Tobacco Cigarette Smoking Research Articles

Evaluation of toxicity of heated tobacco products aerosol and cigarette smoke to BEAS-2B cells based on 3D biomimetic chip model

It is still a controversial topic about evaluating whether heated tobacco products (HTP) really reduce harm, which involves the choice of an experimental model. Here, a three-dimensional (3D) biomimetic chip model was used to evaluate the toxicity of aerosols came from HTP and smoke produced by cigarettes (Cig). Based on cell-related experiments, we found that the toxicity of Cig smoke extract diluted four times was also much higher than that of undiluted HTP, showing higher oxidative stress response and cause mitochondrial dysfunction. Meanwhile, both tobacco products all affect the tricarboxylic acid cycle (TCA), which is manifested by a significant decrease in the mRNA expression of TCA key rate-limiting enzymes. Summarily, 3D Biomimetic chip technology can be used as an ideal model to evaluate HTP. It can provide important data for tobacco risk assessment when 3D chip model was used. Our experimental results showed that HTP may be less harmful than tobacco cigarettes, but it does show significant cytotoxicity with the increase of dose. Therefore, the potential clinical effects of HTP on targeted organs such as lung should be further studied.

Determination of tobacco-specific nitrosamines in tobacco and mainstream cigarette smoke using one-step clean-up coupled with liquid chromatography- tandem mass spectrometry

A method for determining tobacco-specific nitrosamines (TSNAs) in tobacco and cigarette smoke using liquid chromatography-tandem mass spectrometry was established. The established method amended the deficiencies that exist in current mainstream methods. In this method, TSNAs in tobacco and cigarette smoke were extracted by water. The aqueous extract was then extracted by dichloromethane, and the extract could be analyzed by liquid chromatography-tandem mass spectrometry after a solvent replacement. This method was used to analyze flue-cured tobacco samples, and the response of the target compounds was about 10 times higher than that of the ammonium acetate extraction method. When analyzing cigarette smoke samples, the response strength and chromatographic peak purity of the target compounds were also significantly improved. The proposed method exhibited good linearities for both tobacco and cigarette smoke samples (r2 > 0.99). The limits of detection (LODs) for tobacco and cigarette smoke samples were 0.2–1.0 ng/g and 0.1–0.3 ng/cigarette, respectively. Additionally, this method exhibited desirable accuracy and precision. The TSNAs recovery values from tobacco and cigarette smoke samples ranged from 95.7 % to 107.7 % with inter- and intra-day relative standard deviations (RSDs) of less than 7.4 %. This method is simple, effective, and has wide adaptability. It is a useful upgrade to the existing methods for analyzing TSNAs in tobacco and cigarette smoke.

Respiratory health effects of e-cigarette substitution for tobacco cigarettes: a systematic review

BackgroundE-cigarettes (electronic nicotine delivery system, ENDS) have been presented as a harm reduction strategy for people who smoke tobacco cigarettes but who cannot achieve abstinence, or for those who wish to continue to enjoy nicotine and the habit of smoking. What are the health effects of the substitution of ENDS for tobacco cigarettes? This systematic review evaluates the evidence of human clinical tests on the respiratory effects of ENDS use in participants who smoke tobacco cigarettes.MethodsA registered and published protocol was developed conforming to PRISMA 2020 and AMSTAR2 standards. The literature search was conducted in PubMed, Scopus, and the CENTRAL Cochrane Library and updated to May 2022. Three supplementary searches and a grey literature search were performed. Studies were evaluated with the JBI quality tools and the Oxford Catalogue of Bias. Due to the heterogeneity (diversity) of the studies, a narrative data synthesis was performed on the test findings plus three sub-group analyses.ResultsThe review consists of sixteen studies and twenty publications. Spirometry tests comprised the majority of the data. In total, 66 respiratory test measurements were reported, out of which 43 (65%) were not significant. Statistically significant findings were mixed, with 9 tests showing improvements and 14 measuring declines, none of which was clinically relevant. Ten studies were rated at a high risk of bias, and six had some concerns primarily due to inadequate research designs and the conduct of the studies. Reporting bias was documented in thirteen studies.ConclusionsMost of the studies showed no difference in respiratory parameters. This indicates that ENDS substitution for smoking likely does not result in additional harm to respiratory health. Due to the low quality of the studies, confidence in the conclusions is rated as low. Robust studies with a longer duration and sufficient power are required to validate any potential benefits or possible harms of ENDS substitution.Registration PROSPERO #CRD42021239094, International Registered Report Identifier (IRRID): DERR1-10.2196/29084.

