Application of geographical information systems (GIS) in epidemiological studies using the example of the ISAAC study Munich

Geographical Information Systems (GIS) are increasingly applied as modern tools for analysis and visualization of health-related spatial data, especially in epidemiological research. GIS are used by medical researchers and executives in the public health service. A community-based survey was conducted according to the phase II protocol of the International Study of Asthma and Allergies in Childhood (ISAAC) in Munich. The spatial patterns of disease incidence were analysed and related to exposure data by GIS. The prevalence study on fourth-grade pupils (n=3354) and school beginners (n = 2890) was conducted during the school term 1995/96 in Munich. Parental questionnaires and measurements of lung function and immunological parameters were used. The questionnaire data were integrated in a GIS database. In this paper we discuss methodological aspects of GIS-based spatial analysis related to epidemiological data. In addition, we investigate whether there were spatial clusters of children with wheeze in the last 12 months of a magnitude unlikely to occur by chance and which could indicate local health risks. The study was based on permutation tests where global and local methods were applied. No spatial clusters of children with asthma symptoms were identified in the city of Munich.