The popularity of electronic cigarettes continues to rise and as a result the variety of electronic cigarette liquids (e-liquids) continues to increase and now includes variations that contain various cannabinoids such as cannabidiol (CBD). E-liquids still lack standardization with regards to their manufacturing as regulation of nicotine containing e-liquids has recently come into effect in the United States. This has resulted in e-liquid matrices and nicotine content that vary greatly depending upon manufacturer. This study sought to look at the variation in e-liquids across a number of manufacturers. A gas chromatography-mass spectrometry (GC-MS) method was developed to identify the components of and quantify the amount of nicotine in e-liquids and to identify the components of CBD containing e-liquids. Five manufacturers of e-liquids were selected including one that produced CBD containing liquids. From each of the manufacturers, excluding the one creating CBD liquids, five flavors were selected for testing. E-liquids with reported nicotine concentrations of 0 mg/mL, 6 mg/mL and 18 mg/mL were chosen for each flavor. A total of 58 liquids were tested, as some concentrations of certain flavors were unavailable at the time of testing. Four CBD liquids were obtained from a single-manufacturer for analysis. A dilution was performed prior to analysis by GC-MS due to the viscous nature of the liquids. Analysis was performed in triplicate to identify the components of the liquids and to quantify the amount of nicotine in the nicotine containing e-liquids. Identification of the components of the e-liquids and CBD liquids, and quantitation of nicotine was accomplished using GC-MS. Some but not all of the e-liquids labeled as 0 mg/mL by their manufacturer contained detectable amounts of nicotine. E-liquids labeled as having a particular concentration of nicotine may contain more or less than that which is stated. Cannabidiol liquids may contain compounds not suitable for human consumption and may not contain CBD, even if stated otherwise by the manufacturer.

Background: Over the past ten years or so, there is a huge increase in the popularity of electronic cigarettes around the world. Some people regard e-cigarettes as a tobacco substitute and use them to help smoking abstinence and relieve nicotine withdrawal symptom. On the other hand, there are those who believe that e-cigarettes should not be promoted since safety and efficacy of these battery-operated devices are still under investigation. Hence, this project aims to evaluate the effect of using electronic cigarettes to quit smoking among the conventional smokers. Methods: This project used key words to search on PubMed, MEDLINE, The Cochrane Library, 中国知网(CNKI), EMBASE, and BBCNEWS. Eventually, a total of 111 items in PubMed, 6 in The Cochrane Library and 23 were obtained in CNKI. After the screening process, finally 11relevant papers were reviewed in this project. There were two randomized controlled trials on evaluating the effect of reducing smoking with e-cigarettes. Five surveys(Survey 1-5) analyzed users’ satisfaction and their original expectations on trying electronic cigarettes. Two proof-of-concept trials also assessed the effect of using e-cigarettes on reducing and quitting smoking. In addition, a qualitative study and a case series study provided evidence on interpreting whethere-cigarettes could help smoking abstinence. Results: Brown et al. 10conducted a RCT and showed that in an intention to treat analysis, combined ≥50% smoking reduction and complete smoking abstinence was shown in 33% (99/300) at 12 weeks and 19% (57/300) at 52 weeks. Another RCT conducted by Bullen et al. showed the continuous abstinence at 1 month was23.2%in nicotine e-cigarettes group and15.9%in nicotine patches group and 16.4%in placebo e-cigarettes group; at 3 month, the rateswere13.1%, 9.2% and 6.8%; at 6 months, the rates were 7.3%, 5.8% and 4.1%.In survey 1 (Etter), satisfaction of helping smokers quit was79%; in survey 2 (Kralikova et al.), satisfaction of helping quit was over 60%; in survey 3 (Dawkins et al. 14), participants reported their situation of smoking cessation: 38% for >1 year, 19% for 6-11 months, 43% for < 6months;in survey 4 (Etter and Bullen), 92% current smokers and 96%former smokers reported ECs were effective to reduce their smoking consumption; in survey 5 (B. Siegel et al. ), 66.8% smokers reported it helped quitting smoking. In two proof-of-concept trials, sustained quitting more than 50% including quitter accounted for 55% and 64.3%.Thequalitative study and the case series study indicated that ECs were modestly effective to reduce smoking consumption with less toxic effects. Conclusion: There is some preliminary evidence from11studiesthatelectronic cigarettes could be effective for reducing conventional smoking consumption within a short period. Because there is a lack of adequate and long-term randomized controlled trials to assess the safety and efficacy of e-cigarettes, particularly in comparison to nicotine replacement therapy, government regulations should be established to control e-cigarettes and to the claim that e-cigarettes can be used as a standard as nicotine smoking cessation aid. / published_or_final_version / Public Health / Master / Master of Public Health

