Electronic cigarettes (e-cigarettes) are the most commonly used tobacco product among US youth.1 Cannabis and other substances can be used in e-cigarettes; in 2015, approximately one-third of US middle and high school students reported using e-cigarettes with nonnicotine substances.2 Shifts in social acceptability and access to cannabis could occur as several states consider legalized cannabis sales for adults. Given the high concurrent use of tobacco and other substances,1 it is important to monitor the substances youth use in e-cigarettes. Previous research has assessed e-cigarette cannabis use among students in select grades,3 but no study, to our knowledge, has assessed use among students more broadly, particularly middle school students. This study estimates the national prevalence of self-reported cannabis use in e-cigarettes among US middle and high school students.

Methods

Data were from the 2016 National Youth Tobacco Survey (NYTS), a cross-sectional, school-based survey of US students in grades 6 to 12. The NYTS uses a 3-stage cluster sampling design to provide a nationally representative sample of students attending public and private schools. A total of 20 675 students participated with a response rate of 71.6%. Cannabis use in e-cigarettes was determined by the response “Yes, I have used an e-cigarette device with marijuana, THC [tetrahydrocannabinol] or hash oil, or THC wax,” to the question “Have you ever used an e-cigarette device with a substance besides nicotine?” Other response options included using another substance other than cannabis, using nicotine only, or never using an e-cigarette device. The NYTS data collection was approved by the institutional review board of the Centers for Disease Control and Prevention, Atlanta, Georgia, which waived the need for human subject review for the use of deidentified data.

Analyses were weighted to provide national estimates and to account for the complex sampling design. The prevalence of cannabis use in e-cigarettes was calculated among all students (N = 20 675) and those who ever used e-cigarettes (n = 5217). Assessed correlates included sex, race/ethnicity, school level, current (past 30-day) e-cigarette use, frequency of e-cigarette use, current (past 30-day) use of other tobacco products (cigarettes, cigars, hookah, pipe tobacco, bidis, or smokeless tobacco), and living with someone who uses tobacco products. Statistical significance was determined at P < .05 using pairwise t tests.

Results

Among the 20 675 participants (50.2% male and 49.0% female; 0.8% missing; age range, 9-19 years or older), ever use of cannabis in e-cigarettes was reported by 8.9% of all students (95% CI, 8.1%-9.9%) and 30.6% of those who ever used e-cigarettes (95% CI, 28.3%-33.1%) (Table). Patterns of cannabis use in e-cigarettes were similar among all students and e-cigarette users. Prevalence was significantly higher among male students (10.6% [95% CI, 9.7%-11.6%; P < .001] for all respondents and 33.3% [95% CI, 30.7%-36.0%; P = .005] for e-cigarette users), high school students (12.4% [95% CI, 10.9%-14.2%; P < .001] for all respondents and 33.3% [95% CI, 30.1%-36.6%; P < .001] for e-cigarette users), current users of e-cigarettes (39.5% [95% CI, 35.7%-43.5%; P < .001] for all respondents and 40.3% [95% CI, 36.4%-44.3%; P < .001] for e-cigarette users) or other tobacco products (38.5% [95% CI, 33.9%-43.2%; P < .001] for all respondents and 46.9% [95% CI, 42.3%-51.6%; P < .001] for e-cigarette users), users of e-cigarettes on 20 to 30 days in the past 30 days compared with 1 to 5 or 6 to 19 days (63.7% [95% CI, 55.4%-71.2%; P < .001]), and those who lived with a user of tobacco products (13.0% [95% CI, 11.5%-14.8%; P < .001] for all respondents and 31.7% [95% CI, 29.0%-34.7%; P = .008] for e-cigarette users) (Table). Furthermore, among all students, prevalence was higher among Hispanics than other races/ethnicities (10.8% [95% CI, 9.0%-12.9%; P = .04] for all respondents).

Discussion

Nearly 1 in 11 US students, including one-third of those who ever used e-cigarettes, had used cannabis in e-cigarettes in 2016. Among e-cigarette users, nearly 1 in 3 high school students (1.7 million) and nearly 1 in 4 middle school students (425 000) had ever used cannabis in e-cigarettes. These estimates are consistent with or higher than previous reports of cannabis use in e-cigarettes among US and Canadian students.3-5 Estimates from these studies suggest that from 5%5 to 8%4 of all high school students and from 6%3 to 18%5 of youth who had ever used e-cigarettes had used cannabis in e-cigarettes. However, differences in question wording may limit comparability of estimates across studies.

The US Surgeon General has concluded that e-cigarette aerosol can contain harmful and potentially harmful constituents.1 The National Academies of Sciences has found cannabis use among youth can adversely affect learning and memory and may impair later academic achievement and education.6 Thus, strategies to reduce cannabis use in e-cigarettes are critical for protecting young people from these potential health risks.

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Accepted for Publication: May 6, 2018.

Corresponding Author: Katrina F. Trivers, PhD, MSPH, Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, 4770 Buford Hwy NE, Mail Stop S107-7, Atlanta, GA 30341 (fph1@cdc.gov).

Published Online: September 17, 2018. doi:10.1001/jamapediatrics.2018.1920

Author Contributions: Dr Trivers had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All authors.

Acquisition, analysis, or interpretation of data: Trivers, Phillips, Gentzke, Neff.

Drafting of the manuscript: Trivers, Gentzke, Neff.

Critical revision of the manuscript for important intellectual content: Trivers, Phillips, Gentzke, Tynan.

Statistical analysis: Phillips, Gentzke.

Obtained funding: Neff.

Administrative, technical, or material support: Trivers, Neff.

Supervision: Trivers, Tynan, Neff.

Conflict of Interest Disclosures: None reported.

Disclaimer: The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.