Anxiety sensitivity in relation to smoking dependence motives among Latinx persons who smoke.

Hispanic/Latinx (hereafter Latinx) persons are an established tobacco disparities population in the United States (US). Past work has suggested that individual differences in anxiety sensitivity, or the fear of arousal-based sensations, is one important cognitive construct for smoking maintenance and relapse among Latinx persons who smoke. However, previous research has not examined if anxiety sensitivity is associated with motivational facets of smoking dependence among this tobacco disparities population. In the current study, anxiety sensitivity was explored in terms of smoking motives for primary, secondary, and overall cigarette dependence. Participants included 336 English-speaking Latinx adults in the US who smoked cigarettes daily (Mage = 35.53, SD = 8.65, 37.3% Female). Results indicated that anxiety sensitivity was statistically significantly and positively related to higher primary and secondary dependence motives and marginally statistically significant to cigarette dependence; findings were evident after adjusting for numerous theoretically relevant variables (e.g., depression). Overall, the current study is the first to document linkages between anxiety sensitivity and numerous motivational bases of tobacco dependence among Latinx persons who smoke from the US.

A Novel mHealth App for Smokers Living With HIV Who Are Ambivalent About Quitting Smoking: Formative Research and Randomized Feasibility Study.

BACKGROUND: More people who smoke and are living with HIV now die from tobacco-related diseases than HIV itself. Most people are ambivalent about quitting smoking and want to quit someday but not yet. Scalable, effective interventions are needed to motivate and support smoking cessation among people ambivalent about quitting smoking (PAQS) who are living with HIV. OBJECTIVE: This study aims to develop an app-based intervention for PAQS who are living with HIV and assess its feasibility, acceptability, and potential impact. Results of this study will inform plans for future research and development. METHODS: In phase 1, PAQS living with HIV (n=8) participated in user-centered design interviews to inform the final intervention app design and recruitment plan for a subsequent randomized pilot study. In phase 2, PAQS living with HIV were randomized to either a standard care control app or a similar experimental app with additional content tailored for PAQS and those with HIV. Participants were followed for 3 months. Feasibility focused on recruitment, retention, and participants' willingness to install the app. The study was not powered for statistical significance. Indices of acceptability (satisfaction and use) and impact (smoking behavior change and treatment uptake) were assessed via automated data and self-report among those who installed and used the app (n=19). RESULTS: Recruitment for both study phases was a challenge, particularly via web-based and social media platforms. Enrollment success was greater among people living with HIV recruited from a health care provider and research registry. Once enrolled, retention for the phase 2 randomized study was good; 74% (14/19) of the participants completed the 3-month follow-up. Phase 1 findings suggested that PAQS living with HIV were receptive to using an app-based intervention to help them decide whether, when, and how to stop smoking, despite not being ready to quit smoking. Phase 2 findings further supported this conclusion based on feedback from people who agreed to use an app, but group differences were observed. Indices of acceptability favored the experimental arm, including a descriptively higher mean number of sessions and utilization badges. Similarly, indices of potential impact were descriptively higher in the experimental arm (proportion reducing smoking, making a quit attempt, or calling free tobacco quitline). No participants in either arm quit smoking at the 3-month follow-up. CONCLUSIONS: On the basis of this formative work, PAQS living with HIV may be receptive to using a mobile health-based app intervention to help them decide whether, when, or how to stop using tobacco. Indices of acceptability and impact indicate that additional research and development are warranted. TRIAL REGISTRATION: ClinicalTrials.gov NCT05339659; https://clinicaltrials.gov/study/NCT05339659.

The potential of new nicotine and tobacco products as tools for people who smoke to quit combustible cigarettes - a systematic review of common practices and guidance towards a robust study protocol to measure cessation efficacy.

