Parameter Space and Potential for Biomarker Development in 25 Years of fMRI Drug Cue Reactivity: A Systematic Review

Importance

In the last 25 years, functional magnetic resonance imaging drug cue reactivity (FDCR) studies have characterized some core aspects in the neurobiology of drug addiction. However, no FDCR-derived biomarkers have been approved for treatment development or clinical adoption. Traversing this translational gap requires a systematic assessment of the FDCR literature evidence, its heterogeneity, and an evaluation of possible clinical uses of FDCR-derived biomarkers.

Objective

To summarize the state of the field of FDCR, assess their potential for biomarker development, and outline a clear process for biomarker qualification to guide future research and validation efforts.

Evidence Review

The PubMed and Medline databases were searched for every original FDCR investigation published from database inception until December 2022. Collected data covered study design, participant characteristics, FDCR task design, and whether each study provided evidence that might potentially help develop susceptibility, diagnostic, response, prognostic, predictive, or severity biomarkers for 1 or more addictive disorders.

Findings

There were 415 FDCR studies published between 1998 and 2022. Most focused on nicotine (122 [29.6%]), alcohol (120 [29.2%]), or cocaine (46 [11.1%]), and most used visual cues (354 [85.3%]). Together, these studies recruited 19 311 participants, including 13 812 individuals with past or current substance use disorders. Most studies could potentially support biomarker development, including diagnostic (143 [32.7%]), treatment response (141 [32.3%]), severity (84 [19.2%]), prognostic (30 [6.9%]), predictive (25 [5.7%]), monitoring (12 [2.7%]), and susceptibility (2 [0.5%]) biomarkers. A total of 155 interventional studies used FDCR, mostly to investigate pharmacological (67 [43.2%]) or cognitive/behavioral (51 [32.9%]) interventions; 141 studies used FDCR as a response measure, of which 125 (88.7%) reported significant interventional FDCR alterations; and 25 studies used FDCR as an intervention outcome predictor, with 24 (96%) finding significant associations between FDCR markers and treatment outcomes.

Conclusions and Relevance

Based on this systematic review and the proposed biomarker development framework, there is a pathway for the development and regulatory qualification of FDCR-based biomarkers of addiction and recovery. Further validation could support the use of FDCR-derived measures, potentially accelerating treatment development and improving diagnostic, prognostic, and predictive clinical judgments.

Developing a shared understanding of translational science within CTSA hubs through facilitated retreats: A case study

Translation of critical and broadly impactful health advancements is stymied by insufficient scientific scrutiny of barriers and roadblocks in the process. The Clinical & Translational Science Award (CTSA) funding opportunity announcement released in July 2021 makes clear the distinction between translational research and translational science (TS) and urges a shift from the former to the latter. This represents a significant shift in the overall scientific direction of the CTSA program and necessitates corresponding shifts in CTSA hub operations. To better support TS, the Team Science Core of the Duke CTSA hub designed and facilitated a virtual retreat for hub personnel that (1) enabled organizational learning about TS and (2) identified anticipated challenges and opportunities. A post-retreat survey was utilized to assess the degree to which the retreat met its stated goals. Our survey received a 62% response rate; 100% of respondents would recommend the session to others. Respondents also reported gains in all areas assessed, with evidence for greater understanding of TS and increased perspective of the value and relevance of TS. In this paper, we provide a roadmap for designing and implementing facilitated TS retreats, which we argue is a key step in TS capacity building through workforce development.

Differences in Normative Beliefs and Tobacco Product Use by Age Among Adults Who Smoke: Cross-Sectional Analysis of a Nationally Representative Sample

BACKGROUND

The prevalence of combusted cigarette (CC) smoking among older adults is stagnant, with 0 declines attributable to e-cigarette (EC) use. Given that normative beliefs are associated with quitting and switching to ECs, we assessed cross-sectional associations between age, CC, and EC descriptive and injunctive norms and potential interactions with tobacco use behavior.

METHODS

Data are from people with current, established (≥100 lifetime CCs) CC use (n = 8072) at Wave 5 (2018-2019) of the adult Population Assessment of Tobacco and Health Study. We used adjusted multivariable logistic regressions to model social norms as a function of age (18-24, 25-34, 35-44, 45-54, 55-64, ≥65 years). We also dichotomized age (≥55 vs 18-54) to investigate interactions between age and social norms on past 12-month CC quit attempts and past-month EC use.

RESULTS

Older age was positively associated with pro- and anti-CC norms and anti-EC norms. Significant interactive effects revealed that being advised to quit smoking by a healthcare provider was more strongly associated with CC quit attempts among adults ≥55 years (adjusted odds ratio [aOR] [95% CI]: 2.12 [1.66, 2.71]) than adults <55 years (aOR: 1.63 [1.34, 2.00]). Reporting people close to you use ECs was also more strongly associated with EC use among adults ≥55 years (aOR: 4.37 [3.35, 5.69]) than among adults <55 years (aOR: 3.43 [2.89, 4.08]).

CONCLUSIONS

This study identified modifiable risk factors for tobacco use that may be particularly beneficial for older adults. Behavioral and communication interventions that target normative beliefs may maximize smoking cessation, or harm reduction when cessation is not possible.

Pain is associated with exclusive use and co-use of tobacco and cannabis: Findings from Wave 5 (2018-2019) of the Population Assessment of Tobacco and Health Study

INTRODUCTION

Rates of tobacco and cannabis use are disproportionately high among individuals with pain, and evidence suggests that pain may engender greater likelihood of substance co-use, yielding additive risk. This study examined national associations of pain with past-month tobacco use, cannabis use, and co-use of tobacco and cannabis.

METHODS

Data came from a nationally representative US sample of adults in Wave 5 (2018-2019) of the Population Assessment of Tobacco and Health study (N = 32,014). The sample included civilian, non-institutionalized people who use tobacco and people who do not use tobacco. Past-week pain intensity (0-10) was dichotomized (0-4 no/low pain; 5-10 moderate/severe pain). Multinomial models adjusted for demographics examined substance use category membership (no tobacco or cannabis use, exclusive cannabis use, exclusive tobacco use, co-use) as a function of pain status.

RESULTS

Moderate/severe pain was associated with increased relative risk of exclusive tobacco use (RRR [CI] 2.26 [2.05, 2.49], p <.001), exclusive cannabis use (1.49 [1.22, 1.82], p <.001), and co-use of tobacco and cannabis (2.79 [2.51, 3.10], p <.001), in comparison to no tobacco or cannabis use. Additionally, moderate/severe pain was associated with increased risk of co-use compared to exclusive tobacco use (1.23 [1.11, 1.37], p <.001) and exclusive cannabis use (1.88 [1.54, 2.29], p <.001).

DISCUSSION

Findings suggest that not only is pain independently associated with greater risk of exclusively using tobacco or cannabis, but pain is also associated with heightened risk of co-using both products. Future work should examine the dynamic and potentially bidirectional relationships between pain and use of cannabis and tobacco.

Stagnant daily smoking prevalence between 2008 and 2019 among Black and Hispanic adults with serious psychological distress

BACKGROUND

Racial/ethnic minority status and mental illness independently drive inequity in cigarette smoking and related morbidity. Racial/ethnic minority groups suffer a disproportionate burden of tobacco-related diseases. People with serious mental illness (SMI) smoke at up to 7 times the rate of the general population. There is a need to quantify smoking prevalence and trends among people at the intersection of both groups.

METHODS

This study analyzes 2008-2019 data from the National Survey on Drug Use and Health. Linear time trends of daily smoking prevalence were assessed among people with serious psychological distress (SPD; marker for SMI) and people without SPD reporting White, Black, Hispanic, and Other race/ethnicity using logistic regression, with survey year as the predictor. Models with year-by-smoking status interaction terms and F-tests assessed differential time trends.

RESULTS

The prevalence of daily smoking among people without SPD decreased over time among people reporting White (aOR=0.96, p<0.001), Black (aOR=0.96, p<0.001), Hispanic (aOR=0.95, p<0.001), and Other (aOR=0.97, p=0.002) race/ethnicity. Among people with SPD, the smoking prevalence decreased among people with White race/ethnicity (aOR=0.95, p<0.001), with no significant changes among people of Black, Hispanic, and Other race/ethnicity.

