Variable | Â | Intervention | Controls | ||
---|---|---|---|---|---|
 |  | No. | % | No. | % |
Age at start: | 13 | 0 | (0%) | 57 | (58%) |
14 | 234 | (66%) | 40 | (41%) | |
15 | 118 | (34%) | 1 | (1%) | |
Missing | 33 | Â | 4 | Â | |
Gender: | Male | 179 | (49%) | 42 | (44%) |
Female | 185 | (51%) | 53 | (56%) | |
Missing | 21 | Â | 7 | Â | |
Ethnic group | White | 358 | (93%) | 95 | (93%) |
Mixed | 11 | (3%) | 3 | (3%) | |
Asian | 6 | (2%) | 1 | (1%) | |
Black | 5 | (1%) | 0 | (0%) | |
Other | 4 | (1%) | 0 | (0%) | |
Missing | 1 | Â | 3 | Â |