March 4, 2022 -- People who live in neighborhoods that are more walkable are much more physically active and less likely to gain weight or get type 2 diabetes or high blood pressure, researchers concluded after reviewing the results of dozens of previous studies.
Gillian L. Booth, MD, and Nicholas A. Howell, MD, both from the University of Toronto, Ontario, Canada, used findings from more than 170 studies that looked at how the "built environment" affects physical activity, obesity, and diabetes. They published their results in the journal Endocrine Reviews.
The built environment includes street layout, residential vs. commercial zoning, bicycle paths, and public transportation, Booth explained in an email to WebMD.
When suburbs were first developed, Booth noted, zoning laws separated residential and commercial areas, so people had to travel farther to reach grocery stores or the bank, and car use went up.
Denser neighborhoods, where people can walk or ride a bicycle to public transit, are associated with greater physical activity and better health.
But even if the built environment is walkable, Booth said, if there are many nearby fast-food restaurants but no grocery stores -- referred to as a "fast-food swamp" -- or if the streets are not safe to walk on, the health benefits can be decreased or canceled out.
Physical Activity, Obesity, Prediabetes, Diabetes, and Blood Pressure
The following studies are examples of how neighborhood walkability has a positive effect on physical activity and the risk of being overweight or having obesity, prediabetes, diabetes, and high blood pressure:
- The International Physical Activity and Environmental Network study of 14 cities in 10 countries found that people in the most walkable neighborhoods (with the best transit options and access to parks) spent roughly 1 to 1½ hours more per week being at least moderately physically active, compared to people in the least walkable neighborhoods.
- In a study of residents in nearly 9,000 neighborhoods in Ontario, young and middle-aged adults who lived in the most vs. the least walkable neighborhoods were less likely to be overweight or obese (43% vs 53%).
- In a study of 1.1 million adults in 15 cities in Ontario, Canada, who had normal blood sugar, people living in the least vs. most walkable areas had a 20% higher rate of getting prediabetes over a period of 8 years. The risk varied in different race/ethnicity groups.
- A study of 1.6 million adults living in Toronto, Ontario, found that people living in low vs. highly walkable areas had a 30% to 50% higher likelihood of getting diabetes within 5 years.
- In another Canadian study, moving from an unwalkable to a highly walkable neighborhood was linked to a 54% lower chance of being diagnosed with high blood pressure within 10 years.
Air Pollution, Crime, Fast-Food Swamps, Crumbling Sidewalks
"Walkability appears to be protective against metabolic diseases," Booth said, though "there may be other, more important factors in an environment that affect health."
People living in downtown, inner-city neighborhoods in the U.S. and Canada often have lower incomes or live in fast-food swamps, also known as “food deserts,” which are all linked to a greater risk of obesity and diabetes.
High crime rates, fewer connections between neighbors, and poor infrastructure (such as sidewalks in disrepair) make it less safe to walk.
In one of the studies Howell and Booth had done previously, they found that high walkability appeared to no longer protect against diabetes and high blood pressure in areas that had high rates of traffic-related air pollution or were fast-food swamps.
"Not every neighborhood can be rebuilt,” Booth said, but “we can add elements such as bike and walking paths, safe pedestrian infrastructure, more accessible and cleaner public transit to allow people to engage in greener and more active forms of transportation," which are linked with health benefits.