Sensory properties of menthol and smoking topography

The Effects of Changes in Cigarette Menthol Content on Acute Nicotine Pharmacology and Smoking Topography

INTRODUCTION

Menthol influences the appeal and addictiveness of cigarette smoking, however the data regarding menthol's effects on nicotine pharmacokinetics (PK) and smoking topography are inconsistent. This study investigated the impact of different cigarette menthol levels on nicotine pharmacology and smoking topography in current menthol smokers.

AIMS AND METHODS

The study was a double-blind, randomized, four-period, crossover study to investigate the effects of smoking cigarettes with varying menthol content (0, 3, 6, and 12 mg menthol) on nicotine PK, smoking topography, and subjective effects in current menthol smokers. Each experimental session consisted of a prescribed use session, followed by 145 min of no smoking and a 1-h ad libitum smoking session. Serial blood samples were collected; smoking topography was recorded using CReSS Lab topography device.

RESULTS

There was no significant effect of menthol on nicotine PK after prescribed smoking of cigarettes with varying menthol contents. During ad libitum smoking, there was significantly smaller total puff volume and puff duration in the 12 mg menthol condition compared to other menthol conditions. Subjective and sensory measures indicated significantly higher overall positive ratings for the 3 mg and 6 mg menthol cigarettes compared to the 0 mg menthol cigarette; the 12 mg menthol cigarette was less liked and harsher than the 3 mg condition.

CONCLUSIONS

These findings suggest that menthol, at concentrations reflecting the marketplace (3-6 mg), contributes to positive subjective smoking experiences among menthol smokers, but does not have a significant effect on nicotine PK or smoking topography in an acute laboratory setting.

IMPLICATIONS

While our data indicate that varying menthol content does not have a significant impact on nicotine's pharmacological effects under acute exposure conditions, these data highlight the contribution of menthol's flavor and sensory effects to product preference and positive smoking experiences, which facilitate repeated experimentation, progression to regular use, and subsequent dependence.

Effects of liquid nicotine concentration and flavour on the acceptability of electronic nicotine delivery systems (ENDS) among people who smoke participating in a randomised controlled trial to reduce cigarette consumption

BACKGROUND

Research is needed to understand the acceptability of electronic nicotine delivery systems (ENDS) as a smoking reduction aid. This study examines the acceptability of ENDS by liquid nicotine concentration and flavour among people who smoke using ENDS to reduce their smoking.

METHODS

People who smoke cigarettes but were naïve to ENDS participated in a double-blind randomised controlled trial to reduce conventional cigarette smoking. Participants were randomised to either a control cigarette substitute (CS) or one of three ENDS groups; 0 mg/mL, 8 mg/mL or 36 mg/mL nicotine concentration. ENDS flavour was chosen by the participant (tobacco or menthol). Participants reported their CS, ENDS and cigarettes per day (CPD) from the past 7 days at 1-month, 3-month and 6-month follow-up visits. Participants also reported side effects and measures of satisfaction, psychological reward, aversion and craving relief. Outcome variables were modelled using linear mixed effects by the following groups: liquid nicotine concentration, flavour and a flavour-nicotine concentration interaction.

RESULTS

Participants (n=520) were 41.2% male, 67.3% white, had a mean age of 46.2 years and smoked a mean of 18.6 CPD (SD=7.74) at baseline. All flavour and concentration groups decreased CPD from baseline to all follow-up visits with the 36 mg/mL experiencing the greatest reduction, compared with the 0 mg/mL and 8 mg/mL groups. All groups except the 36 mg/mL group decreased their product use over time. The use of menthol flavour was associated with fewer side effects at 3 months (p=0.02) and lesser aversion at 1 month (p=0.03) compared with tobacco-flavoured ENDS. The 36 mg/mL group experienced the greatest craving relief and greatest aversion compared with other groups.

CONCLUSIONS

Both nicotine concentration and flavour appear to have independent, as well as interactive, effects that influence ENDS acceptability among people who use cigarettes.

Substitutability of menthol cigarette alternatives: a clinical trial

INTRODUCTION

This study assessed the substitutability of plausible combustible menthol cigarette alternatives (MCAs) for usual brand menthol cigarettes (UBMCs) in adults who smoke menthol cigarettes.

METHODS

Following three in-lab sampling sessions, 80 adults aged 21-50 who smoke menthol cigarettes chose their preferred MCA: (1) a menthol roll-your-own cigarette (mRYO), (2) a menthol filtered little cigar (mFLC) or (3) a non-menthol cigarette (NMC). Participants were instructed to completely substitute their preferred MCA for their UBMC for 1 week and complete daily diaries documenting adherence and subjective effects. At the final lab visit, participants completed concurrent choice and cross-price elasticity tasks with their substitute product and UBMC as the comparator.

RESULTS

Most (65%) participants chose mRYO as their preferred product, followed by NMC and mFLC. Adherence to MCA was high for all products across the week (range: 63%-88%). Positive subjective effects for mRYO decreased over time but remained numerically higher than the other MCA products; craving reduction also decreased for NMC across phases. In the progressive ratio task, participants chose their UBMC in 61.7% of choices; this did not differ by preferred MCA, although the median breakpoint was highest for mRYO and similar for mFLC and NMC. Cross-price elasticity comparing UBMC and the preferred product indicated high substitutability of each MCA at phase 3 (I values -0.70 to -0.82).

CONCLUSIONS AND RELEVANCE

mRYOs were the most preferred MCA among the study products, but all MCAs were acceptable substitutes for UBMC using behavioural and economic measures in a short-term trial period.Trial registration number NCT04844762.

Heterogeneous deposition of regular and mentholated little cigar smoke in the lungs of Sprague-Dawley rats

BACKGROUND

Quantifying the dose and distribution of tobacco smoke in the respiratory system is critical for understanding its toxicity, addiction potential, and health impacts. Epidemiologic studies indicate that the incidence of lung tumors varies across different lung regions, suggesting there may be a heterogeneous deposition of smoke particles leading to greater health risks in specific regions. Despite this, few studies have examined the lobar spatial distribution of inhaled particles from tobacco smoke. This gap in knowledge, coupled with the growing popularity of little cigars among youth, underscores the need for additional research with little cigars.

