Cluster analysis of urinary tobacco biomarkers among U.S. adults: Population Assessment of Tobacco and Health (PATH) biomarker study (2013-2014).

Tobacco use delivers nicotine, tobacco-specific nitrosamines (TSNAs), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs), which are metabolized and excreted in urine offering useful biomarkers of exposure. Previous studies compared individual toxicants across tobacco users. Based on a group of biomarkers, cluster analysis was used to define tobacco toxicant exposure profiles.

Hot Wires and Film Boiling: Another Look at Carbonyl Formation in Electronic Cigarettes.

Electronic cigarettes (ECIGs) are a class of tobacco products that emit a nicotine-containing aerosol by heating and vaporizing a liquid. Apart from initiating nicotine addiction in nonsmokers, a persistent concern about these products is that their emissions often include high levels of carbonyl species, toxicants thought to cause most noncancer pulmonary diseases in smokers. This study examined whether the phenomenon of film boiling can account for observations of high carbonyl emissions under certain operating conditions and, if so, whether film boiling theory can be invoked to predict conditions where high carbonyl emissions are likely.

Natural Course of Nicotine Dependence Among Adolescent Waterpipe and Cigarette Smokers.

Purpose: Waterpipe (WP) smoking patterns and setting can result in a unique trajectory of nicotine dependence (ND) compared with cigarette smoking. This longitudinal study compared the development of ND symptoms among adolescent WP and cigarette smokers.

Methods: A cohort of 647 eighth and ninth graders in Lebanon were followed over 5 years.

Are Urine Propylene Glycol or Vegetable Glycerin Markers of E-cigarette Use or Abstinence?

Objectives: Urine propylene glycol (PG) and vegetable glycerin (VG) were evaluated as potential markers for discriminating ECIG users from non-users and verifying ECIG abstinence.

Methods: Urine samples from 51 ECIG users (collected pre/post 12-hours ECIG abstinence), and 50 controls (who do not use nicotine/tobacco) were analyzed for urine cotinine, PG, and VG concentration.

Results: Of 42 ECIG users with pre-abstinence urine cotinine indicating nicotine use, mean (SD) urine cotinine concentration was 1053.

Might limiting liquid nicotine concentration result in more toxic electronic cigarette aerosols?

Some jurisdictions have instituted limits on electronic cigarette (ECIG) liquid nicotine concentration, in an effort to control ECIG nicotine yield, and others are considering following suit. Because ECIG nicotine yield is proportional to the product of liquid nicotine concentration (milligram per millilitre) and device power (watts) regulations that limit liquid nicotine concentration may drive users to adopt higher wattage devices to obtain a desired nicotine yield. In this study we investigated, under various hypothetical regulatory limits on ECIG liquid nicotine concentration, a scenario in which a user of a common ECIG device (SMOK TF-N2) seeks to obtain in 15 puffs the nicotine emissions equivalent to one combustible cigarette (ie, 1.

Effect of flavour manipulation on ENDS (JUUL) users' experiences, puffing behaviour and nicotine exposure among US college students.

Significance: Electronic nicotine delivery system (ENDS) use has continued to increase exponentially among young people in the USA, with unique flavours being one of the most cited reasons for use. Yet, controlled studies examining the effects of restricting flavour are lacking. This study evaluates the impact of ENDS flavour manipulation on user's puffing behaviour, subjective experience, harm perception and nicotine exposure among college-aged ENDS users.

Impact of flavors and humectants on waterpipe tobacco smoking topography, subjective effects, toxicant exposure and intentions for continued use.

Introduction: The present study examined how the lack of characterising flavours and low levels of humectants may affect users' waterpipe tobacco (WT) smoking topography, subjective effects, toxicant exposure and intentions for continued use.

Methods: 89 WT smokers completed four ad libitum smoking sessions (characterising flavor/high humectant (+F+H); characterising flavor/low humectant (+F-H); no characterising flavor/high humectant (-F+H); no characterising flavor/low humectant (-F-H)) in a randomised cross-over design. WT was commercially available; same brand but nicotine levels were not held constant.

A comparison of the electrical characteristics, liquid composition, and toxicant emissions of JUUL USA and JUUL UK e-cigarettes.

In 2018, JUUL entered the UK market, where EU regulations limit liquid nicotine concentration to 20 mg/mL, approximately one-third the level of JUUL products sold in the USA. We hypothesized that JUUL's UK product was engineered to deliver greater electrical power and boost liquid vaporization such that the net nicotine delivery rate was similar to the US version. We compared electrical characteristics, liquid composition, and aerosol emissions of JUUL devices procured in the USA and the UK.

Product Substitution After A Real-World Menthol Ban: A Cohort Study.

Objectives: The province of Ontario, Canada banned menthol in cigarettes and other tobacco products effective January 1, 2017 adding to an existing flavour ban. However, all flavoured e-cigarettes, flavoured cigars larger than 6g, and alcohol flavoured cigars without filters over 1.4g were exempted.

Differences in flavourant levels and synthetic coolant use between USA, EU and Canadian Juul products.

Background: 'Juul' is the dominant US e-cigarette brand and was recently introduced to Canada, UK, France, Germany and Italy, with several flavours available across countries. US/Canadian products are sold with 5%, 3% and 1.5% (Canada only) nicotine content, whereas European Union (EU) regulation limits nicotine content to 1.

Changes at global and site-specific DNA methylation of gene promoter induced by waterpipe smoking in blood lymphocytes and oral epithelial cells.