Use of tobacco cigarettes, e-cigarettes, and shishas among children and adolescents: Results of the 'Präventionsradar' from 2016 to 2023

To measure trends in the use of various smoking products among children and adolescents from 2016 to 2023. The data is based on seven waves of the "Präventionsradar", a school-based epidemiological study in grades 5 to 10. The primary endpoints of the study were the lifetime and monthly prevalence of the use of tobacco cigarettes, e-cigarettes, shisha and the use of at least two of these smoking products (combined use). Prevalence estimates are based on logistic regression models. The analysis was based on 94,127 questionnaires. The sex ratio was balanced (49% female), mean age was 13 years (SD=1.8). In 2022/2023, the lifetime prevalence of smoking tobacco cigarettes was 18.8% (95% CI 18.1-19.5), of e-cigarettes 23.5% (95% CI 22.8-24.3), of shisha 14.0% (95% CI 13.4-14.7) and combined use 19.0% (95% CI 18.3-19.7). The monthly prevalence of smoking tobacco cigarettes was 5.9% (95% CI 5.5-6.4), of e-cigarettes 7.0% (95% CI 6.5-7.4), of shisha 3.2% (95% CI 2.8-3.5) and combined use 4.8% (95% CI 4.4-5.2). The following trends in lifetime prevalence have emerged since 2016: tobacco cigarettes (-3.0 percentage points), e-cigarettes (+1.8 percentage points), shisha (-9.2 percentage points), combined use (-2.7 percentage points). In the years of the COVID-19 pandemic, youth smoking decreased and rose again post-COVID with the exception of shisha. The use of smoking products in adolescence occurs frequently. Over the observational period, a trend reversal towards e-cigarettes as the most popular product among children and young people is most likely. In addition, the combined use of several smoking products has become a common pattern of consumption. Consistent preventive measures are required in order to achieve the goal of a smoke-free society in 2040.

Aqueous extracts from tobacco cigarette smoke reversibly inhibit isolated soluble guanylyl cyclase in vitro

Aqueous extracts from tobacco cigarette smoke reversibly inhibit isolated soluble guanylyl cyclase in vitro

Comparing cigarette-cue attentional bias between people with HIV/AIDS and people with opioid use disorder who smoke

ABSTRACT Background: Special populations like people living with HIV/AIDS (PLWHA) and people with opioid use disorder (OUD) smoke tobacco cigarettes at rates three to four times greater than the general population. Patients with tobacco use disorder exhibit attentional bias (AB) for cigarette cues. Eye tracking can quantify this bias by measuring fixation time (FT) on cigarette and matched neutral cues, to calculate an AB score. Although previous studies have measured this bias in people who smoke without any other comorbid conditions, no study, to our knowledge, has measured or compared this bias in special populations. Methods: We performed exploratory analyses on eye tracking data collected in two separate randomized clinical trials (RCTs) (NCT05049460, NCT05295953). We compared FT and cigarette-cue AB score (measured by subtracting FT on neutral cues from FT on cigarette cues) between PLWHA and people with OUD who smoke, using a visual probe task and Tobii Pro Fusion eye tracker. We used two cigarette cue types, one encompassing people smoking cigarettes and the other consisting of cigarette paraphernalia. We used two cue presentation times, 1000 and 2000 milliseconds (ms). Results: Cues of people smoking cigarettes elicited greater AB than cues of cigarette paraphernalia across both subject groups when cues were presented for 2000 ms, but not 1000 ms. PLWHA who smoke exhibited greater AB for cues of people smoking cigarettes than cigarette paraphernalia when presented for 2000 ms compared to people with OUD who smoke. Conclusion: We use cigarette-cue AB to quantify craving and cigarette consumption in two populations smoking at elevated rates. The addition of social cues potentiates cigarette cue AB, based on cue type and stimulus presentation time. Understanding the neurobiology of this relationship can help design novel smoking cessation treatments that target AB and prevent relapse in these populations with suboptimal response to smoking cessation treatments. Trial registration: Clinical trials that provided the data for post hoc analyses are NCT05049460 and NCT05295953.

