Demographic characteristics | N | Prevalence (%) | p-value | OR (95% CI) |
---|---|---|---|---|
Gender | ||||
 Female | 5250 | 37.3 | – | 1 |
 Male | 4881 | 34.7 | 0.006 | 0.893 (0.823–0.968) |
Age |  |  | < 0.001a |  |
 13 | 2308 | 23.6 | – | 1 |
 14 | 2251 | 38.2 | < 0.001 | 2.000 (1.759–2.274) |
 15 | 1663 | 38.9 | < 0.001 | 2.060 (1.795–2.364) |
 16 | 1631 | 41.3 | < 0.001 | 2.278 (1.985–2.614) |
 17 | 1120 | 37.5 | < 0.001 | 1.941 (1.663–2.265) |
 18 | 1158 | 43.4 | < 0.001 | 2.484 (2.137–2.888) |
Being only child | ||||
 No | 4547 | 38.0 | – | 1 |
 Yes | 5584 | 34.4 | < 0.001 | 0.854 (0.787–0.927) |
Household registration | ||||
 Rural | 5353 | 38.3 | – | 1 |
 Urban | 4778 | 33.4 | < 0.001 | 0.809 (0.746–0.878) |
Family economic status | ||||
 Good | 1514 | 33.4 | – | 1 |
 Middle | 7111 | 34.1 | 0.597 | 1.032 (0.918–1.161) |
 Poor | 1506 | 47.5 | < 0.001 | 1.805 (1.559–2.092) |