Trends in Marijuana Vaping and Edible Consumption From 2015 to 2018 Among Adolescents in the US

Abstract

This survey study investigates trends in noncombustible marijuana use from 2015 to 2018 among US adolescents.

There is growing evidence associating adolescent marijuana use with developmental and societal consequences. Noncombustible marijuana use products are more accessible, but data on use trends compared with smoking marijuana have not been available. Vaping has increased rapidly among adolescents,¹ and although pot brownies are not new, commercially manufactured marijuana edibles are now available. The extent to which these products are used by adolescents nationally is unknown. Regional data suggest boys vape more than girls.^2,3,4 There are conflicting reports of sex differences in edible use^4,5 and differences across modes of use for race/ethnicity^2,4 and socioeconomic status (SES).^3,4 We document prevalence and trends from 2015 to 2018 in noncombustible marijuana use and differences by use frequency and sociodemographic characteristics (ie, sex, race/ethnicity, SES, and school urbanicity).

Methods

Monitoring the Future data from 2015 to 2018 included 9097 responses from students in 12th grade on relevant forms; 2989 (32.9%) reported using marijuana in the past 12 months, and of these, 2412 (80.7%) had complete data on modes of use and covariates.⁶ The study was approved by the University of Michigan Institutional Review Board, and informed consent (either passive consent or active [ie, written] consent, per school policy) was obtained from parents for students younger than 18 years and from students 18 years or older. A school in more than 90% of the geographic units selected each year to be nationally representative was surveyed; 54 354 of 67 312 selected students (80.7%) responded. Methods of use included smoking, vaping, and edibles. Frequency of past 30-day use was dichotomized to regular/daily marijuana use (20 or more occasions) or less.⁶ Sex (male or female), race/ethnicity (black, white, Hispanic, Asian, or other), parent education as an SES proxy (at least 1 parent has a college degree vs less education), and school urbanicity (urban, suburban, or rural) were examined.

All analyses were conducted in SAS version 9.4 (SAS Institute) using the survey procedures to incorporate the complex sample design and sampling weight, accounting for the differential probability of selection. Wald tests were used to calculate the P values, and significance was set as a 2-tailed P value less than .05.

Results

In 2018, students reported consuming marijuana through smoking (666 of 746 past-year users [89.3%]; 666 of 2428 students overall [27.4%]), eating (295 of 746 [39.5%]; 295 of 2428 [12.1%]), and vaping (254 of 746 [34.1%]; 254 of 2428 [10.5%]). Among past-year marijuana users from 2015 to 2018, smoking decreased (2015, 643 of 679 [94.7%]; 2018, 666 of 746 [89.3%]), while eating (2015, 217 of 679 [32.0%]; 2018, 295 of 746 [39.5%]) and vaping (2015, 179 of 679 [26.4%]; 2018, 254 of 746 [34.1%]) increased (Figure). In 2018, consuming marijuana through dabbing (227 of 746 past-year users [30.5%]; 227 of 2428 students overall [9.4%]) and drinking (31 of 746 [4.2%]; 31 of 2428 [1.3%]) were also reported.

Figure. Prevalence of Methods of Marijuana Use in the Past 12 Months Among US 12th Graders, 2015-2018.

Error bars indicate 95% CIs.

Most noncombustible users also smoked marijuana. Only 31 of 254 of vapers (12.3%) and 24 of 295 edible consumers (8.1%) did not smoke marijuana in the past year. Daily use was reported by 112 of 639 smokers (17.6%), 69 of 242 vapers (28.5%), and 77 of 288 edible consumers (26.7%).

In multivariable logistic regression analyses (Table), boys had greater odds than girls of vaping and eating marijuana. White adolescents had greater odds than Hispanic adolescents of smoking marijuana, greater odds than black adolescents of vaping and eating marijuana, and lower odds than Asian adolescents of eating marijuana. Youth with lower (compared with higher) SES had lower odds of vaping marijuana. Compared with rural areas, students in urban areas had greater odds of eating and vaping marijuana, and those in suburban areas had greater odds of eating marijuana. Smoking marijuana was less prevalent and eating and vaping marijuana were more prevalent in 2018 than previous years.

Table. Results of Multivariable Logistic Regression Models for Modes of Marijuana Use Among Past-Year Marijuana Users.

Characteristic	Adjusted odds ratio (95% CI)
	Smoking (n = 2412)	Eating (n = 2412)	Vaping (n = 2412)
Sex
Female	1 [Reference]	1 [Reference]	1 [Reference]
Male	0.79 (0.52-1.19)	1.33 (1.10-1.61)a	2.02 (1.63-2.50)b
Race/ethnicity
White	1 [Reference]	1 [Reference]	1 [Reference]
Black	0.74 (0.38-1.42)	0.63 (0.41-0.95)c	0.50 (0.31-0.79)a
Hispanic	0.57 (0.35-0.91)c	1.01 (0.76-1.35)	1.03 (0.70-1.51)
Asian	0.87 (0.51-1.47)	1.38 (1.03-1.84)c	1.22 (0.83-1.79)
Other	0.66 (0.28-1.56)	1.01 (0.61-1.66)	1.04 (0.65-1.66)
≥1 Parent with a college degreed
No	1 [Reference]	1 [Reference]	1 [Reference]
Yes	0.84 (0.55-1.27)	0.87 (0.69-1.09)	1.59 (1.26-2.01)b
School urbanicity
Rural	1 [Reference]	1 [Reference]	1 [Reference]
Urban	0.55 (0.28-1.09)	2.36 (1.73-3.22)b	1.89 (1.26-2.85)a
Suburban	0.73 (0.36-1.45)	1.60 (1.17-2.19)a	1.29 (0.88-1.88)
Year
2018	1 [Reference]	1 [Reference]	1 [Reference]
2015	2.44 (1.45-4.11)b	0.67 (0.49-0.91)c	0.69 (0.50-0.95)c
2016	2.27 (1.34-3.83)a	0.72 (0.53-0.98)c	0.49 (0.35-0.70)b
2017	1.60 (0.91-2.81)	0.90 (0.65-1.24)	0.56 (0.41-0.76)b

^aP < .01.

^bP < .001.

^cP < .05.

^dParent education, defined as having at least 1 parent with a college degree, was used as a proxy for socioeconomic status.

Discussion

From 2015 to 2018, smoking marijuana decreased and vaping and edible use increased among adolescent users. Similar increases have been reported for vaping across substances, although levels of marijuana use overall remained steady.⁶ Modes of use differed by subgroup. As the legal status of marijuana changes, changes in youth behaviors and attitudes should continue to be monitored.

This study has limitations. Monitoring the Future data represent high school seniors, so students who are absent or dropped out are not included. In 2018, response options changed from “in a vaporizer” to “vaping” and “dabbing” became an option, possibly altering response patterns.

Daily use was more common among vape and edible users than smokers. More than one-quarter of students who vaped or used edibles in the past year used marijuana daily in the last month. Health care professionals should consider asking adolescent patients about noncombustible marijuana use to identify heavy users.