Development of Opioid Use Disorder After Breast Reconstruction: Effects of Nicotine Exposure.

INTRODUCTION: After undergoing breast reconstructive surgery, patients are typically prescribed opioids. Smoking tobacco increases rate of opioid metabolism and is associated with development of opioid use disorder (OUD). The aim of this study was to determine whether patients who smoke have an increased risk of OUD after breast reconstructive surgery. Given that OUD is a known risk factor for injection drug use and intravenous drug use increases risk of acquiring blood-borne diseases including human immunodeficiency virus (HIV) and hepatitis, the secondary aim was to determine if these patients are also at increased risk of acquiring these communicable diseases associated with OUD. METHODS: A retrospective analysis was conducted using TriNetX, a multi-institutional deidentified database. Individuals included underwent a breast reconstructive surgery and received postoperative opioid treatment. The exposed group included patients who smoke. The control group did not smoke. Risk of developing OUD, hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV from 12 to 36 months after surgery was compared between groups. Patients with preexisting OUD or associated diseases were excluded. Cohorts were matched to control for confounding factors including age, sex, race, mental health history, and concomitant substance use. RESULTS: There were 8648 patients included in the analysis. After matching, 4324 patients comprised the exposure group, and 4324 patients remained in the control group. Preoperative smoking was significantly associated with increased risk of OUD at 12, 24, and 36 months after breast reconstruction (36 months: odds ratio [OR], 2.722; confidence interval [CI], 2.268-6.375). Smoking was also associated with increased risk of HIV and HCV at all time points after surgery (36 months HIV: OR, 2.614; CI, 1.977-3.458; 36 months HCV: OR, 3.718; CI, 2.268-6.375) and increased risk of HBV beginning at 24 months after surgery (36 months HBV: OR, 2.722; CI, 1.502-4.935). CONCLUSIONS: Individuals who smoke have an increased risk of developing OUD, HIV, HCV, and HBV after breast reconstructive surgery. This risk persists for at least 3 years after surgery. Additional research and clinical interventions focusing on early identification of OUD, prevention efforts, and harm reduction strategies for patients who smoke or have nicotine dependence undergoing breast reconstruction are warranted.

[The role of ROS/JNK/caspase 3 axis in apoptosis induction by menthol-favored electronic cigarette liquid in human periodontal ligament stem cells].

PURPOSE: To explore the cytotoxic effect of a menthol-favored E-liquid on human periodontal ligament stem cells (hPDLSCs), as well as the underlying mechanism of electronic cigarette (E-cig)-induced cell apoptosis. METHODS: PDLSCs were isolated and cultured from periodontal ligament tissues of healthy premolars extracted for orthodontic reasons. Cells in passage 3 were used to detect the surface markers of stem cells by flow cytometry. Then the cells were exposed to different doses of menthol-favored E-liquid (at 59 mg/L nicotine concentration) in the culture median (the final nicotine concentrations were 0.1 µg/mL, 1.0 µg/mL, 10 µg/mL, 50 µg/mL, 0.1 mg/mL, 0.2 mg/mL and 0.5 mg/mL, respectively) for different period of times (24, 48 and 72 h). The cell viability was analyzed by CCK-8 assay. Cell apoptosis was evaluated by flow cytometry (7-AAD and Annexin V staining) and TUNEL assay. Reactive oxygen species (ROS) production was detected with fluorescence probe DCFH-DA by confocal microscopy and flow cytometry. The protein expression levels associated with ROS/JNK/caspase 3 axis(p-JNK, JNK, c-Jun, p-c-Jun, Bcl-2, Bax and cleaved-caspase 3) were analyzed by Western blot. Immunocytofluorescense staining was applied to evaluate the expression level of p-JNK. After addition of NAC, a ROS scavenger, and MAPK/JNK specific blocker SP600125, their effects on E-cig-induced cell apoptosis were evaluated. Statistical analysis was performed with Graph Pad 5.0 software package. RESULTS: Human PDLSCs were successfully isolated and cultured and flow cytometry assay showed the mesenchymal stem cell surface biomarkers (CD73, CD90 and CD105) were positively expressed. CCK8 assay indicated cell viability was significantly(P＜0.001) different among all concentration groups at various time points (24, 48 or 72 h), and the difference in apoptosis rate among all concentration groups was also statistically significant (P＜0.001). After exposure to E-liquid with nicotine concentration ≥50 µg/mL, cell viability was significantly reduced, and the proportion of apoptotic cells and the cellular ROS level was significantly increased in a dose-dependent manner as compared with the control group(0.0 mg/mL). Western blot assay showed E-cig exposure could promote MAPK/JNK phosphorylation in a dose-dependent and time-dependent manner. Either NAC or SP600125 could partially rescue the E-cig-induced cell apoptosis via reversing up-regulation of p-JNK and cleaved caspase 3. CONCLUSIONS: ROS/JNK/caspase 3 axis is involved in menthol-favored E-liquid-induced apoptosis of hPDLSCs.

