Thirty-day smoking in adolescence is a strong predictor of smoking in young adulthood

Associations of weight control related behaviors with current cigarette smoking among Chinese adolescents: Results from an ongoing school-based survey in Zhejiang province

INTRODUCTION

Previous studies have suggested that adolescents may smoke cigarettes to control weight, but relevant research is scarce in Chinese youth. This study was conducted to examine the associations of weight control related behaviors with cigarette smoking in Chinese students.

METHODS

This was a secondary analysis of data for 24835 middle and high school students drawn from the 2022 Zhejiang Youth Risk Behavior Survey of China which collected self-reported information of cigarette smoking, weight control strategies and other health-related behaviors. Multivariable logistic regression models were used to estimate the adjusted odds ratios (AORs) with 95% confidence intervals (CIs) for the study associations.

RESULTS

Overall, there were 998 (4.02%) current cigarette smokers in this wave of the Zhejiang YRBS (2022). Neither trying to control weight nor healthy weight control behavior of exercising was associated with current cigarette smoking (AOR=1.15; 95% CI: 0.97-1.37 and AOR=1.01; 95% CI: 0.85-1.20, respectively). Meanwhile, unhealthy weight control behaviors of taking laxatives (AOR=1.52; 95% CI: 1.03-2.26), taking diet pills (AOR=1.82; 95% CI: 1.26-2.62), dieting (AOR=1.24; 95% CI: 1.04-1.49), and fasting (AOR=1.81; 95% CI: 1.40-2.34) were significantly associated with increased odds of current cigarette smoking.

CONCLUSIONS

Screening and developing interventions for unhealthy weight control behaviors should be considered as part of smoking prevention programs among adolescents.

[Use of tobacco cigarettes, e-cigarettes, and shishas among children and adolescents: Results of the "Präventionsradar" from 2016 to 2023]

AIM

To measure trends in the use of various smoking products among children and adolescents from 2016 to 2023.

METHOD

The data is based on seven waves of the "Präventionsradar", a school-based epidemiological study in grades 5 to 10. The primary endpoints of the study were the lifetime and monthly prevalence of the use of tobacco cigarettes, e-cigarettes, shisha and the use of at least two of these smoking products (combined use). Prevalence estimates are based on logistic regression models.

RESULTS

The analysis was based on 94,127 questionnaires. The sex ratio was balanced (49% female), mean age was 13 years (SD=1.8). In 2022/2023, the lifetime prevalence of smoking tobacco cigarettes was 18.8% (95% CI 18.1-19.5), of e-cigarettes 23.5% (95% CI 22.8-24.3), of shisha 14.0% (95% CI 13.4-14.7) and combined use 19.0% (95% CI 18.3-19.7). The monthly prevalence of smoking tobacco cigarettes was 5.9% (95% CI 5.5-6.4), of e-cigarettes 7.0% (95% CI 6.5-7.4), of shisha 3.2% (95% CI 2.8-3.5) and combined use 4.8% (95% CI 4.4-5.2). The following trends in lifetime prevalence have emerged since 2016: tobacco cigarettes (-3.0 percentage points), e-cigarettes (+1.8 percentage points), shisha (-9.2 percentage points), combined use (-2.7 percentage points). In the years of the COVID-19 pandemic, youth smoking decreased and rose again post-COVID with the exception of shisha.

DISCUSSION

The use of smoking products in adolescence occurs frequently. Over the observational period, a trend reversal towards e-cigarettes as the most popular product among children and young people is most likely. In addition, the combined use of several smoking products has become a common pattern of consumption. Consistent preventive measures are required in order to achieve the goal of a smoke-free society in 2040.