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Electronic cigarettes (ECIGs) operate by heating a nicotine-containing solution resulting in an inhalable aerosol. Nicotine delivery may be affected by users’ puffing behavior (puff topography), and little is known about the puff topography of ECIG users. The purpose of this study was to examine the extent to which a mouthpiece-based topography measurement device influences the acute effects associated with ECIG use. Twenty-nine experienced ECIG users completed two sessions differing only by the presence of a mouthpiece-based topography recording device. In both sessions, participants completed one 10 puff, 30 sec inter-puff interval (IPI) ECIG-use bout and another 90 minute ad libitum bout. Acute ECIG effects (plasma nicotine concentration, heart rate [HR], and subjective effects) were largely unaffected by the presence of the topography recording device. Evaluating ECIG puff topography through clinical laboratory methodology is necessary to understand the effects of these products (including toxicant exposure) and to inform their regulation.

Little is known about how electronic cigarette (EC) users manipulate device parameters, what factors drive their use, and how non-nicotine ingredients influence the stimulus effects of EC aerosols. The ingredients propylene glycol (PG) or vegetable glycerin (VG) serve as the base for virtually all electronic cigarette liquids, and information on how they affect the using experience would provide important groundwork for the study of other ingredients. In this dissertation, results from a survey and laboratory study focused on the stimulus effects of ECs, and the influence of PG and VG, will be discussed. A total of 522 regular EC users completed a survey comprised of an electronic cigarette dependence questionnaire, questions on tobacco and electronic cigarette use, and device and liquid preferences. This was followed by a laboratory study with sixteen electronic cigarette users completing five test days (one practice and four assessment days). In the laboratory study, following one hour of nicotine deprivation, two sampling puffs from liquid formulations containing 100/0, 75/25, 50/50, 25/75, and 0/100% PG/VG concentrations were administered in random order during five assessments, each separated by 20 min. Primary outcome measures were self-reported stimulus characteristics and breakpoint on a multiple-choice procedure. Survey results indicated that ability to change device voltage, and level of resistance, was significantly associated with level of nicotine dependence, as was amount of liquid consumed, nicotine concentration, and milligrams of nicotine used per week. Participants also rated 'good taste' as the most important consideration when purchasing and using liquids, and PG was associated with undesirable effects and VG with desirable effects. Laboratory results indicated that greater VG content was associated with greater reports of visibility of the exhalant (i.e. “cloud”). Liquids with mixtures of PG or VG were associated with conventional cigarette smoking sensations and greater reductions of systolic blood pressure compared to formulations with only PG or VG. There was no significant effect of liquid formulation on the multiple-choice procedure, but puffs were rarely chosen over even the smallest monetary option ($0.05), suggesting minimal reinforcing efficacy. In conclusion, survey data indicate that a wide range device parameter settings and liquid ingredients are preferred by daily e-cigarette users, and that individuals with greater nicotine dependence favor voltage control devices, and lower resistance heating elements. Survey data also indicated that taste is a key factor for EC liquid selection, and relative concentrations of propylene glycol and vegetable glycerin may have a significant impact on the reinforcing effects of liquids. In contrast, laboratory data suggests that PG or VG do not significantly impact the abuse liability of EC liquids, though reinforcing effects of these ingredients was unclear in the laboratory study.

