Independent and combined effects of very low nicotine cigarette messages and e-cigarette messages: a randomised clinical trial.

BACKGROUND: USA is considering reducing nicotine in cigarettes to non-addictive levels, coupled with promoting alternative nicotine delivery products (eg, e-cigarettes). However, effective communication is needed to reduce misperceptions about very low nicotine cigarettes (VLNCs) being less harmful than regular cigarettes.

METHODS: In 2022-2023, we conducted a four-group randomised clinical trial with a national probability sample from an online panel (971 adults who smoked cigarettes exclusively, 472 adults who dual used cigarettes and e-cigarettes and 458 adults aged 18-29 who had never smoked). Participants were randomised (parallel assignment) to one message condition: (1) VLNCs as harmful but easier to quit than regular cigarettes (n=468), (2) those who are not ready to quit should consider switching to e-cigarettes as less harmful alternatives (n=484), (3) combined (VLNC and e-cigarette messages; n=476) or (4) control condition (ie, water ads), n=473. The primary outcome was perceived absolute harm of VLNCs.

RESULTS: Perceived harm of VLNCs was higher in the VLNC condition compared with the e-cigarette and control conditions, and higher in the combined condition compared with the e-cigarette condition (adjusted p<0.05). Among adults who dual used, intention to switch to e-cigarettes was higher in the VLNC condition than the e-cigarette, combined or control conditions (adjusted p<0.05).

CONCLUSIONS: VLNC messages reduced the misperception that VLNCs are less harmful than cigarettes, but adding messages about e-cigarettes did not enhance desired outcomes. These VLNC messages can be considered during the rollout of a reduced nicotine policy.

TRIAL REGISTRATION: NCT05506046.