Search

Objective: Following AMSTAR 2 and PRISMA guidelines, in this synthesis of evidence we sought to identify and characterize any associations between e-cigarette use among cigarette smokers and cigarette smoking quit attempts. Methods: We queried 3 databases from January 1, 2007 to January 5, 2021. Search results were screened using the PICOS review method. Included studies examined e-cigarette use and cigarette smoking quit attempts across e-cigarette use statuses. Risk of bias was assessed according to the Agency for Healthcare Research and Quality Evidence-Based Practice Center approach. Finally, 4 random-effects models compared e-cigarette users and non- e-cigarette-users in terms of past year and prospective (6 to 12 months) cigarette smoking quit attempts. Results: We qualitatively synthesized 17 adjusted studies for this review. Two meta-analyses showed past year quit attempts were significantly associated with current e-cigarette users and 2 prospective data analyses found no significant association. Conclusions: The results of the meta- analyses emphasize temporality in the association between e-cigarette use and cigarette smoking quit attempts. Numerous methodological limitations, including inadequate definitions of e-cigarette use and non-adjustment for confounding variables, limit the confidence in conclusions that can be drawn on the causal association between e-cigarette use and cigarettes smoking quit attempts.

Background: Menthol's effect on cigarette smoking behaviors is an intensely scrutinized US public health issue. This systematic review and meta-analysis examined the question: Does menthol cigarette use have a differential impact on smoking dependence compared with non-menthol cigarette use? Methods: We consulted 6 databases from inception to October 15, 2021. We included articles comparing menthol versus non-menthol cigarette smokers against predefined smoking dependence outcomes. Risk of bias was assessed using the AHRQ Evidence-Based Practice Center approach. We applied a random-effects model to pool adjusted odds ratios. Results: We synthesized 37 demographically adjusted studies. Meta-analytic results suggested non-menthol smokers were equally/more likely to report daily versus non-daily smoking; menthol use was associated with needing a cigarette within one hour; cigarettes per day was not associated with menthol use; menthol use was associated with a low (vs high) Heaviness of Smoking Index score; and results were either non-significant or associated menthol use with lower TTFC. Conclusions: Despite consistently good or fair quality adjusted studies across several measures, results were discordant depending on measures used and means of measurement. Overall, the evidence is insufficient to draw clear conclusions on a differential association between menthol (vs non-menthol) cigarette use and smoking dependence.

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.

BackgroundThe potential impact of menthol versus non-menthol cigarette use on smoking behaviors is an intensely scrutinized topic in the public health arena. To date, several general literature reviews have been conducted, but findings and conclusions have been discordant. This systematic review followed PRISMA guidelines to examine the Key Question, “Does menthol cigarette use have a differential impact on smoking cessation compared with non-menthol cigarette use?”MethodsSix databases—Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, MEDLINE, Embase and PsycInfo—were queried from inception to June 12, 2020. Articles comparing menthol versus non-menthol cigarette smokers in terms of at least one predefined smoking cessation outcome were included. Risk of bias was assessed using the Agency for Healthcare Research and Quality Evidence-Based Practice Center approach. A random-effects model utilizing the DerSimonian and Laird method to pool adjusted odds ratio was applied. Variations among pooled studies were assessed using Cochran’s Q statistic, and heterogeneity was quantified using the inconsistency index (I2).ResultsForty-three demographically adjusted studies (22 rated “good”, 20 rated “fair”, and one study rated “poor” individual study quality) comparing menthol and non-menthol smokers were qualitatively synthesized across the following measures (study count; strength of evidence): duration of abstinence (2; low); quit attempts (15; insufficient); rate of abstinence/quitting (29; moderate); change in smoking quantity/frequency (5; insufficient); and, return to smoking/relapse (2; insufficient). Overall, the qualitative synthesis failed to show a consistent trend for an association between menthol cigarette use and smoking cessation across outcomes. Meta-analyses found no difference between menthol and non-menthol cigarette use and either quit attempts or abstinence.ConclusionsGiven the lack of consistency or statistical significance in the findings—combined with a “low” overall strength of evidence grade, based on deficiencies of indirectness and inconsistency—no consistent or significant associations between menthol cigarette use and smoking cessation were identified. Recommendations for future studies include increased focus on providing longitudinal, adjusted data collected from standardized outcome measures of cessation to better inform long-term smoking cessation and menthol cigarette use. Such improvements should also be further considered in more methodologically rigorous systematic reviews characterized by objectivity, comprehensiveness, and transparency with the ultimate objective of better informing public health and policy decision making.

