Geographical Variation of Non-Communicable Diseases and Environmental Risk Factors: Application of Bayesian Modeling and GIS

The incidence of Coronary Heart Disease (CHD) and childhood type 1 diabetes (DM1) is among the highest in the world in Finland. Also the occurrence of DM1 and CHD are known to have a large geographical variation in Finland. The recent advances in GIS, availability of geo- referenced data and developments in spatial methodology are valuable tools for exploratory analysis, testing and generating hypothesis and searching for unusual clustering. The aim is to present recent developments in methodology of geographical epidemiology research and to demonstrate its use in small-area study on DM1 and AMI in Finland. Data CHD: Data on non-fatal definite acute myocardial infarctions (AMI) and mortality data (CHD mortality) included 19,000 cases from the cross- section years 1983, 1988 and 1993. The mid-year number of men aged 35- 74 years in each cross-section year was used as a denominator. DM1: Data on the incidence of childhood Type 1 diabetes for the period 1987-1996 included 3649 cases. The mid-year number of children aged 0- 14 years in each cross-section years 1987, 1989, 1991, 1993 and 1995 was used as a denominator. Water macro- and trace elements: The geochemical data on nitrate (NO3), zinc (Zn), water hardness (dH) and some other elements of the ground water were obtained from the hydrogeochemical database of the Geological Survey of Finland and interpolated onto a regular grid.