Geographic Information Systems and Health – New Tools for Old Problems

Overview of Special Section on Medical Geography

Beginning with the writings of Hippocrates (460 BC), who held that health and place are related, place has always been important to medicine (Hippocrates 1886; Meade and Earickson, 2000). Until the beginning of the 19 th century, medicine was concerned with geographic variations in air, water, soil, vegetation, animals and insects, diet, habit and customs, clothing, house types, economy and government. The emergence of germ theory specifically the idea of specific etiology – that microbes invade human bodies and cause alterations that produce disease – led to key developments in medicine such as vaccination and other modern technologies for fighting disease.

Disease mapping has provided important insights into geographic patterns of disease, risk, and mode of spread for centuries. The pioneering work of John Snow on cholera (Snow, 1855), provided insights that were subsequently used in the first scientifically based epidemic control. Since then, the field of medical geography – the study of geographic patterns of disease and health care facilities – has come a long way. As a subdiscipline within geography, Medical Geography has a relatively short history. Beginning with Jacques May, the “father” of medical geography who initiated the discipline in the United States in 1950 and wrote The Ecology of Disease (1958), the discipline has grown very rapidly.

Recent developments in technology and especially the challenge of emerging, reemerging infectious and degenerative diseases in a globalizing world have necessitated explosive growth in medical geography research. Paper maps have been replaced with digital maps in what is now called Geographic Information Systems. Descriptive speculation about disease has been replaced with scientific analysis of spatial patterns of disease including hypothesis testing, multi-level modeling, and multivariate analysis.

Medical Geography today draws on the concepts and techniques of geography, and epitomizes the interdisciplinary nature of the discipline. It provides an excellent bridge between the biomedical and social sciences and the application of GIS in health is particularly demanded because it provides unique insights for disease control. GIS provide a digital lens for exploring the dynamic connections between people, their health and well-being, and changing physical and social environments (Cromley and McLafferty, 2002). It permits identification and mapping of vulnerable populations, health outcomes, risk factors, and exploration of associations between them at varying scales. By making it easy to link disease data to other information about the environment including geographic distribution of risk factors, GIS provides a powerful tool for medical geographers.

The three papers in this volume provide a sample of the variety of work in Medical Geography at different scales. From infectious disease – HIV and Viral Hepatitis C, which are spread through exchange of bodily fluids such as sexual intercourse – to suicide, these papers use GIS to probe and provide insights into spatial patterns health and disease. Will Flanagan’s work on suicide and lithium concentrations fits beautifully into the burgeoning and exciting field of Medical Geology – the science dealing with the relationship between the geographic distribution of natural geological materials and processes and health (problems) in humans and animals (Selinus et al, 2005). The papers also reflect the important variety of scale for medical geographic research. While Flanagan and Hedrick work at the state level and cover the 254 counties in Texas, Enwright’s work is at the county level and focuses on spatial variations by zip codes in Dallas County. The approaches are similar – examine the spatial distribution of the disease, and using statistical analysis and disease mapping, attempt to explain the spatial pattern of the disease.

Although these are basically introductory analysis, each of these papers provides very useful insight for disease control and intervention planning. Flanagan’s analysis suggests that counties with lower groundwater dissolved lithium concentrations have significantly higher suicide mortality rates, particularly for Whites. Enwright shows that race/ethnicity, level of education and income are significant determinants of the HIV rate in Dallas County. This makes sense in light of national trends, but the zip codes mapping analysis provides an invaluable tool for clear communication and perception of risk areas for HIV. Hedrick’s work shows that population density is not a significant indicator of HCV rates in Texas, but race and gender are significant. Thus intervention efforts in Texas must focus especially on minorities in rural areas.

After working with these students, I am truly gratified and excited at the thought that Medical Geography is alive and well at the University of North Texas. It is truly exciting and gratifying to know that the future of Medical Geography is very bright.

References

  • Selinus, O. b. J. Alloway, J. A. Centeno, R. B. Finkleman, R. Fuge, U. Lindh, and P. Smedley. (2005). Essentials of Medical Geology. Burlington, MA: Elsevier Academic Press.
  • Hippocrates. (1886). The genuine works of Hippocrates (F. Adams, Trans.). New York: William Wood.
  • May, J. M. (1958). The ecology of human disease. New York: MD Publications.
  • Meade, M. S. and R. J. Earickson. 2000. Medical Geography. Second Edition. New York: Guilford Press.
  • Cromley, E. K. and S. L. McLafferty. (2002). GIS and Public Health. New York: Guilford Press.