Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
Sze Lin Yoong1,2,3, Flora Tzelepis1,2,3, John Wiggers1,2,3, Christopher Oldmeadow1,3, Li Kheng Chai1, Christine Paul1,3, Melanie Kingsland1,2,3, Luke Wolfenden1,2,3
1. School of Medicine and Public Health, University of Newcastle, Callaghan, New South Wales 2308, Australia
2. Hunter New England Population Health, Hunter New England Local Health District, Wallsend, New South Wales 2287, Australia
3. Hunter Medical Research Institute, Lot 1, Kookaburra Circuit, New Lambton Heights, New South Wales 2305, Australia
Document prepared for the World Health Organization This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Contents
Acknowledgements 6
Executive summary 7 Background 7 Objectives 7 Methods 7 Results 8 Conclusions 10
1. Background 11
2. Objectives 13
3. Methods 14 3.1 Inclusion criteria 14 3.2 Search strategy 15 3.3 Screening and data extraction 16 3.4 Critical appraisal 16 3.5 Data synthesis 17 3.5.1 Objective 1 17 3.5.2 Objective 2 18
4. Results 19 4.1 Eligible studies and study characteristics 19 4.1.1 Objective 1 19 4.1.2 Objective 2 20 4.2 Risk of bias 34 4.2.1 Objective 1 34 4.2.2 Objective 2 34 4.3 Overall prevalence of SEIS use among young people (objective 1) 34 4.4 Prevalence among non-smokers (objective 1) 36 This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4.5 Prevalence among current smokers (objective 1) 37 4.6 Exploring heterogeneity (for objective 1) 37 4.7 Objective 2 38
5. Discussion and conclusion 40 5.1 Discussion 40 5.2 Conclusion 42
References 43
Annexes 49
5 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Acknowledgements The authors would like to acknowledge Debbie Booth for running the database search and Christophe Lecathelinais and Alessandra Bisquera for statistical support.
Declaration of conflict of interest All authors declare no conflict of interest.
6 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Executive summary
Background Tobacco smoking remains a leading cause of death and disability worldwide. E-cigarettes (referred to here as smoking-proxy electronic inhaling systems, or SEIS) are marketed as having the potential to aid smoking cessation among current smokers, but may also be associated with increased likelihood of initiating tobacco smoking for non-smokers. A number of studies have suggested an increasing trend in SEIS use among youths, particularly among non-tobacco smokers. A positive association between SEIS use and tobacco use has been consistently reported in cross-sectional studies. To better understand the potential impact of SEIS use by young people, a synthesis of evidence regarding the prevalence and trends of SEIS use among this group is required, as is a synthesis of longitudinal data on the association between SEIS and future tobacco cigarette use.
Objectives The objectives of the study are as follows:
1. To describe among young people (aged 10–20 years) the population prevalence and trends in prevalence of smoking-proxy electronic inhaling system (SEIS) use overall and among non-smokers and current smokers by country and by sex.
2. To synthesize findings from longitudinal studies of SEIS use by young people (aged ≤ 20 years) and its association with initiation of tobacco cigarette use.
Methods A systematic review of the peer-reviewed and grey literature was undertaken in December 2015. Studies were included for objective 1 if they described the prevalence of SEIS use in a general population sample of young people aged ≤ 20 years in a defined geographical region using census or probability sampling. Studies where participants were recruited based on a specific health condition or as members of particular socioeconomic groups were excluded. There were no restrictions regarding the location of study, peer review status or language. A sensitivity analysis was undertaken including studies that did not include probability sampling but sampled for representativeness.
7 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
For objective 2, studies were included if they used a prospective longitudinal cohort design and assessed the association between SEIS use in young people aged ≤ 20 years at baseline and later use of combustible tobacco products. There were no restrictions on study sampling or recruitment methods, location of the study, peer review status or language of publication.
A single-search strategy for both objectives was employed that encompassed electronic databases of peer-reviewed manuscripts, grey literature Google searches, hand searches of relevant reference lists and consultation with experts in the field. Screening and data extraction were undertaken by three reviewers for peer-reviewed research and one reviewer for grey literature.
For both objectives, data from included studies were combined using random effect meta-analyses. To provide estimates of the prevalence of SEIS use in the previous three years, pooled estimates of “ever use” or “use in last 30 days (‘current use’)” of SEIS are also reported from studies using data collected between 2013 and 2015. To describe trends in prevalence of SEIS use, changes in prevalence of “ever use” or “use in last 30 days” over time for all studies between 2008 and 2015 were pooled, and described narratively by country where multiple comparable prevalence estimates were available during this time. All analyses were repeated for both current and non-current cigarette smokers. This analysis was repeated in a sensitivity analysis including four additional studies that did not use probability sampling but had sampled to be representative of the population.
Results
Included studies Objective 1. Overall, 2281 abstracts were screened (2246 electronic databases, 19 reports from the Google search and 16 reports from expert contacts). From these, 135 full texts were obtained for full-text screening, of which 28 publications reporting findings from 35 studies (each study represents a single survey) were included. An additional four publications reporting on findings from six studies were included in the sensitivity analysis. All studies utilized self-reported questionnaires to assess SEIS use. Eight of 32 studies satisfied seven of 10 quality assessment criteria, 17 satisfied five or six criteria, and seven satisfied three or four criteria. None of the studies reported on the reliability of the measures employed.
Objective 2. Overall, 2281 articles were screened and 119 full texts were obtained for further screening, with three studies being included in the final meta-analysis. All studies were undertaken in the United States of America. None of the studies were classified as having a sample representative of the target population and one study had a small sample of SEIS users at baseline (n=16). For all studies it was unclear whether the self-reported methods for collecting data on SEIS use and subgroup characteristics were reliable.
8 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Overall prevalence of SEIS use among overall sample (a) Ever use. The pooled estimate of the prevalence of SEIS ever use from 20 studies conducted between 2013 and 2015 was 16.4% (95% CI: 12.5–20.6%). Prevalence of ever use was 17.4% (95% CI: 10.9–25%) among males (from 14 studies) and 14.3% (95% CI: 8.7–21%) among females (from 14 studies). In the sensitivity analyses (23 studies), the prevalence of ever use was 16.1% (95% CI: 12.6–20.0%) overall, 19.3% (95% CI: 12.5–27.1%) among males and 15.5% (95% CI: 9.9–22.2%) in females (13 studies).
With one exception (Italy), for all five countries where multiple comparable prevalence estimates were available between 2008 and 2015, the prevalence of ever use increased over time (New Zealand, Poland, Republic of Korea, United States).
(b) Current use. The pooled estimate of the prevalence of current SEIS use from 19 studies conducted between 2013 and 2015 was 5.6% (95% CI: 3.4–8.3%). The prevalence of current use was 6.3% (95% CI: 3.7–9.6%) among males and 4.3% (95% CI: 2.4–6.8%) in females (12 studies). In the sensitivity analyses with an additional five studies (24 studies), the prevalence of SEIS ever use was 5.5% (95% CI: 3.5–7.9%) overall, 7.4 % (95% CI: 4.5–10.8%) among males and 4.9% (95% CI: 2.8–7.4%) in females (13 studies).
In three of the five countries where multiple comparable estimates of prevalence were available between 2008 and 2015, prevalence of current use increased (Poland, United Kingdom, United States). The prevalence of current SEIS use decreased in Hungary between 2012 and 2013, while the prevalence remained stable in Italy.
Prevalence among non-smokers (a) Ever use. The pooled estimate of the prevalence of ever use among non-smokers from 13 studies conducted between 2013 and 2015 was 7.0% (95% CI: 5.1–9.3%). In the sensitivity analyses with an additional three studies, the prevalence of SEIS ever use was 6.4% (95% CI: 4.6–8.5%) among non-smokers.
Multiple estimates of prevalence over time in the United States indicated that ever use by non-smokers increased. In contrast, the prevalence of such use did not change in Italy.
(b) Current use. The pooled estimate of the prevalence of current SEIS use among non-smokers from nine studies conducted between 2013 and 2015 was 1.5% (95% CI: 0.3–3.5%). In the sensitivity analyses with an additional four studies (15 studies), the prevalence of SEIS ever use among non-smokers was 1.3% (95% CI: 0.4–2.8%).
Comparable estimates of prevalence of current use by non-smokers over time were available between 2008 and 2015 from three countries: Italy, Poland and the United States. In the United States, the prevalence of current use in non-smokers increased in both middle school- and high school-aged students between 2011 and 2014. In Poland, the prevalence of use increased, while in Italy prevalence was 0% across all periods of data collection.
9 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Prevalence among current smokers (a) Ever use. The pooled estimate of the prevalence of SEIS ever use among current tobacco smokers from 13 studies conducted between 2013 and 2015 was 54.7% (95% CI: 45.9–60.5%). In the sensitivity analyses with an additional two studies (15 studies), the prevalence of SEIS ever use was 53.2% (95% CI: 45.9 –60.5%) among current smokers.
In the United States, the prevalence of SEIS ever use among current tobacco smokers increased, while it remained stable in Italy.
(b) Current use. The pooled estimate of the prevalence of SEIS current use among current tobacco smokers from 10 studies conducted between 2013 and 2015 was 19.4% (95% CI: 8.3–33.5%). In the sensitivity analyses with an additional two studies (14 studies), the prevalence of SEIS ever use was 17.8% (95% CI: 8.8–28.9%).
Multiple comparable estimates of prevalence of SEIS use across 2008–2015 in Poland and the United States showed an increase in current use of SEIS among smokers. In Italy, prevalence remained stable.
Association between SEIS ever use and tobacco cigarette use Three studies conducted in the United States were included in the analysis, with each study indicating that non-tobacco-smoking young people who were SEIS users were significantly more likely to be tobacco smokers at follow-up. Pooled analysis of the studies indicated that SEIS smokers at baseline had an increased adjusted odds ratio (AOR 2.19; 95% CI: 1.46–3.3%; I2 = 59.7%) of being a tobacco cigarette user at follow-up.
Conclusions This systematic review and meta-analysis found substantial differences in prevalence and changes in prevalence of SEIS use by country. More than half of all young tobacco smokers in Canada, Ireland, New Zealand, the United Kingdom and the United States had ever used SEIS. Use of SEIS among young people was reportedly increasing in Poland and the United States but not in some other countries, for example Hungary and Italy. Pooled findings from two longitudinal studies indicated that the use of SEIS by non-smokers more than doubled the odds of tobacco smoking at follow-up.
Despite current low prevalence of SEIS use among non-smoking young people in most jurisdictions, the finding of a longitudinal association between SEIS use and subsequent tobacco use, and the increasing prevalence of SEIS use among non-smoking young people in some countries, supports the need for strategies to discourage SEIS uptake among non-smokers.
10 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
1. Background
Internationally, tobacco use is the leading cause of preventable death and disability (1). The 2013 Global Burden of Disease Study reported that tobacco use accounted for 6.1 million deaths and 143.5 million disability-adjusted life-years globally (2). While there is considerable between-country variation in the current prevalence of tobacco use, the global prevalence declined between 1980 and 2012 from 41.2% to 31.1% for men and 10.6% to 6.2% for women (3). Globally, the largest annualized rate of change over this period occurred among those aged 15–19 years, where the rate declined by 1.8% each year (3). Given the significant health and societal burden of tobacco use (2), comprehensive strategies to prevent initiation and assist cessation have been recommended (4).
There has been considerable debate about the potential role of e-cigarettes in addressing tobacco use, particularly among young people (5, 6). Electronic cigarettes (referred to here as smoking-proxy electronic inhaling systems, or SEIS) are battery-operated devices designed to deliver a solution as an aerosol (or “vapour”) typically made up of propylene glycol or glycerol (glycerine), nicotine, and flavouring agents, which is inhaled by users (7). The devices are designed to simulate the act of smoking tobacco cigarettes to allow the consumption of nicotine without the burning of tobacco. SEIS has been primarily marketed as an alternative to combustible tobacco, as an aid to reduce or cease tobacco smoking or a means of using nicotine in smoke-free environments (7). To date, the impact of SEIS in aiding smoking cessation is equivocal, with a recent Cochrane review reporting a small positive effect from only two randomized controlled trials (8). Concerns regarding the long-term safety of the use of SEIS however have led to at least 55 countries introducing legislation or bans prohibiting or restricting the sale of SEIS (9).
Since their introduction, the use of SEIS among young people has received considerable attention. A 2014 systematic review reported increasing use of SEIS among young people in countries such as Poland and the United States since 2011 (10). Findings from the review highlighted some differences in patterns of SEIS use among young people compared to older individuals, with a significantly greater proportion of adolescent
11 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
SEIS ever users reporting no previous use of tobacco cigarettes. Similarly, a national study in Poland reported that over 20% of adolescent SEIS users were non-tobacco smokers (11); and in some United States jurisdictions, SEIS use among adolescents exceeded traditional tobacco cigarette use (12). While a small proportion of young adults report using SEIS to aid cessation (13, 14), studies suggest that younger adults are more likely to use SEIS primarily for experimentation purposes (10, 13).
The increasing rate of SEIS use among young people generally and among non-smokers in particular has led to concerns that SEIS use and particularly experimentation by young people could lead to nicotine dependence into adulthood and subsequent tobacco initiation (15). The potential mechanisms driving this process are unknown, though a recent review proposed a number of hypothesized pathways that may account for the initial uptake of SEIS and the transition between SEIS experimentation and nicotine dependence (16). To date, however, such concerns that SEIS use may lead to tobacco uptake have primarily been examined via cross-sectional studies. These studies reported positive associations between SEIS use and tobacco smoking behaviour among youths who had not previously used tobacco (17–19). In the absence of longitudinal studies, such findings do not allow for the examination of causality and directionality (i.e. whether SEIS use leads to initiation of tobacco smoking).
A synthesis of the current prevalence and patterns of SEIS use among young smokers and non-smokers is needed to better understand the potential impacts of SEIS use on adolescent tobacco smoking behaviour. Further, a synthesis of longitudinal data regarding the association between SEIS and tobacco smoking by young people is needed to allow examination of the potential impact of SEIS use on subsequent tobacco smoking and other forms of combustible tobacco use. For the purpose of this systematic review, “young people” have been defined as those aged 10–20 years and “adolescents” have been defined as those aged 15–19 years, consistent with WHO definitions.
12 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
2. Objectives
The objectives of the study are as follows:
1. To describe among young people (aged ≤ 20 years) the population prevalence and trends in prevalence of smoking-proxy electronic inhaling system (SEIS) use overall and among non-smokers and current smokers by country, sex and SEIS type.
2. To synthesize findings from longitudinal studies of SEIS use by young people (aged ≤ 20 years) and initiation of tobacco cigarette use.
13 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
3. Methods
A systematic review of the peer-reviewed and grey literature was undertaken between August and December 2015. The review was conducted in accordance with the Cochrane Collaboration review methods and involved searching multiple electronic databases, using two independent reviewers, undertaking formal critical appraisal with the Joanna Briggs Institute critical appraisal checklist for studies reporting prevalence data (20), and undertaking meta-analysis where appropriate.
3.1 Inclusion criteria
Objective 1. For this objective, studies were included if they described the prevalence of SEIS use in the general population within a defined geographical region (such as province, state or country). To be eligible studies needed to employ census or probability sampling methods, and report SEIS use in young people with a mean age of between 10 and 20 years. For studies that included those aged over 20 years, the study was included if a subgroup analysis of SEIS use among those aged ≤ 20 years was reported. Studies reporting any measure of SEIS (e.g. self-reported, secondary (or proxy) reported or biochemical assessments) were included.
Studies using data from specialist panels (such as online research panels) or cohort studies that did not employ probability sampling procedures and recruitment procedures were excluded, regardless of whether population weights were applied to estimates of SEIS use. Probability sampling has been identified as an important requirement of quality prevalence studies (21). Studies where participants were recruited based on a pre-existing disease or condition (e.g. mental health, hospital), or on the basis of specific socioeconomic characteristics (e.g. located in a lower socioeconomic region) and disease characteristics (e.g. patients with cardiovascular disease), were also excluded. Finally, non-databased publications that did not present new data (e.g. commentaries and opinion pieces) were excluded. There were no other restrictions regarding the location of the study, peer review status or language of publication.
14 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Objective 2. For this objective, studies employing prospective longitudinal cohort designs that aimed to assess the association of SEIS use in young people and initiation of combustible tobacco products were included. Cross-sectional, case control and retrospective studies were excluded as they did not allow direct examination of causality, as were non-databased publications that did not present new data. To be eligible, longitudinal cohort studies needed to include non-smokers with a mean age of between 10 and 20 years at baseline and examine tobacco use at follow-up. Studies reporting any measure of SEIS use (e.g. self-reported, secondary (or proxy) reported or biochemical assessments) and that examined tobacco smoking use at follow-up were included. There were no other restrictions on study sampling or recruitment methods, location of the study, peer review status or the language of publication. No restrictions on sampling methods were employed for this objective as the primary aim was to assess association between baseline SEIS use and tobacco cigarette uptake.
3.2 Search strategy A single-search strategy was employed to identify relevant peer-reviewed and grey literature for both objectives. The search encompassed electronic databases of peer- reviewed manuscripts, Google searches, hand searches and consultation with experts in the field.
• Electronic databases. A systematic search of the electronic databases MEDLINE, EMBASE, PsycInfo, Cochrane and CINAHL was undertaken by an experienced academic librarian. Search terms for SEIS were based on those used in previous systematic reviews of SEIS use (8, 22). Broadly, the search terms included e-cig*, electronic nicotine*, electronic hookah* and e-hookah* as Medical Subject Headings (MeSH) terms. The full search string for each electronic database is provided in Annex 1.
• Google search. Searches were undertaken to identify potentially eligible reports, papers and conference abstracts for inclusion. The terms “electronic cigarette” and “ecigarette” were entered into separate Google.com searches. The results listed on the first 75 pages (750 hits) of each search were examined for relevant grey literature.
• Hand searches. Relevant references examining SEIS use in young people identified in the searches above were examined for potentially eligible studies for inclusion. The reference lists of all eligible studies were also screened for any additional studies potentially relevant to the objectives of this review.
• Experts in the field. Additional information about SEIS use in young people was sought from experts recommended by the Tobacco Unit of the World Health Organization and from selected authors who had published two or more relevant studies in the SEIS field. Experts were asked to identify any published or unpublished manuscripts (e.g. reports, papers, conference abstracts) or additional data relevant
15 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
to the report objectives. An email was sent to 15 experts on 31 August 2015. One respondent suggested an additional two experts be contacted and an email was sent to these experts on 11 September 2015. One respondent also contacted a further 13 experts on 13 September 2015. Given the rapid progress in the SEIS field, this process was repeated by sending another email to these experts on the 16 December 2015 asking whether they had any recent unpublished data that was relevant to this review. The experts were located in Australia, Canada, Germany, Italy, Romania, the United Kingdom and the United States.
3.3 Screening and data extraction EndNote version X6.0.1 software (Thomson Reuters, PA, United States) was used to manage study inclusion and filter duplicate studies. SLY and LW1 screened all databased results and FT screened all citations from the grey literature search. The full texts of all potentially eligible studies were obtained and study eligibility was determined based on assessment of the full text. Where eligibility was unclear, authors were contacted to request additional information. “Google translate” was used to assist with assessing the eligibility of non-English language manuscripts (n=25), which were all excluded prior to the full-text screening.
