Type 2 diabetes may not be contagious, but it certainly appears to be spreading. In 1958, the prevalence was 0.9%. By 2000 it had climbed to 4.4%, and it’s projected to hit 7.2% in 2050.
What accounts for this? Perhaps it’s the way residential neighborhoods have evolved to accommodate car rides to fast-food restaurants instead of walks to corner grocery stands.
A study being published today in the Archives of Internal Medicine calculates that people who live in neighborhoods that are conducive to physical activity and healthy eating have a 38% reduced risk of developing diabetes compared with people who don’t.
The study looked at 2,285 adults who lived in Baltimore, the Bronx in New York and Winston-Salem, N.C. As participants in the Multi-Ethnic Study of Atherosclerosis, they gave researchers information about where they lived, what they ate, their medical history and exercise habits. Over the five years of the study, 233 were diagnosed with Type 2 diabetes.
Drexel University epidemiologist Amy Auchincloss and colleagues studied the data to see what – if anything – set the diabetes patients apart from the rest of the volunteers. After controlling for factors like age, sex, income, family history, drinking and smoking, they found that people in the top 10% of neighborhoods for promoting healthy diets and physical activity were indeed less likely to become diabetic than people in the bottom 10%.
In some sense, the results aren’t terribly surprising, Dr. Mitchell H. Katz of the San Francisco Department of Public Health noted in an editorial accompanying the study. Diabetes rates were lower in the good old days before families could afford multiple cars and folks had to walk quite a bit to get to schools, stores and jobs. Home-cooked meals may have featured lots of butter, but they weren’t routinely served with a side of fries and refillable cup of soda. If there was a TV in the living room, channel surfers had to get up off the couch to change the station.
Correlation does not equal causation, of course. Perhaps people who value a healthy lifestyle choose to live in neighborhoods with bike trails and health food stores. Or maybe it’s simply that people who make more money can afford to shop at Whole Foods and visit the doctor for an annual checkup.
Doctors can’t do much about the genetic factors that might predispose someone to diabetes. But if public health experts identify ways to make neighborhoods healthier, we ought to give them a try, according to Katz.
“If we are to decrease the rates of type 2 diabetes, we need to change the environment in ways that make it easy for people to exercise and eat right as part of their daily routine,” he wrote. Some simple examples include: providing access to school playgrounds even after school is over for the day; widening sidewalks; painting bike lanes on roads; and establishing community gardens.
-- Karen Kaplan
Photo: Living by a farmers market is linked to a reduced risk of Type 2 diabetes. Photo credit: David Karp/For The Times