Capturing the healthfulness of the in-store environments of United Kingdom supermarket stores over 5 months (January–May 2019)

Introduction: Numerous environmental factors within supermarkets can influence the healthfulness of food purchases. This research aims to identify the changes in store healthfulness scores and assess the variations by store type and neighborhood deprivation using an adapted Consumer Nutrition Environment tool. Methods: Between January and May 2019, a total of 104 supermarkets in London were surveyed on 1–3 occasions. The adapted Consumer Nutrition Environment tool included data on 9 variables (variety, price, quality, promotions, shelf placement, store placement, nutrition information, healthier alternatives, and single fruit sale) for 11 healthy and 5 less healthy food items. An algorithm was used to create a composite score of in-store healthfulness and to assess inter-rater reliability. Longitudinal changes in overall store healthfulness and individual variables were investigated using multivariable hierarchical mixed models. Descriptive statistics were used to describe the differences by store type and neighborhood deprivation in each month. All analyses were conducted between January and July 2020. Results: The adapted Consumer Nutrition Environment tool showed acceptable inter-rater reliability. Large stores exhibited healthier environments than small stores (p<0.001), with a similar pattern for each of the 9 individual variables. Within large stores, the overall healthfulness score did not change over the study period. Promotions on more healthful items increased in February (p=0.04), and the availability of healthier alternatives for less healthy foods decreased in March (p=0.01). Within small stores, there was a trend toward increasing healthfulness (p<0.001), primarily owing to more promotions on healthy items (p<0.001). There was no difference in overall healthfulness by neighborhood deprivation. Conclusions: The adapted Consumer Nutrition Environment tool is sensitive to longitudinal changes in environmental variables that contribute to store healthfulness. A wider application of this tool could be used to map in-store environments to identify targets for interventions to encourage healthier food purchasing.