Gender and Menthol Cigarette Use in the United States: A Systematic Review of the Recent Literature (2011 - May 2017)

Smoking cessation prevalence by menthol cigarette use and select demographics among adults in the United States, TUS-CPS, 2003-2019

People who smoke menthol cigarettes, particularly those who are non-Hispanic Black/African American, are less likely to achieve successful smoking cessation compared with people who smoke non-menthol cigarettes. This study examined the 2003-2019 Tobacco Use Supplement to the Current Population Survey (TUS-CPS) harmonized data to estimate cross-sectional trends in cigarette smoking cessation among U.S. adults, stratified by menthol cigarette use, race/ethnicity, sex, and age. The analytic sample included respondents who smoked for ≥ 2 years (current users and former users who reported quitting during the past year). We tested cessation trends using orthogonal polynomial contrasts for overall, menthol, and non-menthol smoking cessation prevalence and stratified by race/ethnicity, sex, and age in logistic regression models. We also analyzed the 2018-2019 non-harmonized TUS-CPS data among recent quitters to examine differences in characteristics (e.g., demographic characteristics, smoking frequency, use of smoking cessation aids, switching to other tobacco products) by menthol cigarette use. We observed significant linear changes in prevalence trends for overall cigarette smoking cessation, menthol smoking cessation, and non-menthol smoking cessation (p < 0.0001 for all linear trends), and changes in menthol cessation among non-Hispanic White and non-Hispanic Other race/ethnicity categories during 2003-2019. In the 2018-2019 wave, we observed differences in menthol status for sex, race/ethnicity, age, and educational attainment. We did not observe differences for other characteristics. We observed changes in overall cigarette smoking cessation, menthol, and non-menthol smoking cessation prevalence during the study period; however, gains in cigarette smoking cessation were not experienced among non-Hispanic Black/African American adults who smoke.

Considerations of Sex and Gender in FDA Tobacco Regulation

This Viewpoint discusses how sex and gender subpopulations may be differentially affected by tobacco products and suggests that the FDA formulate regulations in clinically meaningful ways.

An Analysis of Twitter Posts About the U.S. Food and Drug Administration's Menthol Ban

INTRODUCTION

Although the U.S. Food and Drug Administration (FDA) banned characterizing flavors in cigarettes in 2009, this initial ban exempted menthol. After examining numerous reports on the adverse health effects of menthol cigarettes, the FDA proposed a menthol ban in April 2022. This study analyzed Twitter data to describe public reaction to this announcement.

AIMS AND METHODS

Posts containing the word "menthol" and/or "#menthol" were collected from April 21, 2022 to May 5, 2022 from Twitter's Streaming Application Programming Interface (API). A random sampling procedure supplied 1041 tweets for analysis. Following an inductive approach to content analysis, posts were classified into one or more of 11 themes.

RESULTS

Posts discussed the FDA announcement (n = 153, 14.7%), racial discrimination (n = 101, 9.7%), distrust in government (n = 67, 6.4%), inconsistencies between policies (n = 52, 5.0%), public health benefits (n = 42, 4%), freedom of choice (n = 22, 2.1%), and health equity (n = 21, 2.0%). Posts contained misinformation (n = 20, 1.9%), and discussed the potential for illicit markets (n = 18, 1.7%) and the need for cessation support (n = 4, 0.4%). 541 (52.0%) tweets did not fit into any of the prescribed themes.

CONCLUSIONS

Twitter posts with the word "menthol" commonly discussed distrust in government and mentioned racial discrimination. Findings demonstrated the possibility of near real-time Twitter monitoring of public opinion on a menthol ban. These data may be valuable for designing tobacco control health communication campaigns in the future.

IMPLICATIONS

The U.S. FDA proposed a ban on menthol cigarettes in April 2022. This study's content analyzed Twitter posts over a 2-week period to understand the public's response to the proposed menthol ban. Twitter posts with the word "menthol" often discussed distrust in government and mentioned racial discrimination. Findings demonstrated the possibility of near real-time Twitter monitoring of public opinion of regulatory action. Findings underscore the need to educate the public about the potential health benefits of banning menthol from cigarettes, particularly for populations that experience tobacco-related health disparities.

