Trends in Daily Cannabis Use Among Cigarette Smokers: United States, 2002-2014

E-cigarette use among a national sample of adults receiving substance use treatment in the United States

BACKGROUND

Smoking among adults in substance use disorder (SUD) treatment programs is common with limited success in quitting. Given e-cigarettes' potential for smoking harm reduction, it is important to examine e-cigarette use among people in SUD treatment.

METHODS

We analyzed data from adults who have received SUD treatment in the past year, from the 2020-2021 National Survey on Drug Use and Health (N = 1,246). We delineated correlates of lifetime and current (past-month) use e-cigarette use.

RESULTS

Among adults receiving SUD treatment, an estimated 39.4 % (95 % CI: 34.1, 45.1) have used e-cigarettes in their lifetime and 19.5 % (95 % CI: 16.1, 23.6) of those currently vape. Among those reporting current vaping, an estimated 57.3 % (95 % CI: 44.9-68.8) currently smoke cigarettes and half (54.2 % [95 % CI: 41.1-66.7]) currently use cannabis. Compared to those who only received treatment for alcohol use disorder, those receiving treatment for drug use (aPR = 1.47, 95 % CI: 1.09-1.99) and alcohol and drug use (aPR = 1.60, 95 % CI: 1.16-2.22) had higher prevalence of lifetime e-cigarette use, and those reporting treatment for drug use only (aPR = 2.60, 95 % CI: 1.52-4.46) and alcohol and drug use (aPR = 2.82, 95 % CI: 1.63-4.87) also had higher prevalence of current e-cigarette use.

CONCLUSIONS

The prevalence of e-cigarette use was higher among those in treatment for both drug or alcohol and drugs only than those receiving treatment for only alcohol use. Smoking harm reduction interventions can potentially include e-cigarette among those receiving drug treatment. There is also a need to address challenges of dual e-cigarette and cigarette use, as well as dual e-cigarette use with cannabis.

Patterns of Cannabis Use among Women With HIV in the United States

Cannabis legalization in the United States changed cannabis product potency and consumption modalities. Women with HIV are an aging population with prevalent cannabis use twice that of national estimates. Because cannabis use may confer both health benefits and risks, it is important to understand cannabis use patterns among women with HIV. This analysis characterized prevalence, frequencies, and modes (smoking, vaping, eating) of cannabis use among 1,246 women with HIV in the Women's Interagency HIV Study over 18 months (2018-2019). We compared participant characteristics using chi-square tests and Wilcoxon rank-sum tests. We illustrated flow between cannabis use frequency categories with a Sankey diagram. Median participant age was 52 years (interquartile range: 46, 58). 65% of participants identified as Black/African American; 50% had annual household incomes <$12,000. The period prevalence was 27% for any cannabis use and 15% for daily or more use. 50% reported varying use frequencies. Among women using cannabis, 96% reported smoking, 30% consumed edibles, and 18% vaped. Compared with women not using cannabis, greater proportions of women using cannabis reported alcohol (69% vs. 37%, p < 0.01), cigarette (61% vs. 29%, p < 0.01) and other drug use (16% vs. 4%, p < 0.01). Compared to those with no high potency use, a higher proportion of women using high potency products were in a state legalizing cannabis sales. Cannabis use among women with HIV is common and of variable frequency. Future work should characterize patterns of use, product choice motivations, and associated health impacts in the context of aging and HIV.

Does cannabis and electronic nicotine delivery system (ENDS) use interfere with cigarette smoking cessation in young adulthood?

AIMS

Reducing combustible cigarette smoking is a major public health concern. Research identifies both electronic nicotine delivery systems (ENDS) and cannabis use as factors that are related to combustible cigarette cessation. The current study examined whether using substances in similar ways (e.g., inhaling them) triggers the urge to smoke, thereby undermining attempts to quit.

DESIGN

Analyses examined how using ENDS and smoking or vaping cannabis, both separately and together, were associated with reductions in daily combustible cigarette smoking among young adult smokers.

PARTICIPANTS

Three waves of data from the Community Youth Development Study, including 909 participants who reported daily cigarette smoking at age 23, 26, and/or 28, were included in analyses.

SETTING

Participants were dispersed throughout 48 US states.

MEASUREMENTS

Latent growth modeling was used to model daily cigarette smoking over time. Models using past-month ENDS use, past-month smoking/vaping cannabis, and past-month co-use of ENDS and cannabis (using ENDS and smoking/vaping cannabis within the past month) as time-varying covariates were tested.

FINDINGS

Over time, there was a tendency towards cessation of daily combustible cigarette use among this smoking sample. Smoking/vaping cannabis was associated with a decreased rate of daily combustible cigarette cessation among the sample, whereas ENDS use was associated with an increased rate of daily smoking cessation. The predicted additive effect of using ENDS and smoking/vaping cannabis was not significant.

CONCLUSIONS

Among young adult daily cigarette smokers, smoking cannabis, on its own, poses a risk to quitting combustible cigarettes, while using ENDS may promote cigarette cessation, possibly through substitution.

Associations between cannabis use and same-day health and substance use behaviors

OBJECTIVE

Cannabis use has increased in the United States as states have legalized/decriminalized recreational and/or medicinal use. The primary aim of this study was to examine daily associations between cannabis use and health (physical activity [PA]) and substance use (alcohol consumption, cigarette use) behaviors.

METHOD

Data from a 28-day nationwide study that prompted daily ecological momentary assessments (EMAs) were used to assess daily cannabis use, moderate-to-vigorous PA (MVPA), alcohol containing drinks consumed, and cigarettes smoked. Only participants who reported cannabis use on at least one day during the study period were included in the analysis (N = 98). Generalized linear mixed models were used to examine associations between cannabis use and same-day health and substance use behaviors while adjusting for race, biological sex, and age.

RESULTS

Daily cannabis use was positively associated with daily PA (p = 0.04, 3.31-minute higher PA duration on use vs. non-use days), number of alcohol containing drinks consumed (p = 0.01, 0.45 more drinks on use vs. non-use days), and number of cigarettes smoked (p = 0.01, 0.63 more cigarettes on use vs. non-use days).

CONCLUSIONS

This study was among the first to use EMAs to examine associations between daily cannabis use and same-day PA, alcohol consumption, and cigarette use. Overall, findings indicated that daily cannabis use is associated with higher engagement in these daily health and substance use behaviors. Further research is needed to understand mechanisms linking cannabis use with these and other behaviors.

Quantity of delta-9-tetrahydrocannabinol consumption and cannabis use disorder among daily cannabis consumers

BACKGROUND AND AIMS

Amid escalating cannabis legalization and daily consumption in the United States (US), determining the risk of cannabis use disorder (CUD) and relevant consequences among daily consumers has become a public health priority. Understanding these risks requires valid assessment of the daily quantity of delta-9-tetrahydrocannabinol (THC) consumed and its relation to consequences. This study characterized daily cannabis consumption using a new method for estimating milligrams of THC (mgTHC), and examined the relationship between daily mgTHC and CUD severity in a large national sample of daily consumers.

DESIGN, SETTING AND PARTICIPANTS

US adult (aged 18+ years) daily cannabis consumers (n = 4134) completed a comprehensive online survey of cannabis consumption patterns (e.g. frequency, quantity, product types, potencies, administration methods) and Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) CUD criteria.

MEASUREMENTS

The primary exposure was past-week daily mgTHC consumption, calculated from survey responses to queries about product type, amount and potency consumed and including adjustments for puff size and loss of THC from specific methods of administration. The primary outcomes were (1) number of CUD criteria (range = 0-11) and (2) CUD severity categories: none, mild, moderate, severe.

FINDINGS

Median daily consumption was ~130 mgTHC, with substantial variability (25% ≤ 50 mg and 25% ≥ 290 mg). On average, participants endorsed 2.5 CUD criteria, and 65% met criteria for CUD (39% mild, 18% moderate, 8% severe). Greater daily mgTHC predicted higher CUD criteria count [betalog(mgTHC) = 0.50, 95% confidence interval (CI) = 0.267-0.734] and higher odds of mild [log odds ratio (logOR) = 0.238, 95% CI = 0.184-0.292], moderate (logOR = 0.303, 95% CI = 0.232-0.374) or severe (logOR = 0.335, 95% CI = 0.236-0.435) CUD.

CONCLUSIONS

Among daily consumers of cannabis, there appears to be a positive relationship between the daily quantity of cannabis consumed (measured in milligrams of delta-9-tetrahydrocannabinol) and both the risk and severity of cannabis use disorder.

Prevalence and determinants of cigarette-cannabis co-use among US cancer survivors

PURPOSE

We estimated the prevalence of cigarette-cannabis co-use and investigated the individual-level factors associated with cigarette-cannabis co-use among adult (aged ≥ 18) cancer survivors.

METHODS

We used population-based data from the 2022 Behavioral Risk Factor Surveillance System. The sample included 9,323 (weighted 2,711,650) adult cancer survivors residing in 16 US states and two US territories. The outcome was cigarette-cannabis co-use, examined using multinomial multivariable logistic regression models.

