The closer African Americans live to fast food restaurants the greater their odds of having high BMI, or body mass index, a measure of obesity.

Researchers from University of Texas MD Anderson Cancer Center have studying this trend. In a recently-released report, they found that black adults living in a closer proximity to fast food restaurants had a higher BMI than those living farther away. For every mile participants lived from the closest fast food restaurant was correlated with a 2.4 percent lower BMI.

“Environment does affect health outcomes, mortality and other behaviors, and this study is one example of that,” said lead study author, Lorraine Reitzel, assistant professor in the Department of Health and Disparities research at MD Anderson.

The study appears in the current edition of the American Journal of Public Health.

The study gathered data from 1,400 black adults from Project CHURCH, an acronym for Creating a Higher Understanding of Cancer Research and Community Health. The research initially was conducted to better understand the different factors related to cancer risks among black adults.

“African Americans are at a higher risk of obesity which is linked to an increase in cancer, diabetes and heart disease,” Reitzel said.

There is also a behavioral economics element to the findings, Reitzel added.

“In general, people engage in behaviors that are most convenient. If fast food is closer to you, it reduces the cost in time, money and effort,” she said.

In the study, fast food restaurant density was only positively associated with BMI among participants with incomes less than $40,000 a year. By contrast, proximity was associated with higher BMI among all participants, although there was a stronger correlation among those with lower incomes.

These findings readily translate to Chicago, according to Lisa Powell, associate director of the Health and Policy Center at the University of Illinois at Chicago.

“The results make sense for a number of reasons. Transportation costs would be more of a barrier than food costs and proximity. These variables are most likely generalizable in other major cities like Chicago,” she said.

Closer proximity reduces the cost of using fast food outlets for low-income individuals.

“If fast food is closer to you, it reduces the cost in time and effort to obtain food. Whereas if it’s farther it takes more time and effort and thought. So, the accessibility factor is a prime indicator, Reitzel said, adding that study is unique in that it focuses on the relationship between fast food restaurants and its effect on the black community.

The findings, according to Reitzel, are not limited to one race in particular.

“This issue,” she said, “is not specific to African Americans but they are a population at a higher risk for a number of health disparities. We have to study things within groups that present higher risks to better understand if there are predisposed factors.”

It is also known that there is a higher density of fast food restaurants in areas with large minority populations, and in areas populated by lower-income residents.

Researchers note that these communities have fewer healthy options available. The restaurants in these neighborhoods also offer unhealthy food options to residents.

“I think these relationships may operate the same in different racial groups,” Reiztel said, “but there are studies that indicate there may be more restaurants in low income and minority neighborhoods.”