TABLE 1.

E-Cigarette Use Characteristics

Characteristic	E-Cigarette–Only Users,a n = 67, Mean (SD) or No. (%)	Dual Users,b n = 16, Mean (SD) or No. (%)	Controls, n = 20, Mean (SD) or No. (%)	Pc
Age	16.3 (1.2)	17.1 (0.96)	16.0 (1.8)	.06
Sex (male)	49 (73%)	12 (80%)	7 (35%)	<.01
Race and/or ethnicity				<.01
Non-Hispanic white	36 (54%)	9 (67%)	0
Asian American or Pacific Islander	12 (19%)	2 (12%)	2 (10%)
Multiracial	10 (15%)	3 (19%)	0
Hispanic	7 (10%)	2 (12%)	18 (90%)
Hours since last e-cigaretted	1:58 (6:29)	2:02 (7:17)	N/A	>.91
Days used in past 30 d	12.8 (8.9)	25.5 (6.6)	N/A	<.001
Sessions per day	2.0 (3.6)	8.4 (11.6)	N/A	.05
Usual puffs per session			N/A	.49
1–4	14 (21%)	1 (7%)
5–10	21 (31%)	4 (27%)
10–15	11 (16%)	4 (27%)
>15	21 (31%)	6 (40%)
Usual length of session			N/A	.97
1–2 min	8 (12%)	2 (13%)
3–5 min	16 (24%)	4 (27%)
6–10 min	16 (24%)	4 (27%)
>10 min	27 (40%)	5 (33%)
Usual type of device			N/A	.82
Vape pen	24 (36%)	6 (40%)
Modified	17 (25%)	4 (27%)
Juul	18 (27%)	4 (27%)
Other or unsure	8 (12%)	1 (7%)
E-cigarettes contain nicotine			N/A	.06
Always	21 (31%)	9 (60%)
Sometimes	26 (39%)	6 (40%)
Unsure	10 (15%)	0 (0%)
Never	10 (15%)	0 (0%)
Usual flavor of e-cigarettee			N/A
Fruit	37 (55%)	10 (67%)		.42
Candy	11 (16%)	2 (13%)		.77
Menthol	12 (18%)	2 (13%)		.67
Tobacco	5 (8%)	2 (13%)		.46

N/A, not applicable.

^aUsed an e-cigarette product in the past 24 h and had NNAL levels <1 ppm of creatinine.

^bUsed an e-cigarette product in the past 24 h, smoked a cigarette in the past 30 d, and had NNAL levels ≥30 ppm of creatinine.

^cP values are the result of comparing 3 groups on age (analysis of variance), sex, and ethnicity (χ²); all e-cigarette characteristics are the result of comparing e-cigarette–only use to dual-use groups (t tests for continuous variables and χ² analyses for categorical variables).

^dThe median was reported because of non-normal distribution.

^eParticipants could select >1.