Peter Hajek

Smoking rates are up to four times higher among people experiencing homelessness compared to the housed population and how to support them to quit is unclear. To test the effectiveness and cost-effectiveness of providing e-cigarettes to people accessing homeless support services to stop smoking. To explore implementation fidelity, contextual influences and mechanisms of change. A two-arm cluster randomised controlled trial with cost-effectiveness and mixed-methods process evaluation. Setting and participants: Thirty-two homeless centres (clusters) across Great Britain. Participants were aged 18+ years and known by centre staff to smoke. Sixteen staff and 31 participants in electronic cigarette centres completed qualitative interviews. Clusters were randomised (1 : 1) to electronic cigarettes or usual care prior to staff training. Electronic cigarette participants received a refillable electronic cigarette, 4 weeks' supply of e-liquid and a fact sheet. Usual care participants received very brief advice on smoking, a support leaflet and signposting to Stop Smoking Service. Primary outcome: Carbon-monoxide-verified sustained smoking abstinence from 2 weeks post baseline to 24 weeks. Secondary outcomes: Carbon-monoxide-verified 7-day point prevalence abstinence, < 50% smoking reduction, intervention costs, quality-adjusted life-years, implementation fidelity and mechanisms of change. Sixteen centres were randomised to electronic cigarettes (n = 239 participants) and 16 to usual care (n = 238 participants). In usual care, one participant died, and one withdrew consent. Final sample analysed: n = 239 (electronic cigarette); n = 236 (usual care). Sustained 24-week carbon-monoxide-verified smoking cessation rates were 5/239 (2.1%) with electronic cigarettes versus 2/236 (0.8%) with usual care (adjusted risk ratio 2.43, 95% confidence interval 0.51 to 11.64); 7-day point prevalence abstinence at 24 weeks was 15/239 (6.3%) with electronic cigarettes versus 5/236 (2.1%) with usual care (adjusted risk ratio 2.95, 95% confidence interval 1.05 to 8.29). Smoking reduction (< 50%) at 24 weeks was 83/239 (34.7%) with electronic cigarettes versus 40/236 (17%) with usual care (adjusted risk ratio 2.02, 95% confidence interval 1.44 to 2.84). Four adverse events were reported in the electronic cigarette arm; three electronic cigarette-related and not serious; one serious and not electronic cigarette-related. Mean per participant intervention costs were £92 (standard error £0) for electronic cigarettes and £50 (standard error £0) for usual care. Mean total costs were £3859 (standard error £441) versus £2716 (standard error £386) in electronic cigarette and usual care groups, respectively. Quality-adjusted life-years were estimated at 0.303 (standard error 0.008) for electronic cigarettes and 0.295 (standard error 0.010) for usual care. From National Health Service and Personal Social Services perspective, the electronic cigarette arm was £1267 (95% confidence interval £219 to £2347) more costly and yielded 0.007 (95% confidence interval -0.016 to 0.033) more quality-adjusted life-years than usual care. The incremental cost-effectiveness ratio was £181,000 per quality-adjusted life-year gain. Electronic cigarette intervention was delivered with high fidelity with no variation by centre size or location, although staff capacity and resourcing were barriers to implementation. Quit enablers included high capability to use electronic cigarettes, support from friends/family and increased motivation following smoking reduction. Barriers included lack of satisfaction with electronic cigarettes compared with smoking, a strong smoking culture at centres and staff deprioritising tobacco-related harm. Low quit rates resulted in insufficient power to detect an effect on the primary effectiveness and cost-effectiveness outcomes, leading to uncertainty. Electronic cigarettes showed no effectiveness for 24 weeks' sustained smoking abstinence; 7-day point prevalence abstinence and smoking reduction were possible, and staff can support the intervention. Longer-term and potentially different types of support and systems change are needed to support sustained abstinence. This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme as award number NIHR132158.

