Table 4.

Adjusted odds ratios of school-related and substance-related risk behaviors as a function of frequency categories of past-month e-cigarette use (none, experimental, occasional, and frequent/daily use)

	Truancy (4-week)	Grade point average <= C+	Binge drinking (2-week)	Alcohol use (30-day)	Marijuana use (30-day)	Illicit drug use (30-day)	Nonmedical Rx drug use (30-day)
	(n= 7,430)	(n = 7,640)	(n = 7,578)	(n = 7,667)	(n = 7,792)	(n = 7,573)	(n = 7,620)
	AOR (95% CI)	AOR (95% CI)	AOR (95% CI)	AOR (95% CI)	AOR (95% CI)	AOR (95% CI)	AOR (95% CI)

E-cigarette frequency
Non-user	Ref.	Ref.	Ref.	Ref.	Ref.	Ref.	Ref.
Experimental	2.25 (1.82, 2.77)^***	1.55 (1.17, 2.03)^**	4.22 (3.40, 5.24)^***	5.08 (4.12, 6.26)^***	4.57 (3.71, 5.63)^***	3.40 (1.96, 5.90)^***	2.02 (1.39, 2.95)^***
Occasional	2.37 (1.83, 3.06)^***	1.75 (1.30, 2.37)^***	6.36 (4.94, 8.20)^***	6.91 (5.14, 9.31)^***	5.53 (4.27, 7.16)^***	6.57 (3.94, 10.95)^***	3.42 (2.43, 4.81)^***
Frequent/daily	2.79 (2.12, 3.68)^***	1.83 (1.31, 2.56)^***	6.02 (4.57, 7.93)^***	6.49 (4.83, 8.72)^***	7.52 (5.69, 9.95)^***	8.10 (4.98, 13.17)^***	5.36 (3.78, 7.60)^***

E-cigarette frequency
Experimental	Ref.	Ref.	Ref.	Ref.	Ref.	Ref.	Ref.
Occasional	1.05 (0.77, 1.44)	1.13 (0.77, 1.66)	1.51 (1.11, 2.05)^**	1.36 (0.96, 1.94)	1.21 (0.89, 1.65)	1.93 (1.02, 3.65)*	1.69 (1.07, 2.67)*
Frequent/daily	1.24 (0.89, 1.73)	1.19 (0.78, 1.79)	1.43 (1.03, 1.98)*	1.28 (0.90, 1.81)	1.65 (1.18, 2.29)^**	2.38 (1.29, 4.42)^**	2.65 (1.67, 4.19)^***
Non-user	0.44 (0.36, 0.55)^***	0.65 (0.49, 0.85)^**	0.24 (0.19, 0.29)^***	0.20 (0.16, 0.24)^***	0.22 (0.18, 0.27)^***	0.29 (0.17, 0.51)^***	0.49 (0.34, 0.72)^***

Notes: The sample sizes for the models varied due to missing data on the individual covariates and dependent measures. Illicit drug use consisted of any 30-day use of cocaine, ecstasy, LSD, other hallucinogens, or heroin use. Nonmedical Rx drug use consisted of any nonmedical use of prescription opioids, sedatives, stimulants or tranquilizers. AOR’s were adjusted for sex, race/ethnicity, age, school geographical region, metropolitan statistical area, parental education, and college plans. p < 0.05,

^**

p < 0.01,

^***

p < 0.001.

Data source: 2014 Monitoring the Future Study, Forms 1, 2, 5 and 6.