Vuse Solo e-cigarettes do not provide net benefits to public health: a scientific analysis of FDA's marketing authorisation

In October 2021, the US Food and Drug Administration (FDA) authorised marketing of RJ Reynolds Vapor Company's (RJR) Vuse Solo e-cigarette through FDA's Premarket Tobacco Product Application (PMTA) pathway. FDA concluded that RJR demonstrated Vuse products met the statutory standard of providing a net benefit to public health. A review of FDA's scientific justification reveals deficiencies: (1) not adequately considering Vuse's popularity with youth and evidence that e-cigarettes expanded the nicotine market and stimulate cigarette smoking; (2) trading youth addiction for unproven adult benefit without quantifying these risks and benefits; (3) not considering design factors that appeal to youth; (4) not addressing evidence that e-cigarettes used as consumer products do not help smokers quit and promote relapse in former smokers; (5) not discussing evidence that dual use is more dangerous than smoking; (6) narrowly focusing on the fact that e-cigarettes deliver lower levels of some toxicants without addressing direct evidence on adverse health effects; (7) downplaying significant evidence of other substantial harms; (8) not acting on FDA's own study showing no all-cause mortality benefit of reducing (but not stopping) cigarette use; and (9) improperly considering e-cigarettes' high abuse liability and potential for high youth addiction and undermining tobacco cessation. Because marketing these products is not appropriate for the protection of the public health, FDA should reconsider its Vuse marketing order as statutorily required and not use it as a template for other e-cigarette PMTAs. Policymakers outside the USA should anticipate that tobacco companies will use FDA's decision to try to weaken tobacco control regulation of e-cigarettes and promote their products.

Trends in vaping and smoking behavior before and during the COVID-19 pandemic in Canada: Beneficial and potentially detrimental changes

INTRODUCTION

E-cigarette and cigarette use may have changed during the COVID-19 pandemic, however, there is no consensus in existing literature, and current Canadian studies have not used representative samples. Thus, there is a need for robust national estimates.

OBJECTIVE AND METHODS

The primary objective was to describe the 30-day period prevalence of smoking and vaping before and during the COVID-19 pandemic in Canada. This study analyzed three years of the cross-sectional Canadian Tobacco and Nicotine Survey: 2019 (pre-pandemic), 2020 (9 months into the pandemic) and 2021 (21 months into pandemic).

RESULTS

Thirty-day period prevalence of vaping over the 2019, 2020, and 2021 study periods were 4.8 (95%CI: 4.2-5.3), 4.6% (95%CI: 4.1-5.2), and 5.2% (95%CI: 4.7-5.7), respectively. The 30-day period prevalence of smoking over the 2019, 2020, and 2021 study periods were 11.9% (95%CI: 10.9-12.7), 10.3% (95%CI: 9.4-11.2), and 10.3% (95%CI: 9.4-11.1), respectively. Notably, estimates of smoking for females decreased considerably from 2019 (11.0%; 95%CI: 9.9--12.2%) to 2020 (8.6%; 95%CI: 7.5-9.7). Estimates of vaping in those aged 20-24 increased substantially from 2020 (13.0%; 95%CI: 10.9-15.1) to 2021 (17.2%; 95%CI: 15.4-18.9).

CONCLUSIONS

Changes to smoking and vaping were restricted to subsets within the population. In those aged 20-24, there was a modest increase in vaping from 2020 to 2021. In females, there was a decrease in smoking from 2019 to 2020, which persisted in 2021.

[Use of tobacco cigarettes, e-cigarettes, and shishas among children and adolescents: Results of the 'Präventionsradar' from 2016 to 2023]

AIM

To measure trends in the use of various smoking products among children and adolescents from 2016 to 2023.

METHOD

The data is based on seven waves of the "Präventionsradar", a school-based epidemiological study in grades 5 to 10. The primary endpoints of the study were the lifetime and monthly prevalence of the use of tobacco cigarettes, e-cigarettes, shisha and the use of at least two of these smoking products (combined use). Prevalence estimates are based on logistic regression models.