CONCLUSIONS

Smoking among people with SPD who report Black and Hispanic race/ethnicity has not changed significantly in the past 11 years, despite decreasing among non-SPD and White groups. People who are Black/Hispanic and people with SPD struggle to quit smoking, which is amplified intersectionally. Tailored interventions may be a better mechanism to reduce barriers to smoking cessation in this population.

Older age is associated with greater misperception of the relative health risk of e-cigarettes and cigarettes among US adults who smoke

INTRODUCTION

The prevalence of cigarette smoking among adults aged ≥55 has remained stagnant over the past decade. National data modelling suggests no reduction in cigarette smoking prevalence attributable to e-cigarette use in the USA among people aged ≥45. Misperceptions about the absolute risks (ie, cigarettes are not harmful) and relative risks (ie, e-cigarettes are more harmful than cigarettes) of tobacco products may contribute to sustained smoking prevalence and hesitancy to switch from cigarettes to e-cigarettes among older adults.

METHODS

Participants reported cigarette use (n=8072) at Wave 5 (2018-2019) of the Population Assessment of Tobacco and Health Study. Weighted multivariable logistic regressions included six age categories (independent variable) and cigarette and e-cigarette risk perceptions (outcomes). Additional models assessed the associations between dichotomous age (≥55 vs 18-54), risk perceptions and an interaction term (independent variables) with past 12-month quit attempts and past-month e-cigarette use (outcomes).

RESULTS

Adults aged ≥65 were less likely than adults aged 18-24 to rate cigarettes as very/extremely harmful (p<0.05). Odds of rating e-cigarettes as more harmful than cigarettes among adults aged 55-64 and ≥65 were 1.71 (p<0.001) and 1.43 (p=0.024) greater than for adults aged 18-24. This misperception was negatively associated with past-month e-cigarette use and was stronger among adults aged ≥55 (p<0.001) than adults aged <55 (p<0.001).

DISCUSSION

Adults aged ≥55 are more likely to have misperceptions about the absolute and relative risks of tobacco products, which may contribute to continued smoking. Health communications targeting this age group could modify beliefs about the perceived harms of tobacco products.

Feasibility, Acceptability, and Preliminary Efficacy of a Gamified Mobile Health Contingency Management Intervention for PrEP Adherence Among Black MSM

Oral HIV pre-exposure prophylaxis (PrEP) is effective at preventing HIV. However, low adherence is common and undermines these protective effects. This is particularly relevant for groups with disproportionately higher rates of HIV, including Black men who have sex with men (MSM). The current study tested the feasibility, acceptability, and preliminary efficacy of a gamified mobile health contingency management intervention for PrEP adherence-called mSMART (Mobile App-Based Personalized Solutions for Medication Adherence of Rx Pill Tool). Fifteen Black MSM already prescribed PrEP in the community completed baseline and follow-up assessments separated by 8 weeks of using mSMART. Regarding feasibility, there was no study attrition, no mSMART functional difficulties that significantly interfered with use, and a mean rate of 82% daily mSMART use. Acceptability ratings were in the moderately to extremely satisfied range for factors such as willingness to recommend mSMART to others and user-friendliness, and in the low range for ratings on difficulty learning how to use mSMART. Scores on a system usability measure were in the acceptable range for 73% of the sample. Qualitative analysis of follow-up interviews identified individual components of mSMART that could be modified in future iterations to make it more engaging. PrEP composite adherence scores from biomarkers indicated an improvement from baseline to follow-up with a medium effect size, as well as a decrease in the number of perceived barriers to medication adherence. Findings indicate a future efficacy trial is needed to examine the effects of this gamified mobile health contingency management intervention on PrEP adherence.

Menthol preference moderates the relationship between cigarette nicotine content choice and reactions in young adults who smoke infrequently

BACKGROUND

Half of young adults who smoke use menthol cigarettes, which is associated with continued smoking and greater nicotine dependence. Additionally, early subjective reactions to cigarettes predict future use. Menthol may blunt the sensory effects of nicotine. We investigated the moderating role of menthol on subjective reactions to, and choice of varied nicotine content cigarettes in young adults who smoke infrequently.

METHODS

In three counterbalanced, double-blinded sessions, young adults who smoke ≤ 15 days/month smoked fixed doses from very low (VLNC), intermediate (INC), and normal (NNC) nicotine content cigarettes, which were menthol or non-menthol depending on preference. Participants chose their preferred cigarette in a final session. Positive and negative subjective reactions were measured in each session. ANOVA tests investigated the relationship between menthol preference, nicotine content, and subjective reactions.

RESULTS

Participants (N = 87) were 18-25 years old and reported smoking 15.2 cigarettes per month over 8 days (35 % menthol). Non-menthol preferring participants had increased negative reactions with greater nicotine content (F(1, 55)= 10.76, p < .001); menthol preferring participants did not. Choice of higher nicotine cigarettes was associated with having reported a greater difference in positive reactions to NNC and VLNC for non-menthol preferring participants (F(1, 55)= 12.72, p < .001) but not for menthol preferring participants.

CONCLUSIONS

Young adults who smoke infrequently are a priority tobacco control population given their high risk of transitioning to daily smoking. Results from this study in the form of subjective reactions indicate that a menthol ban is required for a nicotine reduction standard to be maximally effective in this vulnerable group.

Spatially Varying Associations of Neighborhood Disadvantage with Alcohol and Tobacco Retail Outlet Rates

More than 30% of cancer related deaths are related to tobacco or alcohol use. Controlling and restricting access to these cancer-causing products, especially in communities where there is a high prevalence of other cancer risk factors, has the potential to improve population health and reduce the risk of specific cancers associated with these substances in more vulnerable population subgroups. One policy-driven method of reducing access to these cancer-causing substances is to regulate where these products are sold through the placement and density of businesses selling tobacco and alcohol. Previous work has found significant positive associations between tobacco, alcohol, and tobacco and alcohol retail outlets (TRO, ARO, TARO) and a neighborhood disadvantage index (NDI) using Bayesian shared component index modeling, where NDI associations differed across outlet types and relative risks varied by population density (e.g., rural, suburban, urban). In this paper, we used a novel Bayesian index model with spatially varying effects to explore spatial nonstationarity in NDI effects for TROs, AROs, and TAROs across census tracts in North Carolina. The results revealed substantial variation in NDI effects that varied by outlet type. However, all outlet types had strong positive effects in one coastal area. The most important variables in the NDI were percent renters, Black racial segregation, and the percentage of homes built before 1940. Overall, more disadvantaged areas experienced a greater neighborhood burden of outlets selling one or both of alcohol and tobacco.

Multiple Tobacco Product Use Conceptual Framework: A 2021 Update on Evidence

INTRODUCTION

One-third of adults in the United States who use tobacco regularly use two or more types of tobacco products. As the use of e-cigarettes and other noncombusted tobacco products increases-making multiple tobacco product (MTP) use increasingly common-it is essential to evaluate the complex factors that affect product use.

AIMS AND METHODS

In this update to our 2019 conceptual framework, we review and evaluate recent literature and expand the model to include ways in which MTP use may be affected by market factors such as the introduction of new products and socioenvironmental factors like marketing and advertising.

RESULTS AND CONCLUSIONS

MTP use patterns are complex, dynamic, and multiply determined by factors at the level of individuals, products, situations or contexts, and marketplace. Substitution, or using one product with the intent of decreasing use of another, and complementarity, or using multiple products for different reasons or purposes, explain patterns in MTP use. Moreover, substitution and complementarity may inform our understanding of how market changes targeted at one product, for instance, new product standards, bans, product pricing, and taxation, affect consumption of other tobacco products. New data from natural experiments and novel laboratory-based techniques add additional data and expand the framework.

IMPLICATIONS

A substantial proportion of people who use tobacco use more than one product. This review synthesizes and evaluates recent evidence on the diverse factors that affect MTP use in addition to expanding our framework. Our review is accompanied by suggested research questions that can guide future study.

