Human World

Your geography is linked to your health

Introducing geomedicine, an emerging concept in health care. Someday, when you visit a doctor, you might tell him or her your “place history” – how where you’ve lived, or your personal geography – might have affected your health. Bill Davenhall is with the geographical software company Esri, a major producer of Geographic Information Systems (GIS) software. The company helps make it possible to capture, analyze, and present data linked to geographic locations. Davenhall and others at Esri believe “place history” brings a new and necessary dimension to 21st century health care. Davenhall spoke with EarthSky’s Jorge Salazar.

Tell us about geomedicine. What is it exactly?

It’s quite simply the linking – through geography – of the vast amount of public health knowledge to personal health. Geography then becomes the linchpin that brings our personal health into focus, using all the public health knowledge that’s relevant to our personal environment.

How can knowing more about “place history” help improve people’s health?

The whole concept of place – where you work, play or live – is critical to health. Doctors ask you about your medical history, drug history, surgical history, perhaps even your social history. But, so far, they don’t ask about your place history. That belies the fact that you might have lived near all sorts of hazardous, toxic materials that impact your health.

A famous example is Love Canal in Buffalo, New York [which was evacuated in 1978]. There was a great deal of chemical contamination of the water supply systems in and around Love Canal, the result of millions of barrels of buried chemicals. If you were born and grew up near the site – say, spent your first 15 years of life there, then you moved to Southern California – it might take a physician a little longer to try to figure out why you’re having thyroid trouble, especially if you are pregnant. While a lot of knowledge about the harmful impacts of toxic material is known by doctors, it’s not necessarily easy to understand exactly where these sites are located or how close you might have lived to them.

You’ll also find examples in diseases like breast cancer, prostate cancer or Parkinson’s disease. They have higher incidence in certain parts of the United States. There has been a lot of research in this area. Anyone that wants to comb through PubMed or any of the scientific literature can begin to see patterns that reflect geographic variability in both the incidence and prevalence of these kinds of diseases and are of high concern to the public. You begin to see that the health concerns in one part of the U.S. are not a priority in another section of the U.S.

Geography is a tremendous tool that doesn’t get used in medicine today. There are very few medical schools that actually teach about geography, let alone about the geographic variability of disease. Medical geography has been taught for some time in selected fields of primary care. While medical geographers study the impact of medicine on the health of populations, this knowledge never gets driven to what I would call the point of service – inside the doctor’s office. Geomedicine needs a “place test,” similar to a blood test, where the physician has some heads-up as to what would be panic values – in other words, test results that would lead the doctor toward one treatment versus another. Your place history becomes another vital piece of information that can be brought into the diagnostic setting.

Geomedicine – linking your personal geography with the vast amount of public health data – is an essential mechanism that’s going to bring that kind of knowledge into a very tight focus around your own personal health issues.

What if you know there’s air and water pollution where you live? What can you do with this knowledge?

The first thing people can do is get informed about where toxic sites are located geographically. People can learn about what chemicals are in water they drink, or about pollutants in the air they breathe. So on one level, using geomedicine, people have greater transparency into what chemicals are where. It gives them the knowledge they need.

The second thing people can do is push to get the toxic materials cleaned up. When people learn of the existence of certain kinds of pollutants, contaminants, or toxins that are harmful to human health, they tend to want to organized and get places cleaned up.

The third thing people can do, of course, is to move. Many people make conscious decisions to move to places that better suit their health. The practicality of geomedicine is this: if you know that you’re exposing yourself to certain kinds of toxic materials and environments, you’re going to avoid them. So, for a lot of people, geomedicine will not only be a diagnostic tool but a prescriptive tool for helping people decide to move to a safer and healthier place.

Tell us more about Esri’s free online resource called My Place History.

Esri developed a simple application to help people understand the relationship between their environment and how something like toxic materials might impact their health. We produced an application that runs on the iPhone, iPad and the PC. It allows you to inventory your own individual place history – where you have lived or worked. You can put as many places into the application as you need to, and as detailed an address as you have. My Place History will become a geographically accurate record of where you have lived.

The application then searches of all the toxic release inventory (TRI) sites that the Environmental Protection Agency (EPA) collects, and has been collecting since 1987. It returns a sharable report that documents the proximity of all your places to toxic release inventory sites for 2009.

The application makes no assumption about the degree of risk or exposure you might have had, or if in fact your health problems are caused by any of the chemicals that are listed in your My Place History report. It’s just bringing back pieces of information that are related by geographical proximity. While there are over 80,000 known chemicals, the EPA only monitors the release of about 200 that are known to be dangerous at certain levels to humans. The TRI data, of course, is made freely available by the EPA. Similar databases exist for many of the industrialized nations of the world. Some countries will focus on air quality information, while others on water quality information. The U.S. EPA as well as the National Library of Medicine also makes this data easily accessible to the public through a web site called

When you generate your own report from My Place History, you can share it with your friends and family. Hopefully, you might send it to your doctors, so they have even a better understanding of where you might have been exposed to harmful materials in your various environments. And while it doesn’t mean that these chemicals are causing your health problem, your doctor will have some new diagnostic clues.

What’s the most important thing people should know about geomedicine?

I would say we’ve achieved the first hurdle, which is bringing attention to the fact that there is geographic data available that can be used in meaningful ways in the doctor’s office. And now we need to get on to the hard part. That is, how do we craft this information to be a really useful in a diagnostic workup by a physician?

So we have begun. We’re seeing interest from medical communities, academic health science centers – places where physicians typically adopt new ideas.

If I could leave people with one message, it would be that everything is connected. Everything that occurs around us – everything that we do in reaction to our environment – is all connected. Geomedicine isn’t the only answer. It’s not a panacea to every possible thing that you could think of in improving human health or well-being. It’s just another piece of the puzzle that needs to be put into its proper place so that we get greater value in the final equation.

August 18, 2011
Human World

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