RESULTS

The analysis was based on 94,127 questionnaires. The sex ratio was balanced (49% female), mean age was 13 years (SD=1.8). In 2022/2023, the lifetime prevalence of smoking tobacco cigarettes was 18.8% (95% CI 18.1-19.5), of e-cigarettes 23.5% (95% CI 22.8-24.3), of shisha 14.0% (95% CI 13.4-14.7) and combined use 19.0% (95% CI 18.3-19.7). The monthly prevalence of smoking tobacco cigarettes was 5.9% (95% CI 5.5-6.4), of e-cigarettes 7.0% (95% CI 6.5-7.4), of shisha 3.2% (95% CI 2.8-3.5) and combined use 4.8% (95% CI 4.4-5.2). The following trends in lifetime prevalence have emerged since 2016: tobacco cigarettes (-3.0 percentage points), e-cigarettes (+1.8 percentage points), shisha (-9.2 percentage points), combined use (-2.7 percentage points). In the years of the COVID-19 pandemic, youth smoking decreased and rose again post-COVID with the exception of shisha.

DISCUSSION

The use of smoking products in adolescence occurs frequently. Over the observational period, a trend reversal towards e-cigarettes as the most popular product among children and young people is most likely. In addition, the combined use of several smoking products has become a common pattern of consumption. Consistent preventive measures are required in order to achieve the goal of a smoke-free society in 2040.

Increase of Prevalence of Obesity and Metabolic Syndrome in Children and Adolescents in Korea during the COVID-19 Pandemic: A Cross-Sectional Study Using the KNHANES

(1) Background: The aim of this study was to evaluate the prevalence of obesity and metabolic syndrome since the COVID-19 pandemic outbreak utilizing representative data on youth aged 2-18 years from the Korean National Health and Nutrition Examination Surveys (KNHANES) conducted in 2019-2020. (2) Methods: The survey consists of three parts: health interviews, health examinations, and nutrition surveys. From the 2019 and 2020 surveys, 1371 (2-9 years = 702 and 10-18 years = 669) and 1124 (2-9 years = 543 and 10-18 years = 581) individuals were included in the analysis. (3) Results: The mean body mass index (BMI) increased significantly among youth aged 2-9 years from 16.53 kg/m² in 2019 to 17.1 kg/m² in 2020 (p < 0.01). In youth aged 10-18 years, the BMI was found to increase slightly from 21.25 kg/m² in 2019 to 21.41 kg/m² in 2020 (p = 0.64). The increasing prevalence of extreme obesity was significant in girls, especially those aged 2-9 years (p < 0.01). However, extreme obesity had increased in 10-18-year-old boys (p = 0.08). The overall prevalence of metabolic syndrome in adolescents increased from 3.79% to 7.79% during the COVID-19 pandemic (p = 0.01). (4) Conclusions: We observed that the prevalence of obesity and metabolic syndrome among children and adolescents has increased after the COVID-19 outbreak. This is believed to be associated with an increase in the rate of early comorbidities in adulthood. The prevention of the progression of pediatric obesity has recently become an urgent public health concern in Korea.

Asian American adolescent e-cigarette use and associated protective factors: Heterogeneity in a statewide sample

OBJECTIVES

This study characterized variation in e-cigarette use patterns and related protective factors by ethnicity among Asian American adolescents.

METHODS

Multivariable logistic regressions modelled associations between ethnic group, 6 protective factors (college aspirations, internal developmental assets, positive teacher engagement, family caring, and peer and parent anti-smoking norms), and past 30-day e-cigarette use, adjusting for covariates among 10,482 8th, 9th, and 11th grade Asian American respondents to the 2019 Minnesota Student Survey. Interaction terms (protective factor × ethnic group) were used in 6 subsequent regression models to examine whether the association between each protective factor and e-cigarette use differed as a function of ethnic group.

RESULTS

Respondents included 9.0% Indian, 0.3% Burmese, 7.9% Chinese, 2.5% Filipino, 25.0% Hmong, 3.2% Karen, 4.6% Korean, 2.7% Laotian, 8.2% Vietnamese, 7.5% other, 7.5% multi-ethnic, and 21.6% multi-racial adolescents. E-cigarettes were the predominant form of tobacco use. Laotian and multi-racial groups reported the highest e-cigarette use (16.6% and 16.3%), whereas Chinese and Asian Indians reported the lowest (4.7% and 5.0%). Strong peer anti-smoking norms, higher internal developmental assets scores, and positive teacher engagement were associated with lower odds of e-cigarette use across groups, with significant interactions for internal developmental assets by ethnicity.

