Environmental health surveillance: why and how?

Transcription

1 Minutes of the conference Environmental health surveillance: why and how? June 22 nd, 2009 Salle Pierre Laroque Ministère de la Santé et des Sports, Paris

2 Contents Preface 1 Environmental health surveillance: issues in debate? 2 The scope of environmental health surveillance 2 The means and the purpose of Environmental health surveillance 4 Opening address: Sophie Delaporte, Deputy Director General for Health 6 Session 1: What is environmental health surveillance? 7 1. Air and health monitoring programme 7 2. Monitoring childhood lead poisoning 9 3. Heat and health monitoring Environmental health surveillance: definition and concepts 12 Session 1 debate: What questions does environmental health surveillance enable us to answer? 15 Session 2: What obstacles need to be overcome to improve environmental health surveillance? Survey on the crossing of environmental health data Specific monitoring of a dermatitis epidemic caused by products contaminated with dimethylfumarate Biomonitoring: the National Nutrition and Health Study (ENNS) Discussion of the relevance of establishing health surveillance systems for basic nuclear facilities 26 Session 2 debate: What difficulties lie in the path of environmental health surveillance? What are its future prospects? 29 Closing address: Françoise Weber, Executive director of InVS 34 Abbreviations 35 Environmental health surveillance: why and how?

3 Preface page 1 The French Institute for Public Health Surveillance held on 22 nd June, 2009, at the Ministry of Health and Sports in Paris a conference on Environmental Health Surveillance. The conference aimed at outlining issues related to Environmental health surveillance: - its current scope; - the questions addressed by Environmental health surveillance and the ones it does not address; - the difficulties encountered by Environmental health surveillance and the means that could be used to overcome these difficulties. According to the organizers will, the conference was widely opened to exchanges between the audience and experts. In aimed at introducing these exchanges, oral communications focused on concrete examples of Environmental health surveillance. Feedback questionnaires filled by the participants indicate that these debates were valued, some participants even wishing them longer. This document is split into two parts: in the first part, the Scientific Committee of the Conference identified ten points that were still debated at the end of the day; the second part summarizes the minutes of the conference, reporting its main outcomes. The Scientific Committee of the Conference

4 page 2 Environmental health surveillance: issues in debate? The scope of environmental health surveillance Exchanges hold during the conference addressed questions faced by Environmental health surveillance today. They demonstrated that its scope was still debated. In the future, this debate could be enriched by the diversity of stakeholders (civil society, policy makers, health professionals, public health specialists). The scope of Environmental health surveillance is logically deduced from the Environmental Health s one: "Environmental health comprises those aspects of human health, including quality of life, which are determined by physical, chemical, biological, social, psychosocial and aesthetic environment. It also covers policy and management practices, resorption, control and prevention of environmental factors may affect the health of present and future" (defined by the European Office of World Health in Conference Helsinki 1994). Human diseases are mostly multifactorial. They arise because of exposure to numerous environmental modifying or determinants factors, behavioral factors and hereditary factors (called as susceptibility factors). Thus, in the framework of environmental health surveillance, "monitored entity" or "entity which should be monitored" is not univocal. It can be environmental risk factors, diseases related to environment, or identification of potential health risks based on reported cases or environmental exposures whose toxicity is suspected or confirmed. Boundaries between surveillance and other disciplines of environmental health such as observation, watching, research, investigation, screening, vigilance and monitoring are therefore difficult to define. What should we monitor? Identifying issues that Environmental heath surveillance cannot address could partially answer this question. For example, environmental health surveillance does not allow estimating, at an individual level, a specific risk due to an environmental exposure. This is the concern of medical (or forensic) enquiries. Moreover, it does not allow demonstrating a causal link between an environmental exposure and a disease, this being the field of etiological research. In front of environmental issues, we can legitimately wonder if surveillance can provide relevant answers. This step also allows identifying means needed to ensure that surveillance will reach its goals. The following issues were identified during the conference: Environmental health surveillance: why and how?

