The reliability of puff topography and subjective responses during ad lib smoking of a single cigarette

Long-term effects of chronic exposure to electronic cigarette aerosol on the cardiovascular and pulmonary system in mice: A comparative study to cigarette smoke

Electronic cigarettes (e-cigarettes) have rapidly gained popularity as alternatives to traditional combustible cigarettes. However, their long-term health impact remains uncertain. This study aimed to investigate the effects of chronic exposure to e-cigarette aerosol (ECA) in mice compared to conventional cigarette smoke (CS) exposure. The mice were exposed to air (control), low, medium, or high doses of ECA, or a reference CS dose orally and nasally for eight months. Various cardiovascular and pulmonary assessments have been conducted to determine the biological and prosthetic effects. Histopathological analysis was used to determine structural changes in the heart and lungs. Biological markers associated with fibrosis, inflammation, and oxidative stress were investigated. Cardiac proteomic analysis was applied to reveal the shared and unique protein expression changes in ECA and CS groups, which related to processes such as immune activation, lipid metabolism, and intracellular transport. Overall, chronic exposure to ECA led to adverse cardiovascular and pulmonary effects in mice, although they were less pronounced than those of CS exposure. This study provides evidence that e-cigarettes may be less harmful than combustible cigarettes for the long-term health of the cardiovascular and respiratory systems in mice. However, further human studies are needed to clarify the long-term health risks associated with e-cigarette use.

The Role of Nicotine Metabolic Rate on Nicotine Dependence and Rewarding: Nicotine Metabolism in Chinese Male Smokers and Male Mice

The exact relationship between nicotine metabolism and dependence is not fully understood but is known to be influenced at a molecular level by genetic factors. A sample comprising 274 Chinese adult male smokers was categorized into groups based on their metabolic rates, namely fast, intermediate, and slow metabolizers. We then measured their smoking topography, evaluated their nicotine dependence, and assessed the rewarding effects. Based on these findings, we proposed the hypothesis that the rate of nicotine metabolism could influence the level of dopamine release which in turn had repercussions on the pleasurable and rewarding effects. To test this hypothesis, male mice were selected with different nicotine metabolic rates that closely resembled in the smoker group. We evaluated their nicotine dependence and rewarding effects through conditioned place preference and withdrawal symptom tests, supplemented with dopamine release measurements. In both animal and human, the slow metabolism group (SMG) required less nicotine to maintain a comparable level of dependence than the fast metabolism group (FMG). The SMG could achieve similar rewarding effects to FMG despite consuming less nicotine. Comparable dopamine levels released were therefore critical in setting the nicotine acquisition behavior in this animal model and also for the smokers tested. Our findings suggested that even within the same ethnicity of established smokers (Chinese Han), differences in nicotine metabolism were an important parameter to modulate the degree of nicotine dependence.

Biochemical validation of self-reported electronic nicotine delivery system and tobacco heaviness of use

Research on tobacco use disorder relies on a combination of self-reported use (e.g., cigarettes per day) and biochemical validation to quantify heaviness of use. However, electronic nicotine delivery system (ENDS) users may be unaware of how much they have vaped per day. The aim of this study was to test the relationship between self-reported heaviness of ENDS/tobacco use and nicotine biomarkers. Young adults (n = 30) who currently use ENDS and other tobacco products completed a detailed tobacco use history, timeline follow-back, and an ENDS topography session. We evaluated the self-reports of own-brand ENDS use and tested correlations to determine which self-report measures of own-brand use, and which self-reported measures of puff topography, had the strongest correlations with urine and/or blood biomarkers of nicotine use. Participants reported using a variety of different ENDS devices and had a range of usage. The sum of the self-reported number of occasions or hours of ENDS use, along with the number of cigarettes and other tobacco products used, over the past 24 hr was significantly correlated with plasma cotinine levels. Puff topography measures correlated with increased nicotine concentrations, although participants underestimated the number of puffs they took during the topography session. This study provides preliminary evidence that summing together the hours of ENDS use, or the number of occasions of ENDS use, in addition to the number of other tobacco products used (i.e., cigarettes) based on self-report may be an accurate method of quantification. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Difficulties in emotion regulation and ad libitum smoking topography: A secondary analysis

INTRODUCTION

Despite the well-known linkages between poor emotion regulation and subjective smoking motives, little is known about the role of emotion regulation in predicting smoking reinforcement behavior. This study examined the relation between difficulties in emotion regulation and puff velocity data, a behavioral index of smoking reinforcement, in adult daily cigarette smokers.

METHOD

The current study was a secondary analysis of data collected from non-treatment seeking daily smokers (N = 124). Participants completed the Difficulties in Emotion Regulation Scale (DERS) followed by an ad libitum smoking period during which puff topography data was collected via a handheld puffing device. Puff velocity served as our puff topography index and was examined at the average and puff-to-puff level using regression and multi-level models, respectively.

RESULTS

Regression analyses showed no significant association between DERS scores and average puff velocity. In contrast, multi-level modeling found a significant quadratic time × DERS effect at the puff-to-puff level, such that those with greater emotion regulation difficulties inhaled more quickly at the initiation of the cigarette, whereas those with lower emotion regulation difficulties evidenced consistent puffing over the course of the cigarette.

DISCUSSION

Smokers with greater difficulties in emotion regulation appear to smoke in a way that maximizes delivery of nicotine, perhaps to self-regulate distress. One's style of puffing may reflect a possible behavioral marker of negative reinforcement smoking, especially in the context of emotional distress.

IMPLICATIONS

This study was the first to explore the relationship between difficulties in emotion regulation and a behavioral measure of smoking reinforcement.

Analyzing Impact of Mouthpiece-based Puff Topography Devices on Smoking Behavior using Wearable Sensors

Detailed assessment of smoking topography (puffing and post-puffing metrics) can lead to a better understanding of factors that influence tobacco use. Research suggests that portable mouthpiece-based devices used for puff topography measurement may alter natural smoking behavior. This paper evaluated the impact of a portable puff topography device (CReSS Pocket) on puffing & post-puffing topography using a wearable system, the Personal Automatic Cigarette Tracker v2 (PACT 2.0) as a reference measurement. Data from 45 smokers who smoked one cigarette in the lab and an unrestricted number of cigarettes under free-living conditions over 4 consecutive days were used for analysis. PACT 2.0 was worn on all four days. A puff topography instrument (CReSS pocket) was used for cigarette smoking on two random days during the four days of study in the laboratory and free-living conditions. Smoke inhalations were automatically detected using PACT2.0 signals. Respiratory smoke exposure metrics (i.e., puff count, duration of cigarette, puff duration, inhale-exhale duration, inhale-exhale volume, volume over time, smoke hold duration, inter-puff interval) were computed for each puff/smoke inhalation. Analysis comparing respiratory smoke exposure metrics during CReSS days and days without CReSS revealed a significant difference in puff duration, inhale-exhale duration and volume, smoke hold duration, inter-puff interval, and volume over time. However, the number of cigarettes per day and number of puffs per cigarette were statistically the same irrespective of the use of the CReSS device. The results suggested that the use of mouthpiece-based puff topography devices may influence measures of smoking topography with corresponding changes in smoking behavior and smoke exposure.

Impact of smoked cannabis on tobacco cigarette smoking intensity and subjective effects: A placebo-controlled, double-blind, within-subjects human laboratory study

Co-users of cannabis and tobacco frequently use cannabis, then tobacco cigarettes, in a sequential pattern within an occasion, that is, they "chase" smoked cannabis with a tobacco cigarette. The objective of this placebo-controlled, double-blind, within-subjects human laboratory study was to gather preliminary data on how smoking active versus placebo cannabis impacts tobacco cigarette smoking behavior, craving, and subjective effects. Adult daily cannabis and tobacco co-users (N = 9) were randomly assigned to two experimental visit orders (i.e., active cannabis (5.2% THC) first visit and placebo cannabis second visit, or vice versa). Participants smoked one cannabis cigarette, and approximately 30 min later were given a 5-min ad libitum period to smoke one of their own brand of tobacco cigarette. As expected, boost in plasma THC levels and cannabis-related subjective effects differed between active and placebo cannabis conditions. Tobacco cigarette puff topography measures and tobacco craving did not differ between cannabis conditions, but there appeared to be between-participants heterogeneity in cumulative total puff volume. After smoking active versus placebo cannabis, the changes in subjective effects of tobacco smoking after adjusting for pretobacco smoking levels were not significant. Results do not support the notion that immediate effects of smoked cannabis change the behavior of tobacco smoking. The strong overlap between cannabis and tobacco smoking may not be explained by primarily pharmacological factors, but may be driven by more nuanced and complex mechanisms involving pharmacological processes as well as learning factors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Comparing video observation to electronic topography device as a method for measuring cigarette puffing behavior

BACKGROUND

Smoking topography, or puffing behavior, is an important measure of how consumers may use tobacco products. However, numerous issues may prevent collection of this data via in-person, electronic topography device (e.g., CReSS). This study compared cigarette topography measures collected by video observation and electronic device.