RESULTS

Overall, 81.83% self-reported as white, 58.97% women, and 57.69% aged ≥ 65. About 12.00% reported current cigarette use, 10.36% past 30-day cannabis use, and 3.28% cigarette-cannabis co-use. The odds of cigarette-cannabis co-use were greater for younger survivors (18-49 years), those with high school or less education, not in the workforce, and divorced, separated, widowed, or never married individuals. Further, survivors with ≥ 3 comorbidities (vs. no-comorbidity), ≥ 14 days of poor mental health days (vs. none), and ≥ 14 days of poor physical health (vs. none) in the past month also had increased odds of cigarette-cannabis co-use.

CONCLUSIONS

The study findings suggest that certain subgroups of cancer survivors are more likely to engage in cigarette-cannabis co-use, and these patterns are associated with individual-level factors.

IMPLICATIONS FOR CANCER SURVIVORS

New strategies and tailored interventions targeting cigarette-cannabis co-use among cancer survivors are critically needed to improve the overall well-being of cancer survivors. Future research should explore additional factors to fully understand cigarette-cannabis co-use in cancer survivors.

Effects of Cigarette Smoking and 3-Day Smoking Abstinence on Translocator Protein 18 kDa Availability: A [18F]FEPPA Positron Emission Tomography Study

With the many negative health consequences of cigarette smoking, quitting is known to improve health in multiple domains. Using positron emission tomography/computed tomography (PET/CT) scanning, our group previously demonstrated that smokers have lower levels than nonsmokers of translocator protein binding both acutely and following overnight abstinence. Here, we sought to determine the effects of longer smoking abstinence on this marker of gliosis for microglia and astroglia, as well as explore associations between the marker and smoking-related symptoms. This observational study was performed in an academic VA medical centre. Fifty-nine generally healthy Veterans who were either nonsmokers (n = 15) or smokers (n = 44) participated in the study. Participants completed an intake visit to evaluate for inclusion/exclusion criteria, [18F]FEPPA PET/CT scanning and a structural magnetic resonance imaging scan. Smokers were alternately assigned either to smoke to satiety (n = 24) before scanning or undergo three nights of continuous abstinence prior to scanning using contingency management (n = 20 completed this protocol and scanning). The smoker satiety group had a significantly lower mean whole brain (WB) standardized uptake value (SUV) for [18F]FEPPA binding than both the nonsmoking (-15.3%) and abstinent smoker (-12.3%) groups. The nonsmoking control and abstinent smoker groups had mean WB SUVs that were not significantly different from one another (3.0% group difference). In an exploratory analysis, a significant inverse relationship was found between WB SUVs and mood ratings for smokers, indicating that higher levels of TSPO binding were associated with worse mood. The central findings here support previous studies demonstrating lower levels of the marker for gliosis in satiated smokers and imply normalization with elimination of cigarette smoke constituents from the body, although other explanations for study results (e.g., alterations in radioligand delivery or clearance of radioligand by cigarette smoke constituents) are possible. These findings may represent a previously unknown health benefit of quitting smoking.

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.

Exposure to Secondhand Cannabis Smoke Among Children

Importance

The degree that in-home cannabis smoking can be detected in the urine of resident children is unclear.

Objective

Test association of in-home cannabis smoking with urinary cannabinoids in children living at home.

Design, Setting, and Participants

This cross-sectional study used baseline data from Project Fresh Air, a 2012-2016 randomized clinical trial to reduce fine particulate matter levels. Eligible participants were recruited from households in San Diego County, California, with children under age 14 years and an adult tobacco smoker in residence. Children's urine samples were analyzed in 2022.

Exposures

In-home cannabis smoking, measured by: parent or guardian report of in-home cannabis smoking; number of daily nonspecific smoking events computed via an air particle count algorithm; and number of daily cannabis smoking events ascertained by residualization, adjusting for air nicotine, tobacco smoking, and other air particle generating or ventilating activities.

Main Outcomes and Measures

Levels of the cannabis biomarker Δ9-tetrahydrocannabinol (THC) and its major metabolites, 11-hydroxy-Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol. Biomarker molar equivalents were summed to represent total THC equivalents (TTE) in urine. Logistic regression assessed whether in-home smoking was associated with cannabis biomarker detection. For children with detectable urinary cannabinoids, linear regression assessed in-home smoking association with quantity of urinary TTE.

Results

A total of 275 children were included in analysis (mean [SD] age, 3.6 [3.6] years; 144 male [52.4%]; 38 Black [13.8%], 132 Hispanic [48.0%], and 52 White [18.9%]). Twenty-nine households (10.6%) reported in-home cannabis smoking in the past 7 days; 75 children [27.3%] had detectable urinary cannabinoids. Odds of detectable TTE in children's urine were significantly higher in households with reported in-home cannabis smoking than households without (odds ratio [OR], 5.0; 95% CI, 2.4-10.4) and with each additional ascertained daily cannabis smoking event (OR, 2.5; 95% CI, 1.6-3.9). Although the point estimate for TTE levels was higher among children with detectable urinary cannabinoids and exposure to more daily cannabis smoking events (increase per event, 35.68%; 95% CI, -7.12% to 98.21%), the difference was not statistically significant.

Conclusions and Relevance

In this cross-sectional study, in-home cannabis smoking was associated with significantly increased odds of child exposure to cannabis smoke, as assessed by urinary cannabinoid biomarkers. As young children spend most of their time at home, reducing in-home cannabis smoking could substantially reduce their exposure to the toxic and carcinogenic chemicals found in cannabis smoke.

Frequent recreational cannabis use and its association with caries and severe tooth loss: Findings from the National Health and Nutrition Examination Survey, 2015-2018

BACKGROUND

The aim of this study was to examine the association of frequent recreational cannabis (FRC) use with untreated coronal caries, untreated root surface caries, and severe tooth loss.

METHODS

This cross-sectional study analyzed data obtained from 5,656 people, aged 18 through 59 years, who participated in the National Health and Nutrition Examination Survey from 2015 through 2018. FRC use was defined as self-reported use of marijuana or hashish at least once per month for the past 12 months. Log-binomial and logistic regression analyses were conducted before and after controlling for sociodemographic and behavioral factors to examine the association between FRC use and untreated coronal caries, root surface caries, and severe tooth loss.

RESULTS

Compared with non-FRC users, people reporting FRC use had 17% higher probabilities of having untreated coronal caries (95% CI, 1.02 to 1.35), 55% higher odds of having untreated root surface caries (95% CI, 1.21 to 1.99), and 41% higher odds of having severe tooth loss (95% CI, 1.00 to 1.99) after controlling for age, sex, race or ethnicity, nativity, education, family income to poverty ratio, and alcohol consumption.

CONCLUSIONS

This study suggests that FRC use is associated with increased coronal caries, root surface caries, and severe tooth loss in the US adult population. Further longitudinal studies are warranted to assess the impact of varying frequencies, quantities, and forms of cannabis use.

PRACTICAL IMPLICATIONS

Dental care professionals should be aware that FRC use may be associated with caries and tooth loss.

Nicotine-Containing Electronic Nicotine Delivery Systems (ENDS) Use in the United States, Stratified by Age, National Survey on Drug Use and Health, 2021

Background: Electronic nicotine delivery system (ENDS) use is prevalent in the United States, especially among youth and young adults. It is important to monitor current ENDS use and identify at-risk groups, particularly among tobacco naïve individuals. Methods: Using data from the 2021 National Survey on Drug Use and Health, we examined the prevalence of past 30-day nicotine/tobacco ENDS use and correlates, stratified by age. Results: The prevalence of past 30-day ENDS use was as follows: ages 12-17 (5.0%), ages 18-20 (13.5%), ages 21-25 (14.6%), ages 26-34 (7.2%), and ages ≥35 (2.5%). Among youth ages 12-17, female respondents were more likely to report past 30-day ENDS use compared to male respondents (aOR = 1.41, 95% CI = 1.01-1.97). Among all adult age groups, current cigarette smoking status was associated with an increased likelihood of current ENDS use, versus never smoking. Among all age groups, those reporting non-Hispanic Black, non-Hispanic Other, and Hispanic race/ethnicity had a decreased likelihood of past 30-day ENDS use versus non-Hispanic White respondents, while past-year drug/alcohol use disorder, versus no use disorder, was associated with an increased likelihood of past 30-day ENDS use. Conclusions: ENDS use was most prevalent among young adults and least prevalent among persons ages ≥35. Most youth who reported ENDS use also reported never smoking cigarettes-compared to adults who reported ENDS use, who primarily reported current or former cigarette smoking. Our findings-which have identified characteristics of those most likely to use ENDS products-have the potential to inform screening and targeted intervention efforts aimed at reducing ENDS use.

Trends in cannabis and tobacco co-use in the United States, 2002-2021

BACKGROUND

Co-use of cannabis and tobacco poses greater risks than use of either substance individually and may be becoming more prevalent with increasing cannabis medicalization and legalization. We aimed to assess trends in the prevalence of cannabis and tobacco co-use between 2002-2019 and identify the updated prevalence and correlates of co-use in 2021 among US adults.

METHODS

This study used data from the 2002-2021 National Survey on Drug Use and Health, a nationally-representative, cross-sectional survey in the US. We assessed prevalence trends in past 30-day cannabis and tobacco co-use, exclusive cannabis use, and exclusive tobacco use overall and by sociodemographic group using joinpoint regression. Additionally, multinomial models identified correlates of co-use in 2021.