5 page 3 1) Should environmental health surveillance enable to estimate a health impact? Yes, such as the estimated number of deaths or hospitalizations due to extreme heat waves or exposure to air pollution, the number of cases of poisoning from carbon monoxide, health outcomes of post-accidental situations, etc. However, to be efficient, Environmental health surveillance requires access to existing databases (nation wide networks, routinely used information systems ). Having enough knowledge to assess the potential health effects of exposure, which could be particularly difficult when it comes to low dose of exposure or to emerging factors, is another pre-requisite. An accurate assessment of exposure is also necessary (e.g., exposure of the general population to natural ultra-violet radiation). 2) Could monitoring of environmental exposures (expology) be sufficient for Environmental health surveillance? Yes: when exposure-risk relationships are established, monitoring environmental exposures can be sufficient for Environmental health surveillance. This applies for example to the surveillance of acute effects (deaths) related to heat waves, which is based on meteorological data (daytime and night-time temperatures). However, it is clear that data on the causal relationships between environmental exposures and health effects are still scarce, and most remain research concerns. Moreover, numerous environmental exposures are characterized in the general population by low doses of exposure or exposures to emerging factors. In consequence, delimitating the scope of environmental health surveillance remains a hard task. 3) Could monitoring of exposure-risk associations be a goal for Environmental health surveillance? Yes, whilst some exposure-risk associations are well known, one goal of surveillance could be pursuing monitoring risks linking environmental factors and health. These associations can indeed change across time and locations, consecutively to human interventions: increasing, reducing or changing exposures, screening, prevention campaigns, etc. 4) Should Environmental health surveillance focus on vulnerable populations? Yes; for example children are particularly sensitive to environmental exposures and thus environmental health surveillance should systematically focus on such sub-populations (e.g., surveillance of childhood lead poisoning, or characterization of biomarkers in the ELFE cohort French Longitudinal Study since childhood). Since levels of environmental exposure and/or associated health risks are mostly still unknown in these populations, health surveillance can accordingly be necessary. Biomonitoring, which aims at measuring levels of biological impregnation of the general population or target populations, is a specific tool of surveillance. However, when the interpretation of the results of these measures is only partially known, such monitoring remains once again strongly correlated to research issues.

6 page 4 5) Should Environmental health surveillance enable to detect emerging factors? Yes monitoring is not only about what we know, but also about what is suspected to be responsible for adverse events throughout time. Once again this prospect is strongly linked with further advances coming from research. We are therefore in a position to ask whether monitoring issues on the one hand, and research issues on the other hand, can be performed separately with relevance. The methods and means used by these two disciplines are sometimes close. Hence, one can wonder whether both fields could benefit from mutualisation of human resources, methodological developments, databases developments, and financial costs and supports. This strong relationship is also not specific to environmental health and is relevant in the field of surveillance of infectious diseases too, for example. Strong links between research and surveillance would also help the whole decision process. 6) Finally, concerning its scope, should Environmental health surveillance monitor other health indicators than those of morbidity and mortality? Yes, because of uncertainties in the relationship between environmental exposures and risks of adverse health effects, indicators of mortality and morbidity are no longer sufficient to respond to growing public concerns. For example, perceived of quality of life, and its monitoring through polls, have an increasing impact on public authorities decisions. The means and the purpose of Environmental health surveillance Conjointly with the definition of the scope of Environmental health surveillance, means ensuring an adequate surveillance are also a concern. We present below some examples discussed during the conference: 7) Are there specific data for Environmental health surveillance? Administrative or medico-economic databases and information systems were usually set up for purposes other than environmental health monitoring. However, surveillance is largely based on these databases, although most are unspecific. The conference highlighted that there was currently a strong need for both individual and accurate georeferenced data (the town being the minimal information needed). Efforts should focus on establishing systems dedicated to Environmental heath surveillance, conceived and built before a specific issue arises. Despite its expensive cost, a full nation-wide diseases registry, integrating individual and geolocated environmental exposure information would be the key answer to environmental issues. This has recently been set up for records of solid tumors and hematologic malignancies of children (GEOCAP study). Environmental health surveillance: why and how?

7 page 5 8) Are all the tools necessary for Environmental health surveillance available? Whereas these questions were not discussed during the conference, the need for development of new monitoring tools, such as indicators for intervention effects, economic valuation tools like cost-effectiveness, as well as tools of appraisal, are parts of the forthcoming improvements of surveillance. 9) Does Environmental health surveillance take into account the mandatory need to protect personal data? Epidemiological surveillance is currently limited by a lack of records or possible link between individual data. Thus, the establishment and access to a common identifier would be a major breakthrough for every field of public health. Considering it as an ethical issue, the audience and the experts Committee of the Conference stated that the possibility to create or access personal data needs to be explicitly and widely debated by policymakers and society. 10) Does Environmental health surveillance facilitate decision making? Surveillance leads to decision making and societal actions that often go beyond health actions strictly, and involves other financial resources and political or social interest. Therefore, surveillance has to anticipate management measures resulting from its findings and recommendations (e.g. in the field of inadequate housing). Environmental health surveillance remains an imperfect tool for decision support, especially for emerging factors for which causal relationships or dose-response curves are still the objects of researches (bisphenol A, base stations, mobile phones, nanoparticles, etc). As a conclusion, since transparency in every decision taken by public authorities is a requirement of democracy, the whole society has to be informed of the potential or proven risks and their possible alternatives, to guide its own choices.

