Table 1 Characteristics of the study population
|  | Life-time self-harm behaviour | Overall (n = 1883) | |
|---|---|---|---|
|  | No (n = 1224) | Yes (n = 659) | |
Age | |||
 Mean (SD) | 12.1 (2.76) | 12.5 (2.41) | 12.3 (2.65) |
 Median [Min, Max] | 12.0 [8.00, 18.0] | 13.0 [8.00, 18.0] | 12.0 [8.00, 18.0] |
 Missing | 32 (2.6%) | 7 (1.1%) | 39 (2.1%) |
Grade | |||
 Primary School | 679 (55.5%) | 297 (45.1%) | 976 (51.8%) |
 Junior High School | 332 (27.1%) | 287 (43.6%) | 619 (32.9%) |
 Senior High School | 210 (17.2%) | 75 (11.4%) | 285 (15.1%) |
 Missing | 3 (0.2%) | 0 (0%) | 3 (0.2%) |
Sex | |||
 Boys | 613 (50.1%) | 280 (42.5%) | 893 (47.4%) |
 Girls | 553 (45.2%) | 354 (53.7%) | 907 (48.2%) |
 Missing | 58 (4.7%) | 25 (3.8%) | 83 (4.4%) |
Ethnicity | |||
 Han-people | 930 (76.0%) | 518 (78.6%) | 1448 (76.9%) |
 Minorities | 196 (16.0%) | 91 (13.8%) | 287 (15.2%) |
 Missing | 98 (8.0%) | 50 (7.6%) | 148 (7.9%) |
Financial difficulties | |||
 No | 537 (43.9%) | 370 (56.1%) | 907 (48.2%) |
 Yes | 105 (8.6%) | 90 (13.7%) | 195 (10.4%) |
 Missing | 582 (47.5%) | 199 (30.2%) | 781 (41.5%) |
Family support | |||
 No | 435 (35.5%) | 276 (41.9%) | 711 (37.8%) |
 Yes | 779 (63.6%) | 376 (57.1%) | 1155 (61.3%) |
 Missing | 10 (0.8%) | 7 (1.1%) | 17 (0.9%) |
Adverse life events | |||
 No | 472 (38.6%) | 206 (31.3%) | 678 (36.0%) |
 Yes | 344 (28.1%) | 364 (55.2%) | 708 (37.6%) |
 Missing | 408 (33.3%) | 89 (13.5%) | 497 (26.4%) |