An exploratory, randomised, crossover study to investigate the effect of nicotine on cognitive function in healthy adult smokers who use an electronic cigarette after a period of smoking abstinence.

BACKGROUND: As well as being associated with serious negative health outcomes, smoking has been reported to have an array of physiological and psychological effects, including effects on mood and cognitive function. Post-cessation, loss of such effects (including temporary deficits in cognitive function) have been cited as reasons for resumption of smoking. The effects of e-cigarettes and nicotine delivered by e-cigarettes on these functions have not been widely researched but may play a role in the effectiveness of e-cigarettes as a satisfactory alternative to combustible cigarettes for people who smoke, and in encouraging individuals who would otherwise continue to smoke, to transition to e-cigarettes. METHODS: The study was an exploratory, randomised, partially-blinded, single-centre, five-arm crossover trial that recruited 40 healthy male and female people who smoke. At 5 study sessions, following a 12-h period of nicotine abstinence, participants were randomly assigned to use either a combustible cigarette, an e-cigarette of three varying nicotine strengths (18 mg/mL, 12 mg/mL or 0 mg/mL respectively) or observe a no product usage session. Participants completed pre- and post-product usage assessments to examine the product usage effect on cognitive performance (using the Cambridge Neuropsychological Test Automated Battery (CANTAB)), subjective mood and smoking urges. RESULTS: A significant improvement in sustained attention task performance was observed following use of both the nicotine containing e-cigarettes and combustible cigarette compared to no product use. Additionally, there were no significant differences between the nicotine containing products, indicating that nicotine use enhanced sustained attention regardless of delivery format. Nicotine containing e-cigarette and combustible cigarette use also significantly improved overall mood of participants compared to no product use, with no significant differences observed between the nicotine containing products. Nicotine containing e-cigarette and combustible cigarette use significantly reduced smoking urges compared to no product use, though combustible cigarette use elicited the greatest reduction in smoking urges. CONCLUSIONS: Overall, the nicotine containing products improved sustained attention and mood while reducing smoking urges, with the studied e-cigarettes having comparable effects to combustible cigarettes across the assessed cognitive parameters and mood measures. These results demonstrate the potential role of e-cigarettes to provide an acceptable alternative for combustible cigarettes among people who would otherwise continue to smoke. Trial registration ISRCTN (identifier: ISRCTN35376793).

Ameliorating effects of Acanthopanax koreanum extract and components on nicotine dependence and withdrawal symptoms.

Tobacco smoking is a serious health problem in society. While smoking rates are declining, smoking remains a serious risk to national health. Currently, there are several medications available to aid in smoking cessation. However, these medications have the disadvantages of low success rates in smoking cessation and various side effects. Therefore, natural-based smoking cessation aids are being suggested as a good alternative due to their accessibility and minimal side effects. The roots and stems of Acanthopanax koreanum (AK) Nakai, a plant that is native to Jeju Island, South Korea, have traditionally been used as tonic and sedatives. Moreover, eleutheroside B and chlorogenic acid are the main components of AK stem extract. In the present study, we investigated the effect of 70% ethanol AK extract and its components on ameliorating nicotine dependence and withdrawal symptoms by using behavioural tests in mice. In addition, alterations in the dopaminergic and DRD1-EPAC-ERK-CREB pathways were observed using dopamine ELISA and western blotting using mouse brains. Our findings demonstrate that the AK extract and its components effectively mitigated the effects of nicotine treatment in behavioural tests. Furthermore, it normalized the dopamine concentration and the expression level of nicotine acetylcholine receptor α7. Additionally, it was observed that AK extract and its components led to the normalization of DRD1, ERK and CREB expression levels. These results indicate that AK extract exhibits effects in ameliorating nicotine dependence behaviour and alleviating withdrawal symptoms. Moreover, EB and CGA are considered potential marker components of AK extract.