8 page 6 Opening address: Sophie Delaporte, Deputy Director General for Health I am delighted to welcome you to this conference, organised by the Institut de veille sanitaire. We will be looking at three issues, namely the scope, purpose and limits of environmental health surveillance. I will begin with the example of heat waves. In this case, surveillance activities focus on one determining factor, the temperature. Depending on how high it rises, the InVS and Météo-France may alert the authorities. Environmental health surveillance covers two aspects: environmental determinants and environment-related pathologies. It facilitates decision-making by the public authorities. Toxicant monitoring, for example, enables us to identify risks on the basis of reported events. It also helps us to manage cases of poisoning more effectively, by identifying the substances responsible and hence the most appropriate treatment. Environmental health surveillance also enhances our knowledge of environment-related pathologies. A number of procedures have been introduced, for example the compulsory reporting of cases of lead poisoning and of legionnaires disease. However, these procedures have a limited area, given that most environment-related pathologies are multi-factorial. One of the main questions surrounding environmental surveillance is how do we take society s expectations into account? Opinion polls confirm that there is a growing public desire for more information on potential risks, or on factors that are perceived as impacting quality of life (although, in some cases, no health effect has been demonstrated). If it is to improve our understanding and answer the questions raised, environmental health surveillance must maintain close ties with research and with the social and human sciences. We will also be talking about biomonitoring during the conference. The main purpose of biomonitoring is to measure pollution absorption in the general population, monitor spatial and temporal trends in exposure, analyse the effectiveness of exposure reduction strategies and alert the authorities in the event of danger. France could use existing programmes in other European countries as a basis for developing its own. Cohorts are a particularly suitable means of studying the long-term effects of environmental factors. The French Longitudinal Study of Children, called as ELFE study, will monitor 20,000 children from birth, and will analyse the development of each child in his/her environment and the interaction of different factors right through to adulthood. Before implementing a system for systematically monitoring health data, we must determine how appropriate it is in terms of the scale of the data collection management system, the diversity in the information sources used and the funding available. Environmental health surveillance is a fully-fledged discipline in itself. It produces results but cannot answer all the questions regarding the impact of the environment on health. I would like to thank InVS for organising this conference, and to wish you the greatest success in your work. Thank you for coming. Environmental health surveillance: why and how?

9 Session 1: What is environmental health surveillance? page 7 1. Air and health monitoring programme Christophe Declercq, InVS, Department of Environmental Health The great London smog of 1952 killed several thousand people, and regulations were introduced in its aftermath to reduce pollution. Since the early 1990s, modern statistical methods of analysing time series have shown that pollutants such as airborne particles and ozone have a significant effect on mortality at present levels of exposure. This conclusion was confirmed by the ERPURS programme, which used data provided by the Ile-de-France air quality monitoring network to analyse the health effects of urban pollution. This programme was also instrumental in the introduction of the Air Pollution Law on 30 th December 1996, which stipulates that the government is responsible for monitoring air quality and its effects on health and the environment. In 1997, the Réseau national de santé publique (RNSP National Public Health Network) set up an air and health monitoring programme. The purpose of this programme was to assess the health hazards associated with exposure to ambient air pollution, monitor trends in the occurrence of these hazards and evaluate the air pollution health impact in French cities. One way of monitoring health effects might be to monitor health events. However, although exposure to airborne particles can aggravate symptoms in asthmatics for example, other risk factors can also be involved. So monitoring a specific health indicator does not work. An alternative approach might be to monitor determinants. Given the complexity of the indicators, the environmental health surveillance system must monitor exposure, health effects and the relative risks, based on a network of partners. The results are moreover communicated to all the different stakeholders. The Programme de surveillance air et santé (PSAS Air and Health Monitoring Programme) is based on a network such as this, coordinated by the InVS and composed of local and national partners. Using the data collected, the goal is to develop a set of daily health indicators aggregated to the scale of an agglomeration and a set of average exposure indicators for the same area, and then to analyse the relationships between these two time series. This means that relevant confounders must be taken into account. A separate analysis is conducted per city, and then a joint analysis is carried out to estimate the relative risk for all the cities together. In particular for airborne particles and ozone, recent results show that the current short-term variations pollution levels do carry a health risk (especially a risk of mortality and hospitalisations for cardiovascular diseases). There is a clear and continuous link between levels of exposure and levels of health effects, without any threshold in the general population. This observation suggests that the authorities should not be focusing only on managing pollution peaks but act to reduce emissions of pollutants. Other studies, carried out in the framework of PSAS, have shown that ozone contributed to the excess mortality rate during the 2003 heat wave.

