Youth tobacco product use in the United States

Behavioral precursors of nicotine product use trajectories among youth

INTRODUCTION

Preventing nicotine use among youth is a public health priority. Nicotine use emerges from complex relationships between numerous factors. This project used network analysis to model behavioral precursors of nicotine use (knowledge, attitudes, perceptions, intentions) among youth who had never used nicotine and determine which predicted future trajectories of use across multiple nicotine products.

METHODS

Data were from the Population Assessment of Tobacco and Health study (2013-2018; analyzed 2023-2024), youth ages 12-17, who reported never using nicotine at Wave 1. Network structure was determined for behavioral precursors at Wave 1 and central network nodes were identified (N=5087). Central nodes were then tested as predictors of trajectories of use across multiple nicotine products during Waves 1-4 (N=3851).

RESULTS

Central nodes of the Wave 1 network were harm perception, expectancy that tobacco would calm anger/reduce stress, and intention to try. Those with lower intent to try at Wave 1 had lower odds of being in an Experimentation or Use class vs a Nonuse class during Waves 1-4 (p<.0001). Those with more accurate harm perception had lower odds of being in an Experimentation vs Non-use class (p=.004). Those with positive expectancies had higher odds of being in an Experimentation vs Non-use or Use class (p=.04,.02).

CONCLUSIONS

Findings suggest a network model of behavioral precursors of nicotine use that can be tested, including central nodes that predicted trajectories of use across multiple nicotine products, and therefore may be priority intervention targets.

The Burden and Correlates of Waterpipe (Hookah) Smoking among Adolescents and Youth: A Systematic Review

BACKGROUND

This systematic review evaluated the available medical literature on the prevalence and trends of waterpipe tobacco smoking among adolescents and youth in jurisdictionally representative populations.

METHODS

PubMed, Embase, and Scopus were searched for relevant studies from inception until 31 December 2022 that reported the burden of waterpipe smoking among adolescents and youth (10-24 years of age). We extracted qualitative data on the demographic characteristics, burden, and correlates of waterpipe smoking (PROSPERO ID: CRD42022310982).

RESULTS

A total of 2,197 articles were screened and 62 were included in the analysis. The majority (29) of the studies was from the United States of America and there were no studies from the south-east Asian region. The prevalence of ever waterpipe smoking among the 10-24 years age group was noted to be 18.16% (95% CI, 18.03-18.29). The prevalence of current (30-day) waterpipe smoking was 6.43% (95% CI, 6.34-6.50). The age of initiation of waterpipe smoking was variable. The prevalence of waterpipe smoking was higher among males, among those who belong to the high- and middle-income groups, and among university students. The common risk factors of waterpipe smoking included cigarette smoking, alcohol, and substance use. Waterpipe smoking resulted in increased susceptibility to the use of conventional forms of tobacco (e.g. smoking) among those who were never smokers.

CONCLUSION

Waterpipe smoking usage was significantly high among adolescents and young adults. Developing regulatory guidelines for water-pipe smoking, surveillance of its use, intervention, and specific policy frameworks may be considered a public health priority.

Temporal Trends in Tobacco Product Use Among US Middle and High School Students: National Youth Tobacco Survey, 2011-2020

OBJECTIVES

Despite significant declines in cigarette smoking during the past decade, other tobacco products gained popularity among middle and high school students. This study examined temporal trends in exclusive and concurrent use of tobacco products among middle and high school students in the United States from 2011 through 2020.

METHODS

We used multiple annual datasets from the National Youth Tobacco Survey from 2011 through 2020 (N = 193 350) to examine trends of current (past 30 days) exclusive, dual, and poly use of tobacco products (ie, cigarettes, electronic cigarettes [e-cigarettes], cigars, hookahs, and smokeless tobacco). We used joinpoint regression models to calculate log-linear trends in annual percentage change (APC).

RESULTS

During 2011-2020, exclusive use of any tobacco product decreased significantly, except for e-cigarettes, which increased significantly at an APC of 226.8% during 2011-2014 and 14.6% during 2014-2020. This increase was more pronounced among high school students (APC = 336.6% [2011-2014] and 15.7% [2014-2020]) than among middle school students (APC = 10.4% [2014-2020]) and among male students (APC = 252.8% [2011-2014] and 14.8% [2014-2020]) than among female students (APC = 13.6% [2014-2020]). During 2011-2020, we also found upward trends in dual use of e-cigarettes and cigarettes (APC = 17.3%). Poly use of e-cigarettes, cigarettes, and any other tobacco products increased significantly at an APC of 57.1% during 2011-2014.

CONCLUSIONS

The emergence of new tobacco products such as e-cigarettes in the US market has shifted the landscape of tobacco use among adolescents in the last decade toward poly product use, in which e-cigarettes are a prominent component. Our findings underscore the increasing complexity of tobacco use among adolescents in the United States and the need for strong policies and regulations adapted to evolving trends in cigarette and noncigarette tobacco products.

Electronic cigarette use by and perceptions of middle and high school students in the United States

Electronic cigarettes (e-cigarettes) provide a novel source of nicotine and may lead to experimentation by adolescents and eventually to their use of conventional cigarettes. The National Youth Tobacco Survey collected information from a nationally representative sample of students in 2016 to determine their experiences with conventional cigarettes and e-cigarettes, their intentions to use these products in the future, and their perceptions of harm and addiction associated with these products. We analyzed these data with ordered probit regression models to determine possible associations with the intention to try e-cigarettes and conventional cigarettes. This survey included 20,520 respondents, 50.6% were male, 5.9% had used conventional cigarettes, and 9.0% had used e-cigarettes. Approximately 10% thought e-cigarettes caused no harm, 3.7% thought that conventional cigarettes caused no harm, and 52.5% thought that e-cigarettes were less harmful than conventional cigarettes. Less than 1% of the students responded "Definitely yes" to the question, "Do you think you will try an e-cig?" The odds ratios for an intention to try e-cigarettes increased as the perception of harm decreased; these ratios increased from 1.0 for "A lot of harm" to 5.85 (95% CI: 3.51, 9.75) for "No harm." In 2016, the majority of students thought that e-cigarettes could cause some harm. This survey indicates that most students have not tried e-cigarettes or conventional cigarettes. The minority of students who think that e-cigarettes pose no harm and students in the ages 14 and 16 are more likely to try them.

Determinants of E-Cigarette and Cigarette Use among Youth and Young Adults in Poland-PolNicoYouth Study

Teen use of tobacco-related products is a significant public health concern. This study evaluated the predictors of e-cigarette use among secondary school students who were never cigarette smokers and ever cigarette smokers in Poland.

METHODS

This study examined a sample of Polish youths aged 13-19 (n = 19,241) attending 200 schools, 12 on average in each county. The study was a part of the National Health Program in Poland for 2016-2020. Logistic regression and multivariable logistic regression models were used to calculate crude and adjusted odds ratios.

RESULTS

Of all participants, 32.5% were ever cigarette users. Among the never cigarette users, 13.6% were deemed susceptible to e-cigarette use. Among the ever cigarette users, 60.6% were deemed susceptible to e-cigarette use. Of those susceptible to e-cigarette use, 68.2% were among the 32.5% ever cigarette users. The profile of e-cigarette use among never e-cigarette users also included: pocket money available per month (more than 150 PLN) (OR = 1.7; p = 0.001), 16-17 years old (OR = 1.9; p = 0.001), parental tobacco smoking and e-cigarette usage (OR = 2.0; p = 0.01 and OR = 1.7; p = 0.001 respectively), maternal secondary education (OR = 1.1; p = 0.04), and living in big cities >500,000 inhabitants (OR = 1.4; p = 0.04). E-cigarette users among ever cigarette users were similar to never cigarette users in their opinion that e-cigarette use is less harmful than traditional smoking (OR = 1.6; p = 0.0012) and living with both parents smoking cigarettes (OR = 1.3; p = 0.02). Additionally, the determinants were: female gender (OR = 1.5; p = 0.009) in the age group less than 15 years of age (OR = 1.3; p = 0.007).

CONCLUSIONS

The major determinant of e-cigarette use in this population was prior smoking. Additionally, the results revealed that fairly obvious predictors such as parental smoking and a belief in the less harmfulness of e-cigarette use are important determinants for smoking among never or ever e-cigarette users.

Correlates of youth Poly-E-Cigarette device use

PURPOSE

The objective of this study was to examine poly-e-cigarette (poly-EC) device use among youth EC users and identify factors associated with poly- versus single-EC device use status.

METHODS

861 EC users aged 14-21 responded to an online survey about EC use and sociodemographic factors in August 2020. Respondents were included if they were current EC users (i.e., at least one day in the past 30 days) and excluded if they were currently using other tobacco products (OTPs).

RESULTS

Data analysis indicated poly-EC device use was associated with higher self-reported nicotine dependence, younger age of onset, having close friends who use ECs and higher or lower self-perceived socioeconomic status compared to others.

CONCLUSIONS

Young poly-EC device users were more likely to begin using at a younger age, live with and have close friends who were EC users, and report greater nicotine dependence. Identifying temporality in these associations can identify youth at greater risk of poly-EC use. Future research should examine poly-EC device use in prospective surveillance monitoring to further evaluate the longitudinal implications on use and dependence.

