Characteristics of the intervention and control groups at baseline, and in the response and non-response groups at the first post-test
| Baseline | Response group* | Non-response group | ||||||
|---|---|---|---|---|---|---|---|---|
| Intervention n=1444 | Control n=1118 | p* | Intervention n=1003 | Control n=725 | Intervention n=441 | Control n=393 | p† | |
| *χ2 Statistics; NS=p >0.05. | ||||||||
| †p Value for differences between the intervention and the control group regarding the distribution of the characteristics in the response group and the non-response group (χ2 test). | ||||||||
| ‡Differences in baseline characteristics between the intervention and the control group (χ2 test). | ||||||||
| ‡ (%) boys | 713 (49.5) | 677 (60.9) | <0.001 | 471 (47.0) | 423 (58.3) | 242 (55.3) | 254 (65.6) | NS |
| Full time job | NS | 0.006 | ||||||
| ‡ (%) yes | 1152 (79.8) | 866 (77.5) | 833 (83.1) | 586 (80.8) | 319 (72.3) | 280 (71.2) | ||
| ‡ (%) no | 248 (17.2) | 199 (17.8) | 165 (16.5) | 119 (16.4) | 83 (18.8) | 82 (20.9) | ||
| ‡ (%) unknown | 44 (3.0) | 53 (4.7) | 5 (0.5) | 20 (2.8) | 39 (8.8) | 33 (8.4) | ||
| Ethnicity | <0.001 | 0.000 | ||||||
| ‡ (%) non-Dutch | 150 (10.4) | 154 (13.8) | 104 (10.4) | 76 (10.5) | 46 (10.4) | 78 (19.8) | ||
| ‡ (%) Dutch ‡ (%) | 1252 (86.7) | 907 (81.1) | 882 (87.9) | 608 (83.9) | 370 (83.9) | 299 (76.2) | ||
| ‡ (%) unknown | 42 (2.9) | 57 (5.1) | 17 (1.7) | 41 (5.7) | 25 (5.7) | 16 (4.1) | ||
| Religion | <0.001 | 0.000 | ||||||
| ‡ (%) Christian | 414 (28.7) | 241 (21.6) | 269 (26.8) | 183 (25.2) | 145 (32.9) | 58 (14.8) | ||
| ‡ (%) non-Christian | 117 (8.1) | 121 (10.8) | 80 (8.1) | 61 (8.4) | 37 (8.4) | 60 (15.3) | ||
| ‡ (%) none | 856 (59.3) | 682 (61.0) | 631 (62.9) | 432 (59.6) | 225 (51.0) | 250 (63.6) | ||
| ‡ (%) unknown | 57 (3.9) | 74 (6.6) | 23 (2.3) | 49 (6.8) | 34 (7.7) | 25 (6.4) | ||
| Age (y) | <0.001 | 0.043 | ||||||
| ‡ (%) 10 to 13 | 641 (44.4) | 397 (35.5) | 463 (46.3) | 326 (45.0) | 178 (40.4) | 71 (18.1) | ||
| ‡ (%) 13 | 597 (46.1) | 576 (51.5) | 440 (43.9) | 339 (46.8) | 225 (51.0) | 237 (60.3) | ||
| ‡ (%) 14 | 125 (9.6) | 145 (13.0) | 90 (10.0) | 60 (8.3) | 38 (8.6) | 85 (21.6) | ||
| Smoking at baseline | NS | 0.007 | ||||||
| ‡ (%) yes | 254 (17.6) | 223 (19.9) | 172 (17.1) | 115 (15.9) | 82 (18.6) | 108 (27.5) | ||
| ‡ (%) no | 1157 (80.1) | 852 (76.2) | 821 (81.9) | 586 (80.8) | 336 (76.2) | 266 (67.7) | ||
| ‡ (%) unknown (excluded analyses) | 33 (2.3) | 43 (3.8) | 10 (1.0) | 24 (3.3) | 23 (5.2) | 19 (4.8) | ||