers further suggested that the currently proposed monitoring program has a number of limitations and that priorities would have to be established to ensure its success. This has led to many individuals and organizations to lay the groundwork for the program, by defining what the program would include and defining what environmental indicators are.
According to some speakers, environmental health indicators are tools for quantifying the scientific linkage between environment and health. They must be:
- simple—one item;
- measurable—comparable, quantifiable, and rankable;
- defensible;
- understandable—able to access information in a usable form;
- credible—“unbiased source,” best science;
- comprehensible;
- actable;
- responsive to local needs; and
- reflective of societal values on environment and health.
Footnotes
- *
This chapter was prepared by staff from the transcript of the meeting. The discussions were edited and organized around major themes to provide a more readable summary and to eliminate duplication of topics.
- Overview of Environmental Health Monitoring and the Use of Indicators - Environm...Overview of Environmental Health Monitoring and the Use of Indicators - Environmental Health Indicators
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