Table 1.

Demographics and smoking history of study participants

Subject characteristics	E-cigarette users n=20	Smokers n=20	Nonsmokers n=19
Age, years	31.3 ± 12.2	41.9 ±11.4	40.6 ± 17.2
Female, N (%)	8 (40.0)	12 (60.0)	14 (73.7)
Race, N (%)
White	20 (100.0)	10 (50.0)	16 (84.2)
Other	0 (0.0)	10 (50.0)	3 (15.8)
Ethnicity, N (%)
Non-Hispanic	20 (100.0)	20 (100.0)	19 (100.0)
Education, N (%)
High school graduate or less	3 (15.8)	9 (45.0)	2 (10.5)
Some college or more	16 (84.2)	11 (55.0)	17 (89.5)
Cigarettes per day	18.7 ± 8.9a	15.9 ± 4.0	N/A
Age of smoking initiation, years	15.9 ± 3.1	14.7 ± 3.6	N/A
Time exclusive e-cigarette use, months	12.2 ± 8.5	N/A	N/A

^aBefore quitting smoking cigarettes