"If you have fewer opportunities for physical activity in your daily life, then you may gain more weight...and you're also more likely to develop diabetes," said Dr. Gillian Booth, the lead author and a researcher at St. Michael's Hospital in Toronto.

Booth said earlier studies have looked at potential links between diabetes and the pedestrian-friendliness of neighborhoods, and have found similar connections - but that research took only a snapshot in time, making it difficult to determine which came first, the neighborhood style or the elevated diabetes risk.

With the world's population increasingly concentrated in cities, Booth and her colleagues wanted to further tease apart the relationship between urban environment and health.

New immigrants from less developed countries to urban areas like Toronto are at particular risk for falling into a sedentary lifestyle and falling prey to Western lifestyle diseases, Booth's team notes in the journal Diabetes Care.

To assess whether neighborhood walkability influences the likelihood of developing diabetes, Booth and her colleagues collected information from a health registry on nearly all adults living in Ontario, focusing on the 1.2 million who did not have diabetes.

For five years, from 2005 to 2010, they tracked how many people went on to develop diabetes.

They also mapped out where the people lived, and categorized them according to the walkability of their community.

The most walking-friendly places are more densely populated, have streets that connect with one another, and have stores, schools, work places and other destinations within walking distance of homes.

The least walkable neighborhoods are more sprawling, with disjointed streets and long distances from homes to shopping centers and schools.

The researchers found that, among long-term Ontario residents, 6,003 out of about 210,000 of those who lived in the least walkable neighborhoods developed diabetes, compared to 5,290 out of 245,000 who lived in the most walkable areas. This corresponds to a 32 percent increase in diabetes risk for those who live in the least-walkable areas.

Among new immigrants to the region in the previous 10 years - most foreign born - more than twice as many people in the least-walkable neighborhoods developed diabetes as in the most-walkable areas, translating to a 58 percent increased relative risk for those in the walking-unfriendly neighborhoods.

The study did not show that people actually walked less in those neighborhoods, but Dr. Ethan Berke, associate professor at the Geisel School of Medicine at Dartmouth in Hanover, New Hampshire, said that people who live in pedestrian-friendly communities tend to be more physically active.

Although the new study could not prove that walking was responsible for the lower diabetes risk in certain neighborhoods, Berke, who was not involved in the research, thinks that something in the neighborhood environment is likely responsible for the findings.

"Whether that's due to social capital or opportunities for healthy behaviors, such as physical activity, or opportunities for access to healthy foods isn't clear, because a walkable neighborhood is usually associated with a lot of those things," Berke said.

Other research has linked walking to a lowered chance of having diabetes. One recent study showed that people who are at high risk for diabetes and who walk more are less likely to ultimately develop the blood sugar disorder (see Reuters Health story of June 28, 2012).

Booth said that aside from the weight benefits of physical activity, exercise itself might help ward off diabetes by improving the body's use of insulin.

On the higher risk seen among recent immigrants to Canada, Booth speculates that immigrants from a very different environment may be more sensitive to the lack of opportunities for activity than residents who have lived in an area longer.

"We need to rethink how we're designing neighborhoods and think about it from the perspective of what impact it has on health," she said.

Berke agreed. "Where we live has a huge impact on our health, and I think this study adds to the evidence that where you live matters an awful lot in how you get sick and if you get sick," he said.

SOURCE: bit.ly/Qsw1xK Diabetes Care, online September 17, 2012.

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