Sensory and physiologic effects of menthol and non-menthol cigarettes with differing nicotine delivery

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.

Pod-based e-cigarettes versus combustible cigarettes: The impact on peripheral and cerebral vascular function and subjective experiences

INTRODUCTION

The vaping epidemic in the US has been largely attributed to the emergence of pod-based e-cigarette devices. While these devices continue to be promoted as alternatives to cigarettes, their impact on cardiovascular and behavioral outcomes remains incompletely understood. This study assessed the impact of pod-based e-cigarettes on peripheral and cerebral vascular function, along with subjective experiences among adult cigarette smokers.

METHODS

In a crossover laboratory design study, a total of 19 (e-cigarette naïve) cigarette smokers (aged 21-43 years) attended two lab sessions. In one session, participants smoked a cigarette and in the other, vaped a pod-based e-cigarette. Participants completed questions assessing subjective experiences. Peripheral macrovascular and microvascular function was assessed via brachial artery FMD and reactive hyperemia, while cerebral vascular function was assessed as the blood velocity response of the middle cerebral artery during hypercapnia. Measurements were taken before and after exposure.

RESULTS

Compared with baseline, there was a reduction in peripheral macrovascular function (indexed by FMD), following e-cigarette (pre=9.3±4.3%; post=6.4±4.1%) and cigarette use (pre=10.2±3.7%; post=6.8±3.8%; main effect of time p<0.0001). Cerebral vascular function (indexed by cerebral vasodilatory response during hypercapnia) was also reduced following e-cigarette (pre=53±19%; post=44±15%) and cigarette use (pre=54±21%; post=44±17%; main effect of time p<0.01). The magnitude of reduction in peripheral and cerebral vascular function was similar between conditions (condition × time, p>0.05). Compared with vaping an e-cigarette, participants scored higher for measures of satisfaction, taste, puff liking, and suppression of craving following smoking (p>0.05).

CONCLUSIONS

Similar to smoking, vaping a pod-based e-cigarette leads to an impairment in peripheral and cerebral vascular function while providing a reduced subjective experience compared with a cigarette among adult smokers. While these data challenge the notion that e-cigarette use is a safe and satisfactory alternative to cigarette use, large longitudinal studies are needed to assess the long-term impact of pod-based e-cigarette devices on cardiovascular and behavioral outcomes.

A Method to Amend Cigarettes With Menthol for Use in Research

INTRODUCTION

Studies have evaluated the role of menthol cigarettes on various addiction-related outcomes; however, the effect of varying menthol content on these outcomes has not been evaluated. We developed a method to amend non-menthol SPECTRUM Research Cigarettes to contain menthol at four different levels.

AIMS AND METHODS

SPECTRUM Research Cigarettes, NRC 600 (0.8 mg nicotine; 10 mg tar), were modified to contain target menthol amounts at 3, 6, and 12 mg/cigarette by injecting 25 µL ethanol/triacetin/menthol solutions of varying concentrations (120 mg menthol/mL, 240 mg/mL, and 480 mg/mL) into four distinct locations in the filter and tobacco rod. Menthol content was tested in triplicate in the whole cigarette and in the tobacco rod and filter at 1, 24, 48, and 72 hours for each target menthol level using an extraction solution of quinoline in methyl-tert-butyl ether and measured using gas chromatography with flame ionization detection.

RESULTS

Injections into the filter and tobacco rod (12.5 µL each) yielded equal menthol distribution up to 72 hours. However, total menthol content decreased from an average of 90.3% of the target menthol concentration at 1 hour to 80.7% at 72 hours in cigarettes stored individually in glass tubes at room temperature. Analysis of urinary menthol glucuronide confirmed that amended cigarettes used within 24 hours of injection delivered dose-related menthol levels to participants in a clinical laboratory setting.

CONCLUSION

This method can be used to modify cigarettes with a range of reliable menthol levels in both filter and tobacco rod for use in laboratory and clinical research.

IMPLICATIONS

This study presents a technique for modifying cigarettes with different levels of menthol that can reliably deliver dose-related menthol levels to participants when smoked in a clinical study. The technique can be used to quickly amend cigarettes to examine the independent effects of varying flavor and additive levels on smoking behavior, nicotine pharmacokinetics, mainstream smoke emissions, and other laboratory or clinical research outcomes.

The Effects of Pictorial Health Warning Label on Waterpipe (Low- and High-Frequency) Smokers' Experiences, Toxicant Exposures, and Puffing Behavior

BACKGROUND

Pictorial health warning label (PHWL) is an effective risk communication measure among cigarette smokers. However, there is a lack of knowledge regarding the effect of PHWL on low- and high-frequency waterpipe (WP) smokers. This study examined the effects of PHWL on puffing behavior, subjective experiences, and toxicant exposures among low- and high-frequency WP smokers in the United States (US).

METHODS

Sixty current (past-month) WP smokers (low-frequency; n = 30 and high-frequency; n = 30) completed two 45-min ad libitum WP smoking sessions in a cross-over design study (WP with no-PHWL vs. WP with PHWL). We compared the mean differences of puff topography, expired carbon monoxide (eCO), plasma nicotine concentration, and subjective experiences between the two smoking groups.

RESULTS

Mean age of low-frequency smokers was 21.5 years and high-frequency smokers was 21.3 years. Compared to high-frequency, low-frequency smokers had significant reduction in average total smoking time [mean difference (SD) =  -7.6 (10.2) min vs. -2.6 (6.7) min, p = 0.03] and number of puffs [mean difference (SD) =  -33.37 (70.7) vs. -0.70 (29.2), p = 0.02] following exposure to PHWL compared to no-PHWL condition. Post-session subjective experiences were lower among high-frequency smokers compared to low-frequency smokers following smoking WP with PHWL compared to the no-PHWL session (puff liking -1.2 vs. -0.5; puff satisfaction -1.0 vs. -0.3; craving reduction -0.5 vs. 1.2) (p < 0.05 for all).

CONCLUSION

Our findings indicate that placing PHWL on the WP device may be a promising strategy with differential effectiveness among WP smokers: low-frequency (reduce puffing behaviors) and high-frequency (reduce smoking experience).

Effect of menthol/mint-flavored pods on young JUUL E-cigarette users' subjective experience, puffing behavior, and nicotine exposure: A pilot study

BACKGROUND

Recent regulations have banned all flavors except menthol/mint and classic tobacco from pod-based e-cigarette devices such as JUUL. However, menthol/mint flavor can present a potential risk given its increasing popularity among young people in the US and its puffing and nicotine-enhancing properties. This study examines the impact of menthol/mint flavor manipulation on users' puffing behavior, subjective experience, and nicotine exposure among young people.

