Table 2.
Characteristics of the study population.
| Vapers (n = 37) | Smokers (n = 22) | Controls (n = 23) | |
|---|---|---|---|
| Age* | 28.0 ± 1.5 (Range: 21–56) | 36.5 ± 2.9 (Range: 24–66) | 24.0 ± 1.9 (Range: 22–58) |
| Gender† | |||
| Male | 30 (81.1%) | 17(77.3%) | 13 (56.5%) |
| Female | 7 (18.9%) | 5(22.7%) | 10 (43.5%) |
| Race† | |||
| White | 14 (37.9%) | 5 (22.7%) | 2 (8.7%) |
| Hispanic | 10(27.0%) | 1 (4.5%) | 5 (21.8%) |
| African American | 5(13.5%) | 8(36.4%) | 2(8.7%) |
| Asian | 6 (16.2%) | 4 (18.2%) | 11 (47.8%) |
| Other‡ | 2 (5.4%) | 4(18.2%) | 3 (13.0%) |
| BMI*,§ | 27.2 ± 1.1 | 27.6 ± 1.0 | 23.9 ± 1.4 |
| Pack year*,¶ | 5.0 ± 2.2 | 10.3 ± 2.3 | NA |
| Cumulative e-liquid (ml)*,# | 5096.0 ± 3446.5 | NA | NA |
| E-cig device type†,|| | NA | NA | |
| 1st Generation | 3 (8.1%) | ||
| 2nd Generation | 2 (5.4%) | ||
| 3rd Generation | 23 (62.2%) | ||
| 4th Generation | 0 (0%) | ||
| Multiple | 1st and 3rd: 1 (2.7%); 2nd and 3rd: 7 (18.9%); 1st, 2nd, and 3rd: 1 (2.7%) | ||
| Plasma cotinine (ng/ml)* | 115.0 ± 9.1 | 121.0 ± 11.2 | 2.5 ± 0.1 |
| Years smoked* | 8.0 ± 1.6 | 21.0 ± 2.7 | NA |
| Years vaped* | 3.0 ± 0.3 | NA | NA |
| Elapsed time (years) since last cigarette smoked* | 2.0 ± 0.7 | NA | NA |
NA not applicable.
*Results are expressed as Median ± SE.
†Numbers and percentages (inside brackets) are indicated.
‡Other = Multiracial or Native American.
§BMI: Body Mass Index [Weight (kg) ÷ Height2 (m)].
¶Pack Year is calculated by multiplying the number of packs of cigarettes a person smoked per day by the number of years he/she smoked.
#Cumulative e-liquid is calculated as the total volume of e-liquid (in milliliter) vaped by a person during his/her lifetime.
||Device types are divided into 1st Generation: Cig-a-Like, disposable; 2nd Generation: Vape Pen, mid-size (laser pointer) with pre-filled or re-fillable cartridges; 3rd Generation: Mod or Tank, large size; 4th Generation: Pod, Pod Mod, or Pod-type, small-size, USB-shaped or other sleek designs, pre-filled or re-fillable (JUUL, JUUL-alike); and Multiple: a combination of different generation devices.