Genetic Vulnerability to Menthol Cigarette Preference in Women

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Electronic Cigarette Use during Pregnancy: Is It Harmful?

Although combustible cigarette smoking rates have declined in recent years, alternative tobacco product use, particularly electronic cigarette use ("vaping"), has increased among young adults. Recent studies indicate that vaping during pregnancy is on the rise, possibly due to the perception that it is a safer alternative to combustible cigarette smoking. However, e-cigarette aerosols may contain several newer, potentially toxic compounds, including some known developmental toxicants that may adversely impact both the mother and the fetus. However, there is paucity of studies that have examined the effects of vaping during pregnancy. While the adverse perinatal outcomes of cigarette smoking during pregnancy are well established, the specific risks associated with inhaling vaping aerosols during pregnancy requires more research. In this article, we discuss the existing evidence and knowledge gaps on the risks of vaping during pregnancy. Studies that investigate vaping-associated systemic exposure and its effects (i.e., biomarker analyses) and maternal and neonatal clinical health outcomes are needed to reach more robust conclusions. We particularly emphasize the need to go beyond comparative studies with cigarettes, and advocate for research that objectively evaluates the safety of e-cigarettes and other alternative tobacco products.

Clinical Associations of Bitter Taste Perception and Bitter Taste Receptor Variants and the Potential for Personalized Healthcare

Bitter taste receptors (T2Rs) consist of 25 functional receptors that can be found in various types of cells throughout the human body with responses ranging from detecting bitter taste to suppressing pathogen-induced inflammation upon activation. Numerous studies have observed clinical associations with genetic or phenotypic variants in bitter taste receptors, most notably that of the receptor isoform T2R38. With genetic variants playing a role in the response of the body to bacterial quorum-sensing molecules, bacterial metabolites, medicinal agonists and nutrients, we examine how T2R polymorphisms, expression levels and bitter taste perception can lead to varying clinical associations. From these genetic and phenotypic differences, healthcare management can potentially be individualized through appropriately administering drugs with bitter masking to increase compliance; optimizing nutritional strategies and diets; avoiding the use of T2R agonists if this pathway is already activated from bacterial infections; adjusting drug regimens based on differing prognoses; or adjusting drug regimens based on T2R expression levels in the target cell type and bodily region.

Genetic variations in the bitter taste receptor gene TAS2R38 are related to cigarette smoking behavior in Han Chinese smokers

BACKGROUND

Smoking behavior is influenced by multiple genes, including the bitter taste gene TAS2R38. It has been reported that the correlation between TAS2R38 and smoking behavior has ethnicity-based differences. However, the TAS2R38 status in Chinese smokers is still unclear.

OBJECTIVE

This study aims to investigate the possible relationship between genetic variations in TAS2R38 (A49P, V262A and I296V) and smoking behaviors in the Han Chinese population.

METHODS

The haplotype analyses were performed and smoking behavior questionnaire was completed by 1271 individuals. Genetic association analyses for smoking behavior were analyzed using chi-square test. Further, for investigating the molecular mechanism of TAS2R38 variants effect on smoking behavior, we conducted TAS2R38-PAV and TAS2R38-AVI expression plasmids and tested the cellular calcium assay by cigarette smoke compounds stimulus in HEK293.

RESULTS

Significant associations of genetic variants within TAS2R38 were identified with smoking behavior. We found a higher PAV/PAV frequency than AVI/AVI in moderate and high nicotine dependence (FTND ≥ 4; X² = 4.611, 1 df, p = 0.032) and strong cigarette smoke flavor intensity preference (X² = 4.5383, 1 df, p = 0.033) in participants. Furthermore, in the in vitro cellular calcium assay, total particle matter (TPM), N-formylnornicotine and cotinine, existing in cigarette smoke, activated TAS2R38-PAV but not TAS2R38-AVI-transfected cells.

CONCLUSION

Our data highlights that genetic variations in TAS2R38 are related to smoking behavior, especially nicotine dependence and cigarette smoke flavor intensity preference. Our findings may encourage further consideration of the taste process to identify individuals susceptible to nicotine dependence, particularly Han Chinese smokers.

