Abstract
Introduction
Although some smokers switch to exclusive use of electronic cigarettes (e-cigarettes), others become dual users of combustible cigarettes and e-cigarettes. Little is known about ...how the onset of vaping affects the use of and dependence on combustible cigarettes or total nicotine use and dependence, which may influence health-related and cessation outcomes. Using self-report data of current combustible and e-cigarette use and retrospective recall of pre-vaping smoking in a sample of dual users, the aims of this study were (1) to compare pre- and post-vaping number of cigarettes per day and combustible cigarette dependence; (2) to compare pre- and post-vaping total nicotine use frequency (number of vaping sessions and cigarettes smoked per day), and total nicotine dependence; and (3) to examine predictors of nicotine dependence.
Methods
We used baseline data from a smoking cessation trial with 2896 dual users. Nicotine use frequency and the Heaviness of Smoking Index were used as measures of nicotine use and dependence, respectively.
Results
Participants decreased cigarettes/day from pre- (M = 19.24, SD = 9.01) to post-vaping (M = 11.15, SD = 8.02, p < .0001) and combustible cigarette dependence declined from pre- (M = 3.55, SD = 1.51) to post-vaping (M = 2.11, SD = 1.60, p < .0001). Total daily nicotine use frequency increased after initiating vaping (M = 19.25, SD = 9.01 vs. M = 29.46, SD = 8.61; p < .0001), as did total nicotine dependence (M = 3.55, SD = 1.51 vs. M = 4.68, SD = 1.38; p < .0001). Hierarchical regression analyses indicated that variables associated with greater overall nicotine dependence included: younger age, lower education, more years smoking, higher pre-vaping nicotine dependence, using e-cigarettes more days per month, more puffs per vaping session, higher e-liquid nicotine concentration, and longer vaping history.
Conclusions
Dual use leads to a reduction in the number of combustible cigarettes, but total nicotine use and dependence increases.
Implications
In dual users, a reduction in smoking following onset of vaping may offer some harm reduction via reduction in cigarette intake. However, the increase in total nicotine use and dependence could affect the ability to quit either or both products.
Aims
To identify subpopulations of dual users of combustible and electronic cigarettes using current smoking and vaping behaviors.
Design
Secondary analysis of baseline data from a randomized ...controlled trial testing a smoking cessation intervention for dual users. Finite mixture modeling of frequency, quantity, and dependence on combustible and electronic cigarettes was used to identify classes. Demographics and additional smoking and vaping variables were used to further characterize the classes.
Setting
United States.
Participants
A total of 2896 adults who smoked weekly for the past year and vaped weekly for the past month.
Measurements
Self‐report baseline measures assessed demographics and smoking and vaping behaviors and characteristics including days of use per week, frequency of use within a day, time to first use after waking, urges to smoke, smoking cessation motivation, self‐efficacy to abstain from smoking, months since vaping initiation, reasons for initiating and maintaining vaping, and future plans to stop vaping.
Findings
Eight probabilistic classes were identified and well‐defined (relative entropy = 0.95, Lo–Mendell–Rubin adjusted likelihood ratio test P < 0.0001; class probabilities 0.89–0.97). In general, classes crossed two levels of smoking with four levels of vaping. The largest class (31%) had relatively high levels of smoking (72% daily, 56% 11+ cigarettes per day CPD, 96% within 30 minutes of waking) and vaping (74% daily, 100% 20+ electronic‐CPD, 74% <30 minutes). The next largest class (27%) had relatively high levels of vaping (93% daily, 100% 20+ electronic‐CPD, 82% <30 minutes) and very low levels of smoking (28% daily, 12% 11+ CPD, 0% <30 minutes). The six smaller classes (3%–13%) also had distinct smoking and vaping behaviors. All eight classes exhibited distinguishing characteristics beyond current smoking and vaping behaviors.
Conclusions
Dual users of combustible and electronic cigarettes are not a homogeneous population, having eight well‐defined prospective subpopulations.
Background and Aims
Most e‐cigarette users who also smoke combustible cigarettes (dual users) begin vaping to quit smoking, yet only a subset succeeds. We hypothesized that reinforcing ...characteristics of e‐cigarettes (vaping reinforcement) would positively predict smoking cessation propensity (SCP) among dual users.
Design
Secondary analysis of cross‐sectional baseline data from dual users in an ongoing smoking cessation trial. Exploratory and confirmatory factor analysis (EFA and CFA) created latent variables for vaping reinforcement and SCP. A structural equation modeling (SEM) approach was used to test the hypothesis.
Setting
United States.
Participants
A national sample of dual users of combustible and electronic cigarettes who smoke and vape at least once per week (n = 2896) were enrolled (63% male; mean age = 29.9 years) into a randomized controlled trial in which they would receive either smoking cessation materials or no smoking cessation materials.
Measurements
Vaping reinforcement was indexed by vaping frequency (days/week vaping, times/day vaping, puffs/e‐cigarette use), e‐cigarette characteristics numbers of modifications and tobacco or non‐tobacco flavors, nicotine content (mg) and positive e‐cigarette expectancies. SCP was measured by items of confidence, commitment to being smoke‐free, cessation motivation (contemplation ladder), change in cigarettes per day since beginning e‐cigarette use and negative smoking expectancies.
