Cases | Controls | |
Gender, n (%) | ||
Male | 37 (40) | 37 (40) |
Female | 55 (60) | 55 (60) |
Age in years, mean (range) | 14.8 (13–16) | 15.1 (13–16) |
School year, n (%) | ||
S1 | 1 (1) | 1 (1) |
S2 | 29 (32) | 29 (32) |
S3 | 28 (30) | 27 (29)* |
S4 | 34 (37) | 35 (38)* |
Social deprivation score, mean (SD) | 4.6 (1.6) | 4.2 (1.5) |
There were no substantial or statistically significant differences between cases and controls on the variables above. *One control for a case in S3 had entered S4 by the time of the interview.