Table 1 Sample characteristics by depressive symptoms, smoking, drinking and gender (N = 18496).
Variables | Total, n (%) | Depressive symptoms, n (%) | Cigarette smoking, n (%) | Alcohol consumption, n (%) | CIE1,% | CIE2, % | Girls, n (%) | Boys, n (%) | P value* |
|---|---|---|---|---|---|---|---|---|---|
Total | 18496(100) | 1685(9.1) | 1636(8.8) | 4340(23.5) | 9731(52.6) | 8765(47.4) | |||
Age(year)** | 15.5 ± 1.7 | 15.6 ± 1.6 | 16.3 ± 1.4 | 15.8 ± 1.6 | 15.5 ± 1.7 | 15.4 ± 1.7 | <0.001 | ||
Cigarette smoking | 1636(8.8) | 218(13.3) | 1101(67.3) | −3.9 | 186(11.4) | 1450(88.6) | <0.001 | ||
Alcohol consumption | 4340(23.5) | 599(13.8) | 1101(25.4) | −25.9 | 1580(36.4) | 2760(63.6) | <0.001 | ||
Depressive symptoms | 1685(9.1) | 218(12.9) | 599(35.5) | 1012(60.1) | 673(39.9) | <0.001 | |||
Gender | 25.0 | 10.9 | |||||||
Girls | 9731(52.6) | 1012(10.4) | 186(1.9) | 1580(16.2) | |||||
Boys | 8765(47.4) | 673(7.7) | 1450(16.5) | 2760(31.5) | |||||
Grade | −4.1 | −2.7 | <0.001 | ||||||
7th | 3213(17.4) | 212(6.6) | 81(2.5) | 443(13.8) | 1503(46.8) | 1710(53.2) | |||
8th | 4064(22.0) | 375(9.2) | 223(5.5) | 846(20.8) | 2052(50.5) | 2012(49.5) | |||
9th | 484(2.6) | 59(12.2) | 34(7.0) | 112(23.1) | 229(47.3) | 255(52.7) | |||
10th | 5788(31.3) | 553(9.6) | 711(12.3) | 1558(26.9) | 3164(54.7) | 2624(45.3) | |||
11th | 4683(25.3) | 473(10.1) | 551(11.8) | 1312(28.0) | 2644(56.5) | 2039(43.5) | |||
12th | 264(1.4) | 13(4.9) | 36(13.6) | 69(26.1) | 139(52.7) | 125(47.3) | |||
Father’s education level | −1.1 | −0.5 | <0.001 | ||||||
Primary school or lower | 3682(19.9) | 370(10.0) | 329(8.9) | 849(23.1) | 2094(56.9) | 1588(43.1) | |||
High school | 13412(72.5) | 1149(8.6) | 1195(8.9) | 3120(23.3) | 6953(51.8) | 6459(48.2) | |||
University or higher | 1249(6.8) | 146(11.7) | 104(8.3) | 341(27.3) | 592(47.4) | 657(52.6) | |||
Missing data | 153(0.8) | ||||||||
Mother’s education level | 0.7 | 0.2 | <0.001 | ||||||
Primary school or lower | 5722(30.8) | 531(9.3) | 457(8.0) | 1271(22.2) | 3267(57.1) | 2455(42.9) | |||
High school | 11830(64.0) | 1050(8.9) | 1095(9.3) | 2813(23.8) | 6031(51.0) | 5799(49.0) | |||
University or higher | 805(4.4) | 90(11.2) | 78(9.7) | 231(28.7) | 355(44.1) | 450(55.9) | |||
Missing data | 139(0.8) | ||||||||
Living arrangement | −0.2 | 0.0 | 0.605 | ||||||
Two biological parents | 10123(54.7) | 831(8.2) | 876(8.7) | 2398(23.7) | 5293(52.3) | 4830(47.7) | |||
Only father or mother | 3036(16.4) | 355(11.7) | 276(9.1) | 721(23.7) | 1617(53.3) | 1419(46.7) | |||
Others | 5268(28.5) | 495(9.4) | 482(9.1) | 1214(23.0) | 2781(52.8) | 2487(47.2) | |||
Missing data | 69(0.4) | ||||||||
Number of brothers and sisters | 1.1 | 1.1 | <0.001 | ||||||
0 | 6751(36.5) | 602(8.9) | 653(9.7) | 1739(25.8) | 3009(44.6) | 3742(55.4) | |||
1 | 8316(45.0) | 710(8.5) | 743(8.9) | 1895(22.8) | 4589(55.2) | 3727(44.8) | |||
2 | 2395(12.9) | 246(10.3) | 162(6.8) | 474(19.8) | 1543(64.4) | 852(35.6) | |||
>=3 | 991(5.4) | 124(12.5) | 77(7.8) | 222(22.4) | 570(57.5) | 421(42.5) | |||
Missing data | 43(0.2) | ||||||||
Family economic status | −0.9 | 1.1 | <0.001 | ||||||
Above average | 1944(10.5) | 128(6.6) | 202(10.4) | 493(25.4) | 837(43.1) | 1107(56.9) | |||
Average | 10617(57.4) | 853(8.0) | 883(8.3) | 2482(23.4) | 5690(53.6) | 4927(46.4) | |||