CONCLUSIONS

E-cigarettes are the most prevalent tobacco product used by Asian adolescents in Minnesota, with notable heterogeneity by ethnicity. While most established protective factors appeared to function similarly for Asian adolescents, others differed, underscoring the importance of disaggregating data by ethnicity to inform the tailoring of prevention and control strategies for these ethnic groups.

Weight misperception and substance use: Brazilian Study of Cardiovascular Risks in Adolescents (ERICA)

BACKGROUND

Adolescence is a crucial period for body image formation. Weight misperception is the discrepancy between individuals' body weight perception and their actual nutritional status. Both weight concerns and substance use are common among adolescents, and there is evidence of an associations between these two variables. Thus, the aim of this study was to assess the association between weight misperception and substance use (smoking and alcohol) in a national sample of normal weight Brazilian adolescents.

METHODS

Data were obtained from the Brazilian Study of Cardiovascular Risks in Adolescents (ERICA), a cross-sectional, multicenter, national, school-based survey, carried out in 124 municipalities with more than 100,000 inhabitants from Brazil. The sample included adolescents aged 12-17 years, classified as normal weight by nutritional status evaluation. The following measures were collected: weight underestimation and overestimation (exposure); having tried cigarette smoking, current smoking, current alcohol consumption, binge drinking and current smoking and alcohol consumption(outcomes); macro-region, sex, type of school, and excessive screen time (confounders). The frequency of variables was calculated with 95% confidence intervals (CI). Poisson regression models were used to estimate prevalence ratios (PR).

RESULTS

In total, data from 53,447 adolescents were analyzed. Weight misperception was present in a third of the adolescents, with similar prevalence of weight underestimation and overestimation. In adolescents aged 12-14 years, weight underestimation and overestimation were associated with having tried cigarette smoking (PR: 1.18 and 1.43, respectively), current alcohol consumption (PR: 1.33 for both weight misperception categories), and binge drinking (PR: 1.96 and 2.01, respectively). Weight underestimation was associated with both having tried cigarette smoking and current alcohol consumption in boys (PR: 1.14 and 1.16, respectively) and girls (PR: 1.32 and 1.15, respectively). In girls, weight overestimation was associated with all substance use variables (PR between 1.19 and 1.41).

CONCLUSIONS

Our results showed an association between weight misperception and having tried cigarette smoking, alcohol consumption, and binge drinking in younger adolescents. In addition, weight overestimation was associated with all substance use indicators in girls. Based on our findings, interventions aimed to improve weight perception in normal weight adolescents may contribute to the reduction of substance use in this population.

Gender inequalities in physical activity among adolescents from 64 Global South countries

PURPOSE

The aims of this study were to (a) describe gender inequalities in physical activity (PA) among adolescents from Global South countries, and (b) investigate the relationship between gender inequalities in PA and contextual factors, such as geographic region, human development index, gender inequality index, and unemployment rates.

METHODS

We analyzed cross-sectional data from the Global School-Based Student Health Survey conducted in Global South countries between 2010 and 2020 among 13- to 17-year-old adolescents. Country-context variables were retrieved from secondary data sources (World Health Organization, World Bank, and Human Development Reports). PA was assessed by a self-administered questionnaire querying the number of days in the past week in which participants were physically active for a total of at least 60 min. PA absolute gender inequalities were evaluated by the differences in the prevalence between boys and girls, 95% confidence intervals (95%CIs) were estimated using the bootstrap method. Relative inequalities were obtained through Poisson regression. Meta-analyses with random effects were used to calculate pooled estimates of absolute and relative inequalities.

RESULTS

Based on 64 Global South countries/surveys, the prevalence of PA was 6.7 percentage points (p.p.) higher in boys than in girls, ranging from 0.5 p.p. in Afghanistan to 15.6 p.p. in Laos (I²= 85.1%). The pooled ratio for all countries showed that boys presented a PA prevalence 1.58 times higher than girls (95%CI: 1.47-1.70) on average. The highest absolute and relative inequalities were observed in high income countries. Countries with higher Human Development Index rankings and lower Gender Inequality Index rankings also presented greater gender differences.

