Does cannabis use moderate smoking cessation outcomes in treatment-seeking tobacco smokers? Analysis from a large multi-center trial

Cannabis Use and Subsequent Cigarette Discontinuation Among U.S. Adults in the Population Assessment of Tobacco and Health Study, Waves 1-5

INTRODUCTION

This study examined the association between the current co-use of cannabis and cigarettes in the past 30 days and subsequent cigarette discontinuation (past 30-day point-prevalence abstinence) among U.S. adults with established cigarette use in the Population Assessment of Tobacco and Health (PATH) Study. Additionally, we investigated the impact of co-use on the subsequent discontinuation of all combustible tobacco products.

AIMS AND METHODS

A total of 26 381 observations contributed by 8218 adults with established cigarette use (ie, smoked ≥100 cigarettes in their lifetime, and currently smoking cigarettes every day or some days) from waves 1-5 of the PATH Study were included in the analysis. Weighted generalized estimating equations (GEE) models were used to evaluate the association between current co-use at baseline (waves 1-4) with the outcomes assessed at the subsequent wave (cigarette and combustible tobacco discontinuation at waves 2-5). Final models included: Demographic characteristics (age, sex, race and ethnicity, and educational attainment), behavior characteristics (intention to quit, internalizing symptoms, externalizing symptoms, and substance use problems), and wave-pair.

RESULTS

Over one-third (35.91%) of the adults currently smoking cigarettes self-reported co-use during the study period. Cannabis use among adults with established cigarette use increased over time. Co-use was associated with decreased odds of cigarette smoking discontinuation at follow-up, after adjusting for covariates (aOR: 0.81; 95% CI: 0.72, 0.93; p = .0018). Similar effect sizes were observed for the discontinuation of all combustible tobacco products (aOR: 0.75; 95% CI: 0.65, 0.86; p < .0001).

CONCLUSIONS

Cannabis use among adults with established cigarette use was inversely related to subsequent cigarette discontinuation, suggesting that co-use may reduce the likelihood of successful tobacco cessation.

IMPLICATIONS

Findings demonstrate that cannabis use may lead to lower odds of discontinuation among adults with established cigarette use; therefore, individuals who co-use cigarettes and cannabis may need additional tobacco cessation support. Notably, this study observed an increase in the co-use of cigarettes and cannabis, emphasizing the need for researchers and public health programs to shift their focus toward understanding and addressing concurrent substance use among adults who smoke cigarettes.

Tobacco Quitline Callers Who Use Cannabis and Their Likelihood of Quitting Cigarette Smoking

INTRODUCTION

Cigarette smoking continues to decline in the U.S., but cannabis use is increasing. Many people who smoke cigarettes also use cannabis. This study examines the characteristics of persons who co-use and those who do not co-use and the likelihood of quitting cigarettes for callers to Kick It California, a large state tobacco quitline.

METHODS

Data were examined from Kick It California callers from January 2020 through December 2023 (N=45,151), including those from a subgroup randomly sampled and reached for evaluation at 7 months after quitline enrollment (n=3,545). The rate of cigarette smoking cessation at 7 months after enrollment for people who co-use cannabis was compared with that for people who do not. Analyses started in 2023 and concluded in January 2024.

RESULTS

More than a quarter (27.2%) of Kick It California callers co-used cannabis. They were more likely to be male, to be younger, and to have a mental health condition than those who did not. Those who co-use cannabis and those who do not have similar rates of receiving quitline counseling or using Food and Drug Administration-approved cessation aids. Controlled for effects of personal characteristics and use of smoking-cessation services, people who co-use cannabis were less likely to quit cigarette smoking 7 months after enrollment (23.2% vs 28.9%; p<0.001). Among those who co-use, 42.9% intended to quit using cannabis in the next 30 days.

CONCLUSIONS

A substantial percentage of tobacco quitline callers use cannabis. Those who do co-use quit cigarette smoking at a lower rate than those who do not. Over 40% of people who co-use reported intention to quit cannabis, making tobacco quitlines a rich environment to learn about people who co-use and develop strategies for intervention.

Do Determinants of Smoking Cessation and Relapse Differ between Men and Women? Data from a French National Study

Introduction: There is limited understanding of different predictors of smoking cessation success (SCS) among women and men, despite well-documented differences in smoking behavior.Methods: Using data from DePICT (Description des Perceptions, Images, et Comportements liés au Tabagisme), a national survey of French adults which recruited 2377 regular and former smokers we investigated whether major determinants of SCS differed by sex. Factors associated with unsuccessful vs. No successful quit attempt; vs. SCS were studied using multivariate multinomial logistic regression analyses stratified by sex.Results: Women and men share some determinants of SCS including no cannabis use, living in a nonsmoker household and importance giving to being a nonsmoker. However, no e-cigarette use, low-to-moderate alcohol consumption, early smoking initiation, and higher education were associated with SCS only among women. No use of nicotine replacement, having family members who smoke, family opinion on smoking and current employment, were associated with SCS only among men. Neutral or negative friends' opinion on smoking or living with a smoker were associated with unsuccessful smoking attempts among men.Conclusions: Our results show differences between determinants of SCS according to sex, which highlights the importance of developing tailored interventions that account for sex/gender differences in smoking cessation.