METHODS

JUUL users (n = 33, 18-24 years) attended two 60-min ad libitum e-cigarette use sessions (menthol/mint flavor vs. classic tobacco flavor) in a cross-over design. Puff topography and plasma nicotine concentration were measured, and participants completed subjective experience questionnaires.

RESULTS

Following the use of the menthol/mint-flavored pod, increases were observed in measures of satisfaction, pleasurable/interest to use, willingness to use again, enjoyment, urge to vape, product appeal, taste, and concentration (p < .05 for all). For example, compared to the classic tobacco flavor, participants experienced significantly more satisfaction of the product (4.24 vs. 3.09; p = .001) and sensation enjoyment of the product (3.55 vs. 2.48; p = .002) when using the menthol/mint flavor. While means of the plasma nicotine boost and puff parameters were lower in the classic tobacco condition compared to the menthol/mint flavor condition, no statistical significance was observed between the two conditions (p > .05 for all).

CONCLUSIONS

Results of this pilot study suggest that menthol/mint-flavor increases e-cigarette users' subjective experience significantly. Regulating menthol/mint flavor is a potentially promising strategy to curb e-cigarette use among young people.

Measuring young adult appeal for menthol and non-menthol cigarettes: protocol of a clinical trial using both laboratory and intensive longitudinal methods (PRISM)

INTRODUCTION

Although the Food and Drug Administration banned other characterising flavours in cigarettes, menthol cigarettes are still available to consumers. Young adult new smokers are initiating with menthol cigarettes, such that the prevalence of young adults menthol versus non-menthol smokers is increasing. Experimentation with menthol cigarettes is associated with progression to regular smoking and nicotine dependence. This ongoing clinical trial in young adult smokers measures appeal and the reinforcing value of smoking menthol versus non-menthol cigarettes and the impact of these variables on changes in smoking behaviour at a 6-month follow-up.

METHODS AND ANALYSIS

Reinforcement for menthol smoking is assessed in the laboratory using a validated behavioural economic choice task, and appeal is measured in the natural environment using ecological momentary assessment (EMA). Analyses will examine differences between menthol and non-menthol cigarette smoking on measures of subjective response in the laboratory and via EMA, and how subjective response mediates the association between menthol preference at baseline and smoking outcomes at follow-up.

ETHICS AND DISSEMINATION

This protocol was approved by the University of Oklahoma Health Sciences Center Institutional Review Board (#10581). The findings will isolate the unique effects of menthol in smoking and will help inform regulatory decisions about the abuse liability of menthol cigarettes. Findings will be disseminated through peer-reviewed journal articles and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

NCT03953508.

Plasma Menthol Glucuronide as a Biomarker for the Behavioral Effects of Menthol and Nicotine in Humans

This secondary analysis sought to determine if plasma menthol glucuronide (MG) concentrations predict changes in three outcomes, subjective drug effects, urges to smoke, and heart rate, following concurrent inhaled menthol and intravenous nicotine. A total of 45 menthol and non-menthol cigarettes smokers (36 male, nine female, 20 Black, and 23 White) were included in this double-blind, placebo-controlled study. Across three test sessions, participants were assigned to a different flavor condition for each session: 0% (no menthol), 0.5%, or 3.2% menthol. In each test session, participants received in a random order one intravenous delivery of saline and two intravenous deliveries of nicotine (0.25 mg/70 kg and 0.5 mg/70 kg), each 1 h apart, concurrent with menthol delivery by e-cigarettes. The main outcomes were subjective drug effects, urges to smoke, and heart rate. The results showed that following e-cigarette inhalation, changes in plasma MG concentrations or “menthol boost” increased proportionally to the menthol concentration in the e-liquids. While changes in plasma MG concentrations were not predictive of increases in heart rate or subjective drug effects that are reflective of acute effects from nicotine (i.e., feel good effects, stimulated, aversive effects), they were predictive of cooling effect, a typical effect of menthol, but only in menthol smokers in the absence of concurrent active nicotine infusion. These findings demonstrate the utility of plasma MG as a biomarker both for acute menthol exposure by e-cigarette inhalation and for the examination of the concentration-dependent behavioral and physiological effects of menthol in humans.

Affirming the Abuse Liability and Addiction Potential of Menthol: Differences in Subjective Appeal to Smoking Menthol Versus Non-Menthol Cigarettes Across African American and White Young Adult Smokers

INTRODUCTION

Menthol cigarettes are popular among young adults and are disproportionately used by African American smokers. Menthol's minty and cooling sensations have been hypothesized to enhance the appeal and reinforcement of smoking; however, differences in menthol's subjective appeal across races have been inconsistent. This secondary data analysis examined differences in subjective appeal for smoking menthol versus non-menthol cigarettes between African American and White young adult smokers.

METHODS

Young adults (ages 18-24) recruited from Amazon Mechanical Turk (December 2018-January 2019) completed an online survey of tobacco use behavior. Past year smokers (n = 1726) answered questions about subjective responses to smoking (reward, satisfaction, throat hit, craving reduction, and aversion).

RESULTS

Significantly more African American (73.2%) compared to White (52.4%) smokers preferred menthol cigarettes (p < .001). Menthol smokers reported greater positive and negative subjective responses to smoking than non-menthol smokers. Positive and negative subjective response were both associated with greater smoking intensity and lower cigarette harm perceptions. Interactions of menthol preference and race on indices of subjective appeal also emerged. African American non-menthol smokers reported lower levels of satisfaction, reward, and craving reduction compared to White non-menthol smokers.

CONCLUSIONS

The relationship between menthol preference and subjective response to smoking differs by race. Menthol is rated as more appealing than non-menthol smoking, and appeal indices were linked to smoking intensity and lower harm perceptions, indicating greater abuse liability of menthol cigarettes. Policies that ban menthol cigarettes may have a particularly positive impact on the cigarette smoking of African American young adult smokers.

IMPLICATIONS

The FDA issued an Advanced Notice of Proposed Rule Making to examine the role menthol in tobacco products to inform regulations to restrict or ban flavors. This study showed that menthol smokers reported greater appeal to smoking than non-menthol smokers; and an interaction of race x menthol preference showed African American non-menthol smokers reported the lowest levels of appeal to smoking. Multiple indices of cigarette appeal were positively correlated with smoking intensity and lower cigarette harm perceptions, highlighting the addiction potential of menthol cigarettes. Findings suggest a menthol cigarette ban could help reduce tobacco use among young adults.