CONCLUSION

Given that girls are overall less active than boys across the globe, the findings of this study reinforce that macro- and micro-level changes should be actively sought if we aim to increase population levels of PA in adolescents and promote equity in PA.

Local Tobacco 21 Policies are Associated With Lower Odds of Tobacco Use Among Adolescents

INTRODUCTION

Tobacco 21 (T21) policies have shown promise in reducing cigarette use among adolescents. This study examined whether local T21 policies affected adolescent use of a variety of tobacco products and whether results differed by grade level.

METHODS

We used repeated cross-sectional data from eighth, ninth, and eleventh-grade respondents to the 2016 (n = 107 981) and 2019 (n = 102 196) Minnesota Student Surveys. Generalized estimating equations modeled eight adolescent tobacco use outcomes in 2019 (past 30-day use of any tobacco, cigarettes, cigars, e-cigarettes, hookah, chewing tobacco, flavored tobacco, and multiple products) by T21 exposure, defined as respondents' attendance at a school within a jurisdiction with T21 policy implementation between the two surveys. Models controlled for demographic characteristics and product-specific baseline tobacco use at the school level in 2016 and were stratified by grade.

RESULTS

After adjusting for baseline tobacco use and other demographics, T21-exposed eighth and ninth-grade students had significantly lower odds of tobacco use than unexposed peers in five of eight models, i.e. any tobacco (aOR = 0.80, 95% CI: 0.74, 0.87), cigarettes (aOR = 0.81, 95% CI: 0.67, 0.99), e-cigarettes (aOR = 0.78, 95% CI: 0.71, 0.85), flavored tobacco (aOR = 0.79, CI: 0.70, 0.89), and dual/poly tobacco (aOR = 0.77, 95% CI: 0.65, 0.92). T21-exposed eleventh-grade students did not differ significantly in their odds of any tobacco use outcomes relative to their unexposed peers.

CONCLUSIONS

T21 exposure is associated with lower odds of multiple forms of tobacco use, particularly among younger adolescent populations, supporting the implementation of T21 policies to reduce tobacco use in this population.

Clustering of South Korean Adolescents' Health-Related Behaviors by Gender: Using a Latent Class Analysis

Background: Health-related behaviors during adolescence could influence adolescents’ health outcomes, leading to either advantageous or deteriorative conditions. Clustering of adolescents’ health-related behaviors by gender identifies the target groups for intervention and informs the strategies to be implemented for behavioral changes. Methods: Data from 1807 adolescents in grades 7 and 10 in a city in South Korea were used. Health-related behaviors including eating habits, physical activity, hand washing, brushing teeth, drinking alcohol, smoking, and Internet use were examined. Latent class analysis (LCA) was used to identify subgroups of adolescents with regard to their health-related behaviors. Results: A four-class model was the most adequate grouping classification across genders: adolescents with (1) healthy behaviors, (2) neither health-promoting nor health-risk behaviors, (3) good hygiene behaviors, and (4) unhealthy behaviors. The majority of both male and female adolescents were classified into the healthy group. Male adolescents belonging to the healthy group were more likely to engage in vigorous physical activities, while vigorous physical activity was not important for female adolescents. The smallest group was the unhealthy group, regardless of gender; however, the proportion of boys in the unhealthy group was almost twice that of girls. Only female adolescents engaged in excessive Internet use, especially the group with neither health-promoting nor health-risk behaviors. Conclusion: To improve adolescents’ health-related behaviors, it would be more effective to develop tailored interventions considering the behavioral profiles of the target groups.

