One in 10 high school students has used an e-cigarette device to vaporize (vape) cannabis and that practice is associated with cigars, waterpipe and e-cigarette use, findings from a survey of nearly 3,000 adolescents have shown.

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“Although the prevalence of e-cigarette use among youth has increased dramatically in the past decade, little epidemiologic data exist on the prevalence of using e-cigarette devices or other specialised devices to vaporise (‘vape’) cannabis in the form of hash oil, tetrahydrocannabinol (THC) wax or oil, or dried cannabis buds or leaves,” wrote Sarah D. Kowitt, PhD, of the University of North Carolina, Chapel Hill, and colleagues. “This is surprising given that (1) cannabis (also referred to as marijuana) and e-cigarettes are the most commonly used substances by adolescents in the USA, (2) evidence exists that adolescents dual use both tobacco e-cigarettes and cannabis, and (3) longitudinal research suggests that use of e-cigarettes is associated with progression to use of cannabis.”

In a study published in BMJ Open, the researchers used data from the 2017 North Carolina Youth Tobacco Survey, a school-based survey of students in grades 6-12. The study population included 2,835 adolescents in grades 9-12.

Overall, 9.6% of students reported ever vaping cannabis. In multivariate analysis, cannabis vaping was significantly more likely among adolescents who reported using e-cigarettes (adjusted odds ratio 3.18), cigars (aOR 3.76), or water pipes (aOR 2.32) in the past 30 days, compared with peers who didn’t use tobacco.

The researchers found no significant association between smokeless tobacco use or traditional cigarette use in the past 30 days and vaping cannabis.

In a bivariate analysis, vaping cannabis was significantly more common among males vs. females (11% vs. 8.2%) and among non-Hispanic white students (11.3%), Hispanic students (10.5%), and other non-Hispanic students (11.8%) compared with non-Hispanic black students (5.0%).

In addition, prevalence of cannabis vaping increased with grade level, from 4.7% of 9th graders to 15.5% of 12th graders.

The health impacts of vaping cannabis are not well researched, but the researchers note that among the potential safety issues are earlier initiation of tobacco or cannabis use, concomitant tobacco and cannabis use, increased frequency of use or misuse of tobacco or cannabis, or increased potency of cannabis.

The results of the study were limited by several factors including the use of data only from the state of North Carolina, the lack of data on frequency or current vaping cannabis behavior, lack of data on specific products, and lack of data on whether teens used specialized devices or e-cigarettes for cannabis vaping. However, the findings are consistent with studies on prevalence of cannabis vaping in other states such as Connecticut and California. “No studies to our knowledge have examined how adolescents who vape cannabis use other specific tobacco products (i.e., cigarettes, cigars, waterpipe, smokeless tobacco),” the researchers wrote.

The findings confirm that a large number of adolescents who use tobacco products have vaped cannabis as well, and this growing public health issue “is likely to affect and be affected by tobacco control and cannabis policies in states and at the federal level in the USA,” the researchers concluded.

“Increased research investigating how youth use e-cigarette devices for other purposes beyond vaping nicotine, like the current study, is needed,” they added.

The study was supported in part by the National Cancer Institute and the Food and Drug Administration’s Center for Tobacco Products. The researchers had no financial conflicts to disclose.

SOURCE: Kowitt SD et al. BMJ Open. 2019 Jun 13. doi: 10.1136/bmjopen-2018-028535.