Electronic Nicotine-Delivery Systems for Smoking Cessation.

BACKGROUND: Electronic nicotine-delivery systems - also called e-cigarettes - are used by some tobacco smokers to assist with quitting. Evidence regarding the efficacy and safety of these systems is needed. METHODS: In this open-label, controlled trial, we randomly assigned adults who were smoking at least five tobacco cigarettes per day and who wanted to set a quit date to an intervention group, which received free e-cigarettes and e-liquids, standard-of-care smoking-cessation counseling, and optional (not free) nicotine-replacement therapy, or to a control group, which received standard counseling and a voucher, which they could use for any purpose, including nicotine-replacement therapy. The primary outcome was biochemically validated, continuous abstinence from smoking at 6 months. Secondary outcomes included participant-reported abstinence from tobacco and from any nicotine (including smoking, e-cigarettes, and nicotine-replacement therapy) at 6 months, respiratory symptoms, and serious adverse events. RESULTS: A total of 1246 participants underwent randomization; 622 participants were assigned to the intervention group, and 624 to the control group. The percentage of participants with validated continuous abstinence from tobacco smoking was 28.9% in the intervention group and 16.3% in the control group (relative risk, 1.77; 95% confidence interval, 1.43 to 2.20). The percentage of participants who abstained from smoking in the 7 days before the 6-month visit was 59.6% in the intervention group and 38.5% in the control group, but the percentage who abstained from any nicotine use was 20.1% in the intervention group and 33.7% in the control group. Serious adverse events occurred in 25 participants (4.0%) in the intervention group and in 31 (5.0%) in the control group; adverse events occurred in 272 participants (43.7%) and 229 participants (36.7%), respectively. CONCLUSIONS: The addition of e-cigarettes to standard smoking-cessation counseling resulted in greater abstinence from tobacco use among smokers than smoking-cessation counseling alone. (Funded by the Swiss National Science Foundation and others; ESTxENDS ClinicalTrials.gov number, NCT03589989.).

Association between electronic nicotine product use and subsequent first episode psychosis.

Tobacco use has been established as a possible risk factor for psychosis, but the effect of electronic nicotine delivery systems (ex. nicotine vapes) has not been independently established. Using the Population Assessment of Tobacco and Health study, we found that use of electronic nicotine products was significantly associated with later first episode psychosis after controlling for substance use and other confounders, and that this relationship was only significant among the heaviest users (>20 puffs/day). Given the rapid rise in electronic nicotine products use, clinicians and public health professionals should consider potential impacts and closely monitor trends in the coming years.

Electronic Cigarette Vape Exposure Exacerbates Post-Ischemic Outcomes in Female but Not in Male Rats.

BACKGROUND: Nicotine-containing electronic cigarette (EC) vaping has become popular worldwide, and our understanding of the effects of vaping on stroke outcomes is elusive. Using a rat model of transient middle cerebral artery occlusion, the current exploratory study aims to evaluate the sex-dependent effects of EC exposure on brain energy metabolism and stroke outcomes. METHODS: Adult Sprague-Dawley rats of both sexes were randomly assigned to air/EC vapor (5% nicotine Juul pods) exposure for 16 nights, followed by randomization into 3 cohorts. The first cohort underwent exposure to air/EC preceding randomization to transient middle cerebral artery occlusion (90 minutes) or sham surgery, followed by survival for 21 days. During the survival period, rats underwent sensorimotor and Morris water maze testing. Subsequently, brains were collected for histopathology. A second cohort was exposed to air/EC after which brains were collected for unbiased metabolomics analysis. The third cohort of animals was exposed to air/EC and received transient middle cerebral artery occlusion/sham surgery, and brain tissue was collected 24 hours later for biochemical analysis. RESULTS: In females, EC significantly increased (P<0.05) infarct volumes by 94% as compared with air-exposed rats, 165±50 mm3 in EC-exposed rats, and 85±29 mm3 in air-exposed rats, respectively, while in males such a difference was not apparent. Morris water maze data showed significant deficits in spatial learning and working memory in the EC sham or transient middle cerebral artery occlusion groups compared with the respective air groups in rats of both sexes (P<0.05). Thirty-two metabolites of carbohydrate, glycolysis, tricarboxylic acid cycle, and lipid metabolism were significantly altered (P≤0.05) due to EC, 23 of which were specific for females. Steady-state protein levels of hexokinase significantly decreased (P<0.05) in EC-exposed females; however, these changes were not seen in males. CONCLUSIONS: Even brief EC exposure over 2 weeks impacts brain energy metabolism, exacerbates infarction, and worsens poststroke cognitive deficits in working memory more in female than male rats.