Flavor science in the context of research on electronic cigarettes

Thousands start smoking or vaping daily, despite long-standing efforts by public health authorities to curb initiation and use of nicotine containing products. Over the last 15 years, use of electronic nicotine delivery systems has increased dramatically, with a diverse range of products on the market, including pod-based, disposable, and refillable electronic cigarettes (eCigs). Originally intended for harm reduction and smoking cessation, eCigs may encourage nicotine use among never smokers, given the vast range of appealing flavors that are available. To better understand abuse liability and to facilitate appropriate regulations, it is crucial to understand the science of flavor, and flavor perception within the context of eCig use. Here, we (a) provide a brief primer on chemosensory perception and flavor science for addiction and nicotine researchers, and (b) highlight existing some literature regarding flavor and nicotine use, with specific attention given to individual differences in perception, and interaction between different sensory modalities that contribute to flavor. Dramatic increases in use of eCigs highlights the importance of flavor science in contemporary addiction research, both with regards to public health and regulatory efforts. Other recent work summarizes findings on flavored e-liquids and eCig use, but none have focused explicitly on chemosensory processes or flavor perception as they relate to appeal and use of such products. We argue flavor science needs to be considered as perceptual and behavioral phenomena, and not merely from analytical, toxicological and pharmacological perspectives; we help address this gap here.

Chemosensory Contributions of E-Cigarette Additives on Nicotine Use

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

Does genetic variation in a bitter taste receptor gene alter early smoking behaviours in adolescents and young adults?

BACKGROUND AND AIMS

Variation in the TAS2R38 taste receptor gene alters the ability to taste bitter compounds. We tested whether TAS2R38 variation influences early smoking behaviours in adolescence, a critical period of acquisition when taste may influence the natural course of tobacco use.

DESIGN AND PARTICIPANTS

Observational study (Nicotine Dependence in Teens [NDIT]). Cox proportional hazards models were conducted using data from European ancestry adolescent participants who initiated smoking during follow-up (n = 219, i.e. incident smokers). In young adulthood, cross-sectional analyses were restricted to European ancestry self-reported current smokers at age 24 (n = 148).

SETTING

Montréal, Canada.

MEASUREMENTS

In adolescents, the rates of attaining early smoking milestones were estimated for tasters {PAV diplotypes (i.e. PAV/PAV or PAV/AVI)} versus non-tasters {AVI diplotype (i.e. AVI/AVI)}. In young adults, associations between tasting status and a nicotine intake biomarker (cotinine + 3'hydroxycotinine) and past-week cigarette consumption were assessed.

FINDINGS

Among incident smokers, similar rates to first whole cigarette were found between the diplotype groups (hazard ratio [HR], 1.05; 95% confidence interval (CI), 0.75-1.48; P = 0.765). However, smokers with the PAV (vs AVI) diplotypes attained monthly smoking more rapidly (HR, 1.55; 95% CI, 1.04-2.32; P = 0.033) and had faster conversion to three different measures of tobacco dependence (International Classification of Diseases: HR, 2.29; 95% CI, 0.99-5.28; P = 0.052; modified Fagerström Tolerance Questionnaire: HR, 3.02, 95% CI, 1.04-8.79; P = 0.043; Hooked on Nicotine Checklist: HR, 1.87; 95% CI, 0.98-3.60; P = 0.059). At age 24, those with PAV (vs AVI) diplotypes had higher mean cotinine + 3'hydroxycotinine (197 vs 143 ng/mL; P = 0.053).

CONCLUSIONS

Adolescents with a genetic variation increasing their ability to taste bitter compounds appear to escalate more quickly to monthly smoking and tobacco dependence during adolescence and have higher nicotine intake in young adulthood versus those without that genetic variation.

Use and perceptions of menthol versus non-menthol cigarettes among pregnant women

BACKGROUND

Menthol cigarette use among women who smoke cigarettes during pregnancy is high, but little is known about the factors that contribute to preference for menthol cigarette use during pregnancy.

OBJECTIVE

This study investigated preferences, perceptions, and intentions to use menthol vs. non-menthol cigarettes in a sample of pregnant women.

METHODS

Pregnant women (N = 124, Mage = 26.2 years, 50% minorities) completed a study investigating the impact of maternal smoking on biobehavioral markers of fetal risk. During the third trimester, participants self-reported preferences (liking, attractiveness, smoothness, interest), perceptions of harm (general, pregnancy-specific), and intentions to use menthol and non-menthol cigarettes. We examined differences in responses based on whether participants endorsed (1) cigarette use during pregnancy (yes/no) and (2) lifetime cigarette use (yes/no).

