Dose-response effects of spectrum research cigarettes

Effects of reduced nicotine content cigarette advertising with warning labels and social media features on product perceptions among young adults

This study sought to understand reactions to very low nicotine (VLN) cigarette advertising compared with conventional cigarette advertising with consideration of warning labels and social media context. The online experimental study recruited young adult cigarette smokers and nonsmokers (N = 1,608). Participants completed a discrete choice task with a 2 × 2 × 3 mixed design: brand, (VLN, Marlboro), context (Ad only, Ad on social media), and warning (Text-only, Well-known risk pictorial, or Lesser-known risk pictorial). Participants made choices about attention, appeal, harm, buying, and quitting intentions. Social media context increased attention and appeal. A well-known risk pictorial warning outperformed a text-only warning. Smokers had increased odds of quit intentions for VLN ads, yet nonsmokers had increased intentions to buy cigarettes on social media with a text-only warning. Results indicate differences in how young adults react to cigarette ads on social media, especially with the warnings they portray.

Impact of reduced nicotine content on behavioral economic measures of cigarette reinforcement in adolescents who smoke cigarettes

BACKGROUND

Public health officials in the U.S. and New Zealand are considering a reduced nicotine standard for cigarettes to reduce their addictive potential. This study's aim was to evaluate the effects of nicotine reduction on the reinforcing efficacy of cigarettes in adolescents who smoke, which has implications for this policy's potential for success.

METHODS

Adolescents who smoked cigarettes daily (n = 66; mean age: 18.6) participated in a randomized clinical trial assessing effects of assignment to very low nicotine content (VLNC; 0.4 mg/g nicotine) or normal nicotine content (NNC; 15.8 mg/g nicotine) cigarettes. Hypothetical cigarette purchase tasks were completed at baseline and the end of Week 3 and demand curves fit to the data. Linear regressions estimated effects of nicotine content on demand for study cigarettes at baseline and Week 3 and associations between baseline demand for cigarette consumption at Week 3.

RESULTS

An extra sum of squares F-test of fitted demand curves indicated that demand (α) was more elastic among VLNC participants at baseline and Week 3 (F(2, 1016)= 35.72, p < 0.001). Adjusted linear regressions indicated demand was more elastic (ß= 1.45, p < 0.01) and maximum expenditure (Omax) lower (ß= -1.42, p-0.03) among VLNC participants at Week 3. More elastic demand for study cigarettes at baseline predicted lower consumption of cigarettes at Week 3 (p's < 0.01).

CONCLUSIONS

A nicotine reduction policy may reduce the reinforcing value of combustible cigarettes among adolescents. Future work should investigate likely responses to such a policy among youth with other vulnerabilities and evaluate the potential for substitution to other nicotine containing products.

Manipulation of Menthol and Nicotine Content in Cigarettes: Effects on Smoking Behavior and Toxicant Exposure in Women Menthol Smokers

BACKGROUND

The purpose of this study was to determine the effects of smoking and other outcomes of assigning cigarettes with reduced nicotine and/or no menthol to female menthol smokers.

AIMS AND METHODS

Nontreatment-seeking female menthol smokers (N = 263) participated in a randomized controlled trial in which levels of menthol and nicotine in cigarettes were manipulated using experimental cigarettes. After a baseline period, participants were assigned to the following conditions for 6 weeks: (1) their own brand of cigarette (conventional nicotine with menthol), (2) a conventional nicotine cigarette with no menthol, (3) a cigarette with reduced nicotine (RNC) with menthol, or (4) a RNC cigarette and no menthol. Participants then returned to using their own brand and were followed for another 6 weeks. Outcomes included cigarettes smoked, biomarkers of exposure, and dependence measures.

RESULTS

Results indicated that, after an initial increase, rates of smoking of all three experimental cigarettes were at or below baseline rates of smoking of one's own brand. Levels of biomarkers also decreased during the experimental phase but rebounded somewhat after participants resumed smoking their own brand. There was evidence that the overall amount of smoking decreased similarly among women who switched to non-menthol and/or RNC cigarettes.

CONCLUSIONS

These results suggest that no detrimental effect will occur in nicotine or toxicant exposure levels with a ban on characterizing menthol and/or a product standard on nicotine content in cigarettes.

IMPLICATIONS

The implication of this work is that there would be no risk to women menthol smokers associated with regulations restricting nicotine and eliminating menthol in cigarettes.

Predictors of Adherence Among Vulnerable Populations of Adults Assigned to Smoke Very Low Nicotine Content Cigarettes

INTRODUCTION

Regulators are considering reducing the nicotine content in cigarettes to a minimally addictive level. This could particularly benefit smokers from populations vulnerable to heavy smoking and difficulties quitting. We assessed predictors of adherence among adults from vulnerable populations assigned to use very low nicotine content cigarettes (VLNCs) in randomized clinical trials, to identify characteristics of those who require additional assistance if a nicotine reduction policy were implemented.

AIMS AND METHODS

Data came from three populations of vulnerable adult smokers assigned to use VLNC cigarettes (0.4 mg/g nicotine) during 12-week randomized controlled trials (n = 286): Socioeconomically disadvantaged women of reproductive age, opioid-maintained adults, and adults with affective disorders. Logistic and linear regressions modeled predictors of adherence based on changes in cotinine at week-6 and week-12 assessments relative to baseline, and as a 90% reduction in cotinine relative to baseline (full adherence: yes/no). Predictors included satisfaction with study cigarettes, craving, nicotine dependence severity, withdrawal, population membership, baseline affective-disorder symptoms, and sociodemographic characteristics.

RESULTS

Dependence severity was negatively associated with both adherence measures at week 6 (p < .01), whereas increased satisfaction with study cigarettes and age were positively associated with both measures at weeks 6 and 12 (p < .01). Opioid-maintained adults exhibited reduced adherence and were less likely to reach full adherence at week 12 compared to disadvantaged women (p = .02).

CONCLUSIONS

Factors associated with VLNC adherence in vulnerable populations are similar to those in the general population of smokers. Furthermore, studies are indicated investigating nicotine supplements (e.g., e-cigarettes, NRT) to support highly dependent adults faced with using VLNCs.

IMPLICATIONS

This study identified factors predicting difficulty maintaining adherence to a regimen of very low nicotine content cigarettes (VLNC) among adults from vulnerable populations. Findings suggested that factors predicting difficulty maintaining adherence (greater nicotine dependence and low satisfaction with study-provided VLNC) were common across vulnerable smokers and the general population of adults who smoke. Furthermore, research should investigate alternatives to support highly dependent adults, such as pairing VLNC with supplemental, noncombusted nicotine. Some vulnerable populations (e.g., opioid-maintained adults) may be especially in need of supplemental, noncombusted nicotine.

Acute nicotine reinforcement requires ability to discriminate the stimulus effects of nicotine

This review of research on behavioral discrimination of nicotine and how it informs public health policy for reducing risk of tobacco dependence is adapted from Kenneth A. Perkins's American Psychological Association Division 28 (Psychopharmacology and Substance Abuse) 2020 Med Associates Brady/Schuster Award Lecture. The author's initial programmatic clinical research on nicotine is introduced, especially efforts to develop and validate a novel method of acute nicotine dosing. After the public health rationale for characterizing the discriminative stimulus effects of nicotine in humans are described, details from two separate programs of research on nicotine discrimination in humans are presented. The first, conducted with nicotine dosing by nasal spray, documented that humans could discriminate nicotine administered rapidly, examined nicotine's neuropharmacological specificity, identified discrimination threshold dose in smokers and nonsmokers, and explored other conditions that might alter ability to discriminate its effects. The second, more recent program focused on threshold doses for discrimination of nicotine by cigarette smoking, a program that was very difficult to do until the past decade, and how nicotine's self-reported "reward" and preference via choice behavior relate to its discriminability. Differences due to menthol and degree of tobacco dependence were also examined. For each of these two programs, the main findings of selected studies are noted, followed by very recent work on nicotine discrimination and choice that informs Food and Drug Administration's efforts to formulate public policy to improve health and reduce the nearly half million American deaths per year due to persistent tobacco use. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Reactions to reduced nicotine content cigarettes in a sample of young adult, low-frequency smokers

RATIONALE

Reducing nicotine content in cigarettes to ≤ 2.4 mg per g of tobacco [mg/g] reduces smoking behavior and toxicant exposure among adult daily smokers. However, cigarettes with similar nicotine content could support continued experimentation and smoking progression among young adults who smoke infrequently.

OBJECTIVES

This study evaluated the threshold for nicotine in cigarettes that produces reactions associated with smoking progression in a sample of young adults who smoke infrequently.

METHODS

Young adults (n = 87, 18-25 years, 49% female) using tobacco products ≤ 15 days per month completed three counterbalanced, double-blinded sessions, each measuring positive and negative subjective reactions to fixed doses of smoke from investigational cigarettes containing one of three different nicotine contents: normal (NNC; 15.8 mg/g); very low (VLNC; 0.4 mg/g); and intermediate (INC; 2.4 mg/g). In a final session, participants chose one of the cigarettes to self-administer.

