Best practices for using natural experiments to evaluate retail food and beverage policies and interventions.

Policy and programmatic change in the food retail setting, including excise taxes on beverages with added-caloric sweeteners, new supermarkets in food deserts, and voluntary corporate pledges, often require the use of natural experimental evaluation for impact evaluation when randomized controlled trials are not possible. Although natural experimental studies in the food retail setting provide important opportunities to test how nonrandomized interventions affect behavioral and health outcomes, researchers face several key challenges to maintaining strong internal and external validity when conducting these studies. Broadly, these challenges include 1) study design and analysis; 2) selection of participants, selection of measures, and obtainment of data; and 3) real-world considerations. This article addresses these challenges and different approaches to meeting them. Case studies are used to illustrate these approaches and to highlight advantages and disadvantages of each approach. If the trade-offs required to address these challenges are carefully considered, thoughtful natural experimental evaluations can minimize bias and provide critical information about the impacts of food retail interventions to a variety of stakeholders, including the affected population, policymakers, and food retailers.

School Breakfast Program Participation and Rural Adolescents' Purchasing Behaviors in Food Stores and Restaurants.

BACKGROUND: Little is known about adolescents' food purchasing behaviors in rural areas. This study examined whether purchasing food at stores/restaurants around schools was related to adolescents' participation in school breakfast programs and overall diet in rural Minnesota. METHODS: Breakfast-skippers enrolled in a group-randomized intervention in 2014 to 2015 (N = 404 from 8 schools) completed 24-hour dietary recalls and pre/post surveys assessing food establishment purchase frequency. Healthy Eating Index Scores (HEI-2010) were calculated for each student. Student-level school breakfast participation (SBP) was obtained from school food service records. Mixed-effects regression models estimated: (1) whether SBP was associated with store/restaurant use at baseline, (2) whether an increase in SBP was associated with a decrease in store/restaurant use, and (3) whether stores/restaurant use was associated with HEI-2010 scores at baseline. RESULTS: Students with increased SBP were more likely to decrease fast-food restaurant purchases on the way home from school (OR 1.017, 95% CI 1.005, 1.029), but were less likely to decrease purchases at food stores for breakfast (OR 0.979, 95% CI 0.959, 0.999). Food establishment use was associated with lower HEI-2010 dairy component scores (p = .017). CONCLUSIONS: Increasing participation in school breakfast may result in modest changes in purchases at food establishments.

Results of a Pilot Intervention in Food Shelves to Improve Healthy Eating and Cooking Skills Among Adults Experiencing Food Insecurity.

Since the start of the 2007 economic downturn, reliance on emergency food assistance suppliers (e.g., food pantries, also known as food shelves) has increased. Many food shelves strive to provide effective nutrition programs to serve their clients, even while they are faced with a scarcity of resources. Rigorous evaluation of the impact of such programming on dietary outcomes is, therefore, warranted. The aim of this study was to evaluate the effectiveness of a pilot cooking and nutrition education intervention among food shelf clients. A six-session class was conducted with 63 participants in four food shelves in Minneapolis and St. Paul, MN. Diet was assessed through a 24-hour recall from which a Healthy Eating Index (HEI) score was created. Cooking skills were assessed by survey. Average HEI scores increased from 50.9 at baseline to 58.5 post-intervention (p = 0.01, n = 43). Participants demonstrated improved cooking skills scores post-intervention (35.9 vs. 33.1 at baseline, p = 0.002, n = 45). Future research is needed to advance our understanding of how best to improve client nutrition knowledge and cooking skills. This study provides some evidence that improvements in diet and skills can be demonstrated with minimal intervention.

Geographic access to food shelves among racial/ethnic minorities and foreign-born residents in the Twin Cities.

Place-based disparities in access to affordable food sources (e.g., supermarkets) have been well documented, but geographic access to emergency food sources (e.g., food panties, also known as food shelves) is unknown. This study examined the geography of emergency food in the Twin Cities, MN. U.S. Census and American Community Survey data were used to estimate the average distance to the closest food shelf according to area racial/ethnic composition and foreign-born group composition. In adjusted models, areas with the highest proportion of minority groups had shorter distances to the nearest food shelf (0.13-1.03 log-transformed miles, p <0.05), as did census tracts with more residents born in East Africa and Latin America (0.29-0.31 log-transformed miles, p< 0.001). Areas with more racial/ethnic minorities and foreign-born groups may have access to emergency food, but efforts are needed to evaluate the healthfulness and culturally relevance of these offerings.