Co-use of cigarettes and cannabis among people with HIV: Results from a randomized controlled smoking cessation trial

Significance

People with HIV (PWH) who smoke cigarettes have lower cessation rates than the general population. This study investigated whether changes in cannabis use frequency impedes cigarette cessation among PWH who are motivated to quit.

Methods

Between 2016-2020, PWH who smoked cigarettes were enrolled in a randomized controlled trial for cigarette cessation. Analyses were limited to PWH who reported on their past 30-day (P30D) cannabis use during four study visits (baseline, 1-month, 3-month, and 6-month) (N=374). Descriptive statistics and multivariable logistic regression were used to evaluate changes in cannabis use frequency from baseline to 6 months and associations with cigarette abstinence at 6 months among PWH who reported no use during all four visits (n=176), as well as those who reported use during at least one visit and who increased (n=39), decreased (n=78), or had no change (n=81) in use frequency.

Results

Among those who reported cannabis use during at least one visit (n=198), at baseline, 18.2% reported no use. At 6 months, 34.3% reported no use. Controlling for covariates, increased cannabis use frequency from baseline was associated with reduced odds of cigarette abstinence at 6 months versus decreased use frequency (aOR=0.22, 95% CI=0.03, 0.90) or no use at either time-point (aOR=0.25, 95% CI=0.04, 0.93).

Conclusions

Increased cannabis use over 6 months was associated with reduced odds of cigarette smoking abstinence among PWH who were motivated to quit. Additional factors that influence cannabis use and cigarette cessation simultaneously are in need of further study.

Daily Cannabis Use Is a Barrier to Tobacco Cessation Among Tobacco Quitline Callers at 7-Month Follow-up

INTRODUCTION

Cannabis use is increasing among cigarette smokers in the United States. Prior studies suggest that cannabis use may be a barrier to smoking cessation. Yet, the extent to which this is the case among adults seeking to quit tobacco use remains unclear. Tobacco quitlines are the most common provider of no-cost treatment for adults who use smoke in the United States. This study investigated the association between cannabis use and smoking cessation outcomes among quitline callers.

AIMS AND METHODS

Participants included callers to the New York State Smokers' Quitline, who were seeking to quit smoking cigarettes and were contacted for outcome assessment 7 months after intake. Thirty-day point prevalence abstinence rates were calculated and compared among cannabis use groups, based on frequency of past-30-day cannabis use at baseline (none: 0 days, occasional: 1-9 days, regular: 10-19 days, and daily: 20-30 days).

RESULTS

Approximately 8.3% (n = 283) of participants (n = 3396) reported past-30-day cannabis use at baseline. Callers with daily cannabis use (20-30 days per month) had significantly lower odds of 30-day abstinence, relative to those who did not use cannabis (odds ratio = 0.5; 95% confidence interval [0.3, 0.9]).

CONCLUSIONS

Daily cannabis use appears to be associated with poorer smoking cessation treatment outcomes among adults seeking to quit smoking cigarettes via a quitline. Because quitlines are among the most accessible, affordable, and frequently utilized community-based treatments available in the United States, and the prevalence of cannabis use is increasing among cigarette smokers, detailed inquiry into cannabis use might enhance cigarette smoking cessation outcomes.

IMPLICATIONS

Quitlines are free of cost and accessible to millions of smokers in the United States. The current study found an inverse relationship between daily cannabis use at baseline and 30-day abstinence from cigarette smoking at 7-month follow-up among New York State Smokers' Quitline callers. Findings suggest that daily cannabis use may be a barrier to smoking cessation and sustained abstinence among those seeking help to stop smoking cigarettes.

Age-period-cohort analysis of trends in tobacco smoking, cannabis use, and their co-use in the Australian population

BACKGROUND AND AIM

The prevalence of tobacco smoking has declined in most high-income countries, while cannabis use has been rising. Moreover, cannabis use has been found to have increased among cigarette smokers in recent years in jurisdictions where it has been either decriminalized or legalized. This study measured trends in cannabis, tobacco and the co-use of cannabis and tobacco in Australia.

DESIGN

Age-period-cohort analysis.

SETTING AND PARTICIPANTS

Participants were n = 143 344 individuals aged 18-80 years who participated in Australia's National Drug Strategy Household Surveys (NDSHS) between 2001 and 2019.

MEASUREMENTS

Regular (weekly/more frequently): (1) tobacco smoking only, (2) cannabis use only and (3) the co-use of cannabis and tobacco.

FINDINGS

Prevalence of only smoking tobacco decreased in all age groups (P < 0.001) and birth cohorts between 2001 and 2019, but the co-use of cannabis and tobacco did not. Younger cohorts were much less likely to co-use tobacco and cannabis (P = 0.02). Period trends showed that both cannabis use only and the co-use of cannabis and tobacco have increased since 2013.

CONCLUSION

There has been a consistent decrease in exclusive tobacco smoking across age, period and birth cohorts between 2001 and 2019 in Australia, although there is a recent increasing period trend in cannabis use with or without tobacco. The non-decreasing trend of co-use may reflect the strong tobacco control policies introduced over the period and changing attitudes towards cannabis use in Australia.