Use of Tobacco and Nicotine Products among Young People in Denmark-Status in Single and Dual Use

Lots of new tobacco or nicotine products are being launched, e.g., e-cigarettes and smokeless tobacco, which appeal especially to the youngest part of the population. For example, the use of smokeless tobacco among Danish youth rose from approx. 2% in 2010 to 9% in 2020. Hence, there is an urgent need to follow and intervene against youth tobacco or nicotine product use. This study explored the current use of cigarettes, e-cigarettes, heated tobacco, and smokeless tobacco among Danish 15- to 29-year-olds. Further, we examined the concurrent use of two products or more. We used a nationwide survey conducted among 15- to 29-year-olds in February and March 2020. Overall, approx. 35,700 individuals received the questionnaire of which 35.5% responded (n = 13,315). One out of five (20.1%) smoked cigarettes, half of them daily, the other half occasionally. About one in twenty (3.9%) used e-cigarettes (daily or occasionally), and more than one in three (31.6%) had tried e-cigarettes. The use of heated tobacco among Danish youth is still relatively limited (0.3%). In comparison, about 9% used smokeless tobacco (daily or occasionally). Overall, 27.0% stated that they use at least one type of tobacco or nicotine product, while 5.6% used more than one product. Monitoring tobacco-related behavior in youth provides extremely important information for, e.g., policymakers and health professionals.

Multiple tobacco product use among cigarette smokers: a longitudinal examination of menthol and non-menthol smokers during young adulthood

BACKGROUND

Multiple tobacco product (MTP) use is common among young adults. Most MTP users are combustible cigarette smokers that use one or more other tobacco products. This study aims to explore menthol as a risk factor for MTP use among a cohort of young adult cigarette smokers.

METHODS

Participants were 18-29 years cigarette smokers at 24 Texas colleges in a 6-wave study. Participants (n=4700 observations) were classified as: single product users (ie, exclusive cigarette smoking); dual product users and poly product users. A multilevel, ordered logistic regression model was used to examine the association between menthol cigarette smoking and MTP use. Two longitudinal, multilevel, multinomial logistic regressions were used to examine the relationship between menthol cigarette smoking and number of tobacco products used.

RESULTS

Overall, 40.7% of the sample were single product users, 33.7% were dual product users and 25.6% were poly product users. Menthol was associated with 1.28 greater odds of MTP use. Further, menthol was associated with 1.19 greater risk of dual and 1.40 greater risk of poly product use, relative to single product use. Lastly, menthol cigarette smoking was associated with 1.18 greater risk of poly product use, relative to dual product use.

CONCLUSIONS

There was a gradient relationship between menthol cigarette smoking and number of tobacco products used among young adult cigarette smokers. Findings provide for greater regulatory and programmatic efforts to reduce the use of menthol cigarettes.

Responses to Gradual and Immediate Reduction of Nicotine in Cigarettes in Young Versus Older Adult Smokers

INTRODUCTION

As the FDA works to determine whether a nicotine reduction policy would benefit public health, one key question is whether to mandate an immediate or gradual reduction in nicotine levels in cigarettes. The aim of this study was to determine whether the effects of gradual versus immediate nicotine reduction on cigarettes per day (CPD), total nicotine equivalents, and subjective responses differed in younger adults versus older adults.

METHODS

Using data from a recent randomized trial conducted in the United States (N = 1250) that switched smokers over a 20-week period to very low nicotine content (VLNC) cigarettes either immediately, gradually (via monthly reductions in nicotine content), or not at all (control condition, normal nicotine content research cigarette), we analyzed the moderating effect of age (age 18-24 or 25+).

RESULTS

For both age groups, CPD in the immediate condition was significantly lower relative to gradual condition (estimated mean difference of 6.3 CPD in young adults, 5.2 CPD in older adults; p's < .05). Younger and older adults in the immediate and gradual reduction conditions had lower total nicotine equivalents at Week 20 (all p's < .05) than those in the control condition; age group did not moderate this effect. Positive subjective responses to cigarettes were lower among young adults relative to older adults in the immediate condition.

CONCLUSIONS

These results indicate that an immediate reduction in nicotine would result in beneficial effects in both young and older adults. Young adults show less positive subjective effects of smoking following switching to VLNC cigarettes relative to older adults.

IMPLICATIONS

As researchers work to understand how a potential reduced-nicotine product standard for cigarettes may affect public health, one question is whether nicotine should be reduced immediately or gradually. This study demonstrates that both young and older adults who were switched immediately to the lowest content of nicotine smoked fewer CPD and had lower nicotine intake than those in the gradual condition. Furthermore, young adults appear to show lower positive subjective effects following switching to VLNC cigarettes relative to older adults. This is consistent with previous work demonstrating that young people appear to show lower abuse liability for VLNC cigarettes.

Heterogeneities in administration methods among cannabis users by use purpose and state legalization status: findings from a nationally representative survey in the United States, 2020

BACKGROUND AND AIMS

Different cannabis administration methods have differential impacts on health. This study aimed to describe administration methods among cannabis users in the United States categorized by (1) use purpose and (2) state legalization status.

DESIGN

Cross-sectional, probability-based online survey in 2020.

SETTING

All 50 states and Washington DC in the United States.

PARTICIPANTS

A total of 21 903 adults (18+) were recruited from a probability-based online panel to provide nationally representative estimates.

METHODS

Eleven administration methods were grouped into combustion, vaporization, ingestion and topicals. Weighted prevalence was reported among (1) medical-only, recreational-only and dual-purpose users based on self-reported purposes and (2) users in states that legalized both recreational and medical cannabis (RCL states), legalized medical cannabis only and did not legalize cannabis.

FINDINGS

Among past-year users, the proportions of medical-only, recreational-only and dual-purpose users were 25.55, 43.81 and 30.64%, respectively. The most common primary methods were combustion (42.08%) and topicals (28.65%) for medical purposes and combustion (72.07%) and ingestion (15.05%) for recreational purposes. Dual-purpose users were more likely to report combustion and vaporization but less likely to report ingestion and topicals as primary methods for medical use than medical-only users (P < 0.001) and more likely to report combustion and topicals but less likely to report ingestion as primary methods for recreational use than recreational-only users (P < 0.041). A higher proportion of dual-purpose users (82.82%) used more than one method than medical-only (40.52%) and recreational-only users (63.91%) (P < 0.001). For both medical and recreational purposes, RCL states had the lowest rate of combustion and the highest rates of ingestion and topicals reported as primary methods (P < 0.033). The rate of using more than one administration method did not differ across states (P > 0.05).

CONCLUSION

Cannabis users whose purposes are medical, recreational or both tend to differ in their selected administration methods.

Tobacco and Nicotine Use Among US Adult "Never Smokers" in Wave 4 (2016-2018) of the Population Assessment of Tobacco and Health Study

INTRODUCTION

A common criterion for being labeled a "never smoker" is having smoked <100 lifetime cigarettes. This category is often used as an unexposed reference group to estimate the relative harm from cigarettes. We examined the amount of current and past cigarette and non-cigarette tobacco/nicotine use among adults who met this "never smoker" criterion.

METHODS

We analyzed cross-sectional data from 17 179 adult "never smokers" (ie, reported <100 lifetime cigarettes) in Wave 4 (2016-2018) of the Population Assessment of Tobacco and Health (PATH) Study, a United States nationally representative sample. We used PATH-derived variables to describe "never smokers'" demographics as well as cigarette and non-cigarette tobacco/nicotine use.

RESULTS

Approximately half of "never smokers" were young adults (49.3%). Most were white (68.6%) with some college or more (64.4%). Most "never smokers" had tried any cigarette or non-cigarette tobacco/nicotine in their lifetime (66.7%), 8.5% smoked cigarettes in the past 30 days, and 5.3% were current experimental (ie, some days or every day) cigarette smokers. By definition, "never smokers" reported smoking <100 lifetime cigarettes. One fifth (22.8%) had a lifetime history of established regular non-cigarette tobacco/nicotine use and 8.6% were current established regular non-cigarette tobacco/nicotine users. In total, 9.4% of "never smokers" were current experimental or established regular users of combustible tobacco.

CONCLUSIONS

The 100-cigarette lifetime threshold includes substantial amounts of current and past tobacco use and thus does not represent lack of exposure to cigarette or non-cigarette tobacco. "Never smoker" reference groups may produce underestimates of the relative harms from cigarettes.

IMPLICATIONS

The <100 lifetime cigarettes criterion may not capture what many would consider true "never smokers." Relying on the current definition of "never smokers" as a reference group will include a substantial number of those currently and recently using combustible tobacco and thus produce data that may underestimate the relative harm from cigarettes. Prospective longitudinal research is needed to compare how the 100-cigarette lifetime threshold versus other definitions of regular cigarette smoking differ in predictive validity of clinically meaningful outcomes and health harms to determine the optimal criteria to define established cigarette smoking.

Longitudinal pathways of exclusive and polytobacco cigarette use among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

Cigarettes are the most harmful and most prevalent tobacco product in the USA. This study examines cross-sectional prevalence and longitudinal pathways of cigarette use among US youth (12-17 years), young adults (18-24 years) and adults 25+ (25 years and older).

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US adults and youth. Respondents with data at all three waves (youth, N=11 046; young adults, N=6478; adults 25+, N=17 188) were included in longitudinal analyses.

