Does the prevalence of promotions on foods and beverages vary by product healthiness? A population-based study of household food and drink purchases in New Zealand
Abstract Objective: To assess the prevalence of promotions on foods and non-alcoholic drinks purchased by New Zealand households and to determine if they vary according to healthiness of products. Design: We undertook a cross-sectional analysis of Nielsen New Zealand Homescan® 2018/19 panel data. We conducted multivariate analyses to examine the variability in quantities of healthy vs. unhealthy food and beverage products purchased on promotion. Promotion was self-reported by the panelist. Healthiness of products was measured by the Health Star Rating system (HSR). We also carried out a subgroup analysis for beverages according to the threshold of < 5 g vs. ≥ 5 g sugar per 100 ml content of products. Setting: The Nielsen New Zealand Homescan® data were linked with two New Zealand food composition databases (Nutritrack and the FOODfiles). Participants: Food and beverage purchases data by 1,800 panel households were used. Results: Overall, 46% (1,803,601/3,940,458) of all purchases made were on promotion. Compared with purchases of food and beverage products with HSR < 3.5 (unhealthy), food and beverage products with HSR ≥ 3.5 (healthy) were significantly less likely to be on promotion (OR=0.78, 95% CI 0.77 - 0.79). The subgroup analysis for beverages shows that products with < 5 g per 100ml were significantly less likely to be on promotion than those with > 5 g sugar per 100ml (OR=0.76, 95% CI 0.75 - 0.78). Conclusions: Policies to improve healthy food retailing should focus on increasing the promotion of healthier food and drink options in stores and supermarkets.