Association between Smoking Cannabis and Quitting Cigarettes in a Large American Cancer Society Cohort

BACKGROUND

Cannabis use is increasing, including among smokers, an at-risk population for cancer. Research is equivocal on whether using cannabis inhibits quitting cigarettes. The current longitudinal study investigated associations between smoking cannabis and subsequently quitting cigarettes.

METHODS

Participants were 4,535 adult cigarette smokers from a cohort enrolled in the American Cancer Society's Cancer Prevention Study-3 in 2009-2013. Cigarette quitting was assessed on a follow-up survey in 2015-2017, an average of 3.1 years later. Rates of quitting cigarettes at follow-up were examined by retrospectively assessed baseline cannabis smoking status (never, former, recent), and by frequency of cannabis smoking among recent cannabis smokers (low: ≤3 days/month; medium: 4-19 days/month; high: ≥20 days/month). Logistic regression models adjusted for sociodemographic factors, smoking- and health-related behaviors, and time between baseline and follow-up.

RESULTS

Adjusted cigarette quitting rates at follow-up did not differ significantly by baseline cannabis smoking status [never 36.2%, 95% confidence interval (CI), 34.5-37.8; former 34.1%, CI, 31.4-37.0; recent 33.6%, CI, 30.1-37.3], nor by frequency of cannabis smoking (low 31.4%, CI, 25.6-37.3; moderate 36.7%, CI, 30.7-42.3; high 34.4%, CI, 28.3-40.2) among recent baseline cannabis smokers. In cross-sectional analyses conducted at follow-up, the proportion of cigarette smokers intending to quit smoking cigarettes in the next 30 days did not differ by cannabis smoking status (P = 0.83).

CONCLUSIONS

Results do not support the hypothesis that cannabis smoking inhibits quitting cigarette smoking among adults.

IMPACT

Future longitudinal research should include follow-ups of >1 year, and assess effects of intensity/frequency of cannabis use and motivation to quit on smoking cessation.

Increasing cannabis use is associated with poorer cigarette smoking cessation outcomes: Findings from the ITC Four Country Smoking and Vaping Surveys, 2016-2018

INTRODUCTION

Concurrent use (co-use) of tobacco and cannabis may impede successful cigarette smoking cessation. This study examined whether changes in cannabis use frequency were associated with smoking cessation.

METHODS

Nationally representative samples of adult cigarette smokers from Canada (n=1455), the United States (n=892), England (n=1416), and Australia (n=717) were surveyed in 2016 and 2018. In each year, smokers reported how often they used cannabis in the previous 12 months. Reports were compared to determine whether cannabis use increased, remained unchanged, or decreased. Smoking cessation outcomes, measured in 2018, were (1) any attempt to quit in the previous year, (2) currently quit, and (3) currently quit for at least 6 months. Weighted multivariable logistic regression estimated the association between changes in cannabis use and cessation outcomes.

RESULTS

Cigarette smokers who increased their frequency of cannabis use were significantly less likely to be currently quit than non-cannabis using smokers (adjusted odds ratio (aOR) = 0.52, 95% CI: 0.31, 0.86); they were also less likely to have quit for at least 6 months (aOR = 0.30; 95% CI: 0.15, 0.62).

CONCLUSIONS

Smokers who increase their frequency of cannabis use have poorer smoking cessation outcomes compared to non-cannabis using smokers. It will be important to monitor the impact of cannabis legalization on patterns of cannabis use, and whether this influences cigarette smoking cessation rates.

Self-reported reductions in tobacco and nicotine use following medical cannabis initiation: Results from a cross-sectional survey of authorized medical cannabis patients in Canada

BACKGROUND

Despite decades of campaigns aimed at reducing tobacco/nicotine (T/N) use and the development of many different T/N reduction and cessation strategies, the impacts on international public health remain significant. Some studies have found an association between medical and non-medical cannabis use and T/N use, although the evidence on whether cannabis/cannabinoids increase or decrease the odds of reducing or ceasing T/N use remain contradictory. This paper explores the self-reported use of cannabis and associated changes in T/N use among a Canadian medical cannabis patient population.

METHODS

This study examines the impact of medical cannabis on T/N use by comparing self-reported patterns of use before and after the initiation of medical cannabis. Participants completed an online cross-sectional survey examining demographics, patterns of medical cannabis use, and the impact of medical cannabis on the use of T/N and other substances. The survey also included novel measures examining whether patients intended to use medical cannabis to reduce T/N use or had experience with other pharmacological or psychobehavioral T/N cessation strategies. We conducted a series of descriptive analyses and univariate and multivariate logistic regressions to explore the potential association between primary variables of interest and T/N reduction and cessation.