RESULTS

Sixty-two participants endorsed cigarette smoking during pregnancy (85.5% smoked menthol cigarettes), and 94 participants reported lifetime use. Overall, menthol cigarettes were perceived as more likeable and smoother vs. non-menthol (ps < .001) - even among participants who never smoked cigarettes (ps < .05). All participants rated both menthol and non-menthol cigarette use as harmful. Compared to participants who did not smoke during pregnancy, participants who smoked during pregnancy rated menthol cigarettes as less harmful for pregnant women (p = .001), while there were no differences between groups in harm perceptions toward non-menthol cigarettes.

CONCLUSIONS

Menthol may increase cigarettes appeal for pregnant women. Implications for regulation of menthol cigarettes are discussed. Future studies may investigate the role of sensory perception, marketing, and health education in influencing these factors.

Automated Solid Phase Extraction and Polarity-Switching Tandem Mass Spectrometry Technique for High Throughput Analysis of Urine Biomarkers for 14 Tobacco-related Compounds

Tobacco use is the leading preventable cause of premature disease and death in the United States. Approximately, 34 million U.S. adults currently smoke cigarettes. We developed a method for automated sample preparation and liquid chromatography-tandem mass spectrometry quantitation of 14 tobacco-related analytes: nicotine (NICF), cotinine (COTF), trans-3'-hydroxycotinine (HCTF), menthol glucuronide (MEG), anabasine (ANBF), anatabine (ANTF), isonicoteine (ISNT), myosmine (MYOS), beta-nicotyrine (BNTR), bupropion (BUPR), cytisine (CYTI), varenicline (VARE), arecaidine (ARD), and arecoline (ARL). The method includes automated solid-phase extraction using customized positive-pressure functions. The preparation scheme has the capacity to process a batch of 96 samples within 4 h with greater than 88% recovery for all analytes. The 14 analytes, separated within 4.15 min using reversed-phase liquid chromatography, were determined using a triple-quadrupole mass spectrometer with atmospheric-pressure chemical ionization and multiple reaction monitoring in negative and positive ionization modes. Wide quantitation ranges, within 1.2-72,000 ng/mL, were established especially for COTF, HCTF, MEG, and NICF to quantify the broad range of biomarker concentrations found in the U.S. population. The method accuracy is above 90% while the overall imprecision is below 7%. Finally, we tested urine samples from 90 smokers and observed detection rates of over 98% for six analytes with urinary HCTF and MEG concentrations ranging from 200-14,100 and 60-57,100 ng/mL, respectively. This high throughput analytical process can prepare and analyze a sample in 9 min and along with the 14-compound analyte panel can be useful for tobacco-exposure studies, in smoking-cessation programs, and for detecting changes in exposure related to tobacco products and their use.

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

INTRODUCTION

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

AIMS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPLICATIONS

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

Associations between chronic cigarette smoking and taste function: Results from the 2013-2014 national health and nutrition examination survey

We identified associations between cigarette-smoking and taste function in the U.S. NHANES 2013-2014. Adults ≥ 40 years (n = 2849, nearly half former or current smokers) rated whole-mouth and tongue-tip bitter (1 mM quinine) and salt (1 M NaCl, 0.32 M NaCl) intensities and reported smoking history (pack years, PY), dependence (time to first cigarette, TTFC) and menthol/non-menthol use. Perceived intensity on the tongue-tip averaged just below moderate for quinine and moderate to strong for 1 M NaCl. Current chronic smokers (≥ 20 PY) reported lower bitter and salty intensities on the tongue-tip (β: -2.0, 95% CI: -3.7 to -0.4 and β: -3.6, 95% CI: -6.9 to -0.3, respectively) than never smokers. Similarly, compared to never smokers, dependent current smokers (TTFC ≤ 30 min) and dependent chronic smokers (≥ 20 PY, TTFC ≤ 30 min) rated less bitter (β: -2.0, 95% CI: -4.0 to 0.1 and β: -2.9, 95% CI: -4.5 to -1.3, respectively) and salty (β: -5.3, 95% CI: -9.3 to -1.4 and β: -4.7, 95% CI: -8.6 to -0.7, respectively) intensities on the tongue-tip. Depressed tongue-tip intensity in dependent smokers (with/without chronicity) versus never smokers was significant in younger (40-65 years), but not older (> 65 years) adults. Former smokers, non-chronic/less dependent smokers, and menthol smokers were more likely to report elevated whole-mouth quinine and 1 M NaCl intensities. Tongue-tip and whole-mouth taste intensity concordance varied between smokers and never smokers-current dependent smokers were more likely to rate tongue-tip quinine and NaCl lower than their respective whole-mouth tastants (OR: 1.8, 95% CI: 1.0 to 3.1 and OR: 1.8, 95% CI: 1.1 to 2.8, respectively). In summary, these U.S. nationally-representative data show that current smoking with chronicity and/or dependence associates with lower tongue-tip intensity for bitter and salty stimuli. Smokers with greater exposure to nicotine and/or dependence showed greater risk of taste alterations, with implications for diet- and smoking-related health outcomes.