RESULTS

In our study, we analyzed the lobar deposition in rat lungs of smoke particles from combusted regular and mentholated Swisher Sweets little cigars. Twelve-week-old male and female Sprague-Dawley rats were exposed to smoke particles at a concentration of 84 ± 5 mg/m3 for 2 h, after which individual lung lobes were examined. We utilized Inductively Coupled Plasma Mass Spectrometry to quantify lobar chromium concentrations, serving as a smoke particle tracer. Our findings demonstrated an overall higher particle deposition from regular little cigars than from the mentholated ones. Higher particle deposition fraction was observed in the left and caudal lobes than other lobes. We also observed sex-based differences in the normalized deposition fractions among lobes. Animal study results were compared with the multi-path particle dosimetry (MPPD) model predictions, which showed that the model overestimated particle deposition in certain lung regions.

CONCLUSIONS

Our findings revealed that the particle deposition varied between different little cigar products. The results demonstrated a heterogenous deposition pattern, with higher particle deposition observed in the left and caudal lobes, especially with the mentholated little cigars. Additionally, we identified disparities between our measurements and the MPPD model. This discrepancy highlights the need to enhance the accuracy of models before extrapolating animal study results to human lung deposition. Overall, our study provides valuable insights for estimating the dose of little cigars during smoking for toxicity research.

How Do Herbal Cigarettes Compare To Tobacco? A Comprehensive Review of Their Sensory Characters, Phytochemicals, and Functional Properties

Herbal cigarettes, known as tobacco-free or nicotine-free cigarettes, are those recognized as being-tobacco free, being composed of a mixture of various herbs claimed to lessen the smoking habit hazards. However, controversial data regarding its properties occur in the literature with no comprehensive overview or analysis of its effects. Like herbal smokeless tobacco, they are often used to substitute for tobacco products (primarily cigarettes) regarded as a "nonsmoking" aid. This review capitalizes on herbal cigarettes with regard to their quality characteristics, sensory attributes, chemical composition, and health properties to rationalize their choice as a nonsmoking aid. Furthermore, the impacts of heat and/or pyrolysis that occur during smoking on its chemical composition are presented for the first time. Some herbal smokes may produce notable metabolic problems that increase the risk of several chronic metabolic diseases. In general, burning substances from plants can have a variety of negative effects on the body attributed to toxic chemicals such as carbon monoxide, polyaromatics, nicotine, and N-nitrosamines. This review compiles and discusses the phytochemical compositions detected in various herbal cigarettes alongside sensory and quality attributes and health effects.

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.

Racial disparities in intensity of smoke exposure and nicotine intake among low-dependence smokers

BACKGROUND

Compared to white smokers, Black smokers are at disproportionately higher risk for smoking-related disease, despite consuming fewer cigarettes per day (CPD). To examine racial disparities in biobehavioral influences on smoking and disease risk, we analyzed the relationship between self-reported tobacco dependence and intensity of tobacco smoke exposure per cigarette, on the one hand, and intensity of nicotine intake per cigarette, on the other.

METHODS

In 270 Black and 516 white smokers, smoke exposure was measured by expired carbon monoxide (CO), and nicotine intake was measured by plasma cotinine (COT) and cotinine+3'-hydroxycotinine ([COT + 3HC]). Using linear regression analyses, we analyzed how the Fagerström Test for Cigarette Dependence (FTCD) predicted intensity of smoke exposure per cigarette (CO/CPD) and intensity of nicotine intake per cigarette (COT/CPD; [COT + 3HC]/CPD), and how race moderated these relations.

RESULTS

Overall, Black smokers consumed fewer CPD than white smokers and had higher levels of CO/CPD, COT/CPD, and [COT + 3HC]/CPD. These elevations were most pronounced at lower levels of dependence: amongst Black smokers, FTCD negatively predicted intensity of smoke exposure as measured by CO/CPD (B = -0.12, 95% CI = -0.18, -0.05, p = 0.0003) and intensity of nicotine intake as measured by [COT + 3HC]/CPD (B = -1.31, 95% CI = -2.15, -0.46, p = 0.002).

CONCLUSIONS

Low-dependence Black smokers had higher intensities of both smoke exposure and nicotine intake per cigarette compared to similarly dependent white smokers, suggesting that measures of dependence, exposure, and intake underestimate incremental risk of each cigarette to Black smokers.

Current Knowledge on the Vascular Effects of Menthol

Menthol is a monoterpene alcohol, widely used in several food and healthcare products for its particular odor and flavor. For some decades, menthol has been known to act on the vasculature directly in the endothelium and vascular smooth muscle, with recent studies showing that it also evokes an indirect vascular response via sensory fibers. The mechanisms underlying menthol's vascular action are complex due to the diversity of cellular targets, to the interplay between signaling pathways and to the variability in terms of response. Menthol can evoke either a perfusion increase or decrease in vivo in different vascular territories, an observation that warrants a critical discussion. Menthol vascular actions in vivo seem to depend on whether the vascular territory under analysis has been directly provoked with menthol or is located deep/distant to the application site. Menthol increases perfusion of directly provoked skin regions due to a complex interplay of increased nitric oxide (NO), endothelium-derived hyperpolarization factors (EDHFs) and sensory nerve responses. In non-provoked vascular beds menthol decreases perfusion which might be attributed to heat-conservation sympathetically-mediated vasoconstriction, although an increase in tissue evaporative heat loss due the formulation ethanol may also play a role. There is increasing evidence that several of menthol's cellular targets are involved in cardiovascular diseases, such as hypertension. Thus menthol and pharmacologically-similar drugs can play important preventive and therapeutic roles, which merits further investigation.

Role of l- and d-Menthol in the Glucuronidation and Detoxification of the Major Lung Carcinogen, NNAL

Menthol, which creates mint flavor and scent, is often added to tobacco in both menthol and nonmenthol cigarettes. A potent tobacco carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is extensively metabolized to its equally carcinogenic metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as (R)- or (S)-NNAL enantiomers. NNAL is detoxified by UDP-glucuronosyltransferase (UGT) enzymes, with glucuronidation occurring on either NNAL's pyridine ring nitrogen (NNAL-N-Gluc) or the chiral alcohol [(R)- or (S)-NNAL-O-Gluc]. To characterize a potential effect by menthol on NNAL glucuronidation, in vitro menthol glucuronidation assays and menthol inhibition of NNAL-Gluc formation assays were performed. Additionally, NNAL and menthol glucuronides (MG) were measured in the urine of smokers (n = 100) from the Southern Community Cohort Study. UGTs 1A9, 1A10, 2A1, 2A2, 2A3, 2B4, 2B7, and 2B17 all exhibited glucuronidating activity against both l- and d-menthol. In human liver microsomes, both l- and d-menthol inhibited the formation of each NNAL-Gluc, with a stereospecific difference observed between the formation of (R)-NNAL-O-Gluc and (S)-NNAL-O-Gluc in the presence of d-menthol but not l-menthol. With the exception of three nonmenthol cigarette smokers, urinary MG was detected in all menthol and nonmenthol smokers, with l-MG comprising >98% of total urinary MG. Levels of urinary NNAL-N-Gluc were significantly (P < 0.05) lower among subjects with high levels of total urinary MG; no significant changes in free NNAL were observed. These data suggest that the presence of menthol could lead to increases in alternative, activating metabolic pathways of NNAL in tobacco target tissues, increasing the opportunity for NNAL to damage DNA and lead to the development of tobacco-related cancers. SIGNIFICANCE STATEMENT: High levels of the major menthol metabolite, menthol-glucuronide, was observed in the urine of smokers of either menthol or nonmenthol cigarettes. The fact that a significant inverse correlation was observed between the levels of urinary menthol-glucuronide and NNAL-N-glucuronide, a major detoxification metabolite of the tobacco carcinogen, NNK, suggests that menthol may inhibit clearance of this important tobacco carcinogen.