10 page 8 The monitoring programme will be pursued in the future, given the upward trend in air pollution, and the related health impact, but also the development and use of other health and air quality indicators and the extension of monitoring to include the long-term effects of chronic exposure to air pollution. A partnership has been developed for this purpose with the INSERM (National Institute for Health and Medical Research) and the AASQA (National Air Quality Monitoring Network). Questions Daniel Eilstein, InVS The PSAS operates in nine cities. Can you explain this decision? Christophe Declercq Our initial goal was to roll out the programme in a reasonable number of cities, taking account of available funds and diversity requirements. We also tried to identify local partners willing to take part in the initiative. When I said that the monitoring programme will be pursued in the future, I was referring to initiatives throughout France. However, the programme has to be adapted to the specific features of individual regions: we needed quite large cities with different climate, socio-demographic and health characteristics in order to make sure that our studies would be statistically significant. Sylvaine Cordier, INSERM How do you intend to assess long-term effects? Christophe Declercq We were not in favour of the idea of setting up a cohort project. Instead, we have entered into a partnership with a team at the INSERM, working with the GAZEL cohort. We are working with the AASQA to characterise the cohort s exposure. Jean-Claude Desenclos, InVS How does this programme illustrate the specific concept of environmental health surveillance? Christophe Declercq Environmental health surveillance cannot be based exclusively on either health effect or exposure indicators. We must take both aspects into consideration. With regard to cooperation between surveillance and research, partnerships with research teams seem crucial, particularly for the characterisation of long-term airborne pollution effects. Environmental health surveillance: why and how?

11 page 9 2. Monitoring childhood lead poisoning Philippe Bretin, InVS, Department of Environmental Health Lead poisoning monitoring focuses on children, who are more vulnerable than adults due to their hand-mouth activity, their high digestive absorption rate of lead and their sensitivity to the effects of lead. Such monitoring enables us to determine whether prevention measures are implemented correctly and effectively. There are several sources of lead exposure for children: lead paint, industry, kitchen utensils, khol, tap water, contaminated sites and soils, etc. The main route of exposure for children is ingestion, followed by inhalation. A biomarker (the blood-lead level) is used to assess overall lead exposure. Monitoring the effects of lead exposure is tricky. In children, the nervous system is affected, leading to learning difficulties, reduced mental capacity, etc. Thus, cases of lead poisoning correspond to a blood-lead level above 100 micrograms per litre. Exposure monitoring targets the entire population. It consists of repeated cross-sectional studies (prevalence surveys), which aim to track the spatiotemporal progress of lead absorption in children and trends in the determinants of this absorption, and to identify populations most at risk. In addition, France has set up the "Système national de surveillance des plombémies chez l enfant" (SNSPE - National System for Monitoring Blood-lead Levels in Children). The SNSPE is a continuous monitoring system, the purpose of which is to evaluate screening activities and measures to protect children at risk of exposure to lead. The prevalence survey conducted by the INSERM and the RNSP from 1995 to 1996 were repeated in The results of the initial surveys ( ) highlighted the risks associated with old buildings and poor water quality. The results of the new survey will be available in The SNSPE keeps a record of all the blood-lead tests prescribed by doctors. The laboratory sends the results to the doctor and to the poison control centre, which in turn sends the information to InVS. The DDASS (District Directorate for Health and Social Affairs) is also informed of cases of lead poisoning, so that it can identify the source and take the necessary measures. The DDASS transmits the information on these cases to InVS so it can verify the completeness of its database. The above two monitoring systems are very different in terms of the way they operate and their objectives. Prevalence studies provide identification and following data on lead absorption and on the determinants of this absorption, whereas the monitoring of screening activities allow evaluating how doctors follow according recommendations and what are the results of these screening activities in terms of number of identified cases. Only prevalence surveys allow assessing the impact of primary prevention measures.

12 page 10 Questions From the floor Are you planning to target screening operations based on your knowledge of the state of housing in certain neighbourhoods? Philippe Bretin The screening system targets both populations and individuals. Screening has always begun in at-risk neighbourhoods. One of the main purposes of the prevalence survey is to provide information on how to target screening operations according to housing-related factors. Therefore, we will explore the relationships between the characteristics of the survey area in which child included in the study live and their related blood-levels. 3. Heat and health monitoring Karine Laaidi, InVS, Department of Environmental Health This monitoring system was set up by InVS and Météo-France after the 2003 heat wave. Various studies have been conducted to determine risk factors in the elderly in particular. The monitoring and warning system, which is part of the heat wave action plan, operates on three levels: a first one of seasonal temperature watch, from June to August, a second one of warning followed by action if a heat wave is forecast or happening, and a third one of highest mobilisation of the network in case of an intense heat wave. The purpose of this system is to prevent an epidemic of deaths arising from a heat wave. The meteorological indicator used is the average minimum and maximum temperature over three days. Different alert thresholds have been defined according to the département 1. Other meteorological factors, such as the reliability of weather forecasts, are also taken into consideration, as are aggravating factors like the intensity and length of the heat wave and relative humidity. Based on these criteria, Météo-France may issue a weather warning. We also monitor health indicators to determine the impact of the heat wave. We monitor non-specific data in real time, i.e. the overall mortality rate and non-specific morbidity. These data are analysed by the "Cellules interrégionales d épidémiologie" (CIRE Interregional epidemiology units). In addition, the OSCOUR network (Organisation of Coordinated Surveillance of Emergency Departments) and SOS Médecins (GP s emergency associations) monitor national pathology-specific data, which are analysed by InVS. The analysis of the meteorological data involves defining the probability of abnormally high temperatures; expert input is also provided by Météo-France. This analysis can lead to propose an alert to public authorities. A state of alert may be maintained in view of the health indicators. 1 French administrative region. Environmental health surveillance: why and how?