E-Cigarette Use and the Cessation of Tobacco Cigarette Smoking: Protocol for an Umbrella Review.

Electronic nicotine delivery systems (ENDS), commonly called e-cigarettes, have been examined in clinical studies for their effects on tobacco smoking cessation. In the past 2 years, a dozen or more systematic reviews on ENDS and cigarette smoking cessation have been published that present differing conclusions and recommendations on the use of ENDS. Our umbrella review aims to synthesize the findings from current systematic reviews to investigate the quit rates and the percentage of participants abstinent from cigarette smoking using ENDS. Additionally, we will examine the quit rates with ENDS in comparison to other established cessation treatments. The search will retrieve systematic reviews that include both clinical trials and experimental studies on the use of ENDS for smoking cessation. We will also include nonrandomized cohort studies that track ENDS use and the subsequent abstinence from smoking. Databases searches will be conducted in Embase, Scopus, PubMed, and 7 additional registries. Secondary searches will include reference checking, citation chasing, and consultations with topic experts. Two reviewers will perform a title and abstract exclusion followed by a full-paper inclusion process. Data extraction will be conducted by 1 reviewer and completely checked by a second reviewer. Each systematic review will be assessed by 2 reviewers for methodological quality using AMSTAR2 (A Measurement Tool to Assess Systematic Reviews, version 2) and for reporting bias using categories from the Centre for Evidence-Based Medicine's Catalogue of Bias. Unreported discrepancies between the protocol and the published review will be identified. The umbrella review started on March 1, 2023. At the time of publication, the study selection was being conducted and the pilot testing of the data extraction and bias assessment forms were in progress. The review is expected to be completed by December 31, 2023, followed by the submission of the review for journal publication. A second-order meta-analysis will calculate the range and average of quit rates for ENDS. A vote counting of the direction of effect, based on quit rates, will be used to present the relative effectiveness of ENDS for smoking cessation compared to other cessation treatments (including no treatment). A citation matrix will list primary studies with their bias ratings from all the systematic reviews. The effect of overlapping studies between the systematic reviews will be calculated using the corrected coverage area analysis. A sensitivity analysis will examine the impact of the intensity of cessation treatment on quit rates. Depending on the availability of data, subgroup analyses will be conducted based on participants' gender, age, prior quit attempts, and nicotine dependence. The strength or weakness of the evidence synthesis will be assessed using a stratification of evidence technique. Reporting bias will be presented with a tabulation of bias indicators. Publication bias will be assessed. The use of ENDS for smoking cessation is a highly controversial subject. Through an exhaustive synthesis of the available data, we will present the quit rates of cigarette smoking cessation obtained with ENDS and how they compare to quit rates obtained from other established cessation treatments. The critical quality and bias assessment of the systematic reviews will indicate the most reliable sources to inform treatment considerations and policy development. PROSPERO CRD42023406165; https://tinyurl.com/4ekzpbrj. PRR1-10.2196/47711.

Evaluation of the Effects of e-Cigarette Aerosol Extracts and Tobacco Cigarette Smoke Extracts on RAW264.7 Cells.

With the advancement of society, electronic cigarettes (e-cigarettes) have gained popularity among a growing number of individuals. While numerous toxicological studies have suggested that e-cigarettes are a safer alternative to traditional cigarettes, there is also a body of literature presenting contrasting findings. This in vitro study aimed to compare the effects of e-cigarettes and tobacco cigarettes (t-cigarettes) on RAW264.7 cells by using four e-cigarette aerosol extracts (ECA) and cigarette smoking extracts (CS) containing different nicotine concentrations. The results revealed that low concentration of nicotine in CS as well as in ECA with grape, watermelon, and cola flavors could promote cell viability. Conversely, high nicotine concentration in CS and ECA with four flavors decreased cell viability. Furthermore, our study demonstrated that CS significantly reduced the phagocytic capability of RAW264.7 cells and increased the levels of inflammatory cytokines (IL-6, TNF-α, and IL-1β) and reactive oxygen species (ROS) compared to ECA. Overall, our findings indicate all four e-cigarettes induced less cytotoxicity to RAW264.7 cells and might be safer than t-cigarettes.

