Relationship between the school bag weight and back pain for more than 15 days
| Variable | Back pain n (%) | OR (CI 95%) | |
|---|---|---|---|
| No | Yes | ||
| School bag weight | |||
| First quartile | 248 (23.9) | 83 (22.8) | 1 |
| Second quartile | 278 (26.8) | 87 (23.9) | 1.0 (0.7 to 1.4) |
| Third quartile | 258 (24.8) | 85 (23.4) | 1.1 (0.7 to 1.5) |
| Fourth quartile | 255 (24.5) | 109 (29.9) | 1.5 (1.1 to 2.1) |
| Body mass index | |||
| First quartile | 268 (25.8) | 87 (23.9) | 1 |
| Second quartile | 264 (25.4) | 82 (22.5) | 0.8 (0.6 to 1.2) |
| Third quartile | 257 (24.7) | 96 (26.4) | 1.0 (0.7 to 1.4) |
| Fourth quartile | 250 (24.1) | 99 (27.2) | 1.1 (0.8 to 1.5) |
| Perform some type of sports activity | |||
| No | 472 (45.7) | 181 (49.7) | 1 |
| Yes | 561 (54.3) | 183 (50.3) | 1.0 (0.8 to 1.3) |
| Sex | |||
| Boy | 528 (50.8) | 145 (39.8) | 1 |
| Girl | 511 (49.2) | 219 (60.2) | 1.6 (1.3 to 2.1) |
| Age (continuous variable) | – | 1.2 (1.1 to 1.3) | |