Table 1

Background characteristics of the study participants

CharacteristicsTotalMaleFemalep Value†
Age (years)15.15±0.01915.18±0.03915.12±0.0400.443
Height (cm)165.42±0.140170.23±0.113160.08±0.045<0.001***
Weight (kg)56.51±0.13760.77±0.13651.79±0.071<0.001***
City size
 Large39 177 (53.5)19 830 (53.6)19 347 (53.4)
 Medium29 365 (42.5)14 488 (42.4)14 877 (42.6)
 Small7101 (4.0)3555 (4.0)3546 (4.0)0.469
Grade in school
 Middle first12 728 (16.0)6548 (15.8)6180 (16.1)
 Middle second12 903 (16.7)6413 (16.4)6490 (17.0)
 Middle third12 843 (16.9)6589 (16.9)6254 (16.9)
 High first12 569 (17.2)6386 (17.3)6183 (17.1)
 High second12 508 (16.7)5954 (16.8)6554 (16.5)
 High third12 092 (16.6)5983 (16.7)6109 (16.4)0.941
School type
 Middle school38 474 (49.5)19 550 (49.1)18 924 (50.0)
 General high school27 303 (38.8)13 971 (38.8)13 332 (38.7)
 Vocational high school9866 (11.7)4352 (12.1)5514 (11.3)0.853
Family economic level
 High4777 (6.7)3165 (8.6)1612 (4.5)
 Middle high17 654 (24.1)9401 (25.1)8253 (22.9)
 Average35 762 (46.8)16 929 (44.4)18 833 (49.6)
 Middle low13 549 (17.5)6336 (16.6)7213 (18.4)
 Low3901 (5.0)2042 (5.3)1859 (4.6)<0.001***
Stress
 No32 117 (42.0)13 547 (35.8)18 570 (49.0)
 Yes43 526 (58.0)24 326 (64.2)19 200 (51.0)<0.001***
Family live together
 Yes71 859 (95.7)35 886 (95.3)35 973 (96.1)
 No3784 (4.3)1987 (4.7)1797 (3.9)0.008**
Depression (recent 12 month)
 No50 482 (67.2)27 266 (72.0)23 216 (61.8)
 Yes25 161 (32.8)10 607 (28.0)14 554 (38.2)<0.001***
Total75 643 (100.0)37 873 (50.1)37 770 (49.9)
  • **p<0.01, ***p<0.001.

  • †By unpaired t test and χ2 test.