Table 1.
Characteristics of the Study Population
| Vapers (N = 24) |
Smokers (N = 24) |
Nonusers (N = 24) |
||
|---|---|---|---|---|
| Age* | 24.3 ± 0.8 | 26.0 ± 0.7 | 25.3 ± 0.6 | |
| Gender† | Male | 20 (83.3%) | 20 (83.3%) | 20 (83.3%) |
| Female | 4 (16.7%) | 4 (16.7%) | 4 (16.7%) | |
| Race† | White | 7 (29.2%) | 7 (29.2%) | 7 (29.2%) |
| Hispanic | 5 (20.8%) | 5 (20.8%) | 5 (20.8%) | |
| African American | 2 (8.3%) | 2 (8.3%) | 2 (8.3%) | |
| Asian | 8 (33.3%) | 8 (33.3%) | 8 (33.3%) | |
| Other‡ | 2 (8.3%) | 2 (8.3%) | 2 (8.3%) | |
| Marital status† | Single and never married | 20 (83.3%) | 19 (79.2%) | 21 (87.5%) |
| Married | 2 (8.3%) | 2 (8.3%) | 1 (4.2%) | |
| Currently living with someone | 2 (8.3%) | 1 (4.2%) | 2 (8.3%) | |
| Widowed | 0 (0%) | 0 (0%) | 0 (0%) | |
| Separated | 0 (0%) | 0 (0%) | 0 (0%) | |
| Divorced | 0 (0%) | 2 (8.3%) | 0 (0%) | |
| Education† | Less than high school | 0 (0%) | 0 (0%) | 0 (0%) |
| High school diploma or GED | 5 (20.8%) | 3 (12.5%) | 0 (0%) | |
| Some college completed or currently enrolled in college | 13 (54.2%) | 6 (25.0%) | 3 (12.5%) | |
| College degree or higher | 6 (25.0%) | 15 (62.5%) | 21 (87.5%) | |
| Employment status† | Full time | 13 (54.2%) | 15 (62.5%) | 14 (58.3%) |
| Part time | 9 (37.5%) | 7 (29.2%) | 7 (29.2%) | |
| Retired or disability | 1 (4.2%) | 0 (0%) | 0 (0%) | |
| Unemployed | 1 (4.2%) | 2 (8.3%) | 3 (12.5%) | |
| Pretax annual income† | <$15 000 | 1 (4.2%) | 7 (29.2%) | 7 (29.2%) |
| ≥$15 000–<$30 000 | 4 (16.7%) | 4 (16.7%) | 6 (25.0%) | |
| ≥$30 000–<$45 000 | 5 (20.8%) | 6 (25.0%) | 1 (4.2%) | |
| ≥$45 000–<$60 000 | 4 (16.7%) | 1 (4.2%) | 4 (16.7%) | |
| ≥$60 000–<$75 000 | 1 (4.2%) | 5 (20.8%) | 1 (4.2%) | |
| ≥$75 000–<$90 000 | 1 (4.2%) | 0 (0%) | 1 (4.2%) | |
| ≥$90 000–<$105 000 | 1 (4.2%) | 0 (0%) | 2 (8.3%) | |
| ≥$105 000–<$120 000 | 2 (8.3%) | 0 (0%) | 0 (0%) | |
| ≥$120 000 | 5 (20.8%) | 1 (4.2%) | 2 (8.3%) | |
| BMI*,§ | 26.6 ± 1.2 | 26.9 ± 1.1 | 23.9 ± 1.0 | |
| Years smoked* | NA | 7.3 ± 1.1 | NA | |
| Pack year*,¶ | NA | 3.1 ± 0.6 | NA | |
| Years vaped* | 2.9 ± 0.4 | NA | NA | |
| Cumulative e-liquid (ml)*,# | 5,780.1 ± 2,017.5 | NA | NA | |
| E-cig device type† | Cigalike | 1 (4.2%) | NA | NA |
| Mod | 11 (45.8%) | NA | NA | |
| Pod | 8 (33.3%) | NA | NA | |
| Multiple | 4 (16.7%) | NA | NA | |
| E-liquid flavor† | Fruit | 7 (29.2%) | NA | NA |
| Sweet | 3 (12.5%) | NA | NA | |
| Mint or Menthol | 5 (20.8%) | NA | NA | |
| Tobacco | 1 (4.2%) | NA | NA | |
| Multiple | 8 (33.3%) | NA | NA | |
| Plasma cotinine (ng/ml)* | 84.9 ± 13.1** | 76.7 ± 8.6** | 2.6 ± 0.1 | |
| Breath CO (ppm)* | 2.0 ± 0.3 | 12.0 ± 1.6†† | 1.9 ± 0.3 | |
| %COHb* | 0.9 ± 0.07 | 2.5 ± 0.2‡‡ | 0.9 ± 0.05 | |
| Vitamin or multi-vitamin use‖ | 7 (29.2%) | 5 (20.8%) | 6 (25.0%) | |
*Results are expressed as Mean ± 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 or she smoked.
#Cumulative e-liquid is calculated as the total volume of e-liquid (in milliliters) vaped by a person during his or her lifetime.
‖Defined as those who used vitamin or multi-vitamin regularly (≥3 times per week in the past year).
Plasma cotinine levels were measured using a solid-phase competitive ELISA (Abnova Corp.) and exhaled breath CO levels and %COHb were quantitated by a Bedfont Micro Smokerlyzer Breath CO monitor (Bedfont Scientific Ltd.) (see, Supplementary Materials).
**Statistically significant as compared to nonusers, p < .0001.
††Statistically significant as compared to nonusers, p = .0005.
‡‡Statistically significant as compared to nonusers, p = .0002.
GED = General Education Development or General Education Diploma, The GED or High School Equivalency Certificate shows that one has a level of knowledge equivalent to a high school graduate, CO = carbon monoxide, ppm = parts per million, COHb = carboxyhemoglobin, NA = Not applicable.