Associations of Alcohol and Tobacco Retail Outlet Rates with Neighborhood Disadvantage

Tobacco causes 29% of cancer-related deaths while alcohol causes 5.5% of cancer-related deaths. Reducing the consumption of these cancer-causing products is a special priority area for the National Cancer Institute. While many factors are linked to tobacco and alcohol use, the placement and density of retail outlets within neighborhoods may be one community-level risk factor contributing to greater use of these products. To elucidate associations between tobacco, alcohol, and tobacco and alcohol retail outlets (TRO, ARO, and TARO) and neighborhood disadvantage over a large geographic area, we employed a novel Bayesian index modeling approach to estimate a neighborhood disadvantage index (NDI) and its associations with rates of the three types of retailers across block groups in the state of North Carolina. We used a novel extension of the Bayesian index model to include a shared component for the spatial pattern common to all three types of outlets and NDI effects that varied by outlet type. The shared component identifies areas that are elevated in risk for all outlets. The results showed significant positive associations between neighborhood disadvantage and TROs (relative risk (RR) = 1.12, 95% credible interval (CI = 1.09, 1.14)) and AROs (RR = 1.15, 95% CI = 1.11, 1.17), but the association was greatest for TAROs (RR = 1.21, 95% CI = 1.18, 1.24). The most important variables in the NDI were percent renters (i.e., low home ownership), percent of homes built before 1940 (i.e., old housing stock), and percent without a high school diploma (i.e., low education).

Preliminary evaluation of short-term abstinence effects among never-smoking experienced users of modern electronic cigarettes

INTRODUCTION

ECIG use has increased among non-smokers, with the potential negative consequence of developing nicotine dependence. ECIG users report withdrawal symptoms upon abstinence, though the significance of these symptoms has been questioned. This preliminary study aimed to characterize the early timecourse of ECIG withdrawal under forced abstinence.

METHODS

Fifteen never-smoking ECIG users completed two conditions whereby participants either abstained from ECIG use (abstinence) or used their own ECIG (ad lib) for 3 hours. Puff topography in this latter condition was measured via video observation. Outcome measures included heart rate, subjective ratings of withdrawal, cognitive performance, and choice behavior.

RESULTS

Heart rate was lower during abstinence compared to ad lib use (F=12.60, p<.01, ƞp  2=0.47). Higher levels of craving (F=4.98, p<.05, ƞp  2=0.26) and lower levels of nicotine effects (e.g., dizzy, F=4.62, p<.05, ƞp  2=0.36) were reported during abstinence compared to ad lib use. Interaction effects were observed for both factors of the Questionnaire of Smoking Urges: Brief (Fs>3.56, ps<.05, ƞp  2s=0.21-0.27), with factor scores increasing from baseline to 90 minutes in the abstinent condition only. Inhibitory control was impaired at 120 min in the abstinent condition only (F=7.51, p<.05, ƞp  2=0.50).

CONCLUSIONS

Never-smoking ECIG users experienced aversive withdrawal symptoms within 2-3 hours of abstinence. Future work should include other control conditions, such as placebo ECIGs or nicotine replacement therapy, and biomarkers of nicotine exposure, as well as examine withdrawal as a function of device type.

IMPLICATIONS

Never-smoking ECIG users experience some aversive nicotine withdrawal symptoms within two to three hours of abstinence. Relative to ad lib ECIG use, abstinence decreased heart rate and inhibitory control, as well as increased subjective ratings of withdrawal such as craving and intention to vape. Those same symptoms might be suppressed by self-administration of ECIGs. Experiencing withdrawal upon abstinence may indicate that ECIGs can cause dependence without a history of other tobacco use.

Prediction of Smoking Risk From Repeated Sampling of Environmental Images: Model Validation

Background

Viewing their habitual smoking environments increases smokers’ craving and smoking behaviors in laboratory settings. A deep learning approach can differentiate between habitual smoking versus nonsmoking environments, suggesting that it may be possible to predict environment-associated smoking risk from continuously acquired images of smokers’ daily environments.

Objective

In this study, we aim to predict environment-associated risk from continuously acquired images of smokers’ daily environments. We also aim to understand how model performance varies by location type, as reported by participants.

Methods

Smokers from Durham, North Carolina and surrounding areas completed ecological momentary assessments both immediately after smoking and at randomly selected times throughout the day for 2 weeks. At each assessment, participants took a picture of their current environment and completed a questionnaire on smoking, craving, and the environmental setting. A convolutional neural network–based model was trained to predict smoking, craving, whether smoking was permitted in the current environment and whether the participant was outside based on images of participants’ daily environments, the time since their last cigarette, and baseline data on daily smoking habits. Prediction performance, quantified using the area under the receiver operating characteristic curve (AUC) and average precision (AP), was assessed for out-of-sample prediction as well as personalized models trained on images from days 1 to 10. The models were optimized for mobile devices and implemented as a smartphone app.

Results

A total of 48 participants completed the study, and 8008 images were acquired. The personalized models were highly effective in predicting smoking risk (AUC=0.827; AP=0.882), craving (AUC=0.837; AP=0.798), whether smoking was permitted in the current environment (AUC=0.932; AP=0.981), and whether the participant was outside (AUC=0.977; AP=0.956). The out-of-sample models were also effective in predicting smoking risk (AUC=0.723; AP=0.785), whether smoking was permitted in the current environment (AUC=0.815; AP=0.937), and whether the participant was outside (AUC=0.949; AP=0.922); however, they were not effective in predicting craving (AUC=0.522; AP=0.427). Omitting image features reduced AUC by over 0.1 when predicting all outcomes except craving. Prediction of smoking was more effective for participants whose self-reported location type was more variable (Spearman ρ=0.48; P=.001).

Conclusions

Images of daily environments can be used to effectively predict smoking risk. Model personalization, achieved by incorporating information about daily smoking habits and training on participant-specific images, further improves prediction performance. Environment-associated smoking risk can be assessed in real time on a mobile device and can be incorporated into device-based smoking cessation interventions.

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.

Appeal, subjective effects, and relative reinforcing effects of JUUL that vary in flavor and nicotine content

The U.S. Food and Drug Administration has the authority to regulate characteristics of electronic nicotine delivery systems (ENDS). Prior research indicates that regulation of certain characteristics of these products may have an effect on their appeal and use. Policies that affect appeal and use of ENDS are relevant to attempts to reduce use among young people-including young adults-but are also relevant to adults who use these products as harm reduction tools. Using a novel concurrent choice task, we evaluated the relative reinforcement of JUUL brand ENDS products that varied in flavor (n = 8) and nicotine (n = 8) among samples of young adults who use JUUL. Findings suggest that restricting JUUL flavor to tobacco-only results in decreased appeal, while reducing the nicotine content of JUUL pods to 3%-from the conventional 5%-does not have an effect on product appeal. Findings also validate a novel methodology for delivering fixed doses of ENDS vapor within the context of a task that assesses the relative reinforcement of ENDS products with varying characteristics. This methodology can be applied to assessing the relative reinforcing effects of a wide variety of tobacco products with varied characteristics. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Experiences With Smoking Cessation Attempts and Prior Use of Cessation Aids in Smokers With HIV: Findings From a Focus Group Study Conducted in Durham, North Carolina

Cigarette smoking remains disproportionately prevalent and is increasingly a cause of death and disability among people with HIV (PWH). Many PWH are interested in quitting, but interest in and uptake of first-line smoking cessation pharmacotherapies are varied in this population. To provide current data regarding experiences with and perceptions of smoking cessation and cessation aids among PWH living in Durham, North Carolina, the authors conducted five focus group interviews (total n = 24; 96% African American) using semistructured interviews. Interviews were recorded, transcribed, coded, and thematically analyzed. Major themes included ambivalence and/or lack of interest in cessation; presence of cessation barriers; perceived perceptions of ineffectiveness of cessation aids; perceived medication side effects; and conflation of the harms resulting from use of tobacco products and nicotine replacement therapy. Innovative and effective interventions must account for the aforementioned multiple barriers to cessation as well as prior experiences with and misperceptions regarding cessation aids.

Support for a nicotine reduction policy among participants enrolled in a 20-week trial of very low nicotine content cigarettes

INTRODUCTION

The Food and Drug Administration is considering a policy to drastically reduce the allowable nicotine content of cigarettes. The current study examined whether the policy implementation approach, i.e., either immediately reducing nicotine content to very low levels or gradually reducing nicotine content over an extended period, influences policy support among people who smoke cigarettes.

METHODS

Adults who smoked daily were randomly assigned (double-blind) to an immediate nicotine reduction condition (0.4 mg/g nicotine cigarettes), a gradual nicotine reduction condition (15.5 to 0.4 mg/g), or a control condition (15.5 mg/g) for 20 weeks. Participants were asked if they would "support or oppose a law that reduced the amount of nicotine in cigarettes, to make cigarettes less addictive." Logistic regression analyses assessed if policy support was affected by treatment condition, demographic covariates, interest in quitting, and subjective cigarette effects.

