Customer-level factors associated with discretionary food and beverage purchasing in Aboriginal and Torres Strait Islander community stores in remote Australia: a customer intercept survey of Healthy Stores 2020

Abstract Background Healthy Stores 2020 (HS2020), a 12-week randomised controlled trial conducted in partnership with an Aboriginal-owned retail organisation, reduced retailer merchandising and store-level purchases of unhealthy foods. Evidence on the influence of customer-level factors (e.g., sociodemographic and shopping behaviour) on unhealthy food purchases in remote Aboriginal and Torres Strait Islander communities is limited. Aims This study of secondary outcomes from HS2020 aimed to determine: (1) Customer-level factors associated with no discretionary, and no free sugar purchases within a food shop; and (2) whether these factors modified response to the HS2020 strategy. Methods A customer intercept survey with collection of transaction data was conducted in the 20 HS2020 participating stores (10 HS2020 strategy; 10 control). Number of items purchased and dollars spent on discretionary and free sugar products was obtained by linking receipt data to a food composition database. Outcomes were discretionary and free sugar purchases per transaction. Robust Poisson regression models estimated associations between outcomes, treatment group, and customer-level factors, with interaction terms to assess effect modification. Statistical significance was set at p < 0.01. Results The analysis included 783 participants – 87.4% Aboriginal and/or Torres Strait Islander. Participants aged ≥ 35 vs. < 35 years had a significantly higher likelihood of no discretionary purchases (RR = 1.52, 95%CI [1.19, 1.95]) and no free sugar purchases (RR = 1.36, 95%CI [1.36, 2.26]). Participants who had low vs. high impulsive shopping behaviours had a higher likelihood of no discretionary purchasing (did not buy extras: RR = 1.46, 95%CI [1.18,1.80]), and no free sugars purchasing (did not buy extras: RR = 1.70, 95%CI [1.27, 2.29]; made up their minds quickly: RR = 1.51, 95%CI [1.11, 2.05]). Shopping in HS2020 strategy stores was suggestive of a higher likelihood of no free sugar purchases, and shopping without children was suggestive of higher likelihood of no discretionary purchases. Conclusions In remote community stores, age ≥ 35 years and some low impulsivity behaviours were protective factors of discretionary purchases. Shopping in HS2020 strategy stores and without children may also be protective factors. Results should be considered in a real-world study context where patterns observed align with existing evidence to support health-enabling in-store initiatives. Trial registration Australian New Zealand Clinical Trials Registry, ACTRN12618001588280.