Introduction Various approaches have been used to estimate the population health impact of introducing a Modified Risk Tobacco Product (MRTP). Aims and Methods We aimed to compare and contrast aspects of models considering effects on mortality that were known to experts attending a meeting on models in 2018. Results Thirteen models are described, some focussing on e-cigarettes, others more general. Most models are cohort-based, comparing results with or without MRTP introduction. They typically start with a population with known smoking habits and then use transition probabilities either to update smoking habits in the “null scenario” or joint smoking and MRTP habits in an “alternative scenario”. The models vary in the tobacco groups and transition probabilities considered. Based on aspects of the tobacco history developed, the models compare mortality risks, and sometimes life-years lost and health costs, between scenarios. Estimating effects on population health depends on frequency of use of the MRTP and smoking, and the extent to which the products expose users to harmful constituents. Strengths and weaknesses of the approaches are summarized. Conclusions Despite methodological differences, most modellers have assumed the increase in risk of mortality from MRTP use, relative to that from cigarette smoking, to be very low and have concluded that MRTP introduction is likely to have a beneficial impact. Further model development, supplemented by preliminary results from well-designed epidemiological studies, should enable more precise prediction of the anticipated effects of MRTP introduction. Implications There is a need to estimate the population health impact of introducing modified risk nicotine-containing products for smokers unwilling or unable to quit. This paper reviews a variety of modeling methodologies proposed to do this, and discusses the implications of the different approaches. It should assist modelers in refining and improving their models, and help toward providing authorities with more reliable estimates.

Introduction Several published systematic reviews have examined the potential associations between e-cigarette use and cigarette smoking, but their methodological and/or reporting quality have not yet been assessed. This systematic quality review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and AMSTAR (A MeaSurement Tool to Assess systematic Reviews) 2 to evaluate the quality of systematic reviews investigating potential associations between e-cigarette use and cigarette smoking. Materials and methods PubMed/MEDLINE, Embase, and PsycINFO were searched from 01 January 2007 to 24 June 2020. Methodological quality was assessed using AMSTAR 2, and reporting quality was assessed using PRISMA guidelines. Results Of 331 potentially relevant systematic reviews, 20 met predefined inclusion criteria. Most reviews (n = 15; 75%) reported on e-cigarette use and cigarette smoking cessation, while three reported on e-cigarette use and cigarette smoking initiation (15%); and two reported on cigarette smoking initiation and cessation (10%). According to AMSTAR 2 guidelines, 18 of the 20 reviews (90%) were “critically low” in overall confidence of the results, while two were ranked “low.” Additionally, reporting quality varied across the reviews, with only 60% reporting at least half of the PRISMA items. Discussion Methodological limitations were identified across reviews examining potential associations between e-cigarette use and cigarette smoking behaviors, indicating that findings from these reviews should be interpreted with caution. Conclusions Future systematic reviews in this field should strive to adhere to AMSTAR 2 and PRISMA guidelines, to provide high quality syntheses of the available data with transparent and complete reporting.

Though available evidence is relatively consistent in showing no additional health effects among smokers due to menthol in cigarettes, two studies reported conflicting results for stroke risk using different subsets of NHANES data. We investigated reasons for the differences in these reports by analyzing NHANES cycles conducted between 1999 and 2012, combined and in subsets. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) from three different survey logistic regression models compare risk of reported stroke diagnoses among menthol and non-menthol cigarette smokers. Depending on timeframe, about 1150 to 8000 U.S. adults (aged ≥ 20 years) who smoked on ≥ 1 of the last 30 days had complete data for cigarette type and all covariates included in each model. Results were not much affected by which covariates were included in the models, but depended strongly on the NHANES cycles included in the analysis. Using NHANES 1999–2012 data combined, AORs and 95% CIs for stroke comparing menthol with non-menthol cigarette smokers were 0.95 (95% CI: 0.65, 1.37), 0.85 (95% CI: 0.59, 1.23) or 0.86 (95% CI: 0.59, 1.25). Collectively, findings illustrate the need for fully reporting research and analytical methods, especially when analyses are meant to develop evidence intended for regulatory decision-making.

There are no large-scale, carefully designed cohort studies that provide evidence on whether menthol cigarette use is associated with a differential risk of initiating and/or progressing to increased smoking. However, questions of whether current menthol cigarette smokers initiated smoking at a younger age or are more likely to have transitioned from non-daily to daily cigarette use compared to non-menthol smokers can be addressed using cross-sectional data from U.S. government surveys. Analyses of nationally representative samples of adult and youth smokers indicate that current menthol cigarette use is not associated with an earlier age of having initiated smoking or greater likelihood of being a daily versus non-daily smoker. Some surveys likewise provide information on cigarette type preference (menthol versus non-menthol) among youth at different stages or trajectories of smoking, based on number of days smoked during the past month and/or cigarettes smoked per day. Prevalence of menthol cigarette use does not appear to differ among new, less experienced youth smokers compared to established youth smokers. While there are limitations with regard to inferences that can be drawn from cross-sectional analyses, these data do not suggest any adverse effects for menthol cigarettes on measures of initiation and progression to increased smoking.

