Background
Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol formed by heating an e‐liquid. Some people who smoke use ECs to stop or reduce smoking, but some ...organizations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit and if they are safe to use for this purpose. This is an update conducted as part of a living systematic review.
Objectives
To examine the effectiveness, tolerability, and safety of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long‐term smoking abstinence.
Search methods
We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 May 2021, and reference‐checked and contacted study authors. We screened s from the Society for Research on Nicotine and Tobacco (SRNT) 2021 Annual Meeting.
Selection criteria
We included randomized controlled trials (RCTs) and randomized cross‐over trials, in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. Studies had to report abstinence from cigarettes at six months or longer or data on safety markers at one week or longer, or both.
Data collection and analysis
We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow‐up, adverse events (AEs), and serious adverse events (SAEs). Secondary outcomes included the proportion of people still using study product (EC or pharmacotherapy) at six or more months after randomization or starting EC use, changes in carbon monoxide (CO), blood pressure (BP), heart rate, arterial oxygen saturation, lung function, and levels of carcinogens or toxicants or both. 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 meta‐analyses.
Main results
We included 61 completed studies, representing 16,759 participants, of which 34 were RCTs. Five of the 61 included studies were new to this review update. Of the included studies, we rated seven (all contributing to our main comparisons) at low risk of bias overall, 42 at high risk overall (including all non‐randomized studies), and the remainder at unclear risk.
There was moderate‐certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (risk ratio (RR) 1.53, 95% confidence interval (CI) 1.21 to 1.93; I2 = 0%; 4 studies, 1924 participants). In absolute terms, this might translate to an additional three quitters per 100 (95% CI 1 to 6). There was low‐certainty evidence (limited by very serious imprecision) that the rate of occurrence of AEs was similar (RR 0.98, 95% CI 0.80 to 1.19; I2 = 0%; 2 studies, 485 participants). SAEs were rare, but there was insufficient evidence to determine whether rates differed between groups due to very serious imprecision (RR 1.44, 95% CI 0.94 to 2.19: I2 = 0; 3 studies, 1183 participants).
There was moderate‐certainty evidence, again limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non‐nicotine EC (RR 1.94, 95% CI 1.21 to 3.13; I2 = 0%; 5 studies, 1447 participants). In absolute terms, this might lead to an additional seven quitters per 100 (95% CI 2 to 16). There was moderate‐certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 3 studies, 601 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 0.95, 95% CI 0.52 to 1.72; I2 = 0; 6 studies, 1033 participants).
Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.61, 95% CI 1.44 to 4.74; I2 = 0%; 6 studies, 2886 participants). In absolute terms this represents an additional six quitters per 100 (95% CI 2 to 15). However, this finding was of very low certainty, due to issues with imprecision and risk of bias. There was some evidence that non‐serious AEs were more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low certainty; 4 studies, 765 participants), and again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 1.51, 95% CI 0.70 to 3.24; I2 = 0%; 7 studies, 1303 participants).
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 use. Very few studies reported data on other outcomes or comparisons, hence evidence for these is limited, with CIs often encompassing clinically significant harm and benefit.
Authors' conclusions
There is moderate‐certainty evidence that ECs with nicotine increase quit rates compared to NRT and compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the effect size. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non‐nicotine ECs. Overall incidence of SAEs was low across all study arms. We did not detect evidence of harm from nicotine EC, but longest follow‐up was two years and the number of studies was small.
The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates, but further RCTs are underway. To ensure the review continues to provide up‐to‐date information to decision‐makers, this review is now 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.
ObjectivesRecruitment in randomised controlled trials (RCTs) is a complex process and includes several stages including the assessment of potential participants for eligibility and successively ...converting the number of eligible people into consenting, randomised participants. In behavioural RCTs of smoking cessation interventions, poor recruitment is common. In our pool of trials with data available eligibility rates were 61% (95% confidence interval 54% to 66%) and recruitment rates were 69% (95% confidence interval 64% to 73%). However, evidence on which factors predicts poor recruitment in behavioural RCTs of smoking cessation interventions is limited. Individual studies have suggested that participant characteristics (e.g. older age), recruitment strategies (e.g. via internet) and intervention characteristics (e.g. face-to-face) may influence the recruitment process. Therefore, our aim was to identify predictors of eligibility and recruitment rates in smoking cessation RCTs by performing meta-regression analyses on the studies within the IC-SMOKE systematic review project.MethodThe IC-SMOKE project is a systematic reviews project of 173 behavioural RCTs of smoking cessation interventions; the protocol is published on PROSPERO (CRD42019121453). Relevant studies were identified in the Cochrane Tobacco Addiction Group Specialized Register. We identified RCTs testing behavioural interventions (with or without pharmacological support) directed at adult smokers (> 18years old) and assessing smoking cessation with a biochemically verified outcome at a minimum of 6 months follow-up between 1996 and 2018. We identified 20 potential predictors based on previous evidence of their predictive value in the published literature and consultation with experts in the field. Predictors were grouped into participant characteristics, recruitment strategy and intervention characteristics and were pre-specified with the meta-regression analyses (https://osf.io/5er49/). Univariate meta-regression analyses were used to investigate the association of predictors on logit-transformed eligibility rates (#randomised + #declined/#assessed for eligibility) and recruitment rates (#randomised/#eligible) as the outcomes.Results137 and 118 out of 173 studies had complete data and were included in the analyses for eligibility and recruitment rates, respectively. We found no evidence for the recruitment strategy (classified as targeted vs. non-targeted and direct vs. indirect or a combination of both) to predict eligibility rates. Studies including self-help interventions for smoking cessation were associated with 89% lower odds of recruiting eligible participants than person-delivered interventions for smoking cessation (OR 0.11, 95% confidence interval 0.02 to 0.54, p-value 0.007). Additionally, studies recruiting participants with an ongoing mental condition (OR 2.48, 95% confidence interval 0.93 to 6.61, p-value 0.070) and older age (OR 1.04, 95% confidence interval 0.99 to 1.09, p-value 0.094) were associated with higher, but not statistically significant, odds. Participants characteristics such as having a low socioeconomic status or being motivated to quit smoking and the recruitment strategy were not associated with recruitment rates.ConclusionsOur findings suggest that behavioural RCTs of smoking cessation that test interventions without person-to-person contact have more difficulties converting the number of eligible people into consenting, randomised participants. No other participant, recruitment strategy or intervention characteristics were found to be associated with recruitment rates. Due to considerable heterogeneity in trial recruitment and eligibility rates, this study provides little guidance other than intervention mode of delivery, to enhance these rates. Furthermore, we noted that 32% and 21% of eligible RCTs did not report enough data to allow the investigation of recruitment and eligibility rates, respectively. We encourage researchers to follow available guidelines on reporting RCTs (e.g. CONSORT-SPI) to improve reporting of recruitment data, such as the number of people approached or assessed for eligibility, so that their data can contribute to evidence on optimising RCT participation.