Background and aims: Electronic cigarettes (EC) are considered a smoking cessation tool in some countries, such as the United Kingdom, but uncertainty remains internationally over whether their benefits outweigh potential harms when used for this purpose. This overview (1) synthesised existing evidence from systematic reviews (SR) on the effectiveness and safety of ECs to explore and address these uncertainties and disagreements and (2) mapped primary intervention studies to identify priorities for further research. Methods: Overview of SRs published from 1 January 2015 and meeting the inclusion criteria of the Cochrane review of EC for smoking cessation. We searched seven databases to April 2024. We followed Cochrane screening and data extraction methods. We adapted Campbell Collaboration and 3ie methods for the Evidence and Gap Map (EGM). We assessed review quality using AMSTAR‐2. Results: We included 14 reviews of intervention studies (7 high quality; 7 low quality), with search dates from 2014 to 2023, in adult populations including the general population, people at risk of lung cancer, with comorbid health conditions and pregnant people. Eighteen studies were included across multiple reviews, some of which included multiple meta‐analyses. Across 21 meta‐analytic comparisons of nicotine EC versus other interventions, all reported point estimates favouring nicotine EC for smoking cessation, with relative risks/odds ratios typically in the range 1.17–1.67 versus nicotine replacement therapy and 1.46–2.09 versus non‐nicotine EC, with higher‐quality reviews giving more consistent estimates. Of 13 reviews that meta‐analysed serious adverse events (SAEs), two reported point estimates suggesting increased SAEs with nicotine EC; other estimates included the possibility of no difference. For adverse events, pooled estimates generally indicated little or no difference between groups. Our EGM mapped 90 primary, complete studies and identified absolute gaps in evidence comparing the effects of nicotine EC to cytisine, bupropion and nicotine pouches. Most studies used collected data from high‐income countries. Conclusion: Meta‐analyses of electronic cigarettes (EC) for smoking cessation report point estimates favouring higher ≥6‐month smoking cessation rates with nicotine EC compared with nicotine replacement therapy, non‐nicotine EC/placebo, behavioural or no support and mixed support. Evidence on serious adverse events (SAEs) remains inconclusive. Evidence gaps were identified in SAE data and in studies from low‐ and middle‐income countries.

Background and aims: Smokers quitting successfully with the help of e‐cigarettes often continue vaping. It is not known whether this promotes or prevents relapse back to smoking. This study aimed to determine whether use of e‐cigarettes after successful smoking cessation affects the probability of relapse later on. Design: Secondary analysis of a randomised controlled trial where participants received combination nicotine replacement therapy (NRT) or e‐cigarettes to compare relapse rates in the two study arms and in abstainers who did and did not use e‐cigarettes. Setting: Four stop‐smoking services in the United Kingdom. Participants: 886 smokers (median age 41, smoking on average 15 cigarettes per day, 48% female) seeking help with stopping smoking. Measurements: Main outcome was relapse to smoking by 12 months in participants who were abstinent at 4 weeks or at 6 months. Relapse was defined as abstinence at 4 weeks but not at one year or abstinence at 6 months but not at one year. Abstinence from smoking was defined as no smoking over the past 7 days. E‐cigarette use was defined as using e‐cigarettes at the time of abstinence on at least one day per week. Findings: Abstainers in the e‐cigarette arm were less likely to relapse than abstainers in the NRT arm [relative risk (RR) = 0.78, 95% confidence interval (CI) = 0.64–0.96 for relapse between 4 weeks and 1 year; RR = 0.71, 95% CI = 0.55–0.93 for relapse between 6 months and 1 year). Relapse rates over both time periods were also lower in abstainers who used e‐cigarettes compared with abstainers who did not use e‐cigarettes (RR = 0.79, 95% CI = 0.65–0.97 and RR = 0.75, 95% CI = 0.57–0.98, respectively). Conclusions: Use of e‐cigarettes after stopping smoking is associated with a reduced risk of relapse.

