Open access Research BMJ Open: first published as 10.1136/bmjopen-2018-028535 on 13 June 2019. Downloaded from Vaping cannabis among adolescents: prevalence and associations with tobacco use from a cross-sectional study in the USA Sarah D Kowitt,1 Amira Osman,2,3 Clare Meernik,4 Gary A Zarkin,5 Leah M Ranney,1 Jim Martin,6 Courtney Heck,6 Adam O Goldstein1,2 To cite: Kowitt SD, Osman A, ABSTRACT Strengths and limitations of this study Meernik C, et al. Vaping Objective Previous research suggests that some cannabis among adolescents: adolescents are using e-cigarette devices to ► Our measure of vaping cannabis has been used prevalence and associations vaporise (‘vaping’) cannabis in the form of hash oil, with tobacco use from previously in nationally representative surveys in tetrahydrocannabinol (THC) wax or oil, or dried cannabis a cross-sectional study the USA. buds or leaves. However, it is unclear how adolescents in the USA. BMJ Open ► Results can only be generalised to adolescents in a who vape cannabis use other tobacco products. This 2019;9:e028535. doi:10.1136/ specific US state (North Carolina). bmjopen-2018-028535 study examined the extent to which adolescents reported ► The survey did not assess frequency or current use ever vaping cannabis and investigated how demographic of vaping cannabis. ► Prepublication history and variables and tobacco behaviours were associated with additional material for this ► The survey did not provide relevant examples of use. paper are available online. To products used to vape cannabis (eg, ‘JuJu Point’ or Design We used cross-sectional data from adolescents view these files, please visit ‘Pax’). (total response rate 64.5%) who participated in the the journal online (http:// dx. doi. ► We were unable to assess whether participants used 2017 North Carolina Youth Tobacco Survey. SAS logistic org/ 10. 1136/ bmjopen- 2018- tobacco e-cigarettes for cannabis or specialised regression survey procedures were used to account for the 028535). cannabis devices. A poster presentation of complex survey design and sampling weights. preliminary results was made Setting North Carolina, USA. Participants Adolescents in high school (n=2835). at the Society for Research on http://bmjopen.bmj.com/ Nicotine and Tobacco (SRNT) Primary outcome and measure Adolescents were asked exist on the prevalence of using e-cigarette annual meeting, February 2019. to indicate whether they had ever used an e-cigarette devices or other specialised devices to vapo- device with marijuana, THC or hash oil, or THC wax. Received 12 December 2018 rise (‘vape’) cannabis in the form of hash Results Approximately 1 in 10 high school students Revised 7 March 2019 oil, tetrahydrocannabinol (THC) wax or reported ever vaping cannabis in the overall sample Accepted 30 April 2019 oil, or dried cannabis buds or leaves.2 This (9.6%). In multivariable models, adolescents who reported using cigars (adjusted OR (aOR) 3.76, 95% CI is surprising given that (1) cannabis (also 2.33 to 6.07), waterpipe (aOR 2.32, 95% CI 1.37 to 3.93) referred to as marijuana) and e-cigarettes or e-cigarettes (aOR 3.18, 95% CI 2.38 to 4.25) in the are the most commonly used substances by on September 30, 2021 by guest. Protected copyright. 3 past 30 days had higher odds of reporting ever vaping adolescents in the USA, (2) evidence exists cannabis compared with their counterparts. There was no that adolescents dual use both tobacco e-cig- significant association between use of smokeless tobacco arettes and cannabis,4 and (3) longitudinal (aOR 0.89, 95% CI 0.42 to 1.91) or use of cigarettes (aOR research suggests that use of e-cigarettes 1.27, 95% CI 0.71 to 2.29) in the past 30 days and odds of is associated with progression to use of reporting ever vaping cannabis. cannabis.5 Conclusions These findings provide evidence that A growing number of studies have exam- large numbers of high school students who use tobacco ined prevalence of vaping cannabis among © Author(s) (or their products have vaped cannabis. As tobacco control 6–8 9–11 policies—such as communication campaigns or smoke- adults and adolescents in the USA. employer(s)) 2019. Re-use For example, a recent study used data from permitted under CC BY-NC. No free laws—increasingly focus on e-cigarettes, attention to commercial re-use. See rights understanding how adolescents use e-cigarettes to vape the 2016 National Youth Tobacco Survey and permissions. Published by substances other than nicotine is essential. (NYTS) and found that 8.9% of middle and BMJ. high school students reported ever vaping For numbered affiliations see cannabis.10 Additionally, the researchers end of article. INTRODUCTION found that prevalence was higher among Correspondence to Although the prevalence of e-cigarette use current e-cigarette users (39.5%) and Dr Sarah D Kowitt; among youth has increased dramatically in current non-e-cigarette tobacco product kowitt@ email. unc. edu