Profile of menthol cigarette smokers in the months following the removal of these products from the market: a cross-sectional population survey in England

INTRODUCTION

In May 2020, the EU Tobacco Products Directive ban on the sale of menthol cigarettes was implemented in England. This study examined the prevalence of menthol cigarette smoking after the ban, according to sociodemographic and smoking characteristics.

METHODS

Cross-sectional data came from a representative survey of current smokers (18+) in England (unweighted n=2681) between July 2020 and June 2021. The weighted prevalence of menthol cigarette smoking as a proportion of total cigarette smoking was calculated, log-binomial regression explored trends over time, and χ2 statistics assessed the relationship between menthol smoking, sociodemographic and smoking characteristics. Sources of purchase of menthol cigarettes were explored.

RESULTS

Between July 2020 and June 2021, 15.7% (95% CI 14.5 to 17.1) of smokers reported smoking menthol cigarettes. The fitted non-linear trend supported no initial change followed by a possible reduction across April-June 2021 and fit the data better than linear and null (no change) models (χ2(2)=2519.7, p=0.06; χ2(3)=2519.7, p=0.006). Menthol cigarette smoking was more common among younger groups (16-24=25.2%; 25-34=19.9%) and women (19.4%). Menthol cigarette smokers showed lower cigarette dependence compared with other smokers. Past-6-month purchases of menthol cigarettes from any illicit or cross-border source declined from 30.1% in the last 6 months of 2020 to 17.5% in the first 6 months of 2021.

CONCLUSIONS

A substantial minority of current smokers in England reported menthol cigarette smoking between July 2020 and June 2021, despite the ban, possibly reflecting mitigation of restrictions by a variety of licit means, such as legal menthol accessories. The reduction in menthol smoking across April-June 2021 warrants further monitoring.

Sociodemographic Differences in Menthol Cigarette Use in the United States

BACKGROUND

Menthol cigarette use is associated with higher smoking initiation and reduced smoking cessation. We investigated sociodemographic differences in menthol and nonmenthol cigarette use in the United States.

METHODS

We used the most recent available data from the May 2019 wave of the nationally-representative Tobacco Use Supplement to the Current Population Survey. The survey weights were used to estimate the national prevalence of individuals who currently smoke among individuals who use menthol and nonmenthol cigarettes. Survey-weighted logistic regression methods were used to estimate the association of menthol cigarette use with formerly smoking cigarettes and attempting to quit within the past 12 months while adjusting for several sociodemographic factors associated with smoking.

RESULTS

The prevalence of current smoking in individuals who ever smoked menthol cigarettes was higher 45.6% (44.5%-46.6%) compared to 35.8% (35.2%-36.4%) in individuals who ever smoked nonmenthol cigarettes. Non-Hispanics Blacks who used menthol cigarettes had a higher likelihood of being an individual who currently smokes (OR 1.8, 95% CI: [1.6-2.0], P-value <.001) compared to Non-Hispanic Whites who used nonmenthol cigarettes. However, Non-Hispanics Blacks who used menthol cigarettes were more likely to make a quit attempt (OR 1.4, 95%CI: [1.3-1.6], P-value <.001) compared to non-Hispanic Whites who used nonmenthol cigarettes.

CONCLUSIONS

Individuals who currently use menthol cigarettes are more likely to make attempts to quit smoking. However, this did not translate to successfully quitting smoking, as evidenced by the proportion of individuals who formerly smoked within the population which used menthol cigarettes.

Chemosensory Contributions of E-Cigarette Additives on Nicotine Use

While rates of smoking combustible cigarettes in the United States have trended down in recent years, use of electronic cigarettes (e-cigarettes) has dramatically increased, especially among adolescents. The vast majority of e-cigarette users consume "flavored" products that contain a variety of chemosensory-rich additives, and recent literature suggests that these additives have led to the current "teen vaping epidemic." This review, covering research from both human and rodent models, provides a comprehensive overview of the sensory implications of e-cigarette additives and what is currently known about their impact on nicotine use. In doing so, we specifically address the oronasal sensory contributions of e-cigarette additives. Finally, we summarize the existing gaps in the field and highlight future directions needed to better understand the powerful influence of these additives on nicotine use.