METHODS

Laboratory smoking sessions were video recorded and scored for 96 cigarettes collected from 34 daily, adult non-treatment-seeking smokers (73.5 % male, 82.4 % White). Participants smoked three of their preferred brand cigarettes using an electronic topography device, providing carbon monoxide (CO) samples before and after each cigarette. Analyses compared measures from both assessment methods and examined associations with device-obtained total puff volume and CO boost.

RESULTS

Agreement analyses indicated robust similarity between methods for measures of puff count and total interpuff interval (Intraclass Correlation Coefficient [ICC]'s > 0.96,p's < 0.001; Bland-Altman [B-A] plotted differences within a priori limit of clinical significance) but diverged on total duration (ICC's > .93, p's < .001, yet B-A plots outside a priori limits). Regardless of assessment method, total duration and puff count (but not total interpuff interval) predicted total puff volume (p's < .001). None predicted CO boost (p's = .07-.90)."

CONCLUSIONS

Although some topography outcomes (e.g., total puff volume) cannot be assessed via video observation, video-observed measures of puff count, total duration, and total interpuff interval are generally interchangeable with their topography device-obtained counterparts. Thus, video observation is likely a sufficient substitute method for assessing cigarette topography when using an electronic device is not possible.

A Forced-Choice Procedure to Assess the Acute Relative Reinforcing Effects of Nicotine Dose per se in Humans

INTRODUCTION

A method to assess acute reinforcement due to nicotine may aid identification of doses needed to maintain dependence. After describing development of a forced-choice procedure, results are presented from two studies using it to determine the relative reinforcing effects of nicotine dose per se.

AIMS AND METHODS

Choice between a higher versus a very low or no nicotine option, via smoking (Study 1, n = 59) and via nasal spray (Study 2, n = 42), was assessed in nontreatment-seeking dependent smokers abstinent overnight. Using a within-subject design, different nicotine levels for each product were administered under blind conditions, initially to assess their discriminability (Study 1: 1.3-17 mg/g each vs. 0.4 mg/g nicotine Spectrum cigarettes; Study 2: 2.5 µg/kg vs. 0 µg/kg nicotine per spray). At the end of sessions for each study, participants engaged in forced-choice trials to assess preference, requiring a fixed number of puffs/sprays for one and/or the other.

RESULTS

Confirming the procedure's validity, the choice of the higher nicotine option was significantly greater than that for the very low or no nicotine option in both studies. In Study 1, choice relative to 0.4 mg/g was greater for cigarettes 5.3 mg/g or more but not 2.3 mg/g or less (p = .003 for the interaction of higher content vs. 0.4 mg/g comparison). In Study 2, choice was greater for the nicotine versus placebo spray (p < .005), as nicotine was preferred nearly twice as much as the placebo.

CONCLUSION

This forced-choice procedure may efficiently determine the relative reinforcing value of a nicotine dose per se.

IMPLICATIONS

The forced-choice procedure described here may identify nicotine doses that are acutely reinforcing in dependent smokers. A priori research of choice comparisons between small versus zero nicotine doses could inform clinical research in larger and more diverse samples to determine nicotine contents in cigarettes, and perhaps in other commercial products, that are not reinforcing and, thus, likely to reduce the risk of their addictiveness. This procedure may also be applicable to assessing changes in acute nicotine reinforcement due to different product formulations, novel drugs, or other manipulations, perhaps helping inform development of new interventions for cessation or harm reduction.

Reminders of a Stigmatized Status Might Help Smokers Quit

As members of a devalued group, it is not surprising that smokers experience stigmatization and discrimination. But it is not clear if smokers react to these experiences by moving toward or away from their group membership and identity as smokers. Guided by the identity threat model of stigma (Major and O'Brien, 2005) we examined the process of stigmatization and its emotional, cognitive, attitudinal, and behavioral consequences. We experimentally examined how reading a stigmatizing newspaper article or a control article (Experiment 1) and recalling one's experience with smoking discrimination or a control prompt (Experiment 2) affected smokers' responses. We also examined the role of cultural contexts (U.S. vs. Denmark; only in Experiment 1) and smoking identity. In Experiment 1, we used a community sample of smokers from the U.S. (N = 111) and Denmark (N = 111). We found that reading the stigmatizing article (compared to the control) caused more rejection sensitivity (U.S. participants only) and more intentions to quit smoking (both U.S. and Danish participants) for smokers low in smoking identity. In Experiment 2, we used an online sample of 194 U.S. smokers and found that recalling instances of mistreatment made smokers more stressed, rejection sensitive, and interested in smoking cessation, when smokers appraised the stigma cue as threatening. Thus, we generally found that identity threat moved smokers toward leaving their stigmatized group (e.g., quitting smoking) rather than away from it. Our studies highlight the importance of understanding psychological process by which smokers distance themselves from their spoiled identity.

Differences in acute reinforcement across reduced nicotine content cigarettes

RATIONALE

The smallest difference in nicotine that can change a smoker's cigarette preference is not clearly known.

OBJECTIVE

A procedure to efficiently identify the difference in nicotine needed to change cigarette preference could help inform research to gauge effects of a nicotine reduction policy.

METHODS

Using a within-subject design, we assessed preference for research cigarettes varying in nicotine contents (NIC; 18.7, 10.8, 5.3, 2.3, and 1.3 mg/g of tobacco), relative to a very low nicotine cigarette (VLNC; 0.4 mg/g), in 17 adult-dependent non-menthol smokers abstinent overnight. Only one NIC was compared vs. the VLNC per session, with order of the five NIC contents randomized across sessions on five separate days. Preference for each NIC vs. VLNC was determined by validated forced choice procedure, with those NIC chosen more than VLNC indicating greater reinforcement due to greater nicotine per se. Secondarily, less preference for lower NIC (vs. VLNC), relative to choice for the highest NIC, 18.7 mg/g (vs. VLNC), indexed reduced reinforcement.

RESULTS

Overall, NIC choices increased as their nicotine increased, as anticipated. Relative to the 0.4 mg/g VLNC, choice was greater for NIC ≥ 5.3 mg/g but not ≤ 2.3 mg/g. Correspondingly, relative to choice for 18.7 mg/g, choice was less for NIC ≤ 2.3 mg/g but not ≥ 5.3 mg/g.

CONCLUSIONS

Although replication with larger samples and longer access is needed, results indicate that nicotine reduction to ≤ 2.3 mg/g in cigarettes would attenuate reinforcement. This choice procedure may efficiently inform future clinical trials to assess relative reinforcing effects of smoking reduced nicotine cigarettes.

Characteristic Human Individual Puffing Profiles Can Generate More TNCO than ISO and Health Canada Regimes on Smoking Machine When the Same Brand Is Smoked

Human smoking behavior influences exposure to smoke toxicants and is important for risk assessment. In a prospective observational study, the smoking behavior of Marlboro smokers was measured for 36 h. Puff volume, duration, frequency, flow and inter-puff interval were recorded with the portable CReSSmicro™ device, as has often been done by other scientists. However, the use of the CReSSmicro™ device may lead to some registration pitfalls since the method of insertion of the cigarette may influence the data collection. Participants demonstrated consistent individual characteristic puffing behavior over the course of the day, enabling the creation of a personalized puffing profile. These puffing profiles were subsequently used as settings for smoking machine experiments and tar, nicotine and carbon monoxide (TNCO) emissions were generated. The application of human puffing profiles led to TNCO exposures more in the range of Health Canada Intense (HCI)-TNCO emissions than for those of the International Standardization Organization (ISO). Compared to the ISO regime, which applies a low puff volume relative to human smokers, the generation of TNCO may be at least two times higher than when human puffing profiles were applied on the smoking machine. Human smokers showed a higher puffing intensity than HCI and ISO because of higher puffing frequency, which resulted in more puffs per cigarette, than both HCI and ISO.