RESULTS

In 2021, the weighted prevalence of cannabis and tobacco co-use was 6.38 %, the weighted prevalence of exclusive cannabis use was 7.28 %, and the weighted prevalence of exclusive tobacco use was 15.01 %. From 2002 to 2019, the prevalence of past 30-day co-use of cannabis and tobacco increased significantly (annual percentage change [APC]: 1.9 [1.4-2.4], P<0.05) among the overall US population. All subgroups of sex, race/ethnicity, and age also saw significant increases in co-use, other than young adults ages 18-25, for whom co-use was stagnant between 2002-2014 and then decreased significantly between 2014-2019.

CONCLUSION

This study identified increasing cannabis and tobacco co-use overall and among most sociodemographic strata in the US. As cannabis policy changes rapidly, co-use requires closer surveillance, clinical screening, and dedicated research.

Situations and roles of cannabis versus cigarette use: Integrating ecological momentary assessment with qualitative mapping interviews

Use of both cannabis and tobacco has surpassed use of tobacco alone among young adults in California. To better understand why, we collected data with 32 young adults ages 18-30 in Northern California who regularly used cigarettes and cannabis and had diverse sexual, gender, racial, and ethnic identities. Geographically-explicit ecological momentary assessment (EMA; 30 days) was integrated with qualitative mapping interviews. We found contrasting situations of use for cannabis (e.g., around other people) versus cigarettes (e.g., recent discrimination) and different reasons for why participants chose one substance over the other (e.g., enhancing experiences vs. stepping away). Understanding when and why diverse young adults choose cannabis versus cigarettes as they navigate everyday environments helps explain how cannabis and tobacco retail markets shape substance use disparities over time.

Trends in marijuana and heavy alcohol use by cigarette smoking status among US adults: An analysis of the 2002-2019 NSDUH

BACKGROUND

Polysubstance use is associated with adverse health outcomes, yet little research has measured changes in polysubstance use. We aimed to 1) estimate trends in marijuana and heavy alcohol use by cigarette smoking and demographic subgroups, and 2) examine patient factors associated with concurrent use among adults who were smoking.

METHODS

We conducted a repeated cross-sectional analysis of 687,225 non-institutionalized US adults ≥18 years from the 2002-2019 National Survey on Drug Use and Health. Participants were stratified into current, former, and never smoking groups. Main outcomes were prevalence of heavy alcohol use, marijuana use, and concurrent use of both substances.

RESULTS

From 2002-2019, heavy alcohol use declined from 7.8 % to 6.4 %, marijuana use rose from 6.0 % to 11.8 %, and concurrent use of alcohol and marijuana remained stable. Among adults who were smoking from 2005 to 2019, higher education was associated with higher odds of heavy alcohol use, while older ages, female gender, non-White race/ethnicity, and government-provided health insurance were associated with lower odds. The odds of marijuana use decreased in females, older ages, and higher incomes while increasing in people with poorer health status, higher education, government-provided or no health insurance, and serious mental illness. Compared to White adults who were smoking, Black counterparts had higher odds of marijuana use (OR=1.23; 95 %CI: 1.15-1.29), while Hispanic (OR=0.68; 95 %CI: 0.63-0.72) and other racial/ethnic identities (OR=0.83; 95 %CI: 0.77-0.90) had lower odds.

CONCLUSIONS

Our study suggests marijuana use might not be sensitive to changes in the use of tobacco and alcohol.

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.

Testing a Brief Quitline Intervention for Tobacco Cannabis Co-Users: A Randomized Controlled Pilot Study

Background: Tobacco cannabis co-use is common and becoming more prevalent. Frequent and heavy users of cannabis may struggle to quit smoking. Quitlines offer free cessation treatment in the United States and 25% of quitline callers may also be cannabis users. The present paper describes a randomized pilot study of a tailored intervention for cannabis and cigarette co-users. The intervention combines the quitline smoking cessation treatment with a motivational enhancement therapy-based cannabis intervention. Methods: The randomized pilot study was conducted within four state-funded quitlines with quitline coaches as interventionists. 102 quitline callers who were cannabis and cigarette co-users were randomized to receive treatment as usual (TAU) or the new Quitline Check-Up (QLCU) intervention. Outcomes were collected 90 days post-randomization. Primary outcomes included feasibility and acceptability of delivering the QLCU in the quitline setting. Secondary outcomes included 7-day point prevalence tobacco abstinence, past 30-day cannabis use, and Cannabis Use Disorder Identification Test scores. Results: Study participants were heavy cannabis users, averaging 25 days of use in the past 30; nearly 70% used at a level considered hazardous. Fidelity ratings indicated coaches were successful at delivering the intervention. Treatment engagement was high for both groups (TAU m = 3.4 calls; QLCU m = 3.6 calls) as was treatment satisfaction. Intent-to-treat quit rates (with survey non-responders classified as smokers) were 28.6% for the TAU control group and 24.5% for the QLCU group (P = .45). Discussion: Hazardous cannabis use rates were high in this sample of tobacco cannabis co-users calling quitlines to quit smoking. The intervention for co-users was acceptable and feasible to deliver. No improvements in tobacco cessation outcomes were observed. Pragmatic intervention development within a real-world clinical setting can streamline the intervention development process. More research is needed on tobacco cannabis co-users and who can benefit from a tailored intervention. Registered: ClinicalTrials.gov NCT04737772, February 4, 2021.

Evolving Disparities in Cannabis Use Among Youth by Demographics and Tobacco and Alcohol Use in the U.S.: 2013-2021

INTRODUCTION

This study investigated the prevalence of past 30-day cannabis use among U.S. youth by cigarette use, alcohol use, demographics, and state-of-residence cannabis legal status in 2021 and examined whether changes in cannabis use prevalence were modified by these factors from 2013 to 2021.

METHODS

Data were drawn from the 24 states that collected cannabis use data participating in the Youth Risk Behavior Surveillance System from 2013 to 2021. Logistic regression analyses estimated past 30-day cannabis prevalence in 2021 and produced AORs by current cigarette, alcohol, and state-of-residence cannabis legal status. The same method was used with year as the exposure, adjusting for sex, race, and ethnicity, to assess trends in prevalence from 2013 to 2021.

RESULTS

In 2021, cannabis use was more common among female youth (16.75% vs 13.83% [AOR=1.26, 95% CI=1.16, 1.37]) and non-Hispanic Black and Hispanic youth than among non-Hispanic White youth (17.19%, 16.14% vs 14.60% [AOR=1.25, 95% CI=1.12, 1.39 and AOR=1.16, 95% CI=1.04, 1.29, respectively]). Cannabis use was much more common among youth who reported any past 30-day cigarette or alcohol use (44.90% vs 6.48% [AOR=11.80, 95% CI=10.57, 13.18]). Declines in cannabis use were observed independent of state-level cannabis law from 2013 to 2021, and cannabis use prevalence did not differ significantly by state-of-residence cannabis legal status among the 24 participating states in 2021.

CONCLUSIONS

Public health officials should carefully consider the potential impact of expanding commercialization of cannabis as a wellness product on youth cannabis use, especially with regard to minoritized populations and co-use with tobacco and alcohol. National and state-level public health education on cannabis use and youth-oriented prevention of cannabis uptake are long overdue.

Cannabis Use Disorder Symptoms in Weekly Cannabis Users: A Network Comparison Between Daily Cigarette Users and Nondaily Cigarette Users

Background: Concurrent use (co-use) of cannabis and tobacco is common and associated with worse clinical outcomes compared with cannabis use only. The mechanisms and interactions of cannabis use disorder (CUD) symptoms underlying co-use remain poorly understood. Methods: We examined differences in the symptom presence and symptom network configurations between weekly cannabis users who use tobacco daily (co-users, n=789) or non- or nondaily (nondaily co-users, n=428). Results: First, we identified a range of symptoms (craving, failed reduce or quit attempts, neglected responsibilities, and negative social effects) that are most central to the highly interconnected CUD symptom network. Risky cannabis use was mostly associated with negative social and health effects, and independent of other CUD symptoms. Craving symptoms act as a bridge between different CUD and withdrawal symptoms. Among co-users, (1) craving is more strongly associated with negative psychosocial effects, (2) feelings of depression and negative health effects are more central to the network, and (3) the negative health effects are more strongly associated with failed attempts to reduce or quit attempts compared with nondaily co-users. Discussion: Our results go beyond existing findings focused on the mere increase in CUD symptom presence, and speak to the potential synergistic effects of co-use on dependence and withdrawal symptoms. We outline clinical implications with respect to targeting specific CUD symptoms in co-users, and point to future research to disentangle tobacco and cannabis craving symptoms.

The Puzzle of Marijuana Use and Forced Vital Capacity

In study after study, marijuana use has been found to be associated with increased forced vital capacity (FVC). This is puzzling, because marijuana is commonly consumed by inhalation of its smoke, and smoke exposure of any kind is not generally considered a cause of increased FVC. Although this observation was first made decades ago, a satisfactory explanation remains elusive. In this review we survey the evidence supporting the relationship between marijuana use and increased FVC, discuss potential threats to validity when inferring causation, and, presupposing a possible causal relationship, pose two key questions. First, what are possible physiologic or pathophysiologic mechanisms by which marijuana use might increase FVC? Second, why might this effect be consistently observed with marijuana use but not with tobacco use? Explanations for the first question include lung and chest growth and remodeling from strenuous marijuana smoke inhalation and reductions in lung elastic recoil from marijuana smoke exposure. Explanations for the second include differences between marijuana and tobacco in smoke composition and patterns of consumption, such as smoking topography. Finally, the possibility that smoke, whether from marijuana or tobacco, might have nonmonotonic effects on FVC depending on the degree of exposure is explored. In synthesizing a curated breadth of epidemiologic and physiologic science, we leverage a perplexing observation to generate potential insights and avenues for further research into the biological effects of smoke, from marijuana or otherwise, on the respiratory system.