RESULTS

In total, the study recruited 2102 individuals, of whom 650 were current or former T/N users. Following initiation of medical cannabis use 320 (49%) T/N users self-reported reductions in use, with 160 (24.6%) reporting no T/N use in the 30 days prior to the survey. Odds of T/N cessation were greater among those who were age 55 or older (Adjusted Odds Ratio [AOR] = 2.56, 95% Confidence Interval [CI] 1.53-4.26), or those who reported >25 T/N uses per day in the pre-period (AOR = 2.11, 95% CI 1.14-3.92). Specific intent to use medical cannabis to quit resulted in significantly greater odds of reducing T/N use (AOR = 2.79, 95% CI 1.49-5.22); however, involvement with traditional T/N cessation treatments (pharmacological or psychobehavioral) was negatively associated with T/N cessation (AOR 0.39, 95% CI 0.18-0.86).

CONCLUSIONS

Results from this retrospective survey of medical cannabis users suggest that initiation of medical cannabis use was associated with self-reported reductions and/or cessation of T/N use in nearly half of study participants. In light of the significant morbidity, mortality, and health care costs related to T/N dependence, future research should further evaluate the potential of cannabis-based treatments to support efforts to reduce or cease T/N use.

Addressing concerns about smoking cessation and mental health: theoretical review and practical guide for healthcare professionals

Smoking rates in people with depression and anxiety are twice as high as in the general population, even though people with depression and anxiety are motivated to stop smoking. Most healthcare professionals are aware that stopping smoking is one of the greatest changes that people can make to improve their health. However, smoking cessation can be a difficult topic to raise. Evidence suggests that smoking may cause some mental health problems, and that the tobacco withdrawal cycle partly contributes to worse mental health. By stopping smoking, a person's mental health may improve, and the size of this improvement might be equal to taking anti-depressants. In this theoretical review and practical guide we outline ways in which healthcare professionals can raise the topic of smoking compassionately and respectfully to encourage smoking cessation. We draw on evidence-based methods like cognitive behavioural therapy, and outline approaches that healthcare professionals can use to integrate these methods into routine care.

Treatment Implications Associated with Cannabis and Tobacco Co-Use

PURPOSE OF THE REVIEW

The goal of this article is to summarize the treatment-focused literature on cannabis and tobacco co-use and the treatment implications of co-use. This review will focus on: 1) the impact of co-use on cessation outcomes, 2) compensatory use/substitution of the non-treated substance among co-users, and 3) treatment interventions to address co-use. This article will highlight the limitations to co-use captured in the literature and offer considerations and directives for co-use research and treatment moving forward.

RECENT FINDINGS

The degree to which co-use affects cessation for a single, targeted substance remains in question, as the literature is largely mixed. Cannabis treatment trials are better equipped to answer these questions given that they do not typically exclude tobacco users. While the relationship between tobacco use and poorer cannabis outcomes appears to have some evidence, the reverse relationship (cannabis use affecting tobacco outcomes) is not consistently supported.

SUMMARY

The co-use of cannabis and tobacco and its impact on single substance cessation and/or compensatory substance use during cessation is generally overlooked in treatment trials, while interventions to address both substances are rare. Capturing co-use adds burden for researchers, clinicians, and participants, but is warranted given the prevalence of co-use and a rapidly changing cannabis and tobacco regulatory environment, which may further complicate co-occurring substance use. Co-users are a heterogeneous population; trials focused on co-users, in addition to better data capture and consistent terminology, will aid in an understanding of nuanced patterns of co-use critical to inform treatment interventions.

Cannabis and Alcohol Co-Use in a Smoking Cessation Pharmacotherapy Trial for Adolescents and Emerging Adults

INTRODUCTION

The co-use of cannabis and alcohol among tobacco-using youth is common. Alcohol co-use is associated with worse tobacco cessation outcomes, but results are mixed regarding the impact of cannabis on tobacco outcomes and if co-use leads to increased use of non-treated substances. This secondary analysis from a youth smoking cessation trial aimed to (1) evaluate the impact of cannabis or alcohol co-use on smoking cessation, (2) examine changes in co-use during the trial, and (3) explore secondary effects of varenicline on co-use.

METHODS

The parent study was a 12-week, randomized clinical trial of varenicline for smoking cessation among youth (ages 14-21, N = 157; Mage = 19, 40% female; 76% White). Daily cigarette, cannabis, and alcohol use data were collected via daily diaries during treatment and Timeline Follow-back for 14 weeks post-treatment.

RESULTS

Baseline cannabis co-users (68%) had double the odds of continued cigarette smoking throughout the trial compared with noncannabis users, which was pronounced in males and frequent cannabis users. Continued smoking during treatment was associated with higher probability of concurrent cannabis use. Baseline alcohol co-users (80%) did not have worse smoking outcomes compared with nonalcohol users, but continued smoking was associated with higher probability of concurrent drinking. Varenicline did not affect co-use.

CONCLUSIONS

Inconsistent with prior literature, results showed that alcohol co-users did not differ in smoking cessation, whereas cannabis co-users had poorer cessation outcomes. Youth tobacco treatment would benefit from added focus on substance co-use, particularly cannabis, but may need to be tailored appropriately to promote cessation.