the past decade,1 little epidemiologic data users (38.5%).9 10 Other studies have been Kowitt SD, et al. BMJ Open 2019;9:e028535. doi:10.1136/bmjopen-2018-028535 1 Open access BMJ Open: first published as 10.1136/bmjopen-2018-028535 on 13 June 2019. Downloaded from conducted in Connecticut9 and California11 and found device with nicotine; (4) No, I have never used an e-ciga- similar prevalence estimates. While all studies have exam- rette device; and (5) Don’t know/not sure. If participants ined how demographic factors were associated with prev- selected ‘Yes’ to the first response option, they were alence of vaping cannabis,9–11 and one study examined coded as having vaped cannabis. Adolescents selecting how current e-cigarette and other tobacco product use any other response option were coded as never having was associated with prevalence of vaping cannabis,10 no vaped cannabis. studies to our knowledge have examined how adolescents In a previous section of the survey, e-cigarettes were who vape cannabis use other specific tobacco products described as: “battery powered devices that usually (ie, cigarettes, cigars, waterpipe, smokeless tobacco). contain a nicotine-based liquid that is vaporised and The US Food and Drug Administration (FDA) can now inhaled. You may know them as vape-pens, hookah-pens, regulate the manufacture, marketing, sale and distribu- e-hookahs, e-cigars, e-pipes, personal vaporizers or mods. tion of e-cigarettes and their components, including e-liq- Some brand examples include NJOY, Blu, Vuse, MarkTen, uids, cartridges, flavourings and batteries.12 Future FDA Logic, Vapin Plus, eGo and Halo.” regulations for e-cigarettes may take years to implement across the USA; however, there is significant variation in Tobacco use 13 state and local e-cigarette policies, as well as state poli- The survey assessed ever and past 30 days use of five cies related to legal access to cannabis. Therefore, to tobacco products, including: (1) cigarettes, (2) cigars provide evidence on how youth use e-cigarettes to vape (including cigars, little cigars, and cigarillos), (3) smoke- cannabis, which can be useful to state and local author- less tobacco (SLT) (including chewing tobacco, snuff, or ities, we examined the prevalence of vaping cannabis dip; snus; and dissolvable tobacco products), (4) water- among adolescents in North Carolina—a state that pipe (ie, hookah), and (5) e-cigarettes. Using this infor- has not legalised medical or retail cannabis for adults. mation, adolescents were classified as current users of Extending previous research, we examined demographic that tobacco product if they indicated that they had ever variables and tobacco behaviours associated with use. used the product and reported using it on at least 1 day in the past 30 days. Otherwise, participants were coded as non-current tobacco users of the product. METHODS Settings, participants, procedures Demographics We used data from the 2017 North Carolina Youth Tobacco Demographic variables included sex (female or male), Survey (NCYTS). Similar to the NYTS,14 the NCYTS is grade (9th, 10th, 11th, or 12th), race/ethnicity cate- a public and charter school-based survey of students in gorised into non-Hispanic white, non-Hispanic black, grades 6–12. A multi-stage cluster sampling design in http://bmjopen.bmj.com/ Hispanic, or non-Hispanic other race, and whether three distinct regions of the state was used. School districts students reported receiving free or reduced-price lunch were first selected within three geographic regions of the at school (yes or no). state; a school’s probability for selection was proportional to its enrolment size for the survey year. Classes were then randomly selected within each school. Participation was Statistical analysis voluntary and anonymous. Passive consent forms were Of the 3133 high school students, we dropped data for utilised, unless an active consent form was required 62 participants (2%) who had missing or inconsistent responses to whether they had vaped cannabis or not and according to a specific school district policy. Our analyses on September 30, 2021 by guest. Protected copyright. focused on data from high school students. The overall data for 236 participants (7.5%) who had missing data on response rate was 64.5% (75.2% school response rate, any of the other variables examined, creating an analytic 85.8% student response rate), which is similar to the sample of 2835 participants. We first examined correlates 2 response rate from the 2016 NYTS survey (71.6%).15 of vaping cannabis using bivariate χ tests. We then conducted a multivariable logistic regression, including Measures correlates from the bivariate analyses with p<0.10—an Vaping cannabis approach that has been used in previous research.16 Our main outcome of interest was whether adoles- Collinearity among the tobacco use variables and demo- cents had used e-cigarette devices to vape cannabis.