Menthol cigarette use in young adult smokers with severe mental illnesses

INTRODUCTION

Smokers with severe mental illness (SMI) are more likely to start smoking and less likely to quit. Menthol may facilitate smoking progression, dependence, and maintenance by reducing harshness and irritation from smoking and providing a unique sensory experience during use. High rates of menthol use have been reported in smokers with SMI, but information on young adults with SMI has not been reported.

METHODS

This study provides a secondary analysis to assess the impact of menthol use in a pilot trial of brief tobacco interventions. Participants were assessed at baseline and again at a 3-month follow-up with structured interviews and breath carbon monoxide to confirm self-reported 7-day abstinence at follow-up.

RESULTS

Participants included 81 young adult smokers with SMI, mean age of 24.2 years (SD = 3.6; range 18-30). Overall, 58% of the group reported that they recently used a menthol-flavored product. Menthol use was correlated with race (African American [18/21, 85.7%] vs. White [24/53, 45.3%] or other race [5/7, 71.4%]; χ2 = 10.7, p = .005) and more lifetime psychiatric hospitalizations (t = 2.39, p = .02), but not with cigarettes per day, nicotine dependence, quit attempts over the follow-up period, nor with achieving biologically confirmed abstinence at the follow-up assessment.

CONCLUSIONS

The high prevalence of menthol-flavored cigarette use in this study group is consistent with previous reports of high rates of menthol use among young adults, Blacks, and middle-aged SMI smokers. This study supports existing evidence that policies to restrict menthol flavoring in combustible tobacco products could reduce smoking in young adults with SMI.

IMPLICATIONS

High rates of menthol use have been reported in middle-aged smokers with SMI, but information on young adults with SMI has not been reported. In this study, more than half (58%) of 81 young adult smokers with SMI used a menthol-flavored product. Menthol use was associated with race and with history of psychiatric hospitalizations. The research supports existing evidence that policies to restrict menthol flavoring in combustible tobacco products could reduce smoking in young adults with SMI.

Effect of menthol on nicotine intake and relapse vulnerability in a rat model of concurrent intravenous menthol/nicotine self-administration

RATIONALE

Epidemiological data suggest that menthol may increase vulnerability to cigarette/nicotine use and relapse. While menthol's sensory properties are often attributed as the underlying cause of the enhanced vulnerability, an alternative possibility is that they are mediated via pharmacological interactions with nicotine.

OBJECTIVE

This study addressed the possibility that menthol enhances nicotine intake and relapse vulnerability via pharmacological interactions with nicotine using a concurrent intravenous menthol/nicotine self-administration procedure.

METHODS

Following acquisition, adolescent rats were given 23-h/day access to nicotine (0.01 mg/kg/infusion), nicotine plus menthol (0.16, 0.32, or 0.64 mg/kg/infusion), or menthol alone (0.16, 0.32, 0.64 mg/kg/infusion) for a total of 10 days. Nicotine-seeking was assessed using an extinction/cue-induced reinstatement procedure following 10 days of forced abstinence. We also assessed the effect of menthol (0.32 mg/kg/infusion) on progressive ratio responding for nicotine (0.01 mg/kg/infusion).

RESULTS

Menthol decreased PR responding for nicotine but did not affect self-administration under extended access conditions. The low dose of menthol tended to decrease subsequent extinction responding, and was not different from menthol alone, whereas the high dose decreased reinstatement responding. Although not significant, the highest levels of extinction responding were observed in a minority of rats in the moderate and high menthol-nicotine groups; rats in these groups also took longer to extinguish.

CONCLUSIONS

Taken together, these results demonstrate that pharmacological interactions of menthol with nicotine reduce, rather than increase, nicotine's reinforcing effects and some measures of relapse vulnerability. Importantly, however, moderate and high menthol doses may increase some aspects of relapse vulnerability in a minority of individuals.

Menthol Cigarette Smoke Induces More Severe Lung Inflammation Than Non-menthol Cigarette Smoke Does in Mice With Subchronic Exposure - Role of TRPM8

In smokers with chronic obstructive pulmonary disease, more severe lung inflammation is associated with menthol cigarette smoking compared to non-menthol cigarette smoking. However, the mechanisms remain unclear. Menthol is an activator of transient receptor potential melastatin-8 (TRPM8), which is also sensitive to reactive oxygen species (ROS). Our recent in vitro study demonstrated that the extracts of menthol cigarette smoke (M-CS) can induce greater ROS-sensitive, TRPM8-mediated, mitogen-activated protein kinase (MAPK)-dependent inflammatory responses in lung epithelial cells than the extracts of non-menthol cigarette smoke (Non-M-CS) can. In this study, we tested the hypothesis that M-CS can induce more severe lung inflammation than Non-M-CS can via the additional action of menthol in M-CS on epithelial and lung TRPM8 in mice. Compared with Non-M-CS exposure, subchronic M-CS exposure for 7 days up-regulated the epithelial and lung expression of TRPM8, induced more vigorous activation of epithelial and lung MAPKs, and caused more severe lung inflammation. The MAPK activation was evidenced by the increased expression of phosphor-extracellular signal-regulated and phosphor-c-Jun N-terminal kinases. The lung inflammation was evidenced by pathohistological findings and increases in several inflammatory indices. Moreover, treatment with a TRPM8 antagonist (N-(3-aminopropyl)-2-{[(3-methylphenyl)methyl]oxy}-N-(2-thienylmethyl)benzamide; AMTB) greatly suppressed the MAPK activation and lung inflammation induced by Non-M-CS and M-CS, and the residual responses to these two types of CS did not differ. Conversely, the levels of biomarkers of acute CS exposure (20 min), including carboxyhemoglobin and cotinine (a nicotine metabolite) in blood plasma, and superoxide and hydrogen peroxide (two major types of ROS) in bronchoalveolar lavage fluid, did not show significant differences in the mice with Non-M-CS and M-CS exposure. We concluded that M-CS could induce greater TRPM8-mediated activation of MAPKs and lung inflammation than Non-M-CS could in mice with subchronic exposure. The augmented inflammatory effects of M-CS are unlikely due to a larger total amount of CS inhaled, but may be caused by an additional stimulation of epithelial and lung TRPM8 by menthol in M-CS. A common stimulant (presumably ROS) generated by both CS types may also stimulate TRPM8, activate MAPKs, and induce lung inflammation because treatment with AMTB could reduce these responses to Non-M-CS.