SLY, LW or LKC extracted the following information for all included studies in objective 1: author name, publication year, country of study, sample size, participant age range and sex, year of data collection, data collection modality, sampling procedures, measure of SEIS use, type of SEIS used (e.g. e-hookah), prevalence of SEIS use by sex, and prevalence of SEIS use among smokers and non-smokers (including n, percentages and 95% confidence intervals, where available) (see Annex 2). A consensus process was used to resolve any differences in extraction. Data for total denominators were also obtained from other sources (e.g. other references or raw datasets) to allow for inclusion in the meta-analysis. For objective 2, author last name, year of publication, participant characteristics (mean age), study design, country, sampling frame, outcomes, data collection modality, analyses, odds ratio and 95% CI, covariates adjusted for and follow-up time points were extracted by SLY. For the included studies, other supporting publications or reports (for example protocols, full descriptions of study methods from government websites) were also sought to obtain relevant information where the data from the primary study were absent or unclear. Data extraction was undertaken using prepiloted data extraction forms developed for the purpose of the study.
3.4 Critical appraisal Two reviewers (MK and FT) independently undertook critical appraisal using the Joanna Briggs Institute critical appraisal checklist for studies reporting prevalence data (20). The instrument contains 10 items examining the following study characteristics: sample representativeness, sampling methods, adequacy of sample size, participant and setting descriptions, coverage of sample, objectivity of criteria, reliability of measurement,
1 Authors’ initials: see list of authors.
16 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. appropriateness of statistical analysis, confounding factors identified and accounted for, and objective classification of subpopulations (Yes; No; Unclear; and N/A). This tool has been found to have face validity and to be acceptable and easy to use (23).
For objective 2, in addition to completing the Joanna Briggs Institute critical appraisal checklist for studies reporting prevalence data assessment (20), the reviewers also examined the following study characteristics for the longitudinal studies: whether the outcome of interest (tobacco smoking) was absent at baseline, whether known confounders were adjusted for in the analysis, and whether there was appropriate treatment of missing data. For both objectives, where discrepancies in coding emerged between reviewers, inconsistent ratings were discussed between the reviewers until consensus was reached.
3.5 Data synthesis All analyses were undertaken using Stata version 14 software (StataCorp, College Station, TX, United States) and the Metaprop and Metareg packages. For both objectives, main findings from the individual studies were also described narratively where relevant.
3.5.1 Objective 1 Data from included studies were combined using a random effect meta-analysis, weighted according to the inverse variance method. The Freeman-Tukey double arcsine transformation of prevalences was also used to allow for studies with prevalences that were close to zero. Exact 95% confidence intervals for the individual studies were computed.
Pooled estimates of SEIS ever use, and use in last 30 days (“current use”), were reported as stratified by country and sex (where available). Studies that included occasional users were pooled with ever users; and studies that reported regular use were pooled with last 30 days (or current use). Pooled estimates of ever and current SEIS use among non-smokers and smokers were also reported as stratified by country. Estimates of non- smokers included those not currently smoking (including ex-smokers) where available, and estimates of smokers included those reporting using any tobacco (including experimenters and occasional or current users) where available. Where prevalence of SEIS use by current smokers and non-smokers was not specifically reported, estimates of use were calculated using the following information provided in the original publications: number in total sample, prevalence of SEIS users, prevalence of smokers, and prevalence of concurrent SEIS and tobacco users. Estimates of regular/occasional use were available for four studies (24–27). Where individual studies provided weighted and unweighted measures of SEIS prevalence, weighted estimates were used. Pooled estimates of prevalence are reported as an absolute percentage with 95% confidence intervals. Heterogeneity was assessed using the I-squared statistic and reported for each point estimate, together with the chi-square statistic from the likelihood ratio test comparing the random and fixed effects model, the estimated between-study variance and its test of significance. For pooled estimates of current or ever use, this analysis
17 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. was repeated in a sensitivity analysis, including studies that did not use probability sampling but attempted to sample in a way that was representative of the population.
To explore additional potential causes of heterogeneity, an exploratory meta-regression was performed with prevalence of ever and current SEIS use among young people overall and by smokers and non-smokers. Covariates included in this analysis included year of data collection, age, sex and country policies regarding the availability and marketing of SEIS to adolescents (classed as consumer product (no regulation), minimum age of purchase overall or banned overall), and MPOWER scores for 2014. Classification for SEIS regulation was made based on a previously published review examining SEIS policy internationally (9). MPOWER scores (out of 100) for countries included in the review were provided by a representative from the World Health Organization. MPOWER scores were introduced following the WHO Framework Convention on Tobacco Control, and are calculated based on six measures that are considered central to tobacco control policies: taxes and pricing; advertising, promotion and sponsorship; protection against second-hand smoke; public warnings against the dangers of tobacco smoking; providing cessation support to those intending to quit; and monitoring policies (1). The multivariable model that explained the most between-study variance was reported.
3.5.2 Objective 2 To assess whether use of SEIS at baseline was associated with cigarette use at follow- up, a random effects meta-analysis was undertaken with adjusted log odds ratios. The pooled estimates of the odds ratio with 95% confidence intervals were reported.
18 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4. Results
4.1 Eligible studies and study characteristics
4.1.1 Objective 1 Overall, 2281 abstracts were obtained and screened (2246 electronic databases; 19 reports from the Google search and 16 reports from expert contacts). From these, 135 full texts where eligibility was unclear were obtained for full-text screening. Of these, 28 publications that reported findings from 35 studies (each study represents a single survey) were included in the final meta-analyses for at least one of the outcomes. Of those included in the full-text screening, studies were excluded because they examined SEIS use only in individuals aged > 20 (n=55), did not report on prevalence of SEIS use (n=4), did not use probability sampling (n=4), did not sample to be representative of the region (n=14), were not empirical studies (n=12), or included findings previously reported in other published papers (n=18) (Figure A4.1)2. The four studies that described population prevalence but did not use probability sampling were included as part of a sensitivity analysis.
The included publications were conducted in 11 high-income countries: the United States (national and subnational) (n=11) (12, 19, 28–36), Republic of Korea (n=2) (37, 38), New Zealand (n=2) (26, 39), United Kingdom (Scotland and Wales) (n=2) (27, 40), Poland (n=2) (11, 41), Hungary (n=1) (42), Canada (n=2) (43, 44), Hong Kong Special Administrative Region (n=1) (17), France (n=1) (45), Ireland (n=1) (24), Italy (n=1) (25), Iceland (n=1) (46) and Greece (n=1) (47). These studies were conducted between 2008 (37) and 2015 (25), and sample size ranged from 99 (39) to 75 643 (38). Two studies included both young people and adults as part of their sample but presented findings separately for young people (n=99 and n=160–163) (25, 26). All studies reported estimates for young people under 20. All studies utilized self-reported questionnaires completed by participants administered via paper and pencil (n=23) (11, 12, 17, 19, 24, 27–33, 36, 37, 39–42, 44–47), web (n=2) (38, 48), telephone (n=1) (43) or face to face (n=2) (25, 26). Studies either assessed ever use of SEIS (n=23) (11, 24–31, 33, 35–41,
2 Note: all figures are contained within Annex 4.
19 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
43–48) or use in past 30 days (“current use”) (n=21) (11, 12, 17, 24–33, 35, 36, 38, 40–43, 47). Four publications also reported regular or occasional use (see Annex 3 for measures) (24–27). Dutra and Glantz (19) reported on the same dataset as Corey et al. (31) (United States National Youth Tobacco Survey 2012 and 2013), but presented findings by smokers and non-smokers. Overall prevalence was included in the meta- analysis only once for these studies. None of the studies examined types of SEIS used. Seventeen publications (reporting on 22 studies) (11, 17, 19, 24, 25, 27, 30, 33, 37–42, 46, 47) reported prevalence of SEIS use by current smokers and non-smokers, but none provided these estimates by sex. An additional four studies conducted in Switzerland (49) and the United Kingdom (50–52) were included in the sensitivity analyses. Study characteristics are reported in Table 1.
4.1.2 Objective 2 For objective 2, 2281 articles were screened and 119 full texts were obtained for further screening, with three studies meeting the eligibility criteria and included in the review (Figure A4.2) (54–56). Studies included in the full-text screening were excluded primarily because they were cross-sectional studies, commentaries or reviews (n=79). Other reasons for exclusion included not examining SEIS use (n=5), conducted with adults (n=5), conference abstract of published data (n=1), and did not examine association with tobacco/cigarette smoking (n=26) (Figure A4.2). All included studies were undertaken in the United States and quantified participants’ SEIS ever use via a single question. The mean age for two studies was 14 years and the other was 20 years. Study characteristics are reported in Table 2.
20 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. analyses. main Data collection collection Data modality Questionnaire, Questionnaire, pen and paper Questionnaire, pen and paper Questionnaire, Questionnaire, pen and paper not
and Age range Age grades 9–12 grades 9–12 11–14 years (middle schools), 15–18 (high years schools) analyses
48.9% 49% sensitivity Sex (%) Sex F: 50% M: 50% F: 51.1% M: F: M: 51% in
included sample, were selected
cluster names)
Sampling frame Sampling A nationally representative representative nationally A high public sample of Alaska was schools in scientifically A three-stage cluster cluster three-stage A sampling procedure a cross- generate to nationally sectional, sample of representative students in grades 6–12 and the from all states A Columbia. District of stratified oversample designed to and black non-Hispanic was students, Hispanic employed All three high schools All three in north were California included in the study authors’
(first
n 1 418 2 769 18 406; 187 schools (74.8%) Survey name Survey Youth Risk Risk Youth Behaviour Survey High School Questionnaire modelled after the Monitoring Future National Youth Survey Tobacco (NYTS) Year of of Year data collection 2015 2013 2013 Country Country data of collection United United States (Alaska) United United States (California) United States
2014
First author’s last author’s First year name, Alaska Department of Health and Social 2015 Services, (35) Anand, 2015 (28) Anand, Arrazola, (29) Table 1. Study characteristics of all included cross-sectional studies examining prevalence of SEIS use among among use SEIS of prevalence examining studies cross-sectional included all of characteristics Study 1. Table 1) (objective people young 2012 (53) West, and (49) , 2015 Surís, 2016 (52) , Ford, 2015 (50) , Note: Eastwood,
21 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Data collection collection Data modality Questionnaire, Questionnaire, pen and paper Questionnaire, Questionnaire, pen and paper Questionnaire, Questionnaire, pen and paper Questionnaire, pen and paper
Age range Age 11–14 years (middle schools), 15–18 (high years schools) 16–17 years grades 6–12 13–19 years 49.8% 48.8% 49% Sex (%) Sex Not reported F: 50.2% M: F: M: 51% F: 51.2% M:
on were
based 2014 schools five
stratified Arrazola Sampling frame Sampling See A representative sample representative A schools from secondary of was around the country participation for selected and location, school type and location, size used a two- The FYTS probability stage cluster obtain a sample design to public random sample of middle and high schools A cluster probability probability cluster A sample design was used. the districts distribute To evenly, chosen based on their locations geographical
172 n 10 419 middle school students, 11 459 high school students 821 schools 12 615 students from 4 341
16–17- of
Health Youth Survey name Survey National Youth National Youth Survey Tobacco (NYTS) 2014 Perception of of Perception Plain Packaging a nationally Study, representative school-based survey year olds year 2013 Florida Tobacco Youth Survey 2008 Promotion in Fund Project Korea of Republic Year of of Year data collection 2014 2014 2013 2008 Country Country data of collection United United States Ireland United United States (Florida) Republic of of Republic Korea
First author’s last author’s First year name, Arrazola, 2015 Arrazola, (12) Babineau, 2015 Babineau, (24) Barnett, 2015 (30) Barnett, Cho, 2011 (37) Cho,
22 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Questionnaire, Questionnaire, pen and paper Questionnaire, pen and paper Data collection collection Data modality Questionnaire, Questionnaire, pen and paper
11–14 years (middle schools), 15–18 (high years schools) 12–19 years Age range Age Grades 6–12
49.5% 48.9% 49.4% 49.4% F: M: 50.5% M: 50.6% (2012) F: M: 51.1% (2011) F: Sex (%) Sex F: M: 50.6%
188 000 2014 2014 the of Arrazola Arrazola school children of Paris school children of see Sampling frame Sampling Survey was conducted on was conducted Survey students randomly 2% of class and by selected a representative provided sample See
a
24 658 (2012) n 2 519 17 353 (2011), 22 529 (2012) 18 866 (2011), Survey name Survey Annual survey Annual survey by conducted San Tabac Paris National Youth Survey Tobacco (NYTS) National Youth National Youth Survey Tobacco (NYTS) Year of of Year data collection 2012 2012 2011, 2011, 2012 2011, Country Country data of collection France France (Paris) United States United United States
(19) (31)
2014 2014
(45) First author’s last author’s First year name, Dautzenberg, Dautzenberg, 2013 Dutra, Corey,
23 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Web-based Web-based questionnaire Face to face to Face Data collection collection Data modality
11–18 years 11–16 years Age range Age 47.7% 48.9% F: 50% M: 50% Sex (%) Sex (2013) F: 52.3% M: (2014) F: 51.1% M:
b
by
Region 16–18 Office aged stratified
Classification
A Of Residential Of Residential Neighbourhoods (ACORN) and Individuals Using random location quota sampling, participants were drawn from 92 electoral wards across the United Kingdom, Government were sampled directly sampled directly were online from YouGov’s who had people panel of be to consent provided sent and were contacted take an email invitation to Individuals aged 11– part. via an recruited 15 were parents or legal email to YouGov guardians from the them which asked panel, read the information to and then about the survey, to over pass the survey and their their child if they part. take to child agreed were Those giving consent to a link follow to asked online the survey Sampling frame Sampling
2 177 (2013), 2 068 (2014) 1 205 n YouGov YouGov 2013/2014 Tobacco Youth Survey Policy (YTPS) Survey name Survey 2014
2014 Year of of Year data collection 2013, United United Kingdom Country Country data of collection United United Kingdom (England)
Ford, 2016 (52) Ford, First author’s last author’s First year name, Eastwood, 2015 Eastwood, (50)
24 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Questionnaire, Questionnaire, pen and paper Questionnaire, Questionnaire, pen and paper Face to face to Face Data collection collection Data modality Questionnaire, Questionnaire, pen and paper c 15–19 years 15–19 years 15–19 years Age range Age 15 years
54% 45.2% 48.3% 48% 46% 54.8% 51.7% M: 52% M: (2015) F: (2013, (2013, 2014) F: Not reported F: M: Sex (%) Sex F: M:
only
3 000 of excluded ≥ 15 2012;
stratified were aged sample comparison 20 000 Goniewicz, 2014 overall ≤ three-stage
years representative of the of representative years general Italian population and over years aged 15 was surveyed individuals students recruited from 21 students recruited regions schools across two included in were in Poland the cluster sampling cluster whereby procedure, schools and universities as the treated were was used. unit, primary with a population Regions of See An A Sampling frame Sampling A nationwide probability nationwide probability A students. sample of Sampling units were school classes drawn multistage clustered by sampling from probability Education’s of the Ministry Sampling listing. complete was proportional across school types and regions
144 (2014), 1 970 163 (2013), 163 (2013), 153 160 (2015) 13 787 from schools and 32 universities n 1 320
c
Health Unspecified Unspecified Survey name Survey Unspecified 2014 Behaviour in School-aged Children Survey
2014,
2013– 2014 2010– 2011 Year of of Year data collection 2013, 2015 2014 Poland Poland Country Country data of collection Italy Greece
2014
Goniewicz, (11) Goniewicz, 2012 Goniewicz, (41) First author’s last author’s First year name, Fotiou, 2015 (47) Fotiou, Gallus, 2013 (25) Gallus,
25 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Questionnaire, Questionnaire, pen and paper Questionnaire, pen and paper Questionnaire, pen and paper Questionnaire, Questionnaire, pen and paper Data collection collection Data modality
15–16 years 13–15 years 13–18 years grades 9–12 Age range Age 49.2% 48% 50.8% Not reported Not reported F: M: 52% Sex (%) Sex F: M:
9
or 420 42 half
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schools aged 13–15 years from all years aged 13–15 Hungarian schools boards, 671 the sample completed of the e-cig part (grades 9–12) (school, class), two cluster cluster two class), (school, design, Sampling frame Sampling A three-stage random three-stage A used sampling procedure the nationwide secure to students at sample of each the Methods similar to and European MTF survey The Youth School Project. are surveys in Iceland all 10th to administered grade students (ages 15– the by in Iceland years) 16 Social for Centre Icelandic Analysis at and Research University Reykjavik A cluster sample design cluster samples of that produced students Stratified n 41 600 3 477 2 325 (2012); 4 108 (2013) 2 832 Survey name Survey Monitoring the Monitoring Future: national result on survey drug use in Iceland Youth Survey Global Youth Global Youth Survey Tobacco 2013 Ontario Student Drug Use and Health Survey Year of of Year data collection 2014 2015 2012, 2013 2012, 2013 Country Country data of collection United United States Iceland Hungary Canada Canada (Ontario) (42)
First author’s last author’s First year name, Johnston, 2015 Johnston, (32) 2015 Kristjansson, (46) Hungarian Focal Tobacco for Point Control Hamilton, 2015 Hamilton, (44)
26 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Face to face to Face Questionnaire, Questionnaire, pen and paper Data collection collection Data modality Web-based Web-based questionnaire
15–17 years grades 9–12 Age range Age 13–18 years 47.9% 48.2% 52.7% 51.8% 47.3% F: 52.1% M: Sex (%) Sex F: M: F: M:
and high 2014, 2 400 400 In
Māori to stratified,
of and multistage peoples.
middle multistage, stratified
New Zealand 2013 Census 2013 Census Zealand New the mesh blocks (i.e., smallest geographical which the Census units for data are available) were used Sampling frame Sampling Pacific schools in All public Montana with students in grades 9 through 12 were for be selected eligible to inclusion in the sample. schools were Fifty-four with selected randomly proportional to probability enrolment classrooms (secondary classrooms (secondary sampling units) consisting all students in three of the classes from each of 400 and random clustered sampling probability including an method, oversample A schools (primary sampling schools (primary units) from 129 strata A cluster sampling method cluster was The survey was used. administered
but
49 3.8%
4 486 students from n schools (78%) 2 594 only (n=99) were 15–17 years 75 643 Montana Youth Montana Youth Behavioral Risk Factor Survey name Survey Health and Survey Lifestyles (HLS) 2011 Korean 2011 Korean Risk Youth Behaviour Web Survey 2015 Year of of Year data collection 2014 2011 United United States (Montana) Country Country data of collection New Zealand Republic of of Republic Korea
of
(38) Office
(36) 2014
Montana Instruction, Public 2015 First author’s last author’s First year name, Lee, Li, 2015 (26) Li,
27 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Questionnaire, Questionnaire, pen and paper Data collection collection Data modality Questionnaire, pen and paper 13, 15 13, years 10–11 years (CHETS), 11–16 years (HBSC Wales) Age range Age 49.8% 49.9% F: 50% M: 50% Sex (%) Sex (CHETS) F: 50.2% M: (HBSC Wales) F: 50.1% M:
to authority schools.
schools.
