By John Bohannon, ScienceNOW

If you’ve begun to pack on the pounds, your doctor may recommend that you get up and move around. But a new study suggests that it’s not just your body you should be moving. Researchers have found that relocating people out of poor neighborhoods can be as effective as drugs in reducing their chances of becoming overweight and developing diabetes.

The idea that neighborhoods have subtle but powerful effects on our health goes back at least to the 1920s, says Jens Ludwig, a sociologist at the University of Chicago Law School. “This question is one that I have been personally very interested in for a long time, partly because I live here on the South Side of Chicago [where] there are massive disparities in people’s life outcomes and well-being.” But how to tease apart the causes?

“Consider two low-income African-American 50-year-old women in Chicago,” Ludwig says. “One lives in Hyde Park,” an integrated middle-class neighborhood, “and the other lives in Washington Park,” a nearby but extremely poor and racially segregated neighborhood. “We see that the woman living in Hyde Park has better health,” Ludwig says, but is that due to the neighborhoods themselves or some difference between the women that led them to choose where to live? The only way to sort out cause and effect is to do a randomized trial, moving people around between neighborhoods and tracking their health over several years.

That is what the U.S. Department of Housing and Urban Development (HUD) did, and a team led by Ludwig has been analyzing the results. In an attempt to suss out a link between education, employment, and neighborhoods, HUD recruited 4498 volunteers from 1994 to 1998 living in public housing in cities across the country and randomly assigned them to one of three groups. The first group received rent vouchers that enabled them to move to middle-class neighborhoods—defined as having less than 10% of residents with incomes below the poverty threshold. The second group received the same vouchers to help with rent but stayed in the same neighborhoods. And the third group was a control that received no vouchers and stayed put. Researchers checked on everyone’s health at the start of the experiment and again between 2008 and 2010, measuring data such as height, weight, and the amount of hemoglobin in the blood bonded to sugar molecules, which is a diabetes indicator.

Neighborhoods matter, Ludwig’s team found. The health of people who received rent subsidies but did not move showed no significant improvement. But the people who moved to middle-class neighborhoods were about 5% less likely to be obese and show signs of diabetes than were people in the control group, the team reports today in The New England Journal of Medicine. “These are pretty big effects,” Ludwig says, “comparable in size to the long-term effects on diabetes we see from targeted lifestyle interventions or from providing people with medication that can prevent the onset of diabetes.”

The experiment clearly shows that the neighborhood effect is real, says Nicholas Christakis, a sociologist at Harvard Medical School in Boston who studies the effect of social ties on health, but the mechanisms remain murky. Is it the shops and restaurants, the parks and pools, he wonders, “or the people in a neighborhood that affect you most?” For example, Christakis says, the people who moved might have lost weight because safer streets and open spaces “allowed them to walk outside more, or because they saw thinner people around them, or both.”

This story provided by ScienceNOW, the daily online news service of the journal Science.

Image: People who were relocated to more affluent areas (left) from poor neighborhoods (right) in Chicago became less obese and healthier. (Fotosearch — left; Sean Parnell — right)

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