Table 1.

Adolescents’ awareness of using e-cigarettes with nicotine, without nicotine, or not knowing the nicotine concentration of the e-liquid contained in their e-cigarette differs based on demographic characteristics and sources of e-cigarette acquisition

	Prevalence Rates by Nicotine Use Group			Nicotine vs. Nicotine-Free^r			Nicotine vs. Unknown Nicotine^r
Independent Variables	Nicotine-Free	Nicotine	Unknown	OR	95% CI		OR	95% CI
Males	63.8^a	61.1^a	39.6^b	0.98	0.56	1.72	2.47***	1.49	4.11
Age	15.70 (1.47)^a	16.06 (1.42)^a	15.87 (1.28)^a	0.96	0.76	1.22	0.99	0.80	1.22
E-Cigarette Frequency	6.98 (9.06)^a	13.59 (11.33)^b	6.92 (8.71)^a	1.04^*	1.01	1.07	1.04^**	1.01	1.07
Cigarette Smokers	9.9^a	62.7^b	39.1^c	10.80***	5.51	21.17	1.71^*	1.03	2.84
Sources of Acquisition
Friends	48.9^a	35.1^b	55.0^a	0.86	0.48	1.56	0.75	0.44	1.28
Parent/Family	2.8^a	7.6^a	3.6^a	3.03	0.76	12.14	3.06	0.92	10.13
Sibling	7.1^a	4.3^a	8.9^a	0.36	0.10	1.26	0.36	0.11	1.14
Gas Station	7.8^a	19.5^b	10.1^a	2.17	0.91	5.19	2.00	0.98	4.08
Online	9.9^a	15.7^b	4.7^a	1.71	0.70	4.15	3.62^**	1.39	9.39
Mall	1.4^a	3.8^a	0.6^a	3.56	0.43	20.56	5.83	0.55	61.39
Tobacco Shop	12.1^a	34.6^b	13.6^a	1.96	0.92	4.06	2.12^*	1.11	4.08
Other	2.8^a	6.5^a	5.3^a	3.18	0.74	13.63	0.88	0.28	2.71

Note.

p < .05

^**

p < .01

Prevalence rates for continuous variables are presented as mean (standard deviation) and as percentages for dichotomous variables.

Within rows, superscript letters reflect the results of Bonferroni-corrected comparisons among the nicotine status groups used (Chi-square for dichotomous variables; ANOVA for continuous variables). Cell values with different superscript letters assigned to them differ significantly from one another at p < .01. Regarding the multinomial logistic regression analyses, superscript “r” denotes the reference group. All independent variables were entered into the multinomial logistic regression model simultaneously.