Differences in Subjective Experiences to First Use of Menthol and Nonmenthol Cigarettes in a National Sample of Young Adult Cigarette Smokers

Purpose

Menthol has been hypothesized to ease the harshness of cigarette smoke. Thus, sensory experiences at first cigarette use may be one mechanism by which menthol facilitates progression to regular smoking. This study examined differences in subjective experiences to the first use of a menthol versus nonmenthol cigarette among new young adult smokers.

Methods

Data were drawn from waves 5-8 of the Truth Initiative Young Adult Cohort Study, a national sample of 18-34 year olds assessed every 6 months. Analyses included a subset of young adult current smokers (n = 251) who initiated smoking in the past 6 months. Subjective responses to first cigarette use were assessed across menthol and nonmenthol initiators in bivariate analyses and adjusted models controlling for smoking correlates.

Results

Fifty-two percent of new young adult smokers used a menthol cigarette at first use. First use of a menthol cigarette was higher in those aged 18-24 (vs. 25-34). Most black smokers (93.1%) were menthol initiators compared to 43.9% of white smokers. More than half of menthol and nonmenthol initiates felt relaxed or calm, dizzy, lightheaded, liking the taste and a rush or buzz at first use. Menthol initiators were less likely in bivariate and multivariable analyses to experience feeling nauseated at first use (adjusted odds ratio = 0.45; p = .020) compared to nonmenthol initiators.

Conclusions

While few differences were found between menthol and nonmenthol initiators in their subjective experiences, fewer menthol initiates felt nauseated at first cigarette use. Future research needs to identify additional mechanisms linking menthol initiation to smoking progression.

Implications

Menthol initiators were more likely to be younger (18-24 vs. 25-34), and black (vs. white) compared to nonmenthol initiators. Our finding that menthol initiators were less likely to feel nauseated at first cigarette use compared to nonmenthol initiators suggests that menthol may reduce aversion to early cigarette use among young smokers and thus has the potential to facilitate continued experimentation. Interventions and policy approaches to reduce tobacco use initiation and progression are urgently needed in young people.

Assessment of the abuse liability of three menthol Vuse Solo electronic cigarettes relative to combustible cigarettes and nicotine gum

RATIONALE

We previously reported that following a short-term product use period, use of non-menthol Vuse Solo electronic cigarettes (ECs) resulted in product effect-related subjective responses and nicotine uptake between those of combustible cigarettes (high-abuse liability comparator) and nicotine gum (low-abuse liability comparator); the results were generally closer to those of nicotine gum.

OBJECTIVE

Using a similar design to the previous study, we evaluated the abuse liability of three menthol-flavored Vuse Solo ECs with the same nicotine contents (14, 29, and 36 mg) in a group of EC-naïve, menthol cigarette smokers, relative to comparator products.

METHODS

Six-hour nicotine uptake and ratings of subjective effects were used to determine abuse liability and pharmacokinetics.

RESULTS

Use of menthol Vuse Solo resulted in significantly lower responses to subjective measurements (product liking, intent to use product again, and liking of positive product effects), higher urge to smoke responses, and a lower peak (Cmax) and overall extent (AUC0-360) of nicotine uptake compared to smoking the usual brand menthol cigarette. When compared with use of nicotine gum, subjective responses to use of menthol Vuse ECs were in the same direction as those resulting from smoking cigarettes but were more similar to nicotine gum use in magnitude than they were to cigarettes.

CONCLUSION

These findings are concordant with our previous results and provide evidence that menthol Vuse Solo ECs have abuse liability that is lower than menthol cigarettes and potentially greater than that of nicotine gum.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02664012.

Particulate matter emissions of different brands of mentholated cigarettes

Inhaling particulate matter (PM) in environmental tobacco smoke (ETS) endangers the health of nonsmokers. Menthol, an additive in cigarettes, attenuates respiratory irritation of tobacco smoke. It reduces perceptibility of smoke and therefore passive smokers may inhale ETS unnoticed. To investigate a possible effect of menthol on PM concentrations (PM₁₀, PM_2.5, and PM₁), ETS of four mentholated cigarette brands (Elixyr Menthol, Winston Menthol, Reyno Classic, and Pall Mall Menthol Blast) with varying menthol content was analyzed. ETS was generated in a standardized way using an automatic environmental tobacco smoke emitter (AETSE), followed by laser aerosol spectrometry. This analysis shows that the tested cigarette brands, despite having different menthol concentrations, do not show differences with regard to PM emissions, with the exception of Reyno Classic, which shows an increased emission, although the menthol level ranged in the midfield. More than 90% of the emitted particles had a size smaller than or equal to 1 µm. Regardless of the menthol level, the count median diameter (CMD) and the mass median diameter (MMD) were found to be 0.3 µm and 0.5 µm, respectively. These results point out that there is no effect of menthol on PM emission and that other additives might influence the increased PM emission of Reyno Classic.

IMPLICATIONS

Particulate matter (PM) in ETS endangers the health of nonsmokers and smokers. This study considers the effect of menthol, an additive in cigarettes, on PM emissions. Does menthol increase the amount of PM? Due to the exposure to secondhand smoke nearly 900,000 people die each year worldwide. The aim of the study is to measure the particle concentration (L^-1), mass concentration (µg m^-3), and dust mass fractions shown as PM₁₀, PM_2.5, and PM₁ of five different cigarette brands, including four with different menthol concentrations and one menthol-free reference cigarette, in a well-established standardized system.