Genotypic Differences in the Effects of Menthol on Nicotine Intake and Preference in Mice

Menthol has been shown to exacerbate elements of nicotine addiction in humans and rodents; however, the mechanisms mediating its effects are not fully understood. This study examined the impact of genetic factors in menthol’s effects on oral nicotine consumption by comparing two inbred mouse strains with differing sensitivities to nicotine. C57BL/6J (B6J) mice are nicotine-preferring, while DBA/2J (D2J) mice are not. While the effects of menthol on oral nicotine consumption have been highlighted in B6J mice, it is unknown if they extend to the D2J strain as well. Consequently, adolescent (PND 21) and adult (PND 63), male and female D2J mice were subjected to the nicotine two-bottle choice (2BC) paradigm with orally and systemically administered menthol. Then, we evaluated its impact on nicotine pharmacological responses in conditioned reward and nociception after systemic administration and, lastly, investigated the potential involvement of the TAAR1 gene and α7 nAChRs in menthol’s effects. Menthol failed to enhance oral nicotine consumption in adult and adolescent female and male D2J mice. Moreover, this lack in effect was not due to nicotine concentration, oral aversion to menthol, or basal preference for nicotine. Menthol also failed to augment nicotine reward or enhance nicotine-induced antinociception in D2J mice, demonstrating that genetic background plays a significant role in sensitivity to menthol’s effects on nicotine. Furthermore, TAAR1 or α7 nAChRs did not seem to mediate menthol’s differential effects in D2J mice. These findings support the existence of genotype-specific mechanisms that may contribute to the variable effects of menthol in different populations.

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.

Racial Disparities in Cigarette Smoking Behaviors and Differences Stratified by Metropolitan Area of Residence

Background: Black cigarette smokers experience a disproportionate burden of non-small cell lung cancer (NSCLC) compared to other racial and ethnic groups, despite starting to smoke later in life, smoking less frequently, and smoking fewer cigarettes per day compared with White smokers. Research has shown that these disparities in NSCLC are wider in rural areas. Objective: To examine differences in smoking behaviors between Black and White individuals living in non-metropolitan areas and metropolitan areas. Methods: Using harmonized data from the Tobacco Use Supplement to the Current Population Survey (TUS-CPS) years 2010–2011, 2014–2015, and 2018–2019, we compared smoking behaviors between Black and White current and former smokers by metropolitan status (i.e., whether an individual lives in a densely populated area or not) and by both metropolitan status and sex. Results: Smoking prevalence was higher among White participants living in non-metropolitan versus Black participants. Further, in non-metropolitan areas, Black individuals reported smoking fewer cigarettes per day, fewer years of smoking, and a later age of initiation compared to White individuals. Additionally, Black individuals, especially men, were more likely than White individuals to be current non-daily smokers. Conclusions: Our findings show that Black individuals living in non-metropolitan areas do not, in aggregate, have more cigarette smoking exposure relative to White individuals. Additional research is needed to further understand smoking-related exposures and other factors that may contribute to lung cancer disparities, especially in non-metropolitan areas.

The Impact of Menthol Cigarette Flavor in the U.S.: Cigarette and ENDS Transitions by Sociodemographic Group

INTRODUCTION

A better understanding of how menthol cigarette flavoring and ENDS impact smoking initiation, cessation, and transitions between tobacco products could help elucidate the potential impact of a U.S. menthol ban on combustible tobacco products.

METHODS

A multistate transition model was applied to data on 23,232 adults from Waves 1-4 (2013-2017) of the Population Assessment of Tobacco and Health Study (analysis was conducted in 2020-2021). Transition rates among never, noncurrent, nonmenthol versus menthol cigarette, ENDS, and dual everyday/someday use were estimated, as were transition-specific hazard ratios for age, sex, race/ethnicity, education, and income.

RESULTS

Non-Hispanic Blacks who smoked menthol discontinued smoking at a much lower rate than those who smoked nonmenthol (hazard ratio=0.43, 95% CI=0.29, 0.64), but there was no statistically significant difference in the discontinuation rates among non-Hispanic Whites (hazard ratio=0.97, 95% CI=0.80, 1.16) or Hispanics (hazard ratio=0.81, 95% CI=0.56, 1.16). Non-Hispanic Whites who smoked menthol were more likely to become dual users than those who smoked nonmenthol (hazard ratio=1.43, 95% CI=1.14, 1.80). Young adults initiated menthol smoking at a higher rate than older adults (age 18-24 years versus ≥55 years: hazard ratio=2.45, 95% CI=1.44, 4.15) but not nonmenthol smoking (hazard ratio=1.02, 95% CI=0.62, 1.69). There were differences by sex in the impact of menthol flavor on smoking initiation and discontinuation but little difference by education or income.

