Assessing the evidence on the differential impact of menthol versus non-menthol cigarette use on smoking cessation in the U.S. population: a systematic review and meta-analysis

Table 1 Inclusion and Exclusion Criteria for Key Questions (KQs)

	Inclusion Criteria	Exclusion Criteria
Population	• Youth and adults • Current or former smokers with explicit use of (or stated preference for) menthol or non-menthol cigarettes; studies of non-smokers were eligible if they reported a measure of initiation • United States residents	• Studies of never-smokers at any time point • Studies of only non-United States residents
Comparisons	• Menthol versus non-menthol • Delivery of nicotine via traditional cigarettes	• Studies reporting only menthol or non-menthol or not directly comparing menthol with non-menthol • Studies of non-traditional tobacco delivery^a
Outcomes	• Duration of abstinence; quit attempts (any quit attempts; number of quit attempts per person); rate of abstinence/quitting (including but not limited to prolonged abstinence [PA], point prevalence abstinence [PPA], identifiable cigarette type [menthol versus non-menthol] smoked before quitting, and being a former smoker [versus current smoker]); Change in smoking quantity/frequency; return to smoking/relapse	• Any other outcomes
Study Designs^b	• Randomized and non-randomized controlled trials • Cross-sectional, case-control, and cohort studies • Letters and editorials containing original data not available elsewhere were eligible	• Reviews, case reports, editorials, and letters not containing original data

^a E.g., vaporizers, e-cigarettes, hookahs/water pipes
^b Reclassification of included trials as cross-sectional or cohort depending on the eligible data as follows: if only baseline data used from a trial, it was considered a cross-sectional study; if any post-baseline measurement data was used, it was considered it a cohort

ISSN: 1747-597X