Faculty of Medicine
Department of Epidemiology and
Statement of the project's scientific bases and aims
The RIF development process
Phase III Protocol
Statement of the project's scientific bases and aims
The aims of the EUROHEIS project are to improve health information and analysis in order to assess relationships between environmental pollution and disease, and to respond rapidly to health threats, improving knowledge and understanding of health risk management. We have developed and implemented a Rapid Inquiry Facility (RIF) to explore the links between exposure to environmental pollutants and possible health risks.
The objective for the third year of the project is to demonstrate the usefulness of the RIF in answering questions concerning environmental health risks, utilising the system within the context of improving public health, preventing human illness and diseases, and obviating sources of danger to health. We will demonstrate this through a series of case studies carried out within each of the partner countries. The impact of socio-economic factors will be incorporated in the analyses, and the use of the systems for environmental health impact assessment will be assessed in collaboration with another project (APHEIS) funded within the programme for "Action on pollution related diseases".
EC contract number: SI2.132454 (99CVF2-606)
Feasibility study: 15/12/1999 to 14/12/2000
EC contract number: SI2.291820 (2000CVG2-605)
Implementation phase: 15/12/2000 to 15/05/2002
EC contract number: SI2.329122 (2001CVG2-604)
Evaluation phase: 16/05/2002 to 16/05/2003
The RIF development process
A one-year feasibility study was undertaken in the first year of the project to assess the possibility of implementing a system for point source investigations and disease and hazard analysis within participating countries, modelled on a system being developed within the UK. The feasibility study also aimed at developing the UK system to include more generalised modules for disease and hazard analysis, to explore techniques for taking into account inconsistencies in the data, and to assess the availability of indices of socio-economic status derived from routinely collected data sources. All development was done in harmony with EU partners.
An initial version of the RIF was developed and this provided a basic framework for the present version, whose functionality has been enhanced and expanded through the development of a series of modules to enable small area disease mapping and enhanced point source analysis. The modules are complementary and were identified as a result of discussions with partners in the EUROHEIS project and discussions in-house within SAHSU. The modules provide the mechanisms by which values can easily be added to the RIF; for example when new health datasets are acquired, when new geographies are needed, or when new different methods of defining the study area are appropriate. The concept and methodologies inherent in the modules can be generalised and, because they are written using proprietary software, they are thus transferable to the other partner countries in EUROHEIS.
The present RIF system
The present RIF system has been developed using ESRI Arc View 3.2a GIS and Oracle 8i. The development phase entailed the interpretation of the theoretical aims of the project into a rapid, practical, user-friendly and powerful generic tool into which partners could easily 'plug-in' their datasets. The aim was to create a simple system with one GIS front end linked directly to the database that could be easily implemented by partner countries using different spatially referenced datasets. The system had to be intuitive in order that non-computational users could easily and rapidly run investigations, for example assisting epidemiologists in policy-making and routine disease-mapping.
The RIF implementation
The successful implementation of a system for hazard analysis and disease mapping is greatly dependent on suitable data being available for use within the systems. Not only must the required datasets be available, they must also be of sufficient quality to enable meaningful and interpretable analyses. In some countries the potential for very detailed small area studies is good; in others there are dataset issues to be solved, which pertain mainly to the size of the geographical base units and to the sparseness of the data. In these cases the potential of statistical methodologies, at least partially to overcome such problems, has been explored as part of the feasibility study. In general, a Bayesian hierarchical modelling approach is recommended for statistical analysis of disease/hazard analysis studies and point source investigations. These methods allow raw disease rates to be 'smoothed' to overcome problems of sparse data and provide a natural framework for incorporating common features of the data such as over-dispersion, spatial correlation, missing data, exposure measurement error and ecological bias.
The RIF is presently being applied to the exploration of health impact assessments using exposure and disease mapping modules. For example the 'hazard analysis' module can be used to define populations that are exposed to different pollution levels, to evaluate existing exposure response data and to examine health impacts of defined environmental exposures. The 'disease mapping' module allows users to monitor health outcomes that may potentially be related to sources of environmental exposure. The system also gives an insight into social inequalities in health, providing structurally equivalent 'deprivation' scores and calibrating modelling implications of different scores. The RIF is being actively used by the UK partner for these functions - in association with a range of governmental and local bodies.
The implementation process has been on-going, both on-site and remotely. Other partners have opted to implement specific modules from the RIF system and develop them in tandem with their present system objectives. The Dutch, Swedish and Spanish partners are implementing the system in an 'as is' state according to the system profile developed by the UK partner. The Finnish partner will also implement the UK RIF and compare the RIF to the existing SMASH system.
Phase III protocol
Evaluation of implemented systems for point-source analyses and disease and exposure mapping using country-specific case studies
The Danish partner will test the possibility of using routine health and population data for a study on the occurrence of cancer in a population exposed to airborne carcinogens from an aluminium recycling plant (as well as an incinerator and a metal recycling plant). The possible impact of exposure to airborne dioxins on total cancer incidence will be assessed. Exposure in the surroundings of the plant will be modelled, and concentric circles around the plant at various distances will be defined. Cancer risk in the defined areas will be computed. The results will be important for the public health work: if an excess cancer risk is found, preventative measures will be taken based on the results of the study.
