The impact of pictorial health warnings on purchases of sugary drinks for children: A randomized controlled trial

Abstract

Background Pictorial warnings on tobacco products are promising for motivating behavior change, but few studies have examined pictorial warnings for sugary drinks, especially in naturalistic environments. This study aimed to examine the impact of pictorial warnings on parents’ purchases of sugary drinks for their children in a naturalistic store laboratory. Methods and findings Parents of children ages 2 to 12 (n = 325, 25% identifying as Black, 20% Hispanic) completed a shopping task in a naturalistic store laboratory in North Carolina. Participants were randomly assigned to a pictorial warnings arm (sugary drinks displayed pictorial health warnings about type 2 diabetes and heart damage) or a control arm (sugary drinks displayed a barcode label). Parents selected 1 beverage and 1 snack for their child, as well as 1 household good; one of these items was selected for them to purchase and take home. The primary outcome was whether parents purchased a sugary drink for their child. Secondary outcomes included reactions to the trial labels, attitudes toward sugary drinks, and intentions to serve their child sugary drinks. Pictorial warnings led to a 17-percentage point reduction in purchases of sugary drinks (95% CI for reduction: 7% to 27%), with 45% of parents in the control arm buying a sugary drink for their child compared to 28% in the pictorial warning arm (p = 0.002). The impact of pictorial warnings on purchases did not differ by any of the 13 participant characteristics examined (e.g., race/ethnicity, income, education, and age of child). Pictorial warnings also led to lower calories (kcal), purchased from sugary drinks (82 kcal in the control arm versus 52 kcal in the pictorial warnings arm, p = 0.003). Moreover, pictorial warnings led to lower intentions to serve sugary drinks to their child, feeling more in control of healthy eating decisions, greater thinking about the harms of sugary drinks, stronger negative emotional reactions, greater anticipated social interactions, lower perceived healthfulness of sugary drinks for their child, and greater injunctive norms to limit sugary drinks for their child (all p 0.05). Conclusions Pictorial warnings reduced parents’ purchases of sugary drinks for their children in this naturalistic trial. Warnings on sugary drinks are a promising policy approach to reduce sugary drink purchasing in the US. Trial registration The trial design, measures, power calculation, and analytic plan were registered before data collection at www.clinicaltrials.govNCT04223687. Using a naturalistic store laboratory, Marissa Hall and colleagues examine the impact of pictorial warnings on parents’ purchases of sugary drinks for their children. Author summary Why was this study done? Children in the US consume more than the recommended levels of sugary drinks, increasing their risk of a variety of chronic diseases, including type 2 diabetes and heart disease. Experimental studies of text-only sugary drink warning labels indicate that warnings reduce sugary drink consumption. To our knowledge, studies have not yet examined the effects of pictorial warnings on parents’ purchases of sugary drinks for their children or on purchases in naturalistic settings. What did the researchers do and find? Parents of children aged 2 to 12 years (n = 325) participated in a randomized trial. Participants were randomized to a pictorial warnings arm (sugary drinks displayed pictorial health warnings about type 2 diabetes and heart damage) or a control arm (sugary drinks displayed a barcode label). Participants completed a shopping task in a naturalistic store laboratory, where sugary drinks had the assigned label, and completed a survey. Exposure to pictorial warning labels on sugary drinks led to a 17% absolute reduction in the purchasing of sugary drinks compared to exposure to the barcode control label. What do these findings mean? Pictorial warnings are a promising option for reducing purchases of sugary drinks for children. Implementation of pictorial warning label policies could be an effective strategy for reducing sugary drink purchases and sugary drink–related health outcomes. Future studies should evaluate the long-term effects of warning labels on children’s sugary drink consumption and prevalence of diet-related chronic disease.