New types of nicotine and tobacco products like electronic cigarettes (ECs), heated tobacco products or nicotine pouches have been discussed as less harmful alternatives to combustible cigarettes and other toxic forms of tobacco products. Their harm reduction potential lay in the efficient transition away from smoking to those new products. Numerous studies addressing the cessation efficacy of ECs have been published with contradictory outcomes. Yet, a comprehensive Cochrane review concluded with high certainty on the cessation efficacy of ECs. This prompted us to perform a review to identify weaknesses in common study designs and to summarize best practices for the study design on the potential of new nicotine products as cessation aids. 120 articles retrieved from Medline were found to be eligible. Most of the studies in the field were interventional trials while observational studies played a minor role in the evaluation of smoking cessation. Efficacy was predominantly assessed for ECs in 77% of the reports while heated tobacco (17%) and non-combustible products (11%) were less frequently investigated up to now. Measures to determine the efficacy were questionnaire-based assessments as well as use documentation/prevalence and abstinence rates. Studies varied largely in their duration and sample size with medians of 3 months and 156.5 participants, respectively.With the help of this review, we identified several weaknesses in the common study designs. One major limitation in longitudinal trials was the lack of compliance measures suited to verify the use status over longer time periods, relying solely on self-reports. Moreover, the motivation of the participants to quit was rarely defined and a profound familiarization period was not taken into account for the majority of the studies. To what extent such weaknesses influence the outcome of the studies was beyond the scope of this review. We encourage researchers to consider the recommendations which resulted from this review in order to determine the abuse liability and cessation efficacy of the products in a more robust manner. Finally, we like to call attention to the missing data for low- and middle-income countries which would require quitting strategies most urgently to combat the tobacco smoking epidemic.

Oral Mucosa and Saliva Alterations Related to Vape.

OBJECTIVES: Electronic nicotine delivery systems (e-cigarette, pod, and vape) are currently among the tobacco consumption of adolescents and young adults. The aim is to show oral mucosa and saliva alterations related to vape. MATERIAL AND METHODS: A vape-user patient, presenting a white plaque in the posterior region of the hard palate, underwent clinical examination, sialometry, pH evaluation, and excisional biopsy of the white lesion. Molecular changes in saliva and vape liquid were analyzed by vibrational spectroscopy. RESULTS: The histopathological analyses showed hyperparakeratosis without dysplasia. Formaldehyde, ketones, and aromatic hydrocarbon species were identified in e-cig liquid by the FTIR. CONCLUSIONS: The use of vape may be related to the development of hyperkeratotic lesions in the oral mucosa as well as significantly modify the patient's salivary patterns as the vape liquid presents carcinogenic and cytotoxic components in its composition.

Hydroponic Growth of [13C]-Labeled Tobacco for DNA Damage Studies in Cigarette Smokers.

Cigarette smoking is the acknowledged major cause of cancers of the lung and oral cavity and is an established important risk factor for multiple other cancers. DNA addition products (DNA adducts) caused by cigarette smoking are critical factors in its mechanism of carcinogenesis. However, most DNA adducts detected to date in humans cannot be specifically ascribed to smoking but rather have multiple exogenous and endogenous sources. In the study reported here, we prepared [13C]-labeled tobacco to address this problem. We report for the first time the successful growth from seeds to flowering under hydroponic conditions of highly [13C]-labeled tobacco in a controlled 13CO2 environment. The standard growth procedure with optimized conditions is described in detail. The [13C]-enrichment rate was assessed by quantifying nicotine and sugars and their [13C]-isotopologues in this tobacco using high-resolution mass spectrometry, reaching >94% in the tobacco leaves. The [13C]-labeled leaves after curing will be used to make cigarettes, allowing investigation of the specific contributions of tobacco smoke carcinogens to identified DNA adducts in smokers.

Use of disposable e-cigarettes among youth who vape in Canada, England and the United States: Repeat cross-sectional surveys, 2017-2023.

AIMS: To measure changes over time (between 2017 and 2023) in disposable e-cigarette use and popular brands among youth in Canada, England and the United States (US) who vaped. DESIGN: Nine waves of repeat cross-sectional data from the International Tobacco Control Policy Evaluation Project (ITC) Youth Tobacco and Vaping Survey. SETTING: Online surveys conducted in Canada, England and the US between 2017 and 2023. PARTICIPANTS: Youth aged 16 to 19 years who had vaped in the past 30 days (n = 19 710). MEASUREMENTS: Usual type (disposable, cartridge/pod, tank) and brand of e-cigarette used; covariates sex at birth, age, race/ethnicity, cigarette smoking status, vaping on ≥20 of the past 30 days. FINDINGS: In 2017, the majority of youth who vaped in the past 30 days reported using refillable tank e-cigarettes, whereas disposable e-cigarettes were the least commonly used product type in Canada (10.0%), England (8.6%) and the US (14.4%). Cartridge/pods overtook tank devices in Canada and the US by 2020; however, by 2023, disposables were the leading type of e-cigarette used by youth who vaped in all three countries (Canada = 58.5%; England = 83.2%; US = 67.3%). The shift to disposables occurred among all socio-demographic groups, with few differences by vaping and smoking status. The percentage of youth who vaped that reported 'no usual' brand also decreased substantially from 2017 (29% to 42%) to 2023 (11% to 17%). The rise of disposable e-cigarettes appeared to be driven primarily by individual brands in the US (Puff Bar in 2020/2021, Elf Bar in 2022/2023) and England (Elf Bar in 2022/2023). CONCLUSIONS: The e-cigarette market has evolved rapidly with notable shifts in the types of e-cigarettes used by youth who vape in Canada, England and the United States. Although the timing differed across countries, major shifts in device types appear to be driven by individual brands and were often accompanied by increases in vaping prevalence among youth.

