Electronic cigarette (e-cigarette) use is associated with smoking initiation among young people; however, it is also possible that smoking is associated with e-cigarette initiation. This study explores these associations among young people in Great Britain. A longitudinal survey of 1,152 11- to 18-year-olds was conducted with baseline in April 2016 and follow-up between August and October 2016. Logistic regression models and causal mediation analyses assessed whether (1) ever e-cigarette use and escalation were associated with smoking initiation (ever smoking at follow-up) among baseline never smokers (n = 923), and (2) ever smoking and escalation were associated with e-cigarette initiation (ever e-cigarette use at follow-up) among baseline never e-cigarette users (n = 1,020). At baseline, 19.8% were ever smokers and 11.4% were ever e-cigarette users. Respondents who were ever e-cigarette users (vs. never users, 53% vs. 8%, odds ratio [OR] = 11.89, 95% confidence interval [CI] = 3.56-39.72) and escalated their e-cigarette use (vs. did not, 41% vs. 8%, OR = 7.89, 95% CI = 3.06-20.38) were more likely to initiate smoking. Respondents who were ever smokers (vs. never smokers, 32% vs. 4%, OR = 3.54, 95% CI = 1.68-7.45) and escalated their smoking (vs. did not, 34% vs. 6%, OR = 5.79, 95% CI = 2.55-13.15) were more likely to initiate e-cigarette use. There was a direct effect of ever e-cigarette use on smoking initiation (OR = 1.34, 95% CI = 1.05-1.72), and ever smoking on e-cigarette initiation (OR = 1.08, 95% CI = 1.01-1.17); e-cigarette and smoking escalation, respectively, did not mediate these effects. Among young people in Great Britain, ever e-cigarette use is associated with smoking initiation, and ever smoking is associated with e-cigarette initiation.

Background and aims: Social norms towards smoking are a key concept in tobacco control policy and research. However, the influence and strength of different types of social norms on youth smoking uptake is unclear. This study aimed to examine, quantify and compare evidence of the longitudinal associations between different types of social norms towards smoking and youth smoking uptake (initiation and escalation). Methods: Systematic review searching four databases (MEDLINE, EMBASE, PsycInfo, CINAHL) from January 1998 to October 2020. Evidence synthesis via narrative review, meta‐analysis pooling unadjusted associations (initiation only, due to heterogeneity in escalation outcomes) and meta‐regression comparing effect sizes by norm type and study characteristics. Studies included observational prospective cohort studies using survey methodology with youth aged ≤24 years. Measurements included longitudinal associations between descriptive norms (perceived smoking behaviour) and injunctive norms (perceived approval/disapproval of smoking) among social network(s) and subsequent smoking initiation or escalation. Results: Thirty articles were identified. In the narrative review, smoking initiation (but not escalation) was consistently predicted by two norms: parental and close friend smoking. Associations between smoking uptake and other descriptive norms (smoking among siblings, family/household, partner, peers, adults) and all injunctive norms (perceived approval of smoking among parents, siblings, close friends/peers, partner, teachers, people important to you, the public) were less consistent or inconclusive. In the meta‐analysis pooling unadjusted associations, 17 articles were included ( n = 27 767). Smoking initiation was predicted by the following descriptive norms: smoking among parents [Odds Ratio (OR) = 1.88, 95% Confidence Interval (CI) = 1.56–2.28], close friends (OR = 2.53, 95% CI = 1.99–3.23), siblings (OR = 2.44, 95% CI = 1.93–3.08), family/household (OR = 1.55, 95% CI = 1.36–1.76) and adults (OR = 1.34, 95% CI = 1.02–1.75), but not peers (OR = 1.14, 95% CI = 0.92–1.42). Smoking initiation was also predicted by two injunctive norms, perceived approval of smoking among parents (OR = 1.74, 95% CI = 1.27–2.38) and the public (OR = 4.57, 95% CI = 3.21–6.49), but not close friends/peers (OR = 2.36, 95% CI = 0.86–6.53) or people important to the individual (OR = 1.24, 95% CI = 0.98–1.58). Conclusions: In this systematic review (narrative and meta‐analysis), descriptive norms of parents’ and close friends’ smoking behaviour appeared to be consistent predictors of youth smoking initiation, more so than the descriptive norms of more distal social networks and injunctive norms.