CONCLUSIONS

Sociodemographic differences in product transitions should be accounted for when estimating the potential impact of a menthol ban.

Assessing the Health and Economic Impact of a Potential Menthol Cigarette Ban in New York City: a Modeling Study

Menthol in cigarettes increases nicotine dependence and decreases the chances of successful smoking cessation. In New York City (NYC), nearly half of current smokers usually smoke menthol cigarettes. Female and non-Latino Black individuals were more likely to smoke menthol-flavored cigarettes compared to males and other races and ethnicities. Although the US Food and Drug Administration recently announced that it will ban menthol cigarettes, it is unclear how the policy would affect population health and health disparities in NYC. To inform potential policymaking, we used a microsimulation model of cardiovascular disease (CVD) to project the long-term health and economic impact of a potential menthol ban in NYC. Our model projected that there could be 57,232 (95% CI: 51,967-62,497) myocardial infarction (MI) cases and 52,195 (95% CI: 47,446-56,945) stroke cases per 1 million adult smokers in NYC over a 20-year period without the menthol ban policy. With the menthol ban policy, 2,862 MI cases and 1,983 stroke cases per 1 million adults could be averted over a 20-year period. The model also projected that an average of $1,836 in healthcare costs per person, or $1.62 billion among all adult smokers, could be saved over a 20-year period due to the implementation of a menthol ban policy. Results from subgroup analyses showed that women, particularly Black women, would have more reductions in adverse CVD outcomes from the potential implementation of the menthol ban policy compared to males and other racial and ethnic subgroups, which implies that the policy could reduce sex and racial and ethnic CVD disparities. Findings from our study provide policymakers with evidence to support policies that limit access to menthol cigarettes and potentially address racial and ethnic disparities in smoking-related disease burden.

Evaluation of Flavor Effects on Oral Nicotine Liking and/or Disliking Using the Taste Reactivity Test in Rats

INTRODUCTION

Tobacco product flavors may change the sensory properties of nicotine, such as taste and olfactory cues, which may alter nicotine reward and aversion and nicotine taking behavior. The hedonic or aversive value of a taste stimulus can be evaluated by examining affective orofacial movements in rodents.

AIMS AND METHODS

We characterized taste responses to various oral nicotine concentrations using the taste reactivity test in rats. We also evaluated the impact of menthol and benzaldehyde (cherry, almond) flavorants on both ingestive and aversive responses to oral nicotine. Adult Sprague-Dawley rats (n = 5-10 per sex per group) were implanted with intraoral catheters and received 20 infusions (200 µl/ea). Nicotine (1-100 µg/mL) was evaluated in taste reactivity test to determine taste responses to nicotine. Later, the effects of menthol (50 µg/mL) and benzaldehyde (100 µg/mL) on the taste responses to nicotine were determined.

RESULTS

Nicotine at low concentrations (3 µg/mL in males, 1 µg/mL in females) elicited significantly greater ingestive responses compared with water, whereas higher nicotine concentrations (≥30 µg/mL in males, ≥10 µg/mL in females) elicited significant aversive reactions. Thus, intraoral nicotine induced both hedonic and aversive responses in a concentration- and sex-dependent manner. Females were more sensitive to nicotine's concentration. The addition of menthol or benzaldehyde significantly increased the hedonic responses to nicotine, and significantly decreased the aversive nicotine responses.

CONCLUSIONS

Oral nicotine induces both hedonic and aversive taste responses, which may represent liking and disliking. Menthol and benzaldehyde can alter the orosensory experience of nicotine, which may influence nicotine's abuse liability.

IMPLICATIONS

Our work represents a model to study impact of flavors on oral nicotine liking and disliking responses in rats. Moreover, our findings show that menthol and benzaldehyde alter the orosensory experience of nicotine, suggesting that both could influence nicotine's abuse liability.

