Objective To review peer-reviewed evidence on heat-not-burn tobacco products (HnB), their secondhand emissions and use by humans; to identify differences between independent and industry-funded studies. Data sources Medline, Embase, PsycINFO, ProQuest, Scopus and Web of Science databases were searched up to 6 November 2017 for studies on HnB published after December 2009; reference lists were screened and other researchers contacted, yielding 637 records. Study selection Thirty-one publications on HnB secondhand emissions (n=16) or use by humans (n=15) were selected by two reviewers with excellent agreement (k=0.75). Data extraction Data on authors’ affiliations, HnB products, secondhand emissions and human exposure were extracted by one reviewer. Two reviewers assessed the quality of experimental HnB studies using the Effective Public Health Practice Project tool. Data synthesis Twenty out of 31 studies were affiliated with tobacco industry. Studies on secondhand emissions varied by methodology, products and comparators. Compared with cigarettes, HnB delivered up to 83% of nicotine and reduced levels of harmful and potentially harmful toxicants by at least 62% and particulate matter by at least 75%. Experimental HnB use studies were limited to one product, reductions of human exposure to toxicants varied between 42% and 96%. HnB use suppressed urges to smoke, but participants rated HnB less satisfying than cigarettes. While limited by methodological heterogeneity, findings were largely similar for independent and industry-funded studies. Conclusions Studies on HnB secondhand emissions and human use were heterogeneous and largely affiliated with the manufacturers. HnB exposed users and bystanders to toxicants, although at substantially lower levels than cigarettes.

Aims: To use a unique longitudinal data set to assess the association between e‐cigarette use while smoking with smoking cessation attempts, cessation and substantial reduction, taking into account frequency of use and key potential confounders.Design: Web‐based survey, baseline November/December 2012, 1‐year follow‐up in December 2013.Setting: Great Britain.Participants: National general population sample of 4064 adult smokers, with 1759 (43%) followed‐up.Measurements: Main outcome measures were cessation attempt, cessation and substantial reduction (≥50% from baseline to follow‐up) of cigarettes per day (CPD). In logistic regression models, cessation attempt in the last year (analysis n = 1473) and smoking status (n = 1656) at follow‐up were regressed on to baseline e‐cigarette use (none, non‐daily, daily) while adjusting for baseline socio‐demographics, dependence and nicotine replacement (NRT) use. Substantial reduction (n = 1042) was regressed on to follow‐up e‐cigarette use while adjusting for baseline socio‐demographics and dependence and follow‐up NRT use.Findings: Compared with non‐use, daily e‐cigarette use at baseline was associated with increased cessation attempts [odds ratio (OR) = 2.11, 95% confidence interval (CI) = 1.24–3.58, P = 0.006], but not with cessation at follow‐up (OR = 0.62, 95% CI = 0.28–1.37, P = 0.24). Non‐daily use was not associated with cessation attempts or cessation. Daily e‐cigarette use at follow‐up was associated with increased odds of substantial reduction (OR = 2.49, 95% CI = 1.14–5.45, P = 0.02), non‐daily use was not.Conclusions: Daily use of e‐cigarettes while smoking appears to be associated with subsequent increases in rates of attempting to stop smoking and reducing smoking, but not with smoking cessation. Non‐daily use of e‐cigarettes while smoking does not appear to be associated with cessation attempts, cessation or reduced smoking.

Media presentations of e-cigarettes may affect perception of the devices which may influence use. To assess in a cohort of past-year smokers (1) if perceived harm of e-cigarettes relative to cigarettes changed over time, (2) predictors of perceived relative harm, (3) if perceived relative harm predicted subsequent e-cigarette use among never-users. Longitudinal web-based survey of a general population sample of British smokers and ex-smokers, waves in 2012 (n=4553), 2013 and 2014 (44%, 31% response rate, respectively). Changes over time were assessed using Friedman and McNemar tests, n=1204. Perceived relative harm at wave 3 was regressed onto perceived relative harm at waves 1 and 2, while adjusting for socio-demographics and change in smoking and e-cigarette status, n=1204. Wave 2 e-cigarette use among 1588 wave 1 never-users was regressed onto wave 1 socio-demographics, smoking status and perceived relative harm. Perceived relative harm changed (χ(2)=20.67, p<0.001); the proportion perceiving e-cigarettes to be less harmful than cigarettes decreased from 2013 to 2014 (χ(2)=16.55, p<0.001). Previous perception of e-cigarettes as less harmful, having tried e-cigarettes and having stopped smoking between waves predicted perceiving e-cigarettes as less harmful than cigarettes. Perceiving e-cigarettes to be less harmful than cigarettes predicted subsequent use, adjusting for other characteristics (OR=1.39; 95% CI: 1.08-1.80, p=0.011). Among a cohort of smokers and ex-smokers, accurately perceiving e-cigarettes as less harmful than smoking predicted subsequent e-cigarette use in never-users; this perception declined over time. Clear information on the relative harm of cigarettes and e-cigarettes is needed.

Background. Smoking is more prevalent among people with depression. Depression may make cessation more difficult and cessation may affect depression sym

Background and aims: E‐cigarettes (EC) and nicotine replacement therapy (NRT) are less harmful than smoking, but misperceptions of relative harm are common. Aims were to (1) assess nicotine knowledge and perceptions of: harm of EC and NRT relative to smoking, addictiveness of EC relative to smoking, and change in harm to user if smoking replaced with EC; (2) define associations of these perceptions with respondent characteristics including nicotine knowledge; and (3) explore perceived main harms of EC and whether these differ by vaping status.Design: Analyses were: (1) frequencies; (2) logistic regressions of perceptions of relative harm, addictiveness and change in harm onto demographics, smoking and vaping status and nicotine knowledge (attributing cancer or health risks of smoking to nicotine); and (3) frequencies and χ² statistics.Setting and participants: Participants were smokers and recent ex‐smokers from one wave (September 2017) of a longitudinal online survey in the United Kingdom (n = 1720).Measurements: Demographics included gender, age, smoking status, vaping status and income. Survey questions collected data on nicotine knowledge and harm perceptions of different products; the relative harm perceptions of NRT, EC and tobacco cigarettes; and perceived main harms of EC.Findings: Relative to smoking, 57.3% perceived EC and 63.4% NRT to be less harmful; 25.4% perceived EC to be less addictive; and 32.2% thought replacing smoking with EC reduced health harms a great deal. Participants were less likely to endorse these beliefs if they had never vaped, and participants who had inaccurate nicotine knowledge were less likely to endorse all these beliefs apart from the addictiveness of EC. The main concerns about EC were a lack of research (48.3%), regulation or quality control (37.8%) and harmfulness of chemicals (41.6%).Conclusions: Large proportions of UK smokers and ex‐smokers overestimate the relative harmfulness of e‐cigarettes and nicotine replacement therapy compared with smoking; misattributing smoking harms to nicotine is associated with increased misperceptions.