COVID-19 as a worldwide selective event and bitter taste receptor polymorphisms: An ecological correlational study

Background

Given the observed olfactory and gustatory dysfunctions in patients with COVID-19 and recent findings on taste receptors possible important activities in the immune system, we elected to estimate the correlation between COVID-19 mortality and polymorphism of a particular type of bitter taste receptor gene called TAS2R38, in a worldwide epidemiological point of view.

Methods

Pooled rate of each of the rs713598, rs1726866, rs10246939, and PAV/AVI polymorphisms of the TAS2R38 gene was obtained in different countries using a systematic review methodology and its relationship with the mortality of COVID-19. Data were analyzed by the comprehensive meta-analysis software and SPSS.

Results

There was only a significant reverse Pearson correlation in death counts and PAV/AVI ratio, p = 0.047, r = −0.503. Also, a significant reverse correlation of PAV/AVI ratio and death rate was seen, r = −0.572 p = 0.021. rs10246939 ratio had a significant positive correlation with death rate, r = 0.851 p = 0.031. Further analysis was not significant. Our results showed that the higher presence of PAV allele than AVI, and a higher rate of G allele than A in rs10246939 polymorphism in a country, could be associated with lower COVID-19 mortality. While assessing all three polymorphisms showed a huge diversity worldwide.

Conclusion

Due to extraoral activities of bitter taste receptor genes, especially in mucosal immunity, this gene seems to be a good candidate for future studies on COVID-19 pathophysiology. Also, the high worldwide diversity of TAS2R38 genes polymorphism and its possible assassination with mortality raises concerns about the efficiency of vaccine projects in different ethnicities.

High Rates of Menthol Cigarette Use Among Pregnant Smokers: Preliminary Findings and Call for Future Research

INTRODUCTION

Smoking during pregnancy remains widespread and is causally associated with infant morbidity and mortality. Despite links between menthol cigarette use and decreased smoking cessation, little is known regarding rates or characteristics of pregnant menthol cigarette smokers.

METHODS

Participants were drawn from two low-income, racially/ethnically diverse cohorts of pregnant smokers recruited from 2006 to 2015 (N = 166, Mage = 25 ± 5). Demographics, menthol cigarette use, daily cigarette use, quit status, and consecutive weeks quit were assessed by prospective interviews. Nicotine dependence was assessed using the Fagerström Test of Nicotine Dependence. Nicotine levels were assessed via saliva cotinine.

RESULTS

High rates of menthol use were found in both cohorts (85% and 87%). Across both cohorts, menthol smokers were more likely to identify as racial/ethnic minorities, were less educated, and reported lower income than non-menthol smokers (ps < .03). Menthol smokers also reported fewer continuous weeks quit (8.4 vs. 14.5 weeks quit; p < .03) and a tendency toward decreased likelihood of quitting smoking over pregnancy (29% vs. 48%; p < .08) in unadjusted but not in covariate-adjusted analyses. No differences emerged in cigarettes per day, nicotine dependence or nicotine exposure.

CONCLUSIONS

We found very high rates of menthol cigarette use in pregnant smokers-particularly among racial/ethnic minority and low socioeconomic status smokers-and some evidence for associations with reduced smoking cessation in pregnancy. Consideration of pregnant smokers as a uniquely vulnerable population is warranted in evaluating regulation of menthol in cigarettes. Further research is needed regarding the impact of menthol on smoking persistence in pregnancy and on maternal and infant health outcomes.

IMPLICATIONS

This study highlights high rates of menthol cigarette use in pregnant women in the Northeast, United States, with evidence for higher rates of menthol use among racial/ethnic minority, less educated and low-income pregnant smokers, and preliminary evidence for associations between menthol cigarette use and reduced smoking cessation. Consideration of the effects of menthol on smoking persistence in pregnant women and on the health of their offspring is warranted in the development of regulations regarding menthol in cigarettes.