A Procedure to Standardize Puff Topography During Evaluations of Acute Tobacco or Electronic Cigarette Exposure

INTRODUCTION

Documenting factors that influence differential sensitivity to acutely inhaled nicotine products requires carefully controlling the amount of exposure (dose), and thus a procedure by which to control such exposure.

METHODS

We evaluated consistency of puff volume from intermittent acute exposures to smoked tobacco cigarettes (study 1, n = 45, plus a comparison study of uninstructed use with n = 59) and to vaped electronic cigarettes (e-cigarettes; study 2, n = 27 naive to e-cigarettes) in adult-dependent smokers. All in primary studies 1 and 2 participated in research administering different nicotine levels in each product under blind conditions, one per session using within-subject designs. In both studies, participants followed an automated instructional procedure on a computer monitor standardizing the timing and amount of exposure to each product during a given trial, with four trials per session, each separated by 20 minutes. Puff volume per trial via Clinical Research Support System (CReSS) was the primary dependent measure to determine consistency across trials via intraclass correlation coefficients (ICCs).

RESULTS

Control over topography with both inhaled products was demonstrated by highly significant ICCs for puff volume across trials. Instructed control with own brand was generally better in study 1 than with uninstructed smoking in the comparison sample, as expected. As intended, reliability of puff volume generally did not differ by menthol preference or sex in either study, but ICCs in study 2 tended to be lower for some men using the placebo e-cigarette.

CONCLUSIONS

This instructional procedure may substantially improve control over amounts of acute exposure to tobacco or e-cigarette use.

IMPLICATIONS

Control over topography in studies of acute exposure to these inhaled products can potentially aid validity of research into differential sensitivity to use, so findings can be attributed to factors of interest and not to variable exposure. Our procedure minimized variability in exposure to the same product and between moderate nicotine products, but remaining differences suggest that compensation for very low or no nicotine commercial products may be difficult to totally eliminate with these instructions alone. Further study is needed to determine this procedure's utility with other inhaled products among experienced users and when comparing different products in between-groups analyses.

Distress Intolerance and Smoking Topography in the Context of a Biological Challenge

INTRODUCTION

Distress intolerance (DI), one's perceived or behavioral incapacity to withstand distress, is implicated in psychopathology and smoking. This study evaluated the effect of DI on smoking reinforcement in the context of a carbon dioxide (CO2) biological challenge.

METHODS

Adult daily smokers (n = 90; 48.9% female) were randomized to receive a single inhalation/breath of 35% CO2-enriched air (n = 45) or compressed room air (n = 45). Perceived DI was assessed before the challenge. Smoking reinforcement was examined via average post-challenge puff volume across puffs and at the puff-to-puff level.

RESULTS

Higher DI was associated with an increased average puff volume (b = -4.7, p = .031). CO2 produced decreased average puff volume compared with room air (b = -7.7, p = .018). There was a DI* condition interaction (ƒ2 = 0.02), such that CO2 decreased average puff volume compared with room air in smokers with higher DI (b = -13.9, t = -3.06, p = .003), but not lower DI. At the puff-to-puff level, there was a significant interaction between DI, condition, and cubic time (b = 0.0003, p =. 037). Specifically, room air produced large initial puff volumes that decreased from puff to puff over the cigarette for high- and low-DI smokers. CO2 produced persistent flat volumes from puff to puff over the cigarette for higher DI smokers, whereas CO2 produced puff volumes like that of room air in lower DI smokers.

DISCUSSION

Findings suggest DI heightens smoking reinforcement generally, and in the context of intense cardiorespiratory distress, is associated with stable and persistent smoking. DI is a promising therapeutic target that, if addressed through psychological intervention, may improve cessation outcomes by decreasing smoking reinforcement.

IMPLICATIONS

This study contributes to our understanding of the relationship between DI and smoking reinforcement, via examining these processes in response to acute cardiorespiratory distress. Specifically, we found that smokers who are less tolerant of distress, as opposed to those who are more tolerant, evince a decrease in average puff volume, and consistently low puff-to-puff volume, in response to a biological stressor. These findings suggest that smokers high in DI alter smoking behavior following acute cardiorespiratory distress, perhaps to reduce overstimulation, yet also persist in smoking in a manner that suggests an inability to achieve satiation.

Examination of a mouthpiece-based topography device for assessing relative reinforcing effects of e-cigarettes: A preliminary study

The assessment of vaping topography has helped to identify characteristics associated with distinct vaping patterns. Available puff topography devices do not alter the subjective effects of vaping. However, one central construct related to drug abuse, unexplored in prior studies, is whether relative reinforcing effects (RRE) of vaping change when using a topography device. We examined the RRE of vaping when individuals vape through an e-cigarette with a mouthpiece topography device attached versus their own e-cigarette. Associations of demand indices for participants' own e-cigarette and for a research e-cigarette with a topography device were also explored. Forty-three e-cigarette users attended 1 experimental session where they completed 2 purchase tasks in different units of consumption, ml and puffs, with their preferred e-cigarette and with an e-cigarette with a mouthpiece. Puff topography was measured in the mouthpiece condition. All four purchase tasks showed the predicted inverse relationship between purchase and price. No differences in most demand indices were observed between both e-cigarettes, except for breakpoint (lowest price that suppresses consumption) and Omax (maximum expenditure) in ml units which both decreased when participants vaped through the mouthpiece device. Demand indices in ml units were more strongly associated. Data from the purchase tasks suggests that the presence of a mouthpiece topography device does not influence the RRE of vaping among e-cigarette users. Demand for e-cigarettes seems more consistent in ml units. Our results further evidence that mouthpiece topography devices represent a valid and reliable instrument to study RRE of e-cigarettes and, by extension, abuse liability. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The influence of gender and oxytocin on stress reactivity, cigarette craving, and smoking in a randomized, placebo-controlled laboratory relapse paradigm

RATIONALE

Female cigarette smokers tend to show greater cessation failure compared with males. Variables that contribute to the maintenance of smoking, including stress and craving, may differentially impact male and female smokers. Novel pharmacotherapies, such as oxytocin, may attenuate stress reactivity and craving in smokers, but work in this area is limited.

OBJECTIVES

This study assessed the influence of gender and oxytocin on stress reactivity, craving, and smoking in a randomized, placebo-controlled laboratory relapse paradigm.

METHODS

Male and female adult cigarette smokers (ages 18-45) were enrolled (women oversampled 2:1) and completed a laboratory session, in which intranasal oxytocin or placebo was administered followed by a laboratory social stress task. The role of gender and oxytocin were assessed on measures of stress reactivity, cigarette craving, latency to smoke in a resistance task, subjective responses to smoking, and ad-libitum smoking.

RESULTS

Participants (N = 144) had a mean age of 31 were 63% female and 56% White. Following stress induction, female smokers evidenced greater subjective stress than males, though males demonstrated greater neuroendocrine reactivity and smoking intensity than females. No gender differences were demonstrated for craving. Oxytocin did not attenuate any aspect of stress reactivity, craving, smoking, or subjective responses to smoking compared with placebo.

CONCLUSIONS

Gender differences in stress reactivity were shown in the hypothesized direction, but oxytocin appeared to exert little impact on subjective or behavioral metrics. Results highlight the complex relationship between gender, stress, and smoking, as well as the implications for oxytocin as a potential pharmacotherapy for smoking cessation.

Negative urgency and ad-libitum smoking topography

BACKGROUND

Negative urgency (NU), the tendency to act rashly in response to distress, is associated with negative reinforcement smoking expectancies. The study examined whether NU was associated with behavioral smoking reinforcement in the context of self-reported distress.

