Obesity and obesity-related cancers are significant public health issues in the United States, contributing to increasing healthcare costs and decreasing life expectancy. Addressing these issues requires improving diet quality, but the link between access to healthy food and cancer outcomes has yielded mixed findings in existing research. While much of the focus has been on the availability of healthy food based on geographic location, food procurement activities—the actual visits to food retailers—have largely been overlooked. This study aims to construct a novel food environment index based on food retailer visits and examine its relationship with obesity-related cancer mortality rates in the US.
Methods: Developing the Activity-Based and Location-Based Food Environment Indices
The study utilized a cross-sectional ecologic approach, incorporating data from 2018–2019 business locations, aggregated GPS-based food retailer visits from SafeGraph, and 2015–2020 mortality data from the Centers for Disease Control and Prevention (CDC). The data covered 2,925 counties or equivalents across the United States.
Two food environment indices were constructed:
Activity-Based Index: This index was calculated by determining the percentage of visits to healthy food retailers out of the total visits to all qualifying food retailers in each county. This measure reflects residents’ actual food purchasing behavior.
Location-Based Index: This index was determined by calculating the percentage of healthy food retailers out of the total number of qualifying food retailers in each county. It represents the availability of healthy food options based on location.
The study focused on age-adjusted obesity-related cancer mortality rates, encompassing 13 types of cancer recognized by the International Agency for Research on Cancer. Counties were categorized into high- and low-risk areas based on cancer mortality rates (≥ 60.2 and < 60.2 cases per 100,000 population).
Multiple regression analyses, including linear, non-linear, logistic, and spatial models, were performed to assess the association between each food environment index and obesity-related cancer mortality rates.
Results: Activity-Based Index Shows Significant Negative Association
The results showed a significant negative association between the activity-based index and obesity-related cancer mortality rates. Specifically, for the 2015–2020 period, each standard deviation increase in the activity-based index was associated with an 18% decrease in the odds of a county being in the high-risk category for obesity-related cancer mortality (odds ratio: 0.821, P < 0.001). The coefficient for the activity-based index was −0.980 (95% CI: −1.385, −0.575, P < 0.001), indicating that counties with higher percentages of visits to healthy food retailers had lower obesity-related cancer mortality rates.
On the other hand, the location-based index showed much weaker and non-significant associations with obesity-related cancer mortality rates. This suggests that while the availability of healthy food options based on location might be important, the actual behavior of residents—reflected in the activity-based index—has a stronger and more direct impact on health outcomes.
Conclusions
The study highlights the importance of incorporating food retailer visits into health policies aimed at combating obesity and obesity-related cancers. The findings suggest that promoting visits to healthy food retailers, rather than merely focusing on the location-based availability of these retailers, may have a more substantial impact on reducing obesity-related cancer mortality.
Key Takeaways:
Activity-Based Index is More Effective: Actual visits to healthy food retailers are more strongly associated with lower obesity-related cancer mortality than the mere presence of healthy food retailers in a community.
Policy Implications: Health policies should consider strategies that encourage residents to visit healthier food retailers, possibly through initiatives like subsidies, transportation support, or education campaigns.
This study offers valuable insights into how food procurement activities, such as visits to healthy food retailers, could play a crucial role in reducing obesity-related cancer rates and improving public health in the United States.
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