Differences in Smoking Topography and Subjective Responses to Smoking Among African American and White Menthol and Non-Menthol Smokers

INTRODUCTION

It has been suggested that menthol increases exposure to harmful elements of smoking and makes smoking more rewarding, easier to initiate, and harder to quit. Isolating the direct effects of menthol is challenging as African American (AA) race and menthol preference are highly overlapping. This study evaluated smoking behavior and subjective responses among a balanced sample of AA and white menthol and non-menthol smokers. In addition, smoking topography (ST) was compared to naturalistic smoking (NS) and interactions with menthol and race were explored.

AIMS AND METHODS

Smokers (N = 100) smoked and rated their preferred brand of cigarettes via ST or NS during two laboratory visits (counterbalanced).

RESULTS

Controlling for baseline differences among the groups (eg, nicotine dependence), menthol smokers took shorter and smaller puffs and AA smokers took longer puffs, but there were no differences in total puff volume, carbon monoxide, or other ST parameters. Menthol smokers reported greater urge reduction and lower sensory stimulation. The smoking method (ST vs. NS) had no effects on smoking behavior or exposure. Cigarettes smoked via ST were rated stronger. Differences in satisfaction based on the smoking method interacted with race and menthol status. Ratings of aversion differed by race and menthol status.

CONCLUSIONS

Menthol was not associated with increased smoke exposure or reward (except for urge reduction). ST caused minimal experimental reactivity relative to NS. Additional research that isolates the effects of menthol and examines potential interactive effects with race and other variables is needed to better understand its role in smoking-related health disparities.

IMPLICATIONS

Menthol and non-menthol smokers differed on some demographic variables and menthol preference was associated with greater nicotine dependence and greater urge reduction after smoking. Menthol was not associated with greater smoke exposure. Future research that investigates the unique risks associated with menthol and examines potential interactive effects with race and other related variables is warranted to better understand the role of menthol in smoking-related health disparities.

Effect of flavour manipulation on ENDS (JUUL) users' experiences, puffing behaviour and nicotine exposure among US college students

SIGNIFICANCE

Electronic nicotine delivery system (ENDS) use has continued to increase exponentially among young people in the USA, with unique flavours being one of the most cited reasons for use. Yet, controlled studies examining the effects of restricting flavour are lacking. This study evaluates the impact of ENDS flavour manipulation on user's puffing behaviour, subjective experience, harm perception and nicotine exposure among college-aged ENDS users.

METHODS

JUUL users (n=30, age 18 to 24 years) attended two 60 min ad libitum ENDS use sessions (JUUL preferred flavour vs JUUL classic tobacco flavour) in a cross-over design. Puff topography and plasma nicotine concentration were measured, and participants completed subjective experience questionnaires.

RESULTS

Increases were observed on measures of satisfaction, taste, enjoyment, urges to vape/smoke, pleasure, product appeal and increased concentration following using the preferred flavour pod (p values <0.05). Compared with preferred flavour, participants in the tobacco flavour were less motivated to use it in the future (70.9 vs 19.1 scores, p<0.001), even if it was the only product on the market (75.8 vs 30.7 scores, p<0.001). While nicotine levels significantly increased in both conditions from pre to post session (p values <0.001), no significant differences were observed in nicotine boost levels or on puff topography parameters when comparing both flavour conditions.

CONCLUSIONS

This pilot study provides evidence that ENDS flavours have a substantial effect in enhancing young current ENDS users' experiences, product appeal and motivation to use the product in the future. It highlights that limiting flavours could play a potential role when designing strategic policies to reduce the appeal of ENDS use among young people.

Flavored Versus Nonflavored Waterpipe Tobacco: A Comparison of Toxicant Exposure, Puff Topography, Subjective Experiences, and Harm Perceptions

INTRODUCTION

Flavored waterpipe (WP) tobacco is the main type of tobacco used by young WP smokers, and a major factor attracting youth to smoke. However, evidence regarding the effect of limiting flavor on WP smokers' experience continues to be lacking. This study aims at evaluating the effect of flavor restriction on WP smokers' toxicant exposure, smoking topography, subjective experiences and harm perception.

METHODS

Thirty-two WP smokers completed two, 45-minute ad libitum smoking sessions (preferred flavor vs non-flavored tobacco) in a crossover design pilot study. Plasma nicotine concentration and exhaled carbon monoxide (eCO) were measured before and after each smoking session. Puff topography was recorded throughout the smoking session. Participants completed survey questionnaires assessing subjective smoking experiences and harm perception.

RESULTS

Significant differences were observed in plasma nicotine concentration between the two WP tobacco conditions, with a higher increase in plasma nicotine concentration following the flavored tobacco session. There were no significant differences between the two WP tobacco conditions for eCO and smoking topography measures. Compared with the non-flavored WP tobacco, we documented enhanced subjective smoking measures of satisfaction, calmness, taste, puff liking and enjoyment following the preferred flavored WP tobacco session. Cigarette harm perception was significantly higher among participants after smoking their preferred flavor compared with non-flavored WP tobacco.

CONCLUSIONS

Limiting tobacco flavor has a substantial effect on WP smokers' nicotine exposure, subjective experience and harm perception. Therefore, eliminating or restricting WP flavors could be an essential element of comprehensive tobacco control policies to reduce the appeal of WP tobacco products for youth.

IMPLICATIONS

This study highlights the important role of flavor in shaping WP smokers' experiences and exposures and the potential impact that regulating flavored WP tobacco may have on curbing WP use among youth in the US. Such regulations may reduce the appeal and the interest in WP smoking initiation and continued use.

Menthol cigarette smoking is associated with greater subjective reward, satisfaction, and "throat hit", but not greater behavioral economic demand

AIMS

The cooling and minty flavor of menthol in cigarettes has been hypothesized to mask the harshness of inhaled cigarette smoke, contributing to menthol's appeal and subjective reinforcement and linking menthol use to smoking initiation, progression, nicotine dependence, and difficulty quitting. This study examined differences between menthol and non-menthol smokers on behavioral economic indices of reinforcing efficacy (i.e., demand) and subjective response to smoking (i.e., satisfaction, reward, "throat hit," aversion) and the association between measurements of reinforcement and subjective response.

DESIGN

600 current adult smokers were recruited from an online smoking cessation program. Following website enrollment, individuals completed a self-report measurement of subjective response to smoking (reward, satisfaction, aversion, "throat hit"), and a modified cigarette purchase task (CPT) to assess behavioral economic cigarette demand.