RESULTS

Post-cigarette breath carbon monoxide was greater for VLNC than for NNC (p < 0.001). Positive reactions were greater for NNC than INC (p < 0.001) and for INC than VLNC (p = 0.001). Negative reactions were greater for NNC than INC and VLNC (both p < 0.001); INC and VLNC did not differ. Cigarette choices did not differ from an even distribution (43% NNC, 25% INC, 32% VLNC), but choice for NNC or INC was associated with higher ratio of positive to negative reactions during the NNC and INC fixed dose sessions, respectively (p < 0.001).

CONCLUSIONS

Reducing nicotine content will likely lower the abuse liability of cigarettes for most young, low-frequency smokers. Additional work is needed to determine if compensatory smoking may lead to increased toxicant exposure, and if a subset of individuals choosing lower nicotine cigarettes may continue to smoke regardless of nicotine content.

Regulatory approaches and implementation of minimally addictive combusted products

INTRODUCTION

A joint meeting was held by the World Health Organization (WHO) and the Convention Secretariat of the WHO Framework Convention on Tobacco Control to examine the potential effects of a regulatory policy to reduce nicotine in cigarettes to minimally addictive levels. This paper reviews the feasibility of and approaches to implementing a nicotine product standard.

METHODS

Prior WHO reports on this topic were consulted and a systematic review of the scientific literature was conducted. The paper was reviewed by the participants at the aforementioned meeting and their feedback was incorporated.

RESULTS

The nicotine dose most likely to consistently reduce smoking behavior and dependence is < 0.4 mg nicotine/g tobacco. An immediate rather than a gradual nicotine reduction approach appears to be more beneficial. Smokers are likely to seek nicotine from alternate sources (e.g., nicotine replacement therapies, e-cigarettes) or potentially, the illegal market. As such, the availability of alternative products, as well as strong policies against illegal markets, can potentially mitigate unintended consequences. An effective reduced nicotine regulation must be imbedded in a comprehensive and strong tobacco control program that includes public education and surveillance. Barriers and challenges to implementing a nicotine product standard exist, particularly in low-capacity countries.

CONCLUSION

Not all countries will have the capacity to implement a regulation to reduce nicotine in cigarettes (and preferably other combusted tobacco products) to minimally addictive levels. However, for the countries that choose to implement it, such a policy could potentially dramatically reduce the burden of tobacco use.

Acute subjective sensory perceptions predict relative reinforcing effects of smoked nicotine

INTRODUCTION

Smoking is believed partially reinforcing via immediate sensory perceptions. Yet, unknown is whether a cigarette's relative reinforcing efficacy can be predicted by these perceptions and whether this relationship may vary due to constituents known to alter those perceptions.

METHODS

Sensory perceptions of acute smoking were examined as predictors of subsequent cigarette choice behavior. Also tested was whether nicotine content or menthol affected this relationship. Adult dependent smokers (N = 37) participated in five sessions comparing cigarettes varying in nicotine contents (NIC; 1.3, 2.3, 5.5, 11.2, and 17.4 mg/g), relative to the very lowest nicotine content, 0.4 mg/g (VLNC). Non-menthol (n = 17) and menthol (n = 20) cigarettes-matched on nicotine-were provided based on participant preference. One NIC was compared versus VLNC per session (single-blinded); NIC content order was randomized across sessions on separate days. Perceptions (e.g., "liking", "satisfying") were measured immediately after initial sampling of NIC or VLNC, followed by a validated puff-by-puff choice procedure to determine preference for each NIC versus VLNC.

RESULTS

NIC perceptions (difference from VLNC) and puff choices increased with nicotine. Menthol moderated associations between perceptions and nicotine; and between puff choices and nicotine. Perceptions were predictive of puff choice-greater magnitude of difference in perceptions between VLNC and NIC led to more NIC puff choices. When testing perceptions' prediction of puff choices, neither the main effect of menthol or interaction of Perceptions X Nicotine Condition were significant.

CONCLUSIONS

Consistent with assumed-but rarely tested-causes of smoking reinforcement, sensory perceptions from a cigarette predict its relative reinforcing efficacy.

Tobacco smoke exposure enhances reward sensitivity in male and female rats

RATIONALE

Systemic administration of the tobacco smoke constituent nicotine stimulates brain reward function in rats. However, it is unknown if the inhalation of tobacco smoke affects brain reward function.

OBJECTIVES

These experiments investigated if exposure to smoke from high-nicotine SPECTRUM research cigarettes increases reward function and affects the rewarding effects of nicotine in adult male and female Wistar rats.

METHODS

Reward function after smoke or nicotine exposure was investigated using the intracranial self-stimulation (ICSS) procedure. A decrease in reward thresholds reflects an increase in reward function. In the first experiment, the rats were exposed to tobacco smoke for 40 min/day for 9 days, and the rewarding effects of nicotine (0.03-0.6 mg/kg) were investigated 3 weeks later. In the second experiment, the dose effects of tobacco smoke exposure (40-min sessions, 1-4 cigarettes burnt simultaneously) on reward function were investigated.

RESULTS

Tobacco smoke exposure did not affect the nicotine-induced decrease in reward thresholds or response latencies in male and female rats. Smoke exposure lowered the brain reward thresholds to a similar degree in males and females and caused a greater decrease in latencies in females. There was a positive relationship between plasma nicotine and cotinine levels and the nicotine content of the SPECTRUM research cigarettes. Similar smoke exposure conditions led to higher plasma nicotine and cotinine levels in female than male rats.

CONCLUSION

These findings indicate that tobacco smoke exposure enhances brain reward function but does not potentiate the rewarding effects of nicotine in male and female rats.

An Evaluation of Potential Unintended Consequences of a Nicotine Product Standard: A Focus on Drinking History and Outcomes

INTRODUCTION

A nicotine product standard reducing the nicotine content in cigarettes could improve public health by reducing smoking. This study evaluated the potential unintended consequences of a reduced nicotine product standard by examining its effects on (1) smoking behaviors based on drinking history; (2) drinking behavior; and (3) daily associations between smoking and drinking.

METHODS

Adults who smoke daily (n = 752) in the United States were randomly assigned to smoke very low nicotine content (VLNC) cigarettes versus normal nicotine content (NNC; control) cigarettes for 20 weeks. Linear mixed models determined if baseline drinking moderated the effects of VLNC versus NNC cigarettes on Week 20 smoking outcomes. Time-varying effect models estimated the daily association between smoking VLNC cigarettes and drinking outcomes.

RESULTS

Higher baseline alcohol use (vs no use or lower use) was associated with a smaller effect of VLNC on Week 20 urinary total nicotine equivalents (ps < .05). No additional moderation was supported (ps > .05). In the subsample who drank (n = 415), in the VLNC versus NNC condition, daily alcohol use was significantly reduced from Weeks 17 to 20 and odds of binge drinking were significantly reduced from Weeks 9 to 17. By Week 7, in the VLNC cigarette condition (n = 272), smoking no longer predicted alcohol use but remained associated with binge drinking.

CONCLUSIONS

We did not support negative unintended consequences of a nicotine product standard. Nicotine reduction in cigarettes generally affected smoking behavior for individuals who do not drink or drink light-to-moderate amounts in similar ways. Extended VLNC cigarette use may improve public health by reducing drinking behavior.

IMPLICATIONS

There was no evidence that a VLNC product standard would result in unintended consequences based on drinking history or when considering alcohol outcomes. Specifically, we found that a very low nicotine standard in cigarettes generally reduces smoking outcomes for those who do not drink and those who drink light-to-moderate amounts. Furthermore, an added public health benefit of a very low nicotine standard for cigarettes could be a reduction in alcohol use and binge drinking over time. Finally, smoking VLNC cigarettes may result in a decoupling of the daily associations between smoking and drinking.

Pharmacokinetic Profile of Spectrum Reduced Nicotine Cigarettes

INTRODUCTION

Spectrum research cigarettes have been developed with varying nicotine content for use in studies evaluating the effects of a regulatory policy reducing the permissible nicotine content in cigarettes. This study aimed to characterize the nicotine pharmacokinetic profile of Spectrum cigarettes.

METHODS

Twelve daily smokers attended four sessions and had blood nicotine, exhaled carbon monoxide, and subjective effects measured before and after smoking either a single cigarette of their preferred brand or high (10.9 mg/cigarette), medium (3.2 mg/cigarette), or low (0.2 mg/cigarette) nicotine content Spectrum research cigarettes, in a double-blind design with order counterbalanced.

RESULTS

The boost in blood nicotine concentration was dose-dependent, with a boost of 0.3, 3.9, and 17.3 ng/mL for low-, medium-, and high-nicotine content Spectrum cigarettes. The high dose Spectrum had a similar nicotine boost to the "preferred brand" cigarettes (19 ng/mL). Subjects took longer puffs on the low nicotine cigarettes, but smoked these cigarettes faster than other cigarette types. High nicotine Spectrum cigarettes reduced the urge to smoke more than other cigarette types.