METHOD

Non-treatment seeking daily smokers (n = 124) completed an ad-libitum smoking trial. Puff topography, including puff volume, duration, velocity, and inter-puff interval, was averaged across the cigarette and evaluated at the puff level.

RESULTS

Multilevel models revealed a significant interaction of NU and distress as reported on the Subjective Units of Distress scale over the course of smoking in relation to puff duration and inter-puff interval. There was a significant effect of quadratic time x NU x distress on duration (b=-0.00004, p = 0.04). Smokers lower in NU reporting lower baseline distress evidenced a puff duration that decreased at a faster rate over the course of a cigarette following a quadratic function. Persistently elevated puff durations over the course of a cigarette were observed among smokers with elevated NU, regardless of basal distress. There was also a linear time x NU x distress interaction on inter-puff interval (b=-0.01, p = 0.04). Lower NU smokers, regardless of acute distress, exhibited increasing inter-puff intervals that stabilized over the course of a cigarette. Smokers with elevated NU in the context of low distress also demonstrated linearly increasing inter-puff intervals, while they demonstrated increasing intervals followed by decreasing intervals in the context of higher distress.

DISCUSSION

Trait NU in the context of acute distress may contribute to differences in puff topography.

Sex Differences in Subjective Responses To Moderate Versus Very Low Nicotine Content Cigarettes

Introduction

Men and women may be differentially sensitive to the acute perceptual responses to smoking cigarettes that vary in nicotine content ("dose") but are matched on non-nicotine constituents.

Methods

Dependent adult smokers (43 M, 31 F) took four controlled puffs from Spectrum research cigarettes that were moderate (16-17 mg/g) or very low (0.4 mg/g) in nicotine content, and matched on "tar." To ensure reliable responses, each cigarette was administered singly five times in random order under blind conditions, with one or the other provided every 15 minutes over a 2.5-hour session following overnight abstinence. Subjective perceptions (eg, "satisfying", "how much nicotine") were rated after each cigarette.

Results

Subjective ratings differed due to cigarette nicotine content, as expected, and did so differentially between men and women. The interaction of nicotine content by sex was significant for most rated subjective perceptions of the cigarette, as multivariate analyses showed that differences due to nicotine content were highly significant for men (p < .001) but only marginal for women (p = .08).

Conclusions

Relative to men, women's subjective responses to acute smoking are less sensitive to differences in cigarette nicotine content. To our knowledge, this is the first comparison of sex differences in response to very carefully controlled doses of smoked nicotine per se. Further research should examine possible sex differences in nicotine dosing administered by other smoked and nonsmoked methods, as well as the developmental pattern of these differences during onset and during cessation of dependent smoking.

Implications

Subjective perceptions of smoking cigarettes varying in nicotine contents differ between men and women. These results with research cigarettes are similar to other studies with carefully dosed nicotine administration by other means, supporting the notion that women, relative to men, are less sensitive to pharmacological factors and more sensitive to nonpharmacological factors in acute cigarette smoking. Future studies are warranted to examine sex differences in other responses to controlled nicotine intake via smoking, and via other smoked and nonsmoked methods of administering nicotine doses.

Acute perceptions of preferred cigarettes when blinded to brand

Background

Marketing claims often have promoted specific perceptions that users should expect from acutely smoking that cigarette brand. Yet, little controlled study has determined the degree to which actual perceptions are based on the cigarette’s tobacco constituents in the absence of knowledge about the brand’s identity.

Methods

194 adult dependent smokers rated their perceptions on ‘liking’, ‘satisfying’, ‘strong’ and perceived amount of ‘nicotine’ after smoking ad lib one of their preferred brands of cigarettes. All did so either when blinded (n=118) or unblinded (n=76) to the brand they were given, with the blinding conditions from separate studies. These between-groups secondary analyses determined differences in perceptions based on blinding to brand, controlling for age and cigarettes/day.

Results

All perceptions were lower for those smoking own brand under blinded versus unblinded conditions, as hypothesised. Consistent with lowered perceptions for smoking one’s own brand obtained from the 118 blinded to brand, their ‘somewhat’ ratings for a ‘how similar to own brand’ item indicated uncertainty, just mid-way between ‘not at all’ and ‘very much’ on the 0–100 visual analogue scale. (The 76 unblinded were already informed it was their own brand.)

Conclusions

Acute perceptions of one’s own cigarette are substantially lower when smokers are simply unaware of brand, relative to those aware it is their preferred brand. Results support the notion that perceptions of smoking own brand are enhanced by marketing efforts to associate brands with expectations of pleasurable subjective effects, beyond the impact due solely to the cigarette’s manufactured product constituents.

Cigarillo and Little Cigar Mainstream Smoke Constituents from Replicated Human Smoking

Little cigar and cigarillo smoking is increasing in popularity in the U.S., but little is known about the topography and mainstream smoke (MSS) constituents of these types of cigar products. This report describes the quantity of selected MSS toxicants generated from puff-by-puff replication of human laboratory smoking. Participants were dual users of cigarettes and either little cigars ( n = 21) or cigarillos ( n = 23). In the laboratory smoking session, participants of the little cigar group smoked a filtered unflavored Winchester Little Cigar; those in the cigarillo group smoked an unfiltered, unflavored Black & Mild cigarillo. MSS components included both volatiles and semivolatile compounds. The MSS of five representative U.S. domestic cigarettes was generated using smoking topography profiles of the participants smoking their own brand of cigarettes. Machine smoking accurately replicated individual puff profiles as indicated by a high correlation between lab and machine smoked: time to smoke, number of puffs, and total puff volume. There was wide variability in smoking patterns across subjects of both little cigars and cigarillos. For example, total puff volume ranged from 84 to 732 mL after the little cigar and from 270 to 2089 mL after the cigarillo. Qualitatively, cigar smoke from little cigars and cigarillos were similar and resembles cigarette smoke. All analytes (VOC and SVOCs) were greater in cigarillo smoke compared to that of little cigars and cigarettes. However, when the toxicants were adjusted for grams of tobacco burned, little cigar smoke contained more nicotine, tobacco-specific nitrosamines, acetonitrile, and acrylonitrile compared with cigarillo smoke. When the constituents were adjusted for nicotine content, cigarillo MSS contained more of all toxicants compared with little cigar. Cigarillos and little cigars, like cigarettes, deliver nicotine and other toxicants known to be harmful to health; their regulation by the FDA is appropriate for their public health risk.

Evaluation of menthol per se on acute perceptions and behavioral choice of cigarettes differing in nicotine content

Subjective perceptions and self-administration of cigarettes are each influenced by nicotine. Yet, differences specifically due to menthol in perceptions and choice of cigarettes varying in nicotine, and the association between these responses, have not been directly tested. Using a mixed between- and within-subjects design, acute responses to each of two menthol or non-menthol Spectrum research cigarettes, moderate (16-17 mg/g) versus very low (0.4 mg/g) in nicotine contents, were compared following brief abstinence in adult smokers preferring menthol ( n=44) or non-menthol ( n=29) brands. To ensure reliable perceptions, they experienced five exposures to each cigarette, then chose between them. All perceptions and choices were greater for moderate vs very low nicotine, as expected, and the magnitude of difference in four of six perceptions was associated with subsequently greater choice of the moderate nicotine cigarette. Importantly, virtually no differences were found between menthol and non-menthol, as nearly all perceptions, cigarette choices, and the association between perceptions and choice were not moderated by menthol or the interaction of nicotine by menthol. Our results indicate perceptions and reinforcement from cigarettes do not differ due to menthol when nicotine content and smoking topography are carefully controlled. Thus, regardless of menthol, smoking perceptions directly predict self-administration behavior.

Tobacco demand, delay discounting, and smoking topography among smokers with and without psychopathology

INTRODUCTION

Tobacco demand (i.e., relative value attributed to a given reinforcer) and delay discounting (i.e., relative preference for smaller immediate rewards over larger delayed rewards) are two behavioral economic processes that are linked to the progression of problematic substance use. These processes have not been studied among those with psychopathology, a vulnerable group of smokers. The current study examined differences in tobacco demand and delay discounting, and their association with smoking topography among smokers with (n=43) and without (n=64) past-year psychopathology.