FINDINGS

In bivariate and adjusted ANOVA models, menthol smokers reported greater subjective reward, satisfaction, and positive sensations in the throat ("throat hit") from smoking compared to non-menthol smokers; and those outcomes were also correlated with greater nicotine dependence and lower likelihood of a past-year quit attempt. Although cigarette demand was associated with smoking level, subjective smoking reward, and nicotine dependence, there were no differences in smoking demand between menthol vs. non-menthol smokers.

CONCLUSIONS

The pleasurable aspects of menthol vs non-menthol smoking may be a mechanism linking it to greater nicotine dependence and difficulty quitting. A menthol ban could decrease population-level cigarette consumption by restricting smokers' access to a highly rewarding cigarette flavoring.

The effect of flavoured and non-flavoured tobacco on subjective experience, topography and toxicant exposure among waterpipe smokers

INTRODUCTION

Flavoured waterpipe (WP) tobacco is a major factor in the resurgence of WP smoking and a main attractant of WP use among youth. Yet, evidence of the effects of limiting flavour on WP smoker's experiences and exposures is limited. This study examined the impact of flavour manipulation on WP smokers' toxicant exposure and smoking experiences.

METHOD

A total of 144 WP smokers attended two, 45 min ad libitum smoking sessions (flavoured vs non-flavoured tobacco) in a crossover design study. Participants completed a battery of questions assessing subjective smoking experiences. Exhaled carbon monoxide (eCO) and plasma nicotine concentrations were measured before and after the smoking sessions. Puff topography was recorded throughout the smoking sessions.

RESULTS

Compared with the non-flavoured WP tobacco, participants reported enhanced subjective smoking measures of satisfaction and enjoyment following smoking flavoured WP tobacco (ps <0.05). Although participants spent a longer time smoking flavoured tobacco, they took on average larger puffs while smoking the non-flavoured tobacco (ps <0.05). Greater levels of eCO were recorded following the non-flavoured tobacco session (p<0.05) compared with flavoured tobacco. No significant differences were observed in plasma nicotine concentrations between the two tobacco conditions. WP harm perception was higher among participants after smoking non-flavoured WP tobacco compared with their preferred flavour (p<0.05).

CONCLUSION

Smoking the flavoured tobacco product was associated with enhanced subjective experiences compared with the non-flavoured, suggesting a potential role for flavour regulation in reducing WP use. Mixed results were observed for toxicants exposure in relation to smoking flavoured compared with non-flavoured products suggesting the need for a more comprehensive assessment of the effects of other tobacco constituents and additives on toxicant exposure in WP smokers.

Pictorial health warning labels on the waterpipe device are effective in reducing smoking satisfaction, puffing behaviour and exposure to CO: first evidence from a crossover clinical laboratory study

OBJECTIVES

This study examined the effect of pictorial health warning labels (HWLs) on the waterpipe (WP) device on smokers' experience, puffing behaviour, harm perception and exposure to respiratory toxicants.

METHODS

Thirty WP smokers completed two 45 min ad libitum smoking sessions (WP without HWL vs WP with HWL) in a crossover design study. Exhaled carbon monoxide (eCO) was measured before and after each smoking session. Puff topography was recorded throughout the smoking session, and participants completed survey questionnaires assessing subjective smoking experiences and harm perception.

RESULTS

Significant differences were observed in eCO levels between the two study conditions, with lower levels of eCO boost recorded following smoking the WP fitted with HWL (16 ppm) compared with WP without HWL (22.7 ppm). Participants had more puffs, shorter interpuff intervals and a higher total puff volume during smoking the WP without HWL relative to WP with HWL (p values <0.05). We documented enhanced reports of satisfaction, taste and puff liking following smoking the WP without HWL compared with the WP with HWL. WP harm perception was significantly higher among participants after smoking the WP with HWL compared with WP without HWL.

CONCLUSION

This pilot study shows that placing HWL on the WP device is effective in reducing WP smoker's positive experiences, puffing parameters and exposure to carbon monoxide. HWLs lead also to more appreciation of WP harmful effects, making them a promising regulatory approach for addressing the spread of WP smoking among young adults in the USA.

Preliminary validity of the modified Cigarette Evaluation Questionnaire in predicting the reinforcing effects of cigarettes that vary in nicotine content

Validity studies evaluating self-report measures in relation to behavioral preference of cigarettes varying in nicotine content are needed. The current study examined the relationship between ratings on the modified Cigarette Evaluation Questionnaire (mCEQ) and the relative reinforcing effects of Spectrum research cigarettes (15.8, 5.2, 2.4, 0.4 mg per gram of tobacco). Data for this secondary analysis were obtained from a double-blind study (Higgins et al., 2017) evaluating the subjective and reinforcing effects of Spectrum cigarettes under acute smoking abstinence. Current smokers (N = 26) were recruited from three vulnerable smoking populations (economically disadvantaged women of reproductive age, opioid-maintained individuals, individuals with affective disorders). In Phase 1 (five sessions), the mCEQ (Satisfaction, Psychological Reward, Enjoyment of Respiratory Tract Sensations, Craving Reduction, Aversion subscales) was administered following ad lib smoking of Spectrum cigarettes and subscale differences scores were calculated by subtracting ratings of the 15.8 mg/g cigarette from ratings of the reduced nicotine content cigarettes. In Phase 2 (six sessions), participants completed six 2-dose concurrent choice tests. The relationship between mCEQ subscale difference scores from Phase 1 and nicotine dose choice from Phase 2 was examined using mixed-model repeated-measures analyses of variance. Higher Satisfaction and lower Aversion subscale difference scores were associated with choosing the 15.8 mg/g cigarette more than the 5.2, 2.4, and 0.4 mg/g cigarettes. Scores on the other mCEQ subscales were not associated with nicotine choice. These results provide support for validity of the mCEQ Satisfaction and Aversion subscales predicting the relative reinforcing effects and abuse liability of varying nicotine content cigarettes. (PsycINFO Database Record

Threshold dose for behavioral discrimination of cigarette nicotine content in menthol vs. non-menthol smokers

RATIONALE

The lowest threshold content (or "dose") of nicotine discriminated in cigarettes may differ due to menthol preference.

OBJECTIVES

Menthol and non-menthol Spectrum research cigarettes differing in nicotine content were used to determine discrimination thresholds.

METHODS

Dependent smokers preferring menthol (n = 40) or non-menthol (n = 21) brands were tested on ability to discriminate cigarettes (matched for their menthol preference) with nicotine contents of 16-17, 11-12, 5, 2, and 1 mg/g, one per session, from an "ultra-low" cigarette with 0.4 mg/g. Controlled exposure to each cigarette was four puffs/trial, and the number of sessions was determined by the lowest nicotine content they could discriminate on >80% of trials (i.e., ≥5 of 6). We also assessed subjective perceptions and behavioral choice between cigarettes to relate them to discrimination responses.