13 page 11 In alert, the information gathered by the CIRE and Météo-France is sent to the Directorate General of Health, which issues the alert report and guidelines of management to national and regional partners, in particular to the prefects who are responsible for the implementation of the plan at the local level. The purpose of the monitoring procedure is to notify the health authorities and prefects of the risk, on the basis of expert information from Météo-France and InVS. The prefect may implement a number of measures to manage the situation: assistance for elderly people living alone, installation of a freephone number, etc. Hence the public is informed of the risk of a heat wave and how to protect themselves through radio media, TV, leaflets and web sites The national press may be called upon to promote appropriate behaviour and solidarity. Thus the monitoring system prevents excess deaths due to high temperatures, and also serves to notify the health authorities of the risk. Since the system was set up in 2004, two heat waves have occurred. The biggest one affected 68 départements in 2006 and caused 2,000 excess deaths. A prediction model had forecast 6,000 deaths, assuming that awareness of the risk was low, and that there was no monitoring and warning system, and no action plan. Although the effective number of deceased people was lower than the expected one, it has not been possible to estimate the impact of the monitoring system on these outcomes. Questions Sylvaine Cordier, INSERM Have you noticed a connection between the temperature and air quality, especially in urban areas? Karine Laaidi Research has shown that temperature has a greater health impact than air pollution. Christophe Declercq A heat wave is an isolated event, with particularly high temperatures and ozone levels. We have studied the role of ozone. It is difficult for us to draw any conclusions on the basis of such a short episode, but we are trying to do it over time. Daniel Eilstein Christophe, the PSAS monitors exposure and health effects, and the way they interact. Why not just monitor exposure and issue warnings accordingly? We know that the heat-health monitoring programme allows prefects to put their département in a state of alert. Do we have any feedback on the conformity of prefectoral decisions with InVS guidelines?

14 page 12 Karine Laaidi In 2008, a specific application was introduced enabling prefects to inform us of their decision to declare a state of alert. However, we haven t had a heat wave since then. Studies conducted over the last two years have shown that InVS guidelines are being followed on the whole. Blaise Koudogbo, Pan-African Association for Human and Nature Protection Did the 2006 heat wave arise from a change in temperature or from the air quality? Karine Laaidi We didn t monitor the air quality very closely. We observed a clear increase in the mortality rate due to the high temperatures. However, the ozone level may have been an aggravating factor. Mario Demicheli, DRASS Poitou-Charentes Temperature is a very independent variable. The rise in temperature probably made people more vulnerable. Christophe Declercq We saw a big difference between cities. The impact of the high concentration of ozone was greater in cities like Marseille and Lille where excess mortality was lower. The high temperatures definitely had the most impact in Environmental health surveillance: definition and concepts Daniel Eilstein, InVS, Department of Environmental Health "Surveillance can refer to the act of monitoring itself, and to the control measures arising from it. It implies that the observing party is keeping watch and that the party under observation is visible 2." Environmental health surveillance essentially means public health surveillance, as it matches the definition of epidemiological surveillance 3. However, it also involves an environmental watch, which leads to the current widely-accepted definition of this concept. 2 Encyclopédie philosophique universelle. Les Notions philosophiques. Dictionnaire 2. PUF, 1 re éd Stephen B Thacker, en 1996 (Thacker SB. Surveillance. In: MB Gregg, eds. Field Epidemiology. New York: Oxford University Press, 1996:16-32.) définit la surveillance épidémiologique (ou de santé publique) de la façon suivante (traduction): "Public health surveillance (sometimes called epidemiologic surveillance) is the ongoing and systematic collection, analysis, and interpretation of outcome-specific data essential to the planning, implementation, and evaluation of public health practice closely integrated with the timely dissemination of these data to those who need to know. The final link of the surveillance chain is the application of these data to the control and prevention of human disease and injury." Environmental health surveillance: why and how?

