It’s well established that environment can influence a person’s weight as much as their genes or their behavior. For people growing up in inner city environments where fast food restaurants and liquor stores far outnumber grocery stores with fresh food options, it’s a struggle to piece together healthy meals on a consistent basis. But beyond “food deserts,” can a person’s neighborhood also influence their weight and their health in more subtle ways? Could less tangible factors such as crime rates and community networks contribute to the health disparities of race and socioeconomic status?
University of Chicago researcher Kathleen Cagney and Christopher Browning of Ohio State University set out to answer those intriguing questions by merging enormous data sets of health information and crime rates. The results of that study, presented by Cagney on October 6 at the MacLean Center Seminar Series, suggested that a person’s social surroundings – and the local police blotter – can exert a great influence on their health and fitness.
Cagney and Browning started with the Dallas Heart Study, a survey of thousands of residents of the Texas city on parameters relevant to cardiovascular heath. Focusing on one measure – body mass index, or BMI – the researchers then plotted the data against changes in local crime rate from police data for each patient, focusing in particular on short-term “crime spikes.” The hypothesis was that an increase in crime nearby the person’s home could produce stress and discourage outdoor activity, leading to less exercise, increased consumption of unhealthy “comfort food,” and activation of the hormonal “fight-or-flight” response.
“If something changes dramatically in your environment or in your community, you can imagine that your life behaviors and patterns would change in concert with that,” Cagney said.
After controlling for several other factors (a necessity for so broad a research question), Cagney said a significant effect of crime spikes on BMI was found for one group: women. Females from neighborhoods that had experienced the largest increase in crime over the past six months experienced a rise in BMI, equivalent to roughly a 2.7-pound weight gain for a typical 130-pound person. The weight of men in the study was found to be slightly sensitive to the overall crime rate in their neighborhood, but not the short-term dynamics of crime spikes, Cagney said.
Another level of neighborhood factors was also examined in the study, as Cagney and Browning examined whether the principle of “social cohesion” modified the effect of crime on waistlines. Defined by Cagney as “about the ability of a community to come together for the common good,” the measure might be predicted to decrease the effect of crime through a unified neighborhood response. However, they found that higher social cohesion actually increased the effect of crime spikes on female subject’s BMI, suggesting that a strong social network may actually magnify the stressful effects of local criminal activity.
“In communities with high levels of social cohesion, people seem to gain weight more rapidly,” Cagney said. “It’s not what’s happening, it’s what you think is happening, because it’s perceptions that shape behavior.”
One example of this phenomenon may have introduced a strong confound into the Dallas Heart Study data, and by extension, Cagney and Browning’s study. The Dallas data was collected from 2000-2003, and right in the middle of that stretch was a whopper of an environmental stressor: the terrorist attacks of 9/11. Thinking that they saw an artifact of that event in the data, even over a thousand miles from New York City and Washington, DC, Cagney and Browning plotted the BMI changes in subjects measured before 9/11 against those measured across 9/11 – and found almost twice the weight gain in the latter group. Even when a person’s neighborhood temporarily expands to include the entire country, crime can seemingly translate into a few extra pounds.
[Each academic year, the MacLean Center for Clinical Medical Ethics organizes a series of lunchtime seminars by physicians, biologists, economists, social scientists and other experts covering the biggest questions in health care and ethics. This year’s theme is “Health Disparities: Local, National, Global,” and the series was put together with the Urban Health Initiative, the Global Health Initiative, and Finding Answers. ScienceLife will carry regular coverage of this unique series, often accompanied by video of the lectures provided by the MacLean Center.]