TABLE 2.

Prevalence and Correlates with “Unassisted Quitting” Method^a

Unassisted Quitting	Weighted %	Unadjusted		Adjustedb
Overall (n = 575)		OR	P	AOR	P
Sex
Male	57.5	Ref	Ref	Ref	Ref
Female	69.2	1.7 (1.1–2.4)	.01	1.7 (1.1–2.6)	.02
Grade
Middle school	57.2	Ref	Ref	Ref	Ref
High school	64.9	1.4 (0.9–2.1)	.11	1.4 (0.9–2.2)	.12
Race/ethnicity
NH white	67.9	Ref	Ref	Ref	Ref
NH Black	62.6	0.8 (0.3–1.9)	.60	0.8 (0.3–1.9)	.56
Hispanic	49.3	0.5 (0.3–0.8)	.01	0.4 (0.3–0.7)	.002
Others	75.5	1.5 (0.5–3.9)	.45	1.6 (0.7–3.7)	.25
Sexual minority
Heterosexual	67.9	Ref	Ref	Ref	Ref
Gay/lesbian	43.9	0.4 (0.2–0.8)	.01	0.6 (0.3–1.2)	.12
Bisexual	64.0	0.8 (0.4–1.6)	.59	0.9 (0.4–1.7)	.70
Unsure	59.5	0.7 (0.3–1.6)	.37	0.7 (0.3–1.7)	.47
Frequency and duration of e-cigarette usec
Low frequency-low duration	72.2	Ref	Ref	Ref	Ref
Low frequency-high duration	63.6	0.7 (0.4–1.2)	.20	0.6 (0.3–1.1)	.12
High frequency-low duration	59.9	0.6 (0.3–1.1)	.11	0.5 (0.2–1.1)	.08
High frequency-high duration	61.6	0.6 (0.4–1.0)	.03	0.5 (0.3–0.9)	.02
Type of e-cigarette used in the past 30 days
A disposable e-cigarette	65.0	Ref	Ref	Ref	Ref
An e-cigarette with prefilled pods or cartridges	67.6	1.1 (0.7–1.8)	.64	1.2 (0.7–2.0)	.44
An e-cigarette with a tank	68.8	1.2 (0.6–2.3)	.61	1.5 (0.8–2.9)	.23
I don’t know the type	43.8	0.4 (0.2–0.8)	.005	0.5 (0.2–1.1)	.08
Multiple tobacco product used
Sole e-cigarette	70.5	Ref	Ref	Ref	Ref
Dual/poly use	54.4	0.5 (0.3–0.7)	.0004	0.7 (0.44–0.97)	.03
Flavor use in e-cigarette
No	53.4	Ref	Ref	Ref	Ref
Yes	65.9	1.7 (1.0–2.9)	.06	1.2 (0.7–2.3)	.48
Perceived harmfulness of e-cigarette usee
No harm/little harm	65.0	Ref	Ref	Ref	Ref
Some harm/a lot of harm	65.8	1.0 (0.6–1.8)	.89	0.9 (0.6–1.5)	.80
Symptoms of nicotine dependence
No	68.1	Ref	Ref	Ref	Ref
Yes	61.4	0.7 (0.5–1.1)	.18	0.8 (0.4–1.3)	.29
Tobacco use by household members
None	62.0	Ref	Ref	Ref	Ref
Other tobacco products	68.3	1.3 (0.8–2.1)	.24	1.2 (0.7–2.0)	.46
E-cigarettes	69.1	1.4 (0.8–2.4)	.26	1.3 (0.7–2.3)	.42
Perceived peer use of e-cigarettesf		1.0 (1.0–1.1)	.24	1.0 (0.9–1.1)	.96

AOR, adjusted odds ratio; NH, non-Hispanic; OR, odds ratio.

^aThe response “I did not use any resources” is exclusive of other cessation methods.

^bMultivariable analysis was conducted using the survey logistic regression model with unassisted quitting (yes versus no) as the outcome variable and all covariates listed in the table as simultaneous regressors. Missing covariate data were managed with multiple imputation using 20 multiply imputed data sets.

^cThe combination of vaping frequency (low, ≤5 days versus high, >6 days in the past 30 days) and vaping duration (low, ≤2 years versus high, >2 years).

^dOther non–e-cigarette tobacco products include cigarettes, cigars (cigars, little cigars, and cigarillos), smokeless tobacco (chewing tobacco, snuff, dip, snus, and dissolvable tobacco), hookahs, pipe tobacco, bidis, and nicotine pouches.

^ePerceived harmfulness of e-cigarette use was assessed by the question, “How much do you think people harm themselves when they use e-cigarettes some days but not every day?” We classified harm perception as a binary variable: “0 = harmless” for those who responded “no harm” or little harm” vs “1 = harmful” for those who responded “some harm” or “a lot of harm.”

^fThis measure was assessed by the question “Out of every 10 students in your grade at school, how many do you think use e-cigarettes?” with the response option of 0 to 10 (continuous).