TABLE 1

Sample Characteristics

CharacteristicWave 1Wave 2
Overall Sample (N = 13 651), n (%)Past 30-d Regular E-cigarette Users (N = 281), n (%)Overall Sample (N = 12 172), n (%)Past 30-d Regular E-cigarette Users (N = 330), n (%)
Age, y
 12–146997 (50.4)46 (15.3)6266 (50.7)67 (19.2)
 15–176653 (49.6)235 (84.7)5906 (49.3)263 (80.8)
Sex
 Male6993 (51.3)182 (65.4)6225 (51.3)201 (60.0)
 Female6657 (48.7)99 (34.6)5918 (48.7)129 (40.0)
Race or ethnic group
 Non-Hispanic white9471 (70.7)219 (80.3)7832 (69.7)254 (82.9)
 Non-Hispanic African American2086 (15.2)19 (6.6)1826 (15.7)13 (4.6)
 Other2093 (14.1)43 (13.1)1823 (14.6)50 (12.5)
Cigarette smoker
 Current smoker634 (4.6)148 (49.4)481 (4.0)149 (44.1)
 Ever smoker1186 (8.7)78 (30.7)938 (7.7)84 (25.7)
 Nonsmoker11 792 (86.7)54 (19.8)10 720 (88.4)95 (30.2)