local
Scotland. by according in primary 4) 75 secondary and All local authority and All local authority funded independently schools with pupils in the target age groups were inclusion in the eligible for with the exception survey, children schools for of educational with special needs Sampling frame Sampling sampled pupils The survey in high school (years 2 and eligibility for free free for and eligibility school meals All maintained and independent secondary were Wales schools in stratified State-maintained schools State-maintained 6 students were year with stratified school meal free high/low and local entitlement, education authority sampled from Wales HBSC 82 CHETS Wales 2 sampled Wales CHETS from
n 33 685 1 495 (CHETS), 8 950 (HBSC Wales)
Welsh 2014 Scottish Schools Scottish Adolescent and Lifestyle Use Substance (SALSUS) Survey Survey name Survey The Child Exposure to Smoke Tobacco (CHETS) survey undertaken in (CHETS Wales 2) and Wales the Health Behaviour in School-aged Children (HBSC) (HBSC Survey Wales) 2014
Year of of Year data collection 2014 2013, Country Country data of collection United United Kingdom (Wales) United United Kingdom (Scotland)
(40) First author’s last author’s First year name, Moore, 2015 (27) Moore, NHS National Scotland, Services 2014
28 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Questionnaire, Questionnaire, pen and paper Questionnaire, Questionnaire, telephone Data collection collection Data modality Web-based Web-based questionnaire
grades 6–12 15–19 years Age range Age 12–18 years 50.4% 49% 49.6% F: M: 51% F: M: Sex (%) Sex F: 0% M: 100%
who Parents stratified
households
years.
phase, two-phase The sample design is a random sample of random sample of In the numbers. telephone first using are selected In random digit dialling. one or phase, the second none) individuals (or two based upon are selected household composition See Barnett 2015 See Sampling frame Sampling consented in 2010 to Wave Wave in 2010 to consented in recontacted 1 were where their sons 2, Wave participate to invited were A survey company company survey A a national constructed States United panel of using households by sampling. probability company The survey sampled then randomly panel members who were parents with sons aged 11–17
d 2 105 75 428 (2012), 69 923 (2014) n 12 208 (2011), 228
e Florida Canadian Tobacco, Tobacco, Canadian and Alcohol Drugs Survey (CTADS) Survey name Survey Data are from the annual 2011– 2014 Youth Tobacco Tobacco Youth (FYTS) Survey Knowledge Knowledge Networks Panel Knowledge 2014
2013 Year of of Year data collection 2011, 2012, 2012, 2011, 2013, 2011 Canada Country Country data of collection United United States (Florida) United United States
Reid, 2015 (43) Reid, First author’s last author’s First year name, Pepper, 2013 (34) Pepper, Porter, 2015 (33) Porter,
29 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. Face to face to Face Questionnaire, Questionnaire, pen and paper Data collection collection Data modality Web-based questionnaire
f 12–18 years 16–20 years 16.2 years Age range Age 51.4% 49.6% 48.6% 50.4% Not provided Sex (%) Sex F: M: F: M:
1 800
district,
financial
by Classification stratification
A
Baseline surveys Baseline surveys via were conducted cross-sectional monthly household computer- of interviews assisted approximately adults aged 16 and over using random in England, location quota sampling, and by Of Residential Neighbourhoods (ACORN) characteristics mixed/single sex sex mixed/single education, and school type support, Sampling frame Sampling A random sample of 35 random sample of A invited schools were participateto in the [email protected] study subsample A in 2012. from the ado@internet. to consented ch study and were being contacted up in this wave followed School sampling was stratified
f
1 405 (2014), 1 332 (2015) n 621 45 128 Smoking Toolkit Smoking Toolkit Study Survey name Survey Data were drawn Data were from ado@ a internet.ch, longitudinal on Internet study use based on a representative sample of students in the French- speaking part of Switzerland Questionnaire from adapted the Global Youth Survey Tobacco (GYTS) 2015
2014, Year of of Year data collection 2014 2012– 2013 United United Kingdom (England) Country Country data of collection Switzerland China (Hong Spe - Kong cial Admin - istrative Region)
Fidler, 2012; (53, 51) (53,
2011 West, First author’s last author’s First year name, Surís, 2015 (49) Surís, 2015 (17) Wang,
30 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
awareness, Questionnaire, Questionnaire, pen and paper Data collection collection Data modality E-cigarette
al. et S 14–15 years Age range Age 2011;11(1):1–9.
Garattini Health.
P, 49% 49.8% (2012) F: M: 51% (2014) F: M: 50.2% Sex (%) Sex Public areas.
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S, geographical Pichini England.
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R, in small . http://www.cdc.gov/tobacco/data_statistics/surveys/nyts/ of Pacifici
Research. A, cessation from: A two-stage cluster cluster two-stage A obtain a sample design to representative nationally Zealand New sample of 10 students was used year Sampling frame Sampling profiles Lugo
Tobacco S, smoking Available
and lifestyle 2]. and Gallus healthycanadians.gc.ca/science-research-sciences-recherches/data-donnees/ctads-ectad/ http://www.floridahealth.gov/statistics-and-data/survey-data/fl-youth-tobacco-survey/_ 3 127 (2012), 2 919 (2014) n Oct and
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First author’s last author’s First year name, White, 2015 (39) White, summary-sommaire-2013-eng.php A, McEwen Jarvis MJ, O, West Shahab L, Original publication: Fidler JA, author. corresponding by provided this subgroup (unpublished data) were results for Updated f. Stapleton . documents/2011-state/index1.html Government [Internet]. (CTADS). and Drugs Survey Alcohol Tobacco, 2013: Canadian results for of Summary Canada. of Government Data obtained from website. e. of d. Data obtained from website. Florida Health. 2011 Florida Youth Tobacco Survey reports: Fact Sheet 3: Youth smokeless tobacco use. [Internet]. Florida Department [Internet]. use. tobacco smokeless Youth reports: 3: Fact Sheet Survey Tobacco Youth 2011 Florida Florida Health. Data obtained from website. d. of use, c. b. a. Data obtained from website. Centres for Disease Control and Prevention. Smoking and tobacco use: National Youth Tobacco Survey (NYTS). [Internet]. Centres for for Centres [Internet]. (NYTS). Survey Tobacco Youth National use: tobacco and Smoking Prevention. and Control Disease for Centres website. from obtained Data a. Disease
31 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
CI:
1.10– higher
95% CI: and 95% = 0.02). 8.3; 2.73; 95% P 0.001) 2.00–3.73; ≤ odds of using odds of at 12 cigarettes months follow-up (AOR 1.2–58.6) SEIS ever users SEIS ever at baseline had significantly increased odds using any of combustible products tobacco (AOR CI: P (AOR cigarettes 1.75; 2.77; Individuals non- who were susceptible and non-smokers users SEIS ever at baseline had significantly Results Sociodemographic Sociodemographic race, sex, (age, higher parental education), environmental (living factors peer situation, smoking) and intrapersonal factors (mental health, traits, personality psychological associated process) risky with smoking, behaviour and smoking Sociodemographic, Sociodemographic, personal and environmental variables sex, including age, maternal race, education, sensation-seeking parental tendency, smoking and peer smoking Covariates adjusted Covariates Six Six and 12 months 12 months Follow- time up points
Surveys Surveys either in person, telephone or Internet Telephone Telephone survey Data collection modality - - Use of Use of cigarettes and other com bustible nicotine products in the past months six Initiation smok of ing Outcomes
2.4) 14.06 years (95% CI: 14.04– 14.07) 19.5 years (SD 2.0) SEIS for users; 20 years (SD non- for users Age, Age, mean
F: 53.2% M: 46.8% F: 53.9% M: 46.1% Sex (%) Sex Students in high public schools in the Angeles Los metropolitan chosen area, of because their diverse demographic characteristics and proximity Data collected from individuals that had been part a large of nationally representative States United study Sampling Sampling frame
2 502 694 n Longitudinal, Longitudinal, prospective cohort study Longitudinal, prospective cohort study Study design Study (54) (55) Leventhal, Leventhal, United 2015, States Primack, United 2015, States First author’s author’s First name, last country year, data of collection Table 2. Study characteristics of all included studies for objective 2 objective for studies included all of characteristics Study 2. Table
32 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
1.17– CI: < 0.001)
95% P significantly increased odds of increased odds of use at cigarette (AOR follow-up 1.67; 2.39; In an imputed In an imputed ecigarette analysis, users at baseline had Results The multivariable analyses controlled demographics, for parenting and personality variables and for adjusted within clustering schools Covariates adjusted Covariates 12 months Follow- time up points Paper and Paper pencil survey Data collection modality Onset of Onset of smoking Outcomes
0.7) 14.7 years (SD Age, Age, mean 47% F: 53% M: Sex (%) Sex Schools on the island Oahu, of were Hawaii, be to selected representative school of in systems of Six Hawaii. invited seven schools participated and students invited were complete to the survey Sampling Sampling frame 1 302 n Longitudinal, Longitudinal, prospective cohort study Study design Study
Wills, 2016, 2016, Wills, Hawaii, States United (56) First author’s author’s First name, last country year, data of collection
33 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4.2 Risk of bias
4.2.1 Objective 1 Eight of 32 studies satisfied seven of 10 quality assessment criteria, 17 satisfied five or six criteria, and seven satisfied three or four criteria (Figure A4.3). For 22 of the 32 included studies, the study sample was deemed to be representative of the target population. For the majority of these studies, staged cluster sampling and statistical weights were used to ensure the sample was representative of the target population. For the remainder of the studies, sample representativeness was unclear as data weighting was not reported, nor was comparison made between the characteristics of the sample and the target population. Nineteen of the 32 studies described the study setting and the demographics of study subjects in enough detail for comparison to be made to other populations. For all studies apart from four, participant recruitment was rated as appropriate due to random sampling of clusters and participants. In addition, 25 of the 32 studies were deemed to have an adequate sample size. Twenty-two of the 32 studies undertook data weighting to correct for bias due to non-response and ensure sufficient coverage of the sample. For all studies excepted one, the objectivity of the measures was not reported. The reliability of the measures was not reported for all studies. All studies conducted appropriate statistical analysis based on the study aims. The majority (20 of 32) identified and accounted for important confounders and subgroups through regression analysis.
4.2.2 Objective 2 As shown in Figure A4.4, none of the longitudinal studies were classified as having a sample representative of the target population. All three studies described the study setting and the demographics of study subjects in detail. The precision of the prevalence estimates in Primack et al. (55) was limited by the small number of participants who reported SEIS use at baseline (n=16). For all studies it was unclear whether the self- reported methods for collecting data on SEIS use and subgroup characteristics were reliable. Also, while Leventhal et al. (54) reported that all measures used in the study had adequate psychometric properties, the validity of the measures used in Primack et al. (55) and Wills (56) was unclear. All studies conducted appropriate statistical analysis, accounting for important confounders associated with cigarette use, such as sex, age, ethnicity and smoking status of family and friends. Appropriately, all studies also used a multiple imputation approach to address attrition bias and examined association only in young people where tobacco smoking was absent at baseline.
4.3 Overall prevalence of SEIS use among young people (objective 1)
Prevalence of SEIS ever use between 2013 and 2015. The pooled estimate of the prevalence of SEIS ever use from 20 studies conducted between 2013 and 2015 was 16.4% (95% CI: 12.5–20.6%) (Figure A4.5). Among the 14 studies that reported data by sex, the prevalence was 17.4% (95% CI: 10.9–25%) among males and 14.3% (95% CI: 8.7–21%) in females (data not shown). In the sensitivity analyses (Figure A4.6), including
34 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. an additional three studies (49, 50, 52) that did not employ probability sampling (23 studies overall), the prevalence of SEIS ever use was 16.1% (95% CI: 12.6–20.0%) overall, 19.3% (95% CI: 12.5–27.1%) among males (13 studies) and 15.5% (95% CI: 9.9–22.2%) in females (13 studies).
Change in prevalence of ever use between 2008 and 2015. The pooled prevalence of SEIS ever use between 2008 and 2015 by country is shown in Figure A4.7. For four of the five countries where more than one comparable estimate of prevalence was provided over time, prevalence of ever use increased (see Figure A4.7). In the Republic of Korea, prevalence of ever use among 13–19-year-olds increased from 0.5% (95% CI: 0.3–0.8%) in 2008 to 9.4% (95% CI: 9.2–9.6 %) in 2011. In New Zealand, prevalence estimates in 14–15-year-olds increased from 7.0% (95% CI: 6.1–8.0%) to 20.0% (95% CI: 18.6–21.5%) between 2012 and 2014. In Poland, among 15–24-year-olds, prevalence estimates of ever use were 20.9% (95% CI: 20.2–21.6%) in 2010–2011 and 62.1% (95% CI: 59.9–64.2%) in 2013–2014 among 15–19-year-olds. Similarly, in the United States, in nationally representative samples, prevalence of ever use increased from 1.4% (95% CI: 1.2–1.7%) to 3.0% (95% CI: 2.6–3.4%) among middle school children and from 4.7% (95% CI: 4.3–5.1%) to 11.9% (95% CI: 11.3–12.5%) among high school students between 2011 and 2013. Multiple estimates of prevalence over time were also available for Italy, where no difference was observed at the multiple time points (9.2% (95% CI: 5.2–14.7%) in 2013 and 4.4% (95% CI: 1.8–8.8%) in 2015). Different measures however were used for the different data collection years (occasional use in 2014–2015 and ever use for 2013) in Italy.
Prevalence of SEIS current use between 2013 and 2015. The pooled estimate of the prevalence of current SEIS use from 19 studies conducted between 2013 and 2015 was 5.6% (95% CI: 3.4–8.3%) (Figure A4.8). Among the 12 studies that reported data by sex, the prevalence was 6.3% (95% CI: 3.7–9.6%) among males and 4.3% (95% CI: 2.4–6.8%) in females (data not shown). In the sensitivity analyses (Figure A4.9) with an additional five studies (49–52) (24 studies overall), the prevalence of SEIS ever use was 5.5% (95% CI: 3.5–7.9%) overall, 7.4 % (95% CI: 4.5–10.8%) among males (13 studies) and 4.9% (95% CI: 2.8–7.4%) in females (13 studies).
Change in prevalence of current use between 2008 and 2015. The pooled prevalence of current SEIS use between 2008 and 2015 by country is shown in Figure A4.10. In three of the four countries where multiple comparable estimates of prevalence were available over time, prevalence of current use increased. In Poland, data collected on 15–24-year-olds in 2010–2011 reported 8.2% (95% CI: 7.8–8.7%) current use, compared with 29.9% (95% CI: 27.9–32.0%) among adolescents aged 15–19 years in 2013–2014. In the United States, data from the National Youth Tobacco Survey reported that prevalence of current use increased from 0.6% (95% CI: 0.4–0.8%) in 2011 to 3.9% (95% CI: 3.5–4.3%) among middle school students and from 1.5% (95% CI: 1.3–1.8%) to 13.4% (95% CI: 12.8–14.0%) among high school students between 2011 and 2014. In Hungary, however, the prevalence of current use decreased from 13% (95% CI:
35 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
11.6–14.4%) in 2012 to 9.0% (95% CI: 8.1–9.9%) in 2013 among mainly young people aged 13–15 years. No changes were observed in Italy from 1.8% (95% CI: 0.4–5.3%) in 2013 to 1.3% (95% CI: 0.2–4.4%) in 2015 among adolescents aged 16–19 years.
4.4 Prevalence among non-smokers (objective 1)
Prevalence of SEIS ever use between 2013 and 2015. The pooled estimate of the prevalence of SEIS ever use among non-smokers from 13 studies conducted between 2013 and 2015 was 7.0% (95% CI: 5.1–9.3%) (Figure A4.11). In the sensitivity analyses with an additional three studies (40, 50), the prevalence of SEIS ever use from 15 studies overall was 6.4% (95% CI: 4.6–8.5%) (Figure A4.12).
Change in prevalence of ever use between 2008 and 2015. The pooled prevalence of SEIS ever use among non-smokers between 2008 and 2015 by country is shown in Figure A4.13. National survey data of middle and high school students in the United States reported an increase in prevalence of SEIS ever use from 1.8% (95% CI: 1.6–2.0 %) in 2011 and 4.4% (95% CI: 4.1–4.6%) in 2012. There was no change in prevalence of ever use for Italy, where surveys of 16–19-year-olds reported prevalence of ever use of SEIS by non-smokers of 5.1% (95% CI: 2.1–10.3%) in 2013, 0.7% (95% CI: 0.0–3.9%) in 2014, and 1.4% (95% CI: 0.2–5.0%) in 2015.
Prevalence of SEIS current use between 2013 and 2015. The pooled estimate of the prevalence of current use among non-smokers from 11 studies conducted between 2013 and 2015 was 1.5% (95% CI: 0.3–3.5%) (Figure A4.14). In the sensitivity analyses with an additional four studies (40, 50) (15 studies overall), the prevalence of SEIS ever use was 1.3% (95% CI: 0.4–2.8%) (Figure A4.15).
Change in prevalence of current use between 2008 and 2015. The pooled prevalence of current SEIS use among non-smokers between 2008 and 2015 by country is shown in Figure A4.16. Multiple comparable estimates were available from three countries: Italy, Poland and the United States. In the United States, estimates from the state of Florida found prevalence of current use in non-smokers increased from 0.7% (95% CI: 0.5–1.0%) to 2.8% (95% CI: 2.6–3.0%) among middle school students, and from 0.8% (95% CI: 0.6–1.1%) to 6.9% (95% CI: 6.6–7.2%) among high school students between 2011 and 2014. In United States national samples, the prevalence of current SEIS use was 0.6% (95% CI: 0.5–0.7%) for 11–18-year-olds in 2011, and 1.1% (95% CI: 0.9–1.2) in 2012. In Poland, prevalence was 2.4% (95% CI: 2.1–2.7%) in 2010–2011 and 13.0% (95% CI: 11.2–15.0%) in 2013–2014. No changes were observed in Italy (0% (95% CI: 0.0–2.7%) in 2013, 0% (95% CI: 0.0–2.6%) in 2014, and 0% (95% CI: 0.0–2.6%) in 2015.
36 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4.5 Prevalence among current smokers (objective 1)
Prevalence of SEIS ever use between 2013 and 2015. From the 13 studies conducted from 2013, the pooled estimate of SEIS ever use among current tobacco smokers was 54.7% (95% CI: 47.0–62.3%) (Figure A4.17). In the sensitivity analyses with an additional two studies (50) (15 studies overall), the prevalence of SEIS ever use was 53.2% (95% CI: 45.9–60.5%) (Figure A4.18).
Change in prevalence of ever use between 2008 and 2015. The pooled prevalence of SEIS ever use among current-smokers between 2008 and 2015 by country is shown in Figure A4.19. In Italy and the United States, multiple estimates of prevalence of SEIS ever use were provided over time. In the United States, among nationally representative samples of 11–18-year-old students, the prevalence increased from 28.1% (95% CI: 25.0–31.5%) in 2011 to 58.1% (95% CI: 54.8–61.4%) in 2012. In Italy no changes in estimates were observed in 2013 (29.6%; 95% CI: 13.8–50.2%), in 2014 (35.7%; 95% CI: 12.8–64.9%), and in 2015 (26.3%; 95% CI: 9.1–51.2%).
Prevalence of SEIS current use between 2013 and 2015. The pooled estimate of the prevalence of current SEIS use among current tobacco smokers from the 10 studies conducted from 2013 was 19.4% (95% CI: 8.3–33.5%) (Figure A4.20). In the sensitivity analyses with an additional two studies (50) (14 studies overall), the prevalence of SEIS ever use was 17.8% (95% CI: 8.8–28.9%) (Figure A4.21).
Change in the prevalence of current SEIS use between 2008 and 2015. The pooled prevalence of current SEIS use among current smokers between 2008 and 2015 by country is shown in Figure A4.22. For Poland and the United States, multiple comparable estimates of prevalence available across time showed an increase in current use of SEIS among smokers. In Poland, current use in adolescents increased from 15.3% (95% CI: 14.3–16.4%) in 2010–2011 to 57.4% (95% CI: 53.8–61.0%) in 2013–2014. In the United States, among nationally representative samples of 11–18-year-olds, the prevalence increased from 9.8% (95% CI: 7.8–12.1%) in 2011 to 26.5% (95% CI: 23.6–29.5%) in 2012. No changes in prevalence were observed in Italy between 2013 (11.1%; 95% CI: 2.4–29.2%), 2014 (7.1%; 95% CI: 0.2–33.9%) and 2015 (5.3%; 95% CI: 0.1–26.0%).