15 page 13 The environment is not necessarily harmful (vitamins, antioxidants, stratospheric ozone, lactobacillus). It is not always influenced by human activity (sunshine, radon) or necessarily endured by humankind (active smoking, alcoholism). The interactions between the environment and an individual s inner state are continually changing throughout that individual s life. The environment is made up of living environment, vectors, populations and agents. The living environments contain the vectors, agents and populations. The vectors are entities that bring the environmental agents into contact with the populations. The agents are directly responsible for the effects observed. There are several types of agents: potentially pathogenic biological agents, physical and chemical agents that have nothing to do with human activity, and potentially harmful physical, chemical and biological agents that derive from human activity. The social context is hard to categorise, as it is multi-faceted. Environmental health surveillance focuses on the health risks arising from specific living environments or agents, diseases that are potentially related to the environment, populations that are particularly sensitive and the interaction between all these elements. It consists of a set of monitoring systems, which are established on the basis of specific reports and existing data. However, it can also operate alongside cross-sectional studies or longitudinal monitoring programmes. The monitoring process consists of a design phase, during which the indicators are defined and the necessary raw data are identified. These data are put together and used to define the indicators. They are then descriptively analysed and modelled statistically, and the results are used to assess the health impact or draw up different scenarios. The conclusions are then communicated to the general public, decision-makers and health professionals. In the future, we would like environmental health surveillance to include action indicators, with a view to monitoring the relationship between these indicators and environmental, health and population indicators. We also hope to see economic tools such as cost-effectiveness ratios integrated into environmental health surveillance to facilitate the decision-making process. The introduction of integrated surveillance systems would enable us to monitor exposure to groups of pollutants. We are also investigating the scope of surveillance compared to that of observation, watch, research, investigation, screening, control and follow-up operations. For example, research aims essentially to define causal links, whereas surveillance seeks to establish exposure-risk functions. Questions Jean-Claude Desenclos You said that you hope to see economic tools integrated into environmental health surveillance. In view of the tools that still remain to be developed, is "integrate" really the appropriate term?

16 page 14 Daniel, you also stated that it is not necessary to know the causal links to issue an alert. Can an alert really be issued without understanding the causal links? Isn t it a bit presumptuous to evaluate the surveillance system? Daniel Eilstein "Contributing" to the evaluation process is a better way of putting it. The surveillance process provides evaluation tools. When I talked about causality and exposure-risk functions, I was referring to situations in which the environmental and health indicators vary concomitantly (in a correlated manner). In these situations, the relationship does not need to be causal to trigger an alert (for example, an ozone alert). This raises the issue of the principle of caution, which we need to be very wary of if misinterpreted. When I talked about integrating economic indicators, I meant that it is important to use a cost-effectiveness ratio and that the economic indicators should be monitored like the others. In fact, we now know that mortality and hospitalisation indicators are no longer adequate to accurately determine the impact of the environment on health. Georges Salines, InVS The conceptual model on which InVS has based its activities for many years includes both environmental and health indicators, and takes into account the relationship between the two. It is important that we know the status of the indicators that we are monitoring, even if we are focusing on just one aspect depending on our goals and what we know about the different relationships. For example, with regard to the national heat and health alert system, let s suppose that we have approached Météo-France only, for the purpose of obtaining meteorological indicators. This would still be environmental health surveillance with a view to issuing an alert, as we have already established alert thresholds for heat-related excess mortality. Daniel Eilstein When there is a causal link or a correlation between environmental exposure and health surveillance, we only need to monitor one of the two indicators (exposure for example). However, the PSAS claims to monitor environment and health-related risks, as these can change. And we generally have to act quickly, so we can t spend too much time analysing a lot of indicators. Environmental health surveillance: why and how?

17 Session 1 debate: What questions does environmental health surveillance enable us to answer? page 15 Debate with the floor Pascal Chaud, coordinator of the CIRE North, InVS Isabelle Gremy, head of the Île-de-France Regional Public Health Observatory (ORS) Joëlle Le Moal, epidemiologist, Department of Environmental Health, Toxicity Control and Biomonitoring Unit, InVS Jean Lesne, French Agency for Environmental and Occupational Health Safety (AFSSET), head of the Methodology, Research and External Relations Department Didier Torny, sociologist, research fellow at the French National Institute for Agricultural Research; Risks, work, markets and state s unit And the participants in the first session The debate was led by Jean-Claude Desenclos, scientific director at InVS. A participating occupational doctor My question is for Christophe Declercq. You talked about biological exposure and effect indicators. Did you deliberately not mention biological predisposition indicators? Christophe Declercq It is true that pollutants do not have exactly the same effect on everyone. But the indicators we use apply to the entire population. Epidemiological monitoring does not, on principle, apply to individual people so predisposition indicators are irrelevant. Nevertheless, it would perhaps be worthwhile to encourage screening for people with significant vulnerability factors. Jean-Claude Desenclos Pascal, can you tell us what questions environmental health surveillance enables us to answer in the north of France, particularly those relating to carbon monoxide poisoning? Pascal Chaud We have seen several outbreaks of carbon monoxide poisoning in the last few years, associated with weather conditions that prevented the evacuation of combustion gases. The causes have now been identified: a reduction in the draught of heating systems and less efficient evacuation of combustion gases. We are trying to identify criteria that will enable us to predict or detect these situations before they arise. Météo-France, who were sceptical at first, agreed to work on national surveillance data and have managed to establish a correlation between epidemic periods and spells of atmospheric stability, milder weather and high humidity rates. Thanks to this preventive action, we are able to issue warnings in advance about the dangers of using coal heating systems. The wide circulation of this information via the press is very encouraging.

