(A) Demographic and smoking-related characteristics of all randomised participants (n = 1449). (B) Demographic characteristics of final sample of non-smokers and non-users of e-cigarettes (n = 1057)
| A | |||||
| E-cigarette adverts (n=714) | Control adverts (n=735) | Test statistic | P values | Total (n=1449) | |
| Age - M (SD) | 13.71 (1.40) | 13.73 (1.33) | 0.235 | 0.815 | 13.72 (1.37) |
| Gender—male % (n) | 48.5 (346) | 50.1 (368) | 0.933 | 0.334 | 49.3 (714) |
| Ethnicity—White % (n) | 74.6 (533) | 72.9 (536) | 0.557 | 0.456 | 73.8 (1069) |
| Regular cigarette use—Yes % (n) | 12.3 (88) | 12.1 (89) | 0.032 | 0.858 | 12.2 (177) |
| Cigarette experimentation—Yes % (n) | 16.1 (115) | 15.1 (111) | 0.348 | 0.555 | 15.6 (226) |
| E-cigarette awareness—Yes % (n) | 92.9 (663) | 93.9 (690) | 0.157 | 0.692 | 93.4 (1353) |
| E-cigarette use—Yes % (n) | 19.9 (142) | 21.1 (155) | 0.230 | 0.631 | 20.5 (297) |
| Cigarette use first in dual use—% (n) | 8.7 (62) | 7.9 (58) | 0.003 | 0.956 | 8.3 (120) |
| E-cigarette use first in dual use—% (n) | 8.3 (59) | 7.6 (56) | 0.003 | 0.956 | 7.9 (115) |