Estimating the health impact of nicotine exposure by dissecting the effects of nicotine versus non-nicotine constituents of tobacco smoke: A multivariable Mendelian randomisation study.

The detrimental health effects of smoking are well-known, but the impact of regular nicotine use without exposure to the other constituents of tobacco is less clear. Given the increasing daily use of alternative nicotine delivery systems, such as e-cigarettes, it is increasingly important to understand and separate the effects of nicotine use from the impact of tobacco smoke exposure. Using a multivariable Mendelian randomisation framework, we explored the direct effects of nicotine compared with the non-nicotine constituents of tobacco smoke on health outcomes (lung cancer, chronic obstructive pulmonary disease [COPD], forced expiratory volume in one second [FEV-1], forced vital capacity [FVC], coronary heart disease [CHD], and heart rate [HR]). We used Genome-Wide Association Study (GWAS) summary statistics from Buchwald and colleagues, the GWAS and Sequencing Consortium of Alcohol and Nicotine, the International Lung Cancer Consortium, and UK Biobank. Increased nicotine metabolism increased the risk of COPD, lung cancer, and lung function in the univariable analysis. However, when accounting for smoking heaviness in the multivariable analysis, we found that increased nicotine metabolite ratio (indicative of decreased nicotine exposure per cigarette smoked) decreases heart rate (b = -0.30, 95% CI -0.50 to -0.10) and lung function (b = -33.33, 95% CI -41.76 to -24.90). There was no clear evidence of an effect on the remaining outcomes. The results suggest that these smoking-related outcomes are not due to nicotine exposure but are caused by the other components of tobacco smoke; however, there are multiple potential sources of bias, and the results should be triangulated using evidence from a range of methodologies.

[Puff alert: addiction to nicotine products among young people]. / Alerte aux puffs : addiction aux produits nicotiniques chez les jeunes.

Consumption of e-cigarettes (particularly the famous "puffs") and other nicotine products has risen sharply among Swiss teenagers, and now exceeds consumption of traditional cigarettes. Yet these products are harmful to health. Nicotine is highly addictive for young people, and e-cigarette use causes significant respiratory morbidity for both active and passive users. We are just measuring the extent of the toxic effects of these products, given their recent appearance on the market, but the initial scientific evidence is extremely worrisome and calls for a rapid response. Prevention among young people is crucial, and better legislation is urgently needed.

La consommation d'e-cigarettes (notamment des fameuses « puffs ¼) et d'autres produits nicotiniques a fortement augmenté chez les adolescents suisses, dépassant désormais la consommation de cigarettes traditionnelles. Ces produits sont pourtant nocifs pour la santé. La nicotine a un très fort pouvoir addictif chez les jeunes et la consommation d'e-cigarette induit une importante morbidité respiratoire pour les consommateurs actifs mais aussi passifs. Nous mesurons à peine l'étendue des effets toxiques de ces produits vue leur apparition récente sur le marché, mais les premiers éléments scientifiques sont extrêmement préoccupants et appellent à une réaction rapide. La prévention auprès des jeunes est capitale et un meilleur encadrement législatif nécessaire.

Deep-Learning-Based Analysis Reveals a Social Behavior Deficit in Mice Exposed Prenatally to Nicotine.