Protein profiling in the habenula after chronic (-)-menthol exposure in mice

The identification of proteins that are altered following nicotine/tobacco exposure can facilitate and positively impact the investigation of related diseases. In this report, we investigated the effects of chronic (-)-menthol exposure in 14 murine brain regions for changes in total β2 subunit protein levels and changes in epibatidine binding levels using immunoblotting and radioligand binding assays. We identified the habenula as a region of interest due to the region's marked decreases in β2 subunit and nAChR levels in response to chronic (-)-menthol alone. Thus, we further examined the habenula, a brain region associated with both the reward and withdrawal components of addiction, for additional protein level alterations using mass spectrometry. A total of 552 proteins with altered levels were identified after chronic (-)-menthol exposure. Enriched in the proteins with altered levels after (-)-menthol exposure were proteins associated with signaling, immune systems, RNA regulation, and protein transport. The continuation and expansion of the brain region-specific protein profiling in response to (-)-menthol will provide a better understanding of how this common flavorant in tobacco and e-liquid products may affect addiction and general health.

Impact of menthol on nicotine intake and preference in mice: Concentration, sex, and age differences

Menthol has been shown to contribute to the appeal of tobacco products in humans. However, factors such as sex, age and menthol concentration remain unclear in the interaction between menthol and nicotine. To understand these factors, we utilized a mouse model to determine the impact of menthol on oral nicotine consumption. A range of menthol concentrations (oral and systemic) were tested with or without oral nicotine using the two-bottle choice paradigm in adolescent and adult female and male C57BL/6J mice. Moreover, genetically modified mice were used to investigate the role of α7 nicotinic acetylcholine receptors (nAChRs) on the effects of menthol. Menthol addition to nicotine solution increased oral nicotine consumption in C57BL/6J mice in a sex- and menthol concentration-dependent manner. At lower menthol concentrations, female mice demonstrated an enhancement of nicotine consumption and male mice showed a similar behavior at higher menthol concentrations. Menthol drinking alone was only significantly different by sex at 60 μg/ml menthol concentration where female mice had higher menthol intake than males. Menthol administered both orally and systemically (intraperitoneal) increased oral nicotine consumption. Adolescent female mice had a higher nicotine intake at lower menthol concentrations compared to their adult counterparts. While α7 nAChR wild type mice consumed more mentholated nicotine solution than nicotine only solution, this effect was abolished in KO mice. Effects of menthol are concentration-, sex-, age-, and α7 nAChR-dependent. Oral and intraperitoneal menthol increases nicotine intake, suggesting that sensory, peripheral, and/or central mechanisms are involved in effects of menthol on oral nicotine consumption.

Menthol blunts the interoceptive discriminative stimulus effects of nicotine in female but not male rats

RATIONALE

Menthol is a widely used tobacco constituent that has shown to enhance nicotine's reinforcing effects.

OBJECTIVE

To determine whether injected menthol also alters nicotine's stimulus effects, we used a drug discrimination task.

METHODS

A total of 57 adult Sprague-Dawley rats (28M, 29F) received 20 positive and 20 negative days (intermixed) of discrimination training. On positive days, rats received a group-specific menthol and nicotine injection (VEH + 0.1 NIC, 1 M + 0.1 NIC, 5 M + 0.1 NIC, VEH + 0.4 NIC, 1 M + 0.4 NIC, 5 M + 0.4 NIC; mg/kg) before eight 15-s cue light presentations (conditioned stimulus (CS)), each followed by 4-s sucrose access. On negative days, all rats were injected with vehicle and saline before eight non-reinforced CS presentations. Next, rats underwent generalization testing with 30 dose combinations of menthol and nicotine. The change in drug-mediated anticipatory goal tracking during the CS was calculated as a difference score (CS minus pre-CS responding).

RESULTS

All groups readily acquired drug discrimination. However, difference scores for the 5M + 0.1 NIC group were lower for females. Additionally, females had lower scores for 0.05, 0.1, and 0.4 mg/kg nicotine generalization tests. The lowest nicotine dose discriminable from saline was 0.05 mg/kg for females but 0.025 mg/kg for males. Co-administration with 5 or 10 mg/kg menthol weakened discrimination performance between 0.1 and 0.4 mg/kg and between 0.1 and 0.05 mg/kg nicotine for 0.1 mg/kg nicotine training groups.