Background: While smoking is common among those experiencing homelessness, the effectiveness of an e-cigarette intervention to reduce smoking in this population is unclear. Objective: To determine the cost-effectiveness of providing an e-cigarette for smoking cessation in homeless support centres compared to usual care. Design and methods: A multicentre two-arm cluster randomised controlled trial, with data collection time points at baseline, 4, 12 and 24 weeks post baseline. Setting and participants: Adults (aged 18+) who smoked daily and accessed 32 homeless support centres across six areas of Great Britain received either e-cigarette intervention ( n = 239 in 16 centres) or usual care ( n = 236 in 16 centres) by centre (cluster) randomisation. Intervention: The intervention was the provision of an e-cigarette starter kit plus 4 weeks’ supply of e-liquids. The usual care comprised very brief advice for smoking cessation and signposting to local Stop Smoking Services. Main outcome measures: The total costs included costs of intervention/usual care, costs of smoking cessation outside of the trial and costs of general healthcare services use over 24 weeks. Quality-adjusted life-years were derived from EuroQol-5 Dimensions, five-level version administered at each data collection point. An incremental cost-effectiveness ratio was calculated for 24 weeks using the difference between groups in total costs and quality-adjusted life-years, with cost-effectiveness acceptability curve constructed based on bootstrap to examine uncertainty. A long-term model was employed to project a lifetime incremental cost-effectiveness ratio with probabilistic sensitivity analysis to examine uncertainty. Data sources: The analysis over 24 weeks was based on research team records and data collected via self-reported questionnaires. Unit costs for valuation were extracted from published secondary sources. The parameters of the long-term model were based on the 24-week results and published secondary sources. Results: Mean intervention costs were estimated at £92 [standard error (SE) £0] per participant and mean usual care costs at £50 (SE £0) per participant. Mean total costs per participant were estimated at £3859 (SE £441) in the e-cigarette group and £2716 (SE £386) in the usual care group. Mean quality-adjusted life-years were estimated at 0.303 (SE 0.008) in the e-cigarette group and 0.295 (SE 0.010) in the usual care group. Adjusting for baseline covariates and respective baseline values, e-cigarette group were £1267 (95% confidence interval £600 to £1938) more costly and yielded 0.007 (95% confidence interval −0.017 to 0.027) more quality-adjusted life-years than usual care. The incremental cost-effectiveness ratio was calculated at £181,000 per quality-adjusted life-year gain, with probability of intervention being cost-effective between the incremental cost-effectiveness ratio thresholds of £20,000–30,000 per quality-adjusted life-year gain at 0.9–3.5%. The lifetime model projected the incremental cost-effectiveness ratio at £38,360 per quality-adjusted life-year gained, with the probability of intervention being cost-effective between £20,000 and £30,000 from 47.6% to 49.6%. Limitations: The imbalance in missing data led to some uncertainty in the results, and healthcare costs recorded in the trial may not reflect the health needs of this population. Conclusions: Providing e-cigarettes for smoking cessation in homeless support centres was more costly than usual care, but the small increase in quality-adjusted life-years was not significant. Future work: Future work should aim to maximise quit rates while being cost-effective and therefore implementable. Funding: This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme as award number NIHR132158.

Background: Smoking prevalence among people experiencing homelessness is high. This study explored the factors which influenced potential smoking abstinence among participants receiving an e-cigarette (EC) intervention within the Smoking Cessation Trial in Centres for Homelessness (SCeTCH) across Great Britian. Methods: Using the Capability Opportunity Motivation – Behaviour (COM-B) model, hypothesised and emerging mediators were explored quantitatively via measures in baseline and follow-up questionnaires (n=239) and qualitatively via interviews with homelessness centre staff (n=16) and participants (n=31) who received an EC starter pack and 4-week e-liquid supply. We purposively sampled 8 centres for interviews, representing varied regions and participant vaping/smoking and sociodemographic status. Quantitative measures were analysed descriptively. Qualitative data were analysed thematically. Data from the two approaches were mapped onto the COM-B for combined analysis and reporting. Results: After receiving the intervention, participants demonstrated high capability to use EC and appreciation of EC for harm reduction. Some participants reported dissatisfaction with vaping. Opportunity for behaviour change was strengthened by perceived acceptability to vape and social support beyond the centre but hindered by a smoking culture and perceived lack of staff support. Motivation was enhanced by EC efficacy belief, pride from cutting down, and financial benefits of vaping, but negatively impacted by challenging personal circumstances. Conclusion: For people accessing homelessness support centres, smoking abstinence remains challenging. More intensive support and a variety of approaches to support smoking cessation, particularly those which address the psychosocial factors which hinder smoking abstinence, may be required. Future research should focus on how this can be achieved.