RESULTS

At Week 20 (N = 957 completers), 60.4% of participants supported the policy, 17.4% opposed, and 22.2% responded "Don't know." Policy support did not differ by treatment condition. Support was greater among those interested in quitting (OR = 3.37, 95% CI = 2.49, 4.55). Support was lower among males (OR = 0.49, 95% CI = 0.37, 0.67), those with greater dependence scores (OR = 0.92, 95% CI = 0.86, 0.99) and participants aged 18-24 (OR = 0.53, 95% CI = 0.28, 0.99). No other covariates were associated with policy support.

CONCLUSIONS

The majority of participants supported a nicotine reduction policy. The implementation approach, immediate or gradual reduction, did not affect policy support. Participants interested in quitting smoking were more likely to support a nicotine reduction policy.

Very Low Nicotine Content Cigarettes Disrupt the Feedback Loop of Affective States and Smoking Behavior

INTRODUCTION

Smoking to reduce negative affect has been identified as a key motivational feature of tobacco use. Our recent work suggests that smoking very low nicotine content (VLNC) cigarettes reduces the relationship between negative affect and smoking behavior over a 6-week period. Here, we sought to extend our findings by evaluating whether a gradual or immediate approach to switching to VLNC cigarettes led to a differential reduction in the relationship between affect and smoking behavior over a longer (20-week) period.

AIMS AND METHODS

Participants (n = 1250) were adult smokers from 10 US sites randomized to one of three groups: gradual nicotine reduction (15.5, 11.7, 5.2, 2.4, and 0.4 mg of nicotine per gram of tobacco [mg/g]), immediate nicotine reduction (0.4 mg/g), or standard nicotine content cigarettes (15.5 mg/g; control), for 20 weeks. We examined whether the relationship between affect-both negative and positive-and cigarettes per day differed as a function of reduction group.

RESULTS

We found that both negative and positive affect were associated with cigarette consumption in the control group, but not in the gradual or immediate reduction groups across the 20 weeks of exposure.

CONCLUSIONS

Our results extend previous findings that switching to VLNC cigarettes disrupts the relationship between affect and cigarette consumption by showing that either gradually or immediately reducing cigarette nicotine content achieves this disruption. These findings provide further evidence that switching to VLNC cigarettes reduces nicotine-related reinforcement of cigarette smoking.

IMPLICATIONS

These findings support the notion that switching to very low nicotine content cigarettes reduces the association between affect and smoking behavior, and that either a gradual or immediate nicotine reduction approach achieves this reduction. This provides further evidence that switching to very low nicotine content cigarettes weakens reinforcement mechanisms associated with nicotine dependence.

Risk perceptions regarding cigarette smoking in the United States continue to decline

Nationally representative data from the years 2006-2015 indicate that the prevalence of perceived great risk of smoking one or more packs of cigarettes per day has declined significantly among the United States general population. These findings have important implications for initiation of cigarette smoking, as well as interest in quitting, quit attempts, and sustained cessation. Findings based on more recent data (i.e., years 2016-2018) show that the prevalence of perceived great risk of cigarette smoking has continued to decline significantly (71.76 % versus 72.77 % in 2016 and 73.89 % in 2006). We aim to draw attention to this continued decline in risk perceptions, particularly given the possible associated public health impacts.

Increased subjective and reinforcing effects of initial nicotine exposure in young adults with attention deficit hyperactivity disorder (ADHD) compared to matched peers: results from an experimental model of first-time tobacco use

Individuals with attention deficit hyperactivity disorder (ADHD) are at increased risk for adverse cigarette smoking outcomes, and little is known about factors underlying this risk. This study sought to evaluate the effects of initial nicotine exposure in young adults with and without ADHD using a novel paradigm of exposure to model initial smoking experiences. Participants were young adult nonsmokers (n = 61 ADHD, n = 75 Control) between the ages of 18-25 years (inclusive) who reported never having smoked a full cigarette, and no tobacco use in the prior 3 years. Participants were exposed to three different blinded doses of intranasally administered nicotine (0, 0.5, 1.0 mg) across three separate fixed dose experimental sessions. In subsequent sessions, participants were given the opportunity to self-administer nicotine under two different conditions-high and low cognitive demand. Physiological, subjective, and reinforcing effects of nicotine were the main outcomes. Nicotine plasma levels, and no group differences in effects of nicotine on heart rate or blood pressure, confirmed comparable dosing exposure across groups. ADHD participants reported significantly greater dizziness following nicotine, and greater pleasant subjective effects across all conditions, compared to non-ADHD non-smokers. There were no group differences on subjective reports of bad or unpleasant effects. Subsequent nicotine self-administration was significantly higher among non-smokers with ADHD, and their choices of nicotine were not influenced by cognitive condition. There are meaningful differences between young adults with and without ADHD with respect to the initial subjective and reinforcing effects of nicotine; and interventions to prevent use should start prior to typical age of experimentation among ADHD patients.

Digital envirotyping: quantifying environmental determinants of health and behavior

Digital phenotyping efforts have used wearable devices to connect a rich array of physiologic data to health outcomes or behaviors of interest. The environmental context surrounding these phenomena has received less attention, yet is critically needed to understand their antecedents and deliver context-appropriate interventions. The coupling of improved smart eyewear with deep learning represents a technological turning point, one that calls for more comprehensive, ambitious study of environments and health.

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.

Anticipated Effects of Nicotine Reduction on Youth Smoking Initiation and Maintenance

This commentary summarizes emerging findings on the potential impact of a nicotine reduction policy on youth and young adults. We conclude that: (1) adolescent smokers and nonsmokers alike are likely to be less sensitive to reinforcement from very low nicotine content (VLNC) cigarettes compared with adults; (2) reducing nicotine in cigarettes to 0.4 mg/g would reduce the abuse potential of cigarettes in adolescents and young adults; (3) findings to date do not support concerns that nicotine reduction leads to compensatory smoking in young smokers; and (4) if the scope of a reduced nicotine product standard were applied to all combusted tobacco products, that would likely maximize public health benefit of this policy.

A Conceptual Framework for Understanding Multiple Tobacco Product Use and the Impact of Regulatory Action

INTRODUCTION

Over 35% of the adult tobacco-using population regularly use more than one tobacco product. Although rates of tobacco use in the United States have declined over the last decade, rates of multiple tobacco product (MTP) have either remained stable (among adults) or increased (among youth).

METHODS

In this paper, we review the literature and propose a framework for understanding both MTP use and how regulatory actions on any single tobacco product (STP) may influence the use of other tobacco products.

RESULTS AND CONCLUSIONS

Within the framework, Product, Person, and Context/Situational factors (and their interactions) influence product cross-substitution and thus patterns of use of MTPs. In addition, we propose that Context/Situation effects specifically increase the complexity of MTP-use patterns resulting in "dynamic complementarity" in addition to substitution-like relationships between tobacco products. Experimentation with, and use of, various tobacco products results in reinforcement histories that affect which products are used, in what contexts, and by whom, which in turn has downstream impacts on toxicant exposure and health. We conclude our analysis with an examination of how regulation of STPs can have impacts on the use of other STP and MTP use and provide research questions for further examining MTP use.

IMPLICATIONS

Though rates of tobacco use have declined in the United States, over 35% of the adult tobacco-using population regularly uses more than one tobacco product. This paper provides a framework for understanding MTP use and how regulatory actions on any STP may influence the use of other tobacco products. We conclude our analysis by providing research questions for further examining MTP use.

Smoking abstinence effects on emotion dysregulation in adult cigarette smokers with and without attention-deficit/hyperactivity disorder

BACKGROUND

Cigarette smoking is robustly associated with attention-deficit/hyperactivity disorder (ADHD), but little is known about psychological mechanisms accounting for this comorbid relationship. This study examined difficulties in emotion regulation, or emotion dysregulation, among adult cigarette smokers with and without ADHD. Emotion dysregulation was predicted to be higher in an ADHD group at screening and after 24 -h smoking abstinence compared to a non-ADHD group.

