May 6, 2002

Although many people have used Geographic Information Systems (GIS), few could explain what they are. In the recently published book GIS and Public Health, two geography professors, Ellen Cromley and Sara McLafferty, explain the technology and explore its importance in understanding and preventing diseases.

GIS are computer-based systems that allow users to integrate and analyze geographic data, write Cromley, a professor at UConn, and McLafferty, a professor at the University of Illinois at Urbana-Champaign. Well-known technologies related to GIS include global positioning systems and mapping software. "Anyone who has ever logged onto the Internet and used Mapquest is using GIS," Cromley says.

Though the technology has been used in the public health field for more than a decade, the book by Cromley and McLafferty is the first to examine the use of GIS in the health arena. The two women are both medical geographers and have insights into how public health practitioners are applying GIS.

"This book is a way to train the next generation of public health workers," Cromley says. "It's also an opportunity for us to summarize our own experience."

The authors dedicate several chapters of the book to a review of GIS and mapping. The remainder of the book explores how GIS can be used to

analyze different types of diseases and disease clusters - unusual concentrations of health events, and to locate healthcare centers. Other chapters summarize community-based GIS health studies.

The book is an important addition to the GIS field because it highlights the technology's use in public health.

"It's about intervention," Cromley says. "We need to know where people are sick and what we can do to prevent exposure to harmful agents."

For example, in New York State, a water source was contaminated with an agent that's harmful to newborn children. By using GIS, healthcare workers were able to plot where newborn children lived and notify their parents not to use the water when making their children's formula.

In Hartford, healthcare practitioners studied the location of residential house fires and identified a neighborhood with a high number of them. Workers went into the neighborhood, checked residents' smoke detectors to make sure they were operable, and gave smoke detectors to people who didn't have them.

"It's not enough to look at policy," Cromley says. "GIS can provide people with detailed information about health problems in their area, with an eye toward intervention."

Cromley is currently using GIS to study the incidence of Lyme disease in Weston and Westport. By studying where people who have the disease live, work and play, Cromley hopes to eventually lower the number of future cases.

"As the links between the GIS and public health communities expand," Cromley and McLafferty write, "mapping, viewing, and analyzing geographically based health information will occupy an even more central position in efforts to improve performance of essential public health activities and to promote community health and well-being."