Exploring the relationship between smoking and poor sleep quality: a cross-sectional study using NHANES.

Introduction: Sleeping disorders is a high prevalent disorder, and although previous research has suggested a link between smoking and sleep disorders, there is a lack of large-scale, nationally representative studies examining this association across multiple sleep outcomes and exploring dose-response relationships. Methods: This study used data from 30,269 participants from the NHANES database (2007-2020). Weighted logistic regression models were used to assess the associations between smoking status (non-smoker, light smoker, moderate smoker, and heavy smoker) and various sleep outcomes, including insufficient sleep duration, reported sleep problems, snoring, snorting, or stopping breathing during sleep, and daytime sleepiness. Dose-response relationships were explored using restricted cubic splines. Results: Compared to non-smokers, heavy smokers had significantly higher odds of experiencing insufficient sleep duration with OR 1.732 (95% CI 1.528-1.963, P <0.001), reported sleep problems with OR 1.990 (95% CI 1.766-2.243, P <0.001), occasional or frequent snoring with OR 1.908 (95% CI 1.164-3.128, P = 0.03), and occasional or frequent snorting or stopping breathing during sleep with OR 1.863 (95% CI 1.183-2.936, P = 0.022), while results for sometimes, often or almost always being overly sleepy during the day with OR 1.257 (95% CI 0.872-1.810, P = 0.115) are not significant. A trend of positive correlation was observed between smoking and all sleep disorder outcomes (P for trend < 0.05). Dose-response analyses revealed that the odds of these sleep outcomes increased with higher smoking levels. Conclusion: Smoking is significantly associated with various sleep disorders, and a dose-response relationship exists between smoking levels and the odds of experiencing these sleep problems. These findings underscore the importance of addressing smoking as a modifiable risk factor for poor sleep health and suggest that reducing smoking, even if complete cessation is not achieved, may have positive effects on sleep outcomes.

Inhalation of nicotine-containing electronic cigarette vapor exacerbates the features of COPD by inducing ferroptosis in ßENaC-overexpressing mice.

Introduction: Chronic obstructive pulmonary disease (COPD) is currently listed as the 3rd leading cause of death in the United States. Accumulating data shows the association between COPD occurrence and the usage of electronic nicotine delivery systems (ENDS) in patients. However, the underlying pathogenesis mechanisms of COPD have not been fully understood. Methods: In the current study, bENaC-overexpressing mice (bENaC mice) were subjected to whole-body ENDS exposure. COPD related features including emphysema, mucus accumulation, inflammation and fibrosis are examined by tissue staining, FACS analysis, cytokine measurement. Cell death and ferroptosis of alveolar epithelial cells were further evaluated by multiple assays including staining, FACS analysis and lipidomics. Results: ENDS-exposed mice displayed enhanced emphysema and mucus accumulation, suggesting that ENDS exposure promotes COPD features. ENDS exposure also increased immune cell number infiltration in bronchoalveolar lavage and levels of multiple COPD-related cytokines in the lungs, including CCL2, IL-4, IL-13, IL-10, M-CSF, and TNF-α. Moreover, we observed increased fibrosis in ENDS-exposed mice, as evidenced by elevated collagen deposition and a-SMA+ myofibroblast accumulation. By investigating possible mechanisms for how ENDS promoted COPD, we demonstrated that ENDS exposure induced cell death of alveolar epithelial cells, evidenced by TUNEL staining and Annexin V/PI FACS analysis. Furthermore, we identified that ENDS exposure caused lipid dysregulations, including TAGs (9 species) and phospholipids (34 species). As most of these lipid species are highly associated with ferroptosis, we confirmed ENDS also enhanced ferroptosis marker CD71 in both type I and type II alveolar epithelial cells. Discussion: Overall, our data revealed that ENDS exposure exacerbates features of COPD in bENaC mice including emphysema, mucus accumulation, abnormal lung inflammation, and fibrosis, which involves the effect of COPD development by inducing ferroptosis in the lung.