METHOD

Adult daily smokers (n=107,Mage=43.5; SD=9.7) participated in a study on "smoking behavior." Past-year psychological disorders were assessed via a clinician-administered diagnostic assessment. All subjects participated in an ad libitum smoking trial and then completed an assessment of delay discounting (Monetary Choice Questionnaire) and tobacco demand (Cigarette Purchase Task) approximately 45-60min post-smoking.

RESULTS

Smokers with psychopathology, compared to those without, had significantly higher demand intensity and maximum expenditure on tobacco (Omax), but did not differ on other demand indices or delay discounting. Smokers with psychopathology had shorter average inter-puff intervals and shorter time to cigarette completion than smokers without psychopathology. Tobacco demand and delay discounting measures were significantly intercorrelated among smokers with psychopathology, but not those without. Both behavioral economic measures were associated with specific aspects of smoking topography in smokers with psychopathology.

DISCUSSION

The association between tobacco demand and delay discounting is evident among smokers with psychopathology and both measures were most consistently related to smoking behavior.

Second-hand smoke generated by combustion and electronic smoking devices used in real scenarios: Ultrafine particle pollution and age-related dose assessment

Aerosol measurements were carried out in a model room where both combustion (conventional and hand-rolled cigarettes, a cigar and tobacco pipe) and non-combustion (e-cigarette and IQOS®) devices were smoked. The data were used to estimate the dose of particles deposited in the respiratory systems of individuals from 3months to 21years of age using the multiple-path particle dosimetry (MPPD) model. Regardless of the smoking device, the highest doses were received by infants, which reached 9.88×10⁸particles/kg bw during a cigar smoking session. Moreover, 60% to 80% of the particles deposited in the head region of a 3-month-old infant were smaller than 100nm and could be translocated to the brain via the olfactory bulb. The doses due to second-hand smoke from electronic devices were significantly lower, below 1.60×10⁸particles/kg bw, than those due to combustion devices. Dosimetry estimates were 50% to 110% higher for IQOS® than for e-cigarettes.

Effects of nicotine versus placebo e-cigarette use on symptom relief during initial tobacco abstinence

Because electronic cigarettes (e-cigs) containing nicotine may relieve smoking abstinence symptoms similar to nicotine replacement therapy medication, we used within-subjects designs to test these effects with a first-generation e-cig in nonquitting and quitting smokers. In Study 1, 28 nontreatment-seeking smokers abstained overnight prior to each of 3 sessions. Minnesota Nicotine Withdrawal Scale (MNWS) withdrawal (and craving item) relief was assessed following 4 exposures (each 10 puffs) over 2 hr to e-cigs that either did (36 mg/ml) or did not (i.e., placebo, 0 mg/ml) contain nicotine or after no e-cig. Relief was greater after nicotine versus placebo e-cig (p < .05) but not after placebo versus no e-cig, showing relief was due to nicotine per se and not simple e-cig use behavior. Using a crossover design in Study 2, smokers preparing to quit soon engaged in 2 experimental 4-day quit periods on separate weeks. In weeks 1 and 3, all received a nicotine or placebo e-cig on Monday to use ad libitum while trying to abstain from smoking on Tuesday through Friday. (Week 2 involved resumption of ad libitum smoking.) MNWS and Questionnaire of Smoking Urges (QSU) craving were assessed at daily visits following 24-hr abstinence. Of 17 enrolled, 12 quit for ≥24 hr at least once, allowing test of relief because of e-cig use on quit days. Withdrawal and craving were reduced because of nicotine versus placebo e-cig use (both p < .05). In sum, compared with placebo e-cigs, nicotine e-cigs can relieve smoking abstinence symptoms, perhaps in a manner similar to Food and Drug Administration-approved nicotine replacement therapy products, although much more research with larger samples is needed. (PsycINFO Database Record

Preliminary test of cigarette nicotine discrimination threshold in non-dependent versus dependent smokers

BACKGROUND

Despite its potential for understanding tobacco dependence, behavioral discrimination of nicotine via smoking has not been formally examined as a function of nicotine dependence level.

METHODS

Spectrum research cigarettes were used to compare non-dependent with dependent smokers on the lowest content of nicotine they could discriminate (i.e., "threshold"). Dependent (n=21; 16M, 5F) or non-dependent (n=7; 4M, 3F) smokers were tested on ability to discriminate between cigarettes with nicotine contents of 17, 11, 5, 2, and 1mg/g, one per session, from an "ultra-low" cigarette with 0.4mg/g (all had 9-10mg "tar"). All abstained from smoking overnight prior to sessions, and number of sessions was determined by the lowest nicotine content they could reliably discriminate from the ultra-low on >80% of trials (i.e., ≥5 of 6). Subjective perceptions and cigarette choice behavior were also assessed and related to discrimination behavior.

RESULTS

Discrimination thresholds (and most perceptions) did not differ between dependent and non-dependent smokers, with median thresholds of 11mg/g for both subgroups. Yet, "liking" and puff choice for threshold cigarettes were greater in dependent but not non-dependent smokers, while cigarettes with nicotine contents below threshold did not support "liking" or choice in both groups.

CONCLUSIONS

In sum, this preliminary study suggests threshold for discriminating nicotine via smoking may not vary by dependence level, and further study is needed to confirm that cigarettes unable to be discriminated are also not reinforcing.

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.

Panic attack history and smoking topography

BACKGROUND

Little is known about panic attacks and puffing topography, a behavioral index of the value of smoking reinforcement. This study examined smoking style during the course of smoking of a single cigarette among adult daily smokers with and without a history of panic attacks.

METHOD

Participants (n=124, M_age=43.9, SD=9.7; 44.4% female) were non-treatment seeking daily smokers. Lifetime panic attack history was assessed via diagnostic assessment; 28.2% (n=35) of the sample had a panic attack history. Participants smoked one cigarette during an ad libitum smoking trial. Puff volume, duration, and inter-puff interval were measured using the Clinical Research Support System (CReSS) pocket device.

RESULTS

Regression analyses revealed that panic attack status was not associated with significant differences in average puff volume, duration, or inter-puff interval. Multi-level modeling was used to examine puffing trajectories. Puff-level data revealed that there was a significant quadratic time x panic effect for puff volume and duration. Those with a panic attack history demonstrated relatively sustained levels of both puff volume and duration over time, whereas those without a history of panic attacks demonstrated an increase followed by a decrease in volume and duration over time. These effects were not accounted for by the presence of general psychopathology.

DISCUSSION

Smokers with a panic attack history demonstrate more persistent efforts to self-regulate the delivery of nicotine, and thus may be at risk for continued smoking and dependence. Tailored treatment may be needed to address unique vulnerabilities among this group.

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.

Relationship between negative affect and smoking topography in heavy drinking smokers

Heavy drinking smokers represent a sizeable subgroup of smokers for whom nicotine deprivation and alcohol use increases the urge to smoke in the laboratory and predicts lapses during smoking cessation. The manner in which individuals smoke a cigarette (i.e. smoking topography) provides a reliable index of smoking intensity and reinforcement, yet the effects of affect on smoking topography have not been thoroughly examined in heavy drinking smokers. The current study examined how affect and nicotine deprivation predict smoking behavior as participants (N=27) smoked one cigarette using a smoking topography device after 12-h of nicotine abstinence and after a priming dose of alcohol (target BrAC=0.06g/dl). Primary smoking topography measures were puff volume, velocity, duration, and inter-puff interval (IPI). The effect of nicotine deprivation was measured by the Minnesota Nicotine Withdrawal Scale (MNWS) and the Profile of Mood States (POMS). Measures were obtained at baseline (i.e. 12-h of nicotine abstinence and pre-alcohol) and 30-minutes after alcohol administration (i.e. peak BrAC). Results revealed post-priming negative affect significantly moderated the trajectories of puff volume, puff duration and IPI (p's<0.05) over the course of the cigarette, such that those with greater negative affect had flatter slopes for volume and duration and increasingly infrequent puffs. Our results suggest that baseline and post-priming negative affect following nicotine deprivation alters smoking patterns and increases nicotine exposure throughout a single cigarette. Future studies need to examine differential amounts of nicotine deprivation on response to alcohol and smoking in heavy drinking smokers.