RESULTS

Controlling for Fagerstrom Test of Nicotine Dependence score, discrimination thresholds were more likely to be at higher nicotine content cigarettes for menthol vs. non-menthol smokers (p < .005), with medians of 16 vs. 11 mg/g, respectively. Compared to the ultra-low, threshold and subthreshold (next lowest) cigarettes differed on most perceptions and puff choice, but menthol preference did not alter these associations. Notably, threshold cigarettes did, but subthreshold did not, increase choice over the ultra-low.

CONCLUSIONS

Threshold for discriminating nicotine via smoking may be generally higher for menthol vs. non-menthol smokers. More research is needed to identify why menthol smoking is related to higher nicotine thresholds and to verify that cigarettes unable to be discriminated do not support reinforcement.

Stroke risk among menthol versus non-menthol cigarette smokers in the United States: Analysis of the National Health and Nutrition Examination Survey (NHANES)

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

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.

Nicotine and carbon monoxide exposure from inhalation of cigarillo smoke

BACKGROUND

There has been an increase in the use of cigarillos in the US. People who smoke cigarillos typically also regularly smoke cigarettes (dual users).

METHODS

We compared puffing topography, biomarkers of acute exposure [exhaled carbon monoxide (COex) and plasma nicotine] and physiologic effects from usual brand cigarette and Black & Mild cigarillo smoking in dual users (N=23) in two laboratory sessions.

RESULTS

Participants (21 men) smoked an average of 17.5cigarettes/day. Cigarillo consumption varied widely from as few as 1/week to daily. Participants were highly nicotine dependent (average FTND score: 6.3). There were statistically significant differences in smoking behavior between cigarette and cigarillo smoking in time to smoke, number of puffs, and total puff volume (all P<0.001). Average puff duration, interpuff interval average puff volume, and puff velocity did not differ between cigarettes and cigarillos. Nicotine boost was similar after both cigarettes and cigarillos. COex boost was significantly greater after cigarillo smoking compared to cigarette smoking (P<0.001).

CONCLUSIONS

The smoking pattern and exposure profile indicate that dual users inhale cigarillo smoke just as they inhale cigarette smoke thereby exposing themselves to considerable amounts of nicotine and other components of tobacco smoke. COex exposure results imply that cigarillo smoking may be associated with higher exposure to smoke-delivered volatile components of mainstream cigarillo smoke including carcinogens when compared to cigarettes.

IMPACT

The findings that cigarillos and cigarettes are smoked similarly in dual users are relevant to health and regulatory considerations on cigar products.

Make your own cigarettes: toxicant exposure, smoking topography, and subjective effects

BACKGROUND

Despite considerable use of make your own (MYO) cigarettes worldwide and increasing use in the United States, relatively little is known about how these cigarettes are smoked and the resultant toxicant exposure.

METHODS

In a laboratory study, we compared two types of MYO cigarettes-roll your own (RYO) and personal machine made (PMM)-with factory-made (FM) cigarettes in three groups of smokers who exclusively used RYO (n = 34), PMM (n = 23), or FM (n = 20). Within each group, cigarettes were smoked in three conditions: (i) after confirmed overnight tobacco abstinence; (ii) in an intense smoking paradigm; and (iii) without restrictions. All cigarettes were smoked ad lib through a smoking topography unit.

RESULTS

Plasma nicotine significantly increased after cigarettes in all conditions except PMM in the intense smoking paradigm. Puff volume, puff duration, total puff volume, and puff velocity did not differ between cigarette types but the puffs per cigarette and time to smoke were significantly smaller for RYO compared with PMM and FM. Regardless of the cigarette, participants consumed the first three puffs more vigorously than the last three puffs.

CONCLUSIONS

Despite the belief of many of their consumers, smoking MYO cigarettes is not a safe alternative to FM cigarettes. Like FM, MYO cigarettes expose their users to harmful constituents of tobacco smoke. Despite differences in size and design their puffing profiles are remarkably similar.

IMPACT

These data are relevant to health and regulatory considerations on the MYO cigarettes.

Escalating doses of transdermal nicotine in heavy smokers: effects on smoking behavior and craving

Fixed-dose nicotine replacement therapy (NRT) is efficacious for smoking cessation in the general population of smokers. However, it is less effective in populations with psychiatric comorbidities and/or severe tobacco dependence where the percent nicotine replacement is suboptimal. The objective of this pilot study was to determine the effectiveness of nicotine patch dose titration in response to continued smoking in heavily dependent smokers with psychiatric comorbidity. In a single-arm, open-label study adult smokers (mean cigarettes per day, 25.4 ± 13.4; range, 14-43; n = 12) willing to quit were treated with escalating doses of transdermal nicotine and brief counseling intervention if they continued to smoke over a 9-week treatment period. Plasma nicotine and cotinine, along with expired carbon monoxide levels, and the subjective effects of smoking, urge to smoke, demand elasticity, and mood symptoms were also assessed. The mean NRT dose was 32.7 (SD, 16.4) mg/d (range, 7-56 mg/d). Smokers reported significant reductions in both cigarettes per day (mean decrease, 18.4 ± 11.5) confirmed by expired carbon monoxide (mean decrease, 13.5 ± 13.0) with no significant changes in plasma nicotine concentrations during the course of NRT dose titration. There were significant effects on the subjective effects of smoking and measures of smoking behavior. Most commonly reported adverse events were respiratory infections, skin irritation at patch site, nausea, and sleep disturbances, which were generally mild and transient. Titrating doses of NRT to effect with brief intervention hold promise as an effective clinical strategy to assist heavily dependent psychiatrically ill smokers to change their smoking behavior.

The effect of menthol on cigarette smoking behaviors, biomarkers and subjective responses

BACKGROUND

As part of the Family Smoking Prevention and Tobacco Control Act, the U.S. Food and Drug Administration charged the Tobacco Products Scientific Advisory Committee with developing a report and recommendations about the effect of menthol in cigarettes on the public health. The purpose of this study was to examine smoking behaviors, biomarkers of exposure, and subjective responses when switching from a novel menthol cigarette to a non-menthol cigarette to isolate the effect of menthol and to approximate the effect a menthol ban might have on smokers.