Measures of dependence in menthol and nonmenthol smokers - A comprehensive narrative review

Introduction. More than a decade ago, concerns were raised that menthol in cigarettes might enhance addiction to smoking. This article provides a comprehensive review of published studies examining cigarette dependence among menthol and nonmenthol smokers. The purpose of the review is to evaluate the scientific evidence to determine if menthol increases cigarette dependence. Materials and Methods. The published literature was searched in 2019 for studies that provide evidence on cigarette dependence among menthol compared to nonmenthol smokers. Included in this review are published studies that compare menthol and nonmenthol smokers based on widely accepted and validated measures of dependence, or other established predictors of dependence (age of smoking initiation [first cigarette]/age of progression [regular/daily smoking]) and indicators of dependence (smoking frequency, cigarettes smoked per day, time to first cigarette after waking, night waking to smoke, smoking duration). Results and Conclusion. Based on a review of the available studies, including those with adjusted results and large representative samples, reliable and consistent empirical evidence supports a conclusion that menthol smokers are not more dependent than nonmenthol smokers and thus menthol in cigarettes does not increase dependence.

Sex differences in the appeal of flavored e-cigarettes among young adult e-cigarette users

Experimental evidence suggests that females (vs. males) may be more sensitive to and derive greater reinforcement from the sensory aspects of combustible cigarette smoking (e.g., flavor, taste). However, it is unknown if there are similar sex differences in the appeal of flavored e-cigarettes. Young adult male (N = 65) and female (N = 35) e-cigarette users (mean age = 25.4; 53% current smokers) attended 1 laboratory session in which they self-administered standardized e-cigarette doses according to a Flavor (fruit vs. tobacco vs. menthol) × Nicotine (6 mg/mL vs. 0 mg/mL) × Voltage (3.3 V vs. 4.3 V) within-participant fully crossed factorial design. Following each trial, participants completed ratings of appeal (mean of liking, disliking [reverse scored], and willingness-to-use-again ratings). Sex was tested as a between-subjects moderator of the effects of flavor on appeal. There was a significant interaction between sex and flavor for e-cigarette appeal (p < .001). In males, fruit-flavored e-cigarettes generated greater appeal than menthol and tobacco (ps < .001). In females, both fruit- and menthol-flavored e-cigarettes generated greater appeal than tobacco (ps < .001), but there was no significant difference between fruit- and menthol-flavored e-cigarettes (p = .40). The findings of this study suggest that males prefer fruit-flavored e-cigarettes, and females prefer both menthol- and fruit-flavored e-cigarettes. The impact of regulatory policies targeting e-cigarette flavors in the population may vary by sex. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The Prevalence of Tobacco and E-Cigarette Use in Poland: A 2019 Nationwide Cross-Sectional Survey

Monitoring of tobacco use is one of the key tobacco control activities. This study aimed to assess the current prevalence and patterns of tobacco and e-cigarette in Poland as well as to investigate socioeconomic factors associated with cigarette smoking and e-cigarette use. This cross-sectional study was carried out in 2019, on a representative nationwide sample of 1011 individuals aged 15+ in Poland. Daily tobacco smoking was declared by 21.0% of participants; 1.3% of participants were occasional tobacco smokers, and 10.7% were former tobacco smokers. Heated tobacco was used by 0.4% of participants. Ever e-cigarette use was declared by 4.0% of participants and 1.4% were current e-cigarette users. A higher proportion of daily smokers was observed among men than women (24.4% vs. 18.0%; p < 0.0001). The age group 30 to 49 years, of a lower educational level and living in a medium-sized city (between 20,000 and 500,000 residents), was significantly associated with current daily smoking. This is the most up-to-date study on the prevalence of smoking in Poland. Further tobacco control activities are needed to reduce tobacco use in Poland.

[Vulnerability of women to tobacco: The broncho-pulmonary consequences (asthma, COPD)]

Smoking remains common, with an exposure that begins early during pregnancy. It induces epigenetic changes, with a trans-generational transmission. Smoking increases the risk of uncontrolled asthma during childhood and adult life. Asthma is also associated with increased risk of a decline of lung function and chronic obstructive pulmonary disease (COPD). Women are more at risk of developing early and severe COPD. The mechanisms are currently poorly known.

