Food swamps are areas with a higher density of fast food and junk food options. A new study suggests that living near such areas increases stroke risk among those ages 50 and older.
More than ten years ago, the term “food swamp” was created to describe neighborhoods where fast-food restaurants and convenience stores are prevalent, swamping the areas with unhealthy food options. Food swamps frequently coexist with food deserts, where a lack of grocery stores makes it harder to get fresh produce and nutritious food.
Food swamps and the potential link to stroke need to be better studied. In a new study, scientists analyzed whether food swamp environments might be associated with greater odds of stroke.
For this study, they reviewed data from the Health and Retirement Study (H.R.S.), an ongoing study conducted at the University of Michigan that recruits participants throughout the U.S. to study the challenges and opportunities associated with aging and retirement. The U.S. Department of Agriculture’s food environment data was then cross-referenced with this information to create the retail food environment index (RFEI), which measures the proportion of fast-food outlets and convenience stores to the availability of healthy food options in a given neighborhood.
This study used secondary analysis to examine information gathered between 2010 and 2016. Scientists applied an enhanced retail food environment score based on participant health data. The retail food environment index classed grocery stores, farmer’s markets, and specialty food stores as healthy food retailers. In contrast, convenience stores, fast food chains, and full-service restaurants were categorized as unhealthy food options.
With statistical weighting applied to approximate the general U.S. population, the study included 17,875 individuals with an average age of 64, 54% women and 84% white people. Each person was weighted based on survey design/sampling to represent a much larger U.S. population of more than 84 million community-dwelling, stroke-free adults. Two categories were established for the retail food environment index: a ratio of 5 or greater or less than 5.
Dixon Yang, M.D., lead author of the study and a postdoctoral fellow at Columbia University Irving Medical Center in New York City, said, “The two categories were chosen for comparison because prior research has shown that a retail food environment index ratio of 5 or higher may predict the prevalence of people with obesity in a neighborhood.”
The analysis found that: more than 3 million people, or 3.8% of those studied, self-reported as having had a stroke:
The percentage of people living in areas with a retail food environment index below 5 was 28%, and those living in areas ranked as five or higher on the food environment index was 72%.
People in the higher retail food environment index group (ratio five or more) had 13% higher odds of incident stroke than those who lived in neighborhoods with an index score below 5.
Yang said, “The overall median retail food environment index across all communities was a ratio of 6. It means many participants lived in an area with 6 times the amount of unhealthy to healthy food retailers.”
“Our research highlights the potential importance of an area’s retail food options as a structural factor affecting stroke, especially since most participants resided in areas with six times the amount of relative unhealthy to healthy food choices.”
Because the study’s cross-sectional methodology only included data from a single point in time, it was impossible to establish a causal relationship between the retail food environment score and stroke. Additionally, there was no information on the type of stroke, and strokes were self-reported.
Yang said, “At this early stage of our research, it’s important to raise awareness that a person’s neighborhood and food environment are potentially important factors affecting their health, especially among people who may have difficulty reaching optimal cardiovascular health targets. In the future, it may help to focus on community-based interventions or dietary guidance to improve cardiovascular health, hopefully reducing the risk of stroke.”
Anne N. Thorndike, M.D., M.P.H., FAHA, immediate past chair of the American Heart Association’s Nutrition Committee, said, “In this study of older, community-dwelling, adults in the U.S., the majority of the people lived in areas with a high-density of unhealthy food options. The association between having a stroke and living in an unhealthy food environment highlights the importance of having effective policies and programs that can help to improve access to healthier food options for all Americans.”
The team is presenting their research at the American Stroke Association’s International Stroke Conference 2023.