Assessing Discrimination of Nicotine in Humans Via Cigarette Smoking

INTRODUCTION

Nicotine's interoceptive stimulus effects likely help explain smoking's reinforcing efficacy, but human studies have been limited by difficulties controlling dosing via tobacco inhalation. Our objective was to describe a procedure to study nicotine discrimination via smoking.

METHODS

Dependent smokers abstinent overnight (>12 hours) were first "trained" to discriminate between two cigarettes differing in nicotine content, based on four puffs of exposure, and then tested on whether they successfully acquired that discrimination. After piloting with Quest brand commercial cigarettes, 29 subjects engaged in the main study with cigarettes available through NIDA (Spectrum; 16mg vs. 0.4mg nicotine content). Discrimination training first involved two trials, one with each cigarette, prior to six testing trials. Due to results with the first 20 subjects, the remaining nine received two training trials with each cigarette (four total). Subjective perceptions were also assessed during each testing trial, and puff choice between the two cigarettes available concurrently was assessed after testing, on the last two trials.

RESULTS

All five pilot subjects successfully discriminated Quest 1 versus Quest 3 (defined by at least five out of six trials correct, ie, >80%). Yet, only 10 of 20 subjects (50%) were able to discriminate the two Spectrum cigarettes based on two training trials. After changing to four training trials, eight of nine subjects were able to discriminate (89%). Subjective perceptions and puff choice differed between cigarettes more in those able versus unable to discriminate them.

CONCLUSIONS

With sufficient training exposures, smokers can discriminate nicotine between cigarettes differing in nicotine contents.

IMPLICATIONS

The interoceptive stimulus effects of nicotine are critical to understanding reinforcement from cigarette smoking behavior. Because of the very recent availability of Spectrum research cigarettes from NIDA, with specific known amounts of nicotine content, the study of nicotine discrimination in humans via cigarette smoking may now be feasible. Our results demonstrate that, with sufficient training, smokers can behaviorally discriminate nicotine from four puffs' exposure between cigarettes differing in nicotine contents. Future research should evaluate human discrimination of nicotine from greater amounts of cigarette smoke exposure, as well as in response to other procedural variations.

An experimental test of the effect of acute anxious arousal and anxiety sensitivity on negative reinforcement smoking

INTRODUCTION

Although anxiety sensitivity has been reliably associated with smoking-anxiety comorbidity, there has not been a test of whether this construct moderates the effect of acute anxious arousal on actual smoking behavior. The present study utilized an experimental design to test the moderating role of anxiety sensitivity on laboratory-induced anxious arousal in terms of smoking urges and topography (puff style).

METHOD

Participants were adult daily smokers (n=90; Mage=43.6 SD =9.7); average 15.8 cigarettes per day). A between-subjects design was used; participants were randomly assigned to complete a biological challenge procedure consisting of either a single vital capacity inhalation of 35% carbon dioxide (CO2)-enriched air mixture or compressed room air. Smoking urges and smoking topography (puff behavior) were assessed before and after the challenge.

RESULTS

Results revealed a significant interaction between anxiety sensitivity and experimental condition (b=-9.96, p=0.014), such that high anxiety sensitive smokers exposed to 35% CO2-enriched air reported significantly lower levels of smoking urges, relative to low anxiety sensitive smokers; the conditional effect of anxiety sensitivity was not observed for the room air condition. There were no significant interaction effects of experimental manipulation by anxiety sensitivity for any of the smoking topography outcomes.

DISCUSSION

The present results suggest for smokers with higher levels of anxiety sensitivity, the acute experience of anxious arousal is related to decreased subjective smoking urges. These data invite future research to explore the reasons for dampened smoking urges, including cardiorespiratory symptom severity.

Threshold dose for discrimination of nicotine via cigarette smoking

RATIONALE

The lowest nicotine threshold "dose" in cigarettes discriminated from a cigarette containing virtually no nicotine may help inform the minimum dose maintaining dependence.

OBJECTIVES

Spectrum research cigarettes (from NIDA) differing in nicotine content were used to evaluate a procedure to determine discrimination thresholds.

METHODS

Dependent smokers (n = 18; 13 M, 5 F) were tested on ability to discriminate cigarettes with nicotine contents of 11, 5, 2.4, and 1.3 mg/g, one per session, from the "ultralow" cigarette with 0.4 mg/g, after having discriminated 16 mg/g from 0.4 mg/g (all had 9-10 mg "tar"). Exposure to each was limited to 4 puffs/trial. All subjects were abstinent from smoking overnight prior to each session, and the number of sessions was determined by the participant's success in discrimination behavior on >80 % of trials. Subjective perceptions and behavioral choice between cigarettes were also assessed and related to discrimination behavior.

RESULTS

The median threshold was 11 mg/g, but the range was 2.4 to 16 mg/g, suggesting wide variability in discrimination threshold. Compared to the ultralow, puff choice was greater for the subject's threshold dose but only marginal for the subthreshold (next lowest nicotine) cigarette. Threshold and subthreshold also differed on subjective perceptions but not withdrawal relief.

CONCLUSIONS

Under these testing conditions, threshold content for discriminating nicotine via cigarettes may be 11 mg/g or greater for most smokers, but some can discriminate nicotine contents one-half or one-quarter this amount. Further study with other procedures and cigarette exposure amounts may identify systematic differences in nicotine discrimination thresholds.

The Reliability and Stability of Puff Topography Variables in Non-Daily Smokers Assessed in the Laboratory

INTRODUCTION

Puff topography variables, often measured using the Clinical Research Support System device, have traditionally been studied in regular, daily smokers and have been shown to be highly stable. However, more recent research has focused on non-daily smokers as a population of interest. As such, the aim of this article was to examine puff topography stability (cross-cigarette agreement over time) and reliability (within-cigarette consistency) in non-daily smokers across six laboratory sessions.

METHODS

One hundred seven non-daily smokers attended six laboratory sessions over the course of 3 months. At each session, they smoked one cigarette through the Clinical Research Support System pocket, in addition to completing questionnaires about their smoking history and dependence.

RESULTS

Puff topography measurements were highly reliable (α values ranged from 0.87-0.95) and puff behavior was highly stable across sessions (r values ranged from 0.38-0.84). Adding sessions substantially improved reliability estimates. Aspects of puffing behavior observed in session, including puff volume, puff duration, time of puff peak, and total cigarette volume were related to level of smoke exposure, measured by expired carbon monoxide. Instability in puffing behavior was not predicted by recent or long-term smoking patterns.

CONCLUSIONS

Puff topography appears to be a stable and routinized aspect of smoking in non-daily smokers. The feasibility of assessing puff topography in this population is supported by the high reliabilities observed, though it should be noted that reliability greatly improved by having more than one session.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

IMPACT

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

Waterpipe tobacco smoking: A new smoking epidemic among the young?

Waterpipe (hookah, narghile) tobacco smoking (WTS) is becoming prevalent worldwide and is one of the most popular forms of tobacco use among youth. WTS prevalence has increased dramatically among youth in the United States within the past decade. Misperceived as less harmful than cigarette smoking, WTS is associated with many of the same chronic health effects such as lung cancer, chronic obstructive pulmonary disease, cardiovascular disease, bronchitis, and asthma. Much of this risk is due to the fact that a single WTS session exposes users to large volumes of smoke that contain toxic chemicals such as carbon monoxide, cancer-causing polycyclic aromatic hydrocarbons, and volatile aldehydes. Unlike cigarette smoking, WTS poses unique risks of acute negative health outcomes including carbon monoxide poisoning and the spread of communicable diseases such as herpes and tuberculosis. Because waterpipe tobacco smoke contains the addictive chemical nicotine, youth who smoke tobacco from a waterpipe may be at risk for dependence. As a result, many youth may initiate WTS and continue to use despite negative health effects. Considering many of the potential negative health effects associated with WTS affect the pulmonary system, pulmonologists and primary care providers may treat patients who are waterpipe tobacco smokers and should be aware of the risk associated with WTS. The purpose of this review is to describe a waterpipe, the prevalence and correlates of WTS, the toxicants found in waterpipe tobacco smoke, the health effects of WTS, and implications for pulmonologists and other clinicians.