Classification of patterns of tobacco and cannabis co-use based on temporal proximity: A qualitative study among young adults

PURPOSE

Co-use of tobacco and cannabis is a common and complex behavior. The lack of harmonized measures of co-use yields confusion and inconsistencies in synthesizing evidence about the health effects of co-use. We aimed to classify co-use patterns based on temporal proximity and describe preferred products and motives for each pattern in order to improve co-use surveillance.

METHODS

We conducted semi-structured interviews in a sample of 34 young adults (Mage = 22.8 years, 32.4 % female) during 2017-2019 in California, USA. We employed a qualitative thematic analysis to identify timing, reasons, and contexts for tobacco and cannabis co-use and classify co-use patterns.

RESULTS

Four emergent patterns of co-use with increasing temporal proximity between tobacco use and cannabis use were: Same-month different-day co-use (Pattern 1); Same-day different-occasion co-use (Pattern 2); Same-occasion sequential co-use (Pattern 3); and Same-occasion simultaneous co-use (Pattern 4). Participants used various product combinations within each pattern. Similar motives for all patterns were socialization, product availability, and coping with stress/anxiety. Unique motive for temporally distant patterns (Patterns 1 and 2) was seeking substance-specific effects (e.g., stimulant effect from nicotine, relaxation effects from cannabis), while unique motives for temporally close patterns (Patterns 3 and 4) were seeking combined effects from both substances (e.g., more intense psychoactive effects, mitigating cannabis adverse effects) and behavioral trigger (e.g., cannabis use triggers tobacco use).

CONCLUSIONS

Our classification of co-use patterns can facilitate consistency for measuring co-use and assessing its health impacts. Future research should also measure product types and motives for different patterns to inform intervention efforts.

Perception of harm is strongly associated with complete ban on in-home cannabis smoking: a cross-sectional study

BACKGROUND

Perception of health risk can influence household rules, but little is known about how the perception of harm from cannabis secondhand smoke (cSHS) is related to having a complete ban on in-home cannabis smoking. We examined this association among a nationally representative sample of United States adults.

METHODS

Respondents were 21,381 adults from the cross-sectional Marijuana Use and Environmental Survey recruited from December 2019-February 2020. Perceived harm of cSHS exposure (extremely harmful, somewhat harmful, mostly safe, or totally safe) and complete ban of cannabis smoking anywhere in the home (yes or no) were self-reported. Logistic regression for survey-weighted data estimated covariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) for the association between perceived harm of cSHS and complete ban on in-home cannabis smoking. Stratified subgroup analyses (by cannabis smoking status, cannabis use legalization in state of residence, and children under age 6 living in the home) were conducted to quantify effect measure modification of the association between perception of harm and complete ban.

RESULTS

A complete ban on in-home cannabis smoking was reported by 71.8% of respondents. Eight percent reported cSHS as "totally safe"; 20.5% "mostly safe"; 38.3% "somewhat harmful"; and 33.0% "extremely harmful". Those who reported cSHS as "extremely harmful" had 6 times the odds of a complete ban on in-home cannabis smoking (OR = 6.0, 95%CI = 4.9-7.2) as those reporting smoking as "totally safe". The odds of a complete ban were higher among those reporting cSHS as "somewhat harmful" (OR = 2.6, 95%CI = 2.2-3.1) or "mostly safe" (OR = 1.4, 95%CI = 1.2-1.7) vs those reporting cSHS as "totally safe". In each subgroup of cannabis smoking status, state cannabis use legalization, and children under the age of 6 living in the home, perceived harm was associated with a complete ban on in-home cannabis smoking.

CONCLUSIONS

Our study demonstrates perceiving cSHS as harmful is strongly associated with having a complete in-home cannabis smoking ban. With almost a third of US adults perceiving cSHS as at least "mostly safe", there is strong need to educate the general population about potential risks associated with cSHS exposure to raise awareness and encourage adoption of household rules prohibiting indoor cannabis smoking.

The Combined Effects of Nicotine and Cannabis on Cortical Thickness Estimates in Adolescents and Emerging Adults

Early life substance use, including cannabis and nicotine, may result in deleterious effects on the maturation of brain tissue and gray matter cortical development. The current study employed linear regression models to investigate the main and interactive effects of past-year nicotine and cannabis use on gray matter cortical thickness estimates in 11 bilateral independent frontal cortical regions in 223 16-22-year-olds. As the frontal cortex develops throughout late adolescence and young adulthood, this period becomes crucial for studying the impact of substance use on brain structure. The distinct effects of nicotine and cannabis use status on cortical thickness were found bilaterally, as cannabis and nicotine users both had thinner cortices than non-users. Interactions between nicotine and cannabis were also observed, in which cannabis use was associated with thicker cortices for those with a history of nicotine and tobacco product (NTP) use in three left frontal regions. This study sheds light on the intricate relationship between substance use and brain structure, suggesting a potential modulation of cannabis' impact on cortical thickness by nicotine exposure, and emphasizing the need for further longitudinal research to characterize these interactions and their implications for brain health and development.

In-Home Cannabis Smoking Among a Cannabis-Using Convenience Sample from the Global Drug Survey: With Weighted Estimates for U.S. Respondents

Introduction: Secondhand and thirdhand tobacco smoke exposure most often occur at home, but little is known about occurrences of in-home cannabis smoking. We ascertained in-home cannabis smoking reported by all cannabis-using (i.e., used in the last 12 months) respondents to the Global Drug Survey (GDS; international-GDS sample), and among U.S. cannabis-using respondents (US-GDS sample). Materials and Methods: We used data collected November 2019-January 2020 for the 2020 GDS, an annual anonymous, cross-sectional survey; respondents were 16+ years old, from 191 countries. We estimated any and daily in-home cannabis smoking in the last 30 days among international-GDS respondents (n=63,797), using mixed effects logistic regression. US-GDS respondents (n=6,580) were weighted to the covariate distribution of the nationally representative 2018 National Survey on Drug Use and Health cannabis-using sample, using inverse odds probability weighting, to make estimates more generalizable to the U.S. cannabis-using population. Results: For the international-GDS cannabis-using respondents, any in-home cannabis smoking was reported by 63.9% of men, 61.9% of women, and 68.6% of nonbinary people; and by age (<25 years old=62.7%, 25-34 years old=65.0%, and 35+ years old=62.8%). Daily in-home cannabis smoking was highest among nonbinary (28.7%) and respondents 35+ years of age (28.0%). For the weighted US-GDS cannabis-using respondents, any in-home cannabis smoking was reported by 49.8% of males and 61.2% of females; and by age (<25 years old=62.6%, 25-34 years old=41.8%, 35+ years old=57.9%). Weighted daily in-home smoking was 23.2% among males and 37.1% among females; by age (<25 years old=34.8%, 25-34 years old=27.8%, and 35+ years old=21.6%). Conclusions: There was high daily cannabis smoking in homes of international-GDS and US-GDS respondents who used cannabis in the last 12 months. In part, due to cannabis legalization, the number of users worldwide has increased over the past decade. Criminal stigma historically associated with cannabis continues to drive those users indoors. In this context, our findings support further investigation of cannabis use behavior to understand how often people are exposed to secondhand and thirdhand cannabis smoke and the consequences of that exposure.

Anxiety sensitivity reduction-smoking cessation intervention among individuals who engage in dual cigarette and cannabis use: A secondary analysis

INTRODUCTION

Cannabis use among individuals who smoke is prevalent in the general population and related to adverse health effects, including higher levels of interoceptive perturbation (i.e., a disturbance in internal experiences). An important aspect of smoking cessation among individuals who co-use cannabis is to address behavioral associations between physiological sensations and habitual behaviors via integrated treatments focused on reducing reactivity to internal perturbations such as anxiety sensitivity (i.e., the belief that such symptoms produce personal harm).

METHODS

The current study involved a secondary analysis of a randomized clinical trial (RCT) of an integrated anxiety sensitivity-smoking cessation intervention compared to standard smoking cessation. The current study sought to extend findings from the initial trial to examine if the integrated intervention produced better smoking cessation outcomes than standard care among individuals who engage in dual cigarette and cannabis use. Participants were 149 adults who engage in dual cigarette and cannabis use (41.6 % female; Mage = 30.89, SD = 13.1).

RESULTS

Results indicated that the anxiety sensitivity intervention produced statistically significant differences in distal (long-term) smoking abstinence at 3-, 6-, and 12-month follow-up assessments but not proximal (short-term; quit-week to 2-weeks) smoking abstinence.

CONCLUSIONS

Overall, the potential of an integrated anxiety sensitivity smoking cessation intervention to yield better long-term smoking abstinence rates than standard cessation treatment among individuals who engage in dual cigarette and cannabis use is clinically significant.