Modified ground-truthing: an accurate and cost-effective food environment validation method for town and rural areas.

BACKGROUND: A major concern in food environment research is the lack of accuracy in commercial business listings of food stores, which are convenient and commonly used. Accuracy concerns may be particularly pronounced in rural areas. Ground-truthing or on-site verification has been deemed the necessary standard to validate business listings, but researchers perceive this process to be costly and time-consuming. This study calculated the accuracy and cost of ground-truthing three town/rural areas in Minnesota, USA (an area of 564 miles, or 908 km), and simulated a modified validation process to increase efficiency without comprising accuracy. For traditional ground-truthing, all streets in the study area were driven, while the route and geographic coordinates of food stores were recorded. RESULTS: The process required 1510 miles (2430 km) of driving and 114 staff hours. The ground-truthed list of stores was compared with commercial business listings, which had an average positive predictive value (PPV) of 0.57 and sensitivity of 0.62 across the three sites. Using observations from the field, a modified process was proposed in which only the streets located within central commercial clusters (the 1/8 mile or 200 m buffer around any cluster of 2 stores) would be validated. Modified ground-truthing would have yielded an estimated PPV of 1.00 and sensitivity of 0.95, and would have resulted in a reduction in approximately 88 % of the mileage costs. CONCLUSIONS: We conclude that ground-truthing is necessary in town/rural settings. The modified ground-truthing process, with excellent accuracy at a fraction of the costs, suggests a new standard and warrants further evaluation.

Differences in healthy food supply and stocking practices between small grocery stores, gas-marts, pharmacies and dollar stores.

OBJECTIVE: Little is known about the practices for stocking and procuring healthy food in non-traditional food retailers (e.g., gas-marts, pharmacies). The present study aimed to: (i) compare availability of healthy food items across small food store types; and (ii) examine owner/manager perceptions and stocking practices for healthy food across store types. DESIGN: Descriptive analyses were conducted among corner/small grocery stores, gas-marts, pharmacies and dollar stores. Data from store inventories were used to examine availability of twelve healthy food types and an overall healthy food supply score. Interviews with managers assessed stocking practices and profitability. SETTING: Small stores in Minneapolis and St. Paul, MN, USA, not participating in the Special Supplemental Nutrition Program for Women, Infants, and Children. SUBJECTS: One hundred and nineteen small food retailers and seventy-one store managers. RESULTS: Availability of specific items varied across store type. Only corner/small grocery stores commonly sold fresh vegetables (63% v. 8% of gas-marts, 0% of dollar stores and 23% of pharmacies). More than half of managers stocking produce relied on cash-and-carry practices to stock fresh fruit (53%) and vegetables (55%), instead of direct store delivery. Most healthy foods were perceived by managers to have at least average profitability. CONCLUSIONS: Interventions to improve healthy food offerings in small stores should consider the diverse environments, stocking practices and supply mechanisms of small stores, particularly non-traditional food retailers. Improvements may require technical support, customer engagement and innovative distribution practices.

Results of a pilot intervention to improve health and safety for health care workers.

OBJECTIVE: To test the feasibility of a multicomponent pilot intervention to improve worker safety and wellness in two Boston hospitals. METHODS: A 3-month intervention was conducted on seven hospital units. Pre- (374 workers) and postsurveys (303 workers) assessed changes in safety/ergonomic behaviors and practices, and social support. Wellness outcomes included self-reported pain/aching in specific body areas (musculoskeletal disorders or MSDs) and physical activity (PA). RESULTS: Pain was reported frequently (81%), and PA averaged 4 hours per week. There was a postintervention increase in safe patient handling (P < 0.0001), safety practices (P = 0.0004), ergonomics (P = 0.009), and supervisor support (P = 0.01), but no changes in MSDs or PA. CONCLUSIONS: Safe patient handling, ergonomics, and safety practices are good targets for worker safety and wellness interventions; longer intervention periods may reduce the risk of MSDs.