IMPLICATIONS

Among youth cigarette smokers enrolled in a pharmacotherapy evaluation clinical trial, alcohol and/or cannabis co-use was prevalent. The co-use of cannabis affected smoking cessation outcomes, but more so for males and frequent cannabis users, whereas alcohol co-use did not affect smoking cessation. Reductions in smoking were accompanied by concurrent reductions in alcohol or cannabis use. Substance co-use does not appear to affect all youth smokers in the same manner and treatment strategies may need to be tailored appropriately for those with lower odds of smoking cessation.

Prospective and Daily Effects of Cannabis Use on Smoking Outcomes During a Self-Guided Quit Attempt

INTRODUCTION

Past research suggests that cannabis use is a risk factor for relapse in people trying to quit smoking. Most people attempt to quit smoking without any assistance (ie, self-guided quitters), yet no one has examined the association between cannabis use and relapse among self-guided quitters. The current study examines how cannabis use might contribute to poorer smoking outcomes in a sample of self-guided quitters.

AIMS AND METHODS

Data were taken from a study of unaided smoking cessation in 62 single-smoker couples. Quitters and their Partners completed baseline questionnaires and a 21-day ecological momentary assessment. This article examines Quitters' and Partners' past-year cannabis use reported at baseline and daily cannabis use during the ecological momentary assessment as predictors of prospective and daily smoking outcomes.

RESULTS

We found very little evidence that past-year cannabis use was associated with poorer smoking outcomes. However, Quitters reported greater smoking on days when they or their Partners reported cannabis use.

CONCLUSIONS

This study produced evidence to support daily Quitter and Partner cannabis use as a risk factor for poor smoking outcomes. Smoking cessation programs might benefit from targeting cannabis use as well as taking a couples-oriented approach to treatment.

IMPLICATIONS

This article examined how cannabis use impacts smoking outcomes in a sample of self-guided quitters using prospective and daily diary analyses. We found very little evidence that past-year cannabis use was associated with poorer smoking outcomes. However, Quitters reported greater smoking on days when they or their Partners reported cannabis use. Findings suggest that smoking cessation programs might benefit from targeting cannabis use, as well as taking a couples-oriented approach to treatment.

A systematic review and Bayesian meta-analysis of interventions which target or assess co-use of tobacco and cannabis in single- or multi-substance interventions

BACKGROUND AND AIMS

Tobacco and cannabis are commonly co-used, and evidence for the influence of co-use on quit outcomes for either substance is mixed. We sought to determine the efficacy of tobacco and/or cannabis use interventions delivered to co-users on cannabis and tobacco use outcomes.

METHOD

Systematic review with meta-analysis and narrative review, using five databases and author requests for co-use data. Controlled and uncontrolled intervention studies focusing on treatment of tobacco and/or cannabis use assessing use of both pre- and post-intervention were included. Prevention interventions were excluded. Bayesian meta-analysis was used across four outcome measures: risk ratio for tobacco and cannabis cessation post-intervention separately; standardized mean change for tobacco and cannabis reduction post-intervention separately. Narrative reporting of the same outcome measures in non-randomized clinical trials (non-RCTs) and quality assessment of all included studies were conducted.

RESULTS

Twenty studies (12 RCTs and eight uncontrolled) were included. Bayesian meta-analysis with informative priors based on existing data of 11 RCTs (six single-substance, five multi-substance interventions) delivered to co-users (n = up to 1117) showed weak evidence for an effect on cannabis cessation [risk ratio (RR) = 1.48, credibility interval (CrI) = 0.92, 2.49, eight studies] and no clear effect on tobacco cessation (RR = 1.10, CrI = 0.68, 1.87, nine studies). Subgroup analysis suggested that multi-substance interventions might be more effective than cannabis-targeted interventions on cannabis cessation (RR = 2.19, CrI = 1.10, 4.36 versus RR = 1.39, CrI = 0.75, 2.74). A significant intervention effect was observed on cannabis reduction (RR = 0.25, CrI = 0.03, 0.45, nine studies) but not on tobacco reduction (RR = 0.06, CrI = -0.11, 0.23, nine studies). Quality of evidence was moderate, although measurement of co-use and cannabis use requires standardization. Uncontrolled studies targeting both cannabis and tobacco use indicated feasibility and acceptability.

CONCLUSIONS

Single and multi-substance interventions addressing tobacco and/or cannabis have not shown a clear effect on either tobacco or cannabis cessation and reduction among co-users. However, dual substance interventions targeting tobacco and cannabis appear feasible.

International differences in patterns of cannabis use among adult cigarette smokers: Findings from the 2018 ITC Four Country Smoking and Vaping Survey

BACKGROUND

Although evidence shows that co-use of cigarettes and cannabis is common, there is little research examining if co-use patterns vary depending on the regulatory environment for cannabis. This study examined patterns of co-use and perceptions of relative harm among cigarette smokers in four countries with different histories, and at different stages of cannabis legalization.

METHODS

Data are from the 2018 International Tobacco Control 4CV Survey and included 10035 adult cigarette smokers from Canada, United States (US), Australia, and England. At the time of the survey, Canada and the US had relatively more permissive cannabis regulations compared to Australia and England.