RESULTS

Among Wave 1 (W1) any past 30-day (P30D) cigarette users, more than 60%, persistently used cigarettes across three waves in all age groups. Exclusive cigarette use was more common among adult 25+ W1 P30D cigarette users (62.6%), while cigarette polytobacco use was more common among youth (57.1%) and young adults (65.2%). Persistent exclusive cigarette use was the most common pathway among adults 25+ and young adults; transitioning from exclusive cigarette use to cigarette polytobacco use was most common among youth W1 exclusive cigarette users. For W1 youth and young adult cigarette polytobacco users, the most common pattern of use was persistent cigarette polytobacco use.

CONCLUSIONS

Cigarette use remains persistent across time, regardless of age, with most W1 P30D smokers continuing to smoke at all three waves. Policy efforts need to continue focusing on cigarettes, in addition to products such as electronic nicotine delivery systems that are becoming more prevalent.

Personal and perceptual factors associated with the use of electronic cigarettes among university students in northern Thailand

INTRODUCTION

Although Thailand has banned the import of electronic cigarettes (e-cigarettes) into the kingdom, a range of evidence has revealed the widespread use of these illegal products, especially among university students. Too little is known about personal and perceptual factors for such behavior. This study aimed to investigate the prevalence and factors associated with the use of e-cigarettes among university students in Northern Thailand

METHODS

A cross-sectional study was conducted with 792 university students in Northern Thailand between June and July 2020. An anonymous, self-administered questionnaire was implemented to collect relevant information. Bivariate and multivariate logistic regression analyses were applied to identify factors associated with the use of e-cigarettes in the last 30 days.

RESULTS

The study revealed that 18.1% of the participants used e-cigarettes in the past 30 days. The personal factors associated with e-cigarette use among Thai university students included: studying in non-health related faculties (AOR=11.21; 95% CI: 4.88–25.71); having a friend using e-cigarettes (AOR=10.48; 95% CI: 5.96–18.41); having a lower GPA than the mean (AOR=1.93; 95% CI: 1.14– 3.28); and having a monthly income higher than the mean (AOR=1.74; 95% CI: 1.09–2.78). Regarding perceptual factors, there was a significant link between e-cigarette use and the perception that these modern cigarettes are less harmful than conventional cigarettes (AOR=2.47; 95% CI: 1.50–4.07), and perception that using e-cigarettes in public is not illegal (AOR=1.93; 95% CI: 1.19–3.15).

CONCLUSIONS

E-cigarette use is widespread among Thai university students. Maintaining the enforcement policy on banning the importation of e-cigarettes into the country is thus needed. Also, further communication and public relations on the risks and legal prohibitions of e-cigarette use are needed among university students in the Northern Thailand.

Developmental patterns of tobacco product and cannabis use initiation in high school

AIMS

To identify prototypical developmental patterns of tobacco product and cannabis use and co-use initiation during adolescence, and determine risk factors for and consequences of these initiation patterns.

DESIGN

Prospective repeated-measures cohort with eight semi-annual assessments during high school. Multiple-event process survival mixture modeling identified latent initiation classes with distinct patterns of variation in timing of use initiation of tobacco products and cannabis. We then estimated: (1) associations of baseline risk factors with membership in initiation classes and (2) differences between initiation classes in frequency of cannabis and tobacco product use at the final assessment.

SETTING

Ten high schools in the Los Angeles, CA, USA metropolitan area, 2013-17.

PARTICIPANTS

Students [1031 (45.4%) males; mean (standard deviation) age at baseline = 14.6 (0.39) years] who had never used any tobacco products or cannabis at baseline 9th grade assessment (n = 2272).

MEASUREMENTS

Self-report measures of electronic cigarette (e-cigarette), combustible cigarette, hookah, cigar/cigarillos and cannabis use were collected at each assessment.

FINDINGS

Four distinct tobacco and cannabis use initiation classes were identified: (1) early and high-risk cannabis and polytobacco initiators (n = 116; 5.1%); (2) early cannabis and polytobacco initiators (n = 172; 7.6%); (3) late cannabis and e-cigarette initiators (n = 431; 19.0%); and (4) abstainers (n = 1553; 68.4%). At baseline, older age for the early and high-risk cannabis and polytobacco initiators [odds ratio (OR) = 1.22, 95% confidence interval (CI) = 1.10, 1.35, P < 0.001], peer cannabis use (OR = 1.60, 95% CI = 1.23, 2.08, P < 0.001) and delinquent behavior (OR = 1.30, 95% CI = 1.08, 1.55, P = 0.004) were associated with membership in the three initiation classes (versus abstainers). Membership in the early and high-risk cannabis and polytobacco initiators class (versus three other classes) was significantly associated with increased past 30-day frequency and daily intensity of use at the final assessment (P-values < 0.001).

CONCLUSIONS

Older age, peer cannabis use and delinquent behavior appear to be risk factors for the initiation of tobacco/cannabis product use among high school students in the Los Angeles metropolitan region. Early and higher-risk polyproduct use initiation appears to be associated with greater escalation of past 30-day and daily tobacco and cannabis use at the end of the high school.

Predicting the mortality of smoking attributable to cancer in Qingdao, China: A time-series analysis

Smoking is the leading preventable cause of death and disability from cancer in China. To provide a scientific basis for tobacco control strategies and measures, this study investigated cancer deaths attributed to smoking from 2005 to 2017 and predicted mortality trends from 2018 to 2020 in Qingdao. We used time series analysis to evaluate the number of deaths attributed to smoking among residents over 35 years old in Qingdao and predicted mortality trends. The number of cancer deaths attributed to smoking in Qingdao from 2005 to 2016 was between 170 and 407, showing an upward trend and a certain periodicity. The best model is the ARIMA (2,1,0)×(3,1,0)₁₂, with the lowest BIC (6.640) and the highest stationary R² (0.500). The predicted cancer deaths curve attributed to smoking in 2017 is consistent with the actual curve, with an average relative error of 5.74%. Applying this model to further predict the number of cancer deaths attributed to smoking in Qingdao from January 2018 to December 2020, the predicted results were 5,249, 5,423 and 6,048, respectively. The findings emphasized the need to further strengthen tobacco control measures to reduce the burden of disease caused by tobacco.

Financial Literacy, Financial Education, and Smoking Behavior: Evidence From Japan

In this study, we examine the relationship between financial literacy, financial education, and smoking behavior among the Japanese population. We hypothesize that financially literate and financially educated people, who have the ability to make more rational decisions, are less likely to smoke. Using the Preference Parameters Study of Osaka University, conducted in 2010 (N = 3,706), the probit regression results show that both financial literacy (with an emphasis on knowledge of investments) and financial education (with an emphasis on savings behavior) have a significant negative impact on smoking behavior. In addition, gender, age, education, marital status, household income and assets, risky behaviors, a myopic view of the future, risk preference, and level of happiness also significantly predict the likelihood of a person being a current smoker. This study provides empirical evidence that enhancing the rational decision-making ability of individuals through financial literacy and financial education may curtail smoking behavior.

Cigarillo and multiple tobacco product use and nicotine dependence in adolescents and young adults

INTRODUCTION

Multiple tobacco product (MTP) use is a growing public health concern, particularly among adolescents and young adults. This study identifies subgroups of MTP use among cigarillo users and examines associations with nicotine dependence (ND).

METHODS

1089 youth (ages 14-28) who currently smoke cigarillos completed a web-based survey regarding their current use of cigarillos, little cigars, traditional cigars, cigarettes, e-cigarettes, and waterpipe/hookah. Latent class analysis (LCA) was used to identify patterns of product use by type and amount. The LCA also assessed the relationship between the latent classes and a 38-item measure of ND, controlling for relevant demographics.

RESULTS

Most participants (88.2%) reported using two or more tobacco products in the past 30 days. The best-fitting LCA solution revealed 7 classes: (1) Mixed-Light tipped cigarillo and light cigarette users, 28.9%; (2) Light tipped cigarillo users, 15.8%; (3) Light untipped cigarillo users, 14.3%; (4) Heavy tipped cigarillo users, 13.4%; (5) E-cigarette and waterpipe users, 11.9%; (6) Heavy users of tipped and untipped cigarillos and light users of cigarettes, 9.8%; and (7) Dabblers who primarily used traditional cigars, but were also likely to use a variety of other products, 6.1%. Classes comprised of those using multiple products-particularly those that included cigarettes-had significantly higher levels of ND than other classes (Tukey's HSD P < .05).

CONCLUSIONS

Distinct patterns of MTP use are evident among young cigarillo smokers. Smoking multiple products, particularly smoking cigarillos in combination with cigarettes, is associated with higher ND compared to other product use patterns.

Patterns of tobacco use and nicotine dependence among youth, United States, 2017-2018

This study examined patterns of tobacco product use and their association with nicotine dependence among U.S. youth. Combined data from the 2017-2018 National Youth Tobacco Surveys were analyzed for students that reported current (past-30-day) use of e-cigarettes, cigarettes, cigars, smokeless tobacco, or hookah (n = 6106). Analyses assessed multiple product use (≥2 tobacco products) overall and by sex, school level, race/ethnicity, current use, and frequent use (use of a product for ≥20 of the preceding 30 days). Multivariable logistic regression was used to identify correlates of nicotine dependence. During 2017-2018, 40.8% of tobacco product users reported use of multiple products. Multiple product use ranged from 47.0% among e-cigarette users to 80.7% among cigarette smokers. Among frequent users of each respective product, 80.0% of cigarette smokers, 74.9% of cigar smokers, 73.6% of smokeless tobacco users, 70.7% of hookah smokers, and 40.3% of e-cigarette users reported use of multiple products. Most youth who reported nicotine dependence (64.0%) were multiple product users. E-cigarettes were the most common single product used (36.3%) and the product most commonly used in combination with other products; e-cigarettes plus cigarettes (6.7%) was the most common product combination. Combustible product use, smokeless tobacco use, multiple product use and frequent use were associated with greater odds of nicotine dependence. Nicotine dependence among youth is especially influenced by cigarette use, smokeless tobacco use, frequent use of any tobacco product, and multiple product use. Proven tobacco control interventions in coordination with regulatory efforts can reduce youth tobacco product use.