The Finnish partner will investigate the possible increase in cancer risk following exposure to chlorophenols and PCDD/F emanating from a heavily contaminated river. Total cancer, lung cancer, breast cancer, sarcoma, myeloma, and lymphoma will be studied. It is presumed that PCDD/Fs are mobilised from river sediments and accumulate in nearby residents either via contaminated drinking water or via the food chain. The exposure assessment will be based on the distance of the place of residence from the river and from the Gulf of Finland. The extremely high amounts of PCDD/F in the river are a potential public health problem. If the results are positive, more specified studies are needed to assess the relation between PCDD/Fs and cancer, in order to apply relevant preventative measures. If the results are negative the population close to the river can feel reassured.
The Spanish partner will perform three case studies to evaluate the usefulness of the implemented system. Breast cancer incidence in the province of Granada, 1985-1996, will be mapped, using information from Granada Cancer Registry, covering 168 municipalities and 790,151 inhabitants. A RIF module adapted to Valencia and Granada (Spain) will be used, and smoothed maps of breast cancer risks will be produced. In Valencia, the relationship between nitrate concentration in drinking water and cancer mortality will be assessed, as well as the possible relationship between calcium and magnesium concentrations in drinking water and cardiovascular mortality, using data on water quality and cancer mortality for 539 municipalities. Smoothed maps of the relevant variables will be produced using the RIF. Relationships between risk factors and mortality rates will be explored by comparing populations at different risk levels within the RIF methodology. Results from the three case studies will provide guidelines to health policies for disease prevention and medical care facilities.
The Swedish partner will test and illustrate the capability of the implemented RIF as a tool for disease mapping and description of disease occurrence. The occurrence of acute myocardial infarction (AMI) in relation to social and socio-economic determinants in the Stockholm region will be studied, and risk estimates obtained from this ecological (disease mapping) approach will be compared with results, based on individual data, obtained from a large case-control study. This will be a collaborative effort between the Swedish and the UK partners. Information on various environmental factors (such as ambient air pollution or traffic noise) may also be geo-referenced and added to the database, as well as life style factors such as smoking. The usefulness of the system in health planning and health improving strategies will be assessed.
The UK partner will investigate cancer incidence in areas exposed to high levels of bromate. High levels of bromate were discovered in local water supplies in the Hatfield area (North of London), as well as private boreholes, likely to have come from a chemical plant manufacturing sodium and potassium bromates. Incidence and relative risk of selected cancers (all cancer, peritoneal, thyroid, kidney and bladder cancer as well as leukaemia) in the affected area will be computed. The population under study will consist of two areas: enumeration districts (EDs) falling within contaminated water supply boundaries, and an area containing EDs whose population centroids are included within a 7.5km radius of the old plant. There is great public concern within the locality. If no link is found between bromate and cancer, the population can be reassured, whereas positive findings will have much wider public health implications.
The Irish partner will work with the other EUROHEIS partners to examine and improve the performance of proposed measures of person and area level deprivation (developed during the 2nd phase of the project) in their chosen application areas. A key component of any spatial analysis of the health effects of environmental exposures is control for possible confounding by differences in deprivation between areas. A particular emphasis will be on an assessment of the comparative performance of the different components of the proposed deprivation indices between the partner countries.
In addition, the Irish partner will monitor congenital anomalies in relation to teratogenic exposure in Ireland, taking into account indicators of social and material deprivation. Ever since the thalidomide tragedy, one of the prime reasons for information systems to be developed concerning congenital anomalies has been their use for early warning of new or changing teratogenic exposures. The sensitivity, specificity and timeliness of monitoring now in place in Ireland (North and South of the Border) will be examined. The RIF system will be used to improve monitoring in time and space with respect to selected, environmentally sensitive, congenital anomalies. In particular, the quality and availability of indicators of deprivation at the individual level and the small-area level, and their usefulness in the RIF, will be evaluated in this work.
The Italian partner will apply model-based methods for Health Impact Assessment (HIA) to data on environment and health in selected European countries. The work will analyse data of the kind that is normally used for conducting HIA exercises (i.e., population-based routinely collected data), at the small area level. Methods for air pollution HIA will be developed in collaboration with a working group within the APHEIS project, co-ordinated by WHO-ECEH Bonn.
The methods for HIA developed in the second year of EUROHEIS are based on models incorporating components for exposure-response function, exposure profiles and variability, existence of susceptible subgroups as well as latency time and its variability. In addition, the models will make allowance for the possible sources of uncertainty using confidence limits of the exposure response and errors in the exposure measures. Mortality associated with ambient air pollution will be used to illustrate the HIA procedure, taking advantage of collaboration with the APHEIS project.
An end of project conference is to be held in Sweden (March 2003). The conference will focus on the use of the EUROHEIS RIF for public health. The system will be demonstrated, partner countries will present results from the case study evaluations, and external evaluators are invited to give their opinion of how the system can be used in future applications.
The final report to be delivered in August 2003. END OF PROTOCOL