Identifying attributes of effective cigar warnings: a choice-based conjoint experiment in an online survey of US adults who smoke cigars

Objective: Little evidence exists on which cigar warning statement attributes may impact cigar warning effectiveness; research is needed to identify the most effective cigar warning topics and text. This study was designed to inform the development of improved cigar warnings.

Design: We conducted a choice-based conjoint experiment. The experiment systematically manipulated cigar warning statement attributes, including cancer health effect (mention of colon cancer and/or oral cancer), non-cancer health effect (mention of heart disease and/or blood clots), causal language, warning marker word, verb use and tobacco type. Participants evaluated eight choice sets, each containing three cigar warnings with contrasting attributes, and chose the warnings that most and least encouraged them to quit smoking cigars. Using a Bayesian mixed logit model, we estimated the relative importance of each attribute and the attribute part-worth utility.

Setting: An online survey of adults in the USA.

Participants: We enrolled 959 US adults who used little cigars, cigarillos, or large cigars in the past 30 days using an online survey from October to December 2020.

Primary outcome measures: The primary outcomes for the experiment are relative attribute importance and attribute part-worth utility.

Results: The most important attributes to participant selection of warnings were the non-cancer and the cancer health effects (29.3%; 95%CI 28.6% to 30.0% and 29.0%; 95% CI 28.4% to 29.6%, respectively), followed by causal language (16.3%; 95% CI 15.7% to 16.8%), marker word (10.3%; 95% CI 9.9% to 10.7%), verb use (8.8%; 95% CI 8.5% to 9.2%) and tobacco type (6.3%, 95% CI 5.9% to 6.6%).

Conclusions: Our findings indicate that health effects are the most important attributes when designing cigar warning statements, but other attributes, like causal terminology, also influence perceived warning effectiveness. Based on our findings, 'DANGER: Tobacco causes heart disease and blood clots' is an example of a highly effective warning statement for cigars.