Awareness and interest in cannabis use for cancer management among cancer survivors

BACKGROUND

We examined the awareness, interest, and information sources relating to cannabis use for cancer management (including management of cancer symptoms and treatment-related side effects) and determined factors associated with cancer survivors' awareness and interest in learning about cannabis use for cancer management.

METHODS

This was a cross-sectional study of adult cancer survivors (N = 1886) receiving treatment at a comprehensive cancer center. Weighted prevalence and multivariable logistic regression analyses were conducted.

RESULTS

Among cancer survivors, 88% were aware and 60% were interested in learning about cannabis use for cancer management. Common sources of information to learn about cannabis use for cancer management were cancer doctors/nurses (82%), other patients with cancer (27%), websites/blogs (26%), marijuana stores (20%), and family/friends (18%). The odds of being aware of cannabis use for cancer management was lower among male compared to female survivors (adjusted odds ratio [AOR]: 0.61; 95% confidence interval [CI]: 0.41-0.90), non-Hispanic Blacks compared to non-Hispanic Whites (AOR: 0.36; 95% CI: 0.21-0.62), and survivors who do not support the legalization of cannabis for medical use compared to those who do (AOR: 0.10; 95% CI: 0.04-0.23). On the other hand, the odds of being interested in cannabis use for cancer management was higher among non-Hispanic Blacks compared to non-Hispanic Whites (AOR: 1.65; 95% CI: 1.04-2.62), and among cancer survivors actively undergoing cancer treatment compared to patients on non-active treatment (AOR: 2.25; 95% CI: 1.74-2.91).

CONCLUSION

Awareness of cannabis use for cancer management is high within the cancer survivor population. Results indicated health care providers are leading information source and should receive continued medical education on cannabis-specific guidelines. Similarly, tailored educational interventions are needed to guide survivors on the benefits and risks of cannabis use for cancer management.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

Tobacco and Cannabis Use Have a Synergistic Association on Infection Risk Following Total Knee Arthroplasty

BACKGROUND

Studies suggest an increase in the number of combined users of tobacco and cannabis. Therefore, we specifically assessed tobacco, cannabis, and combined users who underwent primary total knee arthroplasty (TKA) to determine 90-day to 2-year: (1) odds of periprosthetic joint infection; (2) odds of revision; and (3) medical complications.

METHODS

We queried a national, all payer database of patients undergoing primary TKA between 2010 and 2020. Patients were stratified according to current use of tobacco products (n = 30,000), cannabis (n = 400), or a combination (n = 3,526). These were defined according to International Classification of Disease codes, Ninth and Tenth Editions. Patients were tracked from the 2 years before TKA through 2 years afterwards. A fourth group of TKA recipients who did not have tobacco nor cannabis use was used as a matching cohort. Periprosthetic joint infections (PJIs), revisions, and other medical/surgical complications from 90 days through 2 years were evaluated between these cohorts using bivariate analyses. Multivariate analyses assessed independent risk factors for PJI at 90 days through 2 years, adjusted for patient demographics and health metrics.

RESULTS

Combined tobacco and cannabis use were associated with the highest rates of PJI following TKA. The odds of 90-day PJI risk among cannabis, tobacco, and combined users was 1.60, 2.14, and 3.39, respectively, as compared to the matched cohort (P < .001). Co-users had the highest and significantly increased revision odds at 2 years following TKA (odds ratio = 1.52, 95% confidence interval, 1.15 to 2.00). At 1 and 2 years following TKA, cannabis, tobacco, and co-users had higher rates of myocardial infarctions, respiratory failures, surgical site infections, and manipulations under anesthesia when compared to the matched cohort (all P < .001).

CONCLUSION

Tobacco and cannabis use before primary TKA demonstrated a synergistic association on PJI risk from 90 days through 2 years. Although the harms of tobacco use are well-known, this additional knowledge about cannabis should be incorporated in the shared decision-making discussions in the pre-operative setting to best prepare for expected risks following primary TKA.

Associations of polygenic risk scores for smoking heaviness and lifetime cannabis use with tobacco and cannabis co-use trajectories among African Americans

BACKGROUND

We aimed to identify distinct trajectories of tobacco, cannabis, and their co-use among African Americans, and to investigate whether these patterns were associated with polygenic risk scores (PRS) for tobacco and cannabis use.

METHOD

Participants (N=428 participants; 50.9% male) were initially recruited for an elementary school-based prevention in a Mid-Atlantic city when they were in first grade. From ages 14-26, participants reported on their frequency of tobacco and cannabis use in the past year during annual assessments. DNA was collected from participants at age 21. PRS for smoking heaviness (i.e., cigarettes per day) and lifetime cannabis use were created based on genome-wide association study results derived from Liu et al. (2019) and Pasman et al. (2018), respectively.

RESULTS

We identified five distinct trajectories of tobacco and cannabis co-use, including (1) Low Tobacco and Cannabis Use, (2) Adolescent Limited Tobacco and Cannabis Use, (3) Experimental Cannabis, Young Adult Increasing Tobacco, (4) Experimental Tobacco, Young Adult Increasing Cannabis, and (5) High, Chronic Tobacco and Cannabis Use. Compared to the Low Tobacco and Cannabis Use subgroup, individuals in the High, Chronic Tobacco and Cannabis Use subgroup had greater PRS for smoking heaviness, and individuals in the Experimental Cannabis, Young Adult Increasing Tobacco subgroup had higher PRS for lifetime cannabis use.

CONCLUSIONS

Polygenic risk for lifetime cannabis use and smoking heaviness is associated with the developmental progression of tobacco and cannabis co-use among African Americans, furthering knowledge on the etiology of co-use in this population.

Stagnant daily smoking prevalence between 2008 and 2019 among Black and Hispanic adults with serious psychological distress

BACKGROUND

Racial/ethnic minority status and mental illness independently drive inequity in cigarette smoking and related morbidity. Racial/ethnic minority groups suffer a disproportionate burden of tobacco-related diseases. People with serious mental illness (SMI) smoke at up to 7 times the rate of the general population. There is a need to quantify smoking prevalence and trends among people at the intersection of both groups.

METHODS

This study analyzes 2008-2019 data from the National Survey on Drug Use and Health. Linear time trends of daily smoking prevalence were assessed among people with serious psychological distress (SPD; marker for SMI) and people without SPD reporting White, Black, Hispanic, and Other race/ethnicity using logistic regression, with survey year as the predictor. Models with year-by-smoking status interaction terms and F-tests assessed differential time trends.

RESULTS

The prevalence of daily smoking among people without SPD decreased over time among people reporting White (aOR=0.96, p<0.001), Black (aOR=0.96, p<0.001), Hispanic (aOR=0.95, p<0.001), and Other (aOR=0.97, p=0.002) race/ethnicity. Among people with SPD, the smoking prevalence decreased among people with White race/ethnicity (aOR=0.95, p<0.001), with no significant changes among people of Black, Hispanic, and Other race/ethnicity.

CONCLUSIONS

Smoking among people with SPD who report Black and Hispanic race/ethnicity has not changed significantly in the past 11 years, despite decreasing among non-SPD and White groups. People who are Black/Hispanic and people with SPD struggle to quit smoking, which is amplified intersectionally. Tailored interventions may be a better mechanism to reduce barriers to smoking cessation in this population.

The Association Between Cannabis Use and Subsequent Nicotine Electronic Cigarette Use Among US Adolescents

PURPOSE

The current study assessed the association between cannabis use among youth never e-cigarette users and subsequent e-cigarette use.

METHODS

The Population Assessment of Tobacco and Health Study is a nationally representative cohort study. Participants aged 12 years and older were selected using a 4-stage, stratified probability sample design from the US civilian, noninstitutionalized population. We included adolescents who participated in both wave 4.5 (2017-2018) and wave 5 (2018-2019) of Population Assessment of Tobacco and Health, and were never e-cigarette users at baseline (N = 9,925). Through multivariable logistic regressions, we examined the prospective association between cannabis use and subsequent e-cigarette use.

RESULTS

E-cigarette use at wave five was significantly more common among youth cannabis users at wave 4.5. The adjusted relative risks between ever cannabis use and subsequent past 12-month, past 30-day, and frequent e-cigarette use (≥20 days per month) were 1.53 (95% CI, 1.26-1.81), 1.70 (95% CI, 1.25-2.15), and 2.10 (95% CI, 1.17-3.03), respectively. The adjusted relative risks between past 30-day cannabis use and subsequent past 12-month, past 30-day, and frequent e-cigarette use were 1.54 (95% CI, 1.04-2.28), 2.01 (95% CI, 1.23-3.29), and 2.87 (95% CI, 1.44-5.71), respectively. We also found significant associations between ever cannabis vaping with subsequent e-cigarette use.

DISCUSSION

While previous research associates e-cigarette use with subsequent onset of cannabis use, we identify a reverse directional effect, where adolescent cannabis use is associated with increased likelihood of future e-cigarette use.

