1. Use of Exposure Simulation Models and GIS-integrated health registers EUROHEIS/SAHSU Conference March 2003 Östersund, Sweden 30 – 31 March 2003 Dr. Arne Poulstrup & Dr. Henrik L. Hansen Regional Public Health Office Southern Jutland and Funen, Denmark Vedelsgade 17 A, DK – 7100 Vejle E-mail: arne@vej.eli.dk

2. Medical Office of Health, Province of Vejle, Denmark Case Study: Cancer development in an urban population due to airborne dioxin, assessed by use of an exposure simulation model and a GIS-integrated health register

3. Medical Office of Health, Province of Vejle, Denmark Prevailing problems concerning environmental exposures and health outcomes: Levels of exposure of individuals are often unknown Areas of exposure are difficult to demarcate Time of exposure is difficult to determine Hence: the number of individuals in time and space exposed for certain levels of environmental hazards are rarely possible to identify precisely

4. Medical Office of Health, Province of Vejle, Denmark A solution to environmental exposure level assessment: Simulation models for exposure can be used, like atmospheric dispersion models for airborne pollution: A Danish Gaussian plume model (OML) simulates the dispersion of plumes, incorporating features like Heights of one or more stacks (more sources) Smoke emissions, velocity and temperature High rise nearby buildings, surrounding terrains Atmospheric conditions, like prevailing wind directions, wind temperatures, fall of rain, snow etc.

5. Medical Office of Health, Province of Vejle, Denmark Case Study: Simulated immissions of hourly conc. of dioxin, using OML, has been geo-coded and layered into GIS. Colours represent conc. of dioxin

6. Medical Office of Health, Province of Vejle, Denmark A solution to the demarcation of the exposed population : The population at risk is identified by applying all addresses (inclusive historical) into GIS, using geo-coded addresses And by linkage of all individuals to these addresses using the unique CPR number (10 digit number in Central Population Register [Civil Registration System])

7. Medical Office of Health, Province of Vejle, Denmark All addresses since 1986 have been applied as a layer in GIS. Each address contains info on migration of every indivi- dual who lives or has lived there, as well as duration of stay

8. Medical Office of Health, Province of Vejle, Denmark The boundaries of the dioxin exposure (simulated immission of dioxin > 0 pg/h/m 3 ) is then used to demarcate the exposed area. Polygon 1.

9. Medical Office of Health, Province of Vejle, Denmark Polygon 2: area with dioxin conc. ≥ 3 pg/h/m 3

10. Medical Office of Health, Province of Vejle, Denmark Polygon 3: area with dioxin conc. ≥ 4.5 pg/h/m 3

11. Medical Office of Health, Province of Vejle, Denmark Polygon 4: area with dioxin conc. between 0 -3 pg/h/m 3

12. Medical Office of Health, Province of Vejle, Denmark Polygon 5: Area with dioxin conc. between 3-4.5 pg/h/m 3

13. Medical Office of Health, Province of Vejle, Denmark Solution to exposure time assessment: Number of records are reduced to number of individuals Only individuals who have stayed more than two years are selected Only individuals relevant for selected health outcome, e.g. cancer are selected

14. Medical Office of Health, Province of Vejle, Denmark The selected exposed individuals in time and space are then linked to the National Cancer Registry using the CPRs. The map shows the diagnosed cancers (in dark blue) among all exposed individuals (in yellow) in polygon 1

15. Medical Office of Health, Province of Vejle, Denmark Same procedure is used to select and demarcate the control area: Selection of a suitable area (non exposure) Selection of sufficient number of controls Selection of individuals who have stayed sufficient time in the area

16. Medical Office of Health, Province of Vejle, Denmark Final analyses of the case area will include the different bands of exposure (from 0 – 6 g -12 of dioxin/hour), and in the analyses of health outcome (i.e. “all cancer”) in the selected open cohorts, the following confounders will be controlled for gender ratio, age stratas and at least one socio-economic variable

17. Medical Office of Health, Province of Vejle, Denmark So far analyses have been made, comparing cancer rates from the exposed area from the period 1986 – 1998 with national cancer rates, and: SIR (Standardized Incidence Ratio) and IRR (Incidence Rate Ratio) showed no excess of cancer in the area of exposure

18. Medical Office of Health, Province of Vejle, Denmark Financially the study has been supported by grants from: European Commission,DG for Health and Consumer Protection Ministry of Health, Denmark