The impacts of including information about the number of carcinogens in smoke on standardized cigarette packs in the UK

Background: Since May 2017, standardised packaging has been mandatory in the UK, with packs required to display an ‘information message’ explaining that there are more than 70 carcinogens in tobacco smoke. Methods: Three waves of a longitudinal online survey in the UK with smokers pre-standardised packaging (Wave 1: April-May 2016) and followed up post-standardised packaging (Wave 2: September-November 2017, Wave 3: May-July 2019). Of the 6233 smokers at Wave 1, 4293 responded at Wave 2 and 3175 at Wave 3. We explored knowledge of the number of carcinogens in smoke, and whether knowing that smoke contains more than 70 carcinogens mediated change in the belief that the dangers of smoking are exaggerated (risk perception), stubbing out cigarettes, quit intentions, and quitting. As the information message is larger on roll-your-own packs than on cigarette packs, as the packs are larger, we also explored whether there was any difference in knowing that smoke contains more than 70 carcinogens between exclusive cigarette smokers and exclusive roll-your-own smokers. Results: Knowledge that there are over 70 carcinogens in smoke increased among smokers across waves, with the increase from Waves 1 to 3 greater for exclusive roll-your-own smokers than exclusive cigarette smokers (adjusted Odds Ratio=1.44; 95% CI 1.03-2.03). Knowledge that there are over 70 carcinogens in smoke mediated higher risk perception but not stubbing cigarettes out, quit intentions or quitting. Conclusions: The information message improved knowledge of how many carcinogens are in smoke, particularly among exclusive roll-your-own smokers, and this was linked to higher risk perception