Health and environment analysis for decision making / Carlos Corvalán and Tord Kjellström

Health and environment analysis for decision making· Carlos Corvalana & Tord Kjelfstrornb Introduction The aim of the Health and Environment Analysis for Decision-making Project (HEADLAMP) is to provide valid and useful information on the local and national health impacts of environmental haz- ards to decision-makers, environmental health pro- fessionals and the community. HEADI..AMP com- bines methodologies in environmental epidemiol- ogy. human exposure assessment and other health and environmental sciences to produce and anal- yse data and present the resulting information so that it can be understood, interpreted and acted upon by those responsible · for environmental health protection. The information created via lo- cal and national HEADI..AMP applications will help monitor progress towards sustainable devel- opment as recommended in Agmd4 21 (1). The important tools in HEADLAM:P are health and environment data linkage methods, environmen- tal health indicators used to quantify and monitor the local situation, and the interpretation and deci- sion-making process. This article gives an overview of the HEAD- lAMP project and its background, while other re- ports in this issue of the World health statistics quarter- ly present further details on HEADl.AMP methods, field studies examples, the development and use of environmental health indicators and the decision making-process, based on materials discussed at the first expert meeting on HEADLAMP held in Geneva, in August 1994. The health and environment situation Air, water, soil and food contamination -whether short-term at high levels or long-term at lower lev- els- have been associated with increases in morbid- ity and mortality. However, because levels of gener- al environmental pollution fluctuate, and various extraneous determinants exist, precise measures of the association between pollution levels and health outcomes are rare. Exposure to environmental pol- lution is usually involuntary and people are often ignorant of its possible effects and therefore may exert little control over it. a Scientist, Office of Global and lnregrated Environmental Health , Wo rld H.ealut Organizatjon, Ceneva. b Director, OAice of Cl<,hal MHi Integrated E.nvironrnencal Health, World Heal th Organit.ation, Geneva. Wid hlth statist. quJt1., 48 (1995) Biological and chemical agents in the environ- ment contribute to millions of premature deaths and hundreds of millions of disabilitie5 every year (2). Certain environmental hazards affect very large populations. In many large cities millions of people are exposed to severe outdoor air pollu- tion. In addition, indoor air pollution is a wide- spread and serious problem particularly in devel· oping countries. The disease burden of indoor and outdoor air pollution is such that hundreds of mil- lions of people are affected by respiratory diseases (2). Although these estimates are very approximate - since the methodology is poorly developed and the data quality uncertain -they highlight the need to control harmful exposure. Health and environment analysis for decision- making- and data linkage where relevant- may be particularly important for those less-developed countries in which environmental pollution issue5 have traditionally taken second place to economic development issues. In many of these countries environmental pollution is increasing and popula- tions are growing, particularly in urban centres. Since governments are beginning to appreciate the links between economic growth and environ- mental protection, an estimate of health impact attributable to environmental pollution may allow decision-makers to prevent irreversible and costly health and environmental damage. Various epidemiological studies have been un- dertaken, mostly in developed countries, to link specific forms of environmental pollution and health-outcome data. The methods used, however, are not always easily applicable to other settings, especially if high quality data are unavailable. A serious limitation in conducting these studies con- cerns the measurement of exposure in individuals. Routine monitoring provides average exposures for geographical regions, and all persons within the relevant area are assumed to have exposure! that are close to the average exposure. Lack of individual exposure data, and the limitations of routinely collected health and environment data, means that the most feasible linkage is based on the "ecological" method, for which the statistical unit of observation is a population rather than an individual (3). The World Health Organization {WHO) has developed environmental qualiLy guidelines for dif- ferent pollutants in air, water, food, ~oil and the workplace ( 4-12). These guidelines are based on 71 FliJ; 1·: . The. environmental health hazard pathway: conceptual framewortc at the individual level Chaine des rlsques pour Ia sant6 116s A l'envlronnement sch6ma th6orique au niveau lndividuel TradltiOIIII hazards- Rtsqun tradHlonneta Human actMtlei - Actlvlt6s humalnes Natural phenomena - Phdnom6nes naturels Modem llazards- Risqan ROUVIIII Development activities- Actlvit6s li6tls au d~eloppement levels around an individual can be measured by using personal monitors. However, it is often the case that measurements are based on samples which provide averages (e.g., of geographical areas) , not on actual individual exposure. There- fore, the existence of a measurable amount of con- centration of a pollutant, even when higher than recommended levels, is not always sufficient infor- mation to infer health effects. The joint use of health and environmental data, plus data linkage where feasible, is essen tial for the management of known environmental health problems, such as those described above. 