Endothelial-derived extracellular vesicles associated with electronic cigarette use impair cerebral microvascular cell function.

The aim of this study was to determine the effect of circulating endothelial cell-derived microvesicles (EMVs) isolated from e-cigarette users on human cerebral microvascular endothelial cells (hCMECs) nitric oxide (NO) and endothelin (ET)-1 production and tissue-type plasminogen activator (t-PA) release. Circulating EMVs (CD144-PE) were isolated (flow cytometry) from 27 young adults (19-25 yr): 10 nonsmokers (6 M/4 F), 10 e-cigarette users (6 M/4 F), and 7 tobacco cigarette smokers (4 M/3 F). hCMECs were cultured and treated with isolated EMVs for 24 h. EMVs from e-cigarette users and cigarette smokers induced significantly higher expression of p-eNOS (Thr495; 28.4 ± 4.6 vs. 29.1 ± 2.8 vs. 22.9 ± 3.8 AU), Big ET-1 (138.8 ± 19.0 vs. 141.7 ± 19.1 vs. 90.3 ± 18.8 AU) and endothelin converting enzyme (107.6 ± 10.1 and 113.5 ± 11.8 vs. 86.5 ± 13.2 AU), and significantly lower expression of p-eNOS (Ser1177; 7.4 ± 1.7 vs. 6.5 ± 0.5 vs. 9.7 ± 1.6 AU) in hCMECs than EMVs from nonsmokers. NO production was significantly lower and ET-1 production was significantly higher in hCMECs treated with EMVs from e-cigarette (5.7 ± 0.8 µmol/L; 33.1 ± 2.9 pg/mL) and cigarette smokers (6.3 ± 0.7 µmol/L; 32.1 ± 3.9 pg/mL) than EMVs from nonsmokers (7.6 ± 1.2 µmol/L; 27.9 ± 3.1 pg/mL). t-PA release in response to thrombin was significantly lower in hCMECs treated with EMVs from e-cigarette users (from 38.8 ± 6.3 to 37.4 ± 8.3 pg/mL) and cigarette smokers (31.5 ± 5.5 to 34.6 ± 8.4 pg/mL) than EMVs from nonsmokers (38.9 ± 4.3 to 48.4 ± 7.9 pg/mL). There were no significant differences in NO, ET-1, or t-PA protein expression or production in hCMECs treated with EMVs from e-cigarette users and smokers. Circulating EMVs associated with e-cigarette use adversely affects brain microvascular endothelial cells and may contribute to reported cerebrovascular dysfunction with e-cigarette use.NEW & NOTEWORTHY In the present study, we determined the effect of circulating endothelial cell-derived microvesicles (EMVs) isolated from e-cigarette users on human cerebral microvascular endothelial cells (hCMECs) nitric oxide (NO) and endothelin (ET)-1 production and tissue-type plasminogen activator (t-PA) release. EMVs from e-cigarette users reduced brain microvascular endothelial cell NO production, enhanced ET-1 production, and impaired endothelial t-PA release. EMVs are a potential mediating factor in the increased risk of stroke associated with e-cigarette use.

Diverse e-cigarette regulations in the Asia Pacific: A health economic perspective.

Diverse e-cigarette regulations in the Asia Pacific: A health economic perspective.

Impact of waterpipe and tobacco cigarette smoking on global DNA methylation and nuclear proteins genes transcription in spermatozoa: a comparative investigation

