Table 1.
Basic characteristics of the participants (n = 140,782).
| Variables | n | % |
|---|---|---|
| Sex | ||
| Boys | 67,945 | 48.26 |
| Girls | 72,837 | 51.74 |
| Age | 14.76 ± 1.44 | |
| Grade | ||
| 7th | 41,229 | 29.29 |
| 8th | 34,602 | 24.58 |
| 9th | 22,874 | 16.25 |
| 10th | 23,067 | 16.38 |
| 11th | 144,397 | 10.23 |
| 12th | 4,613 | 3.27 |
| Residence | ||
| Urban | 72,813 | 51.72 |
| Rural | 67,969 | 48.28 |
| Myopia | ||
| Yes | 82,637 | 58.70 |
| No | 58,145 | 41.30 |
| Boarder | ||
| Yes | 73,204 | 52.00 |
| No | 67,578 | 48.00 |
| Sleep quality | ||
| Good | 106,527 | 75.67 |
| Bad | 34,255 | 24.33 |
| Exercise time | ||
| ≤2 h | 63,613 | 45.19 |
| >2 h | 77,169 | 54.81 |
| Screen time | ||
| ≤2 h | 30,034 | 21.33 |
| >2 h | 63,374 | 78.67 |
| IA | ||
| PIU | 22,978 | 16.32 |
| NIU | 117,804 | 83.68 |
| Depression | ||
| Normal | 98,316 | 69.84 |
| Abnormal | 42,466 | 30.16 |
| Anxiety | ||
| Normal | 90,142 | 64.03 |
| Abnormal | 50,640 | 35.97 |
| Stress | ||
| Normal | 114,316 | 81.20 |
| Abnormal | 26,466 | 18.80 |
NIU, Normal Internet use (YDQ score ≤ 4 points); PIU, Problematic Internet use (YDQ score ≥ 5 points).