Real-world exposure to graphic warning labels on cigarette packages in US smokers: The CASA randomized trial protocol

BACKGROUND: The US lags behind >120 countries in implementing graphic warning labels (GWLs) on cigarette packs. US courts prevented implementation of FDA's 2012 rule requiring GWLs citing the need for more evidence on effectiveness. After more research, in 2020, the FDA proposed a revised rule mandating GWLs. This trial will test how the introduction of GWLs influence cognitions and behavior in US smokers. METHOD: To investigate the “real-world” impact of GWLs in US smokers, we are conducting a randomized trial involving a 3-month intervention and 8-month follow-up. The study recruited California smokers between September 2016 through December 2019 and randomly assigned them into 3 groups (1) Blank Pack devoid of any cigarette branding; (2) GWL Pack featuring 1 of 3 rotating images added to blank pack; or (3) their usual Standard US Pack. Throughout the 3-month intervention, participants purchased study-packaged cigarettes and reported daily cognitions and behavior through ecological momentary assessments. We will validate self-reported tobacco use with saliva cotinine concentrations following the 3-month intervention and 8-month follow-up. RESULTS: The trial enrolled 359 participants (average age 39 years; average cigarette consumption half a pack/day). The 3 study groups were balanced on age, gender, race-ethnicity, education and income (17% low income) as well as on smoking related variables. CONCLUSIONS: This 3-month real-world randomized trial will test the effect of repackaging cigarettes from standard US packs to GWL plain packs on smokers' perceptions of the risks of smoking, their perception of the appeal of their cigarettes, and on their smoking behavior.