Background Waterpipe smoking is harmful and dangerous, and it is a growing threat to public health. Objectives This study was performed to evaluate the influence of waterpipe smoking on global DNA methylation, DNA fragmentation, and protamine deficiency in spermatozoa compared to cigarette heavy smokers and nonsmokers, and to determine whether the transcription levels of spermatozoa nuclear proteins genes ‘PRM1, PRM2, and H2BFWT’ in waterpipe smokers are different compared to cigarette heavy smokers and nonsmokers. Methods A total of 900 semen samples were collected from males with a mean age of 32.5 ± 6.3 years (300 waterpipe smokers, 300 cigarette heavy smokers, and 300 nonsmokers). The nucleic acids were isolated from purified spermatozoa, and then the global DNA methylation and transcription levels of the PRM1, PRM2, and H2BFWT genes were assessed using ELISA and qPCR, respectively. Results A significant increase was found in the level of global DNA methylation (8.6 ± 0.6 ng/μl vs. 7.1 ± 0.6 ng/μl and 4.7 ± 0.6 ng/μl, p < 0.001), protamine deficiency (72.8 ± 15.3 vs. 51.7 ± 19.2 and 15.3 ± 5.9%, p < 0.001), and DNA fragmentation (73.4 ± 13.4 vs. 50.5 ± 18.9 and 9.3 ± 4.3%, p < 0.001) in waterpipe smokers compared to cigarette heavy smokers and nonsmokers. A significant increase was shown in the transcription levels of PRM1, PRM2, and H2BFWT genes in waterpipe smokers compared to cigarette heavy smokers and nonsmokers (p < 0.001). A down-regulation was found in the transcription level of these genes in different smoker groups compared to nonsmokers (<0.001). Conclusion This study suggests that waterpipe smoking is more harmful than cigarette smoking on semen parameters, global DNA methylation, and transcription of nuclear protein genes.

The associations between cigarette smoking behavior and the use of heated tobacco products among Arab cigarette smokers: Findings from Saudi Arabia, Egypt, Kuwait, and Yemen

As the availability of tobacco forms has evolved, emerging products known as heated tobacco products (HTPs) are increasingly being consumed worldwide and are claimed to be less harmful than tobacco cigarette smoking. To date, it is unknown whether Arab cigarette smokers are using or susceptible to HTPs. Therefore, this study aimed to assess the association between cigarette smoking behavior and the use of and susceptibility to HTPs in the Eastern Mediterranean region. Arab cigarette smokers (n = 628) from Saudi Arabia, Egypt, Kuwait, and Yemen were recruited using a convenience sampling technique. A cross-sectional survey comprised questions related to sociodemographic characteristics, cigarette smoking behavior characteristics (quitting attempts and desire to quit cigarette smoking, nicotine dependence, and consideration of switching to nicotine products with reduced health risks), and awareness of, use of, and susceptibility to use of HTPs. Descriptive and logistic regression models were used for analysis. The participants indicated a high frequency of past quitting attempts and a desire to quit smoking cigarettes. They were also considering switching to a nicotine product with reduced health risks. However, their awareness of HTPs was relatively low (24.2%), and the proportion of participants who had ever used HTPs or were currently using them was quite low as well (10.7% and 5.0%, respectively). A history of quit attempts was associated with more likely lifetime use of HTPs (adjusted odds ratio [AOR] = 2.63, 95% confidence interval [CI] [1.21–5.71]). Nicotine-dependent cigarette smokers were more likely to be susceptible to HTP use (AOR = 1.12, 95% CI [1.01–1.24]). Moreover, those who would consider switching to a product that provided nicotine and could reduce health risks by 99% were more likely to be susceptible to using HTPs (AOR = 2.17, 95% CI [1.05–4.51]). Awareness of HTPs is relatively low among Arab cigarette smokers. Attempts to quit cigarette smoking, nicotine dependence, and the consideration of switching to a product that delivers nicotine with reduced health risks were significantly associated with using HTPs. The findings of this study provide potential for evidence-based treatment for smokers and will help prevent the use of tobacco industry tactics in marketing HTPs.

Comparison of the effects of electronic cigarette vapours and tobacco smoke extracts on human neutrophilsin vitro