Use of electronic cigarettes (e-cigarettes) is rapidly growing around the world. E-cigarettes are commonly used as an alternative nicotine delivery system, and have been advocated as generating lower levels of harmful chemicals compared to conventional cigarettes. Cigarette smoke-like aerosols are generated when e-cigarettes heat e-liquids. The main components of e-cigarette liquids are propylene glycol (PG) and glycerol (GL) in a varying ratio, plus nicotine and flavor chemicals. Both PG and GL are considered safe to ingest in foods and beverages, but the toxicity of these chemicals in aerosols is unknown. Current studies of e-cigarettes have mainly focused on dehydration and oxidation products of PG and GL. In this study, the other degradation products that can be generated during the vaping process are discussed. In addition, the gas/particle partitioning of chemicals in vaping aerosols is determined. This work finds that the formation of benzene in electronic cigarettes depends on the wattage, types of coils, and devices. To simulate commerical e-cigarette liquids, mixtures containing equal parts of PG and GL by volume were made with the following added components: benzoic acid (BA), benzoic acid with nicotine (Nic), benzaldehyde (BZ), band enzaldehyde with nicotine. PG only, GL only, and PG and GL mixtures were also made for comparison. The data presented here demonstrate that more benzene is generated as the wattage of a device increases. The results also seem to support the importance of ventilation in the generation of benzene. More benzene is generated from the mixtures containing benzoic acid when using the EVOD device with a smaller vent. However, benzaldehyde yields more benzene when using the Subtank Nano device with a larger vent. Findings also indicate that more benzene is produced from GL rather than PG. This thesis also addresses the chemical formation pathways of degradation compounds found in the aerosols formed from isotopically labeled e-cigarette liquids. Mixtures of both 13C-labeled and unlabeled PG as well as GL were made. The mixtures were vaped and gas-phase samples were collected to determine which chemicals were in the gas-phase portion of the aerosols. With the use of GC/MS methods, these isotopic labeling experiments provided evidence that the majority of the benzene, acetaldehyde, 2,3-butanedione, toluene, xylene, acrolein, and furan found in e-cigarette aerosols originates from GL in the PG plus GL mixtures. It was also shown that the majority of propanal is derived from PG: while hydroxyacetone can be formed from both PG and GL. Possible mechanisms for the formation of acetaldehyde, benzene, 2,3-butanedione, toluene, and xylene formation are proposed. Last, this study investigated the gas/particle partitioning of nicotine and flavor-related chemicals in e-cigarette fluids. The gas/particle partitioning behavior of chemicals in e-cigarettes fluids is highly dependent on the chemical volatility. A total of 37 compounds were examined. The target compounds were divided into 3 groups based on their vapor pressures: high, medium, and low. Headspace gas samples were collected and analyzed to determine the concentration of a compound in equilibrium with the liquid phase. The gas and liquid concentrations were used to calculate the gas/particle partitioning constant (Kp) for each compound. In an e-cigarette aerosol, volatile compounds have smaller Kp values and tend to be found in greater proportion in the gas-phase, whereas the less volatile compounds are likely to stay in the particle phase. General agreement with theory was found for compounds with known activity coefficients in PG and GL, indicating that theory can be used to predict Kp values for other compounds.

The three research studies included in this dissertation aimed to examine the reasons for e-cigarette use among U.S. adults, and to examine the U.S. public opinion on allowing e-cigarette use where smoking is otherwise prohibited. Mixed (quantitative and qualitative) research methods were used. Data from an online survey (2012) and focus groups (2014) were analyzed. Among 307 survey respondents who had ever used e-cigarettes, the three most common reasons for e-cigarette use were curiosity (40.8%), the belief that “it helps people quit smoking” (19.1%), and perceiving e-cigarettes “less harmful than regular cigarettes” (9.3%). About 40% of U.S. adults were uncertain whether e-cigarette use should be allowed in smoke-free public areas, 37% opposed, while 23% favored allowing their use in smoke-free environments. The majority of the focus group participants have used e-cigarettes to complement regular cigarette smoking and intake nicotine where smoking is restricted. E-cigarette use was viewed to be less harmful and more convenient than smoking regular cigarettes. The findings of the three studies suggest that curiosity about e-cigarettes lead to experimentation and the convenience to use e-cigarettes in smoke-free areas lead to continual use. With impending regulation and the changing e-cigarette landscape, there is a need for continued monitoring and research on reasons for and attitudes about e-cigarette use, and on public opinion pertaining to e-cigarette use in smoke-free areas.

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No description available.

Metabolomics is the systematic analysis of low-molecular weight compounds (metabolites) within biological systems that represent molecular endpoints of gene expression and environmental exposures. A major goal of metabolomics is achieving better understanding of the pathophysiology of complex disease processes while elucidating mechanisms of action of nutrients, toxins, and/or drugs. Multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS) is a high-throughput microseparation platform that is ideal for the analysis of polar/ionic metabolites from volume-restricted biological samples. This thesis includes two major metabolomics projects using MSI-CE-MS that are aimed at contributing new advances in public health and chronic disease prevention. Chapter II presents an analysis of the metabolome from patients with phenylketonuria (PKU) — a genetic disease affecting phenylalanine (Phe) metabolism that requires lifelong dietary restriction to prevent irreversible intellectual disabilities. A targeted and nontargeted metabolomics approach using matching urine and plasma samples was conducted to confirm known markers of PKU and identify new markers associated with dietary adherence and disease progression. Along with increased excretion of Phe catabolites in urine, high plasma Phe was associated with decreased excretion of acylcarnitines and greater excretion of histidine catabolites, suggesting impaired fatty acid oxidation and micronutrient deficiencies, respectively. Overall, this may provide a strategy to objectively monitor dietary adherence beyond standard dietary records or patient recall. Chapter III investigates the impact of electronic cigarette smoke exposure on the placental metabolome as a model cell line of fetal development. Evidence of altered amino acid metabolism, in addition to changes in acylcarnitines and metabolites associated with cellular proliferation, were observed in more susceptible first trimester placental cells and were attributed to flavouring agents irrespective of nicotine dosage. This work supports the hypothesis that flavoured e-cigarette formulations pose a significant health risk in comparison to unflavoured formulations and supports the need for further risk assessment and careful regulation of these products to prevent deleterious birth outcomes in pregnant mothers. / Thesis / Master of Science (MSc)