CONCLUSIONS

This study shows that Spectrum research cigarettes produce blood nicotine absorption in a dose-dependent manner, and therefore, are appropriate for use in studies of nicotine reduction in cigarettes.

IMPLICATIONS

This is the first study to determine the pharmacokinetic profile of Spectrum reduced nicotine content research cigarettes following an overnight abstinence. These data could provide evidence to regulatory agencies about the effects of reduced nicotine cigarettes when considering regulations on tobacco reduction.

Adolescent nicotine and tobacco smoke exposure enhances nicotine self-administration in female rats

Most people start experimenting with tobacco products or e-cigarettes in early adolescence and become habitual smokers in late adolescence or adulthood. These studies investigated if exposure to tobacco smoke or nicotine during early and mid-adolescence affects nicotine intake in late adolescence and early adulthood. Male and female rats were exposed to tobacco smoke from low- and high-nicotine SPECTRUM cigarettes or nicotine (0.3 mg/kg, twice a day) from postnatal day (P) 24-42. The self-administration sessions started at P55. The rats self-administered nicotine for 14-15 days under a fixed-ratio 1 schedule, and on the first day, the maximum number of infusions was twenty. Exposure to smoke from high, but not low, nicotine cigarettes during adolescence increased nicotine self-administration in female but not male rats. Adolescent treatment with nicotine facilitated nicotine self-administration. On the first day of nicotine self-administration, nicotine-treated rats reached the maximum number of infusions before the saline-treated control rats. Nicotine intake was also higher in the nicotine-treated female rats than in the saline-treated females. There was no sex difference in nicotine intake in controls when the data from the studies were combined. Smoke exposure led to a dose-dependent increase in plasma nicotine and cotinine levels in adolescent rats. Exposure to smoke from high-nicotine cigarettes and 0.3 mg/kg of nicotine led to plasma nicotine and cotinine levels that are similar to those in tobacco users. These findings indicate that in females, but not males, exposure to nicotine during adolescence may facilitate smoking and e-cigarette use later in life.

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.

Nicotine Reduction in Cigarettes: Literature Review and Gap Analysis

BACKGROUND

The US Food and Drug Administration (FDA) is considering reducing nicotine levels in cigarettes to "minimally or non-addictive levels." However, important research gaps remain, and the FDA must determine when the available research is sufficient to support moving forward.

METHODS

The authors conducted a systematic review of research articles in PubMed relating to nicotine reduction. Building on a review of risk assessment best practices, the authors also developed a risk assessment framework for tobacco regulation and used it to guide a gap analysis of nicotine reduction research.

RESULTS

The final sample consisted of 78 articles. The majority examined either nicotine dependence on very low nicotine cigarettes (VLNCs) or markers of potential health effects of using VLNCs. One-third of the identified articles reported results from four large randomized controlled trials (RCTs). While these studies report promising results and suggest that a nicotine reduction rule would be a powerful tool to reduce cigarette smoking, our gap analysis suggests that there is a need for studies that better reflect the use and availability of a wide range of tobacco/nicotine products and the potential for dual- or multi-product use.

CONCLUSION

The current body of research on nicotine reduction is weighted towards RCTs, which is appropriate for a policy that has not yet been implemented anywhere in the world. The FDA must consider a wide range of factors that may impact a product standard's public health impact, including those difficult to assess in RCTs, such as a nicotine reduction rule's impact on smoking initiation and relapse.

IMPLICATIONS

This systematic review presents a gap analysis based on a risk assessment framework to help identify remaining research priorities to inform FDA's potential product standard to reduce nicotine levels in cigarettes. Quickly addressing those gaps would support the FDA's effort to develop a nicotine reduction product standard that will be effective and withstand legal challenges.

Examining Age as a Potential Moderator of Response to Reduced Nicotine Content Cigarettes in Vulnerable Populations

Introduction

Young adults (aged 18–24 years) have a higher smoking prevalence than younger and older age groups and young adulthood is an important developmental period during which long-term behavior patterns like cigarette smoking are established. The aim of the current study was to examine how young adult smokers with additional vulnerabilities to smoking respond to reduced nicotine content cigarettes.

Methods

This is a secondary analysis of a double-blind, within-subject experiment conducted with 169 cigarette smokers recruited from populations with comorbid psychiatric conditions or socioeconomic disadvantage assessing acute effects of research cigarettes varying in nicotine content (0.4, 2.4, 5.2, 15.8 mg/g). Participants were dichotomized by chronological age (18–24 vs. ≥25 years). Across 14 laboratory sessions effects of nicotine content were examined on measures of relative reinforcing efficacy (Cigarette Purchase Task [CPT] and Concurrent Choice testing), subjective effects, craving/withdrawal, and smoking topography. Repeated measures analysis of variances were used to examine potential moderating effects of age.

Results

Young adults exhibited lower demand for reduced nicotine content cigarettes than older adults across three of five CPT indices (ps < .05). No differences by age were observed on other measures of reinforcing efficacy, subjective effects, craving/withdrawal, or smoking topography where effects generally decreased as an orderly function of decreasing nicotine content (ps <.05).

Conclusion

Overall, these findings suggest that reducing the nicotine content of cigarettes would decrease the addiction potential of cigarette smoking in young adult smokers as much or perhaps more than older adult smokers from populations at increased vulnerability to smoking, addiction, and smoking-related health consequences.

Implications

Reducing the nicotine content in cigarettes to lower addiction potential of smoking has been proposed as a means to improve overall population health. It is imperative to examine how young adults may respond to a nicotine reduction policy. We saw minimal evidence that age moderates acute response and where there was evidence it was in the direction of reduced nicotine content cigarettes having less addictive potential among young versus older adults (eg, steeper decreases in demand for very low nicotine content cigarettes among young versus older adults). Overall, a nicotine reduction policy has the potential to reduce smoking across age groups.

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.

Examining Risk Perceptions Among Daily Smokers Naïve to Reduced Nicotine Content Cigarettes

INTRODUCTION

The U.S. Food and Drug Administration (FDA) has stated its interest in reducing the addictiveness of combustible cigarettes by lowering their nicotine content. Delineating risk perceptions of reduced nicotine content (RNC) cigarettes prior to federal regulation may inform the content of future educational campaigns accompanying this policy.

METHODS

Five hundred non-treatment-seeking, daily smokers naïve to RNC cigarettes (63.0% male, 51.6% nonWhite, mean [SD] cigarettes per day = 15.69 [7.58], age = 43.44 [11.46]) completed a 10-item RNC cigarette risk perception questionnaire at baseline in two, unrelated experimental studies. We used multinomial logistic regression models to identify demographic (eg, gender) and smoking-related (eg, nicotine dependence) correlates of RNC cigarette risk perceptions.

RESULTS

Although the majority of participants did not misperceive RNC cigarettes as less harmful than regular or high nicotine cigarettes, a large portion of the sample held misperceptions about RNC cigarettes' addictiveness (56.4%) and cessation aid potential (63.4%). More than 20% of the sample reported being unsure about RNC-related risks, especially tar content (51.8%). NonWhite smokers were 2.5 to 3 times more likely to be incorrect about multiple RNC cigarette risks (p = .002-.006).

CONCLUSIONS

If the FDA mandates a reduced nicotine content standard for cigarettes, educational campaigns will be needed to correct misperceptions about RNC cigarettes' addictiveness and potential to aid cessation as well as inform consumers about their safety risks. Campaigns tailored toward nonWhite smokers may also be needed to correct misperceptions of RNC cigarette risks held by this subgroup.

IMPLICATIONS

The FDA has stated its interest in reducing cigarettes' addictiveness by lowering their nicotine content, enabling smokers to quit. Our findings suggest that most smokers who have not used RNC cigarettes do not perceive these products as less addictive or as cessation tools, stressing a need for future educational campaigns to correct these misperceptions. Campaigns are also needed to educate uninformed smokers about RNC cigarettes and should consider targeting messages toward subgroups likely to hold misperceptions about the risks and benefits of using these products (eg, nonWhite smokers).

The Impact of Exclusive Use of Very Low Nicotine Cigarettes on Compensatory Smoking: An Inpatient Crossover Clinical Trial

BACKGROUND

The FDA is considering a mandated reduction in the nicotine content of cigarettes. Clinical trials have been limited by non-study cigarette use (noncompliance), which could mask compensation. The goal of this study was to assess whether compensation occurs when smokers provided with very low nicotine cigarettes cannot access normal nicotine cigarettes.

METHODS

In a within-subjects, crossover design, current smokers (n = 16) were confined to a hotel for two 4-night hotel stays during which they were only able to access the research cigarettes provided. The hotel stays offered normal nicotine cigarettes or very low nicotine content (VLNC) cigarettes, in an unblinded design, available for "purchase" via a study bank.

