Table 4.

Association Between Youth Observation of E-cigarette Use in or Around School and Susceptibility to Use Cigarettes and E-cigarettes Among Never Tobacco Users, NYTS, 2019 (n=11,518)

	Susceptible to e-cigarette use			Susceptible to cigarette smoking
Observation of e-cigarette use in or around School by grade	Weighted % (95% CI)	AOR (95% CI)a	P-value	Weighted % (95% CI)	AOR (95% CI)a	P-value
Overall
No	26.5 (24.9, 28.1)			24.1 (22.4, 25.8)
Yes	39.5 (38.0, 41.0)	1.7(1.6, 1.9)	<0.0001	26.7 (25.3, 28.1)	1.2 (1.0, 1.3)	0.008
Middle schoolb
No	26.9 (25.0, 28.8)			24.7 (22.6, 26.8)
Yes	43.8 (41.2, 46.4)	1.8 (1.6, 2.1)	<0.0001	31.8 (29.5, 34.1)	1.2 (1.1, 1.4)	0.001
High schoolb
No	25.7 (22.8, 28.7)			22.7 (19.8, 25.7)
Yes	35.8 (33.7, 37.9)	1.6 (1.3, 1.9)	<0.0001	22.3 (20.8, 23.9)	0.9 (0.8, 1.1)	0.53
Interactionc		1.2 (1.0, 1.5)	0.11		1.3 (1.1, 1.7)	0.02

Notes: Boldface indicates statistical significance (p<0.05).

^aMultivariable regression models were performed to assess the association between youth observation of e-cigarette use (predictive variable) and susceptibility to tobacco use (dependent variable) among non-tobacco users. Covariates include sex, race/ethnicity, school level, exposure to cigarette and other tobacco marketing, exposure to e-cigarette marketing, and tobacco use by household members.

^bSeparate analyses were performed on two susceptibility variables (e-cigarette use and cigarette smoking) for all students and were further stratified by middle and high school students.

^cThe results of interaction analysis indicate that, as compared to high schools, middle schools have higher odds of initiating cigarette smoking for students who had observation (versus none) of e-cigarette use.

NYTS, National Youth Tobacco Survey.