Menthol versus non-menthol flavouring and switching to e-cigarettes in black and Latinx adult menthol combustible cigarette smokers: secondary analyses from a randomised clinical trial.

BACKGROUND: As the US Food and Drug Administration takes regulatory action on menthol cigarettes, debate continues about how restricting menthol e-liquids might impact adult menthol smokers in switching to e-cigarettes. METHODS: Switching patterns and e-cigarette acceptability were assessed at week 6 among 64 black and Latinx menthol cigarette smokers who used JUUL menthol (n=39) or non-menthol e-cigarettes ((n=25), primarily mint or mango) as part of a randomised switching trial. RESULTS: No clear evidence of effects was found between menthol versus non-menthol e-cigarettes on use or subjective effects/acceptability, effect sizes for all comparisons were small (effect size=0.0-0.2), and Bayes factor ranged from 0.10 to 0.15. Specifically, 82.1% of participants who used menthol-flavoured e-cigarettes fully or partially switched to e-cigarettes compared with 88.0% of participants who used a non-menthol (p=0.75). Further, both groups demonstrated substantial reductions in cigarettes per day (menthol e-cigarettes: -8.5±10.4 vs non-menthol e-cigarettes: -8.8±5.8, p=0.87), comparable grams of e-liquid consumed (menthol e-cigarettes: 9.2±9.8 g vs non-menthol e-cigarettes: 11.0±11.0 g, p=0.47), and positive subjective effects, including 'just right' throat hit (menthol e-cigarettes: 70.7% vs non-menthol e-cigarettes: 66.7%, p=0.93) and flavour liking (menthol e-cigarettes: 75.6% vs non-menthol e-cigarettes: 66.7%, p=0.32). CONCLUSIONS: Both menthol and non-menthol e-cigarettes were associated with high rates of use and acceptability among menthol smokers. Findings require confirmation in a fully powered non-inferiority or equivalence study but provide preliminary evidence to inform regulatory action on menthol e-cigarettes that could slow youth initiation without impacting black and Latinx menthol cigarette smokers interested in switching to e-cigarettes. TRIAL REGISTRATION NUMBER: NCT03511001.