Effect of e-liquid flavor on electronic cigarette topography and consumption behavior in a 2-week natural environment switching study

Electronic Nicotine Delivery Systems (ENDS) offer an alternate means to consume nicotine in a variety of flavored aerosols. Data are needed to better understand the impact of flavors on use behavior. A natural environment observational study was conducted on experienced ENDS users to measure the effect of e-liquid flavor on topography and consumption behavior. The RIT wPUMTM monitor was used to record to record the date and time and puff topography (flow rate, volume, duration) for every puff taken by N = 34 participants over the course of two weeks. All participants used tobacco flavor for one week, and either berry or menthol flavor for one week. Results provide strong evidence that flavor affects the topography behaviors of mean puff flow rate and mean puff volume, and there is insufficient evidence to support an influence of flavor on mean puff duration and mean puff interval. There was insufficient evidence, due to the low power associated with the limited number of observation days, to establish a relationship between flavor and cumulative consumption behavior. While the results indicate that an effect may be evident, additional observation days are required to establish significance.

Does menthol cigarette use moderate the effect of nicotine metabolism on short-term smoking cessation?

The nicotine metabolite ratio (NMR) has been shown to predict response to the transdermal nicotine patch, such that faster nicotine metabolism is associated with a lower abstinence rate. Menthol cigarette use, versus nonmenthol cigarette use, slows nicotine metabolism and therefore may attenuate the effect of NMR on smoking abstinence. In this study, we evaluated whether cigarette type (menthol vs. nonmenthol) modified the association between NMR and short-term abstinence. This was a secondary analysis examining treatment in the first 8 weeks of 21 mg/day nicotine patch therapy in a completed clinical trial (n = 474). Menthol cigarette use was based on self-report. NMR was defined dichotomously (0 = fast, 1 = slow) to distinguish between fast (≥0.47) versus slow NMR. Using logistic regression analysis, we tested whether cigarette type moderated the association between NMR and bioverified 7-day point prevalence abstinence at Week 8. Covariates include nicotine dependence, age, race, and gender. Three hundred two participants reported smoking menthol cigarettes, of which 234 (77%) were classified as slow NMR. Among the 172 nonmenthol smokers, 136 were classified as slow NMR (79%). Contrary to our expectations, the NMR ×Cigarette Type interaction effect on abstinence was not significant (odds ratio [OR] = 0.91, p = .86). Excluding the interaction variable, fast NMR was associated with decreased likelihood of abstinence (OR = 0.55, p = .03), but menthol cigarette use was not (OR = 1.15, p = .56). Further exploration of risk factors among menthol cigarette smokers, especially among racially diverse and light smokers, could clarify the association between menthol cigarette use and poorer smoking outcomes. (PsycINFO Database Record

Inflammatory Effects of Menthol vs. Non-menthol Cigarette Smoke Extract on Human Lung Epithelial Cells: A Double-Hit on TRPM8 by Reactive Oxygen Species and Menthol

Clinical studies suggest that smokers with chronic obstructive pulmonary disease who use menthol cigarettes may display more severe lung inflammation than those who smoke non-menthol cigarette. However, the mechanisms for this difference remain unclear. Menthol is a ligand of transient receptor potential melastatin-8 (TRPM8), a Ca²⁺-permeant channel sensitive to reactive oxygen species (ROS). We previously reported that exposure of human bronchial epithelial cells (HBECs) to non-menthol cigarette smoke extract (Non-M-CSE) triggers a cascade of inflammatory signaling leading to IL-8 induction. In this study, we used this in vitro model to compare the inflammatory effects of menthol cigarette smoke extract (M-CSE) and Non-M-CSE and delineate the mechanisms underlying the differences in their impacts. Compared with Non-M-CSE, M-CSE initially increased a similar level of extracellular ROS, suggesting the equivalent oxidant potency. However, M-CSE subsequently produced more remarkable elevations in intracellular Ca²⁺, activation of the mitogen-activated protein kinases (MAPKs)/nuclear factor-κB (NF-κB) signaling, and IL-8 induction. The extracellular ROS responses to both CSE types were totally inhibited by N-acetyl-cysteine (NAC; a ROS scavenger). The intracellular Ca²⁺ responses to both CSE types were also totally prevented by NAC, AMTB (a TRPM8 antagonist), or EGTA (an extracellular Ca²⁺ chelator). The activation of the MAPK/NF-κB signaling and induction of IL-8 to both CSE types were suppressed to similar levels by NAC, AMTB, or EGTA. These results suggest that, in addition to ROS generated by both CSE types, the menthol in M-CSE may act as another stimulus to further activate TRPM8 and induce the observed responses. We also found that menthol combined with Non-M-CSE induced greater responses of intracellular Ca²⁺ and IL-8 compared with Non-M-CSE alone. Moreover, we confirmed the essential role of TRPM8 in these responses to Non-M-CSE or M-CSE and the difference in these responses between the both CSE types using HBECs with TRPM8 knockdown and TRPM8 knockout, and using HEK293 cells transfected with hTRPM8. Thus, compared with exposure to Non-M-CSE, exposure to M-CSE induced greater TRPM8-mediated inflammatory responses in HBECs. These augmented effects may be due to a double-hit on lung epithelial TRPM8 by ROS generated from CSE and the menthol in M-CSE.

Metabolomic profiles of current cigarette smokers

Smoking-related biomarkers for lung cancer and other diseases are needed to enhance early detection strategies and to provide a science base for tobacco product regulation. An untargeted metabolomics approach by ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF MS) totaling 957 assays was used in a novel experimental design where 105 current smokers smoked two cigarettes 1 h apart. Blood was collected immediately before and after each cigarette allowing for within-subject replication. Dynamic changes of the metabolomic profiles from smokers' four blood samples were observed and biomarkers affected by cigarette smoking were identified. Thirty-one metabolites were definitively shown to be affected by acute effect of cigarette smoking, uniquely including menthol-glucuronide, the reduction of glutamate, oleamide, and 13 glycerophospholipids. This first time identification of a menthol metabolite in smokers' blood serves as proof-of-principle for using metabolomics to identify new tobacco-exposure biomarkers, and also provides new opportunities in studying menthol-containing tobacco products in humans. Gender and race differences also were observed. Network analysis revealed 12 molecules involved in cancer, notably inhibition of cAMP. These novel tobacco-related biomarkers provide new insights to the effects of smoking which may be important in carcinogenesis but not previously linked with tobacco-related diseases. © 2016 Wiley Periodicals, Inc.