RESULTS

Among this sample of 10035 cigarette smokers, Canada had the highest rate of cannabis co-use in the last 12 months (36.3%), followed by the US (29.1%), England (21.6%), and Australia (21.4%). Among past 12 month co-users (n = 3134), the US (40.2%) and Canada (35.2%) had the highest rates of daily cannabis use, followed by smokers in England (26.3%) and Australia (21.7%); Australian co-users had the highest rate of infrequent (

CONCLUSION

Patterns of tobacco and cannabis co-use differed between countries. Smokers in Canada and the US had higher rates of co-use, daily cannabis use, dual-daily use of both cannabis and cigarettes, and were more likely to perceive smoked cannabis as less harmful than cigarettes compared to England and Australia. Further attention as to how varying cannabis regulations may impact co-use patterns is warranted.

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Key Words

• Cannabis
• Co-use
• Harm Perceptions
• Policy
• Regulation
• Tobacco cigarettes

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MESH Headings Collapse

Grants

• P01 CA200512 NCI NIH HHS

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Affiliation(s)

Shannon Gravely Department of Psychology, University of Waterloo, Waterloo, Canada.
Pete Driezen Department of Psychology, University of Waterloo, Waterloo, Canada; School of Public Health and Health Systems, University of Waterloo, Waterloo, Canada
Danielle M Smith Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, United States
Ron Borland School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia; Cancer Council Victoria, Melbourne, VIC, Australia
Eric N Lindblom O'Neill Institute for National & Global Health Law, Georgetown University Law Center, Washington, DC United States
David Hammond School of Public Health and Health Systems, University of Waterloo, Waterloo, Canada
Ann McNeill King's College London, Addictions Department, Institute of Psychiatry, Psychology & Neuroscience, London, United Kingdom; UK Centre for Tobacco & Alcohol Studies, Nottingham, United Kingdom
Andrew Hyland Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, United States
K Michael Cummings Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, Charleston, United States; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States
Gary Chan Centre for Youth Substance Abuse Research, The University of Queensland, Brisbane, QLD, Australia
Mary E Thompson Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Canada
Christian Boudreau Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Canada
Nadia Martin Department of Psychology, University of Waterloo, Waterloo, Canada
Janine Ouimet Department of Psychology, University of Waterloo, Waterloo, Canada
Ruth Loewen Department of Psychology, University of Waterloo, Waterloo, Canada
Anne C K Quah Department of Psychology, University of Waterloo, Waterloo, Canada
Maciej L Goniewicz Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, United States
James F Thrasher Department of Health Promotion, Education & Behavior, Arnold School of Public Health, University of South Carolina, Columbia, United States; Tobacco Research Department, Center for Population Health Research, National Institute of Public Health, Cuernavaca, Mexico
Geoffrey T Fong Department of Psychology, University of Waterloo, Waterloo, Canada; School of Public Health and Health Systems, University of Waterloo, Waterloo, Canada; Ontario Institute for Cancer Research, Toronto, Canada

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Is cannabis use associated with tobacco cessation outcome? An observational cohort study in primary care

BACKGROUND

Some studies suggest cannabis use negatively affects tobacco cessation outcomes, but findings have been mixed. We examined whether cannabis use was associated with tobacco cessation outcomes in a real-world primary care setting.

METHODS

The analytic dataset consisted of 35,246 patients who enrolled between 2014 and 2016 in a primary care-based smoking cessation program in Ontario, Canada. Past 30-day cannabis use, for recreational or medical purposes, was self-reported at enrollment. Thirty-day point prevalence tobacco smoking abstinence was self-reported via online or telephone survey at 6 months post-enrollment.

RESULTS

Thirty days prior to enrollment, 79.9 % of patients had not used cannabis, 16.3 % used cannabis for recreational purposes only, and 3.8 % used cannabis for medical purposes. Unadjusted and adjusted odds of tobacco cessation at 6 months were reduced for patients using cannabis compared to non-users (ORs = 0.76-0.86, ps<0.05). When cannabis use was categorized by purpose, both unadjusted and adjusted odds of cessation were significantly lower for recreational users (ORs = 0.77-0.84, ps<0.05). Medical users had decreased odds of cessation in unadjusted analysis (OR = 0.74, 95 % CI = 0.61-0.89, p = 0.001), but not after adjustment for potential confounders. However, post-estimation contrasts did not indicate a significant difference between the effect of recreational and medical cannabis use.

CONCLUSIONS

In a large real-world sample of patients seeking smoking cessation treatment, concurrent cannabis use was associated with decreased success with quitting smoking. Recreational cannabis use was consistently related to poorer cessation outcomes, but medical use was not. Additional research is needed to inform treatment strategies for this growing sub-population of smokers.

Is Cannabis Use Associated With Increased Risk of Cigarette Smoking Initiation, Persistence, and Relapse? Longitudinal Data From a Representative Sample of US Adults

OBJECTIVE

The current study prospectively investigated the relationship between cannabis use and cigarette smoking initiation, persistence, and relapse during a 3-year period among adults in the United States.

METHODS

Analyses included respondents who completed Waves 1 (2001-2002) and 2 (2004-2005) of the National Epidemiologic Survey on Alcohol and Related Conditions and responded to questions about cannabis use and smoking status (n = 34,639). Multivariable logistic regression models were used to calculate the odds of cigarette use at Wave 2 among Wave 1 daily smokers, nondaily smokers, former smokers, and nonsmokers by Wave 1 cannabis use.

