Stage 1‡ | Stages 1 and 2 | Risk reduction* | P value* | Stages 1, 2 and 3 | Risk reduction† | P value† | ||
n (%) | n (%) | n (%) | n (%) | n (%) | – | |||
1519 (21.3) | 1173 (16.5) | 347 (4.8) | 788 (11.1) | 731 (10.3) | ||||
School category | N (%) | % (95% CI) | % (95% CI) | % (95% CI) | – | % (95% CI) | % (95% CI) | |
Comprehensive, non-fee paying | 6350 | 20.6 (19.6 to 21.6) | 15.4 (14.5 to 16.3) | 5.3 (4.7 to 5.8) | – | 10.4 (9.7 to 11.2) | 10.2 (9.5 to 11.0) | – |
Private, fee paying | 661 | 22.7 (19.7 to 26.0) | 21.5 (18.5 to 24.8) | 1.2 (0.6 to 2.4) | <0.001 | 14.5 (12.0 to 17.4) | 8.2 (6.3 to 10.5) | 0.07 |
Alternative education providers | 118 | 50.8 (41.9 to 59.7) | 47.5 (38.7 to 56.4) | 3.4 (1.3 to 8.7) | 0.27 | 27.1 (19.9 to 35.8) | 23.7 (16.9 to 32.3) | <0.001 |
Ethnicity | ||||||||
White British | 4705 | 15.8 (14.8 to 16.8) | 11.6 (10.7 to 12.5) | 4.2 (3.6 to 4.8) | – | 6.9 (6.2 to 7.6) | 8.9 (8.1 to 9.7) | – |
Non-white British | 542 | 26.7 (23.3 to 30.5) | 21.3 (18.2 to 24.9) | 5.4 (3.8 to 7.6) | 0.21 | 14.0 (11.4 to 17.1) | 12.8 (10.3 to 15.8) | 0.01 |
Unknown | 1503 | 35.7 (33.4 to 38.0) | 29.0 (26.9 to 31.2) | 6.7 (5.6 to 8.0) | <0.001 | 22.3 (20.4 to 24.3) | 13.4 (11.8 to 15.1) | <0.001 |
Deprivation | ||||||||
Least deprived | 1279 | 14.2 (12.4 to 16.1) | 11.9 (10.3 to 13.7) | 2.3 (1.6 to 3.3) | – | 8.4 (7.0 to 10.0) | 5.8 (4.7 to 7.2) | – |
Quintile 2 | 1324 | 14.9 (13.1 to 16.8) | 11.2 (9.7 to 13.0) | 3.6 (2.8 to 4.8) | 0.04 | 7.4 (6.1 to 8.9) | 7.5 (6.2 to 9.0) | 0.08 |
Quintile 3 | 1334 | 19.8 (17.8 to 22.0) | 14.9 (13.1 to 16.9) | 4.9 (3.9 to 6.2) | <0.001 | 9.3 (7.9 to 10.9) | 10.5 (9.0 to 12.3) | <0.001 |
Quintile 4 | 1305 | 27.1 (24.8 to 29.5) | 20.8 (18.8 to 23.1) | 6.2 (5.1 to 7.6) | <0.001 | 13.8 (12.1 to 15.7) | 13.3 (11.6 to 15.1) | <0.001 |
Most deprived | 1347 | 29.8 (27.4 to 32.2) | 22.4 (20.3 to 24.6) | 7.4 (6.1 to 8.9) | <0.001 | 16.0 (14.2 to 18.0) | 13.8 (12.1 to 15.7) | <0.001 |
Unknown | 24.2 (18.5 to 30.9) | 22.0 (16.6 to 28.5) | 12.6 (8.6 to 18.2) | 0.93 | 12.6 (8.5 to 18.3) | 11.5 (7.6 to 17.1) | 0.02 |
*Risk difference for stages 1 and 2 compared with stage 1; p value for comparison with risk difference in baseline group.
†Risk difference for stages 1, 2 and 3 compared with stage 1; p value for comparison with risk difference in baseline group.
‡Stage 1: parental written consent only; stage 2: schools-based procedures (parental verbal consent and adolescent self-consent; stage 3: community settings (catch-up clinics and family practices).