Determining non-cigarette tobacco, alcohol, and substance use typologies across menthol and non-menthol smokers using latent class analysis

Background

Substance use and mental health are robustly associated with smoking and poor cessation outcomes, but not often examined in combination with menthol cigarette smoking, which is also associated with lower quit rates. This study identified classes of Black and White menthol and non-menthol cigarette smokers based on demographics, alcohol, drug, and other tobacco use behaviors.

Methods

Using screening data from two studies, latent class analysis (LCA) was conducted to classify n = 1177 menthol and non-menthol cigarette smokers on demographic characteristics, heavy smoking, alcohol and drug use, desire to quit smoking, other tobacco product use, and use of psychotropic medication.

Results

Three latent classes were identified that differentiated smokers on substance use, menthol cigarette smoking, and other tobacco use behavior. One class consisted primarily of young adults who used a wide array of other tobacco products, reported the highest prevalence of other drug use, and showed the lowest desire to quit smoking cigarettes in the next 6-months. Class 2 comprised primarily of Black male menthol smokers, all of whom used cigarillos in addition to cigarettes, and who displayed moderate drug use. The third class was categorized as primarily older cigarette smokers, who engaged in very little other tobacco use or drug use, but who were most likely to self-report being prescribed psychotropic medication.

Conclusions

LCA allowed for the identification of distinct classes of smokers based on factors related to poor cessation outcomes, including menthol use, that have not previously been examined in combination. Interventions should target specific groups of smokers, rather than take a “one size fits all” approach.

Menthol Smokers: Metabolomic Profiling and Smoking Behavior

BACKGROUND

The use of menthol in cigarettes and marketing is under consideration for regulation by the FDA. However, the effects of menthol on smoking behavior and carcinogen exposure have been inconclusive. We previously reported metabolomic profiling for cigarette smokers, and novelly identified a menthol-glucuronide (MG) as the most significant metabolite directly related to smoking. Here, MG is studied in relation to smoking behavior and metabolomic profiles.

METHODS

This is a cross-sectional study of 105 smokers who smoked two cigarettes in the laboratory one hour apart. Blood nicotine, MG, and exhaled carbon monoxide (CO) boosts were determined (the difference before and after smoking). Spearman correlation, χ2, and ANCOVA adjusted for gender, race, and cotinine levels for menthol smokers assessed the relationship of MG boost, smoking behavior, and metabolic profiles. Multivariate metabolite characterization using supervised partial least squares-discriminant analysis (PLS-DA) was carried out for the classification of metabolomics profiles.

RESULTS

MG boost was positively correlated with CO boost, nicotine boost, average puff volume, puff duration, and total smoke exposure. Classification using PLS-DA, MG was the top metabolite discriminating metabolome of menthol versus nonmenthol smokers. Among menthol smokers, 42 metabolites were significantly correlated with MG boost, which linked to cellular functions, such as of cell death, survival, and movement.

CONCLUSIONS

Plasma MG boost is a new smoking behavior biomarker that may provide novel information over self-reported use of menthol cigarettes by integrating different smoking measures for understanding smoking behavior and harm of menthol cigarettes.

IMPACT

These results provide insight into the biological effect of menthol smoking. Cancer Epidemiol Biomarkers Prev; 26(1); 51-60. ©2016 AACR.

Flavour preferences in youth versus adults: a review

OBJECTIVE

To understand the available evidence of how children and adults differ in their preferences for flavours that may be used in tobacco products.

DATA SOURCES

A total of 474 articles published between 1931 and August 2015 were retrieved through searches conducted in PubMed, EMBASE, Web of Science and PsycINFO.

STUDY SELECTION AND EXTRACTION

A 2-phase relevancy review process resulted in the identification of 59 articles and information was extracted by 2 independent reviewers.

DATA SYNTHESIS

Findings were grouped by taste and smell preferences, which are important components of overall flavour. For taste, evidence is summarised in the following categories: sweet, salty, sour, bitter, umami and fat; within each of them, findings are organised by age categories. For smell, evidence is summarised as follows: fruit/herbal/spices, tobacco and coffee and other odours. Major findings from this search indicated that sweet preference in children and adolescents was higher than in adults. Examples of preferred food-related tastes and odours for young people included cherry, candy, strawberry, orange, apple and cinnamon. Currently, all these are used to flavour cigars, cartridges for electronic cigarettes, hookah (waterpipe) and smokeless tobacco products.

CONCLUSIONS

Infants and children exhibited elevated sweet and salty preference relative to adults. Age-related changes in bitter, sour, umami and fat taste were not clear and more research would be useful. 'Sweet' food odours were highly preferred by children. Tobacco products in flavours preferred by young people may impact tobacco use and initiation, while flavours preferred by adults may impact product switching or dual use.

Role of sweet and other flavours in liking and disliking of electronic cigarettes

OBJECTIVE

To examine the extent to which the perception of sweet and other flavours is associated with liking and disliking of flavoured electronic cigarettes (e-cigarettes).

METHODS

31 participants (13 females/18 males; 12 sole/19 dual users) vaped 6 commercially available flavours of blu Tanks: Classic Tobacco (CT), Magnificent Menthol (MM), Cherry Crush (CC), Vivid Vanilla (VV), Piña Colada (PC) and Peach Schnapps (PS); all 'medium' strength, 12 mg/mL nicotine concentration. For each flavoured e-cigarette, participants first rated liking/disliking on the Labeled Hedonic Scale, followed by perceived intensities of sweetness, coolness, bitterness, harshness and specific flavour on the generalised version of the Labeled Magnitude Scale. The psychophysical testing was conducted individually in an environmental chamber.

RESULTS

PC was perceived as sweetest and liked the most; CT was perceived as least sweet and liked the least. Across all flavours, liking was correlated with sweetness (r=0.31), coolness (r=0.25), bitterness (r=-0.25) and harshness (r=-0.29, all p<0.001). Specifically, liking was positively correlated with sweetness of PS (r=0.56, p=0.001) and PC (r=0.36, p=0.048); and with coolness of MM, CT and VV (r=0.41-0.52, p<0.05). In contrast, harshness was negatively correlated with liking for CC, PC and PS (r=0.37-0.40, p<0.05). In a multivariate model, sweetness had the greatest positive impact on liking followed by coolness; harshness had the greatest negative impact on liking.

CONCLUSIONS

Our findings indicate that bitterness and harshness, most likely from nicotine, have negative impacts on the liking of e-cigarettes, but the addition of flavourants that elicit sweetness or coolness generally improves liking. The results suggest that flavours play an important role in e-cigarette preference and most likely use.