Latent Classes of Tobacco and Cannabis Use among Youth and Young Adults in the United States

Background: Research characterizing patterns of tobacco and cannabis use by product type and route of administration among youth and young adults (YAs) is limited. Methods: We conducted latent class analysis of tobacco and cannabis use (i.e., cigarettes, electronic nicotine delivery systems (ENDS), cigars, blunts, cannabis vaping, and other cannabis use (without blunting/vaping)) among youth (ages 15-17) and YAs (ages 18-24) who used at least one product in the past 30 days, using data from the Population Assessment of Tobacco and Health Study (Wave 4, 2016-2017). We used multinomial logistic regression models to examine associations between sociodemographic characteristics and use classes. Results: The latent use classes for youth included cigarettes (2.5%), ENDS (2.6%), blunts (2.5%), other cannabis (6.3%), ENDS + cannabis vaping (2.7%), and cigarettes + cigars + other cannabis (1.5%), while the latent use classes for YAs included cigarettes (11.7%), ENDS (3.9%), blunts (5.3%), other cannabis (7.0%), cigarettes + cigars (8.2%), and cigarettes + ENDS + cannabis vaping (4.9%). We compared use classes to never/former use for youth (82.0%) and YAs (59.0%) and found that they differed by each sociodemographic characteristic. For example, non-Hispanic Black YAs had higher odds of cigarettes + cigar use compared to non-Hispanic White YAs, whereas racial/ethnic minority youth and YAs had lower odds of other dual/poly use groups compared to their non-Hispanic White counterparts. Conclusions: We observed differences in use classes by sociodemographic characteristics for youth and YAs. Health professionals must consider tobacco and cannabis use patterns when implementing prevention and cessation interventions.

Racial/ethnic discrimination and tobacco and cannabis use outcomes among US adults

INTRODUCTION

Racial/ethnic discrimination (hereafter, discrimination) is associated with use of individual tobacco and cannabis products. However, we know little about how discrimination affects dual/polytobacco and cannabis use and associated use disorders.

METHODS

We used cross-sectional data on adults (18+) from the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions-III (n = 35,744). We defined past-year discrimination as a summary scale (range: 0-24) based on six scenarios. We created a mutually exclusive six-category use variable: noncurrent, individual tobacco and noncannabis, individual tobacco and cannabis, individual cannabis and nontobacco, dual/polytobacco and noncannabis, and dual/polytobacco and cannabis based on past 30-day tobacco use of four products (i.e., cigarettes, electronic nicotine delivery systems, other combustibles (cigars, pipe), smokeless tobacco) and cannabis use. We also examined past-year tobacco use disorder (TUD) and cannabis use disorder (CUD) as a four-level variable: no disorders, TUD only, CUD only, and TUD and CUD. We estimated associations between discrimination and each outcome using adjusted multinomial logistic regression and assessed effect modification by stratifying adjusted models by race/ethnicity (i.e., Hispanic, non-Hispanic (NH) White, NH Black, and another race/ethnicity).

RESULTS

Experiencing more discrimination was associated with each outcome but was most strongly associated with dual/polytobacco and cannabis use (OR: 1.13, 95 % CI: 1.07-1.19) and joint TUD and CUD (OR: 1.16, 95 % CI: 1.12-1.20). Models stratified by race/ethnicity showed that discrimination was associated with dual/polytobacco and cannabis only among NH White adults, and with joint TUD and CUD only among NH Black and NH White adults.

CONCLUSIONS

Discrimination was associated with tobacco and cannabis use outcomes among multiple adult racial/ethnic populations, but associations were more profound for NH White and NH Black adults than adults from other racial/ethnic populations.

Prevalence of depressive symptoms and cannabis use among adult cigarette smokers in Canada: cross-sectional findings from the 2020 International Tobacco Control Policy Evaluation Project Canada Smoking and Vaping Survey

BACKGROUND

Tobacco smoking and cannabis use are independently associated with depression, and evidence suggests that people who use both tobacco and cannabis (co-consumers) are more likely to report mental health problems, greater nicotine dependence and alcohol misuse than those who use either product exclusively. We examined prevalence of cannabis use and depressive symptoms among Canadian adults who smoke cigarettes and tested whether co-consumers of cannabis and tobacco were more likely to report depressive symptoms than cigarette-only smokers; we also tested whether cigarette-only smokers and co-consumers differed on cigarette dependence measures, motivation to quit smoking and risky alcohol use by the presence or absence of depressive symptoms.

METHODS

We analyzed cross-sectional data from adult (age ≥ 18 yr) current (≥ monthly) cigarette smokers from the Canadian arm of the 2020 International Tobacco Control Policy Evaluation Project Four Country Smoking and Vaping Survey. Canadian respondents were recruited from Leger's online probability panel across all 10 provinces. We estimated weighted percentages for depressive symptoms and cannabis use among all respondents and tested whether co-consumers (≥ monthly use of cannabis and cigarettes) were more likely to report depressive symptoms than cigarette-only smokers. Weighted multivariable regression models were used to identify differences between co-consumers and cigarette-only smokers with and without depressive symptoms.

RESULTS

A total of 2843 current smokers were included in the study. The prevalence of past-year, past-30-day and daily cannabis use was 44.0%, 33.2% and 16.1%, respectively (30.4% reported using cannabis at least monthly). Among all respondents, 30.0% screened positive for depressive symptoms, with co-consumers being more likely to report depressive symptoms (36.5%) than those who did not report current cannabis use (27.4%, p < 0.001). Depressive symptoms were associated with planning to quit smoking (p = 0.01), having made multiple attempts to quit smoking (p < 0.001), the perception of being very addicted to cigarettes (p < 0.001) and strong urges to smoke (p = 0.001), whereas cannabis use was not (all p ≥ 0.05). Cannabis use was associated with high-risk alcohol consumption (p < 0.001), whereas depressive symptoms were not (p = 0.1).

INTERPRETATION

Co-consumers were more likely to report depressive symptoms and high-risk alcohol consumption; however, only depression, and not cannabis use, was associated with greater motivation to quit smoking and greater perceived dependence on cigarettes. A deeper understanding of how cannabis, alcohol use and depression interact among people who smoke cigarettes is needed, as well as how these factors affect cessation activity over time.

Cannabis and nicotine co-use among primary care patients in a state with legal cannabis access

The aim of this exploratory analysis was to evaluate cannabis exposure, reasons for use and problematic cannabis use among adult primary care patients in Washington state (United States) who co-use cannabis and nicotine (tobacco cigarettes and/or nicotine vaping) compared to patients who endorse current cannabis use only. As part of a NIDA Clinical Trials Network (CTN) parent study, patients who completed a cannabis screen as part of routine primary care were randomly sampled (N = 5,000) to a receive a confidential cannabis survey. Patients were stratified and oversampled based on the frequency of past-year cannabis use and for Black, indigenous, or other persons of color. Patients who endorsed past 30-day cannabis use are included here (N = 1388). Outcomes included; prevalence of cannabis use, days of cannabis use per week and times used per day, methods of use, THC:CBD content, non-medical and/or medical use, health symptoms managed, and cannabis use disorder (CUD) symptom severity. We conducted unadjusted bivariate analyses comparing outcomes between patients with cannabis and current nicotine co-use to patients with cannabis-only use. Nicotine co-use (n = 352; 25.4 %) was associated with differences in method of cannabis use, THC:CBD content, days of use per week and times used per day, number of health symptoms managed, and CUD severity (all p < 0.001), compared to primary care patients with cannabis-only use (n = 1036). Interventions targeting cannabis and nicotine co-use in primary care are not well-established and further research is warranted given findings of more severe cannabis use patterns and the adverse health outcomes associated with co-use.

Have recreational marijuana laws undermined public health progress on adult tobacco use?

Public health experts caution that legalization of recreational marijuana may normalize smoking and undermine the decades-long achievements of tobacco control policy. However, very little is known about the impact of recreational marijuana laws (RMLs) on adult tobacco use. Using newly available data from the Population Assessment of Tobacco and Health (PATH) and dynamic difference-in-differences and discrete-time hazard approaches, we find that RML adoption increases prior-month marijuana use among adults ages 18-and-older by 2-percentage-points, driven by an increase in marijuana initiation among prior non-users. However, this increase in adult marijuana use does not extend to tobacco use. Rather, we find that RML adoption is associated with a lagged reduction in electronic nicotine delivery systems (ENDS) use, consistent with the hypothesis that ENDS and marijuana are substitutes. Moreover, auxiliary analyses from the National Survey on Drug Use and Health (NSDUH) show that RML adoption is associated with a reduction in adult cigarette smoking. We conclude that RMLs may generate tobacco-related health benefits.

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.

