Assessing the Evidence on the Differential Impact of Menthol versus Non-menthol Cigarette Use on Initiation and Progression to Regular Smoking: A Systematic Review and Meta-analysis.

Background: Despite numerous assessments of the public health impact of menthol cigarettes, a rigorous synthesis related to menthol cigarettes and behavioral outcomes is lacking. This systematic review and meta-analysis examined the question: Does menthol cigarette use have a differential impact on initiation and progression to regular smoking compared to non-menthol cigarette use? Methods: We consulted 6 databases from their inception to October 15, 2021. We included articles comparing menthol versus non-menthol smokers among 4 predefined smoking initiation and progression outcomes. We assessed risk of bias was using the Agency for Healthcare Research and Quality Evidence-Based Practice Center approach. We applied a random-effects model to pool adjusted odds ratios. Results: We qualitatively synthesized 16 adjusted studies across the outcomes. Results from one meta-analysis suggested no difference between menthol and non-menthol smokers in likelihood to report daily versus non-daily smoking. Conclusion: This systematic review and meta-analysis did not identify a consistent, statistically significant, or differential association between menthol use and progression to regular smoking. Varying definitions of outcome measures and lack of longitudinal evidence limited the confident conclusions that could be drawn from this evidence base.