Electronic cigarettes (ECs) are electronic aerosol delivery systems composed of nicotine and various chemicals, which are widely used to facilitate smoking cessation. Although ECs are considered safer than cigarettes, they do, however, contain chemical toxicants, some of which may interact with cells of the host's innate immune system of which neutrophils constitute a key component. The current study was designed to compare the effects of aqueous EC aerosol extracts (ECEs; with or without nicotine) with those of cigarette smoke extract (CSE) on neutrophil and platelet reactivity in vitro. Neutrophil reactivity is characterised by the generation of reactive oxygen species (ROS), degranulation (elastase release) and the release of extracellular DNA (neutrophil extracellular trap (NET) formation: NETosis), which were measured using chemiluminescence, spectrophotometric and microscopic procedures, respectively. Platelet reactivity was measured according to the magnitude of upregulated expression of the adhesion molecule CD62P on activated cells using a flow cytometric procedure. Exposure of neutrophils to either ECEs or CSE caused a significant inhibition of ROS generation and elastase release by N-formyl-l-methionyl-l-leucyl-l-phenylalanine (1 µM)-activated neutrophils. Pre-treatment of neutrophils with CSE also resulted in a marked attenuation of phorbol 12-myristate 13-acetate (6.25 nM)-mediated release of extracellular DNA, which was unaffected by the ECEs. Similarly, CSE, but not the ECEs, inhibited the expression of CD62P by platelets activated with ADP (100 µM). These observations suggest that ECE aerosols may inhibit some of the immuno-protective activities of neutrophils such as ROS production and elastase release by activated cells, the effect of which was not enhanced by inclusion of nicotine. The inhibitory effects of CSE were significantly more pronounced than those of ECEs, especially so for suppression of NET formation and platelet activation. If operative in vivo, these harmful immunosuppressive effects of ECEs may compromise intrinsic pulmonary antimicrobial defence mechanisms, albeit less so than cigarette smoke.

WITHDRAWN: Evaluation of the effects of e-cigarette aerosol extracts and tobacco cigarette smoke extracts on human gingival epithelial cells

Smoking increases the risk of a number of diseases, including cardiovascular, oral and lung diseases. E-cigarettes are gaining popularity among young people as an alternative to cigarettes, but there is debate over whether they are less harmful to the mouth than e-cigarettes. In this study, human gingival epithelial cells (HGECs) were treated with four commercially available e-cigarette aerosol condensates (ECAC) or commercially available generic cigarette smoke condensates (CSC) with different nicotine concentrations. Cell viability was determined by MTT assay. Cell apoptosis was observed by acridine orange (AO) and Hoechst33258 staining. The levels of type I collagen, matrix metalloproteinase (MMP-1, MMP-3), cyclooxygenase 2 and inflammatory factors were detected by ELISA and RT-PCR. Finally, ROS levels were analyzed by ROS staining. The different effects of CSC and ECAC on HGECs were compared. The results showed that higher nicotine concentration of CS significantly reduced the activity of HGECs. By contrast, all ECAC had no significant effect. The levels of matrix metalloproteinase, COX-2, and inflammatory factors were higher in HGECs treated with CSC than those treated with ECAC. In contrast, the level of type I collagen was higher in HGECs treated with ECAC than those treated with CSC. In conclusion, all four flavors of e-cigarettes were less toxic to HGE cells than tobacco, but further clinical studies are needed to determine whether e-cigarettes are less harmful to oral health than conventional cigarettes.

Epidemiology and prevalence of tobacco use in Tehran; a report from the recruitment phase of Tehran cohort study

IntroductionTobacco use is a major health concern worldwide, especially in low/middle-income countries. We aimed to assess the prevalence of cigarette smoking, waterpipe, and pipe use in Tehran, Iran.MethodsWe used data from 8272 participants of the Tehran Cohort Study recruitment phase. Tobacco use was defined as a positive answer to using cigarettes, waterpipes, or pipes. Participants who did not report tobacco use during the interview but had a previous smoking history were categorized as former users. Age- and sex-weighted prevalence rates were calculated based on the national census data, and characteristics of current and former tobacco users were analyzed.ResultsAge- and sex-weighted prevalence of current tobacco users, cigarette smokers, waterpipe, and pipe users in Tehran was 19.8%, 14.9%, 6.1%, and 0.5%, respectively. Current tobacco use was higher in younger individuals (35–45 years: 23.4% vs. ≥ 75 years: 10.4%, P < 0.001) and men compared to women (32.9% vs. 7.7% P < 0.001). The prevalence of tobacco use increased with more years of education (> 12 years: 19.3% vs. illiterate: 9.7%, P < 0.001), lower body mass index (< 20 kg/m2: 31.3% vs. ≥ 35 kg/m2: 13.8%, P < 0.001), higher physical activity (high: 23.0% vs. low: 16.4%, P < 0.001), opium (user: 66.6% vs. non-user: 16.5%, P < 0.001), and alcohol use (drinker: 57.5% vs. non-drinker: 15.4%, P < 0.001). Waterpipe users were younger (46.1 vs. 53.2 years) and had a narrower gender gap in prevalence than cigarette smokers (male/female ratio in waterpipe users: 2.39 vs. cigarette smokers: 5.47). Opium (OR = 5.557, P < 0.001) and alcohol consumption (OR = 4.737, P < 0.001) were strongly associated with tobacco use. Hypertension was negatively associated with tobacco use (OR = 0.774, P = 0.005).ConclusionThe concerning prevalence of tobacco use in Tehran and its large gender gap for cigarette and waterpipe use warrant tailored preventive policies.

