TABLE 1

E-Cigarette Use Characteristics

CharacteristicE-Cigarette–Only Users,an = 67, Mean (SD) or No. (%)Dual Users,bn = 16, Mean (SD) or No. (%)Controls, n = 20, Mean (SD) or No. (%)Pc
Age16.3 (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 white36 (54%)9 (67%)0
 Asian American or Pacific Islander12 (19%)2 (12%)2 (10%)
 Multiracial10 (15%)3 (19%)0
 Hispanic7 (10%)2 (12%)18 (90%)
Hours since last e-cigaretted1:58 (6:29)2:02 (7:17)N/A>.91
Days used in past 30 d12.8 (8.9)25.5 (6.6)N/A<.001
Sessions per day2.0 (3.6)8.4 (11.6)N/A.05
Usual puffs per sessionN/A.49
 1–414 (21%)1 (7%)
 5–1021 (31%)4 (27%)
 10–1511 (16%)4 (27%)
 >1521 (31%)6 (40%)
Usual length of sessionN/A.97
 1–2 min8 (12%)2 (13%)
 3–5 min16 (24%)4 (27%)
 6–10 min16 (24%)4 (27%)
 >10 min27 (40%)5 (33%)
Usual type of deviceN/A.82
 Vape pen24 (36%)6 (40%)
 Modified17 (25%)4 (27%)
 Juul18 (27%)4 (27%)
 Other or unsure8 (12%)1 (7%)
E-cigarettes contain nicotineN/A.06
 Always21 (31%)9 (60%)
 Sometimes26 (39%)6 (40%)
 Unsure10 (15%)0 (0%)
 Never10 (15%)0 (0%)
Usual flavor of e-cigaretteeN/A
 Fruit37 (55%)10 (67%).42
 Candy11 (16%)2 (13%).77
 Menthol12 (18%)2 (13%).67
 Tobacco5 (8%)2 (13%).46
  • N/A, not applicable.

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

  • b Used 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.

  • c P 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).

  • d The median was reported because of non-normal distribution.

  • e Participants could select >1.