Findings
Four factors emerged from the EFA: vaping propensity (vaping frequency, positive expectancies), vaping enthusiasm (e‐cigarette modifications, using non‐tobacco flavors, puffs per use), nicotine/tobacco flavor (nicotine strength, tobacco flavors) and SCP (negative expectancies about smoking, motivation to quit smoking, reduction in smoking). A CFA upheld the exploratory factor structure root mean square error of approximation (RMSEA) = 0.046, CFI = 0.91. An SEM with the three vaping latent variables directly predicting SCP had good model fit (RMSEA = 0.030, CFI = 0.97) with a positive relationship of vaping propensity (0.509, P < 0.001), and small negative relationships of vaping enthusiasm (−0.158, P = 0.014) and nicotine/tobacco flavor (−0.230, P < 0.001).
Conclusions
Among e‐cigarette users who also smoke combustible cigarettes, frequent vaping combined with positive e‐cigarette expectancies appears to predict greater smoking cessation propensity. However, vaping enthusiasm (measured by e‐cigarette modifications, using non‐tobacco flavors and puffs per use), higher nicotine content and use of tobacco flavored solution may reduce cessation propensity.
Most users of electronic cigarettes (e-cigarettes) report initiating use to quit combustible cigarettes. Nevertheless, high levels of dual use (i.e., using both combustible cigarettes and ...e-cigarettes) occur among adults. Using formative data from in-depth interviews and employing learner verification, we adapted an existing, validated self-help smoking-cessation intervention (Stop Smoking for Good; SSFG) to create a targeted intervention for dual users, If You Vape: A Guide to Quitting Smoking (IYV). In Phase I, in-depth interviews (
= 28) were conducted to assess relevance of the existing
materials (10 booklets, nine pamphlets) and identify new content for the booklets. Next, for Phase II, learner verification interviews (
= 20 dual users) were conducted to assess their appeal and acceptability. Several key themes emerged from the Phase I in-depth interviews. Findings led to the inclusion of e-cigarette-specific strategies used by successful quitters such as gradually reducing nicotine levels, switching from tobacco flavor to alternative flavors, and limiting e-cigarette use to places one would normally smoke (i.e., not expanding use). Suggestions from Phase II learner verification included broadening the visual appeal for a younger, more diverse demographic, expanding tips for quitting smoking via e-cigarettes, and expanding terminology for e-cigarette devices. Beginning with an efficacious self-help intervention, we used a systematic process to develop a version specifically for dual users.
BACKGROUNDAlthough many smokers use electronic cigarettes (e-cigarettes) to quit smoking, most continue to smoke while vaping. This dual use might delay cessation and increase toxicant exposure. We ...aimed to test the efficacy of a self-help intervention designed to help dual users to quit smoking. METHODSIn this three-arm randomised controlled trial we recruited individuals in the USA using Facebook and multimedia advertisements. Included participants were 18 years or older, smoked at least weekly in the preceding year, and vaped at least weekly in the preceding month. We used computer generated randomisation with balanced-permuted blocks (block size 10, with 2-4-4 ratio) to allocate participants to assessment only (ASSESS group), generic smoking cessation self-help booklets (GENERIC group), or booklets targeting dual users (eTARGET group). Individuals in the generic or targeted intervention groups received monthly cessation materials for 18 months, with assessments every 3 months for 24 months. The main outcome was self-reported 7-day point-prevalence smoking abstinence at each assessment point. All randomly allocated participants were included in primary analyses using generalised estimating equations for each of 20 datasets created by multiple imputation. Analysis of the χ2s produced an F test. The trial is registered with ClinicalTrials.gov, NCT02416011, and is now closed. FINDINGSBetween July 12, 2016, and June 30, 2017, we randomly assigned 2896 dual users (575 to assessment, 1154 to generic intervention, and 1167 to targeted self-help). 7-day point-prevalence smoking abstinence increased from 14% at 3 months to 42% at 24 months (F7,541·7=67·1, p<0·0001) in the overall sample. Targeted self-help resulted in higher smoking abstinence than did assessment alone throughout the treatment period (F1,973·8=10·20, p=0·0014 α=0·017). The generic intervention group had abstinence rates between those of the assessment and targeted groups, but did not significantly differ from either when adjusted for multiple comparisons (GENERIC vs eTARGET F1,1102·5=1·79, p=0·18 α=0·05; GENERIC vs ASSESS F1,676·7=4·29, p=0·039 α=0·025). Differences between study groups attenuated after the interventions ended. INTERPRETATIONA targeted self-help intervention with high potential for dissemination could be efficacious in promoting smoking cessation among dual users of combustible cigarettes and e-cigarettes. FUNDINGNational Institute on Drug Abuse, National Cancer Institute.