METHODS

Thirty-two adult smokers completed this 35-day randomized, open-label, laboratory study. After a 5-day baseline period, participants were randomized to the experimental group (n = 22) where they would smoke menthol Camel crush for 15 days followed by 15 days of non-menthol Camel crush, or the control group (n = 10) where they smoked their own brand cigarette across all periods. Participants attended study visits every 5 days and completed measures of smoking rate, smoking topography, biomarkers of exposure, and subjective responses.

RESULTS

Although total puff volume tended to increase when the experimental group switched from menthol to non-menthol (P = 0.06), there were no corresponding increases in cigarette consumption or biomarkers of exposure (P > 0.1). Subjective ratings related to taste and smell decreased during the non-menthol period (P < 0.01), compared with the menthol.

CONCLUSIONS

Results suggest menthol has minimal impact on smoking behaviors, biomarkers of exposure, and subjective ratings.

IMPACT

When controlling for all other cigarette design features, menthol in cigarettes had minimal effect on outcome measures.

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.

Lack of effect of menthol level and type on smokers' estimated mouth level exposures to tar and nicotine and perceived sensory characteristics of cigarette smoke

Menthol can reduce sensory irritation and it has been hypothesised that this could result in smokers of mentholated cigarettes taking larger puffs and deeper post-puff inhalations thereby obtaining higher exposures to smoke constituents than smokers of non-mentholated cigarettes. The aim of our study was to use part-filter analysis methodology to assess the effects of cigarette menthol loading on regular and occasional smokers of mentholated cigarettes. We measured mouth level exposure to tar and nicotine and investigated the effects of mentholation on smokers' sensory perceptions such as cooling and irritation. Test cigarettes were produced containing no menthol and different loadings of synthetic and natural l-menthol at 1 and 4mg ISO tar yields. A target of 100 smokers of menthol cigarettes and 100 smokers who predominantly smoked non-menthol cigarettes from both 1 and 4mg ISO tar yield categories were recruited in Poland and Japan. Each subject was required to smoke the test cigarette types of their usual ISO tar yield. There were positive relationships between menthol loading and the perceived 'strength of menthol taste' and 'cooling' effect. However, we did not see marked menthol-induced reductions in perceived irritation or menthol-induced increases in mouth level exposure to tar and nicotine.

Decreasing Nicotine Content Reduces Subjective and Physiological Effects of Smoking

OBJECTIVE

Assessment of the subjective and physiological effects of smoking cigarettes with different machine-smoked nicotine yields.

METHODS

Eight volunteers rated the characteristics of cigarettes with varying levels of nicotine (Quest^®). At 30 minute intervals, participants smoked one of three different Quest^® brand cigarettes in a counterbalanced order (reported machine-smoked nicotine yield: 0.6 mg, 0.3 mg, or 0.05 mg). Smoking satisfaction and sensations were measured on a cigarette evaluation questionnaire. A mood questionnaire measured self-reported subjective changes in 'happy', 'stimulated', 'anxious', 'desire to smoke', and 'desire not to smoke'. Heart rate and skin temperature were recorded continuously.

RESULTS

As nicotine yield decreased, cigarettes produced smaller changes in subjective ratings on the evaluation questionnaire with the placebo nicotine cigarette always rated lower or less potent than the other two cigarettes evaluated. Heart rate was significantly increased by the reduced nicotine cigarettes, but was not affected by the nicotine-free cigarette.

CONCLUSION

These results indicate that machine-smoked yield is an important determinant of both the subjective and physiological effects of smoking. The use of reduced and nicotine free cigarettes in smoking cessation programs remains to be evaluated.

Effect of menthol on nicotine pharmacokinetics in rats after cigarette smoke inhalation

INTRODUCTION

The effect of menthol on nicotine disposition is important in understanding smoking behaviors among different racial groups. The present study was to evaluate whether menthol affects the pharmacokinetics of nicotine after cigarette smoke inhalation.

METHODS

Rats were exposed to mainstream smoke from either a nonmentholated or mentholated cigarette (1 puff/min for 10 min) using a smoke inhalation apparatus. For the multiple-cigarette smoke inhalation, rats received the smoke from either nonmentholated or mentholated cigarette (10 puffs) every 12 hr for a total of 17 cigarettes. Serial blood samples were collected during the 10-min inhalation phase for the single-cigarette smoke or the 17th cigarette inhalation and for 30 hr thereafter. Nicotine and its major metabolite cotinine were assayed by radioimmunoassay methods.

RESULTS

Following single-cigarette smoke inhalation, mentholated cigarettes significantly decreased the mean peak concentrations of nicotine in plasma (C(max)) from 27.1 to 9.61 ng/ml and the total area under the plasma concentration-time curves (AUC) from 977 to 391 ng min/ml as compared with those after nonmentholated cigarette smoke inhalation. C(max) and AUC values for cotinine were also significantly reduced by menthol. Similarly after multiple smoke inhalation, C(max), AUC, and the mean average steady-state plasma concentration of nicotine as well as cotinine were significantly lower in mentholated cigarette inhalation. Interestingly, there was a significant increase in the cotinine to nicotine AUC ratio from 13.8 for the nonmentholated to 21.1 for the mentholated cigarette.

CONCLUSIONS

These results suggest that menthol in mentholated cigarettes can substantially decrease the absorption and/or increase the clearance of nicotine.

A survey of mouth level exposure to cigarette smoke in the United States

Smoke yields determined by a machine-based smoking method cannot adequately predict exposures experienced by human smokers. In this work, a filter analysis technique which addresses this fundamental limitation was used to measure mouth level exposures (MLE) to tar and nicotine in 1330 smokers of 26 brand-styles of US cigarettes covering a wide range of machine-generated yields. Despite the high degree of variability observed among individual smokers, MLEs were significantly correlated with machine-derived tar and nicotine yields (r=0.423 for nicotine MLE/cigarette; r=0.493 for tar MLE/cigarette; p<0.001 for both). Mean tar and nicotine MLE was higher for males than for females. Mean MLE across races was generally similar. Menthol cigarettes tended toward lower MLE than non-menthol cigarettes and King-Size cigarettes (≈ 83 mm) tended toward lower MLE than 100's cigarettes (≈ 100 mm), though those trends were not statistically significant. There were good agreements between MLEs measured in a group of 159 subjects smoking their usual cigarette brand-style on two separate occasions and between two independent groups of subjects smoking the same brand-styles. The results indicated that the filter analysis method used had sufficient precision to show similarity among groups.