Characterizing the polytobacco behaviors of sexual minority young adult college students

INTRODUCTION

Polytobacco use is a growing concern; users are exposed to cumulatively more nicotine, increasing their risk for dependence and long-term use. More sexual minority (SM) young adults report polytobacco use than their heterosexual peers, yet no studies explore how their tobacco patterns vary across the diverse product landscape. The purpose of this study was to characterize SM young adults' patterns of tobacco use and nicotine dependence, and explore co-occurring risk factors for polytobacco use.

METHODS

Participants were 609 SM Texas college students. Latent class analysis identified subgroups of tobacco users based on their tobacco use behaviors and an indicator of nicotine dependence. Multinomial logistic regression identified associations between individual-level variables and the probability of membership in various user classes.

RESULTS

Tobacco use clustered in four classes: non-users, non-addicted cigarette users, non-addicted e-cigarette users, and addicted polytobacco users. Polytobacco users had an increased probability of depressive symptoms and cannabis use relative to non-users, and more binge alcohol use than all other groups. Non-addicted cigarette users had an increased probability of binge alcohol use, cannabis use, and being non-Hispanic White relative to non-users, and an increased likelihood of cannabis use relative to non-addicted e-cigarette users. Non-addicted e-cigarette users had an increased probability of binge alcohol use relative to non-users.

CONCLUSIONS

SM young adults' tobacco use varies across the diverse product landscape. Failing to account for a range of tobacco behaviors and nicotine dependence prevents tailoring interventions that should also address concerns such as depressive symptoms, cannabis use, and binge alcohol use.

Initiation of any tobacco and five tobacco products across 3 years among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

This study reports weighted cross-sectional prevalence of never use of tobacco, and longitudinal past 12-month (P12M), past 30-day (P30D) and frequent P30D any tobacco or specific tobacco product initiation across three 1-year waves. Longitudinal three-wave pathways are examined to outline pathways of exclusive and polytobacco initiation, as well as pathways of new initiators of electronic nicotine delivery systems (ENDS) or cigarettes.

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth and adults. Respondents with data at all three waves (youth, N = 11 046; young adults, N = 6478; adults 25+, N = 17 188) were included in longitudinal analyses.

RESULTS

Across the three age groups, weighted cross-sectional analyses revealed never any tobacco use decreased each year from 2013 to 2016, reflecting overall increases in tobacco initiation in the population during this time. Compared with cigarettes, cigars, hookah and smokeless tobacco, ENDS had the highest proportion of P12M initiation from Wave 1 to Wave 3 (W3) for each age group. Among youth Wave 2 P30D initiators of exclusive ENDS or cigarettes, the most common W3 outcome was not using any tobacco (ENDS: 59.0% (95% CI 48.4 to 68.8); cigarettes: 40.3% (95% CI 28.7 to 53.1)).

CONCLUSIONS

Initiation rates of ENDS among youth and young adults have increased the number of ever tobacco users in the US prevention strategies across the spectrum of tobacco products which can address youth initiation of tobacco products.

Longitudinal transitions of exclusive and polytobacco electronic nicotine delivery systems (ENDS) use among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

Electronic nicotine delivery systems (ENDS; including e-cigarettes) are rapidly evolving in the US marketplace. This study reports cross-sectional prevalence and longitudinal pathways of ENDS use across 3 years, among US youth (12-17 years), young adults (18-24 years) and adults 25+ (25 years and older).

DESIGN

Data were from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth and adults. Respondents with data at all three waves (youth, n=11 046; young adults, n=6478; adults 25+, n=17 188) were included in longitudinal analyses.

RESULTS

Weighted cross-sectional ever use of ENDS increased at each wave. Across all three waves, young adults had the highest percentages of past 12-month, past 30-day (P30D) and daily P30D ENDS use compared with youth and adults 25+. Only about a quarter of users had persistent P30D ENDS use at each wave. Most ENDS users were polytobacco users. Exclusive Wave 1 ENDS users had a higher proportion of subsequent discontinued any tobacco use compared with polytobacco ENDS users who also used cigarettes.

CONCLUSIONS

ENDS use is most common among young adults compared with youth and adults 25+. However, continued use of ENDS over 2 years is not common for any age group. Health education efforts to reduce the appeal and availability of ENDS products might focus on reducing ENDS experimentation, and on reaching the smaller subgroups of daily ENDS users to better understand their reasons for use.

Using a classification tree modeling approach to predict cigarette use among adolescents in the United States

Objective: The purpose of this study was to screen pertinent variables to identify ordered relations that provide easily interpretable and accurate predictions of the probability of cigarette use among adolescents using a classification tree modeling approach. Methods: This cross-sectional study included a national sample of 3717 U.S. adolescents aged between 12 and 20 years old from the 2016 National Survey on Drug Use and Health. Results: The results indicated that age was the most influential variable, followed by depression, race/ethnicity, family income, gender, and alcohol abuse and dependence. Additionally, several interaction emerged that identified higher and lower cigarette use profiles: youth who were between 18 and 20 years old and self-identified as non-Hispanic White, Native American/Alaska Native, and "Other" racial/ethnic group and African American, Asian, and Latinx adolescents, with depressive symptoms were at higher risk of cigarette use; while youth who reported lower family incomes, were 16-17 years old, who identified as African American, Asian, and Latinx, were also likely to report lower use of cigarettes when they reported lower depressive symptom scores. Discussion: These results are discussed relative to practice implications.

Poly-Tobacco Use among Young Adult Waterpipe Smokers: Insights from University Students in Three Eastern Mediterranean Countries

INTRODUCTION

There is a tendency of waterpipe smokers to advance their practice toward concurrent use (poly-tobacco use) of other tobacco products and nicotine delivery systems. This study investigated poly-tobacco use among waterpipe smokers, and its effect on their quit intention.

METHODS

Descriptive cross-sectional design was utilized to recruit a convenience sample of university students who used waterpipe in three East Mediterranean countries. Using an internet-based survey, data were collected regarding participants' demographics, use of alternative tobacco products and nicotine delivery systems, and waterpipe quitting profile. Results: A total of 2290 students agreed to participate, among which 1116 (45.3%) reported using at least one tobacco product beside waterpipe. Poly-tobacco use was highest (61.1%) in Egypt, followed by Jordan (45.1%) and Palestine (33.1%). Across countries, cigarettes were the most common product (45.2%, n = 924) followed by cigar (18.6%, n = 374) and e-shisha (17.5%, n = 353). Conversely, the least reported product was smokeless tobacco (7.5%, n = 151) preceded by regular pipe (9.5%, n = 193). Participants who were males (OR = 2.83, 95% CI: 2.18-3.65), older (22-29 years) (OR = 1.15, 95% CI: 1.09-1.22), unemployed (OR = 1.58, 95% CI: 1.22-2.04), and those who initiated waterpipe at a younger age (OR = 0.87, 95% CI: 0.87-0.91) had higher odds of being poly-smokers. Poly-tobacco users were significantly more resistant to quit waterpipe. Conclusion: This study demonstrates poly-tobacco use as a rising phenomenon among waterpipe smokers and highlights the necessity for initiating advanced interventions to help waterpipe poly-tobacco users quit this dangerous type of addiction. Various country-specific programs are needed considering the various products used by the users.

Anticipated Effects of Nicotine Reduction on Youth Smoking Initiation and Maintenance

This commentary summarizes emerging findings on the potential impact of a nicotine reduction policy on youth and young adults. We conclude that: (1) adolescent smokers and nonsmokers alike are likely to be less sensitive to reinforcement from very low nicotine content (VLNC) cigarettes compared with adults; (2) reducing nicotine in cigarettes to 0.4 mg/g would reduce the abuse potential of cigarettes in adolescents and young adults; (3) findings to date do not support concerns that nicotine reduction leads to compensatory smoking in young smokers; and (4) if the scope of a reduced nicotine product standard were applied to all combusted tobacco products, that would likely maximize public health benefit of this policy.

Risk factors for multiple tobacco product use among high school youth

PURPOSE

To examine how youth multiple tobacco product (MTP) users differ relative to non-users and to single-product users on risk factors at multiple levels of influence.

METHODS

We analyzed data on high school students from the North Carolina Youth Tobacco Survey, 2015 (n = 2922). Single- and MTP use were defined as use of one, or two or more tobacco products in the past month, respectively. Multinomial regressions estimated the association between risk factors and MTP use compared to single-product use and non-use of tobacco. Risk factors included intra-personal (e.g., harm perceptions), and interpersonal (e.g., household, peer tobacco use, secondhand smoke or vapor, and advertising) factors.