4.6 Exploring heterogeneity (for objective 1) To explore reasons for the high observed heterogeneity (> 90%) in the pooled estimates of prevalence (between 2008 and 2015), a meta-regression including year of study, age range, regulation, sex and MPOWER score was undertaken for SEIS ever and current use. For prevalence of ever use, the multivariable model including all five covariates accounted for 44% of the observed heterogeneity, where age range (P < 0.05), regulation (P < 0.05) and year of data collection (P < 0.001) were significant. For current SEIS use, year of data collection (P < 0.05) and MPOWER score (P < 0.05) were significant, with the multivariable model including all five covariates accounting for 24% of the identified heterogeneity.
37 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Among non-smokers and current smokers, sex was not included in meta-regression modelling due to lack of available data. For ever use among non-smokers, none of the variables were significantly associated with prevalence heterogeneity. For current SEIS use among non-smokers, year (P < 0.05), age (P < 0.05) and MPOWER score (P < 0.05) were significantly associated with prevalence heterogeneity and accounted for 40% of the identified heterogeneity.
Among current smokers, year (P < 0.05) and regulation (P < 0.05) were significantly associated with the heterogeneity observed in prevalence ever use, and the multivariable model including regulation, year and age accounted for the largest amount (52%) of heterogeneity. For current SEIS use among smokers, only MPOWER score was significant (P < 0.01), and the multivariable model including all four covariates (year, age, regulation and MPOWER score) explained 24% of the observed heterogeneity.
4.7 Objective 2 Three studies (54–56) conducted in the United States were included (see Table 2 for study characteristics). Leventhal and colleagues undertook a prospective longitudinal cohort study with 2530 14-year-old English-speaking adolescents, recruited from 10 demographically diverse schools in Los Angeles, who had never used any combustible tobacco products (54). In a repeated measure using generalized mixed model analysis, including only non-tobacco users and adjusting for school, time (six and 12 months) and other potential demographic, environmental and personal covariates, those students who had ever used SEIS at baseline were significantly more likely to report using at least one puff of combustible tobacco products (described as use of a few puffs in the past six months) at 12 months follow-up (OR 2.73; 95% CI: 2.00–3.73; P ≤ 0.001). This association was significant across the examined tobacco products: cigarettes (OR 1.75; 95% CI: 1.10–2.77, P = 0.02), cigars (OR 2.96; 95% CI: 2.00–4.38; P ≤ 0.001) and hookah (OR 2.26; 95% CI: 1.56–3.29; P ≤ 0.001).
Primack and colleagues (55) examined, in a national sample of individuals aged 16–26 years (mean age 19.5 years for SEIS users and 20 years for non-SEIS users), whether being a non-susceptible non-smoker (defined as those reporting that they definitely would not accept a cigarette from a friend and definitely would not smoke in the next year) who used SEIS at baseline (2012/2013) predicted higher experimentation of tobacco cigarette smoking at 12 months follow-up (2013/2014) (55). In the primary analyses imputing for missing data (n=694), a multivariable multinomial logistic regression adjusting for sex, age, race, education level and sensation-seeking tendency found that individuals who smoked SEIS at baseline had significantly higher odds (AOR 8.3; 95% CI: 1.2–58.6%) of progressing from non-susceptible non-smoker to tobacco cigarette smoking one year post baseline. This finding was consistent across multiple sensitivity analyses undertaken by the authors.
Wills and colleagues (56) undertook a school-based survey with 9th and 10th grade students in Hawaii, United States, to examine whether, among never smokers, those
38 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. who had used e-cigarettes were more likely to have smoked cigarettes at 12-month follow-up. In the adjusted analysis imputing for missing data, individuals who were e-cigarette users at the first time point had an increased odds (AOR 1.67; 95% CI: 1.17–2.39) of smoking at follow-up.
Pooled analysis of the three studies indicated that SEIS smokers at baseline had an increased adjusted odds ratio (AOR 2.19; 95% CI: 1.46–3.3%; I2 = 59.7%) of being a tobacco cigarette user at follow-up (Figure A4.23).
39 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
5. Discussion and conclusion
5.1 Discussion This review aimed to describe the prevalence and trends of SEIS use by young people aged between 10 and 20 years; and to examine the association between SEIS use and initiation of tobacco smoking in this group. To describe prevalence and trends, 28 eligible studies of SEIS use among youths that utilized probability sampling were identified. Three longitudinal studies were identified that examined associations between SEIS use and initiation of tobacco smoking.
The prevalence of SEIS use varied considerably within and between countries. Most recent estimates (2013 and 2015) show ever use of SEIS among non-smokers of 7% and prevalence of current use of less than 3%. Among smokers, in countries including Canada, Ireland, New Zealand, the United Kingdom and the United States, more than 50% of smokers had ever used SEIS, while in Poland, the Republic of Korea and the United States, over 20% were current users. Use of SEIS among smokers and non-smokers was reportedly increasing in Poland and in the United States but not for countries such as Italy, where current SEIS use remained relatively stable. In the sensitivity analyses, small increases in prevalence of SEIS current use among smokers and non-smokers were observed.
Observed differences between countries in prevalence and trends could potentially be attributed to differences in regulation governing the promotion of SEIS and their sale to young people. For example, the authors of the Polish studies suggested that the greater increase in SEIS use among Polish adolescents may be due to availability of SEIS in the market, more aggressive marketing of SEIS, and lower levels of regulation (11). The increase in SEIS use has also coincided with reduced prevalence of current tobacco use globally (12, 57). This has led to suggestions that smokers who have quit smoking may potentially be substituting tobacco smoking with SEIS. This review however found that a large proportion of young smokers were current SEIS users, suggesting that smokers may continue to use SEIS concurrently with traditional cigarettes. Findings from the meta-regression suggest that a number of factors, including MPOWER scores, time (year) and participant age, may be associated with prevalence heterogeneity of current/
40 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ever e-cigarette use. These findings however need to be interpreted with caution, as there is likely to be other unmeasured confounders that have not been considered in this analysis. Further longitudinal research assessing the potential impact of MPOWER scores or policy regulation on SEIS use is probably needed to ascertain the impact of such strategies on prevalence of use in youths.
Pooled data from three longitudinal studies (54, 55) found that the use of SEIS by non- smokers more than doubled the odds of experimentation with tobacco smoking within 12 months. Although a number of design limitations exist, these findings support evidence from previous cross-sectional studies and provide early evidence of a positive association between SEIS use and intentions to try tobacco smoking (17–19). The specific pathway by which SEIS use could lead to uptake of tobacco products is unknown. However, the enjoyment of the sensory tobacco-related cues associated with SEIS use (e.g. inhalation, exhalation) (58), the pharmacological effects of consuming nicotine, and the biological and environmental vulnerability during youth and adolescence have been hypothesized to contribute to an increased inclination of SEIS users to try other nicotine-providing tobacco products (59). Further, other researchers suggest that SEIS may act as catalyst, both in supporting initial initiation of SEIS use and facilitating transition to cigarette uptake (16).
These findings need to be interpreted in light of the limitations of this review. First, all included studies utilized self-reported measures of SEIS use. To our knowledge, the validity of such assessment methods has not been established. Measures such as ever use and use in last 30 days may not provide an appropriate indication of established use behaviours (60). Second, for assessment of current use, this review pooled a variety of measures, primarily “regular use” and “use in the last 30 days”, which may have influenced prevalence estimates for some countries. Third, this study also examined tobacco use among non-smokers rather than never smokers. While it is likely that individuals with previous nicotine dependence may have been included, estimates of tobacco use among youths indicates that the majority of non-smoking youths (> 80%) have never smoked (27, 61). Further, there was considerable variability in the definition of smokers in the included studies, which may have resulted in experimenters being classed as current smokers. Fourth, considerable and statistically significant heterogeneity was found among all pooled estimates presented in the review. For prevalence heterogeneity, the I2 exceeded 70% for each case. None of the covariates examined in the meta-regression significantly accounted for the statistical heterogeneity observed in the meta-analyses of current SEIS use, suggesting that other personal or environmental factors may need to be considered. Finally, only three longitudinal studies were identified to examine associations between SEIS use by non-smokers and later initiation of tobacco. Further research is required to substantiate the findings of such studies.
41 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
5.2 Conclusion Despite SEIS use among non-smoking young people remaining relatively low in most jurisdictions, the finding of a small but significant longitudinal association between SEIS use and tobacco use and of increasing prevalence of SEIS use among non-smoking young people in some countries supports the need for strategies to discourage SEIS use among non-smokers.
42 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
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49. Surís J-C, Berchtold A, Akre C. Reasons to use e-cigarettes and associations with other substances among adolescents in Switzerland. Drug and Alcohol Dependence. 2015;153:140–4.
50. Eastwood B, Dockrell MJ, Arnott D, Britton J, Cheeseman H, Jarvis MJ et al. Electronic cigarette use in young people in Great Britain 2013–2014. Public Health. 2015;129:1150–6.
51. Fidler JA, Shahab L, West O, Jarvis MJ, McEwen A, Stapleton JA et al. “The smoking toolkit study”: a national study of smoking and smoking cessation in England. BMC Public Health. 2011;11(1):1–9.
52. Ford A, MacKintosh AM, Bauld L, Moodie C, Hastings G. Adolescents’ responses to the promotion and flavouring of e-cigarettes. International Journal of Public Health. 2016;61(2):215–24.
53. West R, Owen L. Estimates of 52-week continuous abstinence rates following selected smoking cessation interventions in England, 2012 (http://www.smokinginengland.info/reports/).
54. Leventhal AM, Strong DR, Kirkpatrick MG et al. Association of electronic cigarette use with initiation of combustible tobacco product smoking in early adolescence. Journal of the American Medical Association. 2015;314(7):700–7.
55. Primack BA, Soneji S, Stoolmiller M, Fine MJ, Sargent J. Initiation of cigarette smoking after electronic cigarette use: a national study of young adults. Journal of General Internal Medicine. 2015;30:S193.
56. Wills TA, Knight R, Sargent JD, Gibbons FX, Pagano I, Williams RJ. Longitudinal study of e-cigarette use and onset of cigarette smoking among high school students in Hawaii. Tobacco Control. 2016. doi:10.1136/tobaccocontrol-2015-052705. [Epub ahead of print].
57. WHO global report on trends in prevalence of tobacco smoking, 2015. Geneva: World Health Organization; 2015.
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58. Rees VW, Kreslake JM, Wayne GF, O Connor RJ, Cummings KM, Connolly GN. Role of cigarette sensory cues in modifying puffing topography. Drug and Alcohol Dependence. 2012;124(1–2):1–10.
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48 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 1: Search terms employed in the electronic databases
CINAHL # Searches
S1 e-cig* S2 electr* cig* S3 (MH “Electronic Cigarettes”) S4 vaping S5 “electronic nicotine” S6 e-hookah* S7 electronic hookah* S8 e-nicotine S9 S1 OR S2 OR S3 OR S4 OR S5 OR S6 OR S7 OR S8
COCHRANE LIBRARY # Searches 1 MeSH descriptor: [Electronic Cigarettes] this term only 2 e-cig*.mp 3 electr* cig*.mp 4 vaping.mp 5 electronic nicotine.mp 6 e-hookah*.mp 7 electronic hookah*.mp 8 e-nicotine.mp 9 {or #1-#8}
49 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Database(s): Embase 1974 to 2015 Week 31 # Searches 1 w-cig*.mp. 2 electr* cig*.mp. 3 vaping.mp. 4 electronic nicotine.mp. 5 e-hookah*.mp. 6 electronic hookah*.mp. 7 e-nicotine.mp. 8 electronic cigarette/ 9 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
Database(s): MEDLINE 1946 to Present with Daily Update # Searches 1 e-cig*.mp. 2 electr* cig.mp. 3 Electronic Cigarettes/ 4 vaping.mp. 5 electronic nicotine.mp. 6 e-hookah*.mp. 7 electronic hookah*.mp. 8 e-nicotine.mp. 9 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
50 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Database(s): MEDLINE In-Process & Other Non-Indexed Citations # Searches 1 e-cig*.mp. 2 electr* cig*.mp. 3 vaping.mp. 4 electronic nicotine.mp. 5 e-hookah*.mp. 6 electronic hookah*.mp. 7 e-nicotine.mp. 8 electronic cigarette/ 9 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
Database(s): PsycINFO 1806 to July Week 3 2015 # Searches 1 w-cig*.mp. 2 electr* cig*.mp. 3 vaping.mp. 4 electronic nicotine.mp. 5 e-hookah*.mp. 6 electronic hookah*.mp. 7 e-nicotine.mp. 8 1 or 2 or 3 or 4 or 5 or 6 or 7
51 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 2: Data extraction form (adapted from Cochrane data collection form for intervention reviews)
Citations Author’s name, publication year
Study design Country of study Year of Data Collection Type of study Aims Survey name/ database Sample (n) Approached Eligible Consent Analysed Sampling frame, recruitment method (including sampling unit) Participants Inclusion criteria Exclusion criteria Sex (%) Age, mean (SD), range Age range Race/ethnicity Socioeconomic status Other relevant sociodemographic Subgroups analysed by Data collection Data collection modality Measure used Measures Outcomes (e.g. ever used, current use) e-cigarette type (if specified) Total (Final sample) n Prevalence Upper 95% CI Lower 95% CI
52 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Male (Final sample) n Prevalence Upper 95% CI Lower 95% CI Female (Final sample) n Prevalence Upper 95% CI Lower 95% CI Other Other results Analysis and statistical adjustments Notes
53 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 3: Definition of e-cigarette or SEIS use within included studies
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Alaska Department Youth Risk Behaviour Percentage of Percentage of students of Health and Social Survey students who ever who currently used Services used electronic vapor electronic vapor 2015 Alaska Youth products (e-cigarettes, products (e-cigarettes, Risk Behavior Survey e-cigars, e-pipes, vape e-cigars, e-pipes, vape Results pipes, vaping pens, pipes, vaping pens, e-hookahs, and hookah e-hookahs, and hookah pens such as blu, NJOY, pens such as blu, NJOY, or Starbuzz) or Starbuzz on at least 1 day during the 30 days before the survey) Anand 2015 47-item “High School Have you ever used an When was the last E-cigarette use and Questionnaire” 2013 e-cigarette? time you used an beliefs among urban modelled after • Yes e-cigarette? Monitoring the Future public high school • No • Have never used students in North with additional an e-cigarette information Carolina • Today Arrazola 2014 2013 National Youth Ever use of electronic Current use of Tobacco Use Among Tobacco Survey (NYTS) cigarettes was electronic cigarettes Middle and High determined by was determined by School Students US asking, “Which of the asking, “During the 2013 following tobacco past 30 days, which of products have you the following products ever tried, even have you used on just one time: bidis, at least 1 day- bidis, kreteks, hookah, snus, kreteks, hookah, snus, dissolvable tobacco, dissolvable tobacco, and electronic and electronic cigarettes?” cigarettes?” Arrazola 2015 2014 National Youth Not reported During the past 30 Tobacco Use Among Tobacco Survey (NYTS) days, on how many Middle and High days did you use School Students US e-cigarettes such 2011-2014 as Blu, 21st Century Smoke, or NJOY?
54 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Babineau 2015 2014 Youth Perception Respondents who Respondents who Electronic cigarette of Plain Packaging selected one of the selected one of the use among Irish youth: Study, a nationally following as statement following as statement a cross sectional study representative school- that best describes that best describes of prevalence and based survey of 16-17 them: them: associated factors year olds • I have tried an • I smoke an e-cigarette once or e-cigarette at least twice but don’t use once a month one regularly • I smoke an • I used to smoke e-cigarette at least e-cigarettes but have once a week given up • I smoke an e-cigarette every day. Barnett 2015 2013 Florida Youth Have you ever tried, During the past 30 Adolescent electronic Tobacco Survey even once, electronic days, have you used an cigarette use cigarette? electronic cigarette? associations with • Yes • Yes conventional cigarette • No • No and hookah smoking Cho 2011 2008 Health Have you ever smoked Not reported Electronic Cigarette Promotion Fund a cigarette, even one smoking experience Project in Korea or two puffs? among adolescents • Yes • No Corey 2014 Data are from the see Arrazola 2014 see Arrazola 2014 Electronic cigarette annual 2011-2012 use among middle and National Youth high school students - Tobacco Survey (NYTS) United States, 2011- 2012 Dautzenberg 2013 2012 annual survey Have you ever used an Not assessed E-cig : a new tobacco conducted by Paris San e-cigarette? product for school Tabac. • Yes children in Paris • No Dutra 2014 National Youth see Arrazola 2014 see Arrazola 2014 Electronic cigarettes Tobacco Survey (NYTS) and conventional cigarette use among U.S. adolescents: a cross-sectional study
55 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Eastwood 2015 YouGov 2013/2014 You said that you have Those who had heard Electronic cigarette tried an e-cigarette… of e-cigarettes were use in young people in Which ONE of the then asked to describe Great Britain 2013– following BEST applies their experience of 2014 to you? e-cigarettes with options range from • I tried smoking a ‘never use’ to ‘more real cigarette before than once a week’. The I first tried using an following responses e-cigarette were categorised as • I tried using an ‘monthly or more e-cigarette before I users’: first tried smoking a • I use them real cigarette sometimes (more than • I have never once a month) smoked a real • I use them often cigarette but have (more than once a tried an e-cigarette week) • I don’t remember Fidler 2011 The Smoking Toolkit Study Not assessed Other than yourself, smoking toolkit study’: does anyone regularly a national study of smoke cigarettes or smoking and smoking use an e-cigarette in cessation in England your presence, such as at your home, work, car or other places that you visit regularly? • Yes – cigarettes only • Yes – e-cigarettes only • Yes – both cigarettes and e-cigarettes • No – neither cigarettes nor e-cigarettes
56 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Ford 2016 Youth Tobacco Policy Ever smokers included Not assessed Adolescents’ responses Survey (YTPS) those who indicated to the promotion being regular smokers and flavouring of (at least one cigarette e-cigarettes a week), occasional smokers (less than one a week), those who used to smoke and those who had tried smoking only once. Which of these best describes whether or not you have ever used or tried e-cigarettes? • I have never used e-cigarettes • I have only ever tried e-cigarettes once or twice • I have used e-cigarettes in the past, but I never use them now • I occasionally use e-cigarettes (less than once a month) • I use e-cigarettes at least once a month • I use e-cigarettes at least once a week Fotiou 2015 2014 Health Behaviour Have you ever used an Have you ever used an Prevalence and in School-aged electronic cigarette? electronic cigarette? correlates of electronic Children Survey (HSBC) • Never • Never cigarette use among • Yes • Yes adolescents in Greece: • Only 1-2 times • Only 1-2 times a preliminary cross- sectional analysis of • Yes more than • Yes more than nationwide survey data twice twice • Yes more than • Yes more than twice and I use it now twice and I use it now
57 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Gallus 2014 Structured Have you ever heard Do you use, E-Cigarette questionnaire in the about e-cigarettes, occasionally or Awareness, Use, and context of a computer have you ever tried regularly, the Harm Perceptions assisted personal them or do you have e-cigarette? in Italy: A National in-house interview in the intention to try • Yes, 2013-2015. them? Representative Survey occasionally • I heard about Additional analyses • Yes, regularly from author e-cigarettes and I tried them. • I used it in the past Participants reporting • No they “have heard Those who responded about e-cigarettes and yes regularly were have tried them” were classed as current labelled as “ever users” users of e-cigarettes. Goniewicz 2012 The data was collected Have you ever Have you used an Electronic Cigarette as part of a national heard about e-cigarette at least Use Among Teenagers survey on water pipe electronic cigarettes once in the previous and Young Adults in smoking in 2010- (e-cigarettes)? 30 days? Poland 2011, and 2013-2014. • Yes • Yes Name of survey was • No • No unspecified. Have you ever used an e-cigarette? • Yes • No Goniewicz 2014 The 2012 and 2011 Students were asked Students were asked Rise in Electronic data was subsample whether they had ever whether they had Cigarette Use Among of 2 of the regions smoked or puffed on currently (in the past Adolescents in Poland included as part of e-cigarettes (even a 30 days) smoked or a national survey on single puff). puffed on e-cigarettes water pipe smoking. (even a single puff). Name of survey was unspecified. Data for 2013-2014 were collected from the same 2 regions.