METHODS

Cigarette smokers with (n = 19) and without (n = 20) ADHD completed a screening visit, baseline visit, and two experimental visits: smoking as usual (i.e., smoking satiated) and after biochemically-verified 24 -h smoking abstinence (i.e., smoking abstinent). Three emotion dysregulation rating scales (two self-report and one clinician rated) were administered at the screening visit and experimental sessions. Experimental sessions also included two emotion dysregulation behavioral tasks.

RESULTS

The ADHD group scored higher on all three rating scales at screening (p's < .001). For experimental sessions, group (ADHD, non-ADHD) x condition (smoking satiated, smoking abstinence) interactions were not significant across measures. However, group main effects emerged indicating higher emotion dysregulation in the ADHD group across all measures (p's < .001). Main effects also emerged for experimental condition, but were more mixed across emotion dysregulation measures.

CONCLUSIONS

Emotion dysregulation was higher among adult smokers with ADHD and during smoking abstinence across diagnostic groups, suggesting that this malleable psychological mechanism plays a role in smoking both for those with and without ADHD-such findings can inform treatment and prevention efforts.

What Do Smokers Want in A Smartphone-Based Cessation Application?

Background

Fueled by rapid technological advances over the past decade, there is growing interest in the use of smartphones to aid in smoking cessation. Hundreds of applications have been developed for this purpose, but little is known about how these applications are accessed and used by smokers or what features smokers believe would be most useful.

Purpose

The present study sought to understand the prevalence of smartphone ownership and patterns of use among smokers as well as the perceived utility of various smartphone application features for smoking cessation that are currently in development or already available.

Methods

Daily cigarette smokers (n = 224) reported on smartphone ownership, their patterns of smartphone usage, and perceived utility of features. Features were ranked according to perceived utility and differences in both perceived utility and general smartphone use patterns were examined as a function of demographic and smoking-related variables.

Results

Most smokers (80.4%) own a smartphone, but experience with smoking cessation applications is extremely rare (6.1%). Ownership and patterns of usage differed as a function of demographic and smoking-related variables. Overall, gain-framed features were rated as most useful, while loss-framed and interpersonal features were rated as least useful.

Conclusions

Mobile health interventions have the potential to reach a large number of smokers but are currently underutilized. Additional effort is needed to ensure parity in treatment access. Gain-framed messages may be especially useful for engaging smokers, even if other features ultimately drive treatment effects.

Implications

This study describes patterns of smartphone usage among smokers and identifies the smartphone application features smokers believe would be most useful during a quit attempt. Findings indicate which subgroups of smokers are most likely to be reached with mobile health interventions and suggests that inclusion of specific features may be helpful for engaging smokers in the smoking cessation process.

Graphic Warning Labels Affect Hypothetical Cigarette Purchasing Behavior among Smokers Living with HIV

Cigarette pack graphic warning labels (GWLs) are associated with increased knowledge of tobacco-related harms; scant research has evaluated their effects on behavior among vulnerable populations. We used a behavioral economic approach to measure the effects of GWLs and price on hypothetical cigarette purchasing behavior among HIV-positive smokers. Participants (n = 222) completed a cigarette valuation task by making hypothetical choices between GWL cigarette packs at a fixed price ($7.00) and text-only warning label cigarette packs at increasing prices ($3.50 to $14.00; $0.25 increments). More than one-quarter (28.8%) of participants paid more to avoid GWLs. The remaining participants’ purchasing decisions appear to have been driven by price: 69.8% of participants chose the cheaper pack. Across all participants, overall monetary choice value observed for GWL cigarette packs (mean = $7.75) was greater than if choice was driven exclusively by price ($7.00). Most (87.4%) preferred the text-only warning label when GWL and text-only cigarette packs were equally priced. Correlation analysis indicated GWL pack preference was associated with agreement with statements that GWLs would stop individuals from having a cigarette or facilitate thoughts about quitting. These data suggest that GWLs may influence some HIV-positive smokers in such a way that they are willing to pay more to avoid seeing GWLs.

Identifying Smoking Environments From Images of Daily Life With Deep Learning

IMPORTANCE

Environments associated with smoking increase a smoker's craving to smoke and may provoke lapses during a quit attempt. Identifying smoking risk environments from images of a smoker's daily life provides a basis for environment-based interventions.

OBJECTIVE

To apply a deep learning approach to the clinically relevant identification of smoking environments among settings that smokers encounter in daily life.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, 4902 images of smoking (n = 2457) and nonsmoking (n = 2445) locations were photographed by 169 smokers from Durham, North Carolina, and Pittsburgh, Pennsylvania, areas from 2010 to 2016. These images were used to develop a probabilistic classifier to predict the location type (smoking or nonsmoking location), thus relating objects and settings in daily environments to established smoking patterns. The classifier combines a deep convolutional neural network with an interpretable logistic regression model and was trained and evaluated via nested cross-validation with participant-wise partitions (ie, out-of-sample prediction). To contextualize model performance, images taken by 25 randomly selected participants were also classified by smoking cessation experts. As secondary validation, craving levels reported by participants when viewing unfamiliar environments were compared with the model's predictions. Data analysis was performed from September 2017 to May 2018.

MAIN OUTCOMES AND MEASURES

Classifier performance (accuracy and area under the receiver operating characteristic curve [AUC]), comparison with 4 smoking cessation experts, contribution of objects and settings to smoking environment status (standardized model coefficients), and correlation with participant-reported craving.

RESULTS

Of 169 participants, 106 (62.7%) were from Durham (53 [50.0%] female; mean [SD] age, 41.4 [12.0] years) and 63 (37.3%) were from Pittsburgh (31 [51.7%] female; mean [SD] age, 35.2 [13.8] years). A total of 4902 images were available for analysis, including 3386 from Durham (mean [SD], 31.9 [1.3] images per participant) and 1516 from Pittsburgh (mean [SD], 24.1 [0.5] images per participant). Images were evenly split between the 2 classes, with 2457 smoking images (50.1%) and 2445 nonsmoking images (49.9%). The final model discriminated smoking vs nonsmoking environments with a mean (SD) AUC of 0.840 (0.024) (accuracy [SD], 76.5% [1.6%]). A model trained only with images from Durham participants effectively classified images from Pittsburgh participants (AUC, 0.757; accuracy, 69.2%), and a model trained only with images from Pittsburgh participants effectively classified images from Durham participants (AUC, 0.821; accuracy, 75.0%), suggesting good generalizability between geographic areas. Only 1 expert's performance was a statistically significant improvement compared with the classifier (α = .05). Median self-reported craving was significantly correlated with model-predicted smoking environment status (ρ = 0.894; P = .003).

CONCLUSIONS AND RELEVANCE

In this study, features of daily environments predicted smoking vs nonsmoking status consistently across participants. The findings suggest that a deep learning approach can identify environments associated with smoking, can predict the probability that any image of daily life represents a smoking environment, and can potentially trigger environment-based interventions. This work demonstrates a framework for predicting how daily environments may influence target behaviors or symptoms that may have broad applications in mental and physical health.

Using Neuroscience to Inform Tobacco Control Policy

INTRODUCTION

Techniques employed in the field of neuroscience, such as eye tracking, electroencephalography, and functional magnetic resonance imaging, have been important in informing our understanding of the cognitive mechanisms underlying tobacco smoking. These techniques are now increasingly being used to investigate the likely impact of tobacco control policies.

AIMS AND METHODS

In this narrative review, we outline the value of these methodological approaches in answering policy-relevant tobacco control research questions, with a particular focus on their use in examining the impact of standardized cigarette packaging and health warnings. We also examine the limitations of these methodologies and provide examples of how they can be used to answer other policy-relevant questions.

RESULTS

We argue that neuroscience techniques can provide more objective evidence of the impacts of policy measures, allow investigation where it is not possible to conduct behavioral manipulations, and facilitate a deeper understanding of the cognitive mechanisms underlying the impacts of tobacco control policies such as standardized packaging, health warnings, point-of-sale displays, and mass media campaigns.

CONCLUSIONS

Rather than replacing more traditional methods of examining tobacco control measures, such as observational experiments, surveys, and questionnaires, neuroscience techniques can complement and extend these methods.

IMPLICATIONS

Neuroscience techniques facilitate objective examination of the mechanisms underlying the impacts of tobacco control measures. These techniques can therefore complement and extend other methodologies typically used in this field, such as observational experiments, surveys, and questionnaires.