Below average | 5857(31.7) | 700(12.0) | 548(9.4) | 1347(23.0) | 3154(53.9) | 2703(46.1) | |||
Missing data | 78(0.4) | ||||||||
Communication with parents | −8.7 | −6.2 | <0.001 | ||||||
More with father | 1418(7.7) | 124(8.7) | 146(10.3) | 347(24.5) | 680(48.0) | 738(52.0) | |||
More with mother | 5121(27.7) | 390(7.6) | 350(6.8) | 1091(21.3) | 3188(62.3) | 1933(37.7) | |||
Much with both | 4078(22.0) | 161(3.9) | 270(6.6) | 791(19.4) | 2116(51.9) | 1962(48.1) | |||
Little with both | 7760(42.0) | 1001(12.9) | 859(11.1) | 2091(26.9) | 3695(47.6) | 4065(52.4) | |||
Missing data | 119(0.6) | ||||||||
Relationship with teachers | −3.2 | 2.2 | <0.001 | ||||||
Good | 10787(58.3) | 654(6.1) | 925(8.6) | 2556(23.7) | 5659(52.5) | 5128(47.5) | |||
Average | 7024(38.0) | 816(11.6) | 632(9.0) | 1615(23.0) | 3779(53.8) | 3245(46.2) | |||
Poor | 635(3.4) | 214(33.7) | 75(11.8) | 158(24.9) | 269(42.4) | 366(57.6) | |||
Missing data | 50(0.3) | ||||||||
Relationship with classmates | −10.0 | −5.6 | <0.001 | ||||||
Good | 7374(39.9) | 394(5.3) | 579(7.9) | 1641(22.3) | 3732(50.6) | 3642(49.4) | |||
Average | 9743(52.6) | 974(10.0) | 840(8.6) | 2234(22.9) | 5424(55.7) | 4319(44.3) | |||
Poor | 1325(7.2) | 313(23.6) | 211(15.9) | 453(34.2) | 552(41.7) | 773(58.3) | |||
Missing data | 54(0.3) | ||||||||
Number of good friends | 6.1 | 7.1 | <0.001 | ||||||
0 | 386(2.1) | 133(34.5) | 39(10.1) | 84(21.8) | 169(43.8) | 217(56.2) | |||
1 | 663(3.6) | 140(21.1) | 42(6.3) | 123(18.6) | 391(59.0) | 272(41.0) | |||
2 | 1898(10.3) | 248(13.1) | 106(5.6) | 368(19.4) | 1228(64.7) | 670(35.3) | |||
>=3 | 15499(83.8) | 1155(7.5) | 1440(9.3) | 3749(24.2) | 7918(51.1) | 7581(48.9) | |||
Missing data | 50(0.3) | ||||||||
Pocket money (RMB) | −2.0 | −0.5 | 0.042 | ||||||
<200 | 13955(75.4) | 1251(9.0) | 1079(7.7) | 3006(21.5) | 7297(52.3) | 6658(47.7) | |||
200-499 | 3684(19.9) | 329(8.9) | 405(11.0) | 1049(28.5) | 1998(54.2) | 1686(45.8) | |||
>500 | 721(4.0) | 91(12.6) | 142(19.7) | 261(36.2) | 361(50.1) | 360(49.9) | |||
Missing data | 136(0.7) | ||||||||
Time doing homework | 4.6 | 1.6 | <0.001 | ||||||
<=1 | 6987(37.8) | 530(7.6) | 917(13.1) | 1920(27.5) | 3826(54.8) | 3161(45.2) | |||
2-3 | 8912(48.1) | 769(8.6) | 507(5.7) | 1799(20.2) | 3807(42.7) | 5105(57.3) | |||
>3 | 2507(13.6) | 384(15.3) | 208(8.3) | 603(24.1) | 1096(43.7) | 1411(56.3) | |||
Missing data | 90(0.5) | ||||||||
Academic pressure | 2.5 | −1.0 | <0.001 | ||||||
Above average | 7859(42.5) | 1119(14.2) | 671(8.5) | 1914(24.4) | 4349(55.3) | 3510(44.7) | |||
Average | 8109(43.8) | 409(5.0) | 612(7.5) | 1754(21.6) | 4381(54.0) | 3728(46.0) | |||
Below average | 2489(13.5) | 154(6.2) | 350(14.1) | 669(26.9) | 983(39.5) | 1506(60.5) | |||
Missing data | 39(0.2) | ||||||||
Father current smoking | 10711(57.9) | 973(9.1) | 1009(9.4) | 2652(24.8) | −0.7 | 0.3 | 5729(53.5) | 4982(46.5) | 0.006 |
Mother current smoking | 243(1.3) | 35(14.4) | 35(14.4) | 77(31.7) | −1.2 | −0.1 | 131(53.9) | 112(46.1) | 0.687 |
Father current drinking | 5392(29.2) | 572(10.6) | 532(9.9) | 1501(27.8) | −1.3 | −1.8 | 2740(50.8) | 2652(49.2) | 0.001 |
Mother current drinking | 158(0.9) | 19(12.0) | 16(10.1) | 50(31.6) | −0.5 | −0.5 | 80(50.6) | 78(49.4) | 0.610 |
