A systematic review of predictors of vaping cessation among young people.

INTRODUCTION: Understanding the factors influencing vaping cessation among young people is crucial for targeted interventions. This review aimed to summarize the individual and environmental factors that predict vaping cessation related behaviours in the young population. METHODS: We systematically searched five databases for studies investigating predictors of vaping cessation behaviours among young people aged 10-35 years. Studies that examined predictors of cessation of cigarettes, other tobacco products, cannabis vaping, and studies evaluating efficacy of cessation interventions were excluded. Quality in Prognosis Studies tool was used to assess risk of bias. RESULTS: We found 24 studies analyzing predictors of intention to quit vaping (n=15), quit attempts (n=11), and vaping abstinence (n=7). Most studies had low risk of bias, except for study attrition. We identified 107 predictors and grouped them into 'probable', 'possible', 'insufficient evidence', 'probably unrelated', and 'inconsistent direction' categories. For 'probable' predictors, we found 11 for intention to quit, 8 for quit attempts and 5 for vaping abstinence. Overall, harm perception of vaping, current other tobacco products use, frequency of use, and level of nicotine dependence were common 'probable' predictors across three outcomes, with low harm perception of vaping, dual use, and poly tobacco use associated with decreased intention to quit and quit attempts in younger population (~10-19 years). CONCLUSIONS: Predictive modelling studies investigating vaping cessation related behaviours among young people is still limited. Future research should specifically study the natural history of vaping in youth in different jurisdictions, populations, and age groups to expand our knowledge on this area. IMPLICATIONS: We identified and categorized predictors of intention to quit vaping, quit attempts, and vaping abstinence among young people. While the 'probable' predictors can inform public health and policymakers to plan targeted vaping cessation programs for high-risk populations, raising public harm perception of vaping and encouraging to quit other tobacco products might increase intention to quit and quit attempts among younger population. However, the 'possible', 'insufficient evidence' and 'inconsistent direction' predictors needs further testing by future prospective longitudinal research. Additionally, we emphasized the significance of appropriate study designs, conducting research across various jurisdictions, and different population groups to obtain comprehensive insights.

Prevalence of post-traumatic stress disorder and depressive symptoms among civilians residing in armed conflict-affected regions: a systematic review and meta-analysis.

Background: Globally, populations afflicted by armed conflict are known to have high rates of mental health disorders. Aims: This meta-analysis aims to estimate the prevalence of post-traumatic stress disorder (PTSD) and depressive symptoms among civilians residing in armed conflict-affected regions. Methods: This meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A literature search employing MEDLINE(R), Embase Classic+Embase, APA PsycINFO, Ovid Healthstar, Journal@Ovid Full Text, Cochrane, PTSDpubs and CINAHL was conducted from inception until 19 March 2024 to identify relevant studies. Quality assessment was performed using the Joanna Briggs Institute Critical Appraisal Checklist for Prevalence Studies, and a Comprehensive Meta-Analysis was used to conduct the statistical analysis. Results: The search yielded 38 595 articles, of which 57 were considered eligible for inclusion. The included studies comprised data from 64 596 participants. We estimated a prevalence of 23.70% (95% CI 19.50% to 28.40%) for PTSD symptoms and 25.60% (95% CI 20.70% to 31.10%) for depressive features among war-afflicted civilians. The subgroup analysis based on time since the war and the country's economic status revealed the highest prevalence for both PTSD and depressive symptoms was present during the years of war and in low/middle-income countries. Conclusions: The results of this study provide conclusive evidence of the detrimental impacts of armed conflict on mental health outcomes. Hence, it is crucial to emphasise the significance of both physical and mental health in the aftermath of war and take appropriate humanistic measures to overcome challenges in the management of psychiatric illnesses. PROSPERO registration number: CRD42023416096.

An overview of systematic reviews on predictors of smoking cessation among young people.