Previously published studies provide somewhat inconsistent evidence on whether menthol in cigarettes is associated with increased dependence. The National Health and Nutrition Examination Survey, National Survey on Drug Use and Health, National Health Interview Survey, and Tobacco Use Supplement to the Current Population Survey collect data on current cigarette type preference and primary measures of dependence, and thus allow examination of whether menthol smokers are more dependent than non-menthol smokers. Analyses based on combined data from multiple administrations of each of these four nationally representative surveys, using three definitions for current smokers (i.e., smoked ⩾1 day, ⩾10 days and daily during the past month), consistently demonstrate that menthol smokers do not report smoking more cigarettes per day than non-menthol smokers. Moreover, two of the three surveys that provide data on time to first cigarette after waking indicate no difference in urgency to smoke among menthol compared to non-menthol smokers, while the third suggests menthol smokers may experience a greater urgency to smoke; estimates from all three surveys indicate that menthol versus non-menthol smokers do not report a higher Heaviness of Smoking Index. Collectively, these findings indicate no difference in dependence among U.S. smokers who use menthol compared to non-menthol cigarettes.

Selected toxicant concentrations and other chemical measures have been determined for 43 U.S. smokeless tobacco products sold in 2006 and 2007. Products evaluated included moist snuff, dry snuff, loose leaf, plug, dissolvable and snus tobacco brands. Reference products available for scientific research purposes and eleven Swedish products were also evaluated and compared to the commercial products studied. Chemical endpoints determined included benzo[a]pyrene (B[a]P), N'-nitrosonornicotine (NNN), N'-nitrosoanatabine (NAT), N'-nitrosoanabasine (NAB), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-Nitrosodimethylamine (NDMA), nitrite, cadmium, lead, arsenic, nickel, chromium, chloride, water, pH and nicotine. Different toxicant profiles were observed for the products studied, with snus tobacco brands generally containing relatively low concentrations of B[a]P and tobacco specific nitrosamines (TSNAs) compared to other moist snuffs. Smokeless tobacco reference product toxicant profiles were similar to corresponding commercial products, with the exception of the TSNA content of the dry snuff reference material. TSNA concentrations observed for all commercial products were lower than historically reported values, likely reflecting changes in product shelf life, tobacco curing practices and, possibly, product blend formulations during the last 20-30 years. The survey results summarized provide a temporal point of comparison with future data anticipated from FDA "harmful and potentially harmful constituents in tobacco products" reporting.

Menthol in cigarettes has been examined for its potential to affect smoking dependence, measured primarily as number of cigarettes smoked per day and time to first cigarette after waking; the ability to quit smoking constitutes an additional measure of dependence. Successful quitting among menthol compared to non-menthol cigarette smokers is difficult to determine from the literature, due in part to the various definitions of quitting used by researchers. Nevertheless, intervention and follow-up studies of smoking cessation treatments generally indicate no differences in quitting success among menthol compared to non-menthol smokers, while cross-sectional studies suggest some differences within race/ethnicity groups. The association between menthol cigarette use and likelihood of being a former versus current smoker was examined based on data from the National Health Interview Survey and Tobacco Use Supplement to the Current Population Survey. Analyses stratified by race/ethnicity and limited to smokers who had quit at least one year prior to survey participation provided inconsistent results with regard to menthol cigarette use and quitting, both within surveys (i.e., comparing race/ethnicity groups) and between surveys (i.e., same race/ethnicity group across surveys). Evidence suggesting the existence or direction of an association between menthol in cigarettes and quitting depended on the data source.

The National Health and Nutrition Examination Survey, National Survey on Drug Use and Health, National Health Interview Survey and Tobacco Use Supplement to the Current Population Survey provide estimates of the proportions of U.S. smokers who currently use menthol cigarettes, overall and within demographic strata. Among adult past-month, regular and daily smokers, menthol cigarette use ranges from 26% to 30%, with statistically higher proportions of female versus male smokers (8–11 percentage points higher) currently using menthol cigarettes. Compared to adult smokers overall, statistically higher proportions of non-Hispanic Black smokers (72–79%) and statistically lower proportions of non-Hispanic White smokers (19–22%) currently use menthol cigarettes, with no differences among smokers of other race/ethnicity groups (18–20% to 28–30%, depending on the survey). Higher proportions of younger adult past-month, regular and daily smokers (aged 18–25years) currently use menthol cigarettes compared to older adult smokers (aged 26–29years and/or ⩾30years); however, differences are small in magnitude, with the vast majority of adult smokers (70–75%) who currently use menthol cigarettes being aged ⩾30years. Comparisons between youth and adult smokers are provided, although data for youth smokers are less available and provide less consistent patterns of menthol cigarette use.