RESULTS

In the context of complete compliance with the study cigarettes (n = 16), there was not a significant increase during the VLNC condition for cigarettes smoked per day, expired carbon monoxide, or N-acetyl-S-(cyanoethyl)-l-cysteine (cyanoethyl-MA, metabolite of acrylonitrile). There was a significant nicotine × time interaction on urine N-acetyl-S-(3-hydroxypropyl)-l-cysteine (hydroxypropyl-MA, metabolite of acrolein), driven by an increase in the VLNC condition during the first 24 hours. By the end of the VLNC condition, there was no evidence of compensation across any measure of smoking or smoke exposure.

CONCLUSIONS

Among current smokers who exclusively used VLNC cigarettes for 4 days, there was no significant compensatory smoking behavior.

IMPACT

These data, combined with the larger body of work, suggest that a mandated reduction in nicotine content is unlikely to result in an increase in smoking behavior to obtain more nicotine.

Preclinical and clinical research on the discriminative stimulus effects of nicotine

Across species, nicotine can produce robust discriminative stimulus (DS) effects, as with other drugs of abuse, a feature that has been harnessed to advance our understanding on the neuropharmacological mechanisms of nicotine's actions. With the crucial role played by nicotine in supporting tobacco dependence, nicotine DS effects have presented an ideal platform to develop novel generation of smoking cessation compounds. Findings from preclinical strands of research have invigorated the field of human discrimination research to objectively assess nicotine's interoceptive stimulus effects. As such, translation studies provide proof of concept for nicotine DS research as a method to assess the subjective effects of nicotine per se, separate from non-nicotine stimuli involved in smoking. Recent clinical studies with low doses have demonstrated that perceiving nicotine's DS effects is necessary, yet not sufficient, for that dose to be reinforcing. These measures have been instrumental in developing novel strategies with regards to establishing threshold doses of nicotine contained in tobacco products, to then determine subthreshold doses that cannot be discriminated and, therefore, fail to maintain reinforcement. Findings from preclinical and clinical nicotine DS research could substantially inform public health policies aimed at regulating nicotine content of consumer products so that they minimize risks of dependency. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.

Effects of Cigarette Nicotine Content and Menthol Preference on Perceived Health Risks, Subjective Ratings, and Carbon Monoxide Exposure Among Adolescent Smokers

INTRODUCTION

Minimal research exists on adolescent smokers' perceptions of very low-nicotine-content (VLNC) cigarettes. As approximately half of adolescent smokers prefer menthol cigarettes, it is important to consider the influence of menthol preference on VLNC cigarette perceptions and to what extent menthol preference may affect VLNC smoking behavior. This study examined the effects of cigarette nicotine content and menthol preference or menthol smoking on health risk perceptions, subjective ratings, and carbon monoxide (CO) boost in adolescent smokers.

METHODS

Across two counterbalanced sessions, adolescent smokers sampled VLNC and normal nicotine content (NNC) research cigarettes following overnight abstinence. Cigarettes were mentholated or non-mentholated consistent with participants' usual brand. In each session, participants smoked the research cigarette and then completed the Perceived Health Risk Scale and Cigarette Evaluation Scale. Breath CO readings were obtained pre- and post-smoking. Mixed-factor ANOVA tests compared outcomes with cigarette type (VLNC vs. NNC) as the within-subjects factor and menthol preference as the between-subjects factor.

RESULTS

Participants (N = 50) were M = 17.7 years old, smoked M = 8.2 cigarettes/day, and 56% typically smoked menthol cigarettes. Participants reported lower risk of developing lung cancer, other cancers, emphysema, bronchitis, and heart disease (ps ≤ .05) when smoking VLNC cigarettes relative to NNC cigarettes. Perceived risk of addiction and stroke did not differ by nicotine content. Menthol preference or menthol smoking did not moderate risk perceptions, subjective ratings, or CO boost.

CONCLUSIONS

Adolescents may incorrectly perceive that VLNC cigarettes are less harmful products. Health communication campaigns could help to correct VLNC misperceptions and potentially minimize unintended consequences of a nicotine reduction policy.

The Impact of Gradual and Immediate Nicotine Reduction on Subjective Cigarette Ratings

BACKGROUND

A recent clinical trial showed that an immediate transition to very low nicotine content (VLNC) cigarettes, compared with a gradual transition, produced greater reductions in smoking behavior, smoke exposure, and dependence. However, there was less compliance with the instruction to smoke only VLNC cigarettes in the immediate versus gradual reduction condition. The goal of this study was to test whether nicotine reduction method alters subjective ratings of VLNC cigarettes, and whether subjective ratings mediate effects of nicotine reduction method on smoking behavior, smoke exposure, dependence, and compliance.

METHODS

This is a secondary analysis of a randomized trial conducted across 10 sites in the United States. Smokers (n = 1250) were randomized to either a control condition, or to have the nicotine content of their cigarettes reduced immediately or gradually to 0.04 mg nicotine/g of tobacco during a 20-week study period. Participants completed the modified Cigarette Evaluation Questionnaire (mCEQ).

RESULTS

After Week 20, the immediate reduction group scored significantly lower than the gradual reduction group on multiple subscales of the mCEQ (ps < .001). The Satisfaction subscale of the mCEQ mediated the impact of nicotine reduction method on smoke exposure, smoking behavior, dependence, compliance, and abstinence. Other subscales also mediated a subset of these outcomes.

CONCLUSIONS

An immediate reduction in nicotine content resulted in lower product satisfaction than a gradual reduction, suggesting that immediate reduction further reduces cigarette reward value. This study will provide the Food and Drug Administration with information about the impact of nicotine reduction method on cigarette reward value.

IMPLICATIONS

These data suggest that an immediate reduction in nicotine content will result in greater reductions in cigarette satisfaction than a gradual reduction, and this reduction in satisfaction is related to changes in smoking behavior and dependence.

Smokers' behavioral intentions in response to a low-nicotine cigarette policy

INTRODUCTION

Evidence suggests that reducing the nicotine concentration in cigarettes to sub-addictive levels would reduce use. Until a low-nicotine cigarette policy is enacted, population-level effects are unknown. This study examines the behavioral intentions of current U.S. cigarette smokers if a low-nicotine policy were implemented.

METHODS

Data were drawn from a nationally representative probability-based panel and opt-in panel. Weighted logistic regressions examined likelihood to (1) smoke lower nicotine cigarettes, (2) quit using tobacco, (3) use e-cigarettes, (4) illegally buy high-nicotine cigarettes, and (5) smoke cigars, cigarillos, or little cigars (CLCCs) among smokers, controlling for demographics, tobacco products used, dependence, and intentions to quit cigarettes. Latent class analyses (LCA) characterized patterns of behavioral intentions.

RESULTS

If a low-nicotine policy were implemented, most participants indicated a likelihood to smoke low-nicotine cigarettes (78.4%) or quit tobacco (61.9%), followed by use e-cigarettes (46.5%). Individuals with greater dependence had greater odds of intending to smoke low-nicotine cigarettes, use e-cigarettes, and illegally buy high-nicotine cigarettes. Current e-cigarette or CLCCs users had higher odds of intending to use these products. LCA revealed that individuals would 1) use low-nicotine cigarettes with low intentions to use other tobacco products or 2) use multiple tobacco products, including low-nicotine cigarettes.

CONCLUSIONS

A reduced nicotine standard for all combustible tobacco products is needed given that many tobacco users would likely intend to continue to use tobacco products. Differences in intentions by tobacco use and demographic characteristics indicate a need for additional cessation support and education around the harms of continued use of combustible tobacco.

Examining effects of unit price on preference for reduced nicotine content cigarettes and smoking rate

Cigarette preference increases as a function of greater nicotine content, but manipulating cost can shift preference. The aims of the present study are to model whether (1) the behavioral-economic metric unit price (cost/reinforcer magnitude) accounts for preference shifts and (2) whether preference shifts toward reduced nicotine content are associated with smoking reductions. In a multisite study between 2015 and 2016, 169 daily smokers from vulnerable populations completed two concurrent-choice conditions examining preference for smoking normal (15.8 mg/g) and reduced (0.4 mg/g) nicotine content cigarettes. In Condition 1, both products were available at 10 responses/choice. In Condition 2, availability of the 0.4 mg/g dose remained at 10 responses/choice while the 15.8 mg/g dose was available on a progressive-ratio (PR) schedule wherein response cost increased following each choice. Unit prices were calculated by dividing dose by response requirement. Results were analyzed using ANOVA and binomial tests (p < .05). Participants preferred the 15.8 over 0.4 mg/g dose in Condition 1, but shifted preference to the 0.4 mg/g dose in Condition 2 (p < .001) immediately before the point in the PR progression where unit price for 15.8 dose exceeded unit price for the 0.4 dose (p < .001). This shift was associated with a reduction in smoking (p < .001). The unit price of nicotine appears to underpin cigarette product preference and may provide a metric for predicting preference and potentially impacting it through tobacco regulations. These results also demonstrate that reduced compared to normal nicotine content cigarettes sustain lower smoking rates discernible even under acute laboratory conditions and in vulnerable populations.

