Update: spatial aspects of epidemiology: the interface with medical geography.

Medical geography and epidemiology share the common goal of understanding disease processes and improving methods of health interventions. While they share a common history, the fields have diverged and developed different, often complementary, approaches to the same types of problems. Medical geography differs from epidemiology in its underlying focus on applying the concepts and methods of geography to investigate health-related topics (1). Much like other subdisciplines within its field, medical geography attempts to integrate concepts and methods from various social, physical, and biological sciences to create a unique specialty. Throughout much of its development and continuing to the present, the focus of medical geography remains very much on an ecologic perspective of health. Its emphasis is on the interplay of the behavior of humans and the environment to generate observed health outcomes so that, in addition to the traditional issue of spatial variation in disease incidence or prevalence, research related to understanding variation in individual risk perception and movement patterns has come into play (2, 3). Coupled with this is the practical application of these research issues, such as the optimal structure and network design of health care delivery systems (4). In contrast, epidemiology is purposive for health promotion and disease prevention, with a focus on providing paradigms for the investigation of specific health problems and providing etiologic explanations for these problems, especially from a biological perspective (5). From a medical geography perspective, epidemiology provides an additional rich source of methods, concepts, and information that can be incorporated to study problems of interest.