Table 1.
General characteristics of study observations (2015–2017).
| Variable | Boys | p-Value | Girls | p-Value | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total | Stress | Non-Stress | Total | Stress | Non-Stress | |||||||||
| n | (%) | n | (%) | n | (%) | n | (%) | n | (%) | n | (%) | |||
| Number of days of intense physical activity per week | <0.0001 | <0.0001 | ||||||||||||
| More than 5 days a week | 21,876 | 24.3 | 15,161 | 69.3 | 6715 | 30.7 | 7065 | 8.8 | 5779 | 81.8 | 1286 | 18.2 | ||
| 4 days a week | 8423 | 9.4 | 6043 | 71.7 | 2380 | 28.3 | 4004 | 5.0 | 3291 | 82.2 | 713 | 17.8 | ||
| 3 days a week | 16,197 | 18.0 | 11,739 | 72.5 | 4458 | 27.5 | 10,182 | 12.7 | 8370 | 82.2 | 1812 | 17.8 | ||
| 2 days a week | 17,154 | 19.1 | 12,954 | 75.5 | 4200 | 24.5 | 14,471 | 18.0 | 12,161 | 84.0 | 2310 | 16.0 | ||
| 1 days a week | 14,123 | 15.7 | 10,749 | 76.1 | 3374 | 23.9 | 18,610 | 23.2 | 15,814 | 85.0 | 2796 | 15.0 | ||
| Non-physical activity | 12,268 | 13.6 | 9302 | 75.8 | 2966 | 24.2 | 25,986 | 32.4 | 22,418 | 86.3 | 3568 | 13.7 | ||
| Age | <0.0001 | <0.0001 | ||||||||||||
| 14 (middle school 1) | 15,558 | 17.3 | 10,420 | 67.0 | 5138 | 33.0 | 14,266 | 17.8 | 11,221 | 78.7 | 3045 | 21.3 | ||
| 15 (middle school 2) | 16,044 | 17.8 | 11,385 | 71.0 | 4659 | 29.0 | 14,443 | 18.0 | 11,888 | 82.3 | 2555 | 17.7 | ||
| 16 (middle school 3) | 16,420 | 18.2 | 11,823 | 72.0 | 4597 | 28.0 | 15,153 | 18.9 | 12,516 | 82.6 | 2637 | 17.4 | ||
| 17 (high school 1) | 14,356 | 15.9 | 10,755 | 74.9 | 3601 | 25.1 | 12,644 | 15.7 | 10,948 | 86.6 | 1696 | 13.4 | ||
| 18 (high school 2) | 14,814 | 16.5 | 11,581 | 78.2 | 3233 | 21.8 | 12,709 | 15.8 | 11,335 | 89.2 | 1374 | 10.8 | ||
| 19 (high school 3) | 12,849 | 14.3 | 9984 | 77.7 | 2865 | 22.3 | 11,103 | 13.8 | 9925 | 89.4 | 1178 | 10.6 | ||
| Household income | <0.0001 | <0.0001 | ||||||||||||
| High | 10,349 | 11.5 | 6579 | 63.6 | 3770 | 36.4 | 5888 | 7.3 | 4325 | 73.5 | 1563 | 26.6 | ||
| Medium-high | 25,118 | 27.9 | 17,845 | 71.0 | 7273 | 29.0 | 20,807 | 25.9 | 16,997 | 81.7 | 3810 | 18.3 | ||
| Medium | 40,329 | 44.8 | 29,882 | 74.1 | 10,447 | 25.9 | 40,262 | 50.1 | 34,445 | 85.6 | 5817 | 14.5 | ||
| Medium-low | 11,335 | 12.6 | 9258 | 81.7 | 2077 | 18.3 | 11,046 | 13.8 | 9957 | 90.1 | 1089 | 9.9 | ||
| Low | 2910 | 3.2 | 2384 | 81.9 | 526 | 18.1 | 2315 | 2.9 | 2109 | 91.1 | 206 | 8.9 | ||
| Residence type | <0.0001 | <0.0001 | ||||||||||||
| Live with family | 85,770 | 95.3 | 62,738 | 73.2 | 23,032 | 26.9 | 77,208 | 96.1 | 65,119 | 84.3 | 12,089 | 15.7 | ||
| Live with relative | 857 | 1.0 | 633 | 73.9 | 224 | 26.1 | 621 | 0.8 | 553 | 89.1 | 68 | 11.0 | ||
| Accommodation, dormitory | 2846 | 3.2 | 2203 | 77.4 | 643 | 22.6 | 2131 | 2.7 | 1885 | 88.5 | 246 | 11.5 | ||
| Childcare facility | 568 | 0.6 | 374 | 65.9 | 194 | 34.2 | 358 | 0.5 | 276 | 77.1 | 82 | 22.9 | ||
| Number of days of weight training per week | <0.0001 | <0.0001 | ||||||||||||
