From: Changes in quality of life among Norwegian school children: a six-month follow-up study
 |  | Baseline | Six-month follow-up |
---|---|---|---|
Grade | Age (years) | n | n |
4th | 8–10 | 505 | 490 |
6th | 10–12 | 462 | 447 |
8th | 12–14 | 492 | 383 |
10th | 14–16 | 538 | 501 |
Total | 8–16 | 1997 | 1821 |