Discrimination of nicotine content in electronic cigarettes

INTRODUCTION

Behavioral discrimination of nicotine has only recently been assessed in humans, administered mostly by nasal spray before the newly available Spectrum research cigarettes differing in nicotine content. Here we wanted to explore applicability of these procedures to assess discrimination of nicotine administered by e-cigarettes.

METHODS

In this feasibility study, 16 adult smokers were tested on ability to discriminate e-cigarettes with nicotine concentrations of 36, 24, and 12 mg/ml, one per session (in that order), from a placebo (0 mg/ml), each identified only by letter code. Reliable discrimination was defined by accurately identifying which was which (i.e. nicotine vs placebo) on >85% of trials (i.e. ≥7 of 8; p < .05). Subjective perceptions were also assessed.

RESULTS

Discrimination from placebo was shown with 36 mg/ml and with 24 mg/ml nicotine in 15 of 16 subjects, but only 10 discriminated placebo from 12 mg/ml nicotine. Subjective items previously related to acute nicotine exposure ("how much nicotine", "head rush/buzzed" on 0-100 VAS) generally showed nicotine concentration-dependent effects, as expected, but so did "throat irritation".

CONCLUSIONS

Preliminary results confirm feasibility of using our behavioral procedure to assess ability to discriminate nicotine administered via these e-cigarettes, broadening generalizability of this procedure beyond nicotine via nasal spray and smoked tobacco cigarettes. Findings also suggest its applicability with testing discrimination of nicotine via other methods of rapid dosing (e.g., hookah, novel products), including the newer e-cigarette products. Further study with larger samples may identify individual difference and other factors influencing nicotine discrimination administered via e-cigarettes and other products.

Evaluating the utility of the modified cigarette evaluation questionnaire and cigarette purchase task for predicting acute relative reinforcing efficacy of cigarettes varying in nicotine content

BACKGROUND

Nicotine is the addictive component in cigarettes that maintain cigarette smoking that subsequently leads to morbidity and mortality. Methods for assessing the abuse liability of cigarettes are essential to inform new tobacco product standards. This secondary analysis evaluated the utility of one subjective effects measure, the modified Cigarette Evaluation Questionnaire (mCEQ), and one behavioral economic task, the Cigarette Purchase Task (CPT), for predicting acute relative reinforcing efficacy measured by concurrent choice Self-Administration (SA).

METHODS

Smokers (N = 169) belonging to one of three vulnerable populations participated in a multi-site, double-blind study evaluating research cigarettes with varying levels of nicotine (0.4, 2.4, 5.2, 15.8 mg/g). Participants sampled cigarettes and completed the mCEQ and CPT. In subsequent sessions, cigarette preference was assessed using a concurrent choice SA procedure. Mixed-model repeated measures analysis of variance tests were used to evaluate the utility of the mCEQ subscales and CPT indices for predicting preference for the higher compared to lower nicotine content cigarettes. In addition, stepwise regressions were used to determine which subscales and indices independently predicted concurrent choice SA.

RESULTS

Greater increases on the Satisfaction and Enjoyment of Respiratory Tract Sensations mCEQ subscales independently predicted higher dose preference in concurrent choice testing. Elasticity was the only CPT index that predicted choice. However, its predictive utility differed by dose among opioid-maintained individuals.

CONCLUSION

The mCEQ and CPT predict behavioral measures of relative reinforcing efficacy as assessed in concurrent choice SA, with the mCEQ Satisfaction and Enjoyment of Respiratory Tract Sensations subscales being the strongest independent predictors.

The Impact of Nicotine Dose on the Reinforcing Value of Cigarettes in Adolescents

Objectives

The FDA is considering the implementation of a national nicotine reduction policy for cigarettes, and such a policy may reduce the reinforcing efficacy of cigarettes and ultimately reduce tobacco dependence. However, it is not yet known how different levels of nicotine may affect the reinforcing efficacy of cigarettes in adolescents. We aimed to determine how reduced nicotine content may affect adolescents' demand for cigarettes using the cigarette purchase task (CPT).

Methods

Adolescent daily smokers (ages 15-19, n = 50) completed a CPT for their usual brand cigarette and for each dose of SPECTRUM research cigarettes (15.8, 5.2, 1.3, 0.4 mg nicotine/g tobacco) during four laboratory sessions. We conducted repeated measures ANOVAs to evaluate the effect of nicotine dose on five demand indices derived from the CPT.

Results

Tests revealed significantly higher demand for usual brand than each research cigarette dose (all p's < .01); dose did not significantly affect any measure when usual brand was excluded.

Conclusions

These results demonstrate the potential utility of the CPT for comparing the reinforcing efficacy of cigarettes varying in nicotine content in adolescents, and indicate a significantly reduced reinforcing efficacy of all research cigarettes relative to usual brand.

Response to Reduced Nicotine Content in Vulnerable Populations: Effect of Menthol Status

Objectives

In this study, we investigated potential effects of being a menthol smoker on response to reduced nicotine content (RNC) cigarettes in smokers especially vulnerable to smoking.

Method

Participants were 169 smokers (61 menthol and 108 non-menthol smokers) with comorbid mental illness, substance use disorder, or socioeconomic disadvantage. Participants completed a double-blind study assessing addiction potential, withdrawal/craving, and compensatory smoking across 4 research cigarettes varying in nicotine content from very low levels to commercial levels (0.4, 2.4, 5.2, 15.8mg/g of tobacco). Repeated measures analysis of variance was used to examine potential moderating effects of menthol status.

Results

Statistically significant effects of nicotine dose were noted across measures, with higher doses producing greater economic demand and relief from withdrawal/craving. The relationships between nicotine dose and response to RNC cigarettes do not differ by menthol status.

Conclusions

Results of this study suggest menthol does not have a differential impact on response to RNC cigarettes across measures of economic demand, withdrawal/craving, or smoking topography. These results suggest that any potential beneficial effects of RNC cigarettes should extend to menthol smokers including those especially vulnerable to smoking.

Whether to push or pull? Nicotine reduction and non-combusted alternatives - Two strategies for reducing smoking and improving public health

Combustible cigarettes remain the most harmful and addictive tobacco product, and reducing the prevalence of smoking continues to be a critical public health goal. While nicotine is the constituent primarily responsible for addiction to cigarettes, most of the harm associated with smoking comes from byproducts of tobacco combustion. Recently, two different approaches for reducing the harms of smoking have emerged, both of which focus on breaking the link between the addiction to nicotine and the harms caused by smoking. First, the addictive potential of cigarettes could be minimized by requiring a large reduction in the nicotine content of cigarettes. Evidence for a nicotine reduction policy thus far shows that the use of very low nicotine content cigarettes results in a reduction in the number of cigarettes people smoke per day and a reduction in cigarette dependence. Second, emerging alternative nicotine delivery systems (ANDS) like electronic cigarettes may provide sufficient nicotine to act as substitutes for cigarettes while delivering much lower levels of toxicants. Evidence suggests that the emergence of ANDS has increased the percentage of smokers who are able to quit. The present paper will briefly review the evidence for each of these approaches, and consider what contemporary reinforcement and addiction theories can tell us about their likely success. We argue that the most effective endgame approach is one that pursues both nicotine reduction and alternative nicotine delivery systems as complementary.

Correlates of support for a nicotine-reduction policy in smokers with 6-week exposure to very low nicotine cigarettes

BACKGROUND

The US Food and Drug Administration recently issued an advanced notice of proposed rule-making for reducing the nicotine content in cigarettes to a minimally addictive level. Very little is known about whether use of very low nicotine content (VLNC) cigarettes affects support for a nicotine reduction policy.

OBJECTIVE

This study examined the effects of using VLNC versus usual brand (UB) cigarettes on support for a nicotine reduction policy and determined whether participant characteristics and responses to VLNC cigarettes were associated with policy support.

METHODS

Participants from a cigarette trial who were assigned to either 0.4 mg nicotine/g tobacco research cigarettes or their UB for 6 weeks were asked about their support for the policy. χ² tests were used to compare support for the policy between cigarette conditions and logistic regression analyses were conducted to assess covariates associated with policy support.

FINDINGS

Policy support did not differ by condition. After 6 weeks of using VLNC cigarettes, 50% of participants supported the policy, 26% opposed and 24% responded 'Don't Know'. Support was higher among those adherent to smoking only VLNC cigarettes (65%) compared with those who were non-adherent (44%). Older participants and those interested in quitting had increased odds of support. Cigarette satisfaction, perceived harm and perceived nicotine content were not significantly associated with support.

CONCLUSIONS

Smoking VLNC cigarettes did not affect support for a nicotine reduction policy. Understanding predictors of policy support and opposition will help public health officials to maximise the public health acceptance and impact of this policy (ClinicalTrials.gov Identifier: NCT01681875 Post-Results).