Understanding the factors that influence smoking cessation among young people is crucial for planning targeted cessation approaches. The objective of this review was to comprehensively summarize evidence for predictors of different smoking cessation related behaviors among young people from currently available systematic reviews. We searched six databases and reference lists of the included articles for studies published up to October 20, 2023. All systematic reviews summarizing predictors of intention to quit smoking, quit attempts, or smoking abstinence among people aged 10-35 years were included. We excluded reviews on effectiveness of smoking cessation intervention; smoking prevention and other smoking behaviors; cessation of other tobacco products use, dual use, and polysubstance use. We categorized the identified predictors into 5 different categories for 3 overlapping age groups. JBI critical appraisal tool and GRADE-CERqual approach were used for quality and certainty assessment respectively. A total of 11 systematic reviews were included in this study; all summarized predictors of smoking abstinence/quit attempts and two also identified predictors of intention to quit smoking. Seven reviews had satisfactory critical appraisal score and there was minimal overlapping between the reviews. We found 4 'possible' predictors of intention to quit smoking and 119 predictors of smoking abstinence/quit attempts. Most of these 119 predictors were applicable for ~10-29 years age group. We had moderate confidence on the 'probable', 'possible', 'insufficient evidence', and 'inconsistent direction' predictors and low confidence on the 'probably unrelated' factors. The 'probable' predictors include a wide variety of socio-demographic factors, nicotine dependence, mental health, attitudes, behavioral and psychological factors, peer and family related factors, and jurisdictional policies. These predictors can guide improvement of existing smoking cessation interventions or planning of new targeted intervention programs. Other predictors as well as predictors of intention to quit smoking need to be further investigated among adolescents and young adults separately.

Effectiveness of the Wellness Together Canada Portal as a Digital Mental Health Intervention in Canada: Protocol for a Randomized Controlled Trial.

BACKGROUND: The Wellness Together Canada (WTC) portal is a digital mental health intervention that was developed in response to an unprecedented rise in mental health and substance use concerns due to the COVID-19 pandemic, with funding from the Government of Canada. It is a mental health and substance use website to support people across Canada providing digital interventions and services at no cost. Two million people have visited the WTC portal over the course of 1 year since launching; however, rigorous evaluation of this potential solution to access to mental health care during and after the COVID-19 pandemic is urgently required. OBJECTIVE: This study aims to better understand the effectiveness of the existing digital interventions in improving population mental health in Canada. METHODS: The Let's Act on Mental Health study is designed as a longitudinal fully remote, equally randomized (1:1), double-blind, alternative intervention-controlled, parallel-group randomized controlled trial to be conducted between October 2023 and April 2024 with a prospective follow-up study period of 26 weeks. This trial will evaluate whether a digital intervention such as the WTC improves population mental health trajectories over time. RESULTS: The study was approved by the research ethics board of CAMH (Centre for Addiction and Mental Health, Toronto, Ontario, Canada). It is ongoing and participant recruitment is underway. As of August 2023, a total of 453 participants in the age group of 18-72 years have participated, of whom 70% (n=359) are female. CONCLUSIONS: This initiative provides a unique opportunity to match people's specific unmet mental health and substance use needs to evidence-based digital interventions.

Factors associated with the use of psychedelics, ketamine and MDMA among sexual and gender minority youths in Canada: a machine learning analysis.

BACKGROUND: Substance use is increasing among sexual and gender minority youth (SGMY). This increase may be due to changes in social norms and socialisation, or due to SGMY exploring the potential therapeutic value of drugs such as psychedelics. We identified predictors of psychedelics, MDMA and ketamine use. METHODS: Data were obtained from 1414 SGMY participants who completed the ongoing longitudinal 2SLGBTQ+ Tobacco Project in Canada between November 2020 to January 2021. We examined the association between 80 potential features (including sociodemographic factors, mental health-related factors and substance use-related factors) with the use of psychedelics, MDMA and ketamine in the past year. Random forest classifier was used to identify the predictors most associated with reported use of these drugs. RESULTS: 18.1% of participants have used psychedelics in the past year; 21.9% used at least one of the three drugs. Cannabis and cocaine use were the predictors most strongly associated with any of these drugs, while cannabis, but not cocaine use, was the one most associated with psychedelic use. Other mental health and 2SLGBTQ+ stigma-related factors were also associated with the use of these drugs. CONCLUSION: The use of psychedelics, MDMA and ketamine among 2SLGBTQ+ individuals appeared to be largely driven by those who used them together with other drugs. Depression scores also appeared in the top 10 factors associated with these illicit drugs, suggesting that there were individuals who may benefit from the potential therapeutic value of these drugs. These characteristics should be further investigated in future studies.

E-Cigarette Dependence and Depressive Symptoms Among Youth.