Sensory Effects of Menthol and Nicotine in an E-Cigarette

INTRODUCTION

Despite the longstanding use and popularity of menthol as a flavorant in tobacco products, its sensory interactions with inhaled nicotine have never been measured independently of the other irritants in tobacco smoke. We therefore measured the perception of menthol in an E-cigarette with the primary goal of assessing its analgesic effect on the sensory irritation produced by inhaled nicotine.

METHODS

Adult cigarette smokers sampled aerosolized E-liquids containing five different concentrations of nicotine with 0%, 0.5%, or 3.5% l-menthol, as well as two commercial menthol flavors with and without nicotine. For each of the E-liquids participants used a labeled magnitude scale to rate the Overall Sensation intensity, Coolness/Cold, and Irritation/Harshness they experienced, and a Labeled Hedonic Scale to indicate how much they liked/disliked the overall flavor.

RESULTS

The main findings were that (1) perceived Irritation/Harshness was unaffected by a low (0.5%) menthol concentration, whereas a high menthol concentration (3.5%) led to higher perceived Irritation/Harshness at low nicotine concentrations but to lower Irritation/Harshness at the highest nicotine concentration (24mg/ml); (2) a commercial Menthol-Mint flavor produced similar results; (3) nicotine tended to enhance rather than suppress sensations of Coolness/Cold; and (4) menthol tended to slightly increase liking independently of nicotine concentration.

CONCLUSION

In addition to adding a sensation of coolness, menthol can reduce perceived airway irritation and harshness produced by inhalation when nicotine concentration is high, and contributes to the sensory impact of E-liquids when nicotine concentration is low.

IMPLICATIONS

The evidence presented here indicates that menthol can potentially improve the appeal of E-cigarettes not only via its coolness and minty flavor, but also by reducing the harshness from high concentrations of nicotine. As the first direct demonstration of an analgesic effect of menthol on inhaled nicotine in humans, these data also have implications for the role of menthol flavors in other inhaled tobacco products.

The Influence of Puff Characteristics, Nicotine Dependence, and Rate of Nicotine Metabolism on Daily Nicotine Exposure in African American Smokers

BACKGROUND

African American (AA) smokers experience greater tobacco-related disease burden than Whites, despite smoking fewer cigarettes per day (CPD). Understanding factors that influence daily nicotine intake in AA smokers is an important step toward decreasing tobacco-related health disparities. One factor of interest is smoking topography, or the study of puffing behavior.

AIMS

(i) to create a model using puff characteristics, nicotine dependence, and nicotine metabolism to predict daily nicotine exposure, and (ii) to compare puff characteristics and nicotine intake from two cigarettes smoked at different times to ensure the reliability of the puff characteristics included in our model.

METHODS

Sixty AA smokers smoked their preferred brand of cigarette at two time points through a topography device. Plasma nicotine, expired CO, and changes in subjective measures were measured before and after each cigarette. Total nicotine equivalents (TNE) was measured from 24-hour urine collected during ad libitum smoking.

RESULTS

In a model predicting daily nicotine exposure, total puff volume, CPD, sex, and menthol status were significant predictors (R(2) = 0.44, P < 0.001). Total puff volume was significantly greater and inter-puff intervals were significantly shorter after ad lib smoking compared with the first cigarette of the day, but puffing behaviors for both cigarettes were highly correlated (r range = 0.69-0.89, P < 0.001) within-subjects.

CONCLUSION

This is the first study, to our knowledge, to show that puff characteristics of individual cigarettes are predictive of daily nicotine intake.

IMPACT

These findings enhance our understanding of the relationship between smoking behavior and nicotine intake in AA smokers. Cancer Epidemiol Biomarkers Prev; 25(6); 936-43. ©2016 AACR.

Smoking Through a Topography Device Diminishes Some of the Acute Rewarding Effects of Smoking

BACKGROUND

Smoking topography (ST) devices are an important methodological tool for quantifying puffing behavior (eg, puff volume, puff velocity) as well as identifying puffing differences across individuals and situations. Available ST devices are designed such that the smoker's mouth and hands have direct contact with the device rather than the cigarette itself. Given the importance of the sensorimotor aspects of cigarette smoking in smoking reward, it is possible that ST devices may interfere with the acute rewarding effects of smoking. Despite the methodological importance of this issue, few studies have directly compared subjective reactions to smoking through a topography device to naturalistic smoking.

METHODS

Smokers (N = 58; 38% female) smoked their preferred brand of cigarettes one time through a portable topography device and one time naturalistically, in counterbalanced order across two laboratory sessions. Smoking behavior (eg, number of puffs) and subjective effects (eg, urge reduction, affect, smoking satisfaction) were assessed.

RESULTS

Negative affect reduction was greater in the natural smoking condition relative to the topography condition, but differences were not significant on measures of urge, withdrawal, or positive affect. Self-reported smoking satisfaction, enjoyment of respiratory tract sensations, psychological reward, craving reduction, and other rewarding effects of smoking were also significantly greater in the naturalistic smoking condition.

CONCLUSIONS

The effects of using a ST device on the smoking experience should be considered when it is used in research as it may diminish some of the rewarding effects of smoking.

IMPLICATIONS

When considering the inclusion of a smoking topography device in one's research, it is important to know if use of that device will alter the smoker's experience. This study assessed affective and subjective reactions to smoking through a topography device compared to naturalistic smoking. We found that smoking satisfaction, psychological reward, enjoyment of respiratory tract sensations and other rewarding effects were all diminished when smoking through the topography device. The effects of using a smoking topography device on the smoking experience should be considered when it is used in future research.

Menthol facilitates the intravenous self-administration of nicotine in rats

Menthol is preferred by ~25% of smokers and is the most common flavoring additive in tobacco and electronic cigarettes. Although some clinical studies have suggested that menthol facilitates the initiation of smoking and enhances the dependence on nicotine, many controversies remain. Using licking as the operant behavior, we found that adolescent rats self-administering nicotine (30μg/kg/infusion, free base, i.v.) with contingent oral menthol (60μl, 0.01% w/v) obtained significantly more infusions than rats receiving a vehicle cue or rats self-administering i.v. saline with a menthol cue. Rats yoked to their menthol-nicotine masters emitted significantly fewer licks on the active spouts, indicating that contingent pairing between nicotine and menthol is required for sustained nicotine intake. Rats that self-administered nicotine with a menthol cue also exhibited a long-lasting extinction burst and robust reinstatement behavior, neither of which were observed in rats that self-administered saline with a menthol cue. The cooling sensation of menthol is induced by activating the transient receptor potential M8 (TRPM8) channel. When WS-23, an odorless agonist of the TRPM8 channel, was used as a contingent cue for nicotine, the rats obtained a similar number of nicotine infusions as the rats that were provided a menthol cue and exhibited a strong preference for the active spout. In contrast, highly appetitive taste and odor cues failed to support nicotine self-administration. These data indicated that menthol, likely by inducing a cooling sensation, becomes a potent conditioned reinforcer when it is contingently delivered with nicotine. Together, these results provide a key behavioral mechanism by which menthol promotes the use of tobacco products or electronic cigarettes.