Nondaily Smokers' Changes in Cigarette Consumption With Very Low-Nicotine-Content Cigarettes: A Randomized Double-blind Clinical Trial

IMPORTANCE

The US Food and Drug Administration is considering limiting cigarettes to very low nicotine levels. Cigarette consumption of nondaily intermittent smokers (ITS), who compose one-third of US adult smokers, could feasibly increase or could be unaffected if their smoking is not motivated by nicotine seeking.

OBJECTIVE

To compare cigarette consumption in ITS receiving very low-nicotine-content cigarettes (VLNCCs) or identical normal-nicotine-content cigarettes (NNCCs).

DESIGN, SETTING, AND PARTICIPANTS

This randomized double-blind clinical trial was conducted from June 2015 to July 2017 at a single US site. Volunteer ITS not planning to quit were recruited via media. Overall, 297 individuals enrolled, and 238 were randomized. Analyses were intent-to-treat.

INTERVENTIONS

After a 2-week baseline of smoking their own brand of cigarettes provided gratis, ITS were randomized to VLNCCs or NNCCs for 10 weeks.

MAIN OUTCOMES AND MEASURES

The number of cigarettes per day (CPD) was assessed by real-time reporting, timeline follow-back reports, and cigarette butt counts. The primary outcome was change in CPD from baseline to weeks 9 to 10 of intervention, adjusting for baseline CPD.

RESULTS

The mean (SD) age of the 238 randomized participants was 37.9 (13.8) years. Of 238 participants, 108 (45%) were men. At baseline, the mean (SD) CPD was 3.1 (2.9). In intent-to-treat analyses using multiple imputation to address missing data, the VLNCC group had a mean decrease of 1.6 CPD (95% CI, 1.1-2.0; 51% of baseline) vs 0.05 decrease with NNCCs (95% CI, -0.5 to 0.4; 2% of baseline). Treatment group differences were not materially moderated by sex, race/ethnicity, or history of daily smoking. Cheating with conventional cigarettes, inferred from cotinine assays, was more common in the VLNCC group (OR, 2.95; 95% CI, 1.54-5.66), but sensitivity analyses showed significant VLNCC effects among the compliant participants as well. In longitudinal analysis of CPD over time with random intercept and slope, the VLNCC and NNCC groups differed significantly in both linear (-0.15; 95% CI, -0.22 to -0.08; P < .001) and quadratic (0.0026; 95% CI, 0.0010-0.0042; P = .002) trends: CPD dropped by 43.8% in the VLNCC group over 4 weeks, then leveled off thereafter. Abstinence (intent-to-treat, biochemically verified) in weeks 9 to 10 postrandomization did not differ significantly by treatment group (VLNCC, 10.2% vs NNNC, 5.0%; P = .28).

CONCLUSIONS AND RELEVANCE

Switching to VLNCCs caused substantial smoking reduction among ITS but did not significantly increase abstinence. Response to a VLNCC intervention suggests that nicotine-seeking motivates ITS' smoking.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02228824.

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.

Association of Reduced Nicotine Content Cigarettes With Smoking Behaviors and Biomarkers of Exposure Among Slow and Fast Nicotine Metabolizers: A Nonrandomized Clinical Trial

IMPORTANCE

The US Food and Drug Administration (FDA) has announced its intention to reduce the nicotine content in combustible cigarettes but must base regulation on public health benefits. Fast nicotine metabolizers may be at risk for increased smoking following a national nicotine reduction policy. We hypothesized that using reduced nicotine content (RNC) cigarettes would be associated with increases in smoking behaviors and exposure among smokers with a fast-but not slow-nicotine-metabolite ratio (NMR).

OBJECTIVES

To examine the association of RNC cigarettes with smoking behaviors and biomarkers of exposure and to compare these associations in fast and slow metabolizers of nicotine based on the NMR.

DESIGN SETTING AND PARTICIPANTS

A 35-day, 3-period, within-participant nonrandomized clinical trial was conducted at an academic medical center in Philadelphia, Pennsylvania. A 5-day baseline period using the smokers' preferred brand of cigarettes was followed by 2 consecutive 15-day periods using free investigational RNC cigarettes. A total of 100 daily, non-treatment-seeking, nonmenthol cigarette smokers (59 fast, 41 slow metabolizers) were recruited from December 24, 2013, to December 2, 2015. Data analysis was performed from December 12, 2016, to January 3, 2018.

INTERVENTIONS

Two 15-day periods using cigarettes containing 5.2 mg (RNC1) and 1.3 mg (RNC2) of nicotine per gram of tobacco.

MAIN OUTCOMES AND MEASURES

Smoking behaviors (number of cigarettes per day [CPD], total puff volume) and biomarkers of exposure (carbon monoxide [CO], urine total nicotine equivalents [TNE], and 4-[methylnitrosamino]-1-[3-pyridyl]-1-butanol [NNAL]).

RESULTS

Smokers (73 [73.0%] men; 74 [74.0%] white; mean [SD] age, 43.02 [12.13] years; mean [SD] CPD, 17.31 [5.72]) consumed 2.62 (95% CI, 1.54-3.70) more CPD during the RNC1 period vs their preferred brand during baseline (P < .001) and approximated baseline CPD during the RNC2 period (mean difference, 0.96 [95% CI, -0.36 to 2.28]; P = .24). Additional outcome measures were lower during both RNC periods vs baseline (total puff volume, mean [95% CI]: RNC1, 537 mL [95% CI, 479-595 mL]; RNC2, 598 mL [95% CI, 547-649 mL] vs baseline, 744 mL [95% CI, 681-806 mL]; TNE, mean [95% CI]: RNC1, 30.9 nmoL/mg creatinine [95% CI, 26.0-36.6 nmoL/mg]; RNC2, 22.8 nmoL/mg creatinine [95% CI, 17.8-29.0 nmoL/mg] vs baseline, 54.6 nmoL/mg creatinine [95% CI, 48.1-62.1 nmoL/mg]; and NNAL, mean [95% CI]: RNC1, 229 pg/mg creatinine [95% CI, 189-277 pg/mg]; RNC2, 190 pg/mg creatinine [95% CI, 157-231 pg/mg] vs baseline, 280 pg/mg creatinine [95% CI, 231-339 pg/mg]; all P < .001). Carbon monoxide measures were similar across study periods (CO boost [SD], RNC1, 4.6 ppm [4.1-5.1 ppm]; RNC2, 4.2 ppm [3.7-4.6 ppm]; and baseline, 4.4 ppm [3.8-4.9 ppm]). The RNC cigarette associations did not differ by NMR.

CONCLUSIONS AND RELEVANCE

Both RNC cigarettes were associated with decreased puffing and urinary biomarker exposure but not with decreased daily cigarette consumption or CO levels. The NMR did not moderate associations at the nicotine levels tested, suggesting that fast metabolizers may not be at greater risk of increasing use or exposure from these products should the FDA mandate an RNC standard for cigarettes.

Adolescent smokers' response to reducing the nicotine content of cigarettes: Acute effects on withdrawal symptoms and subjective evaluations

BACKGROUND

Mandating a reduction in the nicotine content of cigarettes to a minimally addictive level could dramatically reduce smoking rates in the US. However, little is known about the effects of reduced nicotine content cigarettes in adolescents.

METHODS

Following overnight abstinence, adolescent daily smokers (ages 15-19, n = 50) reported on their craving, withdrawal, and positive and negative affect pre- and post- ad lib smoking of one cigarette containing varying nicotine content (15.8, 5.2, 1.3 and 0.4 mg/g of tobacco) in the laboratory and reported their subjective evaluations of each cigarette. Carbon monoxide (CO) boost from pre- to post-cigarette was calculated to determine if lower-nicotine cigarettes led to differential acute changes in toxicant exposure.

RESULTS

All four nicotine cigarette types significantly reduced abstinence-induced craving, withdrawal, and negative affect (all p's < .05). Mixed models evaluating the effect of nicotine content, with nicotine dependence level and gender included as covariates, revealed a significant effect of nicotine content on craving and subjective evaluations: higher nicotine content resulted in greater reductions in craving and increases in both positive and negative subjective evaluations. There were no significant effects of nicotine dose on withdrawal symptoms, negative affect, or CO boost.

CONCLUSIONS

These results suggest that lower nicotine cigarettes might result in reduced abuse liability compared to higher nicotine content cigarettes due to reduced positive subjective effects, while still reducing withdrawal, in adolescents. These results highlight the potential feasibility of this policy approach and support continued research on how a nicotine reduction policy may affect adolescent smoking patterns.