INTRODUCTION: Although the relationship between smoking and depression has been well-established, little is known about the association between use of e-cigarette and depression, particularly among youth and young adults. This study proposes that e-cigarette dependence, rather than simply use, serves as a potential stressor and may interact with pre-existing vulnerabilities to contribute to depression in youth, consistent with the diathesis-stress theory. This study examines the longitudinal association of vaping dependence and vaping frequency on depression symptoms among youth and young adults who have never smoked cigarettes. METHODS: People who used e-cigarettes in the past month who reported never smoking a cigarette (N=1,226) aged between 16 and 25 years were followed longitudinally every 3 months for up to 1 year beginning in 2020. The Penn State E-Cigarette Dependence Index at time t was used to predict depression symptoms assessed using the Center for Epidemiologic Studies Depression Scale at time t+1. RESULTS: A total of 32.1% reported vaping in the past month with the Penn State E-Cigarette Dependence Index score (M=8.5) and a Center for Epidemiologic Studies Depression Scale score (M=15.8). Higher vaping dependence scores were significantly associated with increased depression symptoms scores at follow-up among youth and adults (ß=0.08; 95% CI=0.01, 0.15), controlling for baseline depression symptom scores and covariates. Although vaping dependence was highly associated with vaping frequency level, no significant association between the frequency of vaping and depression was found (ß= -0.33; 95% CI= 1.21, 0.54). CONCLUSIONS: These results are consistent with the diathesis-stress model of the relationship between substance use and depression. Vaping dependence but not vaping frequency was associated with increased depressive symptoms among people who never smoked cigarettes.

Effect of Postal-Mailed Nicotine Patches on Tobacco Cessation Among Smokers in Rural Canada: A Randomized Clinical Trial.

This randomized clinical trial assesses the efficacy of mailed nicotine patches on cessation of tobacco smoking among adults in rural Canada.

Table 2 Fallacy in Descriptive Epidemiology: Bringing Machine Learning to the Table.

There is a lack of rigorous methodological development for descriptive epidemiology, where the goal is to describe and identify the most important associations with an outcome given a large set of potential predictors. This has often led to the Table 2 fallacy, where one presents the coefficient estimates for all covariates from a single multivariable regression model, which are often uninterpretable in a descriptive analysis. We argue that machine learning (ML) is a potential solution to this problem. We illustrate the power of ML with an example analysis identifying the most important predictors of alcohol abuse among sexual minority youth. The framework we propose for this analysis is as follows: (1) Identify a few ML methods for the analysis, (2) optimize the parameters using the whole data with a nested cross-validation approach, (3) rank the variables using variable importance scores, (4) present partial dependence plots (PDP) to illustrate the association between the important variables and the outcome, (5) and identify the strength of the interaction terms using the PDPs. We discuss the potential strengths and weaknesses of using ML methods for descriptive analysis and future directions for research. R codes to reproduce these analyses are provided, which we invite other researchers to use.

A longitudinal investigation of the effects of the COVID-19 pandemic on 2SLGBTQ+ youth experiencing homelessness.

INTRODUCTION: The objective of this study was to examine the impacts of the coronavirus 2019 (COVID-19) pandemic on various dimensions of wellbeing among 2SLGBTQ+ youth experiencing homelessness over a 12-month period during the COVID-19 pandemic. METHODS: 2SLGBTQ+ youth (recruited using a convenience sampling method) participated in three online surveys to assess mental health (depression, anxiety, suicidality), substance and alcohol use, health care access, and violence for 12-months between 2021-2022. Quantitative data analysis included non-parametric one-sample proportion tests, paired t-test and McNemar's test. Longitudinal data collected across all three timepoints were treated as paired data and compared to baseline data using non-parametric exact multinomial tests, and if significant, followed by pairwise post-hoc exact binomial tests. For the purposes of analysis, participants were grouped according to their baseline survey based on pandemic waves and public health restrictions. RESULTS: 2SLGBTQ+ youth experiencing homelessness (n = 87) reported high rates of mental health challenges, including anxiety and depression, over 12-months during the pandemic. Youth participants reported experiencing poor mental health during the early waves of the pandemic, with improvements to their mental health throughout the pandemic; however, results were not statistically significant. Likewise, participants experienced reduced access to mental health care during the early waves of the pandemic but mental health care access increased for youth throughout the pandemic. CONCLUSION: Study results showed high rates of mental health issues among 2SLGBTQ+ youth, but reduced access to mental health care, due to the COVID-19 pandemic. Findings highlight the need for 2SLGBTQ+ inclusive and affirming mental health care and services to address social and mental health issues that have been exacerbated by the pandemic.

