The impact of varying warning color on e-cigarette advertisements: Results from an online experiment among young adults.

INTRODUCTION Advertisement warnings are often overlooked, which reduces the opportunity for risk communication. METHODS We used Prolific to survey 1,131 young adults (18-35) who currently used e-cigarettes or tobacco products. We randomized participants to one of four warning conditions: black text on white background (BW), white on black (WB), black on yellow (BY), and yellow on black (YB). We examined associations between condition and attention, recall, ad appeal, perceived message effectiveness (PME), and intentions to use e-cigarettes using chi-square and ANOVA where appropriate. We conducted logistic regressions by condition for attention and recall controlling for demographics and tobacco use. RESULTS The warning was selected as the most attention-capturing area of the advertisement more often by those exposed to yellow warnings than white (59.9% versus 46.8%), even after controlling for demographics and tobacco use (p<.05). Recall was greater among those exposed to yellow warnings than white (44.2% vs. 37.3%), which held in controlled models. There were no significant differences between yellow and white warnings for ad appeals, PME, or intentions to use. In subanalyses, WB warnings generated higher PME (10.1 vs. 9.5) and lower intentions to use e-cigarettes (3.0 vs. 3.3) than BW (each p<.05). CONCLUSIONS Yellow warning color increases attention and recall of the warning, but this increase in attention did not translate to differences in downstream effects. Among currently mandated warning variations, the white text on black background warning appears more effective than the black on white. Future research should examine whether differences translate to behavior change. IMPLICATIONS We tested color variations of the FDA-mandated nicotine text warning on e-cigarette advertisements. Yellow variations (yellow text on black background and black on yellow) better captured attention and increased warning recall compared to the mandated black and white warnings. Among the FDA-mandated black on white and white on black warnings, the white on black variation appears more effective, generating higher perceived message effectiveness and lower intentions to use e-cigarettes. Given the difficulty in implementing pictorial warnings in the US, color might represent an alternative to improve warning effectiveness. Findings may also be applicable to those designing tobacco-related health communications.