The Effect of Acute Exercise on Smoking Topography: No Evidence for Cutting Down One Puff at a Time

Recent systematic reviews have concluded that a single session of exercise ameliorates cravings and tobacco withdrawal symptoms; however, smoking behaviour (topography) has not been adequately addressed in the literature. This study examined the effect of an acute bout of exercise on smoking topography following a temporary period of smoking abstinence. Forty-eight adult smokers (Nfemale = 34, Mage = 43.14), who had been smoking for an average of 23.90 years, were randomised to an acute (10 minutes) bout of exercise (N = 23) or passive sitting (control) group. Cigarette cravings were assessed at baseline and immediately pre and post treatment condition during a 15-hour smoking abstinence period. Smoking topography which included puff count, puff volume, puff duration, inter-puff interval, and total cigarette duration was assessed at baseline and post treatment. Although exercise reduced cravings, compared to the control group, smoking topography remained unchanged across time between groups. Furthermore, craving reduction was unrelated to any smoking topography variables. Although there is evidence that exercise can delay time to first cigarette, this study demonstrates that the change to smoking topography is negligible when participants are invited to smoke.

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.

Reinforcement enhancing effects of acute nicotine via electronic cigarettes

BACKGROUND

Recent human studies confirm animal research showing that nicotine enhances reinforcement from rewards unrelated to nicotine. These effects of acute nicotine via tobacco smoking may also occur when consumed from non-tobacco products.

METHODS

We assessed acute effects of nicotine via electronic cigarettes ("e-cigarettes") on responding reinforced by music, video, or monetary rewards, or for no reward (control). In a fully within-subjects design, adult dependent smokers (N=28) participated in three similar experimental sessions, each following overnight abstinence (verified by CO≤10ppm). Varying only in e-cigarette condition, sessions involved controlled exposure to a nicotine (labeled "36mg/ml") or placebo ("0″) e-cigarette, or no e-cigarette use. A fourth session involved smoking one's own tobacco cigarette brand after no abstinence, specifically to compare responses under typical nicotine satiation with these acute e-cigarette conditions after abstinence.

RESULTS

Reinforced responding for video reward, but not the other rewards, was greater due to use of the nicotine versus placebo e-cigarette (i.e., nicotine per se), while no differences were found between the placebo e-cigarette and no e-cigarette conditions (i.e., e-cigarette use per se). For nicotine via tobacco smoking, responding compared to the nicotine e-cigarette was similar for video but greater for music, while both video and music reward were enhanced relative to the non-nicotine conditions (placebo and no e-cigarette).

CONCLUSIONS

Acute nicotine from a non-tobacco product has some reinforcement enhancing effects in humans, in a manner partly consistent with nicotine via tobacco smoking and perhaps contributing to the rising popularity of nicotine e-cigarette use.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPLICATIONS

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

Combined varenicline and naltrexone treatment reduces smoking topography intensity in heavy-drinking smokers

Heavy drinking smokers constitute a distinct sub-population of smokers for whom traditional smoking cessation therapies may not be effective. Recent evidence suggested that combined varenicline (VAR) and naltrexone (NTX) therapy may be more efficacious than either monotherapy alone in reducing smoking and drinking-related behavior in this population. The manner in which individuals smoke a cigarette (i.e., smoking topography) may be predictive of smoking cessation outcomes, yet the effects of smoking pharmacotherapies on puffing behavior have not been thoroughly examined. Therefore, the current double-blind medication study examined the effects of VAR alone (1mg BID), low dose NTX alone (25mg QD), the combination of VAR+NTX, and placebo on smoking topography measures in heavy drinking, non-treatment seeking daily smokers (n=120). After a 9-day titration period, participants completed a laboratory session in which they smoked their first cigarette of the day using a smoking topography device following 12h of nicotine abstinence and consumption of an alcoholic beverage (BrAC=0.06g/dl). The primary measures were puff count, volume, duration, and velocity and inter-puff interval (IPI). Independent of medication group, puff velocity and IPI increased, while puff volume and duration decreased, over the course of the cigarette. The active medication groups, vs. the placebo group, had significantly blunted puff duration and velocity slopes over the course of the cigarette, and this effect was particularly evident in the VAR+NTX group. Additionally, the VAR+NTX group demonstrated lower average IPI than the monotherapy groups and lower average puff volume than all other groups. These results suggest that smoking pharmacotherapies, particularly the combination of VAR+NTX, alter smoking topography in heavy drinking smokers, producing a pattern of less intense puffing behavior. As smoking topography has been predictive of the ability to quit smoking, future studies should examine how smoking pharmacotherapies' effects on puffing behavior relate to smoking cessation outcomes.

Sex differences in acute relief of abstinence-induced withdrawal and negative affect due to nicotine content in cigarettes

INTRODUCTION

Acute cigarette smoking may relieve withdrawal and negative affect due to tobacco abstinence to a greater extent in women versus men. Yet, the relative contribution of the cigarette's nicotine content to this sex difference is not clear.

METHODS

Non-quitting dependent adult smokers (N = 44; 21 males, 23 females) participated in 2 virtually identical sessions, each after abstaining overnight (CO < 10 ppm) and differing only in the nicotine content of the designated cigarette. While blind to brand markings, they consumed a total of 24 puffs in controlled fashion for 2 hr in each session, either from a nicotine (Quest 1, 0.6 mg) or denicotinized (Quest 3, 0.05 mg) cigarette. Withdrawal symptoms were obtained before and after smoking, and negative affect was assessed after each period of cigarette exposure consisting of 6 puffs every 25 min.

RESULTS

Men and women did not differ in baseline withdrawal and negative affect due to overnight abstinence, but reductions in each symptom were significantly influenced by the interaction of sex × nicotine/denicotinized cigarette (both p < .05). In men, but not in women, each symptom was generally decreased more by the nicotine versus denicotinized cigarette, and the nicotine cigarette reduced each to a greater degree in men versus women.

CONCLUSIONS

Sex differences in relief of abstinence-induced withdrawal and negative affect due to the nicotine content in cigarettes are consistent with prior research indicating that nicotine per se, compared to non-nicotine smoke stimuli, is less rewarding in women versus men.

Sensory reinforcement-enhancing effects of nicotine via smoking

As has been found in nicotine research on animals, research on humans has shown that acute nicotine enhances reinforcement from rewards unrelated to nicotine intake, but this effect may be specific to rewards from stimuli that are "sensory" in nature. We assessed acute effects of nicotine via smoking on responding for music or video rewards (sensory), for monetary reward (nonsensory), or for no reward (control), to gauge the generalizability of nicotine's reinforcement-enhancing effects. Using a fully within-subjects design, dependent smokers (N = 20) participated in 3 similar experimental sessions, each following overnight abstinence (verified by carbon monoxide <10 ppm) and varying only in the smoking condition. Sessions involved no smoking or smoking "denicotinized" ("denic;" 0.05 mg) or nicotine (0.6 mg) Quest brand cigarettes in controlled fashion prior to responding on a simple operant computer task for each reward separately using a progressive ratio schedule. The reinforcing effects of music and video rewards, but not money, were significantly greater due to the nicotine versus denic cigarette (i.e., nicotine per se), whereas there were no differences between denic cigarette smoking and no smoking (i.e., smoking behavior per se), except for no reward. These effects were not influenced by withdrawal relief from either cigarette. Results that generalize from an auditory to a visual reward confirm that acute nicotine intake per se enhances the reinforcing value of sensory rewards, but its effects on the value of other (perhaps nonsensory) types of rewards may be more modest.

Beyond cigarettes per day. A genome-wide association study of the biomarker carbon monoxide

RATIONALE

The CHRNA5-CHRNA3-CHRNB4 locus is associated with self-reported smoking behavior and also harbors the strongest genetic associations with chronic obstructive pulmonary disease (COPD) and lung cancer. Because the associations with lung disease remain after adjustment for self-reported smoking behaviors, it has been asserted that CHRNA5-CHRNA3-CHRNB4 variants increase COPD and lung cancer susceptibility independently of their effects on smoking.