Flavored electronic cigarette use, preferences, and perceptions in pregnant mothers: A correspondence analysis approach

Use, preferences, and perceptions of flavored electronic cigarettes (e-cigarettes) were investigated in an ethnically diverse sample of pregnant mothers (N = 100; 50% smokers, M_age = 26; 66% low income; 65% minorities) via detailed interviews. Fruit and mint were the most commonly used flavors. Pregnant women endorsed increased use of fruit flavored e-cigarettes in preconception and pregnancy, greater preferences and intentions to use sweet flavors (fruit and candy), and lowest preferences for tobacco flavors. No differences in perceptions of general, pregnancy, or fetal-related health risks emerged across flavors. Latent factor mapping (biplots) based on correspondence analyses of contingency tables revealed clustering of more-preferred fruit and candy flavors versus least-preferred tobacco flavored e-cigarettes, with other sweet flavors-mint and alcohol-clustering more closely with fruit and candy flavors, and more pungent flavors-spice, coffee, chocolate-clustering near tobacco. Correspondence analysis also revealed uncorrelated clustering of preferences and harm perceptions, with intentions showing associations with both preferences and harm perceptions. Preference for fruit and mint flavored e-cigarettes and decreased harm perceptions significantly differentiated lifetime e-cigarette users from non-users. Results highlight preferences for fruit and mint flavored e-cigarettes during preconception and pregnancy, and links between preferences for fruit and mint flavors and lifetime use of e-cigarettes. These findings also highlight the utility of correspondence analysis for elucidating clustering of flavor perceptions and preferences for novel tobacco products.

E-cigarette palatability in smokers as a function of flavorings, nicotine content and propylthiouracil (PROP) taster phenotype

BACKGROUND

The popularity of E-cigarettes is due in part to their flavorings. The purpose of this study was to determine the effect on smokers' sensory perceptions and liking of various e-cigarette flavorings, and the degree to which those perceptions are influenced by nicotine level, sex, and PROP bitter taster phenotype.

METHODS

We recruited 132 non-treatment-seeking, daily cigarette smokers. In repeated trials in one laboratory session participants vaped the Joyetech eGo-C e-cigarette with each of the following flavorings (in random order): unflavored, tobacco, cherry, chocolate, and menthol. Participants vaped the e-juice first without nicotine and then with high nicotine (18 mg/ml), and provided sensory (bitterness/sourness, irritation, sweetness) and liking ratings. Perceived intensity of 6-n-propylthiouracil (PROP) was used to classify the participants as non-tasters (n = 28), medium-tasters (n = 74), or supertasters (n = 28). Mixed-effects linear models and generalized estimating equations were used to evaluate ratings as a function of flavor interacting with nicotine content, sex and taster phenotype, adjusting for age, race/ethnicity, menthol use, and nicotine dependence.

RESULTS

Regardless of nicotine level, cherry (β = 1.76, p < .001) and chocolate (β = 0.69, p < .001) were rated as sweeter, but were not better liked, than unflavored e-juice. Menthol elicited the highest liking rating, especially for women (β = 12.23, p < .05) and supertasters (β = 20.52, p < .05). Regardless of flavor, high nicotine was rated as more irritating (OR = 1.43, 95% CI = 1.02-2.01) than the no-nicotine e-juice. Irritation (β = -13.65, p < .001), bitterness/sourness (β = -11.38, p < .001), and sweetness (β = 4.79, p < .001) were associated with liking.

CONCLUSION

Menthol may enhance e-cigarette palatability for some smokers, which may increase e-cigarette utility in smoking cessation.

An African-specific haplotype in MRGPRX4 is associated with menthol cigarette smoking

In the U.S., more than 80% of African-American smokers use mentholated cigarettes, compared to less than 30% of Caucasian smokers. The reasons for these differences are not well understood. To determine if genetic variation contributes to mentholated cigarette smoking, we performed an exome-wide association analysis in a multiethnic population-based sample from Dallas, TX (N = 561). Findings were replicated in an independent cohort of African Americans from Washington, DC (N = 741). We identified a haplotype of MRGPRX4 (composed of rs7102322[G], encoding N245S, and rs61733596[G], T43T), that was associated with a 5-to-8 fold increase in the odds of menthol cigarette smoking. The variants are present solely in persons of African ancestry. Functional studies indicated that the variant G protein-coupled receptor encoded by MRGPRX4 displays reduced agonism in both arrestin-based and G protein-based assays, and alteration of agonism by menthol. These data indicate that genetic variation in MRGPRX4 contributes to inter-individual and inter-ethnic differences in the preference for mentholated cigarettes, and that the existence of genetic factors predisposing vulnerable populations to mentholated cigarette smoking can inform tobacco control and public health policies.