Evaluating Web-Based Care for Mental Health and Substance Use Issues for Lesbian, Gay, Bisexual, Transgender, Queer, Questioning, and 2-Spirit Youths in the Context of the COVID-19 Pandemic: Community-Based Participatory Research Study.

BACKGROUND: Mental health (MH) and substance use (SU) care supports are often difficult to access for the lesbian, gay, bisexual, transgender, queer, questioning, and 2-spirit (LGBTQ2S+) population. There is little known on how the shift to web-based care has affected and changed the experiences of LGBTQ2S+ youths within the MH care system. OBJECTIVE: This study sought to examine how web-based care modalities have affected access to care and quality of care for LGBTQ2S+ youths seeking MH and SU services. METHODS: Researchers used a web-based co-design method to explore this population's relationship with MH and SU care supports, focusing on the experiences of 33 LGBTQ2S+ youths and their relationship with MH and SU supports during the COVID-19 pandemic. A participatory design research method was used to gain experiential knowledge of LGBTQ2S+ youths' lived experience with accessing MH and SU care. Thematic analysis was used to examine the resulting audio-recorded data transcripts and create themes. RESULTS: Themes related to web-based care included accessibility, web-based communication, provision of choice, and provider relationship and interactions. Barriers to care were identified in particular for disabled youths, rural youths, and other participants with marginalized intersecting identities. Unexpected benefits of web-based care were also found and emphasize the idea that this modality is beneficial for some LGBTQ2S+ youths. CONCLUSIONS: During the COVID-19 pandemic, a time where MH- and SU-related problems have increased, programs need to reevaluate current measures so that the negative effects of web-based care modalities can be reduced for this population. Implications for practice encourage service providers to be more empathetic and transparent when providing services for LGBTQ2S+ youths. It is suggested that LGBTQ2S+ care should be provided by LGBTQ2S+ folks or organizations or service providers who are trained by LGBTQ2S+ community members. Additionally, hybrid models of care should be established in the future so that LGBTQ2S+ youths have the option to access in-person services, web-based ones, or both as there can be benefits to web-based care once it has been properly developed. Implications for policy also include moving away from a traditional health care team model and developing free and lower-cost services in remote areas.

A Machine Learning Approach Reveals Distinct Predictors of Vaping Dependence for Adolescent Daily and Non-Daily Vapers in the COVID-19 Era.

Since 2016, there has been a substantial rise in e-cigarette (vaping) dependence among young people. In this prospective cohort study, we aimed to identify the different predictors of vaping dependence over 3 months among adolescents who were baseline daily and non-daily vapers. We recruited ever-vaping Canadian residents aged 16-25 years on social media platforms and asked them to complete a baseline survey in November 2020. A validated vaping dependence score (0-23) summing up their responses to nine questions was calculated at the 3-month follow-up survey. Separate lasso regression models were developed to identify predictors of higher 3-month vaping dependence score among baseline daily and non-daily vapers. Of the 1172 participants, 643 (54.9%) were daily vapers with a mean age of 19.6 ± 2.6 years and 76.4% (n = 895) of them being female. The two models achieved adequate predictive performance. Place of last vape purchase, number of days a pod lasts, and the frequency of nicotine-containing vaping were the most important predictors for dependence among daily vapers, while race, sexual orientation and reporting treatment for heart disease were the most important predictors in non-daily vapers. These findings have implications for vaping control policies that target adolescents at different stages of vape use.

Co-Use, Simultaneous Use, and Mixing of Cannabis and Tobacco: A Cross-National Comparison of Canada and the US by Cannabis Administration Type.

INTRODUCTION: Increasing cannabis legalization raises concerns that the use of tobacco, frequently used with cannabis, will also increase. This study investigated the association between the legal status of cannabis in places of residence and the prevalence of cannabis and tobacco co-use, simultaneous use, and mixing by comparing the prevalence among adults in Canada (prior to cannabis legalization) vs. adults in US states that had legalized recreational cannabis vs. US states that had not as of September 2018. METHODS: Data were drawn from the 2018 International Cannabis Policy Study, conducted with respondents aged 16-65 in Canada and the US recruited from nonprobability consumer panels. Differences in the prevalence of co-use, simultaneous use, and mixing between tobacco and different cannabis products were examined using logistic regression models by legal status of place of residence among past-12-month cannabis consumers (N = 6744). RESULTS: Co-use and simultaneous use in the past 12 months were most common among respondents in US legal states. Among cannabis consumers, co-use and simultaneous use were less common in US legal states, while mixing was less frequent in US states with both legal and illegal cannabis compared to Canada. Use of edibles was associated with lower odds of all three outcomes, while smoking dried herb or hash was associated with higher odds. CONCLUSIONS: The proportion of cannabis consumers who used tobacco was lower in legal jurisdictions despite higher prevalence of cannabis use. Edible use was inversely associated with co-use, suggesting that edible use does not appear to be associated with increased tobacco use.