Effects of reduced nicotine content cigarettes on individual withdrawal symptoms over time and during abstinence

In the United States, the Food and Drug Administration (FDA) has initiated a public dialogue about reducing the nicotine content of cigarettes. A reduced-nicotine standard could increase withdrawal symptoms among current smokers. We examined the impact of switching smokers to cigarettes that varied in nicotine content on withdrawal symptoms over 6 weeks. A secondary analysis (N = 839) of a 10-site, double-blind clinical trial of nontreatment-seeking smokers was completed. Participants were instructed to smoke study cigarettes, containing 0.4 to 15.8 mg of nicotine/g of tobacco, for 6 weeks and were then abstinent overnight. Using latent growth curves, trajectories of individual withdrawal symptoms were compared between the reduced nicotine content (RNC) conditions and a normal nicotine content (NNC) condition. Path analyses compared symptoms after overnight abstinence. Relative to NNC cigarettes, participants smoking RNC cigarettes had increased anger/irritability/frustration and increased appetite/weight gain during the initial weeks, but the symptoms resolved by Week 6. Individuals who were biochemically verified as adherent with using only the 0.4 mg/g cigarettes had higher sadness levels (Cohen's d = .40) at Week 6 compared with the NNC condition, although symptoms were mild. After a post-Week 6 overnight abstinence challenge, some RNC conditions relative to NNC condition exhibited reduced withdrawal. Individuals who were biochemically confirmed as adherent to the lowest nicotine condition experienced only mild and transient symptom elevations. Thus, a reduced-nicotine standard for cigarettes produced a relatively mild and temporary increase in withdrawal among nontreatment-seeking smokers (ClinicalTrials.gov No. NCT01681875). (PsycINFO Database Record

Cigarette Management System: An operating procedures guide to obtaining and managing investigational tobacco products for regulatory science research

Investigational tobacco products, specifically variable nicotine content research cigarettes (SPECTRUM), are available through the National Institute of Drug Abuse Drug Supply Program. Randomized controlled trials using research cigarettes are intended to support tobacco regulatory science research. The current paper provides an in-depth look into managing research cigarettes for two multi-site clinical trials and the design of a computer-based Cigarette Management System (CMS). The paper provides guidance intended for any investigator using similar products on the operating procedures under Good Clinical Practice standards and describes features of the CMS. The CMS and procedures described have been field tested for the past three years and have dispensed over 160,000 cigarette packs to participants. The CMS can accommodate a range of practical issues with real-world study implementation making it a robust application that is scalable to any study.

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.

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

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

Low Nicotine Content Descriptors Reduce Perceived Health Risks and Positive Cigarette Ratings in Participants Using Very Low Nicotine Content Cigarettes

INTRODUCTION

Understanding how smokers perceive reduced nicotine content cigarettes will be important if the FDA and global regulatory agencies implement reduced nicotine product standards for cigarettes. Prior research has shown that some smokers incorrectly believe "light" cigarettes are less harmful than regular cigarettes. Similar misunderstandings of health risk could also apply to reduced nicotine cigarettes. To date, most studies of reduced nicotine cigarettes have blinded subjects to the nicotine content. Therefore, little is known about how smokers experience reduced nicotine content cigarettes when they are aware of the reduced content, and how use may be impacted.

METHODS

The present study was a within-subjects experiment with 68 adult daily smokers who smoked two identical very low nicotine content Quest 3 (0.05 mg nicotine yield) cigarettes. Subjects were told that one cigarette contained "average" nicotine content, and the other contained "very low" nicotine content. After smoking each cigarette, subjects completed subjective measures about their smoking experience.

RESULTS

Subjects rated the "very low" nicotine cigarette as less harmful to their health overall compared to the "average" nicotine cigarette; this effect held true for specific smoking-related diseases. Additionally, they rated the "very low" nicotine cigarette as having less desirable subjective effects than the "average" nicotine cigarette and predicted having greater interest in quitting smoking in the future if only the "very low" nicotine cigarette was available.

CONCLUSIONS

Explicit knowledge of very low nicotine content changes smokers' perceptions of very low nicotine content cigarettes, resulting in reduced predicted harm, subjective ratings and predicted future use.

IMPLICATIONS

Before a reduced nicotine product standard for cigarettes can be implemented, it is important to understand how product information impacts how smokers think about and experience very low nicotine content cigarettes. Prior research has shown that smokers incorrectly believed light cigarettes were less harmful products. As such, smokers may also misunderstand the health risks associated with smoking very low nicotine content cigarettes. This study highlights the importance of smokers' perceptions of nicotine content in cigarettes on the perceived health risks and the subjective effects of smoking very low nicotine content cigarettes.

Perceived nicotine content of reduced nicotine content cigarettes is a correlate of perceived health risks

BACKGROUND

Reducing cigarette nicotine content may reduce smoking. Studies suggest that smokers believe that nicotine plays a role in smoking-related morbidity. This may lead smokers to assume that reduced nicotine means reduced risk, and attenuate potential positive effects on smoking behaviour.

METHODS

Data came from a multisite randomised trial in which smokers were assigned to use cigarettes varying in nicotine content for 6 weeks. We evaluated associations between perceived and actual nicotine content with perceived health risks using linear regression, and associations between perceived nicotine content and perceived health risks with smoking outcomes using linear and logistic regression.

FINDINGS

Perceived-not actual-nicotine content was associated with perceived health risks; compared with those perceiving very low nicotine, individuals who perceived low (β=0.72, 95% CI 0.26 to 1.17), moderate (β=1.02, 95% CI 0.51 to 1.53) or high/very high nicotine (β=1.66, 95% CI 0.87 to 2.44) perceived greater health risks. Nevertheless, individuals perceiving low (OR=0.48, 95% CI 0.32 to 0.71) or moderate nicotine (OR=0.42, 95% CI 0.27 to 0.66) were less likely than those perceiving very low nicotine to report that they would quit within 1 year if only investigational cigarettes were available. Lower perceived risk of developing other cancers and heart disease was also associated with fewer cigarettes/day at week 6.

CONCLUSIONS

Although the perception of reduced nicotine is associated with a reduction in perceived harm, it may not attenuate the anticipated beneficial effects on smoking behaviour. These findings have implications for potential product standards targeting nicotine and highlight the need to clarify the persistent harms of reduced nicotine combusted tobacco products.

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.

Attrition during a randomized controlled trial of reduced nicotine content cigarettes as a proxy for understanding acceptability of nicotine product standards

AIMS

To determine (1) if nicotine content affects study attrition-a potential behavioral measure of acceptability-in a trial that required compliance with three levels of reduced nicotine content (RNC) cigarettes, and (2) if attrition is associated with subjective and behavioral responses to RNC cigarettes.

DESIGN

Secondary analysis of a 35-day, parallel-design, open-label, randomized controlled trial. After a 5-day baseline period, participants were randomized to smoke for three 10-day periods: their preferred brand (control group) or RNC cigarettes with three nicotine levels in a within-subject stepdown (one group: high-moderate-low) or non-stepdown (five groups: high-low-moderate, low-moderate-high, low-high-moderate, moderate-low-high, moderate-high-low) fashion.

SETTING

A single site in Philadelphia, PA, USA.

PARTICIPANTS

A total of 246 non-treatment-seeking daily smokers [mean age = 39.52, cigarettes per day (CPD) = 20.95, 68.3% white] were recruited from October 2007 to June 2013.

MEASUREMENTS

The primary outcome was attrition. Key predictors were nicotine content transition and study period. Exploratory predictors were taste and strength subjective ratings, total puff volume and carbon monoxide (CO) boost. Covariates included: age, gender, race, education and nicotine dependence.

FINDINGS

Overall attrition was 31.3% (n = 77): 24.1% of the control and 25.0% of the stepdown RNC cigarette groups dropped out versus 44.6% of non-stepdown groups (P = 0.006). Compared with controls, attrition odds were 4.5 and 4.7 times greater among smokers transitioning from preferred and the highest RNC cigarettes to the lowest RNC cigarettes, respectively (P = 0.001 and 0.003). Providing more favorable initial taste ratings of study cigarettes decreased attrition odds by 2% (P = 0.012).

CONCLUSIONS

The majority of participants completed a 35-day trial of varying levels of reduced nicotine content cigarettes. Participant dropout was greater for cigarettes with lower nicotine content and less in smokers reporting more favorable subjective ratings of the cigarettes.

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.

Reduced nicotine content cigarette advertising: How false beliefs and subjective ratings affect smoking behavior

INTRODUCTION

Tobacco advertising can create false beliefs about health harms that are reinforced by product design features. Reduced nicotine content (RNC) cigarettes may reduce harm, but research has not addressed advertising influences. This study examined RNC cigarette advertising effects on false harm beliefs, and how these beliefs - along with initial subjective ratings of RNC cigarettes - affect subsequent smoking behaviors. We further explored whether subjective ratings moderate associations between false beliefs and behavior.

METHODS

Seventy-seven daily, non-treatment-seeking smokers (66.2% male) participated in the first 15days of a randomized, controlled, open-label RNC cigarette trial. Participants viewed an RNC cigarette advertisement at baseline before completing a 5-day period of preferred brand cigarette use, followed by a 10-day period of RNC cigarette use (0.6mg nicotine yield). Participants provided pre- and post-advertisement beliefs, and subjective ratings and smoking behaviors for cigarettes smoked during laboratory visits.