18 page 16 Jean-Claude Desenclos What do sociologists think about this? Didier Torny We know that all new systems are introduced after a crisis and in response to strong political demand. However, the long-term benefits of these systems are brought into question as soon as the initial interest dies down. Even in the short term, requests can only be fulfilled if there is a long-term action plan. To judge the significance of a cluster, it is necessary to define thresholds: a standard based on historic, geographic and compared measurements. The main question lies in the relationship between short-term action plans which provide precise answers and long-term action plans requiring costly structures. In fact, the best strategy is to combine actions that are potentially financially profitable and scientifically advantageous in the short term with long-term knowledge-building measures. With regard to lead, the government has issued a decree obliging property owners to update their plumbing and paintwork where necessary. We are therefore moving away from surveillance and screening towards political action, which often goes beyond health measures and involves greater financial resources and wider political and social interests. Jean Lesne The terms "environmental health" and "occupational health" are derivatives of "public hygiene" and "occupational hygiene" in the workplace. In the last ten years, we have progressed from a situation in which the risks were clearly identified and preventive measures provided significant improvements in terms of health, to a much more dispersed system with many sources of exposure leading to long-term, slight and non-cumulative health effects. It is vital that we perform a reliable, full-scale study of biological effects in the population, and that we cross the resulting data with those obtained through environmental surveillance. Sanitary control still exists, but it needs to be directed towards these new risks. Jean-Claude Desenclos Jean, could you give us a few examples of your experience? Jean Lesne Conventional public hygiene measures are based on faecal contamination indicators. AFSSET and InVS have conducted a research project in which they crossed morbidity indicators (cases of acute gastro-enteritis) with faecal contamination indicators for the same environment. The results were very interesting in terms of justifying the need for environment quality standards for health reasons. Environmental health surveillance: why and how?

19 page 17 Jean-Claude Desenclos Isabelle, have the surveillance procedures at the ORS been useful in answering any of the questions raised, or helped to progress public health and prevention? Isabelle Gremy I think that they have improved our knowledge more than public health or health prevention. As head of the Ile-de-France ORS, it is my job to know everything there is to know about public health in the Paris area. The relationship between health and the environment is the most difficult aspect to manage. Our institute, which employs 17 people, covers the full-span of health-related issues, including chronic diseases and key health trends. The CIRE are in charge of issuing health warnings. Environmental pollution problems are particularly bad in Ile-de-France, which is a densely-populated region; therefore the ERPURS programme was set up in the 90s, and we were and still are closely involved in it. The Regional Council often asks me questions about currently-crucial issues, such as exposure to incinerators, aerial relays, etc. The local authorities do not seem able to answer such questions, even the most fundamental ones like how to define waves, how do they affect quality of life, etc. They ask us to assess the local impact of their transport, housing or town planning policies, bearing in mind the interdependence between social and environmental policy issues. Jean-Claude Desenclos Could it be said that surveillance systems provide answers to the type of questions that Isabelle has just mentioned? Joëlle Le Moal The most difficult questions arise when the effects of environmental exposure are only suspected or even unknown. I myself deal with chronic and so-called complex, multifactor diseases. In the case of the Franklin Roosevelt school, which was polluted by the former Kodak factory, we were unable to determine at the time whether there was an excessively high rate of cancer among the children there. We have had to put together a post-factum tumour registry. Without surveillance data, we cannot establish whether the cancer rate was too high or not. Adult cancer registries only cover 18% of the French population. Only childhood cancer surveillance systems cover the whole country: the national registry of childhood leukaemia and lymphoma (since 1990) and the national registry of childhood solid tumours (since 2000). We are currently working on the GEOCAP project with INSERM Unit 754, which is run by Jacqueline Clavel. This project aims to geocode all childhood cancers. As pointed out in a German publication that records cases of childhood leukaemia, it will provide answers on how dangerous high-voltage power lines are for example, or the effects of a nuclear power plant on the local environment. Thanks to GEOCAP, we will be able to cross data and answer these questions, on the basis of 15,000 control cases of childhood cancer. Ultimately, we hope to be able to identify clusters before they appear. In the same way, biomonitoring provides a highly valuable means of studying the relationship between health and environment.