74 Dsvs/oplng nsw analysis and intsrprstat/on tooll" Two important criteria must be considered when developing new methods for linking health and environment data, or assessing and adapting exist- ing· ones. On the one hand the methods must be simple, inexpensive to implement and operable with available data, thus allowing rapid assessment. On the other, they must be unbiased and produce results that agree with those obtained from more detailed studies, for which the statistical precision can be quantified. Accuracy is of the greatest im- portance, since credible results are indispensa~le for promoting appropriate action. If the metho'ds are overly complex, requiring extensive resources and large amounts of additional data collection, few of the less-developed countries will be able to apply them. · HEADI.AMP methods are generally based on routinely collected data and, where relevant, on data collected from specifically designed rapid sur- veys·. Therefore, even with some control for extra- neous determinants, these methods should not be seen as substitutes for epidemiological linkages performed at an individual level. As in many other environmental epidemiology projects, the long- term challenge is to develop new forms of study design and data analysis techniques for environ- mental epidemiology. Nevertheless, much can be achieved for deci- sion-making purposes through careful application of exiSting methods. In addition, researchers in countries where no studies have been performed should be encouraged and supported in undertak- ing epidemiological studies that would help to shed light on the effects of specifk forms of envi- ronmental pollution in their particular settings. If detailed information on the dose-response re- lationship of pollutants in different settings around the world were available, techniques of risk analysis could be used to estimate the impact of exposure on different populations. This implies knowledge about exposure, estimates of the popu- lation exposed and of the health effects associated with the exposure in the form of a dose-response function. At present, this is only possible by extrap- olating from available study results done in one country (often developed) to other countries (of- ten less developed), or by using the limited num- ber of studies available from developing countries. In addition, this can be done only with respect to pollutants for which well researched exposure-re- sponse relationships have been established. One of the limitations of this approach is that background exposure levels and the dist.ributi.on of extraneous determinants may differ between populations. A more serious concern is the lack of certainty re- garding the assumed association between environ- mental pollution levels and actual exposure in in- dividuals. In addition there is a significant time lag Rapp. trimest. statist. sanit. mond., 48 (1995} between exposure and health effects for many po~ lutants. This means that the health outcomes o}). served at present may be due to exposures which occurred many years or even decades earlier. Nevertheless, in spite of these limitations, risk anal- ysis may be the only tool available for estimating the health outcomes of environmental pollution in areas where health monitoring is not undertaken, or for which data quality is poor, or for obtaining crude estimates of health impacts in very large population groups. Establishing snvlronmsntal hsalth indlcatot7r To monitor progress in environmental health management and to quantify the health impacts, at both local and national levels, it is importarit to establish an appropriate set of environmental health indicators based on health and environ- ment monitoring dat;a, and data linkage analysis. The key aspect of an indicator is the transition from "data" to "information". In this context en- vironmental health indicators can be understood as synthesized information regarding known envi- ronment-related diseases or contaminants with known adver3e health effects. Once identified, these indicators can be used to establish improved and more cost-effective environmental monitoring and management programmes. Data linkage methods and development of envi- ronmental health indicators can be very useful tools for policy making and management. Reduc- tion of exposure requires invesunent by people and authorities, and given the shortage of resourc- es for essential development activities in virtually all countries, this invesbnent can only occur if sound information is available to support it Data linkage and the development of indicators can pro- vide decision makers with tools for monitoring en- vironmental health problems and assessing the ef- fect of their policies. ThB HEAOLAMP process The project has 3 defining characteristics which differentiate it from ad hoc epidemiological studies. 1. HEADLAl\fP is based on already known and scientifically established relationships between environmental exposure and health effects. Based on these relationships it is possible to define environmental health indicators, which within the context of HEADlAMP are chosen for their potential value in the decision-making process. Research to establish new relationships between exposure and health effects is a related but separate activity. 2. The environmental health indicators used in HEA.Dl.AMP are usually based on routinely- collected data. This is cost-effective and encour- Wid hlth statist. quart., 48 (1995) ages improved use of these data and· provides guidance for more useful and valid future data collection. To measure the relevant environ· mental health indicators it may also be nece!- sary to collect new data In these situation~ HEADIAMP will encourage the use of appro! priate, low-cost techniques. 3. The ultimate aim of HEAD LAMP and its envi- ronmental health indicator! is to obtain infor- matiort on which to base preventive action against environmental health problenis. HF.AI)~ is ijltended to be an ongouig activity focusing on information n-reds at local and national levels. On-going assessment will indicate environmental health trends, and' en- able policy-makers and managers to assess the value and· performance of their policies over tirne. National and local capacity-building is,. therefore, also an integral part of the HEAD- LAMP approach. Based on these characteristics, a framework for implementing HEADLAMP in the field has been developed and is summarized in Fig. 2. Application of HEAD lAMP meth~ds is motivated by concern regarding specific environmental conditions and their potential adver3e impact on human health. In practice, application of the HEADLAMP process follows 3 stages, reflecting the 3 characteristics d& scribed above. The first stage of the process is the definition and validation of the problem. The known links between a defined environmental factor and its associated health outcomes provide the starting point. These links will already have been