RESULTS

Of students, 12% and 13% were single product and MTP users, respectively. Many differences emerged between MTP users and non-tobacco users, with MTP users showing lower harm perceptions, higher perceived social benefits of smoking, significantly higher relative risk of having friends who use tobacco (RRR = 4.79, 95% CI 3.42, 6.70), of exposure to secondhand e-cigarette vapor (RRR = 1.35, 95% CI 1.23, 1.48), and of being receptive to tobacco marketing (RRR = 4.01, 95% CI 2.87, 5.61). Fewer differences emerged between MTP and single product users with MTP users having significantly higher relative risk of having friends who use tobacco (RRR = 2.31 95% CI 1.73, 3.07), of exposure to secondhand vapor (RRR = 1.10, 95% CI 1.02, 1.18), and of being receptive to tobacco marketing (RRR = 1.71, 95% CI 1.17, 2.50).

CONCLUSIONS

Efforts that target multiple tobacco product use should increase youth tobacco-related harm perceptions, and protect youth from social, peer, and industry influences.

Hookah Use Among US Youth: A Systematic Review of the Literature From 2009 to 2017

INTRODUCTION

Given the US Food and Drug Administration (FDA)'s authority to regulate hookah, more research is needed to inform regulations intended to prevent youth from using hookah. This systematic review summarizes and assesses the literature related to hookah use among adolescents (11 to ≤18 years of age) in the United States from 2009 to 2017.

METHODS

Database searches yielded 867 peer-reviewed articles. After duplicates were removed, authors reviewed 461 articles for inclusion. Included articles (n = 55) were coded for study themes, study quality, and their relevance to FDA's research priorities. A qualitative synthesis is presented.

RESULTS

The following themes were identified: (1) prevalence of hookah use (n = 42), (2) tobacco use transitions (n = 7), (3) sociodemographic correlates (n = 35), (4) psychosocial risk factors (n = 21), (5) concurrent use of other tobacco products (n = 31), (6) concurrent use of other substances (n = 9), and (7) other (n = 15)-which includes low prevalence themes. The qualitative synthesis showed increasing rates of hookah use. Older age, male gender, positive social normative beliefs, higher peer use, as well as lower perceived risk were associated with hookah use. Longitudinal studies of youth hookah use showed bidirectional relationships between use of hookah and other tobacco products. All articles fell within FDA's research priority related to "behavior," and three priorities ("impact analysis," "health effects," and "toxicity") have not been explored for hookah use among US youth since 2009.

CONCLUSIONS

The prevalence of hookah use among youth in the United States is increasing, thus more research is needed to inform policies targeted to protect this vulnerable population.

IMPLICATIONS

This study represents a novel contribution to our understanding of hookah use among youth in the United States from 2009-the year that the Family Smoking Prevention and Tobacco Control Act was passed-to 2017. In recent years, hookah has become a more popular tobacco product among US youth; however, to date, no systematic reviews of hookah use among this population exist. Results highlight implications for future US FDA regulatory policy and identify gaps in research to be addressed in future studies.

Predictors of E-Cigarette Use Susceptibility-A Study of Young People from a Socio-Economically Disadvantaged Rural Area in Poland

Identification of the youth at risk of e-cigarette use is crucial for development of effective prevention strategies. The current study aims at evaluation of predictors of susceptibility to e-cigarette initiation and experimentation among adolescents. This cross-sectional study included 1693 students (non-current users of e-cigarettes) attending 21 schools in Piotrkowski district (a socially disadvantaged rural area in central Poland). The regression models were applied so as to study factors linked to susceptibility to e-cigarette use among never users (n = 1054) and ever users (n = 639) of e-cigarettes, with susceptibility defined as the absence of a firm decision not to use these products. A high proportion of the youth was susceptible to e-cigarette use (68% of never and 78% of ever e-cigarette users). The adjusted model confirmed the following risk factors: smoking parents and friends (never users: OR = 3.0; p < 0.001; OR = 2.0; p < 0.05; ever users: OR = 2.2; OR = 2.2; p < 0.01), alcohol consumption (never users: moderate drinking OR = 2.9; p < 0.001; binge drinking OR = 2.2; p < 0.01; ever users: moderate drinking OR = 4.2; p < 0.001), cigarette smoking (never users: OR = 14.1; ever users: OR = 11.3; p < 0.001), and perception that e-cigarettes are less harmful than traditional cigarettes (never users: OR = 1.8; p < 0.001). The youth whose mothers had a medium and high educational level (never users: OR = 2.7; p < 0.01; OR = 2.7; p < 0.05; ever users: OR = 5.4; OR = 4.4; p < 0.001), those who perceived girls who use e-cigarettes as more attractive (never users: OR = 4.1; p < 0.001; ever users: OR = 2.9; p < 0.01), and secondary school students (ever users: OR = 5.6; p < 0.001) had higher odds of susceptibility to e-cigarette use. The youth who had more money per month were less susceptible to e-cigarette experimentation (OR = 0.4; p < 0.001). A multi-level intervention approach, considering vulnerable populations, is required to prevent the youth from e-cigarette initiation and experimentation.

Are parent involvement and school quality associated with adult smoking behaviors? Findings from an urban early childhood cohort

Although smoking prevention is a high priority, few studies have examined alterable family and school context factors in childhood that influence later smoking behaviors. The present study examined associations of parent involvement in and expectations for children's education, elementary school quality, and school mobility with lifetime smoking history in adulthood for a low-income, minority cohort. Participants from the Chicago Longitudinal Study (N = 1142) were interviewed at age 22-24 as part of a 20-year follow-up of a prospective early childhood cohort of economically disadvantaged families. The sample is 74% of the original cohort (N = 1539). Family surveys and school records measured parent involvement and expectations as well as school quality and mobility from 4th to 8th grades. At age 22-24 follow-up, 47% reported a smoking history, and 37% were current smokers. After controlling for family background and participant characteristics, parent involvement in school was associated with reduced odds of a smoking history (OR = 0.88; 95% CI = 0.78, 0.99). Magnet school attendance (a school quality indicator) was associated with lower odds of current (OR = 0.47; 95% CI = 0.28, 0.79) and daily smoking (OR = 0.40, 95% CI = 0.21, 0.74). More frequent school moves were consistently associated with increased odds of smoking (e.g., OR [currently] = 1.17; 95% CI = 1.07, 1.36). Results indicate that protective factors within the family and school context were consistently associated with smoking measures. Programs and practices that strengthen parent involvement and school support may contribute to prevention efforts.

Trends in Tobacco Product Use Patterns Among U.S. Youth, 1999-2014

Introduction

We examined trends in seven mutually exclusive tobacco product use patterns (T-PUPs) in nationally representative samples of U.S. youth over time and age.

Methods

We used time varying effect modeling on National Youth Tobacco Surveys, 1999-2014 (N = 38662, 9-17 years, M = 15.02). Regression coefficients were estimated as a non-parametric function of time. T-PUPs were cigarette only, non-cigarette combustible only, noncombustible only, non-cigarette combustible and noncombustible dual, cigarette and noncombustible dual, cigarette and non-cigarette combustible dual, and POLY (i.e. cigarettes, non-cigarette combustibles, and noncombustibles) use.

Results

Among youth tobacco users, cigarette only use was the predominant T-PUP from 1999 to 2010. After 2010 and 2013, non-cigarette combustible only (AOR 1.38, CI = 1.02-1.87) and noncombustible only (AOR 1.57, CI = 1.00-2.45) use became more prevalent than cigarette only use. In 2011, dual and POLY T-PUPs were on the rise although not significantly different from cigarette only use. Cigarette only use was the predominant T-PUP among 11- to 17-year-old tobacco users. Non-cigarette combustible only (AOR 0.14, CI = 0.10-0.19), noncombustible only (AOR 0.01, CI = 0.008-0.02), non-cigarette combustible and noncombustible (AOR 0.01, CI = 0.01-0.03), cigarette and noncombustible (AOR 0.02, CI = 0.01-0.04), cigarette and non-cigarette combustible (AOR 0.32, CI = 0.24-0.43), and POLY (AOR 0.02, CI = 0.01-0.04) use were less prevalent than cigarette only use at age 17.

Conclusions

Non-cigarette, dual, and POLY T-PUPs are rising among youth tobacco users. Screening for all tobacco use and delivering treatment during pediatrician visits should be standard clinical practice.

Implications

Tracking trends in tobacco product use patterns (T-PUPs) over time and age is necessary to achieve Healthy People 2020 goal of reducing tobacco use among youth. Trends over time show a rise of non-cigarette T-PUPs especially noncombustible products but cigarette only use remains the most prevalent among 11- to 17-year-old tobacco users. The recent extension of FDA's regulatory jurisdiction over all tobacco products (e.g. e-cigarettes, hookah) is a step toward comprehensive tobacco control especially among youth. Public health practitioners should extend prevention and cessation efforts among youth to T-PUPs beyond exclusive cigarette smoking.

Systematic review of cigars, cigarillos, and little cigars among adolescents: Setting research agenda to inform tobacco control policy

INTRODUCTION

We conducted a systematic review of the literature on cigar research on youth to identify potential future research agenda to generate evidence to inform cigar regulations to prevent cigar use among youth.

METHODS

We searched articles on Medline, EMBASE, and PsycINFO in April 2017 to identify articles relevant to cigars and adolescents. Two independent coders examined 48 articles to determine eligibility: (1) published between 2000-April 2017; (2) published in English; (3) conducted in the United States; (4) published in a peer-review journal; (5) examined cigars, cigarillos, or little cigars; (6) included youth (12-18 years old); and (7) included empirical data. Three independent coders reviewed the included articles (n = 48) to identify whether the studies addressed FDA's Research Priorities.