20 page 18 Carole Grandemange, Public health inspector I still don t really know what environmental health surveillance is. The speakers this morning all provided different explanations depending on their professional background. But I do see the overall benefits. From a field management perspective, can environmental health surveillance be an alternative to the abusive use of the principle of caution? Didier Torny The abusive use of the principle of caution is a combination of politics and expertise and is, by definition, out of proportion. When a problem is identified, we are not necessarily in a position to solve it. Here lies the main conflict between knowledge and resources. Politicians would like to be able to reverse situations and generate the knowledge needed to avert disasters as soon as possible. Georges Salines The best way to solve a problem of definition is to proceed by elimination and to classify questions to see whether they fall within the scope of environmental health surveillance or not. So, this is my question: "What questions does environmental health surveillance not provide an answer to?" Isabelle Gremy The Regional Council has asked me if there is a link between sunscreen creams containing nanoparticles and health effects. This is a question for researchers, not the ORS. It is methodologically complicated especially in regard to causality as the risk is too low and several other factors are involved. However, this sort of response is not usually very well received. We must pay closer attention to the public s expectations and perceptions. Michel Jouan Could environmental health surveillance systems be used to regulate social demands, which must be channelled for financial reasons? Jean Lesne We are ignoring the economic aspect, despite the fact that it is essential. The principle of "who pollutes, pays" is just as valid as the principle of precaution. Environmental health surveillance should help us to measure the health impact of management policies. We have to handle situations without knowing why they have arisen, which falls more within the scope of pure research. Environmental health surveillance: why and how?

21 page 19 Jean-Claude Desenclos Assessing the impact also falls within the scope of research. From the floor How much is the GEOCAP project costing? Who will have to pay for monitoring cancer occurrence over the long term? Joëlle Le Moal The cost of the GEOCAP project has been established. The Health and Environment Department is covering part of it. A national, multi-source cancer monitoring system is being set up. It will cost a lot of money, but not as much as establishing a post-factum registry. Emilie De Marco, lawyer From a legal point of view, the principle of caution encourages decision-makers to take all the risk factors into consideration and to prohibit certain activities if the risk is too high. In this context, environmental health surveillance facilitates decision-making in the public health arena. Daniel Eilstein It was important to discuss the scope of action of environmental health surveillance. Some situations fall more within the scope of research or clinical supervision (i.e. the medical supervision that doctors exercise over their patients). The Health and Environment Department regularly attempts to answer this kind of question.

22 page 20 Session 2: What obstacles need to be overcome to improve environmental health surveillance? 1. Survey on the crossing of environmental health data Jérôme Lozach, AFSSET, Methodology, Research and External Relations Department This survey, coordinated by AFSSET, the Institut français de l environnement (French Environment Institute) and a pluri-institutional group, was conducted under the frame of action 35 of the PNSE (National Health and Environment Action Plan). Its purpose was to assess the feasibility of crossing data from environmental, health, populational and/or demographic databases. Mostly on the basis of the draft calls for research proposals, we brought in scientific teams and then defined study selection criteria: the studies had to be based in France, involve data crossing and use at least one existing database. The interviews were conducted in accordance with standard interview guidelines. The studies examined focused essentially on epidemiological analyses, health events and environmental risk factors. The data sources were extremely diverse (satellite pictures, databases, questionnaires, etc.). We discovered that identifying the content of the data sources and establishing their usability was a time-consuming and repetitive task. The data had often been obtained through personal connections and negotiation, before being subject to specific legal requirements and conditions. With a few exceptions, these data were either inexpensive or their price was attractive. The scientific teams analysed available data to ensure they were compliant with the study s objectives, allowing early identification of potential bias or uncertainties. This matching was performed by selecting already existing data, although imperfect, going back to the local data sources and their providers, or formulating new working hypotheses. The pre-processing of the data, which consisted in extracting reliable and usable data, showed that the data manager is an indisputable service provider (selection of relevant data). Furthermore, cleaning the database corrects erroneous data and deletes any unnecessary information. If there are no data available, or if they are not appropriate, new data are generated through expert appraisals, questionnaires and modelling tools. A focus on the estimation of exposure to environmental factors showed that exposure data are rare, and that any data of this type are fragmented in time and space. Moreover, aggregated data are not necessarily representative of individual exposure. Environmental health surveillance: why and how?