Cigarette smoking during pregnancy is known to be associated with the incidence of attention-deficit/hyperactive disorder (ADHD). Recent developments in deep learning algorithms enable us to assess the behavioral phenotypes of animal models without cognitive bias during manual analysis. In this study, we established prenatal nicotine exposure (PNE) mice and evaluated their behavioral phenotypes using DeepLabCut and SimBA. We optimized the training parameters of DeepLabCut for pose estimation and succeeded in labeling a single-mouse or two-mouse model with high fidelity during free-moving behavior. We applied the trained network to analyze the behavior of the mice and found that PNE mice exhibited impulsivity and a lessened working memory, which are characteristics of ADHD. PNE mice also showed elevated anxiety and deficits in social interaction, reminiscent of autism spectrum disorder (ASD). We further examined PNE mice by evaluating adult neurogenesis in the hippocampus, which is a pathological hallmark of ASD, and demonstrated that newborn neurons were decreased, specifically in the ventral part of the hippocampus, which is reported to be related to emotional and social behaviors. These results support the hypothesis that PNE is a risk factor for comorbidity with ADHD and ASD in mice.

Comparative systematic review on the safety of e-cigarettes and conventional cigarettes.

BACKGROUND: This systematic review evaluated the health risks of electronic cigarettes (e-cigarettes) compared to traditional cigarettes. It examines various studies and research on the subject to provide a comprehensive analysis of potential health risks associated with both smoking methods. METHODS: The systematic review, incorporating searches in PubMed, Scopus, Web of Science, and the Cochrane Library up to July 2023, examines the results obtained in relevant studies, and provides a critical discussion of the results. RESULTS: E-cigarettes exhibit reduced exposure to harmful toxins compared to traditional cigarettes. CONCLUSION: However, concerns persist regarding respiratory irritation and potential health risks, especially among youth, emphasizing the need for comprehensive, long-term research and protective legislation.

Nicotine and Cardiovascular Health: When Poison is Addictive - a WHF Policy Brief.

Nicotine is universally recognized as the primary addictive substance fuelling the continued use of tobacco products, which are responsible for over 8 million deaths annually. In recent years, the popularity of newer recreational nicotine products has surged drastically in many countries, raising health and safety concerns. For decades, the tobacco industry has promoted the myth that nicotine is as harmless as caffeine. Nonetheless, evidence shows that nicotine is far from innocuous, even on its own. In fact, numerous studies have demonstrated that nicotine can harm multiple organs, including the respiratory and cardiovascular systems. Tobacco and recreational nicotine products are commercialized in various types and forms, delivering varying levels of nicotine along with other toxic compounds. These products deliver nicotine in profiles that can initiate and perpetuate addiction, especially in young populations. Notably, some electronic nicotine delivery systems (ENDS) and heated tobacco products (HTP) can deliver concentrations of nicotine that are comparable to those of traditional cigarettes. Despite being regularly advertised as such, ENDS and HTP have demonstrated limited effectiveness as tobacco cessation aids in real-world settings. Furthermore, ENDS have also been associated with an increased risk of cardiovascular disease. In contrast, nicotine replacement therapies (NRT) are proven to be safe and effective medications for tobacco cessation. NRTs are designed to release nicotine in a slow and controlled manner, thereby minimizing the potential for abuse. Moreover, the long-term safety of NRTs has been extensively studied and documented. The vast majority of tobacco and nicotine products available in the market currently contain nicotine derived from tobacco leaves. However, advancements in the chemical synthesis of nicotine have introduced an economically viable alternative source. The tobacco industry has been exploiting synthetic nicotine to circumvent existing tobacco control laws and regulations. The emergence of newer tobacco and recreational nicotine products, along with synthetic nicotine, pose a tangible threat to established tobacco control policies. Nicotine regulations need to be responsive to address these evolving challenges. As such, governments should regulate all tobacco and non-medical nicotine products through a global, comprehensive, and consistent approach in order to safeguard tobacco control progress in past decades.

Dexpanthenol exhibits antiapoptotic and anti-inflammatory effects against nicotine-induced liver damage by modulating Bax/Bcl-xL, Caspase-3/9, and Akt/NF-κB pathways.