The Effects of Nicotine and Tobacco Use on Brain Reward Function: Interaction With Nicotine Dependence Severity

INTRODUCTION

This study investigated the effects of nicotine/tobacco on neural activation during performance of a monetary incentive delay task.

AIMS AND METHODS

Prior to each scan, nonsmokers received nicotine or placebo nasal spray, and smokers were smoking satiated or 24-hour withdrawn. During the scan, participants made timed responses to reward-related cues and received feedback. Parameter estimates from cue- and feedback-related activation in medial prefrontal regions and the nucleus accumbens were extracted and underwent within- and between-group analyses. Smokers' nicotine dependence severity was included as a continuous predictor variable for neural activation.

RESULTS

Among smokers (n = 21), withdrawal decreased cue-related activation in the supplementary motor area and ventromedial prefrontal cortex, and the difference in activation (satiety > withdrawal) in these regions negatively correlated with nicotine dependence severity (Fagerström Test for Nicotine Dependence). Among nonsmokers (n = 22), nicotine increased the difference in nucleus accumbens activation between rewarded and nonrewarded feedback phases. Tobacco withdrawal and acute nicotine also had widespread effects on activation throughout the brain during the feedback phase.

CONCLUSIONS

Acute nicotine in nonsmokers may have increased the salience of feedback information, but produced few effects on reward-related activation overall, perhaps reflecting nicotine's modest, indirect effects on reward processing. Conversely, tobacco withdrawal decreased activation compared with satiety, and this difference between conditions correlated with nicotine dependence severity. This suggests that as smokers become more dependent on nicotine, tobacco withdrawal has a more pronounced effect on reward processing.

IMPLICATIONS

Relative to the acute effects of nicotine in nonsmokers, withdrawal from daily tobacco use had more significant effects on reward-related brain activation. This study suggests that the effects of tobacco withdrawal on reward-related brain function interact with subjects' level of nicotine dependence severity. These are potentially important sources of variability that could contribute to smoking cessation outcomes.

Longitudinal stability in cigarette smokers of urinary eicosanoid biomarkers of oxidative damage and inflammation

The urinary metabolites (Z)-7-[1R,2R,3R,5S)-3,5-dihydroxy-2-[(E,3S)-3-hydroxyoct-1-enyl]cyclopentyl]hept-5-enoic acid (8-iso-PGF2α), an F2-isoprostane and biomarker of oxidative damage, and "prostaglandin E2 metabolite" (PGE-M), a biomarker of inflammation, are elevated in cigarette smokers. However, there is little information in the literature on the longitudinal stability of these widely used biomarkers. In a large clinical trial involving 10 institutional sites, smokers were given, free of charge over a period of 20 weeks, Spectrum NRC600/601 research cigarettes containing 15.5 mg nicotine/g tobacco. All participants were instructed to smoke these cigarettes for the duration of the study. At weeks 4, 8, 12, 16, and 20, first morning urine voids were collected and analyzed for 8-iso-PGF2α and PGE-M using validated liquid chromatography-electrospray ionization-tandem mass spectrometry methods. The mean level of 8-iso-PGF2α at Week 4 was 1.34 ± 1.08 (S.D.) pmol/mg creatinine (N = 226) while that of PGE-M was 73.7 ± 113 (S.D.) pmol/mg creatinine (N = 232). The corresponding levels at Week 20 were 1.35 ± 0.93 (S.D.) pmol/mg creatinine (N = 209) for 8-iso-PGF2α and 74.2 ± 142 (S.D.) pmol/mg creatinine (N = 210) for PGE-M. There was variation in these values in the intervening weeks. The intra-class correlation coefficients (ICC) were 0.51 (95% CI, 0.45, 0.57) and 0.36 (0.30, 0.43), for 8-iso-PGF2α and PGE-M, respectively, indicating fair longitudinal stability for 8-iso-PGF2α and poorer longitudinal stability for PGE-M in cigarette smokers. Males had higher ICC values than females for both 8-iso-PGF2α and PGE-M. These results indicate that, in addition to cigarette smoking, endogenous processes of oxidative damage and inflammation influence the levels of these biomarkers over time among current smokers.

Combined Smoking Cues Enhance Reactivity and Predict Immediate Subsequent Smoking

Introduction

Cue reactivity (CR) research has reliably demonstrated robust cue-induced responding among smokers exposed to common proximal smoking cues (eg, cigarettes, lighter). More recent work demonstrates that distal stimuli, most notably the actual environments in which smoking previously occurred, can also gain associative control over craving. In the real world, proximal cues always occur within an environment; thus, a more informative test of how cues affect smokers might be to present these two cue types simultaneously.

Methods

Using a combined-cue counterbalanced CR paradigm, the present study tested the impact of proximal (smoking and neutral) + personal environment (smoking and nonsmoking places) pictorial cues, on smokers' subjective and behavioral CR; as well as the extent to which cue-induced craving predicts immediate subsequent smoking in a within-subjects design.

Results

As anticipated, the dual smoking cue combination (ProxS + EnvS) led to the greatest cue-induced craving relative to the other three cue combinations (ProxS + EnvN, ProxN + EnvS, and ProxN ± EnvN), ps < .004. Dual smoking cues also led to significantly shorter post-trial latencies to smoke, ps < .01. Overall CR difference score (post-trial craving minus baseline craving) was predictive of subsequent immediate smoking indexed by: post-trial latency to smoke [B = -2.69, SE = 9.02; t(143) = -2.98, p = .003]; total puff volume [B = 2.99, SE = 1.13; t(143) = 2.65, p = .009]; and total number of puffs [B = .053, SE = .027; t(143) = 1.95, p = .05].

Conclusions

The implications of these findings for better understanding the impact of cues on smoking behavior and cessation are discussed.

Implications

This novel cue reactivity study examined smokers' reactivity to combined proximal and distal smoking cues. Exposure to a combination of two smoking cues (proximal and environment) led to the greatest increases in cue-induced craving and smoking behavior compared to all other cue combinations. Further, the overall magnitude of cue-induced craving was found to significantly predict immediate subsequent smoking. This work provides new insight on how exposure to various cues and cue combinations directly affect smokers' craving and actual smoking behavior, as well as the relationship between those two indices of reactivity.

Longitudinal stability in cigarette smokers of urinary biomarkers of exposure to the toxicants acrylonitrile and acrolein

The urinary metabolites cyanoethyl mercapturic acid (CEMA) and 3-hydroxypropyl mercapturic acid (3-HPMA) have been widely used as biomarkers of exposure to acrylonitrile and acrolein, respectively, but there are no published data on their consistency over time in the urine of cigarette smokers. We provided, free of charge over a 20 week period, Spectrum NRC600/601 research cigarettes to cigarette smokers in the control arm of a randomized clinical trial of the reduced nicotine cigarette. Urine samples were collected at weeks 4, 8, 12, 16, and 20 and analyzed for CEMA and 3-HPMA, and total nicotine equivalents (TNE) using validated methods. Creatinine-corrected intra-class correlation coefficients for CEMA, 3-HPMA, and TNE were 0.67, 0.46, and 0.68, respectively, indicating good longitudinal consistency for CEMA, while that of 3-HPMA was fair. A strong correlation between CEMA and TNE values was observed. These data support the use of CEMA as a reliable biomarker of tobacco smoke exposure. This is the first report of the longitudinal stability of the biomarkers of acrylonitrile and acrolein exposure in smokers. The data indicate that CEMA, the biomarker of acrylonitrile exposure, is consistent over time in cigarette smokers, supporting its use. While 3-HPMA levels were less stable over time, this biomarker is nevertheless a useful monitor of human acrolein exposure because of its specificity to this toxicant.

Young adult dual combusted cigarette and e-cigarette users' anticipated responses to hypothetical e-cigarette market restrictions

Introduction: The aim of this exploratory study was to assess young adult dual e-cigarette (EC) and combusted cigarette (CC) users' anticipated responses to hypothetical market restrictions regarding key EC characteristics. Methods: Data came from 240 young adult dual EC and CC users recruited via Amazon Mechanical Turk in June 2017. Descriptive statistics were used to report sociodemographic, CC smoking, and EC use characteristics. McNemar's chi-square tests and chi-square tests were used to assess differences between groups in terms of anticipated responses to hypothetical EC market restrictions. Results: Hypothetical regulations resulted in reported intentions to reduce EC use and increase CC use; the greatest impact was found for restrictions regarding e-liquid nicotine content, followed by flavor and ability to modify EC devices. Moreover, individuals reporting use of flavored e-liquid, high nicotine content e-liquid, and customizable EC were most likely to report intentions to reduce EC use and increase CC use. Conclusions: This work provides preliminary evidence that restrictive regulations regarding key EC characteristics may increase intentions to increase CC use among young adult dual EC and CC users.