RESULTS

The studies addressed FDA's Research Priorities of "behavior" (n = 48), "communications" (n = 4), "marketing influences" (n = 1), and "impact analysis" (n = 1). Studies on "behavior" underscored the need for improvements in measurement, such as using brand names and distinguishing cigar products. The review revealed the need for restrictions on cigar flavors, development of media campaigns and interventions, increasing the cost (via taxation), and evaluating the impact of cigar policies.

CONCLUSIONS

The studies mostly focused on surveillance of behaviors and use patterns, which revealed cigar specific issues to address in policies to decrease cigar use among youth. The lack of studies addressing other FDA's research priorities highlighted the critical need for future studies that inform prevention of youth cigar use.

Evolution of attitudes, trends and perceptions of smoking among middle and secondary school students in the Gharb Region, Morocco, 2010-2015

Background

Tobacco use is an important public health issue. Morocco implemented a tobacco control programme, which has been ongoing among students at middle and secondary schools since 2010.

Aim

This study aims to compare the trend in smoking among the programme beneficiaries with the results of the initial study conducted prior to the implementation of the programme.

Setting

This study was conducted in middle and secondary schools of the Gharb Region in Morocco between 2010 and 2015.

Methods

Two cross-sectional studies were conducted in 2010 and 2015 in the middle and secondary schools of the Gharb Region. Multistage cluster sampling was used. The information was collected using a self-administered questionnaire.

Results

In the first study in 2010, 5312 students participated, and in the second one in 2015, 4208 students participated. The level of information on smoking and its effects was higher in 2015 (94.0%) than in 2010 (92.5%). In 2010, parents, primary schools and television and radio were more involved in student information on smoking compared to 2015. The proportion of students claiming that tobacco was not a pleasure (86.3%) and that it does not calm nerves (76.5%) was significantly higher in 2015 than in 2010. The prevalence of smoking increased significantly in 2015 (2.9%) against 2010 (1.8%).

Conclusion

This study reports the general positive evolution in knowledge about smoking and its effects. Despite that the prevalence of smokers increased in 2015. The results suggest the need to address family influences on adolescent smoking and to investigate participation of schools in education and training students in tobacco dependence prevention.

Ecological momentary assessment of various tobacco product use among young adults

INTRODUCTION

Young adults are at high risk for using traditional and novel tobacco products. However, little is known about daily/weekly use patterns or psychosocial triggers for using various tobacco products.

METHODS

This ecological momentary assessment (EMA) study examined timing, tobacco cravings, affect, social context, and other substance use (alcohol, marijuana) in relation to use of cigarettes, electronic nicotine delivery systems (ENDS), and any tobacco product (i.e., cigarettes, ENDS, cigars, hookah), respectively. We also examined interactions between these predictors, sex, and race/ethnicity. From a longitudinal study of 3418 18-25 year-olds from seven Georgia colleges/universities, we recruited 72 reporting current tobacco use to participate in the 21-day EMA study; 43 participated, of which 31 completed ≥66% assessments and were analyzed. Cravings, affect, social context, and substance use were assessed daily across four four-hour windows.

RESULTS

Of the 31 participants, average age was 21.10 years (SD = 1.95), 45.2% were female, and 71.0% non-Hispanic White; 71.0% used cigarettes, 58.1% ENDS, 38.7% cigars, and 25.8% hookah (25.6% used one product, 46.5% two, 27.9% ≥ three). Predictors of cigarette use included higher anxiety, greater odds of marijuana and alcohol use, and higher boredom levels among women. Predictors of ENDS use included being non-White and greater odds of marijuana use, as well as higher tobacco cravings among women and higher boredom among men. Predictors of any tobacco product use included being non-White, higher boredom levels, and greater odds of marijuana and alcohol use.

CONCLUSIONS

Distinct interventions may be needed to address use of differing tobacco products among young adults.

Identifying behavioural characteristics of tobacco product and e-cigarette use clusters: A repeat cross-sectional analysis

BACKGROUND

Youth may use a variety of tobacco products and e-cigarettes. However, there is a lack of evidence for the combinations of tobacco products and e-cigarettes commonly used by youth in Canada and whether youth from different usage classes share similar characteristics.

METHODS

A cohort of 9th grade students from Ontario, Canada was identified at baseline (2013-14) of the COMPASS study (n = 4651). Classes of youth that currently use similar combinations of tobacco products and e-cigarettes were identified at baseline, one (FY1) and two years later (FY2) using latent class analysis. Multinomial logistic regression models identified demographic and behavioural characteristics (e.g., environmental influences, substance use behaviours, etc.) of youth in current tobacco and e-cigarette use classes relative to youth in non-current use classes.

RESULTS

At baseline, a three-class model was identified as best, while a four-class model was identified at FY1 and FY2. A non-current use group and an all-product use group were identified every year. Students that reported having friends that smoked cigarettes, binge drinking, and using marijuana were more likely to be classified into a current use class.

CONCLUSIONS

Tobacco cigarettes were more likely to be used with other products than on their own. An all-product use group was identified across all three survey waves and the prevalence of this group increased over time. Given that many youth in this study used more than one tobacco product or e-cigarette and commonly reported binge drinking and using marijuana, prevention and cessation activities should address the use of multiple products.

Electronic cigarettes: a task force report from the European Respiratory Society

There is a marked increase in the development and use of electronic nicotine delivery systems or electronic cigarettes (ECIGs). This statement covers electronic cigarettes (ECIGs), defined as "electrical devices that generate an aerosol from a liquid" and thus excludes devices that contain tobacco. Database searches identified published articles that were used to summarise the current knowledge on the epidemiology of ECIG use; their ingredients and accompanied health effects; second-hand exposure; use of ECIGs for smoking cessation; behavioural aspects of ECIGs and social impact; in vitro and animal studies; and user perspectives.ECIG aerosol contains potentially toxic chemicals. As compared to conventional cigarettes, these are fewer and generally in lower concentrations. Second-hand exposures to ECIG chemicals may represent a potential risk, especially to vulnerable populations. There is not enough scientific evidence to support ECIGs as an aid to smoking cessation due to a lack of controlled trials, including those that compare ECIGs with licenced stop-smoking treatments. So far, there are conflicting data that use of ECIGs results in a renormalisation of smoking behaviour or for the gateway hypothesis. Experiments in cell cultures and animal studies show that ECIGs can have multiple negative effects. The long-term effects of ECIG use are unknown, and there is therefore no evidence that ECIGs are safer than tobacco in the long term. Based on current knowledge, negative health effects cannot be ruled out.

Regional and gender differences in tobacco use among American Indian youth

Tobacco use is among the top preventable causes of death in the United States, and American Indian (AI) adolescents tend to use tobacco at higher rates compared to the general population. To examine regional and gender differences in rates of smoked, smokeless, and poly-tobacco use among AI adolescents as compared to White counterparts, participants were sampled as part of a larger ongoing study examining substance use among American Indian adolescents who completed the American Drug and Alcohol Survey. A multilevel analytic approach was used to examine the effects of demographic variables on tobacco use. AI disparities were present for past month and lifetime rates of smoked and smokeless tobacco use, and these disparities varied by region and gender. AI disparities in smoked tobacco use were largest in the Upper Great Lakes region, with odds of current and ever smoking among AIs 3.34 to 4.15 times that of Whites, respectively, p < .001. Regional differences in AI disparities were not significant for lifetime smokeless or poly-tobacco use, p ≥ .675. With regard to gender differences, AI disparities in reports of ever smoking were largest among females, OR = 2.61, p < .001. Similar to cigarette smoking, AI disparities in reports of ever using smoked, smokeless, or poly-tobacco were largest among females, OR = 2.51 and 2.56, respectively, p < .001. Our results suggest a need for prevention and intervention programs to be implemented with consideration for adolescents' demographic characteristics, including geographic region, gender, and AI status.

Latent Class Analysis to Examine Patterns of Smoking and Other Tobacco Products in Young Adult Bar Patrons

PURPOSE

Use of multiple tobacco products is increasing, particularly among young adults. Latent class analysis of substance-use patterns provides a framework for understanding the heterogeneity of use. We sought to identify different patterns of cigarette, e-cigarette, hookah, cigarillo, and smokeless tobacco use among young adult bar patrons.

METHODS

We conducted repeated cross-sectional surveys of randomized time location samples of young adult California bar patrons in 2013 and 2014. Latent class analysis was used to examine patterns of use among current (past 30-day) tobacco users. Classes were compared on demographic characteristics and tobacco use correlates.

RESULTS

Overall 84.4% of the current tobacco users were cigarette smokers, 38.7% used electronic cigarettes, 35.9% used hookah, 30.1% smoked cigars/cigarillos, and 15.4% used smokeless tobacco in the past 30 days. We extracted six latent classes: "Cigarette only" (n = 1690), "Hookah mostly" (n = 479), "High overall use" (n = 528), "Smokeless mostly" (n = 95), "E-cigarette mostly" (n = 439), "Cigars mostly" (n = 435). These classes differed in their risk profiles on both current use compared to no use, and number of days they used each tobacco product. Differences between classes emerged on demographics (age, sex, race/ethnicity) and tobacco correlates including perceived peer smoking, antitobacco industry attitudes, prioritizing social activities, and advertising receptivity.

CONCLUSIONS

Understanding different patterns of multiple tobacco product use may inform both prevention and cessation programming for young adults. It may be efficient to tailor messages to different latent classes and address the distinct demographic and attitudinal profiles of groups of multiple tobacco product users.

