Tobacco control environment in the United States and individual consumer characteristics in relation to continued smoking: differential responses among menthol smokers?

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

Background

The 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?”

Methods

Six 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).

Results

Forty-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.

Conclusions

Given 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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13011-021-00397-4.

Use of Mentholated Cigarettes and Likelihood of Smoking Cessation in the United States: A Meta-Analysis

INTRODUCTION

Previous qualitative reviews have summarized evidence of an association between menthol cigarette use and likelihood of smoking cessation. The objective of this meta-analysis was to provide a quantitative summary of effect sizes, their variability, and factors related to the variability in effect size for the association between menthol use and likelihood of smoking cessation.

METHODS

We systematically searched Medline, PsycINFO, and Embase for prospective and cross-sectional studies of the association between menthol use and smoking cessation. We analyzed data with random effects meta-analyses and meta-regression.

RESULTS

Our review identified 22 reports from 19 studies of the association between menthol use and cessation. All identified study samples included only US smokers, with one exception that included both Canadian and US smokers. Our overall model did not demonstrate a significant association between menthol use and cessation; however, menthol users were significantly less likely to quit among blacks/African American smokers (odds ratio = 0.88).

CONCLUSIONS

Among blacks/African Americans predominantly in the US menthol users have approximately 12% lower odds of smoking cessation compared to non-menthol users. This difference is likely the result of the tobacco industry's ongoing marketing influence on the black/African American Community, suggesting that a menthol ban may have a unique public health benefit for black/African American smokers by encouraging quitting behavior.

IMPLICATIONS

This study adds a quantitative summary of the association between menthol cigarette use and smoking cessation in the United States. Findings of an association with lower likelihood of cessation among black/African American smokers, likely resulting from the tobacco industry's marketing influence, support the ban of menthol flavoring as part of a comprehensive tobacco control effort to increase cessation among black/African American smokers.

Examining e-cigarette purchases and cessation in a consumer panel of smokers

Objectives

Examine correlates of initiation of e-cigarette use among smokers and determine the impact of e-cigarette use on cessation among smokers in a national U.S. consumer panel.

Methods

This study used the Nielsen Homescan Panel data from 2011 to 2013, augmented with state-specific measures of tobacco control activities, to examine 1) correlates of single and repeat e-cigarette purchasing among panelists currently purchasing cigarettes; and 2) correlates of "cessation". Participating panelists scanned all retail purchases, and Nielsen recorded over 3 million product types. The key explanatory variable for cessation was e-cigarette purchase. Parallel analysis was conducted for conventional nicotine replacement therapy (NRT) purchase. Cessation was defined as no purchases for at least 6 months and no subsequent purchases until the end of 2013. Analysis was conducted in 2015. E-cigarettes tracked by Nielsen during this period were cig-a-like products resembling tobacco cigarettes in appearance.

Results

Single e-cigarette purchase was associated with whether the panelist resided in a single person male household and bought a higher volume of cigarettes. Repeat purchase was associated with higher state cigarette taxes, less stringent state public smoke-free policies, lower cigarette prices, and more frequent cigarette purchasing. Cessation was associated with repeat e-cigarette purchasing, repeat NRT purchasing, younger age, lower monthly cigarette volume, less frequent purchasing of cigarettes, less recent cigarette purchase at baseline, and single e-cigarette purchase before baseline.

Conclusions

Both individual and policy variables were associated with e-cigarette use. Repeat e-cigarette purchase was associated with cigarette purchase discontinuation, as were various smoking intensity measures.

Effects of Menthol Flavor Cigarettes or Total Urinary Menthol on Biomarkers of Nicotine and Carcinogenic Exposure and Behavioral Measures

INTRODUCTION

The effects of either menthol flavor cigarettes or total urinary menthol on nicotine dependence, biomarkers of addictive and carcinogenic exposure, and behavioral measures may inform differences and similarities of these two approaches.

METHODS

Stratified recruitment by cigarette (menthol flavor or regular) and race (African American and white) yielded a balanced sample of 136 adult smokers in a 36-hour inpatient protocol. Exposure measures assessed during 24-hour data collection included urinary menthol, total NNAL [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol], 10 polycyclic aromatic hydrocarbon metabolites, baseline plasma cotinine, plasma nicotine pre- and post-smoking, exhaled carbon monoxide pre- and post-smoking, and cigarette puff volumes. The latter three were measured at four specified timepoints throughout the day.

RESULTS

There were no significant differences between menthol flavor and regular cigarette smokers in measures of nicotine dependence, biomarkers of addictive and carcinogenic exposures, or behavioral measures. Significant race × cigarette type interaction effects were found for two biomarkers: plasma nicotine and 3-hydroxyphenanthrene. Total urinary menthol was significantly associated with higher levels of nearly all dependent variables including puff volume, exhaled carbon monoxide, plasma nicotine and cotinine, NNAL, and polycyclic aromatic hydrocarbons. The significant effects of total urinary menthol were sustained after adjusting for menthol flavor and regular cigarette type and other covariates (eg, number of cigarettes per day, baseline cotinine, and baseline nicotine).