Smoking, e-cigarettes and the effect on respiratory symptoms among a population sample of youth: Retrospective cohort study.

INTRODUCTION: E-cigarettes have been steadily increasing in popularity, both as cessation methods for smoking and for recreational and social reasons. This increase in vaping may pose cardiovascular and respiratory risks. We aimed to assess respiratory symptoms in youth users of e-cigarettes and cigarettes. METHODS: A retrospective survey design was utilized to assess Canadian youth aged 16-25 years. Participants were recruited from the Ontario Tobacco Research Unit Youth and Young Adult Research Registration Panel November 2020 to March 2021. A total of 3082 subjects completed the baseline survey. Of these, 2660 individuals who did not have asthma were included in the analysis. The exposure of interest was pack-equivalent years, a novel measure of vaping exposure equivalent conceptually to cigarette pack years incorporating number of puffs per day, number of days vaped per month, and number of years vaped. Respiratory symptoms were measured using the five-item Canadian Lung Health Test. Poisson regression analyses were performed while adjusting for demographic confounders, stratified by smoking status. A non-stratified model tested the interaction of status and vaping dose and the effect of vaping device used was assessed among ever vapers. Analyses controlled for demographic characteristics, use of cannabis and alcohol, and survey date. RESULTS: Each additional puff year increased the rate ratio (RR) of respiratory symptoms by a factor of 11.36 (95% CI: 4.61-28.00; p<0.001) for never smokers, but among current daily smokers higher pack-equivalent years were not associated with more respiratory symptoms (RR=0.83; 95% CI: 0.23-3.11). Among current vapers, those using pod-style devices were more likely to have more respiratory symptoms (RR=1.25; 95% CI: 1.08-1.45) after adjusting for dose. CONCLUSIONS: Vaping is associated with an increased risk of reporting respiratory symptoms among never smoking youth and non-daily ever cigarette smokers. Use of e-cigarettes among non-smokers should be discouraged.

The Compassion Club: A New Proposal for Transformation of Tobacco Retail.

INTRODUCTION: One major assumption in the current tobacco industry is the distribution of tobacco products through a system of commercial for-profit retail. However, other models of distribution that do not rely on this mechanism exist. AIMS AND METHODS: In this review, we examine the potential of a nonprofit Compassion Club model and discuss how the current existence of independent vape stores might provide the infrastructure to allow the transformation of tobacco distribution. RESULTS: Compassion Clubs exist internationally with different levels of regulation and legality and have generally been focused on the distribution of illegal drugs or hard-to-access pharmaceuticals. They provide access to drugs for existing users, limit access by novices, limit negative impacts from illicit markets, and provide social support focused on reducing harms associated with drug use. CONCLUSIONS: With decreasing prevalence of tobacco use in many countries and growing interest in a tobacco endgame, a Compassion Club model of distribution could help transition tobacco away from the model of commercial widely available distribution. More work is needed to develop the regulations and policies that might guide a compassion club model. IMPLICATIONS: Compassion clubs are a model for the distribution of psychoactive substances that are focused on harm reduction and social support rather than profit. There has been little discussion about the possibility that this promising model could be applied to help transform the tobacco industry. Many independent vape stores already demonstrate aspects of the compassion club model that could be used to support a transition.

Supporting Youth Vaping Cessation With the Crush the Crave Smartphone App: Protocol for a Randomized Controlled Trial.