Distinct roles and molecular mechanisms of nicotine and benzo(a)pyrene in ferroptosis of lung adenocarcinoma and lung squamous cell carcinoma.

INTRODUCTION: The essence of ferroptosis is the accumulation of membrane lipid peroxides caused by increased iron, which disrupts the redox balance within cells and triggers cell death. Abnormal metabolism of iron significantly increases the risk of lung cancer and induces treatment resistance. However, the roles and mechanisms of smocking in ferroptosis in patients with lung cancer are still unclear. METHODS: Our study was a secondary bioinformatics analysis followed by an experimental cell culture analysis. In this study, we identified the different ferroptosis-related genes and established the signature in lung squamous cell carcinoma (LUSC) and lung adenocarcinoma (LUAD) patients with different smocking status, based on The Cancer Genome Atlas (TCGA) database. Fanyl diphosphate fanyl transferase 1 (FDFT1) in LUSC patients and solute carrier one family member 5 (SLC1A5) in LUAD patients were confirmed to be related to ferroptosis. Next, we checked the roles of two main components of smoke, nicotine, and benzo(a)pyrene (BaP), in ferroptosis of non-small-cell lung cancer (NSCLC) cells. RESULTS: We confirmed that nicotine inhibited reactive oxygen species (ROS) levels and induced glutathione peroxidase (GPX4) expression, while the opposite roles of BaP were observed in NSCLC cells. Mechanically, nicotine protected NSCLC cells from ferroptosis through upregulation of epidermal growth factor receptor (EGFR) and SLC1A5 expression. BaP-induced ferroptosis in NSCLC cells depends on FDFT1 expression. CONCLUSIONS: In this study, the ferroptosis-associated gene signature was identified in LUAD and LUSC patients with different smoking status. We confirmed nicotine-protected LUAD and LUSC cells from ferroptosis by upregulating EGFR and SLC1A5 expression. BaP-induced ferroptosis in these cells depends on FDFT1 expression.

Nicotine flux and pharmacokinetics-based considerations for early assessment of nicotine delivery systems.

In the past few years, technological advancements enabled the development of novel electronic nicotine delivery systems (ENDS). Several empirical measures such as "nicotine flux" are being proposed to evaluate the abuse liability potential of these products. We explored the applicability of nicotine flux for clinical nicotine pharmacokinetics (PK) and 52-week quit success from cigarettes for a wide range of existing nicotine delivery systems. We found that the differences in nicotine flux for various nicotine delivery systems are not related to changes in PK, as nicotine flux does not capture key physiological properties such as nicotine absorption rate. Further, the 52-week quit success and abuse liability potential of nicotine nasal sprays (high nicotine flux product), and nicotine inhalers (nicotine flux similar to ENDS) are low, suggesting that nicotine flux is a poor metric for the assessment of nicotine delivery systems. PK indices are more dependable for characterizing nicotine delivery systems, and a nicotine plasma C max T max > 1 could improve 52-week quit success from cigarettes. However, a single metric may be inadequate to fully assess the abuse liability potential of nicotine delivery systems and needs to be further studied. A combination of in vitro and in silico approaches could potentially address the factors influencing the inhaled aerosol dosimetry and resulting PK of nicotine to provide early insights for ENDS assessments. Further research is required to understand nicotine dosimetry and PK for ad libitum product use, and abuse liability indicators of nicotine delivery systems. This commentary is intended to (1) highlight the need to think beyond a single empirical metric such as nicotine flux, (2) suggest potential PK-based metrics, (3) suggest the use of in vitro and in silico tools to obtain early insights into inhaled aerosol dosimetry for ENDS, and (4) emphasize the importance of considering comprehensive clinical pharmacology outcomes to evaluate nicotine delivery systems.

Interrelated involvement of the endocannabinoid/endovanilloid (TRPV1) systems and epigenetic processes in anxiety- and working memory impairment-related behavioural effects of nicotine as a stressor.