CONCLUSIONS

Urinary menthol is an independent predictive biomarker for nicotine dependence, addictive and carcinogenic exposure, and behaviors.

IMPLICATIONS

Comparison of the effects of menthol flavor and total urinary menthol on nicotine dependence, biomarkers of addictive and carcinogenic exposure, and behavioral measures emphasizes the important significant contribution of total urinary menthol concentrations in contrast to no significant associations by dichotomous cigarette type with these biomarkers.

Menthol cigarettes and the public health standard: a systematic review

Background

Although menthol was not banned under the Tobacco Control Act, the law made it clear that this did not prevent the Food and Drug Administration from issuing a product standard to ban menthol to protect public health. The purpose of this review was to update the evidence synthesis regarding the role of menthol in initiation, dependence and cessation.

Methods

A systematic review of the peer-reviewed literature on menthol cigarettes via a PubMed search through May 9, 2017. The National Cancer Institute’s Bibliography of Literature on Menthol and Tobacco and the FDA’s 2011 report and 2013 addendum were reviewed for additional publications. Included articles addressing initiation, dependence, and cessation were synthesized based on study design and quality, consistency of evidence across populations and over time, coherence of findings across studies, and plausibility of the findings.

Results

Eighty-two studies on menthol cigarette initiation (n = 46), dependence (n = 14), and cessation (n = 34) were included. Large, representative studies show an association between menthol and youth smoking that is consistent in magnitude and direction. One longitudinal and eight cross-sectional studies demonstrate that menthol smokers report increased nicotine dependence compared to non-menthol smokers. Ten studies support the temporal relationship between menthol and reduced smoking cessation, as they measure cessation success at follow-up.

Conclusions

The strength and consistency of the associations in these studies support that the removal of menthol from cigarettes is likely to reduce youth smoking initiation, improve smoking cessation outcomes in adult smokers, and in turn, benefit public health.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4987-z) contains supplementary material, which is available to authorized users.

Slowing Menthol's Progress: Differential Impact of a Tobacco Tax Increase on Cigarette Sales

OBJECTIVES

The proportion of smokers who use menthol cigarettes has increased nationally since 2004, while use of non-menthol cigarettes is declining, suggesting that menthol may be undermining the effectiveness of population level tobacco control efforts. In 2013 Minnesota passed a $1.75 cigarette tax increase. We investigated whether sales of menthol and non-menthol cigarettes were differentially affected by the price increase.

METHODS

Cigarette sales data from convenience stores in the Minneapolis, Minnesota, metro area from January 2012, through May 2015, were obtained. Proportion of sales accounted for by menthol cigarettes was analyzed with segmented regression.

RESULTS

Before the price increase, menthol cigarettes gained 2.21% (1.17, 3.12) of market share annually. Following the price increase, the trend slowed to 0.26% (-0.78, 1.56) annually. The slope before the price increase was significantly positive; the slope following the price increase did not significantly differ from zero.

CONCLUSIONS

Sales of menthol cigarettes declined less rapidly than non-menthol cigarettes before the price increase. Sales of menthol and non-menthol cigarettes declined at more comparable rates after the price increase. Increasing the price of tobacco may help ensure declines in consumption are more evenly distributed across menthol and non-menthol cigarettes.

IMPLICATIONS

Using sales data, we found that a trend of increasing market share for menthol cigarettes was significantly reduced by a $1.75 cigarette price increase. These results suggest that cigarette price increases, a core tobacco control policy, may have a greater effect on menthol smokers than non-menthol smokers.

Why We Must Continue to Investigate Menthol's Role in the African American Smoking Paradox

BACKGROUND

The disproportionate burden of tobacco use among African Americans is largely unexplained. The unexplained disparities, referred to as the African American smoking paradox, includes several phenomena. Despite their social disadvantage, African American youth have lower smoking prevalence rates, initiate smoking at older ages, and during adulthood, smoking rates are comparable to whites. Smoking frequency and intensity among African American youth and adults are lower compared to whites and American Indian and Alaska Natives, but tobacco-caused morbidity and mortality rates are disproportionately higher. Disease prediction models have not explained disease causal pathways in African Americans. It has been hypothesized that menthol cigarette smoking, which is disproportionately high among African Americans, may help to explain several components of the African American smoking paradox.

PURPOSE

This article provides an overview of the potential role that menthol plays in the African American smoking paradox. We also discuss the research needed to better understand this unresolved puzzle.

METHODS

We examined prior synthesis reports and reviewed the literature in PubMed on the menthol compound and menthol cigarette smoking in African Americans.

RESULTS

The pharmacological and physiological effects of menthol and their interaction with biological and genetic factors may indirectly contribute to the disproportionate burden of cigarette use and diseases among African Americans.

CONCLUSIONS

Future studies that examine taste sensitivity, the menthol compound, and their effects on smoking and chronic disease would provide valuable information on how to reduce the tobacco burden among African Americans.

