Dr. Amy Auchincloss, an assistant professor in Drexel’s School of Public Health, was the lead author of a study recently published in the journal Obesity, showing that healthy food access in neighborhoods may have helped reduce the incidence of obesity by about 10 percent. You can read more about the study in our press release.
Here are some added comments and discussion points Auchincloss shared about the study and its implications:
On some of the strengths of this study compared to others that have examined similar questions about neighborhoods and health:
Most studies to date in this area have been cross-sectional and/or single-city studies. This study was longitudinal and recruited a diverse sample of participants from six sites around the U.S.
This means that, compared to previous studies, the data we collected could give a more robust understanding of whether the neighborhood environment was really what helps people stay healthy.
On various biases that need to be considered in this type of research:
Selection bias can make it hard to tease out neighborhood effects because people who have the resources to invest in their health and have healthier behaviors, also tend to choose to live in neighborhoods that support a healthy lifestyle. In other words, people who are fortunate enough to choose where they live can choose neighborhoods that match their preferences for healthy eating and physical activity. Sociological and demographic research has found that the ability of persons to self-select neighborhoods depends strongly on income and race/ethnicity — thus, we adjusted for these variables in multivariable regression.
We were also careful to control for perception biases – that people who already walk more, or shop locally for healthy foods, are more likely to perceive their neighborhood as walkable, or as rich in access to healthy foods.
This can be a concern especially when neighborhood information and behaviors are self-reported by the same subjects. We got around this issue by averaging survey reports of the neighborhood but did not include the respondent’s report of their own neighborhood to avoid spurious associations.
On the idea of “walkability” in this study and others like it:
Simply having destinations within walking distance such as stores, cleaners, and faith-based organizations, promotes walking. In this study, we asked people, is it easy to walk places near your home?
On seeking to measure separate effects of healthy food access and walkability on obesity risk:
We analyzed the data for each variable independently – healthy food environment, and walking environment – to see if each had an independent effect on obesity. We found that the healthy food environment did indeed have a statistically significant effect, independent of walkability. But these regression models that included both food and walking environment variables did not consistently detect an association of walkability with obesity independent of the food environment. That is likely in part due to the fact that, in many areas, better food environments also have better walking environments. Also, other things that have negative impacts on health (and obesity in particular) may be co-located with better walking environments.
On choosing a neighborhood for optimal health:
A good rule of thumb is to try to live near a food store with healthy food options, to the extent that it’s possible. If you can find and afford to live in a neighborhood where you can shop for fresh fruits and vegetables more often, near home, you may be more likely to consume those foods more regularly.
Note to news media: If you have additional questions about this study, please email either me (firstname.lastname@example.org) or Auchincloss (email@example.com). Please note that she prefers to receive interview questions via email.
Auchincloss A.H., Mujahid M.S., Shen M., Michos E.D., Whitt-Glover M.C. & Diez Roux A.V. (2013). Neighborhood health-promoting resources and obesity risk (the multi-ethnic study of atherosclerosis), Obesity, 21 (3) 621-628. DOI: 10.1002/oby.20255