Table 3.

Comparison of Results From Survey-Weighted Unadjusted Regression, Survey-Weighted Adjusted Regression, and Survey- and Inverse Propensity-Weighted Regression

	Unadjusted regression OR (95% CI), p	Adjusted regression OR (95% CI), p	IPW regression OR (95% CI), p
Ever e-cigarette use on ever smoking	17.23 (14.86 to 19.97), p < .001	5.63 (4.71 to 6.73), p < .001	2.49 (1.77 to 3.51), p < .001
Ever e-cigarette use on current smoking	35.86 (15.85 to 81.11), p< .001	4.45 (1.73 to 11.40), p =.002	2.17 (0.62 to 7.63), p = .228
Current e-cigarette use on ever smoking	22.08 (16.19 to 30.13), p < .001	3.79 (2.53 to 5.68), p < .001	2.32 (1.66 to 3.25), p < .001
Current e-cigarette use on current smoking	16.46 (10.22 to 26.50), p < .001	1.37 (0.66 to 2.84), p = .403	0.95 (0.55 to 1.60), p = .849

Results are presented as odds ratio (OR), p value, and 95% confidence interval (CI). Inverse propensity weighting (IPW) accounted for covariates (grade, sex, race, current alcohol use, current marijuana use, lifetime use of other illicit substances, perceived peer smoking, perceived exposure to health warnings on cigarette packaging, frequency of getting disciplined for misbehavior, willingness to break rules for new and exciting experiences, positive mood, disapproval of smoking, dissatisfaction being near people smoking, highest level of education of father), bolded if p < .05. E-cigarette = electronic cigarette.