Tobacco Product Harm Perceptions and New Use

: media-1vid110.1542/5839992833001PEDS-VA_2018-1505Video Abstract BACKGROUND: Researchers in several studies have examined correlations between tobacco harm perceptions and tobacco use in youth, but none have prospectively addressed the association between harm perceptions and subsequent new use across multiple noncigarette products.

METHODS

Product-specific absolute and relative harm perceptions for cigarettes, electronic cigarettes (e-cigarettes), cigars, pipes, hookah, and smokeless tobacco were collected at wave 1 (W1) (2013-2014) among youth in the nationally representative US Population Assessment of Tobacco and Health Study (12-17 years of age; n = 10 081). At wave 2 (W2) (2014-2015), product-specific new use was calculated. Adjusted relative risks were used to estimate if harm perceptions at W1 predicted W2 new tobacco use.

RESULTS

The proportion of youth who endorsed "a lot of harm" was highest for cigarettes (84.8%) and lowest for e-cigarettes (26.6%); the proportion of youth who thought products were "more harmful" than cigarettes was highest for cigars (30.6%) and lowest for e-cigarettes (5.1%). Among youth who had not used those products at W1, product-specific new use at W2 ranged from 9.1% (e-cigarettes) to 0.6% (pipes). Youth who believed that noncombustible tobacco products posed "no or little harm" at W1 were more likely to have tried those products at W2 (P < .05). Youth who viewed e-cigarettes, hookah, and smokeless tobacco as "less harmful" than cigarettes at W1 were more likely to try those tobacco products at W2 (P < .05).

CONCLUSIONS

Low harm perceptions of noncigarette tobacco products predict new use of these products by youth within the next year. Targeting product-specific harm perceptions may prevent new tobacco use among youth.

Poly-product drug use disparities in adolescents of lower socioeconomic status: Emerging trends in nicotine products, marijuana products, and prescription drugs

Greater diversification of nicotine products, marijuana products, and prescription drugs have contributed to increasing trends in adolescent poly-product use-concurrent use of 2 or more drugs-within these drug classes (e.g., nicotine use via e-cigarettes, hookah, cigars). Extant work suggests that poly-product drug use disparities may be disproportionately heightened among youth from lower socioeconomic status (SES) backgrounds, however, it is unknown whether indicators of objective SES or subjective SES differentially increase risk of poly-product use including these newly emerging drugs. This study examined associations of parental education and subjective social status (SSS: perceptions of social standing compared to society [societal SSS] or school [school SSS]) with poly-product use of nicotine products, marijuana products, and prescription drugs among adolescents (N = 2218). Lower parental education and school SSS were associated with increased odds of past or current single, dual, or multiple product use of nicotine, marijuana, and prescription drugs. Findings suggest that risk for poly-product use of emerging drugs are higher for adolescents who endorse lower perceived social standing relative to peers at school and who were from a lower parental SES background.

Smoking and Lung Cancer Mortality in the United States From 2015 to 2065: A Comparative Modeling Approach

BACKGROUND

Tobacco control efforts implemented in the United States since the 1960s have led to considerable reductions in smoking and smoking-related diseases, including lung cancer.

OBJECTIVE

To project reductions in tobacco use and lung cancer mortality from 2015 to 2065 due to existing tobacco control efforts.

DESIGN

Comparative modeling approach using 4 simulation models of the natural history of lung cancer that explicitly relate temporal smoking patterns to lung cancer rates.

SETTING

U.S. population, 1964 to 2065.

PARTICIPANTS

Adults aged 30 to 84 years.

MEASUREMENTS

Models were developed using U.S. data on smoking (1964 to 2015) and lung cancer mortality (1969 to 2010). Each model projected lung cancer mortality by smoking status under the assumption that current decreases in smoking would continue into the future (status quo trends). Sensitivity analyses examined optimistic and pessimistic scenarios.

RESULTS

Under the assumption of continued decreases in smoking, age-adjusted lung cancer mortality was projected to decrease by 79% between 2015 and 2065. Concomitantly, and despite the expected growth, aging, and longer life expectancy of the U.S. population, the annual number of lung cancer deaths was projected to decrease from 135 000 to 50 000 (63% reduction). However, 4.4 million deaths from lung cancer are still projected to occur in the United States from 2015 to 2065, with about 20 million adults aged 30 to 84 years continuing to smoke in 2065.

LIMITATION

Projections assumed no changes to tobacco control efforts in the future and did not explicitly consider the potential effect of lung cancer screening.

CONCLUSION

Tobacco control efforts implemented since the 1960s will continue to reduce lung cancer rates well into the next half-century. Additional prevention and cessation efforts will be required to sustain and expand these gains to further reduce the lung cancer burden in the United States.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Heated tobacco products likely appeal to adolescents and young adults

BACKGROUND

Beginning in the 1960s in the USA and globally since 1998, tobacco companies have beenaggressively promoting heated tobacco products (HTP). In 2016, Philip Morris International (PMI) applied to the US Food and Drug Administration (FDA) seeking authorisation to market their IQOS HTP system and flavoured 'HeatSticks' in the USA as a modified-risk tobacco product (MRTP).

METHODS

We systematically evaluated the publicly available data PMI submitted to FDA in its MRTP application to determine whether PMI's IQOS product meets the US Tobacco Control Act's standard for MRTP claims. We examined whether PMI provided sufficient data showing tobacco users will not initiate with IQOS, that youth will not misperceive the MRTP-related claims being made concerning IQOS, and how youth perceive health risks associated with IQOS.

RESULTS

PMI's own studies failed to provide evidence that youth, including non-users and former users, will not find IQOS appealing, will not initiate use of IQOS and will not perceive these products as risk-free. Further, PMI did not refer to independent studies conducted among adolescents which could influence their conclusions. Finally, their studies suffered from design and implementation flaws and cannot be relied on to support the proffered claims.

CONCLUSION

PMI's own data and available evidence from scientific studies conducted independent of the tobacco industry regarding how novel tobacco products are currently being marketed suggest that introduction of IQOS will result in adolescent and young adult non-users initiating tobacco use with IQOS and could also increase poly-use of IQOS along with other tobacco products.

Adolescents' Aided Recall of Targeted and Non-Targeted Tobacco Communication Campaigns in the United States

We examined whether advertisements from two national tobacco control campaigns targeting adolescents (i.e., The Real Cost, Fresh Empire) and one campaign targeting adults (i.e., Tips from Former Smokers) were reaching adolescents. Data came from a national sample of adolescents aged 13 to 17 years (n = 975) surveyed by phone from August 2016 to May 2017. We assessed recall and attitudes toward five specific advertisements and three campaign slogans and examined differences by sub-groups. Almost all (95%) adolescents recalled seeing at least one campaign advertisement. Aided recall of The Real Cost and Tips from Former Smokers slogans was high (65.5% and 71.6%, respectively), while aided recall of Fresh Empire slogan was lower (15.3%) (χ² p-value: p < 0.001); however, Black adolescents had higher odds of recalling the Fresh Empire ad (aOR: 2.28, 95% CI: 1.39, 3.73) and slogan (aOR: 2.64, 95% CI: 1.06, 6.54) compared to White adolescents. Increased exposure to the advertisements (i.e., recalling more advertisements) was significantly associated with higher odds of reporting negative feelings toward tobacco products in 4/5 models (aORs from 1.34 to 1.61). Large-scale national campaigns can have wide reach among both targeted and non-targeted audiences with added benefits for cumulative cross-campaign exposure to advertisements.

Impulsivity and tobacco product use over time

Impulsivity has been consistently associated with greater likelihood and intensity of cigarette smoking, but most studies have been cross-sectional. Additionally, while some initial studies are suggestive, less is known about links between impulsivity and use of e-cigarettes or hookah tobacco. The goal of the present study was to test the hypothesis that the urgency and sensation seeking aspects of impulsivity would be prospectively associated with patterns of cigarette, e-cigarette, and hookah tobacco use over time. Young adults (n = 335; 56% male) aged 18-24 who were non- and never-daily cigarette smokers at baseline completed 9 online assessments of tobacco product use over two years. Longitudinal negative binomial regression models were used to evaluate relationships between impulsivity components and product use. Frequency of use of all three products declined over time. Higher levels of positive urgency (cigarette), negative urgency (hookah), and lack of premeditation (e-cigarette, hookah) were associated with smaller reductions in frequency of specific products. Additionally, higher negative urgency predicted greater quantity of cigarettes consumed, and higher sensation seeking was associated with more frequent e-cigarette use. Findings suggest impulsivity components differentially predict tobacco use over time, indicating that motives and/or risk factors for tobacco use may be product-specific.