Sensory properties of menthol and smoking topography

Although there is a great deal known about menthol as a flavoring agent in foods and confections, less is known about the particular sensory properties of menthol cigarette smoke. Similarly, although smoking topography (the unique way an individual smokes a cigarette) has been well studied using non-menthol cigarettes, there is relatively less known about how menthol affects smoking behavior. The objective of this review is to assess the sensory properties of menthol tobacco smoke, and smoking topography associated with menthol cigarettes. The cooling, analgesic, taste, and respiratory effects of menthol are well established, and studies have indicated that menthol’s sensory attributes can have an influence on the positive, or rewarding, properties associated smoking, including ratings of satisfaction, taste, perceived smoothness, and perceived irritation. Despite these sensory properties, the data regarding menthol’s effect on smoking topography are inconsistent. Many of the topography studies have limitations due to various methodological issues.

Systematic review of the epidemiological evidence comparing lung cancer risk in smokers of mentholated and unmentholated cigarettes

BACKGROUND

US mentholated cigarette sales have increased considerably over 50 years. Preference for mentholated cigarettes is markedly higher in Black people. While menthol itself is not genotoxic or carcinogenic, its acute respiratory effects might affect inhalation of cigarette smoke. This possibility seems consistent with the higher lung cancer risk in Black men, despite Black people smoking less and starting smoking later than White people. Despite experimental data suggesting similar carcinogenicity of mentholated and non-mentholated cigarettes, the lack of convincing evidence that mentholation increases puffing, inhalation or smoke uptake, and the similarity of lung cancer rates in Black and White females, a review of cigarette mentholation and lung cancer is timely given current regulatory interest in the topic.

METHODS

Epidemiological studies comparing lung cancer risk in mentholated and non-mentholated cigarette smokers were identified from MedLine and other sources. Study details were extracted and strengths and weaknesses assessed. Relative risk estimates were extracted, or derived, for ever mentholated use and for long-term use, overall and by gender, race, and current/ever smoking, and meta-analyses conducted.

RESULTS

Eight generally good quality studies were identified, with valid cases and controls, and appropriate adjustment for age, gender, race and smoking. The studies afforded good power to detect possible effects. However, only one study presented results by histological type, none adjusted for occupation or diet, and some provided no results by length of mentholated cigarette use.The data do not suggest any effect of mentholation on lung cancer risk. Adjusted relative risk estimates for ever use vary from 0.81 to 1.12, giving a combined estimate of 0.93 (95% confidence interval 0.84-1.02, n = 8), with no increase in males (1.01, 0.84-1.22, n = 5), females (0.80, 0.67-0.95, n = 5), White people (0.87, 0.75-1.03, n = 4) or Black people (0.90, 0.73-1.10, n = 4). Estimates for current and ever smokers are similar. The combined estimate for long-term use (0.95, 0.80-1.13, n = 4) again suggests no effect of mentholation.

CONCLUSION

Higher lung cancer rates in Black males cannot be due to their greater preference for mentholated cigarettes. While some study weaknesses exist, the epidemiological evidence is consistent with mentholation having no effect on the lung carcinogenicity of cigarettes.

The role of menthol in cigarettes as a reinforcer of smoking behavior

INTRODUCTION

The World Health Organization has identified several additives such as menthol in the manufacturing of cigarettes to specifically reduce smoke harshness. These additives may have important implications for reinforcing smoking behavior and motivation to quit smoking. The purpose of this paper is to synthesize research related to the role of menthol's sensory characteristics in strengthening the reinforcing effects of nicotine in cigarettes and the impact on nicotine addiction and smoking behavior.

METHODS

Research reports from 2002 to 2010 on the addictive potential of menthol cigarettes were reviewed that included qualitative focus groups, self-reports and biomarkers of nicotine dependence, human laboratory, and epidemiological studies.

RESULTS

Positive sensory effects of menthol cigarette use were identified via reports of early smoking experiences and as a potential starter product for smoking uptake in youth. Menthol cigarettes may serve as a conditioned stimulus that reinforces the rewarding effects of smoking. Nicotine dependence measured by shorter time-to-first cigarette upon waking was increased with menthol cigarette use in most of the studies reviewed. Smoking quit rates provide additional indicators of nicotine dependence, and the majority of the studies reviewed provided evidence of lower quit rates or higher relapse rates among menthol cigarette smokers.

CONCLUSIONS

The effects of menthol cigarette use in increasing the reinforcing effects of nicotine on smoking behavior were evidenced in both qualitative and quantitative empirical studies. These findings have implications for enhanced prevention and cessation efforts in menthol smokers.

A review and assessment of menthol employed as a cigarette flavoring ingredient

Cigarette smoking is established as a substantial contributor to risks for cancer, cardiovascular and respiratory diseases. Less is known about the potential of cigarette composition to affect smoking risks. The use of cigarette flavoring ingredients such as menthol is currently of worldwide public health and regulatory interest. The unique conditions of menthol inhalation exposure that occur coincident with that of the complex cigarette smoke aerosol require specialized studies to support an assessment of its safety in cigarette flavoring applications. The present state of knowledge is sufficient to support an assessment of the safety of the use of menthol in cigarettes. Scientific, smoking behavioral and epidemiological data available through mid-2009 is critically reviewed and a broad convergence of findings supports a judgment that menthol employed as a cigarette tobacco flavoring ingredient does not meaningfully affect the inherent toxicity of cigarette smoke or the human risks that attend smoking. There remains a need for well-designed studies of the potential of menthol to affect smoking initiation, cessation and addiction in order to differentiate any independent effects of menthol in cigarettes from those imposed by socioeconomic, environmental and peer influences on these complex human behaviors.

Smokers of menthol and nonmenthol cigarettes exhibit similar levels of biomarkers of smoke exposure

There has been speculation that the addition of menthol to cigarettes may affect the manner in which cigarettes are smoked, potentially influencing smokers' exposures to smoke constituents that have been associated with smoking-related diseases. One hundred twelve male and female smokers participated in a parallel-arm study to determine whether the ad libitum smoking of menthol cigarettes results in differences in smoke constituent exposure biomarkers in blood and urine relative to those smoking nonmenthol cigarettes having similar machine-measured (Federal Trade Commission) yields of approximately 9 to 10 mg "tar." The study subjects were provided cigarettes of their preferred menthol or nonmenthol types prior to two 24-hour study intervals spaced one week apart. Carboxyhemoglobin levels were measured in blood samples drawn at midafternoon following the two 24-hour urine collection periods. Six urinary nicotine metabolites (nicotine, cotinine, trans-3'-hydroxycotinine and respective glucuronides) were determined as measures of nicotine intake, and urinary 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronide were determined to assess exposure to the tobacco-specific nitrosamine 4-(N-nitrosomethylamino)-1-(3-pyridinyl)-1-butanone. Subjects' median blood carboxyhemoglobin values did not differ significantly between the cigarette types. Neither total urinary NNAL nor urinary nicotine equivalents exhibited statistically significant differences between the menthol and nonmenthol cigarette smokers. The present findings indicate that moderately heavy smokers of menthol and nonmenthol cigarettes of similar machine-generated smoke yield exhibit essentially identical levels of biomarkers of smoke constituent exposure. These results are consistent with the substantial majority of epidemiology studies to date that suggest the risks attending the smoking of menthol and nonmenthol cigarettes are similar.