Inhibition of Nicotine Metabolism by Cannabidiol (CBD) and 7-Hydroxycannabidiol (7-OH-CBD)

Cannabis-based products have experienced notable increases in co-usage alongside tobacco products. Several cannabinoids exhibit inhibition of a number of cytochrome P450 (CYP) and UDP glucuronosyltransferase (UGT) enzymes, but few studies have examined their inhibition of enzymes involved in nicotine metabolism. The goal of the present study was to examine potential drug-drug interactions occurring in the nicotine metabolism pathway perpetrated by cannabidiol (CBD) and its active metabolite, 7-hydroxy-CBD (7-OH-CBD). The inhibitory effects of CBD and 7-OH-CBD were tested in microsomes from HEK293 cells overexpressing individual metabolizing enzymes and from human liver tissue. Assays with overexpressing microsomes demonstrated that CBD and 7-OH-CBD inhibited CYP-mediated nicotine metabolism. Binding-corrected IC50,u values for CBD inhibition of nicotine metabolism to cotinine and nornicotine, and cotinine metabolism to trans-3'-hydroxycotinine (3HC), were 0.27 ± 0.060, 0.23 ± 0.14, and 0.21 ± 0.14 μM, respectively, for CYP2A6; and 0.26 ± 0.17 and 0.029 ± 0.0050 μM for cotinine and nornicotine formation, respectively, for CYP2B6. 7-OH-CBD IC50,u values were 0.45 ± 0.18, 0.16 ± 0.08, and 0.78 ± 0.23 μM for cotinine, nornicotine, and 3HC formation, respectively, for CYP2A6, and 1.2 ± 0.44 and 0.11 ± 0.030 μM for cotinine and nornicotine formation, respectively, for CYP2B6. Similar IC50,u values were observed in HLM. Inhibition (IC50,u = 0.37 ± 0.06 μM) of 3HC to 3HC-glucuronide formation by UGT1A9 was demonstrated by CBD. Significant inhibition of nicotine metabolism pathways by CBD and 7-OH-CBD suggests that cannabinoids may inhibit nicotine metabolism, potentially impacting tobacco addiction and cessation.

The Endocannabinoid System as a Potential Therapeutic Target for HIV-1-Associated Neurocognitive Disorder

Background: Despite the successful introduction of combined antiretroviral therapy, the prevalence of mild to moderate forms of HIV-associated neurocognitive disorders (HAND) remains high. It has been demonstrated that neuronal injury caused by HIV is excitotoxic and inflammatory, and it correlates with neurocognitive decline in HAND. Endocannabinoid system (ECS) protects the body from excitotoxicity and neuroinflammation on demand and presents a promising therapeutic target for treating HAND. Here, we firstly discuss the potential pathogenesis of HAND. We secondly discuss the structural and functional changes in the ECS that are currently known among HAND patients. We thirdly discuss current clinical and preclinical findings concerning the neuroprotective and anti-inflammatory properties of the ECS among HAND patients. Fourth, we will discuss the interactions between the ECS and neuroendocrine systems, including the hypothalamic-pituitary-adrenocortical (HPA) and hypothalamic-pituitary-gonadal (HPG) axes under the HAND conditions. Materials and Methods: We have carried out a review of the literature using PubMed to summarize the current state of knowledge on the association between ECS and HAND. Results: The ECS may be ideally suited for modulation of HAND pathophysiology. Direct activation of presynaptic cannabinoid receptor 1 or reduction of cannabinoid metabolism attenuates HAND excitotoxicity. Chronic neuroinflammation associated with HAND can be reduced by activating cannabinoid receptor 2 on immune cells. The sensitivity of the ECS to HIV may be enhanced by increased cannabinoid receptor expression in HAND. In addition, indirect regulation of the ECS through modulation of hormone-related receptors may be a potential strategy to influence the ECS and also alleviate the progression of HAND due to the reciprocal inhibition of the ECS by the HPA and HPG axes. Conclusions: Taken together, targeting the ECS may be a promising strategy to alleviate the inflammation and neurodegeneration caused by HIV-1 infection. Further studies are required to clarify the role of endocannabinoid signaling in HIV neurotoxicity. Strategies promoting endocannabinoid signaling may slow down cognitive decline of HAND are proposed.

Determining the impact of cannabis use and severity on tobacco cessation outcomes: study protocol for a prospective tobacco treatment trial

BACKGROUND

Several evidence-based tobacco cessation treatment strategies exist, though significant barriers to cessation remain which must be addressed to improve abstinence rates for sub-populations of those smoking cigarettes. Cannabis co-use among those who use tobacco is common and appears to be increasing among adults in the United States (US). The literature evaluating the impact of cannabis use on tobacco cessation has been mixed and has several important limitations, which precludes development of treatment recommendations specific to individuals who use tobacco and co-use cannabis. To date, no prospective studies have evaluated the impact of cannabis use and severity on tobacco cessation or quantified cannabis use changes during tobacco treatment to assess for concurrent reductions, abstinence, or compensatory (i.e., increased) cannabis use. This study's aims are to: (1) evaluate tobacco cessation outcomes among participants who co-use cannabis compared to participants only using tobacco, (2) using daily diaries and biochemical verification, assess changes in cannabis use during tobacco treatment, and (3) assess for a dose-dependent impact of cannabis use on tobacco cessation.

METHOD

A multi-site, prospective, quasi-experimental 12-week tobacco treatment trial enrolling treatment-seeking adults (ages 18-40; N = 208) from three sites across South Carolina (US) who use tobacco daily and oversampling (2:1) those who co-use cannabis. Participants receive tobacco cessation pharmacotherapy (varenicline) paired with behavioral support, while cannabis use is not addressed as part of treatment. The primary outcome is 7-day point prevalence tobacco abstinence at the week 12 end of treatment visit, measured via biochemical verification and self-report. Secondary outcome measures include changes in cannabis use (via biochemical verification and self-report) during tobacco cessation treatment.

DISCUSSION

Results from this trial have the potential to inform tobacco treatment among those co-using cannabis, which may require a tailored approach to address the role of cannabis in quitting tobacco.

TRIAL REGISTRATION

The trial is registered with ClinicalTrials.gov: NCT04228965. January 14th, 2020.

Increased vulnerability to atrial and ventricular arrhythmias caused by different types of inhaled tobacco or marijuana products

BACKGROUND

The emergence of a plethora of new tobacco products marketed as being less harmful than smoking, such as electronic cigarettes and heated tobacco products, and the increased popularity of recreational marijuana have raised concerns about the potential cardiovascular risk associated with their use.

OBJECTIVE

The purpose of this study was to investigate whether the use of novel tobacco products or marijuana can cause the development of proarrhythmic substrate and eventually lead to arrhythmias.

METHODS

Rats were exposed to smoke from tobacco, marijuana, or cannabinoid-depleted marijuana, to aerosol from electronic cigarettes or heated tobacco products, or to clean air once per day for 8 weeks, following by assays for blood pressure, cardiac function, ex vivo electrophysiology, and histochemistry.

RESULTS

The rats exposed to tobacco or marijuana products exhibited progressively increased systolic blood pressure, decreased cardiac systolic function with chamber dilation, and reduced overall heart rate variability, relative to the clean air negative control group. Atrial fibrillation and ventricular tachycardia testing by ex vivo optical mapping revealed a significantly higher susceptibility to each, with a shortened effective refractory period and prolonged calcium transient duration. Histological analysis indicated that in all exposure conditions except for air, exposure to smoke or aerosol from tobacco or marijuana products caused severe fibrosis with decreased microvessel density and higher level of sympathetic nerve innervation.

CONCLUSION

These pathophysiological results indicate that tobacco and marijuana products can induce arrhythmogenic substrates involved in cardiac electrical, structural, and neural remodeling, facilitating the development of arrhythmias.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

Differences between adults who smoke cigarettes daily and do and do not co-use cannabis: Findings from the 2020 ITC four country smoking and vaping survey

BACKGROUND

Little is known about population-level differences between adults who exclusively smoke cigarettes and those who smoke cigarettes and also use cannabis (co-consumers). Thus, this study describes differences on sociodemographic, cigarette-dependence, health and behavioral variables, and risk perceptions associated with smoking cannabis.

METHODS

This cross-sectional study included 6941 respondents from the 2020 ITC Four Country Smoking and Vaping Survey (US, Canada, Australia, England). Adult daily cigarette smokers were included and categorized as: cigarette-only smokers (never used cannabis/previously used cannabis, but not in the past 12 months, n = 4857); occasional co-consumers (cannabis use in the past 12 months, but < weekly use, n = 739); or regular co-consumers (use cannabis ≥ weekly, n = 1345). All outcomes were self-reported. Regression models were conducted on weighted data.

RESULTS

Overall, 19.9 % of respondents reported regular cannabis co-use and 10.1 % reported occasional co-use. Regular co-use was highest in Canada (27.2 %), followed by the US (24.4 %), England (12.7 %) and Australia (12.3 %). Compared to cigarette-only smokers, regular co-consumers were more likely to be male and report chest/breathing problems (p < 0.001). All co-consumers were more likely to be younger, have lower income, be experiencing financial stress, reside in Canada, have depressive symptoms, use alcohol more frequently and binge drink, use other tobacco/nicotine products, and perceive smoking cannabis as low health risk and less harmful than smoking cigarettes (all p < 0.001). Cigarette dependence measures were similar between co-consumers and cigarette-only smokers (all p ≥ 0.05).

CONCLUSIONS

Although there were no differences on cigarette dependence measures between daily cigarette smokers who do and do not use cannabis, there are several other risk factors that may affect tobacco use and abstinence among co-consumers (e.g., greater depression, high-risk alcohol consumption). Thus, tobacco cessation treatment may require multi-pronged strategies to address other health behaviors. Continued surveillance is needed to determine the nature and health implications of co-use considering changing policies, markets, and products.

Increase in Cannabis Use Among Adults With Rheumatic Diseases: Results From a 2014-2019 United States Observational Study

OBJECTIVE

Despite advances in treatments and outcomes among patients with rheumatic diseases, there is an unmet need in pain management. Cannabis has emerged as a potential opioid-sparing alternative, with arthritic pain as a commonly cited reason for medicinal cannabis use. However, little is known, and we set out to understand patterns of cannabis use in a US-wide rheumatic disease population.

