Table 1.
Descriptive characteristics of the total sample (n=3,729), never smokers (n= 2,596), and never e-cigarette users (n = 1,597) by wave.
| Total sample | Never smokers | Never e-cigarette users | ||||
|---|---|---|---|---|---|---|
| Baseline | Follow-up | Baseline | Follow-up | Baseline | Follow-up | |
| (n = 2,123) | (n = 1,606) | (n = 1,383) | (n = 1,213) | (n = 860) | (n= 737) | |
| Sex, % | ||||||
| Female | 50.2 | 53.4 | 53.6 | 55.2 | 53.8 | 54.8 |
| Male | 49.8 | 46.6 | 46.4 | 44.8 | 46.2 | 45.2 |
| School grade, % | ||||||
| 7th–8th grade | 27.7 | 23.0 * | 36.5 | 26.8 ** | 43.7 | 30.3 ** |
| 9th grade | 29.7 | 32.7 | 31.5 | 37.5 | 27.1 | 38.8 |
| 10th grande | 26.9 | 27.6 | 20.6 | 24.2 | 18.7 | 21.3 |
| 11th–12th grade | 15.7 | 16.7 | 11.4 | 11.5 | 10.5 | 9.6 |
| Parents education, % | ||||||
| High-school or less | 18.7 | 17.9 * | 18.4 | 18.1 | 17.3 | 17.6 |
| University | 73.0 | 70.6 | 72.3 | 69.8 | 72.1 | 69.6 |
| Don’t know | 8.3 | 11.5 | 9.3 | 12.1 | 10.6 | 12.8 |
| Frequency of visiting stores, % | ||||||
| Never | 13.3 | 32.5 ** | 14.7 | 34.8 ** | 15.7 | 38.4 ** |
| Sometimes | 54.5 | 50.9 | 55.9 | 50.8 | 56.9 | 48.4 |
| Frequently-very frequently | 32.2 | 16.6 | 29.4 | 14.4 | 27.4 | 13.2 |
| Exposure to online ads for cigarettes, % | ||||||
| Never | 33.5 | 50.8 ** | 38.1 | 54.6 ** | 39.2 | 57.8 ** |
| Sometimes | 55.2 | 44.6 | 52.2 | 41.5 | 51.2 | 38.8 |
| Frequently-very frequently | 11.3 | 4.6 | 9.7 | 3.9 | 9.6 | 3.4 |
| Exposure to online ads for e-cigarettes, % | ||||||
| Never | 29.5 | 39.4 ** | 35.4 | 44.3 ** | 41.6 | 51.9 ** |
| Sometimes | 52.8 | 51.8 | 50.9 | 49.5 | 46.0 | 44.0 |
| Frequently-very frequently | 17.7 | 8.8 | 13.7 | 6.2 | 12.4 | 4.1 |
| Family smoke, % | 45.6 | 36.6 ** | 39.3 | 33.4 * | 37.3 | 29.7 * |
| Friends smoke, % | 58.8 | 47.1 ** | 47.9 | 40.7 ** | 41.5 | 35.7 * |
| Family uses e-cigarettes, % | 24.3 | 18.6 ** | 18.9 | 15.3 * | 10.4 | 10.2 |
| Friends use e-cigarettes, % | 67.1 | 59.5 ** | 58.4 | 52.1 * | 43.9 | 38.9 * |
| Current smoker, % | 10.2 | 3.1 ** | - | - | - | - |
| Current e-cigarette user, % | 31.3 | 14.1 ** | 16.1 | 6.5 ** | - | - |
| Alcohol use, % | 46.9 | 38.5 ** | 31.3 | 29.8 | 20.1 | 18.5 |
| Marihuana use (ever), % | 11.5 | 8.3 * | 1.7 | 1.0 | 0.8 | 0.5 |
| Perceived harm from cigarette use (disease), % | ||||||
| I don’t know/ it won’t happen/unlikely | 7.9 | 7.5 | 7.5 | 6.7 | 7.8 | 6.6 |
| Likely/very likely | 53.4 | 55.7 | 51.8 | 55.2 | 48.4 | 52.7 |
| Surely | 38.7 | 36.7 | 40.7 | 38.1 | 43.8 | 40.7 |
| Perceived addictiveness of cigarettes, % | 71.2 | 67.7 * | 74.8 | 68.8 * | 74.8 | 67.8 * |
| Perceived harm from e-cigarette use (disease), % | ||||||
| I don’t know/ it won’t happen/unlikely | 27.5 | 16.3 ** | 25.1 | 14.7 ** | 22.6 | 12.6 ** |
| Likely/very likely | 58.6 | 67.8 | 58.8 | 68.6 | 57.4 | 67.6 |
| Surely | 13.9 | 15.9 | 16.1 | 16.7 | 20.0 | 19.8 |
| Perceived addictiveness of e-cigarettes, % | 61.1 | 65.0 * | 63.1 | 65.9 | 64.8 | 67.2 |
| Susceptibility to smoke, % | 55.4 | 50.1 * | 38.3 | 38.1 | 30.5 | 26.1 * |
| Susceptibility to use e-cigarettes, % | 72.6 | 63.4 ** | 60.5 | 54.2 * | 43.8 | 34.1 ** |
P -values from Chi2 test for categorical variables and t-test for continuous variables
*
p-value <0.050,
**
p-value <0.001