Are menthol cigarettes a starter product for youth?

This study assessed the relationship between menthol use and nicotine dependence. Data from the National Youth Tobacco Survey indicated that menthol cigarette use was significantly more common among newer, younger smokers. Additionally, youth who smoked menthol cigarettes had significantly higher scores on a scale of nicotine dependence compared with nonmenthol smokers, controlling for demographic background and the length, frequency, and level of smoking. The study suggests that menthol cigarettes are a starter product that may be associated with smoking uptake by youth.

Possible effects on smokers of cigarette mentholation: a review of the evidence relating to key research questions

Menthol (2-isopropyl-5-methyl-cyclohexan-1-ol) is used in food, pharmaceutical, and tobacco products. Despite its long usage history and GRAS status, scientific literature on effects of cigarette mentholation is limited. Because African-American men have high lung cancer rates and predominantly smoke mentholated cigarettes, and because menthol's cooling effect might affect puffing and smoke inhalation, possible adverse effects of cigarette mentholation have been suggested. We review the evidence on the effects of mentholation on smokers, and we also identify areas for further study. Five large epidemiological studies provide no evidence that cigarette mentholation increases lung cancer risk. Mentholation cannot explain the higher risk for lung cancer in African-American male smokers, who also predominantly smoke mentholated cigarettes. Limited data on other cancers also suggest no risk from mentholation. The scientific literature suggests that cigarette mentholation does not increase puff number or puff volume of smoked cigarettes, and has little or no effect on heart rate, blood pressure, uptake of carbon monoxide, tar intake or retention, or blood cotinine concentration. Mentholation has little effect on other smoke constituents, and no apparent effect on nicotine absorption, airway patency and smoking initiation, dependency or cessation. Any toxicological effects of cigarette mentholation on adult smokers are probably quite limited.

Individual self-administration of nicotine by rats

Self-administration (SA) of nicotine (N) was studied in 20 male and 19 female N:NIH rats using the two-bottle method. The experimental protocol consisted of seven consecutive periods each lasting 6 days: Period (P)1, choice of water (W) and 0.003% N; P2, choice of W and 0.006% N; P3, choice of W and 0.012% N; P4, W only; P5, choice of W and 0.006% N; P6, 0.006% N only; and P7, choice of W and 0.006% N. Group means showed that males and female rats consumed similar amounts of N during Ps 1-3. After an N-free period (P4), a small decline was observed in the subsequent voluntary intake of N (P5). Forced N (P6) exposure did not affect a subsequent N intake (P7) in males but increased it slightly in females. A survey of individual animals, however, showed that the voluntary N consumption varied greatly among animals, but was quite consistent for a particular rat. Values ranged from 0.43 to 7.59 for males and from 0.35 to 4.69 mg/kg/day for females for Ps 1-3. The N-free (P4) and the forced-N (P6) periods each affected a subsequent voluntary N intake (P5, P7) of the rats very differently, but again consistently, in that some rats decreased, some increased and some did not change their N choice. The results indicate that group means can be misleading in their conclusions and strongly support the assumption that the response of an individual animal to N, and not N per se, is the determining force of its SA.

Clove cigarette smoking: biochemical, physiological, and subjective effects

Alternative tobacco products such as clove (kreteks) and bidi cigarettes have become increasingly popular among US smokers. The nicotine content of a popular clove cigarette (Djarum Special) filler averaged 7.4 mg; conventional cigarettes contained 13.0 mg. However, smoke yields from standardized machine-smoking analysis indicated it delivered more nicotine, carbon monoxide (CO), and tar than conventional cigarettes. In a clinical study, nicotine delivery, physiologic, and subjective effects of the clove cigarette were compared to their own brand of cigarette in 10 adult smokers (7 males). Average time to smoke the clove cigarette (549 s) and number of puffs (15.1) were significantly greater than own brand (314 s and 9.4 puffs). Increases in venous plasma nicotine and exhaled CO after smoking the clove cigarette (17.4 ng/ml; 6 ppm) were similar to those after own brand (17.6 ng/ml; 4.5 ppm). Maximal changes in heart rate (HR), systolic, and diastolic blood pressures (BP) did not differ significantly between the clove and own brand of cigarette. Compared to their own brand of cigarette, the clove cigarette was rated as better tasting and being distinctly different. Our findings indicate that clove cigarettes deliver significant quantities of nicotine, CO, and presumably other toxic components of tobacco smoke. Taste satisfaction, aromatic odor, and novelty may contribute to their appeal to young smokers.

Mentholated cigarettes and smoking habits in whites and blacks

OBJECTIVE

To determine if cigarette mentholation is associated with the frequency of smoking and with quitting, and whether mentholation explains racial differences in these two smoking behaviours.

DESIGN

Cross sectional analysis of case-control data on smoking and lung cancer.

SUBJECTS

Limited to 19 545 current and former cigarette smokers.

MAIN OUTCOME MEASURES

Smoking > 20 cigarettes per day (cpd) versus < or = 20 cpd, and continued smoking versus quit smoking.

RESULTS

Among blacks, the prevalence odds ratio (POR) of heavy smoking (> or = 21 cpd) associated with mentholated cigarettes versus non-mentholated cigarettes was 0.7 (95% confidence interval (CI) 0.5 to 0.9) in current smokers and 0.6 (95% CI 0.4 to 0.9) in former smokers. Among whites, the corresponding POR were 0.9 (95% CI 0.8 to 1.0) and 0.9 (95% CI 0.8 to 1.0). Blacks were less likely to have been heavy smokers than whites, but the difference was unrelated to cigarette mentholation. The POR of continued smoking versus quitting, associated with mentholated cigarettes was 1.1 (95% CI 1.0 to 1.2) for both blacks and whites.

CONCLUSION

Smoking > 20 cpd was independently associated with white race. Among blacks, smoking < or = 20 cpd was independently associated with mentholated cigarettes. The risk of quitting was not associated with cigarette menthol flavour.