Electronic Nicotine Delivery Systems, also called electronic cigarettes or e-cigarettes, have been available for over a decade and use has been increasing dramatically. The primary reported reasons ...for use are to aid smoking cessation or reduction, yet a significant proportion appear to be long-term users of both products (“dual users”). Dual users may be motivated to quit smoking and might benefit from a behavioral intervention for smoking cessation. This paper describes the intervention development, as well as the design, methods, and data analysis plans for an ongoing randomized controlled trial (RCT). Formative research and learner verification were conducted to create a usable, understandable, and acceptable self-help intervention targeting dual users. The efficacy is being tested in an RCT with current dual users (N=2900) recruited nationally and randomized to one of three conditions. The Assessment Only (ASSESS) group only completes assessments. The Generic Self-Help (GENERIC) group receives non-targeted smoking cessation booklets and supplemental materials sent monthly over 18months. The e-cigarette Targeted Self-Help (eTARGET) group receives the newly developed intervention (targeted booklets and supplemental materials) sent over the same period. All participants complete self-report surveys every 3months over 2years. The primary study outcome is self-reported 7-day point prevalence abstinence. Cost-effectiveness metrics for the GENERIC and eTARGET interventions will also be calculated.
This study aimed to systematically review the literature on e-cigarette use in New Zealand, focusing on prevalence, rationale for use, perceptions and exposure to the devices.
Six databases were ...systematically searched for articles regarding e-cigarette use in New Zealand, supplemented with a grey literature search. Seven hundred and eighteen abstracts were identified and full text of 100 articles reviewed. Studies addressing prevalence of and rationale for use, perceptions of and exposure to e-cigarettes were included. Relevant data were synthesised in a narrative summary.
Fourteen studies addressed aspects of e-cigarette use in New Zealand, published between 2010 and 2017. Ever-use of e-cigarettes among adults and adolescents has increased, although current use remains low. Smoking strongly predicts use, and ever-use may decrease with age. Investigation of other predictors has been hindered by low prevalence and small samples. While curiosity is commonly cited for sampling e-cigarettes, many smokers are drawn by harm reduction or cessation. More complex motivators are becoming evident. Although exposure to e-cigarettes is common, many remain uncertain about their harm relative to tobacco.
While the available evidence provides an overview of current use, exposure and acceptance of e-cigarettes in New Zealand, it highlights knowledge deficits and informs future monitoring.
The authors attempted to contact all 157 graduates from the University of Auckland's Master's in Public Health (MPH) program who completed theses from 1991 to 2005 about publications arising from ...their research. Of the 104 students contacted, 77 (74%) completed the questionnaire: 34 (45%) submitted a total of 46 articles, 31 (66%) of which were accepted or published. An expectation of publication and being supported financially were both associated with submission for publication. The most commonly reported barriers were lack of time (62%), lack of staff support (35%), and low confidence in ability to write (29%). For those regarding time as a barrier, work demands were commonly cited (90%). Sustained commitment from supervisors plus practical support (seminars, workshops, and cosupervision) was considered likely to be helpful. More effective supervisor–student engagement, funding, and setting an expectation of publication could increase MPH research outputs, but the additional supervisor workload must be realistic.
Understanding the mechanisms behind host cell invasion by
remains a major hurdle to developing antimalarial therapeutics that target the asexual cycle and the symptomatic stage of malaria. Host cell ...entry is enabled by a multitude of precisely timed and tightly regulated receptor-ligand interactions. Cyclic nucleotide signaling has been implicated in regulating parasite invasion, and an important downstream effector of the cAMP-signaling pathway is protein kinase A (PKA), a cAMP-dependent protein kinase. There is increasing evidence that
PKA (PfPKA) is responsible for phosphorylation of the cytoplasmic domain of
apical membrane antigen 1 (PfAMA1) at Ser610, a cAMP-dependent event that is crucial for successful parasite invasion. In the present study, CRISPR-Cas9 and conditional gene deletion (dimerizable cre) technologies were implemented to generate a
parasite line in which expression of the catalytic subunit of PfPKA (PfPKAc) is under conditional control, demonstrating highly efficient dimerizable Cre recombinase (DiCre)-mediated gene excision and complete knockdown of protein expression. Parasites lacking PfPKAc show severely reduced growth after one intraerythrocytic growth cycle and are deficient in host cell invasion, as highlighted by live-imaging experiments. Furthermore, PfPKAc-deficient parasites are unable to phosphorylate PfAMA1 at Ser610. This work not only identifies an essential role for PfPKAc in the
asexual life cycle but also confirms that PfPKAc is the kinase responsible for phosphorylating PfAMA1 Ser610.
Malaria continues to present a major global health burden, particularly in low-resource countries.
, the parasite responsible for the most severe form of malaria, causes disease through rapid and repeated rounds of invasion and replication within red blood cells. Invasion into red blood cells is essential for
survival, and the molecular events mediating this process have gained much attention as potential therapeutic targets. With no effective vaccine available, and with the emergence of resistance to antimalarials, there is an urgent need for the development of new therapeutics. Our research has used genetic techniques to provide evidence of an essential protein kinase involved in
invasion. Our work adds to the current understanding of parasite signaling processes required for invasion, highlighting PKA as a potential drug target to inhibit invasion for the treatment of malaria.
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