Estimation of the global number of vapers: 82 million worldwide in 2021

PurposeNicotine is consumed by one in five of the global adult population, mostly by smoking tobacco cigarettes. Modern electronic cigarettes came onto the market from around 2007 and have considerable potential to improve population health by displacing tobacco smoking. The purpose of this study is to map the use of e-cigarettes, but this is difficult due to absence of data sources for many countries.Design/methodology/approachThe global number of vapers was estimated to be 68 million in 2020. New data in 2021 offered an opportunity to update that estimate. The method of assumed similarity was used for countries with missing data. The average prevalence of vaping was calculated for each World Health Organization region, World Bank income classification group and the legal status of e-cigarettes in each country. The number of vapers was calculated for the adult population. The estimate was refined by adjusting for changes in market value size and the actual year of surveys.FindingsPopulation prevalence data on e-cigarette used were available for 48 countries. We estimate that there were 82 million vapers worldwide in 2021: 9.2 million in the Eastern Mediterranean region; 5.6 million in the African region; 20.1 million in the European region; 16.8 million in the Americas; 16.0 million in the Western Pacific region; and 14.3 million in South-East Asia.Originality/valueGlobal, regional and national estimates of the numbers of vapers are important indicators of trends in nicotine use, and monitoring the uptake of vaping is important to inform international and national policy.

Electronic cigarettes prolong ventricular repolarization in people who smoke tobacco cigarettes: implications for harm reduction.

Electronic cigarettes are often used for smoking cessation as a harm reduction strategy, but studies comparing risks of electronic cigarettes (ECs) and tobacco cigarettes (TCs) are scarce. Ventricular repolarization in people who smoke TCs is abnormal. Baseline repolarization was compared among nonusers (people who do not use TCs or ECs) and people who use ECs or TCs. The acute effects of ECs and TCs on metrics of ventricular repolarization were then compared in people who chronically smoke. A total of 110 participants (59 female), including 35 people (21 females) in the TC cohort, 34 people (17 females) in the EC cohort, and 41 people (21 females) in the nonuser cohort, were included. None of the primary outcomes, Tpeak-end (Tp-e), Tp-e/QT, and Tp-e/QTc, were different among the three cohorts at supine baseline, even when adjusted for sex. When compared with the control exposure standing after acutely using the EC but not the TC, significantly prolonged all three primary indices of ventricular repolarization in people who smoke TCs. The major new finding in this study is that in people who smoke TCs, using an EC compared with a TC significantly prolongs ventricular repolarization. Furthermore, in our subgroup analysis by sex, this adverse effect on repolarization is found only in male, not female, smokers. In summary, chronic TC smoking is the most prevalent, modifiable risk factor for cardiovascular death, including sudden cardiac death. If used for smoking cessation, ECs should only be used in the short term since they too carry their own risks; this risk appears to be greatest in males compared with females who smoke.NEW & NOTEWORTHY The major new finding in this study is that in people who smoke tobacco cigarettes, using an electronic cigarette but not a tobacco cigarette acutely and significantly prolongs several metrics of ventricular repolarization, including Tpeak-Tend, Tpeak-Tend/QT, and Tpeak-Tend/QTc. Furthermore, in our subgroup analysis by sex, this adverse effect on repolarization is found only in male, not female, smokers.