Heightened olfactory dysfunction and oral irritation among chronic smokers and heightened propylthiouracil (PROP) bitterness among menthol smokers

Chronic cigarette smoking may influence chemosensory function, which in turn, may affect cigarette usage. Because menthol in cigarettes can attenuate nicotine bitterness, choice of menthol/nonmenthol cigarettes may be influenced by ability to perceive bitterness. We examined chemosensory function of chronic smokers, hypothesizing they would show altered function in comparison to non-smokers and by menthol cigarette preference. In laboratory-based measures, chronic smokers (N = 135; 84 menthol smokers) self-reported their chemosensory function and participated in smell (identification task with perceived intensity) and taste (quinine and NaCl intensity on tongue-tip and whole mouth) testing. A taste genetics probe (propylthiouracil (PROP) bitterness) also was assessed. Self-reported and measured chemosensory function were compared with nationally-representative 2013-2014 National Health and Nutrition Examination Survey (NHANES) data generated with similar measures. The taste measures also were compared between smokers and age- and sex-matched non-smokers from a laboratory database. Frequencies of self-reported smell and taste alterations among smokers exceeded NHANES prevalence estimates for non-smokers. The rate of measured smell dysfunction also exceeded NHANES prevalence for hyposmia. Compared to non-smokers, smokers reported elevated tongue-tip and whole mouth intensities from 1 M NaCl, with no significant differences in whole mouth quinine or 0.32 M NaCl. Inconsistent with previous hypotheses, smokers were not more likely to report depressed PROP bitterness than non-smokers. However, as expected, menthol smokers reported greater PROP bitterness than non-menthol smokers. In conclusion, chemosensory alterations were more frequent among chronic smokers, including hyposmia and heightened intensity from NaCl at an oral-irritant concentration. PROP supertasters were most likely to prefer mentholated cigarettes.

Self-reported Smoking Status, TAS2R38 Variants, and Propylthiouracil Phenotype: An Exploratory Crowdsourced Cohort Study

TAS2R38 gene variants, which confer sensitivity to specific bitter tastants (e.g., 6-n-propylthiouracil), have been repeatedly associated with lower alcohol use via greater bitterness perception, but research exploring TAS2R38 variation in relation to smoking shows mixed results. In both, the working hypothesis is that 1 or more copies of the functional allele increases bitterness and may provide a barrier to early use. Such a barrier to initiation may, conceivably, manifest as differential rates of current use across diplotypes. Here, an age-diverse convenience sample (n = 886) of Denver Museum of Nature and Science guests was used to explore cross-sectional relationships between TAS2R38 diplotype, self-reported tobacco use (current, former, never smokers), and a rapid measure of 6-n-propylthiouracil phenotype (bitterness of filter paper discs). TAS2R38 diplotypes were determined by Sanger sequencing. After excluding rare diplotypes, data from 814 participants were analyzed. A mix of current (~10%), former (25%), and never smokers (65%) were included. As expected, there was a relationship between TAS2R38 diplotype and 6-n-propylthiouracil bitterness. However, contrary to our hypothesis, there was no evidence of a relationship between diplotype and smoker status among participants with common TAS2R38 diplotypes. Notably, we observed a relationship between of 6-n-propylthiouracil bitterness and smoking status, but the effect was opposite of what was expected: current smokers perceived higher (not lower) bitterness than never smokers. When all the various factors (diplotype, age, sex, and smoking status) were included in ANOVA, all remained predictive of 6-n-propylthiouracil bitterness. Reasons for greater phenotypic bitterness among current smokers are unknown and merit further study.

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

Purpose of review

To summarize current research on gender differences in mentholated cigarette use and related outcomes. Secondarily, to summarize literature on gender differences in mentholated cigarette use and related outcomes among Black smokers.

Recent findings

Women smokers are more likely to use menthol cigarettes than men. Other than prevalence, there is a paucity of research on gender differences in menthol related outcomes (e.g., cessation, disease). Among both women and men, menthol preference is stable during adolescence and young adulthood. A substantial portion of both women and men who smoke menthol report an expectation of quitting should menthol be banned. We did not identify any studies of gender differences in mentholated cigarette use among Black smokers.

Summary

Despite public health relevance, there is little current research on gender differences in mentholated cigarette use, other than studies of prevalence, and very little research on gender differences among Black smokers, including prevalence.