The addictive use of nicotine contained in tobacco is associated with stressor-like emotional and cognitive effects such as anxiety and working memory impairment, and the involvement of epigenetic mechanisms such as histone acetylation has recently been reported. Although the precise nature of behavioural plasticity remains unclear, both anxiogenic- and working memory impairment-like effects were observed in the present experimental model of mice treated with repeated subcutaneous nicotine and/or immobilization stress, and these effects were commonly attenuated by the histone deacetylase (HDAC) inhibitors that induce histone acetylation. Such HDAC inhibitor-induced resilience was mimicked by ligands for the endocannabinoid (ECB) system, a neurotransmitter system that is closely associated with nicotine-induced addiction-related behaviours: the anxiogenic-like effects were mitigated by the cannabinoid type 1 (CB1) agonist arachidonylcyclopropylamide (ACPA), whereas the working memory impairment-like effects were mitigated by the CB1 antagonist SR 141716A. Moreover, the effects of the HDAC inhibitors were also mimicked by ligands for the endovanilloid (transient receptor potential vanilloid 1 [TRPV1]) system, a system that shares common characteristics with the ECB system: the anxiogenic-like effects were mitigated by the TRPV1 antagonist capsazepine, whereas the working memory impairment-like effects were mitigated by the TRPV1 agonist olvanil. Notably, the HDAC inhibitor-induced anxiolytic-like effects were attenuated by SR 141716A, which were further counteracted by capsazepine, whereas the working memory improvement-like effects were attenuated by capsazepine, which were further counteracted by SR 141716A. These results suggest the contribution of interrelated control of the ECB/TRPV1 systems and epigenetic processes such as histone acetylation to novel therapeutic approaches.

Hypersensitivity of the nicotinic acetylcholine receptor subunit (CHRNA2L9'S/L9'S) in female adolescent mice produces deficits in nicotine-induced facilitation of hippocampal-dependent learning and memory.

Adolescence is characterized by a critical period of maturation and growth, during which regions of the brain are vulnerable to long-lasting cognitive disturbances. Adolescent exposure to nicotine can lead to deleterious neurological and psychological outcomes. Moreover, the nicotinic acetylcholine receptor (nAChR) has been shown to play a functionally distinct role in the development of the adolescent brain. CHRNA2 encodes for the α2 subunit of nicotinic acetylcholine receptors associated with CA1 oriens lacunosum moleculare GABAergic interneurons and is associated with learning and memory. Previously, we found that adolescent male hypersensitive CHRNA2L9'S/L9' mice had impairments in learning and memory during a pre-exposure-dependent contextual fear conditioning task that could be rescued by low-dose nicotine exposure. In this study, we assessed learning and memory in female adolescent hypersensitive CHRNA2L9'S/L9' mice exposed to saline or a subthreshold dose of nicotine using a hippocampus-dependent task of pre-exposure-dependent contextual fear conditioning. We found that nicotine-treated wild-type female mice had significantly greater improvements in learning and memory than both saline-treated wild-type mice and nicotine-treated CHRNA2L9'S/L9' female mice. Thus, hyperexcitability of CHRNA2 in female adolescent mice ablated the nicotine-mediated potentiation of learning and memory seen in wild-types. Our results indicate that nicotine exposure during adolescence mediates sexually dimorphic patterns of learning and memory, with wild-type female adolescents being more susceptible to the effects of sub-threshold nicotine exposure. To understand the mechanism underlying sexually dimorphic behavior between hyperexcitable CHRNA2 mice, it is critical that further research be conducted.

Suppression by central adenosine A3 receptors of the cholinergic defense against cardiovascular aberrations of sepsis: role of PI3K/MAPKs/NFκB signaling.