BACKGROUND: The use of e-cigarettes, or vaping, has increased exponentially in the past decade, particularly among youth. Emerging evidence indicates growing nicotine dependence among youth, revealing historically higher rates of dependence among current e-cigarette users compared to rates seen in earlier research. Despite the urgent need for youth vaping cessation interventions, there is limited knowledge about the process of vaping cessation, and few evidence-based interventions are available to young people seeking support. A notable literature review on vaping cessation resources for young people recommended technology-based interventions, such as smartphone apps and SMS text messaging services, as a promising area of vaping cessation research and intervention development. OBJECTIVE: The primary aim of our study is to determine the effectiveness of the Crush the Crave app in supporting vaping cessation among youth recruited to the intervention arm via comparison with an assessment-only control group. The primary hypothesis is that participants in the intervention group-those using Crush the Crave-will be more likely to be abstinent at the 6-month follow-up point than participants in the assessment-only control arm. METHODS: A 2-arm, single-blind, parallel randomized controlled trial will be conducted over 12 months. Study invitations will be sent to 600 youth (age: 16-18 years) and young adult (age: 19-29 years) e-cigarette users and randomized between an intervention arm, which will be using Crush the Crave (n=300), and an assessment-only control arm (n=300) in a 1:1 ratio. The primary hypothesis is that participants in the intervention group-those using Crush the Crave-will be more likely to be abstinent at the 6-month follow-up point. RESULTS: Study recruitment began on March 4, 2022. Recruitment is anticipated to be completed in December 2022. CONCLUSIONS: This protocol describes one of the first-ever randomized controlled trial studies to evaluate the effectiveness of an app-based intervention for supporting vaping cessation among youth aged 16 to 18 years and young adults aged 19 to 29 years. The findings from our trial will help increase our understanding of the process of vaping cessation among youth and provide evidence on the effectiveness of an app-based intervention in helping young people quit vaping. The trial results will also have implications in the development of current and future approaches to youth vaping cessation. TRIAL REGISTRATION: OSF Registries osf.io/hmd87; https://doi.org/10.17605/OSF.IO/HMD87. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/42956.

Return on investment of Canadian tobacco control policies implemented between 2001 and 2016.

OBJECTIVES: To determine the return on investment (ROI) associated with tobacco control policies implemented between 2001 and 2016 in Canada. METHODS: Canadian expenditures on tobacco policies were collected from government sources. The economic benefits considered in our analyses (decrease in healthcare costs, productivity costs and monetised life years lost, as well as tax revenues) were based on the changes in smoking prevalence and attributable deaths derived from the SimSmoke simulation model for the period 2001-2016. The net economic benefit (monetised benefits minus expenditures) and ROI associated with these policies were determined from the government and societal perspectives. Sensitivity analyses were conducted to check the robustness of the result. Costs were expressed in 2019 Canadian dollars. RESULTS: The total of provincial and federal expenditures associated with the implementation of tobacco control policies in Canada from 2001 through 2016 was estimated at $2.4 billion. Total economic benefits from these policies during that time were calculated at $49.2 billion from the government perspective and at $54.2 billion from the societal perspective. The corresponding ROIs were $19.8 and $21.9 for every dollar invested. Sensitivity analyses yielded ROI values ranging from $16.3 to $28.3 for every dollar invested depending on the analyses and perspective. CONCLUSIONS: This analysis has found that the costs to implement the Canadian tobacco policies between 2001 and 2016 were far outweighed by the monetised value associated with the benefits of these policies, making a powerful case for the investment in tobacco control policies.

Machine learning applications in tobacco research: a scoping review.

OBJECTIVE: Identify and review the body of tobacco research literature that self-identified as using machine learning (ML) in the analysis. DATA SOURCES: MEDLINE, EMABSE, PubMed, CINAHL Plus, APA PsycINFO and IEEE Xplore databases were searched up to September 2020. Studies were restricted to peer-reviewed, English-language journal articles, dissertations and conference papers comprising an empirical analysis where ML was identified to be the method used to examine human experience of tobacco. Studies of genomics and diagnostic imaging were excluded. STUDY SELECTION: Two reviewers independently screened the titles and abstracts. The reference list of articles was also searched. In an iterative process, eligible studies were classified into domains based on their objectives and types of data used in the analysis. DATA EXTRACTION: Using data charting forms, two reviewers independently extracted data from all studies. A narrative synthesis method was used to describe findings from each domain such as study design, objective, ML classes/algorithms, knowledge users and the presence of a data sharing statement. Trends of publication were visually depicted. DATA SYNTHESIS: 74 studies were grouped into four domains: ML-powered technology to assist smoking cessation (n=22); content analysis of tobacco on social media (n=32); smoker status classification from narrative clinical texts (n=6) and tobacco-related outcome prediction using administrative, survey or clinical trial data (n=14). Implications of these studies and future directions for ML researchers in tobacco control were discussed. CONCLUSIONS: ML represents a powerful tool that could advance the research and policy decision-making of tobacco control. Further opportunities should be explored.