RESULTS

In unadjusted analyses, Wave 1 cannabis use was associated with increased odds of Wave 2 daily and nondaily smoking for Wave 1 nonsmokers (daily OR = 2.90; 95% CI, 2.10-4.00; nondaily OR = 4.45; 95% CI, 3.97-5.00) and Wave 2 relapse to daily and nondaily smoking for Wave 1 former smokers (daily OR = 4.18, 95% CI, 3.01-5.81; nondaily OR = 5.24; 95% CI, 3.74-7.34). Wave 1 cannabis use was associated with decreased odds of Wave 2 smoking cessation for Wave 1 daily cigarette smokers (OR = 0.57; 95% CI, 0.51-0.64). The associations remained significant for daily smoking initiation (OR = 1.43; 95% CI, 1.06-1.93), daily smoking relapse (OR = 1.47; 95% CI, 1.00-2.16), and smoking cessation (OR = 0.77; 95% CI, 0.69-0.87) after adjusting for demographics and psychiatric disorders. Associations remained significant for nondaily smoking initiation (OR = 1.85; 95% CI, 1.59-2.16) and nondaily smoking relapse (OR = 1.63; 95% CI, 1.05-2.54) after adjusting for these covariates as well as for alcohol and substance use disorders.

CONCLUSIONS

Cannabis use was associated with increased initiation of, persistence of, and relapse to cigarette smoking. Additional attention to cannabis use in tobacco control efforts and in clinical settings aimed at reducing cigarette smoking and smoking-related negative consequences may be warranted.

Tobacco use during cannabis cessation: Use patterns and impact on abstinence in a National Drug Abuse Treatment Clinical Trials Network study

BACKGROUND

It is common for cannabis users to also use tobacco. While data suggest that tobacco users have more difficulty achieving cannabis cessation, secondary analyses of clinical trial data sets may provide insight into the moderating variables contributing to this relationship, as well as changes in tobacco use during cannabis treatment. Those were the aims of this secondary analysis.

METHODS

The parent study was a multi-site trial of N-acetylcysteine for cannabis dependence conducted within the National Drug Abuse Treatment Clinical Trials Network. Participants were treatment-seeking adults (ages 18-50) who met criteria for cannabis dependence (N = 302). For cigarette smokers (n = 117), tobacco use was assessed via timeline follow-back and nicotine dependence was assessed via the Fagerström Test for Nicotine Dependence (FTND). Outcome measures included: 1) changes in tobacco use based on treatment assignment, nicotine dependence, and concurrent cannabis reduction/abstinence, and 2) independent associations between nicotine dependence and cannabis abstinence.

RESULTS

Cigarette smokers accounted for 39% of the sample (117/302), with a median FTND score of 3.0 (10-point scale). Among those with lower baseline nicotine dependence scores, cigarette smoking was reduced in the active treatment group compared to placebo. Those with moderate/high levels of nicotine dependence showed slight increases in smoking following active treatment. Nicotine dependence did not affect cannabis cessation.

CONCLUSIONS

Cigarette smoking during cannabis treatment was affected, but depended on baseline nicotine dependence severity, though dependence levels did not impact cannabis abstinence. Interventions that address both tobacco and cannabis are needed, especially due to an increasing prevalence of cannabis use.

Nicotine replacement therapy versus control for smoking cessation

BACKGROUND

Nicotine replacement therapy (NRT) aims to temporarily replace much of the nicotine from cigarettes to reduce motivation to smoke and nicotine withdrawal symptoms, thus easing the transition from cigarette smoking to complete abstinence.

OBJECTIVES

To determine the effectiveness and safety of nicotine replacement therapy (NRT), including gum, transdermal patch, intranasal spray and inhaled and oral preparations, for achieving long-term smoking cessation, compared to placebo or 'no NRT' interventions.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group trials register for papers mentioning 'NRT' or any type of nicotine replacement therapy in the title, abstract or keywords. Date of most recent search is July 2017.

SELECTION CRITERIA

Randomized trials in people motivated to quit which compared NRT to placebo or to no treatment. We excluded trials that did not report cessation rates, and those with follow-up of less than six months, except for those in pregnancy (where less than six months, these were excluded from the main analysis). We recorded adverse events from included and excluded studies that compared NRT with placebo. Studies comparing different types, durations, and doses of NRT, and studies comparing NRT to other pharmacotherapies, are covered in separate reviews.

DATA COLLECTION AND ANALYSIS

Screening, data extraction and 'Risk of bias' assessment followed standard Cochrane methods. The main outcome measure was abstinence from smoking after at least six months of follow-up. We used the most rigorous definition of abstinence for each trial, and biochemically validated rates if available. We calculated the risk ratio (RR) for each study. Where appropriate, we performed meta-analysis using a Mantel-Haenszel fixed-effect model.