Introduction: Despite the established role of peripheral adenosine receptors in sepsis-induced organ dysfunction, little or no data is available on the interaction of central adenosine receptors with sepsis. The current study tested the hypothesis that central adenosine A3 receptors (A3ARs) modulate the cardiovascular aberrations and neuroinflammation triggered by sepsis and their counteraction by the cholinergic antiinflammatory pathway. Methods: Sepsis was induced by cecal ligation and puncture (CLP) in rats pre-instrumented with femoral and intracisternal (i.c.) catheters for hemodynamic monitoring and central drug administration, respectively. Results: The CLP-induced hypotension, reduction in overall heart rate variability (HRV) and sympathovagal imbalance towards parasympathetic predominance were abolished by i.v. nicotine (100 µg/kg) or i.c. VUF5574 (A3AR antagonist, 2 µg/rat). In addition, the selective A3AR agonist, 3-iodobenzyl-5'-N-methylcarboxamidoadenosine IB-MECA, 4 µg/rat, i.c.) exaggerated the hypotension and cardiac autonomic dysfunction induced by sepsis and opposed the favorable nicotine actions against these septic manifestations. Immunohistochemically, IB-MECA abolished the nicotine-mediated downregulation of NFκB and NOX2 expression in rostral ventrolateral medullary areas (RVLM) of brainstem of septic rats. The inhibitory actions of IB-MECA on nicotine responses disappeared after i.c. administration of PD98059 (MAPK-ERK inhibitor), SP600125 (MAPK-JNK inhibitor) or wortmannin (PI3K inhibitor). Moreover, infliximab (TNFα inhibitor) eliminated the IB-MECA-induced rises in RVLM-NFκB expression and falls in HRV, but not blood pressure. Conclusion: Central PI3K/MAPKs pathway mediates the A3AR counteraction of cholinergic defenses against cardiovascular and neuroinflammatory aberrations in sepsis.

Pilot randomised controlled trial of a culturally aligned smoking cessation app for American Indian persons.

OBJECTIVE: To pilot test QuitGuide for Natives, a culturally aligned version of the National Cancer Institute's QuitGuide smartphone app for smoking cessation. METHODS: This randomised controlled trial was conducted remotely during 2022-2023. American Indian adults who smoked and resided in the Midwest (n=115) were randomised to QuitGuide for Natives or the general audience QuitGuide smartphone-based intervention. Group differences in feasibility (times the app was initiated), usability, acceptability ('How likely would you be to recommend the app to a friend?'), fit of app with culture and preliminary efficacy (24-hour quit attempts, cotinine-confirmed self-reported 7-day abstinence) outcomes were examined. RESULTS: QuitGuide for Natives versus the general audience QuitGuide did not differ in the number of times the app was opened (adjusted incidence rate ratio 0.94 (95% CI 0.63 to 1.40); p=0.743) nor in usability score (adjusted mean difference (aMD) 0.73 (95% CI: -5.00 to 6.46); p=0.801) or likeliness of recommending the app to a friend (aMD 0.62 (95% CI -0.02 to 1.27); p=0.058). Differences were observed for all cultural fit outcomes such as 'The app fits my American Indian culture (aMD 0.75 (95% CI 0.35 to 1.16); p<0.001). QuitGuide for Natives versus the general audience QuitGuide resulted in an average of 6.6 vs 5.1 24-hour quit attempts (p=0.349) and cotinine-confirmed 7-day abstinence was achieved by 6.9% vs 3.5% (p=0.679). CONCLUSIONS: Acceptability, cultural fit and preliminary efficacy findings are encouraging and will inform future, larger-scale evaluation of culturally aligned digital smoking cessation resources for American Indian adults.

Nicotine exacerbates exertional heat strain in trained men: A randomized, placebo-controlled, double-blind study.

To determine if using nicotine exacerbates exertional heat strain through an increased metabolic heat production (Hprod) or decreased skin blood flow (SkBF), ten nicotine-naïve trained males (37±12 y; VO2peak: 66±10 ml·min-1·kg-1) completed four trials at 20°C and 30°C following overnight transdermal nicotine (7mg·24h-1) and placebo use in a crossover, double-blind design. They cycled for 60 min (55% VO2peak) followed by a time-trial (~75% VO2peak) during which measures of gastro-intestinal (Tgi) and mean weighted skin ( sk) temperatures, SkBF, Hprod, and mean arterial pressure (MAP) were made. The difference in ∆Tgi between nicotine and placebo trials was greater during 30°C (0.4±0.5°C) than 20°C (0.1±0.7°C), with sk higher during nicotine than placebo trials (0.5±0.5°C, p=0.02). SkBF became progressively lower during nicotine than placebo trials (p=0.01) and progressively higher during 30°C than 20°C trials (p<0.01); MAP increased from baseline (p<0.01) and remained elevated in all trials. The difference in Hprod between 30°C and 20°C trials was lower during nicotine than placebo (p=0.01) and became progressively higher during 30°C than 20°C trials with exercise duration (p=0.03). Mean power output during the time-trial was lower during 30°C than 20°C trials (24±25 W, p=0.02), and although no effect of nicotine was observed (p>0.59) two participants (20%) were unable to complete their 30°C nicotine trials as one reached the ethical limit for Tgi (40.0°C) whilst the other withdrew due to "nausea and chills" (Tgi=39.7°C). These results demonstrate that nicotine use increases thermal strain and risk of exertional heat exhaustion by reducing SkBF.

