Table 1.
Baseline characteristics
| Variable | Entire sample (%) (n) | Intervention group (%) (n) | Control group (%) (n) |
|---|---|---|---|
| Number of pupils | (100) 9851 | (53.2) 5238 | (46.8) 4613 |
| Number of schools | (100) 126 | (52.4) 66 | (47.6) 60 |
| Grammar Schools | (100) 25 | (16.7) 11 | (23.3) 14 |
| Gender | (97.5) 9609 | ||
| Female | (46.8) 4612 | (49.3) 2520 | (46.5) 2092 |
| Male | (50.7) 4997 | (50.7) 2592 | (53.5) 2405 |
| Age | (98.6) 9710 | (53) 5151 | (47) 4559 |
| M=12.01 (SD=0.86) | M=11.98 (SD=0.84) | ||
| Number of pupils per grade | (100) 9851 | ||
| Missing in questionnaire (either grade 6 or 7) | (1.5) 156 | (0.8) 44 | (2.4) 112 |
| 6 | (49.7) 4892 | (48.9) 2559 | (50.6) 2333 |
| 7 | (48.8) 4803 | (50.3) 2635 | (47) 2168 |
| Current cigarette smokers At least once in the past 30 days |
(4.7 of 9756 valid answers) 463 | (4.1 of 5185 valid answers) 210 | (5.5 of 4571 with valid answers) 253 |
| Average days of use in the past 30 days | M=7.91 (SD=9.78) | M=8.3 (SD=9.92) | M=7.58 (SD=9.68) |
| Average number of cigarettes smoked in the past 30 days | M=42.91 (SD=105.05) | M=40.6 (SD=98.6) | M=44.83 (SD=110.28) |
| 1–2 days/average cigarettes per day (acd) | (2.4) 237/1.25 | (1.9) 99/1.33 | (3) 138/1.19 |
| 3–5 days/acd | (0.7) 67/2.12 | (0.6) 33/2.52 | (0.7) 34/1.74 |
| 6–9 days/acd | (0.5) 44/3.08 | (0.4) 23/3.04 | (0.5) 21/3.12 |
| 10–19 days/acd | (0.4) 39/5.31 | (0.4) 20/4.92 | (0.4) 19/5.71 |
| 20–29 days/acd | (0.3) 25/4.34 | (0.2) 9/3.33 | (0.4) 16/4.91 |
| All 30 days/acd | (0.5) 51/7.88 | (0.5) 26/6.88 | (0.5) 25/8.88 |
| Not in the past 30 days (=non-smokers) | (95.3) 9293 | (95.9) 4975 | (94.5) 4318 |
| I never tried smoking, not even a puff | (80.2) 7755 (n=9672 valid answers) |
(80.5) 4145 | (79.9) 3610 |
| Never smoked a cigarette (never-smokers) | (94.1 of 9748 valid answers) 9175 | (95.2) 4931 | (92.9) 4244 |
| Ex-smokers who smoked | |||
| More than once per week | (1.8) 175 | (1.4) 72 | (2.3) 103 |
| Less than once per week | (1.8) 177 | (1.5) 77 | (2.2) 100 |
| Average age of first puff (years) | |||
| 8 years or younger | (11.3) 215 | (12.6) 126 | (9.8) 89 |
| 9–10 | (20.1) 384 | (19.9) 200 | (20.3) 184 |
| 11–12 | (57.2) 1092 | (55.9) 561 | (58.6) 531 |
| 13–14 | (11.4) 218 | (11.6) 116 | (11.3) 102 |
| Intention to smoke cigarettes (0–6) (0=I am very sure that I will never smoke; 6=I believe that I will start smoking within the next month) |
0.51 | 0.49 | 0.53 |
| Do you intend to quit cigarettes? (0–3) (0=No; 3=within the next month) |
0.84 | 0.71 | 0.97 |
| Current tobacco waterpipe smokers/average days of use in the past 30 days (ad30) | (2.3) 228/M=6.73 (SD=9.2) | (2.4) 125/M=6.93 (SD=9.34) | (2.3) 103/M=6.49 (SD=9.08) |
| Current e-cigarette smokers/ad30 | (4.6) 443/M=6.25 (SD=8.61) | (4.6) 237/M=6.24 (SD=8.51) | (4.5) 206/M=6.27 (SD=8.75) |
| Current cigar or cigarillo smokers/ad30 | (0.6) 56/M=6.87 (SD=9.81) | (0.6) 33/M=7.76 (SD=9.89) | (0.5) 23/M=5.59 (SD=9.76) |
| Current chewing tobacco consumers/ad30 | (0.2) 17/M=8.56 (SD=11.1) | (0.2) 8/M=11 (SD=12.58) | (0.2) 9/M=6.39 (SD=9.83) |
| Current Marihuana smokers/ad30 | (0.8) 78/M=7.67 (SD=10.75) | (0.9) 45/M=8.22 (SD=11.27) | (0.7) 33/M=6.91 (SD=10.12) |
| Current steam stone waterpipe smokers/ad30 | (1.7) 168/M=6.13 (SD=8.59) | (1.9) 102/M=5.94 (SD=8.39) | (1.4) 66/M=6.41 (SD=8.95) |
| Current use of other tobacco product/ad30 | (0.7) 71/M=8.18 (SD=10.39) | (0.7) 35/M=10.31 (SD=11.89) | (0.8) 36/M=6.1 (SD=8.34) |
| Current use of two tobacco products | (3.6) 351 | (3.6) 187 | (3.6) 164 |
| Current use of e-cigarettes and cigarettes | (1.6) 160 | (1.5) 78 | (1.8) 82 |
| Current use of waterpipe with tobacco and cigarettes | (1.0) 101 | (1.0) 51 | (1.1) 50 |
| Ex-smokers who smoked | |||
| More than once per week | (1.8) 175 | (1.4) 72 | (2.3) 103 |
| Less than once per week | (1.8) 177 | (1.5) 77 | (2.2) 100 |
| I have at least one smoking parent | (48.6) 4595 | (47.7) 2386 | (49.7) 2209 |
| One of my best friends smokes | (15.8) 1413 | (15) 717 | (16.6) 696 |
| I have an older sibling that smokes | (15.3) 1422 | (13.7) 675 | (17.1) 747 |
| Migrational background | |||
| Both parents born in Germany | (69.6) 6721 | (66.3) 3403 | (73.3) 3318 |
| One parent born in Germany | (13.1) 1263 | (13.4) 689 | (12.7) 574 |
| No parent born in Germany | (17.3) 1670 | (20.2) 1038 | (14) 632 |
| School performance (self-reported point average) | (96) 9460 | (53) 5011 | (47) 4449 |
| M=2.44 (SD=0.79) | M=2.45 (SD=0.8) | ||
| Educational level (1–5) (1=no completed school education; 5=completed university) | |||
| Father | 3.62 | 3.58 | 3.67 |
| Mother | 3.6 | 3.57 | 3.64 |
| ‘Do you live in the same household with your parents?’ | |||
| I live with no parent | (5) 488 | (5) 262 | (4.9) 226 |
| I live with one parent | (24.5) 2408 | (23.8) 1247 | (25.1) 1161 |
| I live with both parents | (70.6) 6955 | (71.2) 3729 | (69.9) 3226 |
| Student participation rate | (69.54) 9851/14 165 | (67.33) 5238/7780 | (72.25) 4613/6385 |
| ‘I know that this survey is anonymous and what that means’. | (88.4) 8520 | (87.7) 4475 | (89.2) 4045 |
| ‘I knew that the survey would be today’. | (32.6) 3121 | (34.9) 1770 | (30) 1351 |