Menthol disrupts nicotine's psychostimulant properties in an age and sex-dependent manner in C57BL/6J mice

Menthol is a commonly used flavorant in tobacco and e-cigarettes, and could contribute to nicotine sensitivity. To understand how menthol could contribute to nicotine intake and addiction, it is important to determine whether specific mechanisms related to sex and age could underlie behavioral changes induced by menthol-laced nicotinic products. Using a validated paradigm of nicotine-dependent locomotor stimulation, adolescent and adult C57BL/6J mice of both sexes were exposed to nicotine, or nicotine laced with menthol, as their sole source of fluid, and psychostimulant effects were evaluated by recording home cage locomotor activity for ten days. Nicotine and cotinine blood levels were measured following exposure. Results show an interaction between treatment, age, and sex on liquid consumption, indicating that mice responded differently to menthol and nicotine based on their age and sex. Adult male mice greatly increased their nicotine intake when given menthol. In female mice of both age groups, menthol did not have this effect. Despite an increase in nicotine intake promoted by menthol, adult male mice showed a significant decrease in locomotion, suggesting that menthol blunted nicotine-induced psychostimulation. This behavioral response to menthol was not detected in adolescent mice of either sex. These data confirm that menthol is more than a flavorant, and can influence both nicotine intake and its psychostimulant effects. These results suggest that age- and sex-dependent mechanisms could underlie menthol's influence on nicotine intake and that studies including adolescent and adult menthol smokers of both sexes are warranted.

Genetic Variation in the TAS2R38 Bitter Taste Receptor and Smoking Behaviors

Common TAS2R38 taste receptor gene variants specify the ability to taste phenylthiocarbamide (PTC), 6-n-propylthiouracil (PROP) and structurally related compounds. Tobacco smoke contains a complex mixture of chemical substances of varying structure and functionality, some of which activate different taste receptors. Accordingly, it has been suggested that non-taster individuals may be more likely to smoke because of their inability to taste bitter compounds present in tobacco smoke, but results to date have been conflicting. We studied three cohorts: 237 European-Americans from the state of Georgia, 1,353 European-Americans and 2,363 African-Americans from the Dallas Heart Study (DHS), and 4,973 African-Americans from the Dallas Biobank. Tobacco use data was collected and TAS2R38 polymorphisms were genotyped for all participants, and PTC taste sensitivity was assessed in the Georgia population. In the Georgia group, PTC tasters were less common among those who smoke: 71.5% of smokers were PTC tasters while 82.5% of non-smokers were PTC tasters (P = 0.03). The frequency of the TAS2R38 PAV taster haplotype showed a trend toward being lower in smokers (38.4%) than in non-smokers (43.1%), although this was not statistically significant (P = 0.31). In the DHS European-Americans, the taster haplotype was less common in smokers (37.0% vs. 44.0% in non-smokers, P = 0.003), and conversely the frequency of the non-taster haplotype was more common in smokers (58.7% vs. 51.5% in non-smokers, P = 0.002). No difference in the frequency of these haplotypes was observed in African Americans in either the Dallas Heart Study or the Dallas Biobank. We conclude that TAS2R38 haplotypes are associated with smoking status in European-Americans but not in African-American populations. PTC taster status may play a role in protecting individuals from cigarette smoking in specific populations.

Effect of Menthol-preferring Status on Response to Intravenous Nicotine

OBJECTIVES

Menthol, a flavoring agent, is found in approximately 90% of cigarettes, but at much higher levels in menthol than non-menthol cigarettes. Menthol is reportedly included in cigarettes for its cooling and soothing effects, but also additional actions that affect smokers' receipt and processing of nicotine. In this study we investigated the response to short-term abstinence and acute nicotine delivery in menthol-preferring and non-menthol-preferring smokers.

METHODS

Nicotine dependent participants (N = 134) participated in an intravenous nicotine delivery session following overnight smoking abstinence. Participants were intravenously administered a placebo and 2 escalating nicotine doses. We compare subjective and physiological responses to nicotine and smoking urges, withdrawal, and cognitive performance following overnight abstinence and post-nicotine between regular 'menthol' smokers and 'non-menthol' cigarette smokers.

RESULTS

Relative to non-menthol-preferring smokers, menthol-preferring smokers re a smaller reduction in smoking urges from overnight abstinence baseline to post-nicotine end-of-session and rated less subjective differences between nicotine doses.

CONCLUSIONS

Differences between menthol-preferring and non-menthol-preferring smokers' responses to abstinence or acute nicotine could reflect pre-existing individual differences that may have in initial development of menthol preferences, or could have arisen secondarily to pro use of menthol versus non-menthol cigarettes.