| More than 5 days a week | 14,323 | 15.9 | 10,119 | 70.7 | 4204 | 29.4 | 3513 | 4.4 | 2889 | 82.2 | 624 | 17.8 | ||
| 4 days a week | 4766 | 5.3 | 3420 | 71.8 | 1346 | 28.2 | 1539 | 1.9 | 1252 | 81.4 | 287 | 18.7 | ||
| 3 days a week | 10,514 | 11.7 | 7496 | 71.3 | 3018 | 28.7 | 4023 | 5.0 | 3298 | 82.0 | 725 | 18.0 | ||
| 2 days a week | 13,048 | 14.5 | 9529 | 73.0 | 3519 | 27.0 | 6803 | 8.5 | 5615 | 82.5 | 1188 | 17.5 | ||
| 1 days a week | 17,112 | 19.0 | 12,596 | 73.6 | 4516 | 26.4 | 13,859 | 17.3 | 11,460 | 82.7 | 2399 | 17.3 | ||
| Non-weight training | 30,278 | 33.6 | 22,788 | 75.3 | 7490 | 24.7 | 50,581 | 63.0 | 43,319 | 85.6 | 7262 | 14.4 | ||
| Time spent sitting and studying on a weekday (hours) | <0.0001 | <0.0001 | ||||||||||||
| <8 | 45,158 | 50.2 | 32,410 | 71.8 | 12,748 | 28.2 | 27,262 | 33.9 | 22,703 | 83.3 | 4559 | 16.7 | ||
| 8 ≤ n < 12 | 19,429 | 21.6 | 14,061 | 72.4 | 5368 | 27.6 | 20,195 | 25.1 | 16,902 | 83.7 | 3293 | 16.3 | ||
| 12 ≤ n < 16 | 15,512 | 17.2 | 11,702 | 75.4 | 3810 | 24.6 | 19,300 | 24.0 | 16,371 | 84.8 | 2929 | 15.2 | ||
| 16 ≤ n < 20 | 9942 | 11.0 | 7775 | 78.2 | 2167 | 21.8 | 13,561 | 16.9 | 11,857 | 87.4 | 1704 | 12.6 | ||
| Grade | <0.0001 | <0.0001 | ||||||||||||
| High | 12,344 | 13.7 | 8349 | 67.6 | 3995 | 32.4 | 8259 | 10.3 | 6,430 | 77.9 | 1829 | 22.2 | ||
| Medium-high | 21,234 | 23.6 | 15,322 | 72.2 | 5912 | 27.8 | 20,132 | 25.1 | 16,632 | 82.6 | 3500 | 17.4 | ||
| Medium | 24,807 | 27.6 | 18,022 | 72.7 | 6785 | 27.4 | 23,508 | 29.3 | 19,858 | 84.5 | 3650 | 15.5 | ||
| Medium-low | 21,020 | 23.3 | 15,937 | 75.8 | 5083 | 24.2 | 20,047 | 25.0 | 17,459 | 87.1 | 2588 | 12.9 | ||
| Low | 10,636 | 11.8 | 8318 | 78.2 | 2318 | 21.8 | 8372 | 10.4 | 7,454 | 89.0 | 918 | 11.0 | ||
| Alcohol consumption | <0.0001 | <0.0001 | ||||||||||||
| Yes | 38,778 | 43.1 | 29,950 | 77.2 | 8828 | 22.8 | 27,254 | 33.9 | 24,137 | 88.6 | 3117 | 11.4 | ||
| No | 51,263 | 56.9 | 35,998 | 70.2 | 15,265 | 29.8 | 53,064 | 66.1 | 43,696 | 82.4 | 9368 | 17.7 | ||
| Smoking | <0.0001 | <0.0001 | ||||||||||||
| Yes | 19,837 | 22.0 | 15,544 | 78.4 | 4293 | 21.6 | 6391 | 8.0 | 5732 | 89.7 | 659 | 10.3 | ||
| No | 70,204 | 78.0 | 50,404 | 71.8 | 19,800 | 28.2 | 73,927 | 92.0 | 62,101 | 84.0 | 11,826 | 16.0 | ||
| Depression | <0.0001 | <0.0001 | ||||||||||||
| Yes | 17,592 | 19.5 | 16,102 | 91.5 | 1490 | 8.5 | 23,307 | 29.0 | 22,372 | 96.0 | 935 | 4.0 | ||
| No | 72,449 | 80.5 | 49,846 | 68.8 | 22,603 | 31.2 | 57,011 | 71.0 | 45,461 | 79.7 | 11,550 | 20.3 | ||
| Suicidal ideation | <0.0001 | <0.0001 | ||||||||||||
| Yes | 8227 | 9.1 | 7667 | 93.2 | 560 | 6.8 | 11,597 | 14.4 | 11,236 | 96.9 | 361 | 3.1 | ||
| No | 81,814 | 90.9 | 58,281 | 71.2 | 23,533 | 28.8 | 68,721 | 85.6 | 56,597 | 82.4 | 12,124 | 17.6 | ||
| Total | 90,041 | 100 | 65,948 | 73.2 | 24,093 | 26.8 | 80,318 | 100 | 67,833 | 84.5 | 12,485 | 15.5 | ||