IMPLICATIONS

Our study highlights four counterintuitive observations related to the smoking risk profiles and chronic disease outcomes among African Americans. The extant literature provides strong evidence of their existence and shows that long-standing paradoxes have been largely unaffected by changes in the social environment. African Americans smoke menthols disproportionately, and menthol's role in the African American smoking paradox has not been thoroughly explored. We propose discrete hypotheses that will help to explain the phenomena and encourage researchers to empirically test menthol's role in smoking initiation, transitions to regular smoking and chronic disease outcomes in African Americans.

National Surveys and Tobacco Use Among African Americans: A Review of Critical Factors

INTRODUCTION

Beginning in the 1970s, US national surveys showed African American youth having a lower prevalence of cigarette smoking than white youth. Yet, during adulthood, African Americans have a smoking prevalence comparable to white adults. Data sources chosen can contribute in different ways to understanding tobacco use behaviors among African American youth and adults; this article is a review of national and/or state-based health surveys to examine their methodology, racial and ethnic classifications, and tobacco-use related measures.

METHODS

Eleven national and/or state based surveys were selected for review. Eight surveys were multitopic and included questions on tobacco use and three surveys were tobacco specific. Survey methods included telephone (4), household (3), and school (4). Three major characteristics examined for each survey were: (1) survey design and methods, (2) racial and ethnic background classification, and (3) selected tobacco smoking questions. Within these three characteristics, 15 factors considered to be important for examining tobacco use behaviors by African Americans were identified a priori using previously published reviews and studies.

RESULTS

Within survey design and methods, the majority of surveys (≥7) oversampled African Americans and did not use proxy respondents for tobacco questions. All surveys used Office of Management and Budget standard classification for race/ethnicity classification. The majority of surveys (≥7) captured five of the seven tobacco-related smoking questions.

CONCLUSIONS

Programmatic objectives and/or research questions should guide the selection of data sources for tobacco control programs and researchers examining African American tobacco use behaviors.

IMPLICATIONS

This review of 11 national and state tobacco-related surveys shows that these surveys provide much needed estimates of tobacco use behaviors. However, as tobacco programs and researchers seek to examine tobacco use behaviors among African Americans, it is important to consider multiple surveys as each can contribute to informing the tobacco experience in African Americans. Most importantly, programmatic objectives and/or research questions should guide the selection of data sources for tobacco control programs and researchers examining African American tobacco use behaviors.

An exploratory analysis of cigarette price premium, market share and consumer loyalty in relation to continued consumption versus cessation in a national US panel

INTRODUCTION

Brand equity and consumer loyalty play a role in continued purchasing behaviour; however, this research has largely focused on non-addictive products without counter-marketing tactics. We examined the impact of brand equity (price premium, market share) and consumer loyalty (switching rates) on smoking cessation (discontinued cigarette purchases for 1 year) among smokers in a consumer panel.

METHODS

In Spring 2015, we analysed 1077 cigarette-purchasing households in the Nielsen Homescan Panel. We analysed cessation in relation to brand equity, consumer loyalty, other purchasing behaviours (nicotine intake, frequency), sociodemographics and tobacco control activities (per state-specific data) over a 6-year period (2004-2009) using Cox proportional hazard modelling.

RESULTS

The sample was 13.28% African-American; the average income was $52,334 (SD=31,445). The average price premium and market share of smokers' dominant brands were $1.31 (SD=0.49) and 15.41% (SD=19.15), respectively. The mean brand loyalty level was 0.90 (SD=0.17), indicating high loyalty. In our final model, a higher price premium and market share were associated with lower quit rates (p=0.039); however, an interaction effect suggested that greater market share was not associated with lower cessation rates for African-American smokers (p=0.006). Consumer loyalty was not associated with cessation. Other predictors of lower quit rates included a higher nicotine intake (p=0.006) and baseline purchase frequency (p<0.001). Tobacco control factors were not significantly associated.

CONCLUSIONS

Smokers of high-equity cigarette brands are less likely to quit, perhaps due to strong brand-consumer relationships. Thus, continued efforts should aim to regulate tobacco marketing efforts in order to disrupt these relationships to promote cessation.

The lingering question of menthol in cigarettes

Tobacco use is the single most important preventable cause of cancer-related deaths in the USA and many parts of the world. There is growing evidence that menthol cigarettes are starter tobacco products for children, adolescents, and young adults. Accumulating research also suggests that smoking menthol cigarettes reinforces nicotine dependence, impedes cessation, and promotes relapse. However, menthol cigarettes are exempt from the US Food and Drug Administration ban on flavored cigarettes due, in part, to the lack of empirical evidence describing the health consequences of smoking menthol cigarettes relative to regular cigarettes. Determining the biological effects of menthol cigarette smoke relative to regular cigarette smoke can clarify the health risks associated with the use of respective products and assist regulatory agencies in making scientifically based decisions on the development and evaluation of regulations on tobacco products to protect public health and to reduce tobacco use by minors. We highlight the inherent shortcomings of the conventional epidemiologic, clinical, and laboratory research on menthol cigarettes that have contributed to the ongoing debate on the public health impact of menthol in cigarettes. In addition, we provide perspectives on how future investigations exploiting state-of-the-art biomarkers of exposure and disease states can help answer the lingering question of menthol in cigarettes.