Tobacco and Nicotine Product Use Transitions by Race and Ethnicity: Results from a Latent Transition Analysis Using Data from the Truth Longitudinal Cohort (2020-2022).

OBJECTIVE: To examine use and frequency patterns across e-cigarettes, cigarettes, and little cigars, cigars, and cigarillos (LCCs) over time and determine whether patterns differ by race and ethnicity. METHODS: Data was obtained from the Truth Longitudinal Cohort of youth and young adults between September 2020 and June 2022. Latent class and transition analyses were used to classify participants (N = 4448) into subgroups, based on frequency of tobacco product use in the past 30 days, and to estimate the probability of use pattern transitions by race and ethnicity, adjusted for the effects of gender, financial situation, parental education, household tobacco use, and sensation seeking. RESULTS: Four latent classes were identified: former/noncurrent users, predominantly frequent to daily (FTD) e-cigarette users, predominantly FTD e-cigarette and LCC users, and predominantly FTD cigarette with polytobacco users. Use trajectories differed by race and ethnicity. A lower proportion of those who identified as non-Hispanic Black (60.0%) remained e-cigarette and LCC users, relative to those who identified as non-Hispanic White (86.0%), Hispanic or Latino (86.0%), and another race and ethnicity (79.0%). A lower proportion of those who identified as Hispanic or Latino (54.0%) and another race and ethnicity (59.9%) remained cigarette with polytobacco users, relative to those who identified as non-Hispanic White (76.0%) and non-Hispanic Black (72.0%). A greater proportion of non-Hispanic Black respondents transitioned from e-cigarette and LCC user to former/noncurrent user (40.0%) and polytobacco user to e-cigarette and LCC user (11.0%), relative to other racial/ethnic groups. CONCLUSION: More research is needed to determine why tobacco use trajectories differ by race and ethnicity. Such research will be important in informing comprehensive approaches that promote evidence-based prevention policies and programs.

Attentional Bias, Pupillometry, and Spontaneous Blink Rate: Eye Characteristic Assessment Within a Translatable Nicotine Cue Virtual Reality Paradigm.

Background: Incentive salience processes are important for the development and maintenance of addiction. Eye characteristics such as gaze fixation time, pupil diameter, and spontaneous eyeblink rate (EBR) are theorized to reflect incentive salience and may serve as useful biomarkers. However, conventional cue exposure paradigms have limitations that may impede accurate assessment of these markers. Objective: This study sought to evaluate the validity of these eye-tracking metrics as indicators of incentive salience within a virtual reality (VR) environment replicating real-world situations of nicotine and tobacco product (NTP) use. Methods: NTP users from the community were recruited and grouped by NTP use patterns: nondaily (n=33) and daily (n=75) use. Participants underwent the NTP cue VR paradigm and completed measures of nicotine craving, NTP use history, and VR-related assessments. Eye-gaze fixation time (attentional bias) and pupillometry in response to NTP versus control cues and EBR during the active and neutral VR scenes were recorded and analyzed using ANOVA and analysis of covariance models. Results: Greater subjective craving, as measured by the Tobacco Craving Questionnaire-Short Form, following active versus neutral scenes was observed (F1,106=47.95; P<.001). Greater mean eye-gaze fixation time (F1,106=48.34; P<.001) and pupil diameter (F1,102=5.99; P=.02) in response to NTP versus control cues were also detected. Evidence of NTP use group effects was observed in fixation time and pupillometry analyses, as well as correlations between these metrics, NTP use history, and nicotine craving. No significant associations were observed with EBR. Conclusions: This study provides additional evidence for attentional bias, as measured via eye-gaze fixation time, and pupillometry as useful biomarkers of incentive salience, and partially supports theories suggesting that incentive salience diminishes as nicotine dependence severity increases.