Associations between smoking trajectories, smoke-free laws and cigarette taxes in a longitudinal sample of youth and young adults

Cigarette smoking patterns vary within the population, with some individuals remaining never smokers, some remaining occasional users, and others progressing to daily use or quitting. There is little research on how population-level tobacco control policy interventions affect individuals within different smoking trajectories. We identified associations between tobacco control policy interventions and changes across different smoking trajectories among adolescents and young adults. Using 15 annual waves of data drawn from the National Longitudinal Survey of Youth 1997 (NLSY97), we applied a group-based trajectory model to identify associations between days smoked per month, comprehensive smoke-free laws, cigarette tax rates, and known socio-demographic risk factors for membership in different smoking trajectories. Comprehensive smoke-free laws were associated with reduced risk of initiation and reductions in days smoked per month for all trajectories other than occasional users. Higher tax rates were associated with reduced risk of initiation and days smoked for all trajectories other than established users. Overall, population-based tobacco control policies, particularly comprehensive smoke-free laws, were associated with reduced smoking. Tobacco taxes primarily reduced risk of initiation and use among never smokers, experimenters, and quitters, consistent with previous research suggesting that tobacco manufacturers lower prices after tax increases to reduce the cost of continued smoking for established users. These results provide support for expanding smoke-free laws and establishing a minimum tobacco floor price, which could improve public health by reducing the risk of initiation as well as use among occasional and established smokers.

Toward a More Comprehensive Index of Youth Cigarette Smoking: Average Number of Cigarettes Smoked per Day among Students in the United States over Two Decades

Reliance on 30-day prevalence as the principal means of assessing trends in youth cigarette smoking may understate the magnitude of the decrease in youth smoking, because prevalence does not account for smoking frequency or intensity. We analyzed Youth Risk Behavior Survey (YRBS) data from 1997 through 2017 and estimated cigarette smoking prevalence (any smoking in the previous 30 days), frequency (number of smoking days in the previous 30 days), and intensity (cigarettes per day on smoking days). We calculated average cigarettes smoked per day (ACSD) as the product of frequency and intensity, divided by 30. We estimated ACSD among all high school students and by smoking frequency group (i.e., 1–5, 6–9, 10–19, 20–29, or 30 of the previous 30 days), sex, grade level, and race/ethnicity. Among US high school students, ACSD declined by 86.7% from 1997 to 2017, while prevalence declined by 75.8%. Within smoking frequency groups, smoking intensity remained similar over the two decades. However, changes in ACSD over time varied by race/ethnicity; ACSD increased among Hispanic and non-Hispanic Black daily smokers while it decreased among daily smokers of other race/ethnicity groups. ACSD declined more substantially than smoking prevalence over two decades but remained virtually unchanged within smoking frequency groups, indicating that changes in frequency, rather than intensity, drove this decline. Prevalence estimates alone understate the degree to which youth in the United States have rejected smoking, and racial/ethnic disparities in smoking intensity are hidden when we limit our lens to prevalence-only measures.

Cigarette Use Before and After the 2009 Flavored Cigarette Ban

PURPOSE

On September 22, 2009, the U.S. Food and Drug Administration's national ban on flavored cigarette products went into effect, barring the sale of flavored cigarettes with the exception of menthol. Flavored cigarettes largely appeal to and were disproportionately used by youth (under age 18 years). However, little research has evaluated the effects of the ban. This study examined past 30-day cigarette use among youth (12-17 years), young adults (18-25 years), adults (26-49 years), and older adults (≥50 years) before and after the implementation of this ban.

METHODS

Analyses were conducted using 2002-2017 National Survey on Drug Use and Health (NSDUH) data (n = 893,226). Regression models-weighted for national representation-were used to examine past 30-day cigarette use before and after the flavored cigarette ban in different age groups, using a quasi-experimental design incorporating elements of interrupted time series and difference-in-differences design. This design was used to examine differences in pre- versus post-ban smoking within age groups and heterogeneous policy effects between age groups, to help adjust for the generally stronger tobacco control environment over time.

RESULTS

The flavor ban was associated with statistically significant immediate increases as well as reductions over time in youth and young adult use of any cigarettes and menthol cigarettes, compared to older adults. In 2017, the predicted probability of youth and young adult cigarette smoking were reduced by 43% and 27%, respectively, compared to the model predicted probability in absence of the ban. No such effect was observed for older adults. The predicted probability of menthol use was reduced by 60% and 55% for youth and young adults, respectively.