Tobacco product initiation is correlated with cross-product changes in tobacco harm perception and susceptibility: Longitudinal analysis of the Population Assessment of Tobacco and Health youth cohort

Youth initiation with one tobacco product is associated with risk of using additional tobacco types. How use of one product potentially encourages use of others could result from changing tobacco-related perceptions. This study aimed to evaluate how tobacco product initiation correlates with changes in susceptibility (curiosity and willingness) and perceived harm of other tobacco products. For each of cigarettes, e-cigarettes, hookah, and smokeless tobacco, youth (ages 12-16; N = 8005) rated perceived harm, curiosity, and willingness to try in Waves 1 and 2 of the Population Assessment of Tobacco and Health (United States, 2013-2015). For each product, we estimated associations between decreased harm rating, increased curiosity, or increased willingness with initiation (from never- to ever-use) of cigarettes, e-cigarettes, hookah, smokeless tobacco, or other combustible products using multivariate (multiple outcomes) regression, adjusting for other tobacco risk factors. Tobacco product initiation was associated with decreased perceived harm for that product and with decreased perceived harm, increased curiosity, and increased willingness in some, but not all, cross-product combinations. Most cross-product combinations of initiation and susceptibility yielded positive associations. For example, trying e-cigarettes was associated with concomitant increases in curiosity about cigarettes (OR: 5.69; 95% CI: 3.68, 8.79) and hookah (OR: 4.19; 95% CI: 2.55, 6.88) and with increased willingness to try cigarettes (OR: 9.61; 95% CI: 5.67, 16.3), hookah (OR: 8.46; 95% CI: 4.76, 15.0), and smokeless tobacco (OR: 3.48; 95% CI: 1.75, 6.94). New use of one tobacco product may catalyze subsequent use of others through cross-product changes in perceptions and susceptibility.

Cigarettes, Little Cigars, and Cigarillos: Initiation, Motivation, and Decision-Making

Introduction

Cigarettes and little cigars and cigarillos (LCCs) are the most prevalent dual-use tobacco combination; one-third of cigarette smokers use LCCs. Risk factors for multiple tobacco product use have been reported; however, there is little understanding of why some individuals transition to and maintain multiple product use. In this study, we examine narratives of tobacco product initiation and decision-making among LCC-only and LCC-cigarette smokers.

Methods

We audio-recorded in-depth interviews with 60 individuals, aged 14-28, who reported smoking more than or equal to 1 cigarillo per week; half also smoked cigarettes. Transcribed interviews were coded using a phenomenological approach to examine themes about smoking initiation, motivation, and product decision-making.

Results

Among dual users, 60% began smoking LCCs before or at the same time as cigarettes, and 40% began smoking cigarettes first. Reasons for smoking cigarettes in addition to LCCs included easier access when experiencing craving and less time to smoke the product. Cigarette smokers reported first smoking LCCs in social contexts when sharing LCCs with other smokers, or when they could afford a single LCC but not a pack of cigarettes. LCC-only smokers reported not smoking cigarettes because of their expense, unpleasant taste and/or smell, and fear of becoming addicted.

Conclusions

In this sample of current LCC users, half also used cigarettes. Product initiation order was almost evenly split, but reasons for initiating the second product differed, with immediacy of reducing cravings as a key reason for LCC users to smoke a cigarette and social and financial reasons for cigarette users to smoke an LCC.

Implications

Understanding how and why dual use is initiated and sustained can inform policies to help prevent increased nicotine dependence and initiation of additional tobacco products. This study demonstrates that the beliefs, perceptions, and practices of LCC-only and dual users inform their product selection. Our findings point to the need to apply the strategies that have been effective at decreasing cigarette consumption to LCCs.

Trends and Racial Disparities in Mono, Dual, and Poly Use of Tobacco Products Among Youth

Introduction

We examined racial disparities in mono, dual, and poly use of tobacco products including whether racial disparities changed over time.

Methods

We analyzed data on high school students from the North Carolina Youth Tobacco Survey collected in 2011, 2013, and 2015. Dual and poly use included use of two and three or more tobacco products, respectively, in the past month. Multinomial regression models assessed racial differences and changes over time in mono, dual, and poly use. Data include product combinations most commonly used by youth from different racial groups.

Results

In total, 24% (in 2011) and 26% (in 2013 and 2015) of students used tobacco products. No significant changes over time were observed in mono (12%) or dual use (6%). Poly use was 6%, 8%, and 7% in 2011, 2013, and 2015, respectively. Relative to nonuse of tobacco, White students had a higher relative risk than Blacks for mono use. Whites and Hispanics had a higher relative risk than Blacks for dual and poly use. Observed racial differences in tobacco use did not change over time. Types of tobacco products used varied by year and race. In 2015, e-cigarette was the most commonly used product among mono users from all racial groups.

Conclusions

Substantial racial variation persists over time in mono and multiple tobacco product use among North Carolina youth, including racial variation in the types of tobacco products used. Research and policy efforts should examine and eliminate factors that drive multiple tobacco use and racial disparities in use among youth.

Implications

This study reports on racial disparities in mono and multiple tobacco product use among youth. White and Hispanic youth have higher relative risk for dual and poly use of tobacco products than Black youth. In addition, significant racial variation exists in the types of tobacco products used among youth mono, dual, and poly users, with cigarettes, cigars, smokeless tobacco, and e-cigarettes being the most commonly used products. Patterns of multiple tobacco product use vary by race and may warrant tailored prevention efforts. Strengthening tobacco control regulations for other tobacco products than cigarettes is critical to reduce multiple tobacco product use among youth.

Distinct Motives for Use Among Polytobacco Versus Cigarette Only Users and Among Single Tobacco Product Users

Background

Alternative tobacco product (ATP) use as well as co-use of various tobacco products has increased in recent years, particularly among young adults. However, little is known about the differential role of motives for ATP or polytobacco use.

Methods

We examined (1) motives for tobacco use in relation to polytobacco versus cigarette only use and (2) motives for tobacco use in relation to levels of tobacco use across products. We analyzed data from past 30-day tobacco users at Wave 2 (Spring 2015) of a six-wave longitudinal study of 3418 students aged 18-25 years from seven U.S. colleges/universities. Variables included sociodemographics, tobacco use (cigarettes, little cigars/cigarillos [LCCs], smokeless tobacco [SLT], hookah, and e-cigarettes), and tobacco use motives (social, self-enhancement, boredom relief, and affect regulation).

Results

Multivariate analyses found that boredom relief motives were associated with polytobacco use versus cigarette only use (p = .007). Higher consumption levels demonstrated the following associations: cigarettes-positively with boredom relief (p = .025) and affect regulation motives (p < .001); LCCs-positively with affect regulation motives (p = .035); SLT-negatively with social (p = .003) and positively with self-enhancement (p = .017) and boredom relief motives (p = .007); and hookah-positively with social (p = .002) and boredom relief motives (p = .033) and negatively with self-enhancement (p = .004) and affect regulation motives (p = .001).

Conclusions

Distinct motives for use were associated with polytobacco use among smokers. Moreover, higher levels of use among single product users also demonstrated distinct associations across use motives. These data should inform targeted cessation interventions addressing motives for use in ATP and polytobacco users.

Implications

Interventionists, public health practitioners, and health care providers must address the increasing issue of ATP and polytobacco use and tailor interventions to reduce ATP and polytobacco use in light of the distinct motives for use.

Single, Dual, and Poly Use of Flavored Tobacco Products Among Youths

Introduction

Flavoring has become the leading reason for current tobacco use among adolescents. This study sought to evaluate patterns of flavored tobacco product use and associated risk factors among youths.

Methods

Weighted estimates of single, dual, and poly use of flavored tobacco products were calculated from the 2014 National Youth Tobacco Survey (n = 21,926). Multinomial logistic regression was performed to assess factors associated with flavored product use.

Results

Among current tobacco users (n = 3,805), 70.0% of students were current users of flavored tobacco products: 42.6% used a single flavored product, 16.8% used 2 flavored products (dual users), and 10.6% used more than 2 flavored products (poly users). Flavored product use, especially dual and poly use, was higher among high school students compared with middle school students. Compared with single flavored tobacco product users (36%), dual (57%) and poly users (79%) of flavored tobacco products had higher prevalences of using flavored e-cigarettes (P < .001). Non-Hispanic blacks and those of other races had lower prevalences than non-Hispanic whites of using flavored products but not nonflavored products. Tobacco use by household members, no perception of harm from tobacco products, and more frequent exposure to tobacco advertisement in newspapers/magazines and stores were associated with increased odds of flavored product use.

Conclusion

The concurrent use of flavored tobacco products is prevalent among youths. E-cigarettes were the leading flavored product and often concurrently used with other flavored tobacco products. Comprehensive control and prevention strategies to reduce flavored tobacco use among youths are needed.

Does E-cigarette Use at Baseline Influence Smoking Cessation Rates among 2-Year College Students?

INTRODUCTION

This study evaluates the impact of baseline e-cigarette use on smoking cessation rates in a national sample of two-year college student smokers.

METHODS

Participants were 1400 students from over 60 two-year colleges across 25 states who were current smokers enrolled in a web-assisted tobacco intervention (WATI) trial. Survey data were collected at baseline, 1-, 6-, and 12-months, with primary outcomes evaluated at 6-months.

RESULTS

At 6-months, baseline e-cigarette users were more likely to report cessation of traditional cigarettes compared to non-users (OR 1.39, 95% CI 1.002-1.92). Cessation was also associated with higher baseline confidence in quitting and greater time to first cigarette in the morning. Baseline e-cigarette use was not found to be associated with self-reported cessation of all nicotine/tobacco products (OR 1.09, 95% CI 0.75-1.58) nor biochemically verified cessation of all nicotine/tobacco products (OR 0.83, 95% CI 0.47-1.47). Higher confidence was again associated with both self-reported and biochemically verified cessation of all nicotine/tobacco products. Female gender was associated only with biochemically verified cessation of all nicotine/tobacco products at 6-months.

CONCLUSIONS

Two-year college students represent a priority population for cessation interventions. The findings from this study highlight the complexities of evaluating the impact of e-cigarette use on cessation.