58 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Hamilton 2015 2013 Ontario Student Have you ever smoked Not assessed Waterpipe use among Drug Use and Health at least one puff high school students in Survey from an electronic Ontario: Demographic cigarette? and substance use • Smoking an correlates e-cigarette with nicotine • Smoking an e-cigarette without nicotine • Never smoked but have heard of e-cigarettes • Never heard of e-cigarettes Hungarian Focal Point Global Youth Tobacco Not assessed Those who smoked for Tobacco Control. Survey e-cigarette during the Hungarian and Foreign past 30 days Data & Statistics: Global Youth Tobacco Survey Johnston 2014 Monitoring the future: Not reported Prevalence of use in Key Findings on National survey 2014 the prior 30 days. Adolescent Drug Use result on drug use Kristjansson 2015 Youth in Iceland Not reported Not assessed E-cigarette use and Survey relations to tobacco and alcohol use among adolescents Lee 2014 2011 Korean Youth Have you ever used an Have you used Electronic Cigarette Risk Behaviour Web- e-cigarette? e-cigarettes in the past Use Among Korean Survey • Yes 30 days? Adolescents: A Cross- • No • Yes Sectional Study of • No Market Penetration, Dual Use, and Relationship to Quit Attempts and Former Smoking
59 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Li 2015 2014 Health and Have you ever tried an Which best describes The prevalence, Lifestyles Survey (HLS) electronic cigarette? how often you use an correlates and reasons • Yes electronic cigarette now? for using electronic • No cigarettes among New • At least once a day Zealand adults • At least once a week • At least once a month • Less often than once a month • Do not use one now Current use was defined as at least once a month. Montana Office of Montana Youth Electronic vapor Electronic vapor Public Instruction Behavioural Risk products, such as blu, products, such as blu, 2015 Montana Youth Factor NJOY, or Starbuzz, NJOY, or Starbuzz, Risk Behaviour Survey include e-cigarettes, include e-cigarettes, High School Results e-cigars, e-pipes, vape e-cigars, e-pipes, vape pipes, vaping pens, pipes, vaping pens, e-hookahs, and hookah e-hookahs, and hookah pens. pens. Have you ever used During the past 30 an electronic vapor days, on how many product? days did you use • Yes an electronic vapor product? • No • 0 days • 1 or 2 days • 3 to 5 days • 6 to 9 days • 10 to 19 days • 20 to 29 days • All 30 days
60 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Moore 2015 Data from two data In CHETS Wales 2, Those who selected Electronic-cigarette sets: the CHild children were asked using cigarettes at use among young Exposure to Tobacco if they had ever used least once a month people in Wales: Smoke (CHETS) survey an e-cigarette, with were classed as evidence from two undertaken in Wales response options of: regular users cross-sectional surveys (‘CHETS Wales 2’) in • ‘no’; ‘yes, once’; or 2014; and 2014 Welsh • ‘yes more than Health Behaviour in once’. School-aged Children (HBSC) Survey (‘HBSC In HBSC Wales, young Wales’). people were asked if they had ever used an e-cigarette, with at least once a month response options of: ‘I have never used or tried e-cigarettes’; ‘I have used e-cigarettes on a few occasions (1–5 times)’; or ‘I regularly use e-cigarettes (at least once a month)’ National Services 2013/2014 Scottish An electronic cigarette An electronic cigarette Scotland 2014 Scottish Schools Adolescent (sometimes called an (sometimes called an Schools Adolescent Lifestyle and ‘e-cigarette’) is a tube ‘e-cigarette’) is a tube Lifestyle and Substance Use Survey that can look like a that can look like a Substance Use Survey (SALSUS) normal cigarette, can normal cigarette, can (SALSUS): SMOKING have a glowing tip have a glowing tip Among 13 and 15 year and puffs a vapour and puffs a vapour olds in Scotland 2013 that looks like smoke that looks like smoke but unlike normal but unlike normal cigarettes, they don’t cigarettes, they don’t burn tobacco. Now burn tobacco. Now read the following read the following statements carefully statements carefully and cross the box next and cross the box next to the ONE which best to the ONE which best describes you describes you • I have never used • I use e-cigarettes an e-cigarette sometimes, but no • I used to use more than once a e-cigarettes but don’t month use them anymore • I use e-cigarettes • I have tried an more than once a e-cigarette once month, but less than once a week • I have tried e-cigarettes a few • I use e-cigarettes times once a week or more
61 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Ever e-cigarettes user Current e-cigarettes Database measure user measure Pepper 2013 Knowledge Networks’ Have you ever used an Not assessed Adolescent males’ Knowledge Panel e-cigarette? awareness of and • Yes willingness to try • No electronic cigarettes Porter 2015 Data are from the Have you ever tried During the past 30 Electronic cigarette annual 2011–2014 once using electronic days have you used an and traditional Florida Youth Tobacco cigarettes? electronic cigarette? cigarette use among Survey (FYTS) • Yes • Yes middle and high • No • No school students in Florida, 2011-2014 Reid 2015 2015 Canadian Have you ever tried an In the past 30 days did Tobacco Use in Canada: Tobacco, Alcohol and electronic cigarette, you use an electronic Patterns and Trends, Drugs Survey (CTADS) also known as an cigarette, also known 2015 Edition. e-cigarette? as an e-cigarette? • Yes • Yes • No • No Surís 2015 Data were drawn from Have you ever tried Have you ever tried Reasons to use ado @ internet.ch, a electronic cigarettes? electronic cigarettes? e-cigarettes and longitudinal study on • Never • Never Internet use based associations with • Only once • Only once other substances on a representative • Several times • Several times among adolescents in sample of students in Switzerland the French- speaking • Regularly • Regularly part of Switzerland. Those who Those who selected selected ‘only once’ ‘several times’ and were classed as ‘regularly’ were classed experimenters. as users. Wang 2015 A 2012-2013, Not assessed Only one questions on Electronic cigarette anonymous, self- e-cigarettes use in the use and its association administered past 30 days (yes vs with smoking in questionnaire in no) was used. No levels Hong Kong Chinese Chinese adapted of use were specified adolescents from the Global and students were Youth Tobacco Survey expected to report any (GYTS) (The GTSS use including even 1 Collaborative Group, puff. 2006) White 2015 2012 & 2014 The Have you ever tried Not assessed Tripling Use of Youth Insights Survey electronic cigarettes? Electronic Cigarettes • Yes Among New Zealand • No Adolescents Between 2012 and 2014
62 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 4: List of Figures
Figure 1:Figure PRISMA 1: PRISMA diagram diagram outlining outlining study selectionstudy selection for for prevalenceprevalence of e-cigarette of e-cigarette use (Objective use (Objective 1) 1)
Records identified through Additional records identified database searching through other sources (n = 3547 ) (n = 35) Identification
Records after duplicates removed (n = 2281)
Screening Records screened Records excluded (n = 2281) (n = 2146)
Full-text articles Full-text articles excluded, assessed for eligibility with reasons (n = 135) (n = 107)
Eligibility Adults (n=55) Did not report on Studies included in prevalence of e-cigarette qualitative synthesis use (n=4) (n = 28) Did not use probability sampling (n=4) Not representativie of the region (n=14) Studies included in Not an empirical study Included quantitative synthesis (n=12) (meta-analysis) Included findings (n = 28) previously reported in other published papers (n=18)
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for From: S Moherystematic D, Liberati Reviews A, Tetzlaff and J,M Altmaneta-Analyses: DG, The PRISMA The PRISMA Group (2009) Statement.. Preferred PLoS Reporting Med I6(6):tems fore1000097. Systematic doi:10.1371/ Reviews and Meta- Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097 journal.pmed1000097 For more information, visit www.prisma-statement.org. For more information, visit www.prisma-statement.org.
63 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 2: PRISMA diagram outlining study selection for associationFigure of e-cigarette 2: PRISMA use diagram and tobacco outlining uptake study selection(Objective for 2) association of e-cigarette use and tobacco uptake (Objective 2)
Records identified through Additional records identified database searching through other sources (n = 3547 ) (n = 35) Identification
Records after duplicates removed (n = 2281)
Screening Records screened Records excluded (n = 2281) (n = 2162)
Full-text articles Full-text articles excluded, assessed for eligibility with reasons (n = 119) (n = 116)
Eligibility Did not examine e-cigarette use (n=5) Studies included in Not undertaken in qualitative synthesis youth/adolescents (n=5) (n = 3 ) Did not examine association with tobacco/cigarette smoking (n=26) Studies included in Conference abstract of Included quantitative synthesis published study (n=1) (meta-analysis) Not relevant study design (n = 3 ) (n=79)
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta- Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
From: Moher D, Liberati A,For Tetzlaff more information,J, Altman DG, visit The www.prisma PRISMA- statement.orgGroup (2009).. Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/ journal.pmed1000097 For more information, visit www.prisma-statement.org.
64 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 3: Quality assessment for individual cross-sectional studies included for Objective 1
Yes No Unsure
*Eastwood 2014, Ford 2015, Suris 2015, West 2012 were included in the sensitivity analyses.
65 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 4: Quality assessment for individual longitudinal studies included for Objective 2
Yes No Unsure Figure 5: Pooled analysis of ever e-cigarette use among youth from 2013-2015 from youth among use e-cigarette ever of analysis Pooled 5: Figure
66 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 19.8 (19.2, 20.4) 19.8 (19.2, 20.4) 9.2 (5.2, 14.7) 9.2 (5.2, 14.7) 15.2 (13.9, 16.6) 15.2 (13.9, 16.6) 8.7 (8.2, 9.2) 8.7 (8.2, 9.2) 3.0 (2.6, 3.4) 3.0 (2.6, 3.4) 11.9 (11.3, 12.5) 11.9 (11.3, 12.5) 62.1 (59.9, 64.2) 62.1 (59.9, 64.2) 10.9 (10.5, 11.2) 10.9 (10.5, 11.2) 16.6 (14.6, 18.7) 16.6 (14.6, 18.7) 23.9 (21.0, 26.9) 23.9 (21.0, 26.9) 4.6 (1.9, 9.2) 4.6 (1.9, 9.2) 20.0 (18.6, 21.5) 20.0 (18.6, 21.5) 20.2 (12.8, 29.5) 20.2 (12.8, 29.5) 5.4 (4.4, 6.7) 5.4 (4.4, 6.7) 11.2 (10.6, 11.9) 11.2 (10.6, 11.9) 8.5 (8.2, 8.8) 8.5 (8.2, 8.8) 20.5 (20.1, 20.9) 20.5 (20.1, 20.9) 14.6 (13.3, 15.9) 14.6 (13.3, 15.9) 16.9 (15.7, 18.2) 16.9 (15.7, 18.2) 4.4 (1.8, 8.8) 4.4 (1.8, 8.8) 36.1 (33.6, 38.7) 36.1 (33.6, 38.7) 51.1 (49.6, 52.6) 51.1 (49.6, 52.6) 16.4 (12.5, 20.6) 16.4 (12.5, 20.6) 80 60
40 30 20 10
0 Outcome (n) 3284 15 421 1098 243 1213 1223 3487 219 196 7 584 20 87 1018 3143 6749 422 587 7 512 2292 N 16586 163 2769 12615 8111 10190 1970 32051 1320 821 153 2919 99 1601 9055 36979 32921 2892 3477 160 1418 4486 Age range 15-19 16-19 15-18 11-18 11-14 15-18 15-19 13-15 15 16-17 16-19 14-15 15-17 10-11 11-16 11-14 15-18 14-18 15-16 16-19 14-18 14-18 Data collection 2013 2013 2013 2013 2013 2013 2013-2014 2013-2014 2014 2014 2014 2014 2014 2014 2014 2014 2014 2015 2015 2015 2015 2015 Country Canada Italy US (California) US (Florida) US NYTS US NYTS Poland UK (Scotland) Greece Ireland Italy New Zealand New Zealand UK (Wales) UK (Wales) US (Florida) US (Florida) Canada (Ontario) Iceland Italy US (Alaska) US (Montana) Figure 5: Pooled analysis of ever e-cigarette use among youth from 2013-2015 from youth among use e-cigarette ever of analysis Pooled 5: Figure
Author 67 PrevalenceReid Gallus ofAnand smoking-proxyBarnett Arrazola Arrazola electronicGoniewicz SALSUS inhalingFotiou Babineau systemGallus (SEIS)White useLi andMoore its associationMoore Porter Porter with Hamilton tobaccoKristjansson initiationGallus Alaska in youths:Montana Overall (I^2 = 99.8%, p 0.0) a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Data Age Outcome Author Country collection range N (n) ES (95% CI) % % Weight Weight 3.92 3.92 3.60 3.60 3.90 3.90 3.90 3.90 3.92 3.92 3.92 3.92 3.92 3.92 3.90 3.90 3.92 3.92 3.88 3.88 3.86 3.86 3.58 3.58 3.91 3.91 3.41 3.41 3.90 3.90 3.89 3.89 3.92 3.92 3.92 3.92 3.92 3.92 3.91 3.91 3.91 3.91 3.59 3.59 3.83 3.83 3.88 3.88 3.88 3.88 3.91 3.91 100.00 100.00 Canada Reid Canada 2013 15-19 16586 3284 19.8 (19.2, 20.4)
Canada (Ontario) Hamilton Canada (Ontario) 2015 14-18 2892 422 14.6 (13.3, 15.9)