Young adult dual combusted cigarette and e-cigarette users' anticipated responses to a nicotine reduction policy and menthol ban in combusted cigarettes

BACKGROUND

The aim of the study was to assess young adult dual e-cigarette (EC) and combusted cigarette (CC) users' anticipated responses to a hypothetical very low nicotine content product standard and menthol ban in CC.

METHODS

Data came from 240 young adult (18-29 years) dual CC and EC users recruited via Amazon Mechanical Turk between June 20-22, 2017. Descriptive statistics were used to report sample characteristics. McNemar's tests were used to assess differences between product categories in terms of anticipated responses to hypothetical regulations.

RESULTS

A hypothetical very low nicotine content product standard in CC resulted in reported intentions to quit or reduce CC use and increase use of EC (p's<0.001). Hypothetical restrictions regarding the availability of menthol CC resulted in marginally significant reported intentions to increase EC use (p = 0.080). Anticipated responses to regulation were associated with baseline EC and CC use characteristics.

CONCLUSIONS

This work provides preliminary evidence of the impact that regulations regarding nicotine content and menthol in CC may have on the use of EC among young adult dual users.

Cannabinoid exposure and altered DNA methylation in rat and human sperm

Little is known about the reproductive effects of paternal cannabis exposure. We evaluated associations between cannabis or tetrahydrocannabinol (THC) exposure and altered DNA methylation in sperm from humans and rats, respectively. DNA methylation, measured by reduced representation bisulfite sequencing, differed in the sperm of human users from non-users by at least 10% at 3,979 CpG sites. Pathway analyses indicated Hippo Signaling and Pathways in Cancer as enriched with altered genes (Bonferroni p < 0.02). These same two pathways were also enriched with genes having altered methylation in sperm from THC-exposed versus vehicle-exposed rats (p < 0.01). Data validity is supported by significant correlations between THC exposure levels in humans and methylation for 177 genes, and substantial overlap in THC target genes in rat sperm (this study) and genes previously reported as having altered methylation in the brain of rat offspring born to parents both exposed to THC during adolescence. In humans, cannabis use was also associated with significantly lower sperm concentration. Findings point to possible pre-conception paternal reproductive risks associated with cannabis use.

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).

Smartphone-Based Contingency Management Intervention to Improve Pre-Exposure Prophylaxis Adherence: Pilot Trial

Background

Pre-exposure prophylaxis (PrEP) provides a strong preventative benefit to individuals at risk for HIV. While PrEP adherence is highly correlated with its efficacy, adherence rates are variable both across and within persons.

Objective

The objective of this study was to develop and pilot-test a smartphone-based intervention, known as mSMART, that targets PrEP adherence. mSMART provides contingency management in the form of monetary incentives for daily PrEP adherence based on a real-time adherence assessment using a camera-based medication event-monitoring tool as well as medication reminders, PrEP education, individualized behavioral strategies to address PrEP adherence barriers, and medication adherence feedback.

Methods

This was a 4-week open-label, phase I trial in a community sample of young men who have sex with men already on PrEP (N=10).

Results

Although adherence composite scores corresponding to PrEP biomarkers indicated that 90% (9/10) of the sample already had an acceptable baseline adherence in the protective range, by the end of the 4-week period, the scores improved for 30% (3/10) of the sample—adherence did not worsen for any participants. Participants reported mean PrEP adherence rates of 91% via daily entries in mSMART. At the end of the 4-week period, participants indicated acceptable ratings of satisfaction, usability, and willingness to recommend mSMART to others. There were no technical difficulties associated with smartphone compatibility, user misunderstandings about mSMART features that interfered with daily use, or study attrition.

Conclusions

This study is the first to apply contingency management to PrEP adherence. Findings indicated that mSMART is feasible and acceptable. Such an adherence intervention administered via a user-friendly smartphone app can allow for widespread dissemination. Future efficacy trials are needed.

Trial Registration

ClinicalTrials.gov NCT02895893; https://clinicaltrials.gov/ct2/show/NCT02895893 (Accessed by Webcite at http://www.webcitation.org/72JskjDJq)

Effect of Immediate vs Gradual Reduction in Nicotine Content of Cigarettes on Biomarkers of Smoke Exposure: A Randomized Clinical Trial

Importance

The optimal temporal approach for reducing nicotine to minimally or nonaddictive levels in all cigarettes sold in the United States has not been determined.

Objectives

To determine the effects of immediate vs gradual reduction in nicotine content to very low levels and as compared with usual nicotine level cigarettes on biomarkers of toxicant exposure.

Design, Setting, and Participants

A double-blind, randomized, parallel-design study with 2 weeks of baseline smoking and 20 weeks of intervention was conducted at 10 US sites. A volunteer sample of daily smokers with no intention to quit within 30 days was recruited between July 2014 and September 2016, with the last follow-up completed in March 2017.

Interventions

(1) Immediate reduction to 0.4 mg of nicotine per gram of tobacco cigarettes; (2) gradual reduction from 15.5 mg to 0.4 mg of nicotine per gram of tobacco cigarettes with 5 monthly dose changes; or (3) maintenance on 15.5 mg of nicotine per gram of tobacco cigarettes.

Main Outcomes and Measures

Between-group differences in 3 co-primary biomarkers of smoke toxicant exposure: breath carbon monoxide (CO), urine 3-hydroxypropylmercapturic acid (3-HPMA, metabolite of acrolein), and urine phenanthrene tetraol (PheT, indicator of polycyclic aromatic hydrocarbons) calculated as area under the concentration-time curve over the 20 weeks of intervention.

Results

Among 1250 randomized participants (mean age, 45 years; 549 women [44%]; 958 [77%] completed the trial), significantly lower levels of exposure were observed in the immediate vs gradual reduction group for CO (mean difference, -4.06 parts per million [ppm] [95% CI, -4.89 to -3.23]; P < .0055), 3-HPMA (ratio of geometric means, 0.83 [95% CI, 0.77 to 0.88]; P < .0055), and PheT (ratio of geometric means, 0.88 [95% CI, 0.83 to 0.93]; P < .0055). Significantly lower levels of exposure were observed in the immediate reduction vs control group for CO (mean difference, -3.38 [95% CI, -4.40 to -2.36]; P < .0055), 3-HPMA (ratio of geometric means, 0.81 [95% CI, 0.75 to 0.88]; P < .0055), and PheT (ratio of geometric means, 0.86 [95% CI, 0.81 to 0.92]; P < .0055). No significant differences were observed between the gradual reduction vs control groups for CO (mean difference, 0.68 [95% CI, -0.31 to 1.67]; P = .18), 3-HPMA (ratio of geometric means, 0.98 [95% CI, 0.91 to 1.06]; P = .64), and PheT (ratio of geometric means, 0.98 [95% CI, 0.92 to 1.04]; P = .52).

Conclusions and Relevance

Among smokers, immediate reduction of nicotine in cigarettes led to significantly greater decreases in biomarkers of smoke exposure across time compared with gradual reduction or a control group, with no significant differences between gradual reduction and control.

Trial Registration

clinicaltrials.gov Identifier: NCT02139930.

Adherence to Pharmacological Smoking Cessation Interventions: A Literature Review and Synthesis of Correlates and Barriers

Introduction

Efficacious pharmacological interventions for smoking cessation are available, but poor adherence to these treatments may limit these interventions overall impact. To improve adherence to smoking cessation interventions, it is first necessary to identify and understand smoker-level characteristics that drive nonadherence (ie, nonconformance with a provider's recommendation of timing, dosage, or frequency of medication-taking during the prescribed length of time).

Methods

We present a literature review of studies examining correlates of, or self-reported reasons for, nonadherence to smoking cessation pharmacotherapies. Studies were identified through PubMed-using MeSH terms, Embase-using Emtree terms, and ISI Web of Science.