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Background Electronic cigarettes (ECs) are handheld electronic vaping devices that produce an aerosol by heating an e‐liquid. People who smoke, healthcare providers, and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review. Objectives To examine the safety, tolerability, and effectiveness of using EC to help people who smoke tobacco achieve long‐term smoking abstinence, in comparison to non‐nicotine EC, other smoking cessation treatments, and no treatment. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 February 2024 and the Cochrane Tobacco Addiction Group's Specialized Register to 1 February 2023, reference‐checked, and contacted study authors. Selection criteria We included trials randomizing people who smoke to an EC or control condition. We included uncontrolled intervention studies in which all participants received an EC intervention. Studies had to report an eligible outcome. Data collection and analysis We followed standard Cochrane methods for screening and data extraction. We used the risk of bias tool (RoB 1) and GRADE to assess the certainty of evidence. Critical outcomes were abstinence from smoking after at least six months, adverse events (AEs), and serious adverse events (SAEs). Important outcomes were biomarkers, toxicants/carcinogens, and longer‐term EC use. We used a fixed‐effect Mantel‐Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in pairwise and network meta‐analyses (NMA). Main results We included 90 completed studies (two new to this update), representing 29,044 participants, of which 49 were randomized controlled trials (RCTs). Of the included studies, we rated 10 (all but one contributing to our main comparisons) at low risk of bias overall, 61 at high risk overall (including all non‐randomized studies), and the remainder at unclear risk. Nicotine EC results in increased quit rates compared to nicotine replacement therapy (NRT) (high‐certainty evidence) (RR 1.59, 95% CI 1.30 to 1.93; I² = 0%; 7 studies, 2544 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6 more). The rate of occurrence of AEs is probably similar between groups (moderate‐certainty evidence (limited by imprecision)) (RR 1.03, 95% CI 0.91 to 1.17; I² = 0%; 5 studies, 2052 participants). SAEs were rare, and there is insufficient evidence to determine whether rates differ between groups due to very serious imprecision (RR 1.20, 95% CI 0.90 to 1.60; I² = 32%; 6 studies, 2761 participants; low‐certainty evidence). Nicotine EC probably results in increased quit rates compared to non‐nicotine EC (moderate‐certainty evidence, limited by imprecision) (RR 1.46, 95% CI 1.09 to 1.96; I² = 4%; 6 studies, 1613 participants). In absolute terms, this might lead to an additional three quitters per 100 (95% CI 1 to 7 more). There is probably little to no difference in the rate of AEs between these groups (moderate‐certainty evidence) (RR 1.01, 95% CI 0.91 to 1.11; I² = 0%; 5 studies, 840 participants). There is insufficient evidence to determine whether rates of SAEs differ between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I² = 0%; 9 studies, 1412 participants; low‐certainty evidence). Compared to behavioural support only/no support, quit rates may be higher for participants randomized to nicotine EC (low‐certainty evidence due to issues with risk of bias) (RR 1.96, 95% CI 1.66 to 2.32; I² = 0%; 11 studies, 6819 participants). In absolute terms, this represents an additional four quitters per 100 (95% CI 3 to 5 more). There was some evidence that (non‐serious) AEs may be more common in people randomized to nicotine EC (RR 1.18, 95% CI 1.10 to 1.27; I² = 6%; low‐certainty evidence; 6 studies, 2351 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 0.93, 95% CI 0.68 to 1.28; I² = 0%; 12 studies, 4561 participants; very low‐certainty evidence). Results from the NMA were consistent with those from pairwise meta‐analyses for all critical outcomes. There was inconsistency in the AE network, which was explained by a single outlying study contributing the only direct evidence for one of the nodes. Data from non‐randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons; hence, evidence for these is limited, with CIs often encompassing both clinically significant harm and benefit. Authors' conclusions There is high‐certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate‐certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care or no treatment also suggests benefit, but is less certain due to risk of bias inherent in the study design. Confidence intervals were, for the most part, wide for data on AEs, SAEs, and other safety markers, with no evidence for a difference in AEs between nicotine and non‐nicotine ECs nor between nicotine ECs and NRT, but low‐certainty evidence for increased AEs compared with behavioural support/no support. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but longer, larger studies are needed to fully evaluate EC safety. Our included studies tested regulated nicotine‐containing EC; illicit products and/or products containing other active substances (e.g. tetrahydrocannabinol (THC)) may have different harm profiles. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up‐to‐date information to decision‐makers, this is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Aims: The aim of this study was to examine the safety of e‐cigarettes (EC) and nicotine patches (NRT) when used to help pregnant smokers quit. Design: A recent trial of EC versus NRT reported safety outcomes in the randomized arms. We conducted a further analysis based on product use. Setting: Twenty‐three hospitals in England and a stop‐smoking service in Scotland took part. Participants: The participants comprised 1140 pregnant smokers. Interventions: We compared women using and not using EC and NRT regularly during pregnancy. Measurements: Measurements included nicotine intake compared with baseline, birth weight, other pregnancy outcomes, adverse events, maternal respiratory symptoms and relapse in early abstainers. Findings: Use of EC was more common than use of NRT (47.3% vs 21.6%, P < 0.001). Women who stopped smoking (abstainers) and used EC at the end‐of‐pregnancy (EOP) reduced their salivary cotinine by 45% [49.3 ng/ml, 95% confidence interval (CI) = −79.8 to −10]. Only one abstainer used NRT at EOP. In dual users, cotinine increased by 19% (24 ng/ml, 95% CI = 3.5–68). In women reporting a reduction of at least 50% in cigarette consumption, cotinine levels increased by 10% in those using nicotine products and by 9% in those who did not. Birth weights in dual users and exclusive smokers were the same (3.1 kg). Birth weight in abstainers using either nicotine product was higher than in smokers [3.3 kg, standard deviation (SD) = 0.7] versus 3.1 kg, SD = 0.6; difference = 0.15 kg, 95% CI = 0.05–0.25) and not different from abstainers not using nicotine products (3.1 kg, SD = 0.8). Abstainers and smokers using nicotine products had no worse pregnancy outcomes or more adverse events than abstainers and smokers not using them. EC users reported more improvements than non‐users in cough [adjusted relative risk (aRR) = 0.59, 95% CI = 0.37–0.93] and phlegm (aRR = 0.53, 95% CI = 0.31–0.92), controlling for smoking status. EC or NRT use had no association with relapse. Conclusions: Regular use of e‐cigarettes or nicotine patches by pregnant smokers does not appear to be associated with any adverse outcomes.

Background: It is not currently clear what impact alternative nicotine-delivery products (electronic cigarettes, heated tobacco products and snus) have on smoking rates and cigarette sales. Objective: To assess whether access to these products promotes smoking in the population. Design and data sources: We examined associations of alternative nicotine product use and sales with smoking rates and cigarette sales overall, and in different age and socioeconomic groups, and compared smoking prevalence over time in countries with contrasting regulations of these products. For electronic cigarettes, we examined data from countries with historically similar smoking trajectories but differing current electronic cigarette regulations (United Kingdom and United States of America vs. Australia, where sales of nicotine-containing electronic cigarettes are banned); for heated tobacco, we used data from countries with state tobacco monopolies, where cigarette and heated tobacco sales data are available (Japan, South Korea), and for snus we used data from Sweden. Analysis methods: We pre-specified dynamic time series analyses to explore associations between use and sales of alternative nicotine-delivery products and smoking prevalence and cigarette sales, and time series analyses to compare trends of smoking prevalence in countries with different nicotine product policies. Results: Because of data and analysis limitations (see below), results are only tentative and need to be interpreted with caution. Only a few findings reached statistical significance and for most results the Bayes factor indicated inconclusive evidence. We did not find an association between rates of smoking and rates of the use of alternative nicotine products. The increase in heated tobacco product sales in Japan was accompanied by a decrease in cigarette sales. The decline in smoking prevalence seems to have been slower in Australia than in the United Kingdom overall, and slower than in both the United Kingdom and the United States of America among young people and also in lower socioeconomic groups. The decline in cigarette sales has also accelerated faster in the United Kingdom than in Australia. Limitations: Most of the available data had insufficient data points for robust time series analyses. The assumption of our statistical approach that causal interactions are more likely to be detected when longer-term changes are screened out may not apply for short time series and in product interaction scenarios, where short-term fluctuations can be caused by, for example, fluctuations in prosperity or product supplies. In addition, due to dual use, prevalence figures for smoking and alternative product use overlap. The ecological study design limits the causal inferences that can be made. Longer time periods are needed for any effects of exclusive use of the new products on smoking prevalence to emerge. Conclusions: We detected some indications that alternative nicotine products are competing with cigarettes rather than promoting smoking and that regulations that allow their sales are associated with a reduction rather than an increase of smoking, but the findings are inconclusive because of insufficient data points and issues with the assumptions of the pre-specified statistical analyses. Future work: As further prevalence and sales data emerge the analyses will become more informative. Accessing sales figures in particular is the current research priority. Study registration: The project is registered on Open Science Framework https://osf.io/bd3ah. Funding: This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme (NIHR129968) and will be published in full in Public Health Research; Vol. 11, No. 7. See the NIHR Journals Library website for further project information.