Chronic tobacco use can lead to liver damage and inflammation due to the accumulation of various toxins in the body. This study aimed to investigate the correlation between the molecular mechanisms of nicotine-induced liver injury, the caspase cascade, and the Akt/NF-κB signaling pathway, as well as the protective effects of dexpanthenol (DEX). Male rats were subjected to intraperitoneal injections of nicotine at a concentration of 0.5 mg/kg/day and/or DEX at a concentration of 500 mg/kg/day for 8 weeks. After the treatment period, liver function tests were conducted on serum samples, and tissue samples were analyzed for protein levels of Akt, NF-κB, Bax, Bcl-xL, Caspase-3, and Caspase-9, along with histopathological changes. Additionally, assessments of oxidative stress markers and proinflammatory cytokines were carried out. Nicotine administration led to elevated levels of IL-6, IL-1ß, MDA, TOS, and oxidative stress index, accompanied by decreased TAS levels. Moreover, nicotine exposure reduced the p-Akt/Akt ratio, increased NF-κB, Bax, Caspase-3, and Caspase-9 protein levels, and decreased the antiapoptotic protein Bcl-xL levels. DEX treatment significantly mitigated these effects, restoring the parameters to levels comparable to those of the control group. Nicotine-induced liver injury resulted in oxidative stress, inflammation, and apoptosis, mediated by Bax/Bcl-xL, Caspase-3, Caspase-9, and Akt/NF-κB pathways. Conversely, DEX effectively attenuated nicotine-induced liver injury by modulating apoptosis through NF-κB, Caspase-3, Caspase-9, Bax inhibition, and Bcl-xL activation.

Electronic cigarettes for smoking cessation.

BACKGROUND: Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol by heating an e-liquid. People who smoke, healthcare providers and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review. OBJECTIVES: To examine the safety, tolerability and effectiveness of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence, in comparison to non-nicotine EC, other smoking cessation treatments and no treatment. SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group's Specialized Register to 1 February 2023, and Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 July 2023, and reference-checked and contacted study authors. SELECTION CRITERIA: We included trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention as these studies have the potential to provide further information on harms and longer-term use. Studies had to report an eligible outcome. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods for screening and data extraction. Critical outcomes were abstinence from smoking after at least six months, adverse events (AEs), and serious adverse events (SAEs). We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in pairwise and network meta-analyses (NMA). MAIN RESULTS: We included 88 completed studies (10 new to this update), representing 27,235 participants, of which 47 were randomized controlled trials (RCTs). Of the included studies, we rated ten (all but one contributing to our main comparisons) at low risk of bias overall, 58 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There is high certainty that nicotine EC increases quit rates compared to nicotine replacement therapy (NRT) (RR 1.59, 95% CI 1.29 to 1.93; I2 = 0%; 7 studies, 2544 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6 more). There is moderate-certainty evidence (limited by imprecision) that the rate of occurrence of AEs is similar between groups (RR 1.03, 95% CI 0.91 to 1.17; I2 = 0%; 5 studies, 2052 participants). SAEs were rare, and there is insufficient evidence to determine whether rates differ between groups due to very serious imprecision (RR 1.20, 95% CI 0.90 to 1.60; I2 = 32%; 6 studies, 2761 participants; low-certainty evidence). There is moderate-certainty evidence, limited by imprecision, that nicotine EC increases quit rates compared to non-nicotine EC (RR 1.46, 95% CI 1.09 to 1.96; I2 = 4%; 6 studies, 1613 participants). In absolute terms, this might lead to an additional three quitters per 100 (95% CI 1 to 7 more). There is moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 1840 participants). There is insufficient evidence to determine whether rates of SAEs differ between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 9 studies, 1412 participants; low-certainty evidence). Due to issues with risk of bias, there is low-certainty evidence that, compared to behavioural support only/no support, quit rates may be higher for participants randomized to nicotine EC (RR 1.88, 95% CI 1.56 to 2.25; I2 = 0%; 9 studies, 5024 participants). In absolute terms, this represents an additional four quitters per 100 (95% CI 2 to 5 more). There was some evidence that (non-serious) AEs may be more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low-certainty evidence; 4 studies, 765 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 0.89, 95% CI 0.59 to 1.34; I2 = 23%; 10 studies, 3263 participants; very low-certainty evidence). Results from the NMA were consistent with those from pairwise meta-analyses for all critical outcomes, and there was no indication of inconsistency within the networks. Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons, hence, evidence for these is limited, with CIs often encompassing both clinically significant harm and benefit. AUTHORS' CONCLUSIONS: There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain due to risk of bias inherent in the study design. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but the longest follow-up was two years and the number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Arterial Stiffness and Carotid Intima-Media Thickness in Children Exposed to Smokeless Tobacco in Fetal Life.