MAIN RESULTS

We identified 136 studies; 133 with 64,640 participants contributed to the primary comparison between any type of NRT and a placebo or non-NRT control group. The majority of studies were conducted in adults and had similar numbers of men and women. People enrolled in the studies typically smoked at least 15 cigarettes a day at the start of the studies. We judged the evidence to be of high quality; we judged most studies to be at high or unclear risk of bias but restricting the analysis to only those studies at low risk of bias did not significantly alter the result. The RR of abstinence for any form of NRT relative to control was 1.55 (95% confidence interval (CI) 1.49 to 1.61). The pooled RRs for each type were 1.49 (95% CI 1.40 to 1.60, 56 trials, 22,581 participants) for nicotine gum; 1.64 (95% CI 1.53 to 1.75, 51 trials, 25,754 participants) for nicotine patch; 1.52 (95% CI 1.32 to 1.74, 8 trials, 4439 participants) for oral tablets/lozenges; 1.90 (95% CI 1.36 to 2.67, 4 trials, 976 participants) for nicotine inhalator; and 2.02 (95% CI 1.49 to 2.73, 4 trials, 887 participants) for nicotine nasal spray. The effects were largely independent of the definition of abstinence, the intensity of additional support provided or the setting in which the NRT was offered. A subset of six trials conducted in pregnant women found a statistically significant benefit of NRT on abstinence close to the time of delivery (RR 1.32, 95% CI 1.04 to 1.69; 2129 participants); in the four trials that followed up participants post-partum the result was no longer statistically significant (RR 1.29, 95% CI 0.90 to 1.86; 1675 participants). Adverse events from using NRT were related to the type of product, and include skin irritation from patches and irritation to the inside of the mouth from gum and tablets. Attempts to quantitatively synthesize the incidence of various adverse effects were hindered by extensive variation in reporting the nature, timing and duration of symptoms. The odds ratio (OR) of chest pains or palpitations for any form of NRT relative to control was 1.88 (95% CI 1.37 to 2.57, 15 included and excluded trials, 11,074 participants). However, chest pains and palpitations were rare in both groups and serious adverse events were extremely rare.

AUTHORS' CONCLUSIONS

There is high-quality evidence that all of the licensed forms of NRT (gum, transdermal patch, nasal spray, inhalator and sublingual tablets/lozenges) can help people who make a quit attempt to increase their chances of successfully stopping smoking. NRTs increase the rate of quitting by 50% to 60%, regardless of setting, and further research is very unlikely to change our confidence in the estimate of the effect. The relative effectiveness of NRT appears to be largely independent of the intensity of additional support provided to the individual. Provision of more intense levels of support, although beneficial in facilitating the likelihood of quitting, is not essential to the success of NRT. NRT often causes minor irritation of the site through which it is administered, and in rare cases can cause non-ischaemic chest pain and palpitations.

Commentary: Navigating the complexities of marijuana

Science needs to drive our thinking as we navigate a new legislative environment in which many Americans have access to marijuana for therapeutic or recreational use. With the responsibility to fund, conduct, and make use of the research on marijuana, and understand the impacts of new policies, comes the obligation of not thinking in simplistic, black-and-white terms about this substance. The drug's unique harms include neurodevelopmental impacts that may be long lasting or permanent, yet some evidence suggests the drug may benefit people with certain medical conditions (e.g., chronic pain). Marijuana use is also entangled with other substance use and should not be considered in isolation. Finally, policy options are not limited to the extremes of prohibition vs. full commercialization; a spectrum of intermediate options can and should be considered and evaluated as states create new policies around this drug.

Examining the effects of illicit drug use on tobacco cessation outcomes in the Helping HAND 2 randomized controlled trial

BACKGROUND

Individuals with substance use disorders (SUD) smoke at higher rates and have higher tobacco-related mortality than the general population. Despite having an interest in smoking cessation, smokers with SUDs may have greater difficulty quitting.

METHODS

Analysis of data from a RCT testing a post-discharge smoking cessation intervention for hospitalized cigarette smokers interested in quitting. Past 7day tobacco abstinence was self-reported at 1, 3, and 6 months and biochemically confirmed at 6 months post-discharge. Other drug use was assessed at baseline by self-report or a past-year discharge diagnosis of SUD. Multiple logistic regression compared tobacco cessation outcomes among participants with no recreational drug use (NDU; n=942) vs. marijuana only (MU; n=284) vs. other illicit drugs (IDU; n=131).

RESULTS

Groups differed at baseline on age, gender, race, education, other household smokers, alcohol use, and anxiety/depression (all p<0.05). Confirmed 6-month tobacco abstinence was lower among IDU than NDU participants (9% vs 18%, p=0.01; AOR=0.43, CI: 0.22-0.84) after adjustment for study arm, smoking characteristics, demographics, quality of life, alcohol use and MU. Confirmed 6-month abstinence did not differ significantly between MU vs. NDU participants (14% vs 18%, p>0.05; AOR=0.77, CI:0.51-1.14). Counseling and medication use did not differ significantly among groups at any follow-up.

CONCLUSIONS

Hospitalized smokers who planned to stop smoking after discharge and used cessation assistance were less successful if they had used illicit drugs in the past year, but not if they had only used marijuana. More intensive or tailored interventions may be required to address smoking in this population.