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Environmental Environmental Epidemiology Epidemiology

on small on small areasareas

Ph. D. Alessandro Menegozzo

Agenzia Regionale Prevenzione Protezione Ambientale Veneto ( Italy ) www.arpa.veneto.it, email : svea@arpa.veneto.it

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BackgroundBackgroundEnvironmental epidemiology studies environmental risk factors and their impact on the health of exposed people;These factors may be natural or anthropogenic The risk factors derive from the people’s exposure to chemical, physical or biological stressors.The stressors come from point, line or area sources and reach the population by way of matrices ( air, water, soil, foods and space for electomagnetic waves ).

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Background (cont.)Background (cont.)The environmental risk adds or synergically

interacts with the basic risk of contracting an illness.

The environmental risk is as great as is exposure and individual physiological and anamnestic susceptibility.

The exposure to environmental risk factors may occur in an external environment (outdoor air ) or an internal environment (indoor air ).

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Environmental Epidemiology Environmental Epidemiology ObjectivesObjectives

Environmental Epidemiology assesses the added risk

( real or potential ) to the population exposed to environmental pollutants with the purpose of identifying the sources responsible for the pollution.

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The added risk from environmental factors interacts with non environmental risk factors:

Behavioural (smoking, drugs, alcohol abuse)

Socio-health (hygiene, nutrition, stress)

Genetic (hereditary susceptibility)

Anamnestic (previous diseases and medication)

Physiological ( age, sex, pregnancy, weight, height and respiration)

Professional exposure

Risk factorsRisk factors interaction interaction

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Why environmental Why environmental epidemiology on small areas?epidemiology on small areas?The complexity of interaction among risk factors hinders the risk assessement with conventional statistic tools used for large populations.

We have to study the disaggregate non sampled and territory related data to indentify a clusters of increased incidence of disease and then filter from them cases with non environmental risk factors.

This is only possible for small populations living on small areas concerned with a small number of risk factors.

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ProblemsProblemsThe small areas considered must be sufficiently populated for the clusters significance, especially for stochastic damages.

We have to make use of all computerised databases : territorial, private, health, and environmental.

During data transfer and assessement, privacy must be guaranteed

The health data needs to include family, physiological, pathological, behavioural and occupational exposure and mobility data .

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SolutionsSolutionsIn low population density areas, the health

stochastic environmental damages is very little.

All the institutions have adequate computerized database systems.

It is possible to use the private data without access to subjects names on screen.

We may obtain the informations on the environmental risk factors from questionnaires administered by the family doctor.

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Necessary resourcesNecessary resources and collaborations and collaborations

Territorial, health and environmental institutions have to form a coordinated operative team.

The databases have to be to coordinated on work station capable of building, to managing and to querying the geodatabases.

The clusters filtering process requires the elaboration and administration of questionnaires through family doctors.

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Operative process Operative process A)Identify the suspicious sources and risk areas

from emissions register, environmental data and modeling

B) Choose a study area, including risk areas, with a population of suitable dimensions

C) Build the thematic map of the study area

D) Acquiring and georeference the road, socio-health and personal databases

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Operative processOperative process( continuation )( continuation )

E) Identify possible health damage and environmental diseases

F) Show evidence of the environmental disease clusters associated with selected factors

G) Filter the clusters from non environmental risk factor cases

H) Verify the filtered clusters by biochemical methods on tissue

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A+B ) Study area identificationA+B ) Study area identificationExamine the emissions registers and environmental data in air, soil, foods, water and space.

Identify the hazardous substances and stressors carried by matrices.

Fate and diffusion modeling of hazardous substances and stressors.

Risk areas identification.

Link the risk areas with synergic stressors.

Choose a study area including risk and stressor free areas.

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C+D) Geodatabase buildingC+D) Geodatabase building

Acquire raster map of study areaMap vectorialization for residential,

production and service structure and sensitive sites

Acquire personal and health databases on the map layers for geodatabase building

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E) Possible E) Possible environmental diseasesenvironmental diseasesReduced fertility, spontaneous abortionLower birth weight, malformationsRespiratory, gastroenteric and kidney diseasesImmune, endocrine and neoplastic diseasesNervous and mental diseasesDermatological and sense organ diseasesInfectious and parasitic diseasesCardiocirculatory and muscle-skeleton diseases

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F) clusters identificationF) clusters identification

Health data layer may show clusters with a greater incidence of disease caused by the environment causes

G) clusters purificationG) clusters purification

Patients ( or at relatives in case of death ) of these clusters have to be given a questionnaire to identify and exclude non prevalent environmental cases

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G) Anamnestic G) Anamnestic questionnaire for cluster filteringquestionnaire for cluster filteringFamily anamnesis ( disease cases in relatives

not living in the cluster )Work and behavioural anamnesis ( exposure to

professional and behavioural risk factors )socioeconomic, pathologic and pharmacological

anamnesis ( factors modifying exposure, susceptibility or prognosis )

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H) Clusters biochemical checkH) Clusters biochemical check

Even the most careful cluster purification not confirm the relationship between environmental factors and diseasesTherefore we must research metabolic markers, i.e.matabolites of pollutants, in tissues ( hairs or nails ) or biological fluids ( blood, urine, saliva and mother’s milk ) in affected people or in random sample for comparison with subjects outside the cluster. 17

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Latency problemsLatency problemsThe neoplastic, reproductive and development

diseases begin a long time from exposure.therefore the emission sources have to be

considered taking latency time into account.The affected subjects have verified for

different exposure for home changes.In the course of latency time, the health risks

cannnot be prevented, therefore a risk estimation of possible exposure and effects is better than the epidemiological survey of disease cases.

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Environmental risk Environmental risk communicationcommunication

The communication should be sincere, jargon-free, in time and with preventive value :

Communication should include: method description, uncertainty factors and scientific bibliography.

The assessement receivers who manage the environmental risk take responsability for using the assessement in environmental protection and health prevention decisions.