Background and Aims: Heated tobacco products (HTPs) are electronic devices that heat process tobacco to release an aerosol containing nicotine and other chemicals. Limited data exist on world‐wide HTP use prevalence. This meta‐analytic review estimated the prevalence of HTP use by country, World Health Organization (WHO) region, year, sex/gender and age.Methods: Five databases (Web of Science, Scopus, Embase, PubMed and PsycINFO) were searched between January 2015 and May 2022. Included studies reported the prevalence of HTP use in nationally representative samples post‐modern HTP device market entry (2015). A random‐effects meta‐analysis was used to estimate overall prevalence for life‐time, current and daily HTP use.Results: Forty‐five studies (n = 1 096 076) from 42 countries/areas from the European Region (EUR), Western Pacific Region (WPR), Region of the Americas (AMR) and African Region (AFR) met inclusion criteria. Estimated pooled prevalence for life‐time, current and daily HTP use was 4.87% [95% confidence interval (CI) = 4.16, 5.63], 1.53% (95% CI = 1.22, 1.87) and 0.79% (95% CI = 0.48, 1.18), respectively, across all years (2015–22). Life‐time HTP use prevalence significantly increased by 3.39% for WPR [0.52% (95% CI = 0.25, 0.88) in 2015 to 3.91% (95% CI = 2.30, 5.92) in 2019] and 5.58% for EUR [1.13% (95% CI = 0.59, 1.97) in 2016 to 6.98% (95% CI = 5.69, 8.39) in 2020]. Current HTP use increased by 10.45% for WPR [0.12% (95% CI = 0, 0.37) in 2015 to 10.57% (95% CI = 5.59, 16.88) in 2020] and 1.15% for EUR [0% (95% CI = 0, 0.35) in 2016 to 1.15% (95% CI = 0.87, 1.47) in 2020]. Meta‐regression revealed higher current HTP use in WPR [3.80% (95% CI = 2.88, 4.98)] compared with EUR [1.40% (95% CI = 1.09, 1.74)] and AMR [0.81% (95% CI = 0.46, 1.26)] and for males [3.45% (95% CI = 2.56, 4.47)] compared with females [1.82% (95% CI = 1.39, 2.29)]. Adolescents had higher life‐time HTP use prevalence [5.25% (95% CI = 4.36, 6.21) than adults [2.45% (95% CI = 0.79, 4.97)]. Most studies scored a low risk of sampling bias due to their nationally representative sampling.Conclusion: The prevalence of HTPs use increased in the EUR and WPR between 2015 and 2020, with nearly 5% of the included populations having ever tried HTP and 1.5% identifying as current users during the study period.

This study assesses differences in social norms towards smoking and vaping among youth across countries (England, Canada, US) and smoking and vaping status. Data are from the 2017 ITC Youth Tobacco and Vaping Survey, among youth age 16-19 in England (N = 3444), Canada (N = 3327), and US (N = 3509). Prevalence of friend smoking, friend vaping, peer approval of smoking, and peer approval of vaping were estimated. Adjusted logistic regression models were estimated for each norm to assess associations with country, smoking status, and vaping status, adjusting for sociodemographics, alcohol use, and marijuana use. 47% and 52% reported friend smoking and vaping respectively. Perceived peer approval of vaping (44%) was almost double that of smoking (23%). Compared with England, fewer Canadian and US youth reported friend smoking (Canada: AOR = 0.71 [95% CI = 0.62-0.82]; US: AOR = 0.54 [0.47-0.62]) and peer approval of smoking (Canada: AOR = 0.74 [0.63-0.87]; US: AOR = 0.78 [0.67-0.91]), yet more reported peer approval of vaping (Canada: AOR = 1.23 [1.08-1.41]; US: AOR = 1.30 [1.14-1.48]). More Canadian than English youth reported friend vaping (AOR = 1.17 [1.02-1.36]). Friend smoking, peer approval of smoking, and friend vaping were more common among smokers and vapers (all p < .02). Peer approval of vaping was more common among vapers but less common among smokers (all p < .044). Youth had more positive vaping than smoking norms. English youth reported the most pro-smoking but least pro-vaping norms in adjusted models; this was unexpected given country differences in regulatory environments. Norms towards both products were associated with use, with some evidence of cross-product associations between norms and behaviours.

E-cigarettes often contain nicotine without the most harmful constituents of tobacco smoke. This study aims to assess prevalence and correlates of accurately perceiving e-cigarettes as less harmful than cigarettes and that none or a small amount of the harm from smoking comes from nicotine. Cross-sectional survey of 2,103 11-18-year-olds in Great Britain in 2016. Prevalence of e-cigarette and nicotine harm perceptions were calculated. Logistic regressions assessed associations between accurate e-cigarette and nicotine harm perceptions and smoking, e-cigarette use, gender, age, region, social grade, family smoking, family e-cigarette use, smoking friends, public approval of smoking, and public approval of e-cigarettes. Associations between accurate e-cigarette and nicotine harm perceptions were also assessed. Most (63.4%) accurate e-cigarette harm perceptions were higher among those aged 16+ (OR = 1.89 [95%CI = 1.45-2.47]), 14-15 (OR = 1.29 [1.00-1.65]), who tried/used an e-cigarette sometimes (OR = 1.51 [1.03-2.21]), with family e-cigarette use (OR = 2.11 [1.46-3.04]), who perceived public disapproval of smoking (OR = 2.11 [1.18-3.77]) and approval of e-cigarettes (OR = 2.44 [1.73-3.45]), and with accurate nicotine harm perceptions (OR = 2.05 [1.28-3.28]). Accurate nicotine harm perceptions were higher among those aged 16+ (OR = 2.60 [1.62-4.16]), from North England (OR = 1.87 [1.02-3.43]) and Wales/Scotland (OR = 2.61 [1.35-5.03]) vs. London, with family smoking (OR = 1.59 [1.05-2.42]), and with accurate e-cigarette harm perceptions (OR = 2.12 [1.32-3.41]). Many young people have inaccurate harm perceptions of e-cigarettes and nicotine. Accurate e-cigarette and nicotine harm perceptions were associated with one another. E-cigarette use was associated with accurate e-cigarette but not nicotine harm perceptions; smoking was not associated with either.