Research shows that higher risk is based on availability of food stores
A recent Kansas State University study found that the availability of supermarkets -- rather than the lack of them --increased the risk of obesity for low-income women living in small cities. This suggests that policies to increase healthful eating behaviors might need to be tailored based on geographic location.
K-State researchers studied the availability of food stores for low-income women in Kansas to see whether there was a link to obesity. The findings showed that limited availability of grocery stores did not contribute to an increased risk of obesity in metropolitan or rural areas, but it was associated with an increased risk of obesity in micropolitan areas in Kansas, defined as cities with fewer than 40,000 people.
"This study was one of the first to look at supermarket availability across the urban-rural continuum, and the findings suggest that policies to increase healthful food availability may need to differ depending on urban influence," said David Dzewaltowski, K-State professor and department head of kinesiology.
Dzewaltowski and Paula Ford, assistant professor of public health sciences at the University of Texas at El Paso, published the study in the January issue of Obesity, a research journal. Ford led the project as a doctoral student at K-State.
Research has shown that a lack of nearby food stores that offer healthful items contributes to higher incidences of obesity for consumers. Studies also have shown that low-income residents have an improved quality of diet when larger grocery stores and supermarkets are available. That's because these stores often supply consumers with healthful foods at a lower cost compared to small grocery and convenience stores.
Dzewaltowski said most studies that have investigated links between food environments and obesity have relied upon census tracts or ZIP codes for analysis. However, this can lead to faulty results. The K-State study used a statewide, geographically referenced dataset of Kansans participating in the Special Supplemental Nutrition Program for Women, Infants and Children from October 2004 to December 2006.
"Previous research assumes that most people shop within their own census tract or ZIP code," Ford said. "However, other studies have found that most people shop outside of their census tract. By examining the number of stores within a 1- to 3-mile radius of these women's homes, we were able to get a more accurate and realistic assessment of supermarket availability."
To be eligible for the Special Supplemental Nutrition Program, a recipient must be a pregnant, breastfeeding or postpartum woman with children younger than 5 years old and a household income less than 185 percent of the federally designated poverty level. The researchers' data included each woman's body mass index.
The study included only socioeconomically disadvantaged women because they are at greater risk of obesity than are wealthier women. They also are likely to be more dependent on nearby grocery stores and supermarkets because of limited transportation options and fewer economic resources, Ford said.
The researchers looked at the availability of food stores -- specifically convenience and grocery stores and supermarkets -- located within a radius of 1, 3 or 5 miles of the women's residences. The women's homes also were categorized as being in a rural, micropolitan or metropolitan area. The first item the researchers examined was the availability of these stores in the different areas.