Cigarette tobacco smoking has been shown to cause cancer through different mechanisms that include epigenetic modulation of tumor-suppressor genes. In the present study, the association between global and gene promoter methylation and waterpipe tobacco smoking was investigated. Blood lymphocytes and oral epithelium were sampled from 150 pure waterpipe smokers and 150 never-smokers from Jordan.

The effect of genetic variations in the choline acetyltransferase gene (ChAT) on waterpipe tobacco smoking dependence.

Introduction: Waterpipe tobacco smoking (WS) is a popular form of tobacco use, globally. While the impact of genetic variations on smoking behavior has been well-investigated, few studies have examined this issue with regard to WS. In the current study, associations between choline acetyltransferase gene (ChAT) rs1917810 and rs7094248 polymorphisms and WS dependence were examined.

Effect of electronic cigarette aerosol exposure during gestation and lactation on learning and memory of adult male offspring rats.

Introduction: Electronic cigarette (ECIG) use has increased worldwide, including among pregnant and breastfeeding women. In this study, we examined the effect of ECIG aerosol exposure during gestation and lactation on learning and memory of adult male offspring rats.

Methods: Rats were exposed to either fresh air or ECIG aerosol for one hour daily during gestational period as well as days 4-21 of lactation.

Effect of e-cigarette advertisement themes on hypothetical e-cigarette purchasing in price-responsive adolescents.

Aims: To examine the effect on adolescents of exposure to different e-cigarette advertisement themes on reported likelihood of purchasing e-cigarettes in a hypothetical scenario.

Design: Between-subjects design of four randomly assigned thematic conditions derived from a content analysis of 350 e-cigarette advertisements: general, flavor- and taste-themed, people- and product use-themed or control advertisements for bottled water.

Setting: Virginia, USA.

Comparison of the cardiac effects of electronic cigarette aerosol exposure with waterpipe and combustible cigarette smoke exposure in rats.

Aims: Electronic cigarette (ECIG) has been used as an alternative to tobacco smoking as it lacks the majority of toxicants found in tobacco smoke. However, the effect of ECIG aerosol inhalation on cardiac health are not well studied. The present study aimed to compare the effects of ECIGs with that of combustible tobacco cigarette (T-Cigs) and waterpipe (WP) smoke on cardiac biomarkers of oxidative stress, inflammation, and fibrosis.

E-Cigarette or Vaping Product Use-associated Lung Injury: Developing a Research Agenda. An NIH Workshop Report.

The NHLBI convened a working group on October 23, 2019, to identify the most relevant and urgent research priorities and prevailing challenges in e-cigarette or vaping product use-associated lung injury (EVALI). Experts across multiple disciplines discussed the complexities of the EVALI outbreak, identified research priorities, and recommended strategies to address most effectively its causal factors and improve diagnosis, treatment, and prevention of this disease. Many research priorities were identified, including the need to create national and international registries of patients with EVALI, to track accurately those affected and assess outcomes.

"I cannot live without my vape": Electronic cigarette user-identified indicators of vaping dependence.

Background: Limited research has examined indicators of electronic cigarette (ECIG) dependence. Researchers have adapted ECIG dependence measures from cigarette smoking dependence measures, but few have examined unique aspects of ECIG dependence. This study used concept mapping, a mixed-methods approach to examine ECIG user-identified indicators of ECIG dependence.

Acute effects of JUUL and IQOS in cigarette smokers.

Background: JUUL is an electronic cigarette that aerosolises a nicotine-containing liquid, while IQOS heats tobacco to produce an aerosol. Both are marketed to smokers, but their effects have seldom been examined in this population.

Methods: Eighteen cigarette smokers (13 men) with no JUUL or IQOS experience completed a within-subject, laboratory study assessing nicotine delivery and subjective effects after controlled (10 puffs, ~30 s interpuff interval) and ad libitum (90 min) use of JUUL, IQOS or own-brand (OB) cigarettes.

Does the Bubbler Scrub Key Toxicants from Waterpipe Tobacco Smoke?: Measurements and Modeling of CO, NO, PAH, Nicotine, and Particulate Matter Uptake.

Waterpipe tobacco smoking is a global epidemic. A persistent perception among users is that the water bubbler filters the smoke, reducing its risk profile. The objectives of this study were to quantify the purported filtering effect by comparing toxicant yield when a waterpipe was machine smoked with and without the smoke passing through the water bubbler.

Effects of electronic cigarette heating coil resistance and liquid nicotine concentration on user nicotine delivery, heart rate, subjective effects, puff topography, and liquid consumption.

Electronic cigarette (ECIG) nicotine delivery and other effects can be influenced by device and/or liquid characteristics and user puffing behavior. One class of ECIGs includes "sub-ohm" devices that incorporate heating coils with resistance less than 1 ohm (Ω), lower than that observed in conventional devices (e.g.

A pilot study to examine the acceptability and health effects of electronic cigarettes in HIV-positive smokers.

Introduction: Some HIV-positive smokers report ambivalence about quitting. Switching to electronic cigarettes (ECs) may be a viable option to reduce the negative health effects for smokers who are unable or unwilling to quit smoking combustible cigarettes (CCs). This study examined the acceptability and health-related effects of ECs in HIV-positive smokers who were not seeking smoking cessation treatment.

Reasons for Transition From Electronic Cigarette Use to Cigarette Smoking Among Young Adult College Students.

Purpose: Longitudinal studies indicate that e-cigarette use among youth and young adults is associated with cigarette smoking initiation. The purpose of this study was to identify reasons why nonsmoking young adults transition from e-cigarette use to cigarette smoking.

Methods: The study used concept mapping (CM), a mixed-method participatory approach.