Dosimetry in the lungs of α-particles (210Po) and β-particles (210Pb) present in the tobacco smoke of conventional cigarettes and heated tobacco products

Tobacco products contain radioactive 210Pb and 210Po which can be transferred from the filler to the mainstream smoke. When inhaled, they can contribute to the radioactive dose to the lungs and are suspected to significantly contribute to lung cancer from smoking. Currently, no data are available on the radioactive risk of the heated tobacco products (HTP). However, due to the relatively high heat involved in some of these devices, there are concerns about the volatility of polonium particles.Here we used data on the 210Po and 210Pb content in tobacco smoke along with biokinetic and dosimetric models to compute the effective dose induced by conventional smoking and by using an HTP device (PMI IQOS system). Results show that conventional smoking of one pack per day induces a dose to the lung of about 0.3 mSv/year. This dose decreases by a factor of ten (0.03 mSv/year) for the IQOS system. However, this dose reduction is not obtained by specific countermeasures but by the fact that the IQOS system heats only 15% of the tobacco filler to the target temperature of 330 °C. When heated homogeneously to 300 °C, both conventional and Heets (IQOS) cigarettes release about 80% of the 210Po from the tobacco, leading to similar doses to lungs.

Longitudinal transitions in initiation, cessation, and relapse of cigarette smoking and e-cigarette use among US youth and adults: Validation of a microsimulation model.

Estimates of initiation, cessation, and relapse rates of tobacco cigarette smoking and e-cigarette use can facilitate projections of longer-term impact of their use. We aimed to derive transition rates and apply them to validate a microsimulation model of tobacco that newly incorporated e-cigarettes. We fit a Markov multi-state model (MMSM) for participants in Waves 1-4.5 of the Population Assessment of Tobacco and Health (PATH) longitudinal study. The MMSM had nine cigarette smoking and e-cigarette use states (current/former/never use of each), 27 transitions, two sex categories, and four age categories (youth: 12-17y; adults: 18-24y/25-44y/≥45y). We estimated transition hazard rates, including initiation, cessation, and relapse. We then validated the Simulation of Tobacco and Nicotine Outcomes and Policy (STOP) microsimulation model, by: (a) using transition hazard rates derived from PATH Waves 1-4.5 as inputs, and (b) comparing STOP-projected prevalence of smoking and e-cigarette use at 12 and 24 months to empirical data from PATH Waves 3 and 4. We compared the goodness-of-fit of validations with "static relapse" and "time-variant relapse," wherein relapse rates did not or did depend on abstinence duration. Per the MMSM, youth smoking and e-cigarette use was generally more volatile (lower probability of maintaining the same e-cigarette use status over time) than that of adults. Root-mean-squared error (RMSE) for STOP-projected versus empirical prevalence of smoking and e-cigarette use was <0.7% for both static and time-variant relapse simulations, with similar goodness-of-fit (static relapse: RMSE 0.69%, CI 0.38-0.99%; time-variant relapse: RMSE 0.65%, CI 0.42-0.87%). PATH empirical estimates of prevalence of smoking and e-cigarette use were mostly within the margins of error estimated by both simulations. A microsimulation model incorporating smoking and e-cigarette use transition rates from a MMSM accurately projected downstream prevalence of product use. The microsimulation model structure and parameters provide a foundation for estimating the behavioral and clinical impact of tobacco and e-cigarette policies.

Tobacco smoking and vascular biology and function: evidence from human studies

Tobacco cigarette smoking is among the most complex and least understood health risk factors. A deeper insight into the pathophysiological actions of smoking exposure is of special importance as smoking is a major cause of chronic non-communicable diseases, in particular of cardiovascular disease as well as risk factors such as atherosclerosis and arterial hypertension. It is well known that smoking exerts its negative effects on cardiovascular health through various interdependent pathophysiological actions including hemodynamic and autonomic alterations, oxidative stress, inflammation, endothelial dysfunction, thrombosis, and hyperlipidemia. Importantly, impaired vascular endothelial function is acknowledged as an early key event in the initiation and progression of smoking-induced atherosclerosis. Increasing evidence from human studies indicates that cigarette smoke exposure associates with a pathological state of the vascular endothelium mainly characterized by reduced vascular nitric oxide bioavailability due to increased vascular superoxide production. In the present overview, we provide compact evidence on the effects of tobacco cigarette smoke exposure on vascular biology and function in humans centered on main drivers of adverse cardiovascular effects including endothelial dysfunction, inflammation, and oxidative stress.