CONCLUSIONS

Findings support the effectiveness of flavored cigarette bans at reducing cigarette use among young people and suggest a substitution effect between flavored tobacco products.

Patterns of Tobacco Use and Related Protective Factors Among Somali Youth in the United States

Anti-smoking norms and educational aspirations are established tobacco prevention targets for general United States (U.S.) adolescent populations but protective factors remain poorly characterized for Somali-American youth. Here we describe patterns of past 30-day tobacco use and associated protective factors among eighth, ninth, and eleventh grade Somali adolescent respondents (n = 2009) to the 2016 Minnesota Student Survey using multivariate logistic regressions. E-cigarette (5.7%) and hookah (5.0%) use were most prevalent. Male youth reported higher levels of tobacco use across products. Adjusted odds ratios showed that internal developmental assets (e.g., e-cigarettes aOR 0.37, 95% CI 0.37, 0.79) and parental anti-smoking norms (e.g., e-cigarettes aOR 0.19, 95% CI 0.09, 0.38) protected against use of all tobacco products. E-cigarettes and hookah are prevalent among U.S. Somali youth, highlighting the need for prevention efforts that address emerging tobacco products and leverage protective factors such as internal assets and parental anti-smoking norms.

Electronic Cigarette Use and Smoking Initiation in Taiwan: Evidence from the First Prospective Study in Asia

A growing literature indicates that electronic cigarette use increases the risk of subsequent initiation of conventional smoking among cigarette-naïve adolescents in several Western countries. This research assesses the same relationship in an Asian country, Taiwan. The Taiwan Adolescent to Adult Longitudinal Study is a school-based survey that was carried out in two waves in 2014 (baseline) and in 2016 (follow-up). It employs probability sampling to create nationally representative samples of students in junior high school (mean age 13, 7th grade at baseline) and in senior high school (mean age 16, 10th grade at baseline). Data from this survey were analyzed via logistic regression to estimate the association between ever use of e-cigarettes at baseline and smoking initiation at follow-up, accounting for susceptibility to smoking, socio-demographic profile, depression status, and peer support. Among the 12,954 cigarette-naïve students surveyed, those with e-cigarette experience at baseline exhibited higher odds of smoking initiation at follow-up (Odds Ratio = 2.14, 95% CI (1.66, 2.75), p < 0.001). For the first time, we confirmed, through a longitudinal survey, a prospective association between ever use of e-cigarettes and smoking initiation in an Asian adolescent population. The restrictive policy on e-cigarettes currently in force in Taiwan is justified to prevent both e-cigarette and cigarette use among adolescents.

A new measure of youth cigarette smoking

American students' 30-day smoking prevalence has decreased dramatically over the past two decades. The frequency of smoking within the 30-day measure has shifted from heavy smoking (>1/2 pack/day) toward light smoking (<1 to 5 cigarettes/day). 30-day prevalence thus understates the extent of the decline in youth smoking. To capture this shift toward less frequent smoking among the decreasing proportion of students who smoke, I develop a new index: the average number of cigarettes smoked per student per day (ACSD), using data from Monitoring the Future. To calculate ACSD I assign a specific number of cigarettes to each of 7 response options to the question, "How frequently have you smoked cigarettes during the past 30 days?" Response options range from "not at all" (assigned 0 cigarettes) to "two packs or more per day" (assigned 45 cigarettes). I then multiply these estimates by the proportion of students giving each response option. Summing across the 7 categories produces the ACSD for that survey year. I then compare time trends in 30-day prevalence and ACSD. From the mid-1990s to 2016, 30-day smoking prevalence among 12th graders declined 71.3%, while ACSD dropped 83.9% (p < 0.001). The figures were 84.0% and 90.6% (p < 0.001) for 10th graders and 87.4% and 89.0% for 8th graders (p < 0.05). Sensitivity analysis supports the finding that ACSD has decreased more than 30-day prevalence over time for both 10th and 12th grades. ACSD provides a new measure of the decline in youth smoking to complement the traditional measure of 30-day prevalence.