RESULTS

Viewing the advertisement increased beliefs that RNC cigarettes contain less nicotine and are healthier than regular cigarettes (p's<0.001 and 0.011), and decreased the belief that they are less likely to cause cancer (p=0.046). Neither false beliefs nor subjective ratings directly affected smoking behaviors. Significant interactions of strength and taste ratings with beliefs (p's<0.001), however, indicated that among smokers with less negative initial subjective ratings, greater false beliefs were associated with greater RNC cigarette consumption.

CONCLUSIONS

Smokers may misconstrue RNC cigarettes as less harmful than regular cigarettes. These beliefs, in conjunction with favorable subjective ratings, may increase product use.

U.S. adults' addiction and harm beliefs about nicotine and low nicotine cigarettes

This research described U.S. adults' beliefs about nicotine and low nicotine cigarettes (LNCs) using the nationally-representative Health Information National Trends Survey (HINTS-FDA 2015; N=3738). About three quarters of people either were unsure of the relationship between nicotine and cancer or incorrectly believed that nicotine causes cancer. People who were non-White, less educated, age 65+, and never established smokers were most likely to be unaware that nicotine is not a cause of cancer. More than a quarter of people held the potentially inaccurate beliefs that LNCs would be less harmful and addictive than typical cigarettes. Whites were more likely than Blacks to believe LNCs were less harmful than typical cigarettes, and never smokers were more likely to believe this than established quitters. Whites and people with at least a college degree were more likely to believe that LNCs would be less addictive than typical cigarettes. Overall, we found that many people, particularly the demographic subgroups identified here, held incorrect beliefs about nicotine and potentially inaccurate beliefs about LNCs. Findings should be considered in assessing the public health impact of marketing low nicotine products. Incorrectly believing that nicotine causes cancer could discourage smokers from switching to safer nicotine-containing alternatives, and could lead nonsmokers to experiment with low nicotine tobacco products, believing that cancer risk would be reduced. Findings underscore the need to educate the public on the health effects of nicotine and LNCs, and can help public health practitioners determine which subgroups should be prioritized in targeted educational efforts.

Chemical Characterization of Mainstream Smoke from SPECTRUM Variable Nicotine Research Cigarettes

OBJECTIVE

Our objective was to characterize mainstream smoke constituent deliveries from SPECTRUM variable nicotine research cigarettes under 2 machine smoking regimens. SPECTRUM cigarettes are manufactured by the 22nd Century company for the National Institute on Drug Abuse, National Institutes of Health to contain varying (including reduced) levels of nicotine.

METHODS

Mainstream smoke constituent deliveries of "tar," nicotine, carbon monoxide, tobacco-specific nitrosamines (N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)), benzo[a]pyrene, aromatic amines, and carbonyls were analyzed in 23 varieties of SPECTRUM cigarettes using ISO 17025 accredited methods.

RESULTS

Data are presented as means and standard deviations of 5 replicates for all analytes.

CONCLUSIONS

Under the ISO smoking regimen, mean levels of many smoke emissions for SPECTRUM varieties were comparable to the 3R4F research cigarette. Calculated SPECTRUM elasticity ranged from 1.6 to 4.0. Accordingly, under intense machine smoking conditions differences in emissions of SPECTRUM cigarettes were apparent. In addition, NNN increased with smoke nicotine while the same rate of change was not seen for NNK. It is important to monitor levels of chemicals of public health concern and regulatory interest as technologies emerge to reduce levels of nicotine or other targeted chemicals in tobacco products.

Reduced nicotine content cigarettes and use of alternative nicotine products: exploratory trial

AIMS

To compare the use of alternative nicotine products, smoking behavior and tobacco biomarker exposure in smokers unwilling to quit who were assigned randomly to normal nicotine content (NNC) cigarettes or very low nicotine content (VLNC) cigarettes.

DESIGN

Randomized, parallel-arm 8-week study with assignment to VLNC (VLNC 1, n = 53) or NNC (NNC, n = 27) with access to non-cigarette combusted and non-combusted tobacco/nicotine products or to VLNC with access to only non-combusted products (VLNC2, n = 56).

SETTING

Clinics in Minnesota, USA.

PARTICIPANTS

Smokers uninterested in quitting smoking with a mean [± standard deviation (SD)] age of 44 (± 14) years and smoking 16 (± seven) cigarettes/day; 51% female, 72% white.

MEASUREMENTS

During the experimental period, the measures taken included: rate of alternative products used, amount of and abstinence from combusted tobacco used and tobacco exposure biomarkers.

FINDINGS

There were higher rates of non-combusted alternative tobacco/nicotine product use in both VLNC conditions versus the NNC condition [rate ratio (RR) = 2.18, 95% confidence interval (CI) = 1.94, 2.46 and RR = 1.64, 95% CI = 1.46, 1.85, respectively] and in VLNC1 versus VLNC2 condition (RR = 1.33, 95% CI = 1.23, 1.44), accompanied by reduced biomarkers of exposure primarily in VLNC2 condition compared to NNC condition (Ps < 0.05). Fewer combusted products were smoked at almost all visits (Ps ≤ 0.02) and there were higher rates of abstinence for both VLNC conditions compared with the NNC condition (VLNC1 versus NNC: RR = 9.96, 95% CI = 5.01, 19.81; VLNC2 versus NNC: RR = 11.23, 95% CI = 5.74, 21.97).

CONCLUSION

The offer of, and instructions to use, reduced nicotine content cigarettes during an 8-week period led to greater use of alternative tobacco/nicotine products compared with continued use of normal nicotine cigarettes and also reductions in smoking rates.

Estimations and predictors of non-compliance in switchers to reduced nicotine content cigarettes

BACKGROUND AND AIMS

Clinical trials on the impact and safety of reduced nicotine content cigarettes (RNCs) are ongoing, and an important methodological concern is participant compliance with smoking only RNCs. Our aims were to measure non-compliance biochemically with urine cotinine (COT) and total nicotine equivalents (TNEs), compare with self-reported non-compliance and identify associated covariates.

DESIGN

Secondary analysis of a double-blind, parallel, randomized clinical trial.

SETTING

Research centers from the United States, enrolling participants from June 2013 to July 2014.

PARTICIPANTS

Volunteer sample of 242 participants (55% Caucasian), average age of 41.2 years, smoking at least five cigarettes per day (CPD).

INTERVENTION

Smoking very low nicotine cigarettes (VLNCs; 0.4 mg nicotine/g tobacco) for 6 weeks.

MEASUREMENTS

The primary outcome was biochemically verified non-compliance, measured as thresholds of COT/CPD and TNE/CPD ratios, considering changes in nicotine content from conventional levels to VLNCs, and as an absolute threshold of week 6 TNEs. Self-reported non-compliance was measured via daily phone calls. Key predictors included age, sex, race, menthol preference, nicotine metabolite ratio, time to first cigarette, dependence, CPD, TNEs, tar level and cigarette evaluation.

FINDINGS

Estimates of non-compliance with smoking the VLNCs exclusively include: the biochemical ratios (both 78%), the week 6 TNE threshold (76%) and self-report (39%). Of the key covariates, age, dependence and cigarette evaluations of satisfaction were significant; for age, younger participants more likely to be non-compliant [P = 0.01; odds ratio (OR) = 0.98, 95% confidence interval (CI) = 0.96-0.99]. Dependence was associated significantly with self-reported non-compliance (P = 0.01; OR = 1.28, 95% CI = 1.06-1.55). Cigarette evaluations of satisfaction were associated significantly with non-compliance (P = 0.001; OR = 0.71, 95% CI = 0.61-0.82).

CONCLUSIONS

Among smokers volunteering to smoke only very low nicotine cigarettes for 6 weeks, non-compliance was common and biochemical assessments detected more cases of non-compliance than self-report. Despite high levels of non-compliance, smokers reduced their intake of nicotine by an average of 60%.

Reduced Nicotine Content Expectancies Affect Initial Responses to Smoking

OBJECTIVES

We sought to determine if negative responses to reduced nicotine content (RNC) cigarettes during open-label trials result from smokers' (negative) expectancies. We examined the effects of nicotine content description - independent of actual nicotine content - on subjective responses (craving reduction, withdrawal suppression, mood changes, and sensory ratings) and smoking behaviors (topography measures and carbon monoxide [CO] boost).

METHODS

Thirty-six 12-hour-abstinent daily smokers completed a 3-session crossover trial. During each session, participants smoked their preferred brand cigarette - blinded and described as containing "usual," "low," and "very low" nicotine content - through a topography device and completed CO and subjective response assessments.

RESULTS

Although nicotine content was identical, compared to the "usual" content cigarette, participants experienced less craving reduction after smoking the "very low" nicotine cigarette, and rated its smoke as weaker (p < .05). Participants took shallower puffs of the "low" nicotine cigarette (p < .05), and rated the "low" and "very low" nicotine cigarettes as weaker and too mild (p < .01).

CONCLUSIONS

Negative responses to RNC cigarettes may be due, in part, to negative expectancies about using cigarettes containing less nicotine. In this context, RNC cigarette marketing and labeling are likely important considerations if a federal nicotine reduction policy is initiated.

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.