A novel tool could help elucidate consumer behaviors at the county level as well as the relationship between the location where individuals shopped for their food and their risk of obesity-related cancer mortality, according to a recent study published by Lin et al in BMC Medicine.
Background
Over 40% and 70% of U.S. individuals currently have obesity and overweight, respectively. A common policy intervention—increasing the number of local grocery stores offering healthy options—has sought to address the prevalence of obesity. However, the initiative has not been as effective as intended.
“Obesity is closely related to cancer, and every year, 5% of the new cancer cases [among male patients and] 10% of cancer cases [among female patients] can be attributed to excessive obesity or body weight—so, it is a very serious problem,” stressed senior study author Ran Xu, PhD, Assistant Professor in the Department of Allied Health Sciences at the University of Connecticut. “From a public policy perspective, intuitively, you think that if you open healthy grocery stores, that will improve [individuals’] diet quality and then reduce obesity,” he added.
Nonetheless previous studies have shown that more factors are involved in the reduction of obesity-related cancers than increasing access to food retailers selling healthy groceries.
Study Methods and Results
Investigators used 2018 to 2019 nation-level, large-scale GPS-tracked mobility data from SafeGraph to analyze where individuals shopped for their food, and retailer location data from InfoGroup that indicated the availability of healthy food options within each neighborhood for about 359,000 retailers across the United States. The investigators designated healthy food locations as grocery stores, large warehouse clubs, and farmers’ markets; and unhealthy food sources as convenience stores and fast-food establishments. They then compared the data with obesity-related cancer mortality data from the U.S. Centers for Disease Control and Prevention from 2015 to 2020 to determine whether the location in which individuals shopped for their food impacted their health outcomes.
“We found that [individuals] go to food retailers that are mostly outside their immediate neighborhoods. Also, in our previous research we found that by tracking where [individuals] go, we can link that with a series of cardiac metabolic diseases like obesity, hypertension, high blood pressure, and diabetes,” Dr. Xu revealed. “We found the strongest association with obesity. In this paper, we go deeper into that and try to see if there is a link between [individuals’] food retailer visit pattern and obesity-related cancer mortality,” he explained.
The investigators used the data to develop an activity-based index of the percentage of visits to healthy food retailers made by individuals from each county. The location-based index was calculated based on the percentage of healthy food retailers located in each county.
“[W]e found that tracking [individual’s] activity and where they go is a much stronger predictor than location for obesity-related cancer mortality events,” Dr. Xu emphasized.
The activity-based index was capable of predicting the obesity-related cancer risk twice as effectively as the traditional location-based approach—representing the need for more research capturing the complexities of human behavior to effectively address the prevalence of obesity. In addition, the association differed by sociodemographic characteristics; for instance, the association was stronger in Hispanic communities. The investigators noted that Hispanic populations tend to have better health outcomes and healthier behaviors compared with other populations despite their more disadvantaged risk factor profile.
“We also found that this association is strong in residents with higher socioeconomic status, and we think that is probably because … they have the financial means to purchase something healthy,” detailed co–study author Peter Chen, PhD, Associate Professor in the Department of Geography, Sustainability, Community, and Urban Studies at the University of Connecticut.
Conclusions
The investigators are leveraging digital tools such as GPS data to better understand the nuance of these problems and the seemingly conflicting results of current policy interventions.
“If you think about food deserts, which are low-income areas without grocery stores, … the government will put resources [there], for example, opening new grocery stores,” stated Dr. Xu. “However, based on our data, because most of the food retailer visits are outside their own neighborhood, we have to wonder, is this really the right approach? We need to focus on the actual behavior and activity, and that might give us better policy outcomes?”
The novel index may be a crucial step in improving the burden of obesity-related cancers. The investigators are currently using GPS data to systematically evaluate the effect of opening new food retailers in food deserts. They plan to explore behaviors and individuals’ purchasing decisions and to complement their findings with qualitative research methods such as surveys to evaluate the dynamic and multidimensional factors influencing why individuals aren’t shopping at healthy grocery stores that may be within their neighborhoods.
Disclosure: For full disclosures of the study authors, visit bmcmedicine.biomedcentral.com.