France Dautzenberg France (Paris) 2012 12-19 3409 277 8.1 (7.2, 9.1) ES (95% CI) ES (95% CI) 19.8 (19.2, 20.4) 19.8 (19.2, 20.4) 9.2 (5.2, 14.7) 9.2 (5.2, 14.7) 4.6 (3.8, 5.6) 4.6 (3.8, 5.6) 15.2 (13.9, 16.6) 15.2 (13.9, 16.6) 8.7 (8.2, 9.2) 8.7 (8.2, 9.2) 3.0 (2.6, 3.4) 3.0 (2.6, 3.4) 11.9 (11.3, 12.5) 11.9 (11.3, 12.5) 62.1 (59.9, 64.2) 62.1 (59.9, 64.2) 10.9 (10.5, 11.2) 10.9 (10.5, 11.2) 16.6 (14.6, 18.7) 16.6 (14.6, 18.7) 23.9 (21.0, 26.9) 23.9 (21.0, 26.9) 4.6 (1.9, 9.2) 4.6 (1.9, 9.2) 20.0 (18.6, 21.5) 20.0 (18.6, 21.5) 20.2 (12.8, 29.5) 20.2 (12.8, 29.5) 8.2 (7.1, 9.5) 8.2 (7.1, 9.5) 5.4 (4.4, 6.7) 5.4 (4.4, 6.7) 11.2 (10.6, 11.9) 11.2 (10.6, 11.9) 8.5 (8.2, 8.8) 8.5 (8.2, 8.8) 20.5 (20.1, 20.9) 20.5 (20.1, 20.9) 14.6 (13.3, 15.9) 14.6 (13.3, 15.9) 16.9 (15.7, 18.2) 16.9 (15.7, 18.2) 4.4 (1.8, 8.8) 4.4 (1.8, 8.8) 43.0 (39.1, 47.0) 43.0 (39.1, 47.0) 12.0 (10.2, 14.0) 12.0 (10.2, 14.0) 36.1 (33.6, 38.7) 36.1 (33.6, 38.7) 51.1 (49.6, 52.6) 51.1 (49.6, 52.6) 16.1 (12.6, 20.0) 16.1 (12.6, 20.0)
80 Greece Fotiou Greece 2014 15 1320 219 16.6 (14.6, 18.7)
Iceland Kristjansson Iceland 2015 15-16 3477 587 16.9 (15.7, 18.2) 60
Ireland Babineau Ireland 2014 16-17 821 196 23.9 (21.0, 26.9)
Italy
40 Gallus Italy 2013 16-19 163 15 9.2 (5.2, 14.7) Gallus Italy 2014 16-19 153 7 4.6 (1.9, 9.2) Gallus Italy 2015 16-19 160 7 4.4 (1.8, 8.8)
30 Subtotal (I^2 = 45.9%, p = 0.2) 5.9 (3.3, 9.2)
Korea 2008 13-19 4341 22 0.5 (0.3, 0.8) 20 Cho Korea Lee Korea 2011 13-18 75643 7110 9.4 (9.2, 9.6) Subtotal (I^2 = 72.9%, p = 0.1) 8.6 (8.5, 8.8)
10 New Zealand White New Zealand 2012 14-15 3127 219 7.0 (6.1, 8.0) White New Zealand 2014 14-15 2919 584 20.0 (18.6, 21.5)
0 Li New Zealand 2014 15-17 99 20 20.2 (12.8, 29.5) Subtotal (I^2 = 99.2%, p = 0.0) 14.9 (5.5, 27.7)
Poland Goniewicz Poland 2010-2011 15-24 13787 2881 20.9 (20.2, 21.6) Goniewicz Poland 2013-2014 15-19 1970 1223 62.1 (59.9, 64.2)
Number of participants 16586 163 2177 2769 12615 8111 10190 1970 32051 1320 821 153 2919 99 2068 1601 9055 36979 32921 2892 3477 160 621 1205 1418 4486 Subtotal (I^2 = 99.6%, p = 0.0) 25.5 (24.8, 26.1)
UK SALSUS UK (Scotland) 2013-2014 13-15 32051 3487 10.9 (10.5, 11.2) Moore UK (Wales) 2014 11-16 9055 1018 11.2 (10.6, 11.9) Moore UK (Wales) 2014 10-11 1601 87 5.4 (4.4, 6.7) Subtotal (I^2 = 96.9%, p = 0.0) 9.2 (7.2, 11.3) Outcome (n) 3284 15 100 421 1098 243 1213 1223 3487 219 196 7 584 20 170 87 1018 3143 6749 422 587 7 267 145 512 2292 US Porter US (Florida) 2011 11-14 6045 181 3.0 (2.6, 3.5) Corey US NYTS 2011 11-14 8880 124 1.4 (1.2, 1.7) Pepper US National 2011 12-18 228 2 0.9 (0.1, 3.1)
Age range 15-19 16-19 11-18 15-18 11-18 11-14 15-18 15-19 13-15 15 16-17 16-19 14-15 15-17 11-18 10-11 11-16 11-14 15-18 14-18 15-16 16-19 16 11-16 14-18 14-18 Porter US (Florida) 2011 15-18 6163 370 6.0 (5.4, 6.6) Corey US NYTS 2011 15-18 9720 457 4.7 (4.3, 5.1) Porter US (Florida) 2012 11-14 36989 1443 3.9 (3.7, 4.1) Corey US NYTS 2012 11-14 11667 315 2.7 (2.4, 3.0) Porter US (Florida) 2012 15-18 36439 3061 8.4 (8.1, 8.7) Corey US NYTS 2012 15-18 12899 1290 10.0 (9.5, 10.5) Arrazola US NYTS 2013 11-14 8111 243 3.0 (2.6, 3.4) Barnett US (Florida) 2013 11-18 12615 1098 8.7 (8.2, 9.2) Anand US (California) 2013 15-18 2769 421 15.2 (13.9, 16.6) Arrazola US NYTS 2013 15-18 10190 1213 11.9 (11.3, 12.5) Porter US (Florida) 2014 11-14 36979 3143 8.5 (8.2, 8.8) Porter US (Florida) 2014 15-18 32921 6749 20.5 (20.1, 20.9) Alaska US (Alaska) 2015 14-18 1418 512 36.1 (33.6, 38.7) Montana US (Montana) 2015 14-18 4486 2292 51.1 (49.6, 52.6) Subtotal (I^2 = 99.9%, p = 0.0) 9.3 (6.1, 13.2)
Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.8%, p = 0.0); 11.4 (9.0, 14.0)
0 10 20 30 40 60 80 Source Reid [Canada, 2013] Gallus [Italy, 2013] Eastwood [UK (England), 2013] Anand [US (California), 2013] Barnett [US (Florida), 2013] Arrazola [US NYTS, 2013] Arrazola [US NYTS, 2013] Goniewicz [Poland, 2013-2014] SALSUS [UK (Scotland), 2013-2014] Fotiou [Greece, 2014] Babineau [Ireland, 2014] Gallus [Italy, 2014] White [New Zealand, 2014] Li [New Zealand, 2014] Eastwood [UK (England), 2014] Moore [UK (Wales), 2014] Moore [UK (Wales), 2014] Porter [US (Florida), 2014] Porter [US (Florida), 2014] Hamilton [Canada (Ontario), 2015] Kristjansson [Iceland, 2015] Gallus [Italy, 2015] Suris [Switzerland, 2015] Ford [UK (England), 2015] Alaska [US (Alaska), 2015] Montana [US (Montana), 2015] Overall (I^2 = 99.8%, p 0.0) Figure 6: Sensitivity analysis of ever e-cigarette use among youth from 2013-2015 from youth among use e-cigarette ever of analysis Sensitivity 6: Figure This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 7: Pooled analysis of ever e-cigarette use among youth by country (2008-2015)
Data Age Outcome Author Country collection range N (n) ES (95% CI)
Canada Reid Canada 2013 15-19 16586 3284 19.8 (19.2, 20.4)
Canada (Ontario) Hamilton Canada (Ontario) 2015 14-18 2892 422 14.6 (13.3, 15.9)
France Dautzenberg France (Paris) 2012 12-19 3409 277 8.1 (7.2, 9.1)
Greece Fotiou Greece 2014 15 1320 219 16.6 (14.6, 18.7)
Iceland Kristjansson Iceland 2015 15-16 3477 587 16.9 (15.7, 18.2)
Ireland Babineau Ireland 2014 16-17 821 196 23.9 (21.0, 26.9)
Italy Gallus Italy 2013 16-19 163 15 9.2 (5.2, 14.7) Gallus Italy 2014 16-19 153 7 4.6 (1.9, 9.2) Gallus Italy 2015 16-19 160 7 4.4 (1.8, 8.8) Subtotal (I^2 = 45.9%, p = 0.2) 5.9 (3.3, 9.2)
Korea Cho Korea 2008 13-19 4341 22 0.5 (0.3, 0.8) Lee Korea 2011 13-18 75643 7110 9.4 (9.2, 9.6) Subtotal (I^2 = 72.9%, p = 0.1) 8.6 (8.5, 8.8)
New Zealand White New Zealand 2012 14-15 3127 219 7.0 (6.1, 8.0) White New Zealand 2014 14-15 2919 584 20.0 (18.6, 21.5) Li New Zealand 2014 15-17 99 20 20.2 (12.8, 29.5) Subtotal (I^2 = 99.2%, p = 0.0) 14.9 (5.5, 27.7)
Poland Goniewicz Poland 2010-2011 15-24 13787 2881 20.9 (20.2, 21.6) Goniewicz Poland 2013-2014 15-19 1970 1223 62.1 (59.9, 64.2) Subtotal (I^2 = 99.6%, p = 0.0) 25.5 (24.8, 26.1)
UK SALSUS UK (Scotland) 2013-2014 13-15 32051 3487 10.9 (10.5, 11.2) Moore UK (Wales) 2014 11-16 9055 1018 11.2 (10.6, 11.9) Moore UK (Wales) 2014 10-11 1601 87 5.4 (4.4, 6.7) Subtotal (I^2 = 96.9%, p = 0.0) 9.2 (7.2, 11.3)
US Porter US (Florida) 2011 11-14 6045 181 3.0 (2.6, 3.5) Corey US NYTS 2011 11-14 8880 124 1.4 (1.2, 1.7) Pepper US National 2011 12-18 228 2 0.9 (0.1, 3.1) Porter US (Florida) 2011 15-18 6163 370 6.0 (5.4, 6.6) Corey US NYTS 2011 15-18 9720 457 4.7 (4.3, 5.1) Porter US (Florida) 2012 11-14 36989 1443 3.9 (3.7, 4.1) Corey US NYTS 2012 11-14 11667 315 2.7 (2.4, 3.0) Porter US (Florida) 2012 15-18 36439 3061 8.4 (8.1, 8.7) Corey US NYTS 2012 15-18 12899 1290 10.0 (9.5, 10.5) Arrazola US NYTS 2013 11-14 8111 243 3.0 (2.6, 3.4) Barnett US (Florida) 2013 11-18 12615 1098 8.7 (8.2, 9.2) Anand US (California) 2013 15-18 2769 421 15.2 (13.9, 16.6) Arrazola US NYTS 2013 15-18 10190 1213 11.9 (11.3, 12.5) Porter US (Florida) 2014 11-14 36979 3143 8.5 (8.2, 8.8) Porter US (Florida) 2014 15-18 32921 6749 20.5 (20.1, 20.9) Alaska US (Alaska) 2015 14-18 1418 512 36.1 (33.6, 38.7) Montana US (Montana) 2015 14-18 4486 2292 51.1 (49.6, 52.6) Subtotal (I^2 = 99.9%, p = 0.0) 9.3 (6.1, 13.2)
Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.8%, p = 0.0); 11.4 (9.0, 14.0)
0 10 20 30 40 60 80
69 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 2.6 (2.4, 2.9) 2.6 (2.4, 2.9) 9.0 (8.1, 9.9) 9.0 (8.1, 9.9) 1.8 (0.4, 5.3) 1.8 (0.4, 5.3) 7.4 (6.5, 8.4) 7.4 (6.5, 8.4) 3.9 (3.6, 4.3) 3.9 (3.6, 4.3) 1.1 (0.9, 1.3) 1.1 (0.9, 1.3) 4.5 (4.1, 4.9) 4.5 (4.1, 4.9) 29.9 (27.9, 32.0) 29.9 (27.9, 32.0) 0.9 (0.8, 1.0) 0.9 (0.8, 1.0) 0.5 (0.2, 1.1) 0.5 (0.2, 1.1) 3.2 (2.1, 4.6) 3.2 (2.1, 4.6) 0.7 (0.0, 3.6) 0.7 (0.0, 3.6) 0.0 (0.0, 3.7) 0.0 (0.0, 3.7) 1.4 (1.2, 1.6) 1.4 (1.2, 1.6) 13.9 (13.6, 14.2) 13.9 (13.6, 14.2) 4.0 (3.8, 4.2) 4.0 (3.8, 4.2) 10.8 (10.5, 11.1) 10.8 (10.5, 11.1) 3.9 (3.5, 4.3) 3.9 (3.5, 4.3) 13.4 (12.8, 14.0) 13.4 (12.8, 14.0) 1.3 (0.2, 4.4) 1.3 (0.2, 4.4) 17.7 (15.7, 19.8) 17.7 (15.7, 19.8) 29.5 (28.2, 30.9) 29.5 (28.2, 30.9) 5.6 (3.4, 8.3) 5.6 (3.4, 8.3) 40 30
20 10
0 Outcome (n) 431 362 3 205 492 89 459 589 276 7 26 1 0 125 5782 1479 3555 406 1536 2 251 1323 N 16586 4018 163 2769 12615 8111 10190 1970 32051 1320 821 153 99 9022 41600 36979 32921 10419 11459 160 1418 4486 Age range 15-19 13-15 16-19 15-18 11-18 11-14 15-18 15-19 13-15 15 16-17 16-19 15-17 11-16 13-18 11-14 15-18 11-14 15-18 16-19 14-18 14-18 Data collection 2013 2013 2013 2013 2013 2013 2013 2013-2014 2013-2014 2014 2014 2014 2014 2014 2014 2014 2014 2014 2014 2015 2015 2015 Country Canada Hungary Italy US (California) US (Florida) US NYTS US NYTS Poland UK (Scotland) Greece Ireland Italy New Zealand UK (Wales) US US (Florida) US (Florida) US NYTS US NYTS Italy US (Alaska) US (Montana) Figure 8: Pooled analysis of current e-cigarette use among youth from 2013-2015 from youth among use e-cigarette current of analysis Pooled 8: Figure 2013-2015 from youth among use e-cigarette current of analysis Sensitivity 9: Figure Author Reid Hungary Gallus Anand Barnett Arrazola Arrazola Goniewicz SALSUS Fotiou Babineau Gallus Li Moore Johnston Porter Porter Arrazola Arrazola Gallus Alaska Montana Overall (I^2 = 99.8%, p 0.0) This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 2.6 (2.4, 2.9) 2.6 (2.4, 2.9) 9.0 (8.1, 9.9) 9.0 (8.1, 9.9) 1.8 (0.4, 5.3) 1.8 (0.4, 5.3) 7.4 (6.5, 8.4) 7.4 (6.5, 8.4) 3.9 (3.6, 4.3) 3.9 (3.6, 4.3) 1.1 (0.9, 1.3) 1.1 (0.9, 1.3) 4.5 (4.1, 4.9) 4.5 (4.1, 4.9) 29.9 (27.9, 32.0) 29.9 (27.9, 32.0) 0.9 (0.8, 1.0) 0.9 (0.8, 1.0) 0.5 (0.2, 1.1) 0.5 (0.2, 1.1) 3.2 (2.1, 4.6) 3.2 (2.1, 4.6) 0.7 (0.0, 3.6) 0.7 (0.0, 3.6) 0.0 (0.0, 3.7) 0.0 (0.0, 3.7) 1.4 (1.2, 1.6) 1.4 (1.2, 1.6) 13.9 (13.6, 14.2) 13.9 (13.6, 14.2) 4.0 (3.8, 4.2) 4.0 (3.8, 4.2) 10.8 (10.5, 11.1) 10.8 (10.5, 11.1) 3.9 (3.5, 4.3) 3.9 (3.5, 4.3) 13.4 (12.8, 14.0) 13.4 (12.8, 14.0) 1.3 (0.2, 4.4) 1.3 (0.2, 4.4) 17.7 (15.7, 19.8) 17.7 (15.7, 19.8) 29.5 (28.2, 30.9) 29.5 (28.2, 30.9) 5.6 (3.4, 8.3) 5.6 (3.4, 8.3) 40 % % Weight Weight 3.78 3.78 3.77 3.77 3.44 3.44 3.75 3.75 3.76 3.76 3.78 3.78 3.77 3.77 3.77 3.77 3.75 3.75 3.78 3.78 3.74 3.74 3.71 3.71 3.42 3.42 3.26 3.26 3.75 3.75 3.74 3.74 3.77 3.77 3.78 3.78 3.78 3.78 3.78 3.78 3.77 3.77 3.78 3.78 3.44 3.44 3.69 3.69 3.74 3.74 3.74 3.74 3.77 3.77 100.00 100.00 ES (95% CI) ES (95% CI) 2.6 (2.4, 2.9) 2.6 (2.4, 2.9) 9.0 (8.1, 9.9) 9.0 (8.1, 9.9) 1.8 (0.4, 5.3) 1.8 (0.4, 5.3) 0.7 (0.4, 1.2) 0.7 (0.4, 1.2) 7.4 (6.5, 8.4) 7.4 (6.5, 8.4) 3.9 (3.6, 4.3) 3.9 (3.6, 4.3) 1.1 (0.9, 1.3) 1.1 (0.9, 1.3) 4.5 (4.1, 4.9) 4.5 (4.1, 4.9) 29.9 (27.9, 32.0) 29.9 (27.9, 32.0) 0.9 (0.8, 1.0) 0.9 (0.8, 1.0) 0.5 (0.2, 1.1) 0.5 (0.2, 1.1) 3.2 (2.1, 4.6) 3.2 (2.1, 4.6) 0.7 (0.0, 3.6) 0.7 (0.0, 3.6) 0.0 (0.0, 3.7) 0.0 (0.0, 3.7) 1.7 (1.2, 2.3) 1.7 (1.2, 2.3) 3.5 (2.6, 4.6) 3.5 (2.6, 4.6) 1.4 (1.2, 1.6) 1.4 (1.2, 1.6) 13.9 (13.6, 14.2) 13.9 (13.6, 14.2) 4.0 (3.8, 4.2) 4.0 (3.8, 4.2) 10.8 (10.5, 11.1) 10.8 (10.5, 11.1) 3.9 (3.5, 4.3) 3.9 (3.5, 4.3) 13.4 (12.8, 14.0) 13.4 (12.8, 14.0) 1.3 (0.2, 4.4) 1.3 (0.2, 4.4) 24.0 (20.7, 27.6) 24.0 (20.7, 27.6) 5.2 (4.1, 6.5) 5.2 (4.1, 6.5) 17.7 (15.7, 19.8) 17.7 (15.7, 19.8) 29.5 (28.2, 30.9) 29.5 (28.2, 30.9) 5.5 (3.5, 7.9) 5.5 (3.5, 7.9) 30 80 60
20
40 30 20 10 10
0 Number of participants 16586 4018 163 2177 2769 12615 8111 10190 1970 32051 1320 821 153 99 2068 1405 9022 41600 36979 32921 10419 11459 160 621 1332 1418 4486
0 Outcome (n) 431 362 3 16 205 492 89 459 589 276 7 26 1 0 35 49 125 5782 1479 3555 406 1536 2 149 69 251 1323 Outcome (n) 431 362 3 205 492 89 459 589 276 7 26 1 0 125 5782 1479 3555 406 1536 2 251 1323 Age range 15-19 13-15 16-19 15-18 11-18 11-14 15-18 15-19 13-15 15 16-17 16-19 15-17 11-18 16-20 11-16 13-18 11-14 15-18 11-14 15-18 16-19 16 16-20 14-18 14-18 N 16586 4018 163 2769 12615 8111 10190 1970 32051 1320 821 153 99 9022 41600 36979 32921 10419 11459 160 1418 4486 Age range 15-19 13-15 16-19 15-18 11-18 11-14 15-18 15-19 13-15 15 16-17 16-19 15-17 11-16 13-18 11-14 15-18 11-14 15-18 16-19 14-18 14-18 Data collection 2013 2013 2013 2013 2013 2013 2013 2013-2014 2013-2014 2014 2014 2014 2014 2014 2014 2014 2014 2014 2014 2015 2015 2015 Country Canada Hungary Italy US (California) US (Florida) US NYTS US NYTS Poland UK (Scotland) Greece Ireland Italy New Zealand UK (Wales) US US (Florida) US (Florida) US NYTS US NYTS Italy US (Alaska) US (Montana) Source Reid [Canada, 2013] Hungary [Hungary, 2013] Gallus [Italy, 2013] Eastwood [UK (England), 2013] Anand [US (California), 2013] Barnett [US (Florida), 2013] Arrazola [US NYTS, 2013] Arrazola [US NYTS, 2013] Goniewicz [Poland, 2013-2014] SALSUS [UK (Scotland), 2013-2014] Fotiou [Greece, 2014] Babineau [Ireland, 2014] Gallus [Italy, 2014] Li [New Zealand, 2014] Eastwood [UK (England), 2014] Smoking [UK (England), 2014] Moore [UK (Wales), 2014] Johnston [US, 2014] Porter [US (Florida), 2014] Porter [US (Florida), 2014] Arrazola [US NYTS, 2014] Arrazola [US NYTS, 2014] Gallus [Italy, 2015] Suris [Switzerland, 2015] Smoking [UK (England), 2015] Alaska [US (Alaska), 2015] Montana [US (Montana), 2015] Overall (I^2 = 99.8%, p 0.0) Figure 9: Sensitivity analysis of current e-cigarette use among youth from 2013-2015 from youth among use e-cigarette current of analysis Sensitivity 9: Figure
Author Reid Hungary Gallus Anand Barnett Arrazola Arrazola Goniewicz SALSUS Fotiou Babineau Gallus Li Moore Johnston Porter Porter Arrazola Arrazola Gallus Alaska Montana Overall (I^2 = 99.8%, p 0.0) 71 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 10: Pooled analysis of current e-cigarette use among youth by country (2008-2015)
Data Age Outcome Author Country collection range N (n) ES (95% CI)
Poland Goniewicz Poland 2010-2011 15-24 13787 1131 8.2 (7.8, 8.7) Goniewicz Poland 2013-2014 15-19 1970 589 29.9 (27.9, 32.0) Subtotal (I^2 = 100.0%, p = 0.0) 10.3 (9.8, 10.8)