CONCLUSIONS

Female rats that were trained with 0.1 mg/kg nicotine were more sensitive to menthol's modulatory effects on nicotine's stimulus effects. This highlights the importance of taking sex and training dose into account when evaluating the interoceptive stimulus effects of nicotine and menthol.

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.

Gender Differences in the Association between Marijuana and Menthol Cigarette Use among African American Adult Cigarette Smokers

Introduction: Despite the strong relationship between marijuana and tobacco use, especially among African American individuals and males, very few studies have examined the association between marijuana and menthol cigarette use. This study was designed to identify the prevalence of past month, past year and lifetime marijuana use and marijuana dependence among menthol and non-menthol cigarette smokers, as well as the association between marijuana and menthol cigarette use among African American female and male cigarette smokers. Methods: Data were drawn from 1,173 African American adult cigarette smokers in the 2017 National Survey on Drug Use and Health. Results: Overall, 8.8%, 13.9% and 44.7% of African American menthol and non-menthol cigarette smokers reported past month, past year and lifetime marijuana use, respectively. Weighted multivariable logistic regression models revealed a significant interaction between gender and past month marijuana use on menthol cigarette use (AOR = 1.49, 95% CI: 1.21-2.42, p < .05). Past month marijuana use was associated with an increased odds of past month menthol cigarette use (relative to non-menthol cigarette use) among females, but a decreased odds of past of past month menthol cigarette use among males. Conclusions: When stratified by gender, marijuana use is differentially related to menthol cigarette use among African American adults. Given the prevalence of menthol cigarette use among this population, it is important to examine factors such as marijuana use that could be targeted in prevention and treatment interventions for African Americans, especially females, who are at risk for smoking or are currently smoking menthol cigarettes. Implications: This study found that marijuana use was associated with an increased odds of menthol cigarette use among African American females, while marijuana use was associated with a decreased odds of menthol cigarette use among their male counterparts. The impact of marijuana use on menthol cigarette smoking differs among females and males, highlighting the need for gender-tailored interventions that target marijuana use among African American individuals, especially females, who are at risk for smoking or are currently smoking menthol cigarettes.

Influence of the E-Cigarette Emission Profile by the Ratio of Glycerol to Propylene Glycol in E-Liquid Composition

The use of electronic cigarettes (E-cig) is popular because of the perception that they are less addictive and safer compared to the traditional cigarettes. Nevertheless, there are still harmful effects associated with chemicals emitted from E-cig. Identifying the sources of the emitted compounds can be challenging because of the differences in the design of E-cig devices and the variability in the composition of E-cig liquids used in these devices. In this study, the emission profiles from impurity-free E-liquids containing only propylene glycol and glycerol in various percentage ratios along with two commercially available E-liquids were evaluated using gas chromatography-mass spectrometry (GC-MS). This study approach allows the elucidation of the transformation pathways of the major emitted compounds without the confounding effects of existing impurities or flavor ingredients added to E-liquids. Analysis of the vapor phases of E-cig emissions detected toxicants such as acetaldehyde, acrolein, benzaldehyde, as well as benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. The amount of glycerol in the E-liquids has a major effect on the concentration of these hazardous compounds emitted because the concentration of these chemicals increased with increasing glycerol percentage in the E-liquid. Acetaldehyde and acrolein increased by 175-fold and 28-fold, respectively, when the glycerol composition was increased from 0 to 80%. Benzaldehyde, naphthalene, diphenyl ether, and glycerol along with menthol and nicotine that were present in the commercial E-liquids were also detected in the aerosol condensates. The cascade impactor data on the distribution of the nicotine and menthol in different size fractions from >2.5 to <2.5 μm allow the estimates of the extent of toxicant deposition in different parts of the pulmonary system including the oropharynx region, the trachea as well as inside the alveoli and bronchioles. In summary, users of E-cig are exposed to harmful chemicals even if the E-liquids contain only propylene glycol and glycerol without flavorings, nicotine, or impurities. Furthermore, this study shows that E-liquids containing higher percentages of glycerol will produce higher levels of toxicants compared to E-liquids with similar percentages of propylene glycol. This finding has important implications to E-cigarette vendors and manufacturers, consumers, and regulatory agencies.