BACKGROUND: In Germany, we see a decline in the use of the oral contraceptive pill. Although there have been studies showing a lack of knowledge about the mode of action of the pill and alternative ...methods, the number of German women who feel well informed about the pill increased over recent years. At the same time, a trend to increasingly cover negative aspects of oral contraception has emerged in German journalism and social media. OBJECTIVE: This study aimed to consider the relationship between the source of information about the pill, subjective and objective knowledge, and how their interaction influences perceptions of the pill. STUDY DESIGN: An online survey was conducted of 18- to 29-year-old women to test their objective and subjective knowledge, their perception of oral contraceptives, and their trust in gynecologists. The recruitment took place online and in gynecologic practices. The survey opened in September 2020 and closed in April 2021. RESULTS: A total of 2470 women completed the survey. The most common sources of information were the internet (80%), the gynecologist (47%), and friends and family (47%). Women reporting the internet as a source of information were more likely to have lower perception and trust rates, and less likely to overestimate their own knowledge. The findings suggest that school or university as a source of information has a positive effect on decision-making and general attitude toward information received by gynecologists about oral contraceptives. Those with higher confidence in their knowledge are likely to have a more positive attitude and higher levels of trust. CONCLUSION: A feeling of uncertainty, instead of fixed assumptions gathered from unsophisticated sources, affects perception regarding oral contraceptives and trust toward gynecologists negatively. Gynecologists and educators should hence increase efforts to meet potential needs for discussing uncertainties to prevent further loss of confidence.
Background: The majority of adults in the UK are overweight or obese, and many embark on weight loss attempts, often without professional support. This dissertation set out to hone in on the ...cognitive and behavioural strategies used by adults with overweight and obesity attempting to lose weight, particularly in self-guided attempts, and to test the relationship between use of these strategies and weight loss success. Methods: A new taxonomy and questionnaire were developed to provide a framework to identify the cognitive and behavioural strategies used by individuals during weight loss attempts. The taxonomy was used in a systematic review and meta-analysis of self-help interventions for weight loss and in a systematic review of qualitative studies of self-directed weight loss. The questionnaire was used in an observational cohort study in adults with overweight and obesity trying to lose weight. Results: The taxonomy and questionnaire consist of 117 strategies. The qualitative review illuminated a range of attitudes and beliefs towards these strategies and highlighted the centrality of interpretation of self-monitored data. The quantitative review found that self-help interventions led to greater weight loss than unsupported attempts to lose weight at six months. In the cohort study, despite heterogeneity in the strategies employed, coherent patterns of behaviours emerged for individual participants. Strategies related to motivational support, dietary impulse control, and weight loss planning and monitoring were associated with greater weight loss. Conclusion: This dissertation demonstrates that self-help interventions can lead to significant weight loss and provides results to guide the content of such interventions. It maps out a previously uncharted area and provides a set of tools for further research and intervention development.
Background: The majority of adults in the UK are overweight or obese, and many embark on weight loss attempts, often without professional support. This dissertation set out to hone in on the ...cognitive and behavioural strategies used by adults with overweight and obesity attempting to lose weight, particularly in self-guided attempts, and to test the relationship between use of these strategies and weight loss success. Methods: A new taxonomy and questionnaire were developed to provide a framework to identify the cognitive and behavioural strategies used by individuals during weight loss attempts. The taxonomy was used in a systematic review and meta-analysis of self-help interventions for weight loss and in a systematic review of qualitative studies of self-directed weight loss. The questionnaire was used in an observational cohort study in adults with overweight and obesity trying to lose weight. Results: The taxonomy and questionnaire consist of 117 strategies. The qualitative review illuminated a range of attitudes and beliefs towards these strategies and highlighted the centrality of interpretation of self-monitored data. The quantitative review found that self-help interventions led to greater weight loss than unsupported attempts to lose weight at six months. In the cohort study, despite heterogeneity in the strategies employed, coherent patterns of behaviours emerged for individual participants. Strategies related to motivational support, dietary impulse control, and weight loss planning and monitoring were associated with greater weight loss. Conclusion: This dissertation demonstrates that self-help interventions can lead to significant weight loss and provides results to guide the content of such interventions. It maps out a previously uncharted area and provides a set of tools for further research and intervention development.
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