estab- lished in previous research and in the literature. Basic information requirements are identified at this stage. At the second stage (application/assessment and quantification environmental health indica- tors), detailed specifications for data are identified based on the specific setting, taking into account that "ideal" data will not always be available. Rou- tinely-collected data, and when necessary, specifi- cally designed rapid survey data, are then analysed to obtain information on environmen tal health effects or conditions. The variables produced through this process are the environmental health indicators. Depending on the problem and/ or fea- sibility of obtaining all the relevant data, environ- mental health indicators will be derived from: health data (e.g., morbidity rates attributable to definable environmental factors); environmental data (e.g., pollution levels with human health implications); or data linkage (e.g., time-series analyses). At the third stage (policy formulation/imp!~ mentation), policy action is taken based on the levels and trends of the environmental health indi- cators. Repeated assessments may be undertaken at appropriate intervals in order to monitor changes 75 Af;2' The HEAOLAMP Process - Processus HEAOLAMP Environmental factllrs - Facteurs liM l l'envlronnement • Relallontlllll - RtiiiiOII t Health tae1Drs - Facteurs sanltalres MOIIHIIflnt- Sl~lllance contln•-- Cootoundtr dafl.; Oonn4es sur let flctiilrs . : de confusion Demoorallhle dam- Oonntes d6mograJ)hlques . - Health - santt Environment- Envtronnement Definition/validation- D6ftnltlon/valldatlon SUrwya-~ultel Application/assessment and quantification or ascertainment of envtronl'l18frtal health Indicators - AppllcatloniMiuation et mesure ou v6rlflcallon des lndlcateurs dela salubl'ltt de l'erivlronnement Polley formulation/ implementation - Elaboratlonlmlse en oeuvre de Ia polillque in health and/or environmental status and to as- certain if any particular trend has been established. Thus, repeated assessment would contribute to monitoring the effects of policy implementation, provide support for changes in policy, and convey environmental health information to the public and other stakeholders. A decision to cease moni- toring activities may be taken once pre-set targets have been met on a sustained basis. The application of HEADLAMP's tools for environmental health management strives to- wards the prevention of environmentally related disease and the promotion of a healthy environ- ment. This is consistent with UNCED's Agenda 21 efforts for sustainable development as well as the ideals in the Alma-Ata declaration of "Health for All". Agenda 21 recognizes that both insufficient and inappropriate development can result in se- vere environmental health problems. Thus, while development cannot occur without a healthy population, such development should in tum not create additional environmental health problems ( 1). "Health for All" ideals of equity in health are also closely linked to environmentally related health problems, where it is clearly recognized that some sectors of the population are adversely affected by their living environment, and by poor access to health setvices. The implementation of HEADLAMP activities at the local level aim at providing a contribution to these two processes already in motion. If effective environmental health decision-making and actions can be sus- tained and multiplied in many local situations, they will have a significant impact at the national and global levels. Summary This article gives an overview of the HEADLAMP project and its background. The project aims at bringing valid and useful information on the local and national health impacts of environmental hazards to those responsible for environmental health protection. Its main tools are health and environment data linkage methods, environ- mental health indicators used to quantify arid monitor the local situation, and the interpretation and decision- making process. The project has 3 main characteristics which differenti- ate it from ad hoc epidemiological studies: (i) it is based on scientifically established relationships between envi- ronmental exposures and healtll effects; (ii) it uses routinely-collected data. or where necessary, new data collected using low-cost techniques; and (iii) it aims at providing information on which to base preventive ac- tion against environmental health problems. Based on these characteristics, a framework is proposed for the application of HEADLAMP for managing specific envi- ronmental health problems. Resume Analyse sante et environnBmenl pour Ia prise de decision Cet article presente le projet HEADLAMP (analyse sante et environnement pour Ia prise de decisions) et le contexte dans lequel il se place. Ce projet est destine a fournir aux responsables de !'hygiene de l'environne- ment des informations exactes et utiles sur les conse- quences sanitaires, aux niveaux local et national, des risques lies a l'environnement aux responsables de f'hygiene de l'environnement. II fait appal principale- Rapp. trimest. statist. sanit. mond., 48 (1995) ment aux m~thodes de raccordement des donn~~ sur Ia sante et sur l'environnement, aux indicateurs de Ia salubrite de I' environnement utilises pour quantifier et surveiller les probl~mes locaux, ainsl qu'au processus d'interpretat ion de prise de decisions. Le projet presente trois caracteristiques principales qui le differencient des etudes epidemiologiques ponctuef- les : i) il se fonde sur des relations scientifiquement averees entre des risques lies a l'environnement et des effets sur Ia sante; ii) il utilise des donnees recueillies de mani~re systematique, et, si necessaire, d 'autres don- nees rassemblees a !'aide de techniques peu coOteu- ses; iii) il fournit des informations qui serviront de base A Ia prevention des problemas de safubrite de l'environ- nement. Le schema etabli a partir de ces trois points pourra servir de cadre A !'application du projet pour gerer les problemas concrets de salubrite de l'environ- nemEmt. References/References 1. Agmda 21. 17u United Natitms Program'IM of Actilmfrom JUo. · Nc:W York, United Nations, 1993. 2. Our Ptmut ()u1' HltllJA. ~ oft!u WHO CommWion on Htaltli andEnvirotlmmt. Geneva, World Health Organization, 199!; 3. Be.pbole, R. etat &sic tpidntiolnf;f. 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