OBJECTIVES

To compare the genetic associations of exhaled carbon monoxide (CO), a biomarker of current cigarette exposure, with self-reported smoking behaviors.

METHODS

A total of 1,521 European American and 247 African American current smokers recruited into smoking cessation studies were assessed for CO at intake before smoking cessation. DNA samples were genotyped using the Illumina Omni2.5 microarray. Genetic associations with CO and smoking behaviors (cigarettes smoked per day, Fagerstrom test for nicotine dependence) were studied.

MEASUREMENTS AND MAIN RESULTS

Variants in the CHRNA5-CHRNA3-CHRNB4 locus, including rs16969968, a nonsynonymous variant in CHRNA5, are genomewide association study-significantly associated with CO (β = 2.66; 95% confidence interval [CI], 1.74-3.58; P = 1.65 × 10(-8)), and this association remains strong after adjusting for smoking behavior (β = 2.18; 95% CI, 1.32-3.04; P = 7.47 × 10(-7)). The correlation between CO and cigarettes per day is statistically significantly lower (z = 3.43; P = 6.07 × 10(-4)) in African Americans (r = 0.14; 95% CI, 0.02-0.26; P = 0.003) than in European-Americans (r = 0.36; 95% CI, 0.31-0.40; P = 0.0001).

CONCLUSIONS

Exhaled CO, a biomarker that is simple to measure, captures aspects of cigarette smoke exposure in current smokers beyond the number of cigarettes smoked per day. Behavioral measures of smoking are therefore insufficient indices of cigarette smoke exposure, suggesting that genetic associations with COPD or lung cancer that persist after adjusting for self-reported smoking behavior may still reflect genetic effects on smoking exposure.

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.

Smoking topography and abstinence in adult female smokers

Preliminary evidence, within both adults and adolescents, suggests that the intensity with which cigarettes are smoked (i.e., smoking topography) is predictive of success during a cessation attempt. These reports have also shown topography to be superior compared to other variables, such as cigarettes per day, in the prediction of abstinence. The possibility that gender may influence this predictive relationship has not been evaluated but may be clinically useful in tailoring gender-specific interventions. Within the context of a clinical trial for smoking cessation among women, adult daily smokers completed a laboratory session that included a 1-hour ad libitum smoking period in which measures of topography were collected (N=135). Participants were then randomized to active medication (nicotine patch vs. varenicline) and abstinence was monitored for 4weeks. Among all smoking topography measures and all abstinence outcomes, a moderate association was found between longer puff duration and greater puff volume and continued smoking during the active 4-week treatment phase, but only within the nicotine patch group. Based on the weak topography-abstinence relationship among female smokers found in the current study, future studies should focus on explicit gender comparisons to examine if these associations are specific to or more robust in male smokers.

A systematic review and analysis of data reduction techniques for the CReSS smoking topography device

Introduction: Characterising smoking behaviour in an objective and ecologically valid manner is integral to understanding health complications associated with tobacco use. Smoking topography (ST) provides a representation of the physical attributes of smoking. However, there is no clear guidance on ST data exclusion and reduction techniques and the impact of different techniques.

Methods: A search was conducted using MEDLINE, PubMed, and Scopus and limited to studies published between 2001‒2012. The search identified 23 studies using the CReSS device.

Results: Few studies reported data reduction (n = 9) and exclusion (n = 4) criteria. Four data reduction techniques emerged and were applied to an existing dataset (n = 193, Mage = 38.98, FTND = 5.19, mean 17.23 cigarettes/day). Using repeated measures ANOVA, there were significant (p < 0.05) differences among all techniques for puff volume, peak flow, puff duration and interpuff interval, which were attenuated upon controlling for puff count.

Conclusions: This review highlights the inconsistency in the literature regarding the disclosure of smoking topography data treatment and provides clear evidence that outcomes vary depending on the technique used. Greater transparency is needed and consideration should be given by researchers to the potential impact of methodological decisions on study findings.

Influence of reinforcer magnitude and nicotine amount on smoking's acute reinforcement enhancing effects

BACKGROUND

Nicotine's acute effects on enhancing reinforcement from sensory rewards, shown in animal models, appear to occur with smoking in humans. These effects may vary due to reinforcer magnitude and amount of acute smoke intake (dose).

METHODS

In a fully within-subjects design, dependent smokers (n=23) participated in 3 sessions. Each session followed overnight abstinence and involved 4 trials to assess responding via progressive ratio (PR 50%) for sensory reinforcement from high, moderate, or low preference music, or no reward (counter-balanced, 30-s/reinforcer). Sessions differed in smoking prior to each trial: 8 puffs on arrival and 2 puffs/trial ("8+2″), 2 puffs/trial only ("0+2″), or no smoking. Puffs were consumed via CReSS (Clinical Research Support System) to control topography, and smoking involved own brand to ensure palatability and increase generalizability of results.

RESULTS

Reinforced responding was influenced by main effects of smoking condition (p<.05) and music reward type (p<.001). Compared to no smoking, responding for music was increased after smoking 8+2/trial puffs (p<.005), but not after 0+2/trial puffs. Smoking condition significantly increased reinforced responding only for the high preference music (p=.01), and not for moderate or low preference music, or for no reward. Withdrawal did not differ between the two smoking sessions, ruling out withdrawal relief as an explanation for differential reinforcement enhancement.

CONCLUSIONS

Our findings confirm that just one cigarette after abstinence is sufficient for reinforcement enhancing effects and suggest that such enhancement is greater as magnitude of a reward's reinforcing efficacy increases.

Variants in two adjacent genes, EGLN2 and CYP2A6, influence smoking behavior related to disease risk via different mechanisms

Genome-wide significant associations with cigarettes per day (CPD) and risk for lung cancer and chronic obstructive pulmonary disease (COPD) were previously reported in a region of 19q13, including CYP2A6 (nicotine metabolism enzyme) and EGLN2 (hypoxia response). The associated single nucleotide polymorphisms (SNPs) were assumed to be proxies for functional variation in CYP2A6. Here, we demonstrate that when CYP2A6 and EGLN2 genotypes are analyzed together, the key EGLN2 variant, rs3733829, is not associated with nicotine metabolism independent of CYP2A6, but is nevertheless independently associated with CPD, and with breath carbon monoxide (CO), a phenotype associated with cigarette consumption and relevant to hypoxia. SNPs in EGLN2 are also associated with nicotine dependence and with smoking efficiency (CO/CPD). These results indicate a previously unappreciated novel mechanism behind genome-wide significant associations with cigarette consumption and disease risk unrelated to nicotine metabolism.

Reinforcement enhancing effects of nicotine via smoking

RATIONALE

In animals, nicotine enhances reinforcement from stimuli unrelated to nicotine intake. Human research is suggestive but has not clearly shown a similar influence of nicotine.

OBJECTIVES

We assessed acute effects of nicotine via smoking on enhancement of positive (money, music) or negative (termination of noise) reinforcers, or no "reward" (control). These different rewards determined the generalizability of nicotine effects.

MATERIALS AND METHODS

Dependent (n = 25) and nondependent (n = 27) smokers participated in three sessions, each after overnight abstinence. Using a within-subjects design, sessions involved no smoking or smoking denicotinized (0.05 mg) or nicotine (0.6 mg) Quest(R) brand cigarettes. For comparison, a fourth session involved no abstinence prior to smoking one's own brand to gauge responses under typical nicotine satiation. Reinforcement was assessed by responses on a simple operant computer task for the rewards, each available singly on a progressive ratio schedule during separate trials.

RESULTS

The reinforcing effect of music, but not other rewards, was greater due to the nicotine cigarette, compared to the denicotinized cigarette or no smoking. Reinforcement enhancing effects of nicotine did not differ between dependent and nondependent groups, indicating no influence of withdrawal relief. Responding due to acute nicotine after abstinence was very similar to responding to one's own brand after no abstinence.

CONCLUSIONS

Acute nicotine intake per se from smoking after abstinence enhances the reinforcing value of rewards unassociated with smoking, perhaps in a manner comparable to ad lib smoking after no abstinence. Nicotine's reinforcement enhancing effects may be specific to certain rewards, perhaps those sensory in nature.