Korea Lee Korea 2011 13-18 75643 3555 4.7 (4.5, 4.9)
US Porter US (Florida) 2011 11-14 6045 91 1.5 (1.2, 1.8) Corey US NYTS 2011 11-14 8880 53 0.6 (0.4, 0.8) Porter US (Florida) 2011 15-18 6163 191 3.1 (2.7, 3.6) Corey US NYTS 2011 15-18 9720 146 1.5 (1.3, 1.8) Porter US (Florida) 2012 11-14 36989 666 1.8 (1.7, 1.9) Corey US NYTS 2012 11-14 11667 128 1.1 (0.9, 1.3) Porter US (Florida) 2012 15-18 36439 1275 3.5 (3.3, 3.7) Corey US NYTS 2012 15-18 12899 361 2.8 (2.5, 3.1) Arrazola US NYTS 2013 11-14 8111 89 1.1 (0.9, 1.3) Barnett US (Florida) 2013 11-18 12615 492 3.9 (3.6, 4.3) Anand US (California) 2013 15-18 2769 205 7.4 (6.5, 8.4) Arrazola US NYTS 2013 15-18 10190 459 4.5 (4.1, 4.9) Porter US (Florida) 2014 11-14 36979 1479 4.0 (3.8, 4.2) Arrazola US NYTS 2014 11-14 10419 406 3.9 (3.5, 4.3) Johnston US 2014 13-18 41600 5782 13.9 (13.6, 14.2) Porter US (Florida) 2014 15-18 32921 3555 10.8 (10.5, 11.1) Arrazola US NYTS 2014 15-18 11459 1536 13.4 (12.8, 14.0) Alaska US (Alaska) 2015 14-18 1418 251 17.7 (15.7, 19.8) Montana US (Montana) 2015 14-18 4486 1323 29.5 (28.2, 30.9) Subtotal (I^2 = 99.9%, p = 0.0) 5.2 (3.2, 7.7)
Hungary Hungary Hungary 2012 13-15 2325 302 13.0 (11.6, 14.4) Hungary Hungary 2013 13-15 4018 362 9.0 (8.1, 9.9) Subtotal (I^2 = 100.0%, p = 0.0) 10.4 (9.7, 11.2)
China (Hong Kong) Wang China (Hong Kong) 2012-2013 12-18 45128 496 1.1 (1.0, 1.2)
Canada Reid Canada 2013 15-19 16586 431 2.6 (2.4, 2.9)
Italy Gallus Italy 2013 16-19 163 3 1.8 (0.4, 5.3) Gallus Italy 2014 16-19 153 1 0.7 (0.0, 3.6) Gallus Italy 2015 16-19 160 2 1.3 (0.2, 4.4) Subtotal (I^2 = 0.0%, p = 0.7) 1.2 (0.3, 2.5)
UK SALSUS UK (Scotland) 2013-2014 13-15 32051 276 0.9 (0.8, 1.0) Moore UK (Wales) 2014 11-16 9022 125 1.4 (1.2, 1.6) Subtotal (I^2 = 0.0%, p = 0.4) 1.0 (0.9, 1.1)
Greece Fotiou Greece 2014 15 1320 7 0.5 (0.2, 1.1)
Ireland Babineau Ireland 2014 16-17 821 26 3.2 (2.1, 4.6)
New Zealand Li New Zealand 2014 15-17 99 0 0.0 (0.0, 3.7)
Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.8%, p = 0.0); 4.6 (3.2, 6.2)
0 10 20 30 40 Figure 11: Pooled analysis of ever e-cigarette use among non-smoking youth from 2013-2015 from youth non-smoking among use e-cigarette ever of analysis Pooled 11: Figure This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 13.6 (13.3, 13.9) 13.6 (13.3, 13.9) 5.1 (2.1, 10.3) 5.1 (2.1, 10.3) 4.2 (3.8, 4.6) 4.2 (3.8, 4.6) 7.5 (7.2, 7.8) 7.5 (7.2, 7.8) 8.5 (6.9, 10.3) 8.5 (6.9, 10.3) 12.1 (9.7, 14.8) 12.1 (9.7, 14.8) 0.7 (0.0, 3.9) 0.7 (0.0, 3.9) 14.0 (12.7, 15.4) 14.0 (12.7, 15.4) 5.1 (4.1, 6.3) 5.1 (4.1, 6.3) 7.4 (6.9, 8.0) 7.4 (6.9, 8.0) 6.3 (5.3, 7.3) 6.3 (5.3, 7.3) 9.1 (8.1, 10.2) 9.1 (8.1, 10.2) 1.4 (0.2, 5.0) 1.4 (0.2, 5.0) 7.0 (5.1, 9.3) 7.0 (5.1, 9.3) 20 15
10 5
0 Outcome (n) 5187 7 492 2222 91 81 1 356 81 637 153 270 2 N 38140 136 11719 29508 1076 670 139 2544 1581 8564 2448 2963 141 Age range 15-19 16-19 11-18 13-15 16-17 16-19 14-15 10-11 11-16 14-18 16-19 Data collection 2013 2013 2013 2013-2014 2014 2014 2014 2014 2014 2014 2015 2015 2015 Country Canada Italy US (Florida) UK (Scotland) Greece Ireland Italy New Zealand UK (Wales) UK (Wales) Canada (Ontario) Iceland Italy Figure 11: Pooled analysis of ever e-cigarette use among non-smoking youth from 2013-2015 from youth non-smoking among use e-cigarette ever of analysis Pooled 11: Figure
73 PrevalenceAuthor of smoking-proxyReid Gallus electronicBarnett SALSUS inhalingFotiou systemBabineau (SEIS)Gallus useWhite and itsMoore associationMoore Hamilton with tobaccoKristjansson initiationGallus Overall (I^2 = 99.2%, p 0.0) in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. % % Weight Weight 7.11 7.11 5.40 5.40 6.96 6.96 7.09 7.09 7.10 7.10 6.84 6.84 6.68 6.68 5.43 5.43 7.00 7.00 6.95 6.95 7.08 7.08 6.93 6.93 6.99 6.99 7.01 7.01 5.45 5.45 100.00 100.00 ES (95% CI) ES (95% CI) 13.6 (13.3, 13.9) 13.6 (13.3, 13.9) 5.1 (2.1, 10.3) 5.1 (2.1, 10.3) 1.8 (1.3, 2.5) 1.8 (1.3, 2.5) 4.2 (3.8, 4.6) 4.2 (3.8, 4.6) 7.5 (7.2, 7.8) 7.5 (7.2, 7.8) 8.5 (6.9, 10.3) 8.5 (6.9, 10.3) 12.1 (9.7, 14.8) 12.1 (9.7, 14.8) 0.7 (0.0, 3.9) 0.7 (0.0, 3.9) 14.0 (12.7, 15.4) 14.0 (12.7, 15.4) 4.6 (3.7, 5.7) 4.6 (3.7, 5.7) 7.4 (6.9, 8.0) 7.4 (6.9, 8.0) 5.1 (4.1, 6.3) 5.1 (4.1, 6.3) 6.3 (5.3, 7.3) 6.3 (5.3, 7.3) 9.1 (8.1, 10.2) 9.1 (8.1, 10.2) 1.4 (0.2, 5.0) 1.4 (0.2, 5.0) 6.4 (4.6, 8.5) 6.4 (4.6, 8.5) 80 60
40 30 20 10
0 Number of participants 38140 136 1888 11719 29508 1076 670 139 2544 1790 8564 1581 2448 2963 141 Outcome (n) 5187 7 34 492 2222 91 81 1 356 83 637 81 153 270 2 Age range 15-19 16-19 11-18 13-15 16-17 16-19 14-15 11-16 10-11 14-18 16-19 Figure 12: Sensitivity analysis of ever e-cigarette use among non-smoking youth from 2013-2015 from youth non-smoking among use e-cigarette ever of analysis Sensitivity 12: Figure (2008-2015) country by youth non-smoking among use e-cigarette ever of analysis Pooled 13: Figure Source Reid [Canada, 2013] Gallus [Italy, 2013] Eastwood [UK (England), 2013] Barnett [US (Florida), 2013] SALSUS [UK (Scotland), 2013-2014] Fotiou [Greece, 2014] Babineau [Ireland, 2014] Gallus [Italy, 2014] White [New Zealand, 2014] Eastwood [UK (England), 2014] Moore [UK (Wales), 2014] Moore [UK (Wales), 2014] Hamilton [Canada (Ontario), 2015] Kristjansson [Iceland, 2015] Gallus [Italy, 2015] Overall (I^2 = 99.2%, p 0.0) This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 0.1 (0.0, 0.3) 0.1 (0.0, 0.3) 8.7 (8.1, 9.3) 8.7 (8.1, 9.3) 1.8 (1.6, 2.0) 1.8 (1.6, 2.0) 4.4 (4.1, 4.6) 4.4 (4.1, 4.6) 4.2 (3.8, 4.6) 4.2 (3.8, 4.6) 3.3 (1.8, 5.4) 3.3 (1.8, 5.4) 13.6 (13.3, 13.9) 13.6 (13.3, 13.9) 5.1 (2.1, 10.3) 5.1 (2.1, 10.3) 0.7 (0.0, 3.9) 0.7 (0.0, 3.9) 1.4 (0.2, 5.0) 1.4 (0.2, 5.0) 2.1 (0.3, 5.1) 2.1 (0.3, 5.1) 7.5 (7.2, 7.8) 7.5 (7.2, 7.8) 5.1 (4.1, 6.3) 5.1 (4.1, 6.3) 7.4 (6.9, 8.0) 7.4 (6.9, 8.0) 6.9 (6.0, 7.8) 6.9 (6.0, 7.8) 8.5 (6.9, 10.3) 8.5 (6.9, 10.3) 12.1 (9.7, 14.8) 12.1 (9.7, 14.8) 14.0 (12.7, 15.4) 14.0 (12.7, 15.4) 6.3 (5.3, 7.3) 6.3 (5.3, 7.3) 9.1 (8.1, 10.2) 9.1 (8.1, 10.2) 5.8 (3.8, 8.1) 5.8 (3.8, 8.1) 20 15
10 5
0 Outcome (n) 5 785 292 945 492 5187 7 1 2 2222 81 637 91 81 356 153 270 N 3402 9022 16575 21660 11719 38140 136 139 141 29508 1581 8564 1076 670 2544 2448 2963 Age range 13-19 15-24 11-18 11-18 11-18 15-19 16-19 16-19 16-19 13-15 10-11 11-16 16-17 14-15 14-18 Data collection 2008 2010-2011 2011 2012 2013 2013 2013 2014 2015 2013-2014 2014 2014 2014 2014 2014 2015 2015 Country Korea Poland US NYTS US NYTS US (Florida) Canada Italy Italy Italy UK (Scotland) UK (Wales) UK (Wales) Greece Ireland New Zealand Canada (Ontario) Iceland Author Korea Cho Poland Goniewicz US Dutra Dutra Barnett Subtotal (I^2 = 99.2%, p 0.0) Canada Reid Italy Gallus Gallus Gallus Subtotal (I^2 = 63.1%, p 0.1) UK SALSUS Moore Moore Subtotal (I^2 = 86.2%, p 0.0) Greece Fotiou Ireland Babineau New Zealand White Canada (Ontario) Hamilton Iceland Kristjansson Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.6%, p 0.0); Figure 13: Pooled analysis of ever e-cigarette use among non-smoking youth by country (2008-2015) country by youth non-smoking among use e-cigarette ever of analysis Pooled 13: Figure
75 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 0.0 (0.0, 2.7) 0.0 (0.0, 2.7) 19.0 (18.3, 19.7) 19.0 (18.3, 19.7) 13.0 (11.2, 15.0) 13.0 (11.2, 15.0) 0.1 (0.1, 0.1) 0.1 (0.1, 0.1) 0.2 (0.0, 0.7) 0.2 (0.0, 0.7) 1.5 (0.7, 2.7) 1.5 (0.7, 2.7) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 0.6 (0.5, 0.8) 0.6 (0.5, 0.8) 2.8 (2.6, 3.0) 2.8 (2.6, 3.0) 6.9 (6.6, 7.2) 6.9 (6.6, 7.2) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 2.2 (0.3, 5.6) 2.2 (0.3, 5.6) 20
10
0 Outcome (n) 0 2227 159 24 2 10 0 54 1006 2074 0 N 136 11719 1221 29508 1076 670 139 8564 35920 30065 141 Age range 16-19 11-18 15-19 13-15 16-17 16-19 11-16 11-14 15-18 16-19 Data collection 2013 2013 2013-2014 2013-2014 2014 2014 2014 2014 2014 2014 2015 Country Italy US (Florida) Poland UK (Scotland) Greece Ireland Italy UK (Wales) US (Florida) US (Florida) Italy Figure 14: Pooled analysis of current e-cigarette use among non-smoking youth from 2013-2015 from youth non-smoking among use e-cigarette current of analysis Pooled 14: Figure 2013-2015 from youth non-smoking among use e-cigarette current of analysis Sensitivity 15: Figure Author Gallus Barnett Goniewicz SALSUS Fotiou Babineau Gallus Moore Porter Porter Gallus Overall (I^2 = 99.9%, p 0.0) This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. % % Weight Weight 5.88 5.88 6.86 6.86 6.94 6.94 6.81 6.81 6.94 6.94 6.79 6.79 6.70 6.70 5.90 5.90 6.86 6.86 6.80 6.80 6.93 6.93 6.95 6.95 6.94 6.94 5.91 5.91 6.79 6.79 100.00 100.00 ES (95% CI) ES (95% CI) 0.0 (0.0, 2.7) 0.0 (0.0, 2.7) 0.3 (0.1, 0.6) 0.3 (0.1, 0.6) 2.7 (2.4, 3.0) 2.7 (2.4, 3.0) 13.0 (11.2, 15.0) 13.0 (11.2, 15.0) 0.1 (0.1, 0.1) 0.1 (0.1, 0.1) 0.2 (0.0, 0.7) 0.2 (0.0, 0.7) 1.5 (0.7, 2.7) 1.5 (0.7, 2.7) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 1.5 (1.0, 2.1) 1.5 (1.0, 2.1) 0.5 (0.2, 1.2) 0.5 (0.2, 1.2) 0.6 (0.5, 0.8) 0.6 (0.5, 0.8) 2.8 (2.6, 3.0) 2.8 (2.6, 3.0) 6.9 (6.6, 7.2) 6.9 (6.6, 7.2) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 1.3 (0.7, 2.1) 1.3 (0.7, 2.1) 1.3 (0.4, 2.8) 1.3 (0.4, 2.8) 80 60
40 30 20 10
0 Number of participants 136 1888 11719 1221 29508 1076 670 139 1790 1128 8564 35920 30065 141 1040 Outcome (n) 0 5 316 159 24 2 10 0 26 6 54 1006 2074 0 13 Age range 16-19 11-18 15-19 13-15 16-17 16-19 16-20 11-16 11-14 15-18 16-19 16-20 Figure 15: Sensitivity analysis of current e-cigarette use among non-smoking youth from 2013-2015 from youth non-smoking among use e-cigarette current of analysis Sensitivity 15: Figure
77Source PrevalenceGallus [Italy, 2013] of smoking-proxyEastwood [UK (England), 2013] Barnett [US (Florida), 2013] electronicGoniewicz [Poland, 2013-2014] SALSUS [UK (Scotland), 2013-2014] inhalingFotiou [Greece, 2014] systemBabineau [Ireland, 2014] (SEIS)Gallus [Italy, 2014] useEastwood [UK (England), 2014] and itsSmoking [UK (England), 2014] associationMoore [UK (Wales), 2014] withPorter [US (Florida), 2014] tobaccoPorter [US (Florida), 2014] initiationGallus [Italy, 2015] Smoking [UK (England), 2015] in youths:Overall (I^2 = 99.6%, p 0.0) a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 2.4 (2.1, 2.7) 2.4 (2.1, 2.7) 13.0 (11.2, 15.0) 13.0 (11.2, 15.0) 3.2 (2.9, 3.6) 3.2 (2.9, 3.6) 5.7 (5.5, 5.9) 5.7 (5.5, 5.9) 0.7 (0.5, 1.0) 0.7 (0.5, 1.0) 0.8 (0.6, 1.1) 0.8 (0.6, 1.1) 0.6 (0.5, 0.7) 0.6 (0.5, 0.7) 1.1 (0.9, 1.2) 1.1 (0.9, 1.2) 19.0 (18.3, 19.7) 19.0 (18.3, 19.7) 2.8 (2.6, 3.0) 2.8 (2.6, 3.0) 6.9 (6.6, 7.2) 6.9 (6.6, 7.2) 3.1 (0.8, 6.9) 3.1 (0.8, 6.9) 4.7 (3.8, 5.8) 4.7 (3.8, 5.8) 0.6 (0.5, 0.6) 0.6 (0.5, 0.6) 0.0 (0.0, 2.7) 0.0 (0.0, 2.7) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 0.0 (0.0, 0.5) 0.0 (0.0, 0.5) 0.1 (0.1, 0.1) 0.1 (0.1, 0.1) 0.6 (0.5, 0.8) 0.6 (0.5, 0.8) 0.2 (0.1, 0.2) 0.2 (0.1, 0.2) 0.2 (0.0, 0.7) 0.2 (0.0, 0.7) 1.5 (0.7, 2.7) 1.5 (0.7, 2.7) 2.0 (0.8, 3.7) 2.0 (0.8, 3.7) 20
10
0 Outcome (n) 217 159 3698 41 43 98 232 2227 1006 2074 80 221 0 0 0 24 54 2 10 N 9022 1221 64983 5791 5362 16575 21660 11719 35920 30065 1697 40179 136 139 141 29508 8564 1076 670 Age range 15-24 15-19 13-18 11-14 15-18 11-18 11-18 11-18 11-14 15-18 13-15 12-18 16-19 16-19 16-19 13-15 11-16 16-17 Data collection 2010-2011 2013-2014 2011 2011 2011 2011 2012 2013 2014 2014 2012 2012-2013 2013 2014 2015 2013-2014 2014 2014 2014 Country Poland Poland Korea US (Florida) US (Florida) US NYTS US NYTS US (Florida) US (Florida) US (Florida) Hungary China (Hong Kong) Italy Italy Italy UK (Scotland) UK (Wales) Greece Ireland Author Poland Goniewicz Goniewicz Subtotal (I^2 = 100.0%, p 0.0) Korea Lee US Porter Porter Dutra Dutra Barnett Porter Porter Subtotal (I^2 = 99.9%, p 0.0) Hungary Hungary China (Hong Kong) Wang Italy Gallus Gallus Gallus Subtotal (I^2 = 0.0%, p 1.0) UK SALSUS Moore Subtotal (I^2 = 0.0%, p 1.0) Greece Fotiou Ireland Babineau Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.8%, p 0.0); Figure 16: Pooled analysis of current e-cigarette use among non-smoking youth by country (2010-2015) country by youth non-smoking among use e-cigarette current of analysis Pooled 16: Figure 2013-2015 from youth smoking among use e-cigarette ever of analysis Pooled 17: Figure This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 72.5 (71.6, 73.4) 72.5 (71.6, 73.4) 29.6 (13.8, 50.2) 29.6 (13.8, 50.2) 67.3 (64.1, 70.4) 67.3 (64.1, 70.4) 49.7 (47.8, 51.7) 49.7 (47.8, 51.7) 52.5 (46.0, 58.9) 52.5 (46.0, 58.9) 58.9 (50.7, 66.9) 58.9 (50.7, 66.9) 35.7 (12.8, 64.9) 35.7 (12.8, 64.9) 60.8 (55.7, 65.8) 60.8 (55.7, 65.8) 50.0 (21.1, 78.9) 50.0 (21.1, 78.9) 52.9 (48.3, 57.5) 52.9 (48.3, 57.5) 57.2 (52.5, 61.9) 57.2 (52.5, 61.9) 61.7 (57.3, 65.9) 61.7 (57.3, 65.9) 26.3 (9.1, 51.2) 26.3 (9.1, 51.2) 54.7 (47.0, 62.3) 54.7 (47.0, 62.3) 80 ES (95% CI) ES (95% CI) 2.4 (2.1, 2.7) 2.4 (2.1, 2.7) 13.0 (11.2, 15.0) 13.0 (11.2, 15.0) 3.2 (2.9, 3.6) 3.2 (2.9, 3.6) 5.7 (5.5, 5.9) 5.7 (5.5, 5.9) 0.7 (0.5, 1.0) 0.7 (0.5, 1.0) 0.8 (0.6, 1.1) 0.8 (0.6, 1.1) 0.6 (0.5, 0.7) 0.6 (0.5, 0.7) 1.1 (0.9, 1.2) 1.1 (0.9, 1.2) 19.0 (18.3, 19.7) 19.0 (18.3, 19.7) 2.8 (2.6, 3.0) 2.8 (2.6, 3.0) 6.9 (6.6, 7.2) 6.9 (6.6, 7.2) 3.1 (0.8, 6.9) 3.1 (0.8, 6.9) 4.7 (3.8, 5.8) 4.7 (3.8, 5.8) 0.6 (0.5, 0.6) 0.6 (0.5, 0.6) 0.0 (0.0, 2.7) 0.0 (0.0, 2.7) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 0.0 (0.0, 2.6) 0.0 (0.0, 0.5) 0.0 (0.0, 0.5) 0.1 (0.1, 0.1) 0.1 (0.1, 0.1) 0.6 (0.5, 0.8) 0.6 (0.5, 0.8) 0.2 (0.1, 0.2) 0.2 (0.1, 0.2) 0.2 (0.0, 0.7) 0.2 (0.0, 0.7) 1.5 (0.7, 2.7) 1.5 (0.7, 2.7) 2.0 (0.8, 3.7) 2.0 (0.8, 3.7) 20 60
