Study shows proximity to convenience stores affects children's weight

Thursday, December 10, 2020

It’s no coincidence that fish and chips is a staple meal in pubs across the U.K., a nation of islands surrounded by water. The same is true regarding the prevalence of rice-based dishes in China, the world’s leading producer of the versatile grain.

For better or worse, our environments shape every aspect of our lives, including the food we eat.

In a paper published Dec. 10 in the Journal of the Academy of Nutrition and Dietetics and discussed in a recent episode of the journal's podcast, researchers from Arizona State University and Rutgers University found that children who live in an environment with a higher prevalence of unhealthy food sources, such as convenience stores, are more likely to gain weight over time.

In the study that informed the paper, two groups of children, aged 3 to 15 years old, living in four low-income New Jersey cities – Camden, New Brunswick, Newark and Trenton – were followed over two- to five-year periods from 2009 through 2017. Their weight was recorded once at the beginning of the study and once at the end, then compared to data on availability of food outlets surrounding the children’s homes that had been collected at multiple times throughout the duration of the study.

An increased BMI was observed in children with greater exposure to convenience stores over time, while a lower BMI was observed in children with increased exposure to small grocery stores selling an array of healthy items.

“We've all seen headlines about this, studies saying that bringing supermarkets into low income neighborhoods helps, or studies saying that convenience stores are bad, but we don't have enough longitudinal data to really draw a definitive conclusion about what is going on,” said Punam Ohri-Vachaspati, lead author of the paper and professor of nutrition at ASU’s College of Health Solutions.

The study is a continuation of research she began conducting as a researcher at Rutgers University, and the four cities where children were observed were known to be initiating policy and environmental changes aimed at childhood obesity prevention. Ohri-Vachaspati co-led the study with Michael Yedidia, a professor at the Center for State Health Policy at Rutgers.

“In our study,” Yedidia pointed out, “we had the opportunity to observe the children over time and look at a comprehensive set of food outlets surrounding their homes.”

Researchers on Ohri-Vachaspati’s team, many of whom were ASU undergraduate and graduate students, analyzed thousands of food outlets in the four study cities and each year grouped them as healthy or unhealthy sources of food based on what type of products — for example, fresh vegetables versus nonperishable items — they sold.

Outlets were put into categories including supermarkets, small grocery stores, convenience stores, pharmacies, full-service restaurants or limited service restaurants. Stores were classified as small grocery stores if they sold a specific selection of healthy items, such as five different types of fruits, five different types of vegetables, lower fat milk and fresh or frozen meat. Convenience stores participating in “healthy corner store” initiatives were classified as upgraded convenience stores. 

Changes in children’s food environment included store openings and closings, family moves from one neighborhood to another and upgrades to existing food stores, fostered by community initiatives to improve offerings at convenience stores.

“The data for these kinds of studies needs to be specific to the community you’re observing,” Ohri-Vachaspati said. “One mile around my home in Phoenix is very different than one mile around a child's home in Newark. If you look at some of our data, you'll see that over 80% of the children living in our study cities have a convenience store within a quarter mile of their home.”

Researchers found that when children’s exposure to convenience stores increased over time, so too did unhealthy changes in their BMI. For example, exposure to an additional convenience store within a mile of a child’s home over 24 months resulted in 11.7% greater likelihood of a child being in a higher BMI range compared to other children of the same sex and age. Whereas children who were exposed to an additional small grocery store within a mile over 24 months saw a 37.3% less chance of being in a higher BMI category.

And while Ohri-Vachaspati acknowledges that BMI is not the best indicator for individual health, she maintains it is the best measure we have for population health. As such, she and her team suggest that an increase in the availability of small grocery stores near children’s homes may improve children’s weight status, whereas increased availability of convenience stores is likely to be detrimental.

“If we see that food environment has an impact on children's health, we can design policies to mitigate the negative impacts,” she said. 

Going forward, Ohri-Vachaspati and Yedidia have just received funding to examine what, if any, effects COVID-19 pandemic-related school closures have had on children’s weight status. 

Top image courtesy of Pixabay