Studying diabetes with GPS

For many, the GPS systems built into our smartphones are nothing more than a convenience when we are trying to find the closest gas station or a helpful tool when we are lost.

However, Sean Doherty, a geography and environmental studies professor at Wilfrid Laurier University, saw potential in these seemingly mundane tools as devices which could enhance the health of individuals with diabetes. His research paper entitled “Exploring Blood Glucose Level over Geographical Space” outlines the study he conducted regarding the trends of glucose levels in the day to day travels and activities of people with diabetes.

Doherty initially dabbled with the idea of using GPS systems to track people in urban studies he was conducting. He soon realized, however, that this provided an accurate depiction of human exposure — namely where they were spending time and what activities they were engaging in.

“I realized it has direct implications for your health,” he said, speaking to the usefulness of the GPS data collected.

These systems could be used to track patients with diabetes to produce a precise depiction of their daily activities.

When speaking with doctors at the Toronto Rehabilitation Institute, they were largely interested in the objective information about their patients that this system would provide them with.

Two different systems were used to gather information: one being a GPS which collected data every second, and the other being an accelerometer which collected data 25 times a second.

“The accelerometer is like a pedometer,” Doherty explained. “Except it not only measures up and down, but also side to side as well as back and forth motions.”

With the data collected, Doherty had an illustration of where the individual was, what they were doing and whether their glucose level was being affected. Doherty explained how he started by producing a map of the person’s glucose every five minutes as they moved around in space.

“That turned out to be incredibly novel. No one’s ever done that,” Doherty imparted.

This map brought a new concept, allowing Doherty to examine the question: does the environment people are in effect their glucose levels? However, his findings revealed that it’s very individualistic.

“I was trying to make the point that, in different locations, people’s lives had different effects on their glucose,” he explained.

There was variation, however. While being far away from home may cause one person’s glucose to rise significantly, it may cause another’s to drop, and another may experience no changes. Therefore, the study’s findings couldn’t be generalized.

Rather, Doherty says that health geography is applicable in other ways. “What this leads us to discovering are real behavioural changes that will improve people’s health over time,” he noted, going on to explain how it’s the accumulation of factors that cause adult onset diabetes to develop.

If these factors could be identified and the patient advised to reduce them, the diabetes may be avoided. “At the end of this paper I can definitively say that at best it’s going to lead to a new way of managing the disease,” Doherty said.

For example, if it is identified that one particular patient’s glucose levels rise when they are far away from home, then doctors can engage them in conversation about it.

“Now let’s say I give the person with diabetes a smartphone with an application that looks specifically for times when they remain at one location for more than an hour,” he explained.

The idea is that when it identifies that situation, it warns them that they should prick their finger and test their glucose level.

Mostly Doherty is devoting his time to creating algorithms that could analyze this data to make it easier for healthcare professionals. While this is a complicated process that requires the consideration of many factors, Doherty believes this study was the first step.

“There’s a lot of work to do,” he said. “But this paper is drawing attention because it’s showing promise.”

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