40
10 30 20 10
0
0 Outcome (n) 217 159 3698 41 43 98 232 2227 1006 2074 80 221 0 0 0 24 54 2 10 Outcome (n) 6571 8 603 1265 128 89 5 228 6 246 253 317 5 N 9022 1221 64983 5791 5362 16575 21660 11719 35920 30065 1697 40179 136 139 141 29508 8564 1076 670 Age range 15-24 15-19 13-18 11-14 15-18 11-18 11-18 11-18 11-14 15-18 13-15 12-18 16-19 16-19 16-19 13-15 11-16 16-17 N 9063 27 896 2543 244 151 14 375 12 465 442 514 19 Age range 15-19 16-19 11-18 13-15 16-17 16-19 14-15 10-11 11-16 14-18 16-19 Data collection 2010-2011 2013-2014 2011 2011 2011 2011 2012 2013 2014 2014 2012 2012-2013 2013 2014 2015 2013-2014 2014 2014 2014 Data collection 2013 2013 2013 2013-2014 2014 2014 2014 2014 2014 2014 2015 2015 2015 Country Poland Poland Korea US (Florida) US (Florida) US NYTS US NYTS US (Florida) US (Florida) US (Florida) Hungary China (Hong Kong) Italy Italy Italy UK (Scotland) UK (Wales) Greece Ireland Author Poland Goniewicz Goniewicz Subtotal (I^2 = 100.0%, p 0.0) Korea Lee US Porter Porter Dutra Dutra Barnett Porter Porter Subtotal (I^2 = 99.9%, p 0.0) Hungary Hungary China (Hong Kong) Wang Italy Gallus Gallus Gallus Subtotal (I^2 = 0.0%, p 1.0) UK SALSUS Moore Subtotal (I^2 = 0.0%, p 1.0) Greece Fotiou Ireland Babineau Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.8%, p 0.0); Country Canada Italy US (Florida) UK (Scotland) Greece Ireland Italy New Zealand UK (Wales) UK (Wales) Canada (Ontario) Iceland Italy Figure 17: Pooled analysis of ever e-cigarette use among smoking youth from 2013-2015 from youth smoking among use e-cigarette ever of analysis Pooled 17: Figure
79 PrevalenceAuthor of smoking-proxyReid Gallus Barnett electronicSALSUS inhalingFotiou systemBabineau (SEIS)Gallus useWhite and itsMoore associationMoore Hamilton with tobaccoKristjansson initiationGallus Overall (I^2 = 97.9%, p 0.0) in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. % % Weight Weight 7.86 7.86 5.14 5.14 7.20 7.20 7.74 7.74 7.82 7.82 7.43 7.43 7.18 7.18 3.92 3.92 7.57 7.57 7.11 7.11 7.63 7.63 3.63 3.63 7.62 7.62 7.65 7.65 4.50 4.50 100.00 100.00 ES (95% CI) ES (95% CI) 72.5 (71.6, 73.4) 72.5 (71.6, 73.4) 29.6 (13.8, 50.2) 29.6 (13.8, 50.2) 36.5 (29.0, 44.6) 36.5 (29.0, 44.6) 67.3 (64.1, 70.4) 67.3 (64.1, 70.4) 49.7 (47.8, 51.7) 49.7 (47.8, 51.7) 52.5 (46.0, 58.9) 52.5 (46.0, 58.9) 58.9 (50.7, 66.9) 58.9 (50.7, 66.9) 35.7 (12.8, 64.9) 35.7 (12.8, 64.9) 60.8 (55.7, 65.8) 60.8 (55.7, 65.8) 53.7 (44.9, 62.3) 53.7 (44.9, 62.3) 52.9 (48.3, 57.5) 52.9 (48.3, 57.5) 50.0 (21.1, 78.9) 50.0 (21.1, 78.9) 57.2 (52.5, 61.9) 57.2 (52.5, 61.9) 61.7 (57.3, 65.9) 61.7 (57.3, 65.9) 26.3 (9.1, 51.2) 26.3 (9.1, 51.2) 53.2 (45.9, 60.5) 53.2 (45.9, 60.5) 80 60
40 30 20 10
0 Number of participants 9063 27 156 896 2543 244 151 14 375 136 465 12 442 514 19 Outcome (n) 6571 8 57 603 1265 128 89 5 228 73 246 6 253 317 5 Age range 15-19 16-19 11-18 13-15 16-17 16-19 14-15 11-16 10-11 14-18 16-19 Figure 18: Sensitivity analysis of ever e-cigarette use among smoking youth from 2013-2015 from youth smoking among use e-cigarette ever of analysis Sensitivity 18: Figure (2008-2015) country by youth smoking among use e-cigarette ever of analysis Pooled 19: Figure Source Reid [Canada, 2013] Gallus [Italy, 2013] Eastwood [UK (England), 2013] Barnett [US (Florida), 2013] SALSUS [UK (Scotland), 2013-2014] Fotiou [Greece, 2014] Babineau [Ireland, 2014] Gallus [Italy, 2014] White [New Zealand, 2014] Eastwood [UK (England), 2014] Moore [UK (Wales), 2014] Moore [UK (Wales), 2014] Hamilton [Canada (Ontario), 2015] Kristjansson [Iceland, 2015] Gallus [Italy, 2015] Overall (I^2 = 97.8%, p 0.0) This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 2.0 (1.1, 3.2) 2.0 (1.1, 3.2) 43.1 (41.7, 44.5) 43.1 (41.7, 44.5) 28.1 (25.0, 31.5) 28.1 (25.0, 31.5) 58.1 (54.8, 61.4) 58.1 (54.8, 61.4) 67.3 (64.1, 70.4) 67.3 (64.1, 70.4) 51.1 (28.4, 73.5) 51.1 (28.4, 73.5) 72.5 (71.6, 73.4) 72.5 (71.6, 73.4) 29.6 (13.8, 50.2) 29.6 (13.8, 50.2) 35.7 (12.8, 64.9) 35.7 (12.8, 64.9) 26.3 (9.1, 51.2) 26.3 (9.1, 51.2) 29.9 (18.5, 42.5) 29.9 (18.5, 42.5) 49.7 (47.8, 51.7) 49.7 (47.8, 51.7) 50.0 (21.1, 78.9) 50.0 (21.1, 78.9) 52.9 (48.3, 57.5) 52.9 (48.3, 57.5) 50.2 (48.4, 52.1) 50.2 (48.4, 52.1) 52.5 (46.0, 58.9) 52.5 (46.0, 58.9) 58.9 (50.7, 66.9) 58.9 (50.7, 66.9) 60.8 (55.7, 65.8) 60.8 (55.7, 65.8) 57.2 (52.5, 61.9) 57.2 (52.5, 61.9) 61.7 (57.3, 65.9) 61.7 (57.3, 65.9) 47.0 (36.0, 58.1) 47.0 (36.0, 58.1) 80 60
40 30 20 10
0 Outcome (n) 16 2042 219 505 603 6571 8 5 5 1265 6 246 128 89 228 253 317 N 810 4738 778 869 896 9063 27 14 19 2543 12 465 244 151 375 442 514 Age range 13-19 15-24 11-18 11-18 11-18 15-19 16-19 16-19 16-19 13-15 10-11 11-16 16-17 14-15 14-18 Data collection 2008 2010-2011 2011 2012 2013 2013 2013 2014 2015 2013-2014 2014 2014 2014 2014 2014 2015 2015 Country Korea Poland US NYTS US NYTS US (Florida) Canada Italy Italy Italy UK (Scotland) UK (Wales) UK (Wales) Greece Ireland New Zealand Canada (Ontario) Iceland Author Korea Cho Poland Goniewicz US Dutra Dutra Barnett Subtotal (I^2 = 99.3%, p 0.0) Canada Reid Italy Gallus Gallus Gallus Subtotal (I^2 = 0.0%, p 0.8) UK SALSUS Moore Moore Subtotal (I^2 = 0.0%, p 0.5) Greece Fotiou Ireland Babineau New Zealand White Canada (Ontario) Hamilton Iceland Kristjansson Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.5%, p 0.0); Figure 19: Pooled analysis of ever e-cigarette use among smoking youth by country (2008-2015) country by youth smoking among use e-cigarette ever of analysis Pooled 19: Figure
81 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 11.1 (2.4, 29.2) 11.1 (2.4, 29.2) 2.7 (1.7, 4.0) 2.7 (1.7, 4.0) 57.4 (53.8, 61.0) 57.4 (53.8, 61.0) 9.9 (8.8, 11.1) 9.9 (8.8, 11.1) 2.0 (0.7, 4.7) 2.0 (0.7, 4.7) 10.6 (6.2, 16.6) 10.6 (6.2, 16.6) 7.1 (0.2, 33.9) 7.1 (0.2, 33.9) 15.3 (12.1, 18.9) 15.3 (12.1, 18.9) 44.8 (41.8, 47.9) 44.8 (41.8, 47.9) 51.7 (49.8, 53.5) 51.7 (49.8, 53.5) 5.3 (0.1, 26.0) 5.3 (0.1, 26.0) 17.2 (5.8, 32.6) 17.2 (5.8, 32.6) 80 60
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0 Outcome (n) 3 24 430 252 5 16 1 71 481 1481 1 N 27 896 749 2543 244 151 14 465 1073 2865 19 Age range 16-19 11-18 15-19 13-15 16-17 16-19 11-16 11-14 15-18 16-19 Data collection 2013 2013 2013-2014 2013-2014 2014 2014 2014 2014 2014 2014 2015 Country Italy US (Florida) Poland UK (Scotland) Greece Ireland Italy UK (Wales) US (Florida) US (Florida) Italy Figure 20: Pooled analysis of current e-cigarette use among smoking youth from 2013-2015 from youth smoking among use e-cigarette current of analysis Pooled 20: Figure 2013-2015 from youth smoking among use e-cigarette current of analysis Pooled 21: Figure Author Gallus Barnett Goniewicz SALSUS Fotiou Babineau Gallus Moore Porter Porter Gallus Overall (I^2 = 99.6%, p 0.0) This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. % % Weight Weight 6.09 6.09 6.80 6.80 6.94 6.94 6.94 6.94 6.96 6.96 6.86 6.86 6.79 6.79 5.47 5.47 6.78 6.78 6.87 6.87 6.91 6.91 6.95 6.95 6.96 6.96 5.79 5.79 6.88 6.88 100.00 100.00 ES (95% CI) ES (95% CI) 11.1 (2.4, 29.2) 11.1 (2.4, 29.2) 7.7 (4.0, 13.1) 7.7 (4.0, 13.1) 19.0 (16.5, 21.7) 19.0 (16.5, 21.7) 57.4 (53.8, 61.0) 57.4 (53.8, 61.0) 9.9 (8.8, 11.1) 9.9 (8.8, 11.1) 2.0 (0.7, 4.7) 2.0 (0.7, 4.7) 10.6 (6.2, 16.6) 10.6 (6.2, 16.6) 7.1 (0.2, 33.9) 7.1 (0.2, 33.9) 13.2 (8.0, 20.1) 13.2 (8.0, 20.1) 15.5 (11.5, 20.3) 15.5 (11.5, 20.3) 15.3 (12.1, 18.9) 15.3 (12.1, 18.9) 44.8 (41.8, 47.9) 44.8 (41.8, 47.9) 51.7 (49.8, 53.5) 51.7 (49.8, 53.5) 5.3 (0.1, 26.0) 5.3 (0.1, 26.0) 19.2 (14.8, 24.2) 19.2 (14.8, 24.2) 17.8 (8.8, 28.9) 17.8 (8.8, 28.9) 80 60
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0 Number of participants 27 156 896 749 2543 244 151 14 136 277 465 1073 2865 19 292 Outcome (n) 3 12 170 430 252 5 16 1 18 43 71 481 1481 1 56 Age range 16-19 11-18 15-19 13-15 16-17 16-19 16-20 11-16 11-14 15-18 16-19 16-20 Figure 21: Pooled analysis of current e-cigarette use among smoking youth from 2013-2015 from youth smoking among use e-cigarette current of analysis Pooled 21: Figure
Source 83 PrevalenceGallus [Italy, 2013] of smoking-proxyEastwood [UK (England), 2013] Barnett [US (Florida), 2013] electronicGoniewicz [Poland, 2013-2014] SALSUS [UK (Scotland), 2013-2014] inhalingFotiou [Greece, 2014] systemBabineau [Ireland, 2014] (SEIS)Gallus [Italy, 2014] useEastwood [UK (England), 2014] and itsSmoking [UK (England), 2014] associationMoore [UK (Wales), 2014] Porter [US (Florida), 2014] with tobaccoPorter [US (Florida), 2014] Gallus [Italy, 2015] initiationSmoking [UK (England), 2015] in youths:Overall (I^2 = 99.3%, p 0.0) a systematic review This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 15.3 (14.3, 16.4) 15.3 (14.3, 16.4) 57.4 (53.8, 61.0) 57.4 (53.8, 61.0) 20.0 (19.0, 21.1) 20.0 (19.0, 21.1) 36.6 (35.5, 37.7) 36.6 (35.5, 37.7) 18.9 (14.3, 24.3) 18.9 (14.3, 24.3) 18.4 (15.7, 21.2) 18.4 (15.7, 21.2) 9.8 (7.8, 12.1) 9.8 (7.8, 12.1) 26.5 (23.6, 29.5) 26.5 (23.6, 29.5) 2.7 (1.7, 4.0) 2.7 (1.7, 4.0) 44.8 (41.8, 47.9) 44.8 (41.8, 47.9) 51.7 (49.8, 53.5) 51.7 (49.8, 53.5) 22.4 (8.8, 40.0) 22.4 (8.8, 40.0) 4.4 (3.8, 5.0) 4.4 (3.8, 5.0) 11.1 (2.4, 29.2) 11.1 (2.4, 29.2) 7.1 (0.2, 33.9) 7.1 (0.2, 33.9) 5.3 (0.1, 26.0) 5.3 (0.1, 26.0) 8.1 (1.8, 17.1) 8.1 (1.8, 17.1) 9.9 (8.8, 11.1) 9.9 (8.8, 11.1) 15.3 (12.1, 18.9) 15.3 (12.1, 18.9) 10.6 (9.6, 11.8) 10.6 (9.6, 11.8) 2.0 (0.7, 4.7) 2.0 (0.7, 4.7) 10.6 (6.2, 16.6) 10.6 (6.2, 16.6) 17.4 (9.9, 26.4) 17.4 (9.9, 26.4) 80 60
40 30 20 10
0 Outcome (n) 725 430 2672 48 147 76 230 24 481 1481 218 3 1 1 252 71 5 16 N 4738 749 7302 254 801 778 869 896 1073 2865 4978 27 14 19 2543 465 244 151 Age range 15-24 15-19 13-18 11-14 15-18 11-18 11-18 11-18 11-14 15-18 12-18 16-19 16-19 16-19 13-15 11-16 16-17 Data collection 2010-2011 2013-2014 2011 2011 2011 2011 2012 2013 2014 2014 2012-2013 2013 2014 2015 2013-2014 2014 2014 2014 Country Poland Poland Korea US (Florida) US (Florida) US NYTS US NYTS US (Florida) US (Florida) US (Florida) China (Hong Kong) Italy Italy Italy UK (Scotland) UK (Wales) Greece Ireland Author Poland Goniewicz Goniewicz Subtotal (I^2 = 100.0%, p 0.0) Korea Lee US Porter Porter Dutra Dutra Barnett Porter Porter Subtotal (I^2 = 99.6%, p 0.0) China (Hong Kong) Wang Italy Gallus Gallus Gallus Subtotal (I^2 = 0.0%, p 0.8) UK SALSUS Moore Subtotal (I^2 = 0.0%, p 0.6) Greece Fotiou Ireland Babineau Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.7%, p 0.0); Figure 22: Pooled analyses of current e-cigarette use among smoking youth by country (2010-2015) country by youth smoking among use e-cigarette current of analyses Pooled 22: Figure e-cigarette ever of association assessing studies longitudinal for ratio odds adjusted Pooled 23: Figure uptake cigarette tobacco with baseline at non-smokers among use This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO. ES (95% CI) ES (95% CI) 15.3 (14.3, 16.4) 15.3 (14.3, 16.4) 57.4 (53.8, 61.0) 57.4 (53.8, 61.0) 20.0 (19.0, 21.1) 20.0 (19.0, 21.1) 36.6 (35.5, 37.7) 36.6 (35.5, 37.7) 18.9 (14.3, 24.3) 18.9 (14.3, 24.3) 18.4 (15.7, 21.2) 18.4 (15.7, 21.2) 9.8 (7.8, 12.1) 9.8 (7.8, 12.1) 26.5 (23.6, 29.5) 26.5 (23.6, 29.5) 2.7 (1.7, 4.0) 2.7 (1.7, 4.0) 44.8 (41.8, 47.9) 44.8 (41.8, 47.9) 51.7 (49.8, 53.5) 51.7 (49.8, 53.5) 22.4 (8.8, 40.0) 22.4 (8.8, 40.0) 4.4 (3.8, 5.0) 4.4 (3.8, 5.0) 11.1 (2.4, 29.2) 11.1 (2.4, 29.2) 7.1 (0.2, 33.9) 7.1 (0.2, 33.9) 5.3 (0.1, 26.0) 5.3 (0.1, 26.0) 8.1 (1.8, 17.1) 8.1 (1.8, 17.1) 9.9 (8.8, 11.1) 9.9 (8.8, 11.1) 15.3 (12.1, 18.9) 15.3 (12.1, 18.9) 10.6 (9.6, 11.8) 10.6 (9.6, 11.8) 2.0 (0.7, 4.7) 2.0 (0.7, 4.7) 10.6 (6.2, 16.6) 10.6 (6.2, 16.6) 17.4 (9.9, 26.4) 17.4 (9.9, 26.4) 80 60
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0 Outcome (n) 725 430 2672 48 147 76 230 24 481 1481 218 3 1 1 252 71 5 16 N 4738 749 7302 254 801 778 869 896 1073 2865 4978 27 14 19 2543 465 244 151 Age range 15-24 15-19 13-18 11-14 15-18 11-18 11-18 11-18 11-14 15-18 12-18 16-19 16-19 16-19 13-15 11-16 16-17 Data collection 2010-2011 2013-2014 2011 2011 2011 2011 2012 2013 2014 2014 2012-2013 2013 2014 2015 2013-2014 2014 2014 2014 Country Poland Poland Korea US (Florida) US (Florida) US NYTS US NYTS US (Florida) US (Florida) US (Florida) China (Hong Kong) Italy Italy Italy UK (Scotland) UK (Wales) Greece Ireland Author Poland Goniewicz Goniewicz Subtotal (I^2 = 100.0%, p 0.0) Korea Lee US Porter Porter Dutra Dutra Barnett Porter Porter Subtotal (I^2 = 99.6%, p 0.0) China (Hong Kong) Wang Italy Gallus Gallus Gallus Subtotal (I^2 = 0.0%, p 0.8) UK SALSUS Moore Subtotal (I^2 = 0.0%, p 0.6) Greece Fotiou Ireland Babineau Heterogeneity between groups: p = 0.000 Overall (I^2 = 99.7%, p 0.0); Figure 23: Pooled adjusted odds ratio for longitudinal studies assessing association of ever e-cigarette e-cigarette ever of association assessing studies longitudinal for ratio odds adjusted Pooled 23: Figure uptake cigarette tobacco with baseline at non-smokers among use
85 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review DISCLAIMER
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