Menthol-enhanced cytotoxicity of cigarette smoke demonstrated in two bioassay models

Background

Cigarette smoke is harmful to human health at both cellular and genetic levels. Recently, a unique bioassay for smoke cytotoxicity using air pollution-sensitive plant cells (tobacco) has been proposed.

Methods

Model plant cells (tobacco Bel-W3 cells) and human cells (alveolar epithelial A549 cells) suspended in fresh culture media were exposed to cigarette smoke sampled after lighting the tip of cigarettes (with vs. without menthol capsules) which were attached to a glass pipe connected to the cell-containing plastic tubes. Control cultures were also assessed.

Results

After exposing tobacco plant cells to cigarette smoke, cell death occurred in a dose-dependent manner. Cell death was significantly enhanced by mentholated smoke, while menthol alone was shown to be inert suggesting that menthol synergistically contributes to the enhancement of cell death, initiated by smoke-associated compounds. The enhanced toxicity of mentholated smoke was confirmed in human alveolar epithelial A549 cells.

Conclusions

Cigarette smoke cytotoxicity leading to cell death assessed in plant and human model cells was enhanced by menthol. Further research into these findings is encouraged.

Menthol cigarettes, race/ethnicity, and biomarkers of tobacco use in U.S. adults: the 1999-2010 National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

In the United States, cigarette flavorings are banned, with the exception of menthol. The cooling effects of menthol could facilitate the absorption of tobacco toxicants. We examined levels of biomarkers of tobacco exposure among U.S. smokers of menthol and nonmenthol cigarettes.

METHODS

We studied 4,603 White, African-American, and Mexican-American current smokers 20 years of age or older who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2010 and had data on cigarette type and serum cotinine, blood cadmium, and blood lead concentrations. Urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) (NNAL) was studied in 1,607 participants with available measures.

RESULTS

A total of 3,210 (74.3%) participants smoked nonmenthol cigarettes compared with 1,393 (25.7%) participants who smoked menthol cigarettes. The geometric mean concentrations comparing smokers of nonmenthol with menthol cigarettes were 163.1 versus 175.9 ng/mL for serum cotinine; 0.95 versus 1.02 μg/L for blood cadmium; 1.87 versus 1.75 μg/dL for blood lead; and 0.27 versus 0.23 ng/mL for urine NNAL. After multivariable adjustment, the ratios [95% confidence interval (CI)] comparing smokers of menthol with nonmenthol cigarettes were 1.03 (0.95-1.11) for cotinine, 1.10 (1.04-1.16) for cadmium, 0.95 (0.90-1.01) for lead, and 0.81 (0.65-1.01) for NNAL.

CONCLUSIONS

In a representative sample of U.S. adult smokers, current menthol cigarette use was associated with increased concentration of blood cadmium, an established carcinogen and highly toxic metal, but not with other biomarkers.

IMPACT

These findings provide information regarding possible differences in exposure to toxic constituents among menthol cigarette smokers compared with nonmenthol cigarette smokers.

A cross-sectional study on tobacco use and dependence among women: Does menthol matter?

BACKGROUND

The question of whether mentholation of cigarettes enhances tobacco dependence has generated conflicting findings. Potential mediating factors in a putative relationship between menthol use and tobacco dependence may include race and gender. While an association between menthol use and dependence is mixed, research on the role of race solely among women smokers is scarce. This study examined whether women menthol smokers have higher tobacco use and dependence than non-menthol smokers. Further, the study investigated differences between White and African American smokers.

METHODS

A cross-sectional study was conducted among 928 women seeking tobacco dependence treatment in Boston, Massachusetts. Measures obtained included preferred brand and menthol content, dependence markers (cigarettes per day (CPD); time to first cigarette in the morning; number of and longest previous quit attempts) and smoking history (age of initiation; years smoking; menthol or non-menthol cigarette preference). Analysis of variance (ANOVA) was used to detect interactions between menthol preference by race for continuous variables, and Pearson's chi-squared test was used for analyses with dichotomous variables.

RESULTS

A greater proportion of menthol smokers smoked their first cigarette within five minutes of waking (p < 0.01) and were less likely to have a previous quit attempt longer than 90 days (p < 0.01). ANOVAs revealed no main effects for menthol preferences. However, African American smokers smoked fewer CPD (p<.001), started smoking later in life (p= .04), and had been smoking the same brand for longer (p= .04).

CONCLUSIONS

Women menthol smokers showed signs of greater tobacco dependence than non-menthol smokers. African Americans smoked fewer CPD but nevertheless had evidence of greater dependence.

Menthol attenuates respiratory irritation responses to multiple cigarette smoke irritants

Menthol, the cooling agent in peppermint, is added to almost all commercially available cigarettes. Menthol stimulates olfactory sensations, and interacts with transient receptor potential melastatin 8 (TRPM8) ion channels in cold-sensitive sensory neurons, and transient receptor potential ankyrin 1 (TRPA1), an irritant-sensing channel. It is highly controversial whether menthol in cigarette smoke exerts pharmacological actions affecting smoking behavior. Using plethysmography, we investigated the effects of menthol on the respiratory sensory irritation response in mice elicited by smoke irritants (acrolein, acetic acid, and cyclohexanone). Menthol, at a concentration (16 ppm) lower than in smoke of mentholated cigarettes, immediately abolished the irritation response to acrolein, an agonist of TRPA1, as did eucalyptol (460 ppm), another TRPM8 agonist. Menthol's effects were reversed by a TRPM8 antagonist, AMTB. Menthol's effects were not specific to acrolein, as menthol also attenuated irritation responses to acetic acid, and cyclohexanone, an agonist of the capsaicin receptor, TRPV1. Menthol was efficiently absorbed in the respiratory tract, reaching local concentrations sufficient for activation of sensory TRP channels. These experiments demonstrate that menthol and eucalyptol, through activation of TRPM8, act as potent counterirritants against a broad spectrum of smoke constituents. Through suppression of respiratory irritation, menthol may facilitate smoke inhalation and promote nicotine addiction and smoking-related morbidities.