Results and Conclusions

This literature review included 50 studies that examined nonpreventable (eg, sociodemographics) and preventable (eg, forgetfulness) factors associated with adherence to smoking cessation medication and suggestions for overcoming some of the identified barriers. Systematic study of this topic would be facilitated by consistent reporting of adherence and correlates thereof in the literature, development of consistent definitions of medication adherence across studies, utilization of more objective measures of adherence (eg, blood plasma levels vs. self-report) in addition to reliance on self-reported adherence.

Implications

This article provides the most comprehensive review to date on correlates of adherence to pharmacological smoking cessation interventions. Challenges and specific gaps in the literature that should be a priority for future research are discussed. Future priorities include additional research, particularly among vulnerable populations of smokers, developing standardized definitions of adherence and methods for measuring adherence, regular assessment of cessation pharmacotherapy adherence in the context of research and clinical practice, and development of novel treatments aimed at preventable barriers to medication adherence.

Predicting Smoking Events with a Time-Varying Semi-Parametric Hawkes Process Model

Health risks from cigarette smoking - the leading cause of preventable death in the United States - can be substantially reduced by quitting. Although most smokers are motivated to quit, the majority of quit attempts fail. A number of studies have explored the role of self-reported symptoms, physiologic measurements, and environmental context on smoking risk, but less work has focused on the temporal dynamics of smoking events, including daily patterns and related nicotine effects. In this work, we examine these dynamics and improve risk prediction by modeling smoking as a self-triggering process, in which previous smoking events modify current risk. Specifically, we fit smoking events self-reported by 42 smokers to a time-varying semi-parametric Hawkes process (TV-SPHP) developed for this purpose. Results show that the TV-SPHP achieves superior prediction performance compared to related and existing models, with the incorporation of time-varying predictors having greatest benefit over longer prediction windows. Moreover, the impact function illustrates previously unknown temporal dynamics of smoking, with possible connections to nicotine metabolism to be explored in future work through a randomized study design. By more effectively predicting smoking events and exploring a self-triggering component of smoking risk, this work supports development of novel or improved cessation interventions that aim to reduce death from smoking.

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

Perceived risk of developing smoking-related disease among persons living with HIV

Perceived risk of smoking is associated with smoking status, interest in quitting, cessation attempts, and quit success. Research is needed to explore risk perceptions of developing smoking-related disease among persons living with HIV (PLWH). Data came from 267 HIV-positive smokers who completed an online survey assessing perceived health risks associated with (a) generic smoking status; (b) generic non-smoking status; (c) their own personal current smoking; and (d) a hypothetical situation in which they were a non-smoker. PLWH perceived greater risk associated with their current smoking versus hypothetical personal non-smoking (p's < 0.001), and greater risks associated with generic smoking status compared with their current smoking (p's < 0.001). Being on HIV medication (β = 0.65, 95% CI = 0.17, 1.12), interest in quitting smoking (β = 0.89, 95% CI = 0.45, 1.32), and having an HIV healthcare provider who has recommended cessation (β = 1.04, 95% CI = 0.42, 1.67) were positively associated with perceived risk of developing smoking-related diseases. Findings have implications for developing targeted interventions to correct misperceptions regarding the health risks of smoking among PLWH, a population at particular risk for smoking and smoking-related morbidity and mortality.

Decline in the perceived risk of cigarette smoking between 2006 and 2015: Findings from a U.S. nationally representative sample

INTRODUCTION

Perceived risk of smoking is associated with smoking status, interest in quitting, quit attempts, and sustained quitting. Tracking and reporting of risk perceptions is integral to inform regulation and education. However, no research describes temporal changes in perceived great risk of smoking in the U.S. using nationally representative data.

METHODS

Data came from the 2006-2015 National Survey on Drug Use and Health (NSDUH). Time trends were assessed for the population overall, stratified by smoking status and by sociodemographic characteristics. Linear time trends of perceived great risk (versus other risk) were assessed using logistic regression, with survey year as the predictor.

RESULTS

Perceived great risk of smoking declined significantly among the entire population between 2006 and 2015 (73.89% versus 72.89%). Perceived great risk also decreased among all smoking statuses: daily (51.16% versus 48.19%), non-daily (64.12% versus 58.44%, former (79.57% versus 77.12%), and non-smokers (79.32% versus 77.10%). The prevalence of perceived great risk declined between 2006 and 2015 among both males and females; the rate of decline was more rapid among females (aOR = 0.98, 95% CI = 0.97, 0.98 versus aOR = 0.99, 95% CI = 0.98, 0.99). Older age, African American and Hispanic race/ethnicity, educational attainment, and non-daily, former, and never smoking statuses were positively associated with perceived great risk of smoking.

DISCUSSION

Perceived risk of smoking has declined over a 10-year period in the U.S. Declines in perceived risk indicate the need for innovative interventions to reinforce the harms associated with smoking. Differential rates of decline among males and females indicate the need for sex-specific interventions.

ADHD, Smoking Withdrawal, and Inhibitory Control: Results of a Neuroimaging Study with Methylphenidate Challenge

Smoking withdrawal negatively impacts inhibitory control, and these effects are greater for smokers with preexisting attention problems, such as attention deficit/hyperactivity disorder (ADHD). The current study preliminarily evaluated changes in inhibitory control-related behavior and brain activation during smoking withdrawal among smokers with ADHD. Moreover, we investigated the role of catecholamine transmission in these changes by examining the effects of 40 mg methylphenidate (MPH) administration. Adult daily smokers with (n=17) and without (n=20) ADHD completed fMRI scanning under each of three conditions: (a) smoking as usual+placebo; (b) 24 h smoking abstinence+placebo and (c) 24 h smoking abstinence+MPH. Scan order was randomized and counterbalanced. Participants completed a modified Go/No-Go task to assess both sustained and transient inhibitory control. Voxelwise analysis of task-related BOLD signal revealed a significant group-by-abstinence interaction in occipital/parietal cortex during sustained inhibition, with greater abstinence-induced decreases in activation observed among ADHD smokers compared with non-ADHD smokers. Changes in behavioral performance during abstinence were associated with changes in activation in regions of occipital and parietal cortex and bilateral insula during sustained inhibition in both groups. MPH administration improved behavioral performance and increased sustained inhibitory control-related activation for both groups. During transient inhibition, MPH increased prefrontal activation for both groups and increased striatal activation only among ADHD smokers. These preliminary findings suggest that abstinence-induced changes in catecholamine transmission in visual attention areas (eg, occipital and superior parietal cortex) may be associated with inhibitory control deficits and contribute to smoking vulnerability among individuals with ADHD.

Perceptual Characterization of the Macronutrient Picture System (MaPS) for Food Image fMRI

Food image fMRI paradigms are used widely for investigating the neural basis of ingestive behavior. However, these paradigms have not been validated in terms of ingestive behavior constructs, engagement of food-relevant neural systems, or test-retest reliability, making the generalizability of study findings unclear. Therefore, we validated the Macronutrient Picture System (MaPS) (McClernon et al., 2013), which includes food images from the six categories represented in the Geiselman Food Preference Questionnaire (FPQ) (Geiselman et al., 1998). Twenty-five healthy young adults (n = 21 female, mean age = 20.6 ± 1.1 years, mean BMI = 22.1 ± 1.9 kg/m²) rated the MaPS images in terms of visual interest, appetitive quality, nutrition, emotional valence, liking, and frequency of consumption, and completed the FPQ. In a second study, 12 individuals (n=8 female, mean age = 25.0 ± 6.5 years, mean BMI = 28.2 ± 8.7 kg/m²) viewed MaPS and control images (vegetables and non-food) during two separate 3T BOLD fMRI scans after fasting overnight. Intuitively, high fat/high sugar (HF/HS) and high fat/high complex carbohydrate (HF/HCCHO) images achieved higher liking and appetitive ratings, and lower nutrition ratings, than low fat/low complex carbohydrate/high protein (LF/LCHO/HP) images on average. Within each food category, FPQ scores correlated strongly with MaPS image liking ratings (p < 0.001). Brain activation differences between viewing images of HF/HS and vegetables, and between HF/HCCHO and vegetables, were seen in several reward-related brain regions (e.g., putamen, insula, and medial frontal gyrus). Intra-individual, inter-scan agreement in a summary measure of brain activation differences in seven reward network regions of interest was high (ICC = 0.61), and was even higher when two distinct sets of food images with matching visual ratings were shown in the two scans (ICC = 0.74). These results suggest that the MaPS provides valid representation of food categories and reliably activates food-reward-relevant neural systems.