Effect of alcohol label designs with different pictorial representations of alcohol content and health warnings on knowledge and understanding of low‐risk drinking guidelines: a randomized controlled trial

Abstract

Background and aims The UK low‐risk drinking guidelines (LRDG) recommend not regularly drinking more than 14 units of alcohol per week. We tested the effect of different pictorial representations of alcohol content, some with a health warning, on knowledge of the LRDG and understanding of how many drinks it equates to. Design Parallel randomized controlled trial. Setting On‐line, 25 January–1 February 2019. Participants Participants (n = 7516) were English, aged over 18 years and drink alcohol. Interventions The control group saw existing industry‐standard labels; six intervention groups saw designs based on: food labels (serving or serving and container), pictographs (servings or containers), pie charts (servings) or risk gradients. A total of 500 participants (~70 per condition) saw a health warning under the design. Measurements Primary outcomes: (i) knowledge: proportion who answered that the LRDG is 14 units; and (ii) understanding: how many servings/containers of beverages one can drink before reaching 14 units (10 questions, average distance from correct answer). Findings In the control group, 21.5% knew the LRDG; proportions were higher in intervention groups (all P < 0.001). The three best‐performing designs had the LRDG in a separate statement, beneath the pictograph container: 51.1% [adjusted odds ratio (aOR) = 3.74, 95% confidence interval (CI) = 3.08–4.54], pictograph serving 48.8% (aOR = 4.11, 95% CI = 3.39–4.99) and pie‐chart serving, 47.5% (aOR = 3.57, 95% CI = 2.93–4.34). Participants underestimated how many servings they could drink: control mean = −4.64, standard deviation (SD) = 3.43; intervention groups were more accurate (all P < 0.001), best performing was pictograph serving (mean = −0.93, SD = 3.43). Participants overestimated how many containers they could drink: control mean = 0.09, SD = 1.02; intervention groups overestimated even more (all P < 0.007), worst‐performing was food label serving (mean = 1.10, SD = 1.27). Participants judged the alcohol content of beers more accurately than wine or spirits. The inclusion of a health warning had no statistically significant effect on any measure. Conclusions Labels with enhanced pictorial representations of alcohol content improved knowledge and understanding of the UK's low‐risk drinking guidelines compared with industry‐standard labels; health warnings did not improve knowledge or understanding of low‐risk drinking guidelines. Designs that improved knowledge most had the low‐risk drinking guidelines in a separate statement located beneath the graphics.

Nature and Potential Impact of Alcohol Health Warning Labels: A Scoping Review

“…In total, we identified 27 papers that fit our inclusion criteria (see Appendix A for PRISMA diagram) [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ]. One paper reported on two studies using different methodologies to study the same variables [ 50 ], and four papers reported on different aspects of one intervention [ 51 , 52 , 53 , 54 ].…”

“…In terms of study aims and studied independent variables, five papers (19%) compared only new or enhanced labels with no or regular labels [ 51 , 52 , 53 , 54 , 63 ]. Focusing on label content, eight papers (30%) compared text-only labels with text and image labels [ 55 , 56 , 61 , 62 , 64 , 65 , 66 , 67 ], twelve studies (44%) compared text message characteristics (e.g., content, specificity, framing, source, use of causal language) [ 57 , 58 , 59 , 60 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 ] and three (11%) compared image characteristics [ 57 , 66 , 75 ].…”

“…In terms of label content, eight studies studied a single message; the remaining were either comparing different labels (or groups of labels) or used several messages as a single intervention. Most commonly, the messages were referring either to cancer in general (e.g., “Warning: Alcohol causes cancer”) [ 51 , 52 , 53 , 54 , 57 , 58 , 59 , 60 , 63 , 67 , 71 , 75 ], or specifically to bowel cancer (e.g., “Alcohol causes bowel cancer”) [ 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 69 , 71 ], both in 41% of all papers. Overall, 70% of papers included at least one cancer-related message, with other mentioned cancers being also breast (33%) [ 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 60 ] and liver cancer (30%) [ 55 , 56 , 57 , 61 , 62 , 64 , 69 , 76 ].…”

“…In terms of label format, the majority of the papers formatted the labels to be clearly visible. This meant putting labels on the front of the pack, with a predetermined size and clear contrast between text and background and separation from the rest of the label (e.g., black text on white background with black or red border, such as [ 55 , 56 , 57 , 61 , 63 ] or black text on a bright yellow background and red border, such as [ 51 , 52 , 53 , 54 ]). A complete description of the studied labels content and format is available in Supplementary Table S1 .…”

“…A large online UK study [ 63 ] did not find that adding a text warning to alcohol drink label changed perceived personal risk, motivation to drink less or perception of damaging drinking among adult drinkers. On the other hand, the Canadian real-world study, which included putting three types of labels (one of them a cancer warning) on the majority of alcohol drinks in the participating liquor stores in the studied region, found that these enhanced labels led to increased recall, cognitive processing and self-reported impact of drinking [ 51 , 54 ], as well as decreased alcohol sales [ 53 ] in the intervention municipality compared to the control municipality.…”