Table 1.
Study Sample Characteristics by E-cigarette Use at Wave 1
| Daily e-cig use (N = 299) % (95% CI) |
Non-daily e-cig use (N = 1523) % (95% CI) |
No current e-cig use (N = 6379) % (95% CI) |
p | |
|---|---|---|---|---|
| Age | <.001 | |||
| 18–34 | 43 (37 to 50) | 46 (44 to 49) | 37 (36 to 38) | |
| 45–54 | 36 (29 to 43) | 39 (36 to 42) | 39 (38 to 41) | |
| ≥55 | 21 (16 to 27) | 14 (12 to 17) | 24 (22 to 25) | |
| Male sex | 59 (52 to 66) | 52 (50 to 55) | 55 (54 to 56) | .07 |
| Race/ethnicity | <.001 | |||
| Hispanic | 7 (4 to 10) | 11 (10 to 13) | 11 (10 to 12) | |
| Non-Hispanic white | 82 (77 to 86) | 74 (71 to 77) | 68 (67 to 70) | |
| Non-Hispanic black | 6 (4 to 10) | 8 (6 to 10) | 15 (14 to 16) | |
| Non-Hispanic other | 5 (3 to 8) | 7 (5 to 9) | 6 (5 to 6) | |
| Education | <.001 | |||
| Less than HS | 14 (11 to 19) | 12 (10 to 14) | 17 (16 to 18) | |
| HS or GED | 38 (31 to 45) | 35 (32 to 38) | 39 (38 to 41) | |
| Some college | 36 (29 to 43) | 39 (37 to 42) | 33 (32 to 34) | |
| 4-year college degree or higher | 12 (9 to 17) | 14 (12 to 15) | 11 (10 to 12) | |
| Income as percentage of federal poverty level | .32 | |||
| <100% | 36 (30 to 42) | 35 (33 to 38) | 38 (36 to 40) | |
| 100%–199% | 26 (21 to 33) | 27 (25 to 30) | 28 (26 to 29) | |
| ≥200% | 38 (30 to 45) | 37 (34 to 40) | 34 (33 to 36) | |
| Cigarettes per day, mean (SE) | 11.2 (0.7) | 14.2 (0.3) | 13.6 (0.2) | <.001 (daily vs. non-daily and daily vs. no current use) |
| First cigarette within 30 mins of waking | 67 (60 to 72) | 62 (59 to 65) | 60 (58 to 61) | .06 |
Missing data were 2% or fewer for all variables except income, for which 7% of data were missing. CI = confidence interval; GED = General Education Diploma; HS = high school.