BACKGROUND: Arterial stiffening and increased intima-media thickness can be seen as early as childhood and are associated with increased risk of cardiovascular events in adult life. The authors hypothesized that exposure to prenatal smokeless tobacco (Swedish snus) without additional nicotine exposure after the breastfeeding period would be associated with increased arterial stiffness and intima-media thickening in preschool children. METHODS AND RESULTS: This was a longitudinal follow-up cohort study of children aged 5 to 6 years exposed to high doses of nicotine in utero. Women exclusively using snus and unexposed controls were enrolled in early pregnancy (gestational age range, 6-12 weeks). Exposure data were collected during and after pregnancy with questionnaires from both groups. For this study, only children of women using >48 mg nicotine per day during their entire pregnancy were included in the exposure group. Outcomes were determined in 40 healthy children (21 exposed to snus in utero). Ultrasonography of the common carotid artery was used to determine carotid intima-media thickness and calculate arterial stiffness index from the relationship between pulsatile changes in arterial diameter and arterial pressure. Children exposed to snus in fetal life had higher carotid stiffness (median 4.1 [interquartile range (IQR), 2.4-5] versus 2.9 [IQR, 2.1-3.5]; P=0.014) than tobacco-free controls. Carotid strain (relative diameter change) was lower in children exposed to snus (mean 16% [SD, 5.7%] versus 21% [SD, 6.6%]) than in controls (P=0.015). Carotid intima-media thickness did not differ significantly between children exposed to snus and controls. CONCLUSIONS: Exposure to snus during fetal life was associated with a stiffer carotid artery in preschool children.

Childhood Trauma, Emotional Awareness, and Neural Correlates of Long-Term Nicotine Smoking.

Importance: Temporal dynamic measures provide insight into the neurobiological properties of nicotine use. It is critical to determine whether brain-based measures are associated with substance use risk factors, such as childhood trauma-related emotion dysregulation. Objective: To assess temporal dynamic differences based on smoking status and examine the associations between childhood trauma, alexithymia, nicotine smoking, and default mode network (DMN) states. Design, Setting, and Participants: This cross-sectional study was conducted in the Baltimore, Maryland, area at the National Institute on Drug Abuse. Participants included individuals aged 18 to 65 years who smoked nicotine long term and matched controls with no co-occurring substance use or psychiatric disorders. Participants were enrolled from August 8, 2013, to August 9, 2022. Analysis was conducted from August 2022 to July 2023. Exposure: Long-term nicotine smoking. Main Outcomes and Measures: The main outcome was temporal dynamic differences based on smoking status. Coactivation pattern analysis was conducted based on 16-minute resting-state functional magnetic resonance imaging; total time in, persistence of, and frequency of transitions into states were evaluated. The associations between childhood trauma (Childhood Trauma Questionnaire), alexithymia (20-item Toronto Alexithymia Scale), and DMN temporal dynamics were assessed. Results: The sample included 204 participants (102 individuals who smoked nicotine and 102 control individuals) with a mean (SD) age of 37.53 (10.64) years (109 [53.4%] male). Compared with controls, individuals who smoked nicotine spent more time in the frontoinsular DMN (FI-DMN) state (mean difference, 25.63 seconds; 95% CI, 8.05-43.20 seconds; η2p = 0.04; P = .004 after Bonferroni correction). In those who smoked nicotine, greater alexithymia was associated with less time spent in the FI-DMN state (r, -0.26; 95% CI, -0.44 to -0.07; P = .007). In a moderated mediation analysis, alexithymia mediated the association between childhood trauma and time spent in the FI-DMN state only in individuals who smoked nicotine (c' = -0.24; 95% CI, -0.58 to -0.03; P = .02). Conclusions and Relevance: Compared with controls, individuals who smoked nicotine spent more time in the FI-DMN state. Among those who smoked nicotine, childhood trauma-related alexithymia was associated with less time spent in the FI-DMN state, indicating that considering trauma-related factors may reveal alternative neurobiological underpinnings of substance use. These data may aid in reconciling contradictory findings in prior literature regarding the role of FI-DMN regions in substance use.