METHODS

The study included participants in FORWARD, The National Databank for Rheumatic Diseases. Participants were asked in 2014 and 2019 about their past and current cannabis use. Demographic characteristics, patient-reported outcomes, medications, comorbidities, and diagnoses were compared between cannabis users and non-users with t-tests, chi-square tests, logistic regression, and geographic assessment.

RESULTS

Among 11,006 respondents, cannabis use increased from 6.3% in 2014 to 18.4% in 2019, with the greatest prevalence of use in states where cannabis use was legalized. Most users (74% and 62% in 2014 and 2019, respectively) reported that cannabis was effective in the relief of arthritis symptoms. Cannabis users were more likely to be taking weak opioids (odds ratio 1.2 [95% confidence interval 1.0, 1.5], P = 0.03), to have a history of smoking tobacco (odds ratio 1.7 [95% confidence interval 1.5, 2.1], P < 0.001), and had worse measures on all assessed patient-reported outcomes.

CONCLUSION

Reported cannabis use in this cohort increased significantly between 2014 and 2019. Characteristics of users suggest that those who try cannabis are feeling worse symptomatically, and their pain management needs may not be adequately addressed by other therapies. The association between cannabis, opioids, and patient-reported outcomes highlight areas for future work.

Factors affecting tobacco, nicotine, and cannabis product use among California young adults during the COVID-19 pandemic: A qualitative study

The effects of COVID-19 on tobacco use and cannabis has been variable, and it is unclear the extent to which factors affecting changes in tobacco and cannabis use differ. The purpose of this study was to identify the COVID-19-related factors that affect changes in tobacco and cannabis use during the pandemic. Focus groups with 114 young adults in California in April 2021 were held to discuss tobacco and cannabis use patterns, adverse events, and the effect of COVID-19 on tobacco and cannabis product use. Factors affecting changes in use were largely similar between tobacco products and cannabis products. Drivers of increased cannabis use distinct from tobacco or nicotine product use included feeling greater freedom to disengage and perceptions of less harm. Increases in product use were a result of changing social environment, coping with emotional and psychological distress, and product related factors. Decreases in product use were a result of social isolation, COVID-19-related health concerns, disruptions in daily patterns of living, and reduced access. Improved understanding of how the pandemic has affected tobacco and cannabis use can inform tailored interventions to both support those who have decreases or quit and assist those who have increased use during the pandemic to reduce or cease their consumption.

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.

Impact of cannabis legalization in the United States on trends in cannabis use and daily cannabis use among individuals who smoke cigarettes

BACKGROUND

Cannabis legalization and increases in cannabis use are occurring rapidly in the United States (US). Cannabis and tobacco are often used together, but it is unclear whether cannabis legalization will differentially affect cannabis use among those using cigarettes. This study estimated changes from 2004 to 2017 in the prevalence of cannabis use and daily cannabis use by cigarette use status and examined whether state-level cannabis policy modified these trends.

METHODS

Public and restricted-use data from the 2004-2017 National Survey on Drug Use and Health were analyzed. Weighted logistic regressions were used to examine time trends in past-30-day cannabis use and daily caunabis use by cigarette use and cannabis law status from 2004 to 2017.

RESULTS

Cannabis use and daily use increased significantly among those with and without cigarette smoking. Cannabis use and daily cannabis use were consistently 2-10x more common throughout this time among those with, versus without, cigarette smoking. In 2017, cannabis use and daily cannabis use were substantially more common among individuals who use cigarettes, and even greater among those who live in states where cannabis was legal for medical or recreational (i.e., non-medical) use.

CONCLUSIONS

Cannabis use and daily cannabis use are increasing among US individuals who both smoke and do not smoke cigarettes. Cannabis and daily cannabis use are more common among those who smoke cigarettes and elevated even further among those residing in states that have legalized cannabis for recreational (i.e., non-medical) use. Tobacco control efforts should be adjusted to address increases in cannabis use among Americans who smoke cigarettes.

A difference-in-difference approach to examining the impact of cannabis legalization on disparities in the use of cigarettes and cannabis in the United States, 2004-17

AIMS

To estimate the impact of recreational and medical cannabis laws (RCL, MCL) on the use of cannabis and cigarettes in the United States.

DESIGN

A difference-in-difference approach was applied to data from the 2004-17 National Survey on Drug Use and Health (NSDUH).

SETTING

United States.

PARTICIPANTS

Nationally representative cross-sectional survey of Americans aged 12 years and older (combined analytical sample for 2004-17, n = 783 663).

MEASUREMENTS

Data on past-month use of (1) cigarettes and (2) cannabis were used to classify respondents into four groups: cigarette and cannabis co-use, cigarette-only use, cannabis-only use or no cigarette or cannabis use. State of residence was measured by self-report. MCL/RCL status came from state government websites.

FINDINGS

Difference-in-difference analyses suggest that MCL was associated with an increase in cigarette-cannabis co-use overall [adjusted odds ratio (aOR) = 1.09; 95% confidence interval (CI) = 1.02-1.16], with the greatest increases among those aged 50 years and above (aOR = 1.60; CI = 1.39-1.84), married (aOR = 1.19; CI = 1.07-1.31), non-Hispanic (NH) black (aOR = 1.14; CI = 1.02-1.07) and with a college degree or above (aOR = 1.15; CI = 1.06-1.24). MCL was associated with increases in cigarette-only use among those aged 50 years and above (aOR = 1.07; CI = 1.01-1.14) and NH black (aOR = 1.16; CI = 1.06-1.27) and increases in cannabis-only use among those aged 50 years and above (aOR = 1.24; CI = 1.07-1.44) and widowed/divorced/separated (aOR = 1.18; CI = 1.01-1.37). RCL was associated with an increase in cannabis-only use overall (aOR = 1.21; 95% CI = 1.09-1.34), a decline in cigarette-only use overall (aOR = 0.89; 95% CI = 0.81-0.97) and increases in co-use among those who were married (aOR = 1.24; CI = 1.02-1.50) and aged 50 years and above (aOR = 1.37; CI = 1.03-1.84).

CONCLUSIONS

Recreational and medical cannabis legalization have had a varying impact on the use, and co-use, of cannabis and cigarettes in the United States.

The Effects of Nicotine and Cannabis Co-Use During Late Adolescence on White Matter Fiber Tract Microstructure

OBJECTIVE

Co-use of cannabis and nicotine and tobacco products (NTPs) in adolescence/young adulthood is common and associated with worse outcomes than the use of either substance in isolation. Despite this, little is known about the unique contributions of co-use to neurostructural microstructure during this neurodevelopmentally important period. This study sought to investigate the interactive effects of nicotine and cannabis co-use on white matter fiber tract microstructure in emerging adulthood.

METHOD

A total of 111 late adolescent (16-22 years old) nicotine (NTP; n = 55, all past-year cannabis users) and non-nicotine users (non-NTP; n = 56, 61% reporting cannabis use in the past year) completed demographic and clinical interviews and a neuroimaging session comprising anatomical and diffusion-weighted imaging scans. Group connectometry analysis identified white matter tracts significantly associated with the interaction between nicotine group and past-year cannabis use according to generalized fractional anisotropy (GFA).

RESULTS

Nicotine Group × Cannabis Use interactions were observed in the right and left cingulum and left fornix tracts (false discovery rate = 0.053), where greater cannabis use was associated with increased GFA in the cingulum and left fornix, but only when co-used with nicotine.

CONCLUSIONS

This report represents the first group connectometry analysis in late adolescent/young adult cannabis and/or NTP users. Results suggest that co-use of cannabis and NTPs results in a structurally distinct white matter phenotype as compared with cannabis use only, although to what extent this may change over time with more chronic nicotine and cannabis use remains to be examined in future work.

The Effects of Nicotine and Cannabis Co-Use During Late Adolescence on White Matter Fiber Tract Microstructure

OBJECTIVE

Co-use of cannabis and nicotine and tobacco products (NTPs) in adolescence/young adulthood is common and associated with worse outcomes than the use of either substance in isolation. Despite this, little is known about the unique contributions of co-use to neurostructural microstructure during this neurodevelopmentally important period. This study sought to investigate the interactive effects of nicotine and cannabis co-use on white matter fiber tract microstructure in emerging adulthood.

METHOD

A total of 111 late adolescent (16-22 years old) nicotine (NTP; n = 55, all past-year cannabis users) and non-nicotine users (non-NTP; n = 56, 61% reporting cannabis use in the past year) completed demographic and clinical interviews and a neuroimaging session comprising anatomical and diffusion-weighted imaging scans. Group connectometry analysis identified white matter tracts significantly associated with the interaction between nicotine group and past-year cannabis use according to generalized fractional anisotropy (GFA).

RESULTS

Nicotine Group × Cannabis Use interactions were observed in the right and left cingulum and left fornix tracts (false discovery rate = 0.053), where greater cannabis use was associated with increased GFA in the cingulum and left fornix, but only when co-used with nicotine.

CONCLUSIONS

This report represents the first group connectometry analysis in late adolescent/young adult cannabis and/or NTP users. Results suggest that co-use of cannabis and NTPs results in a structurally distinct white matter phenotype as compared with cannabis use only, although to what extent this may change over time with more chronic nicotine and cannabis use remains to be examined in future work.