Table 1 Sample characteristics by depressive symptoms at T3 (N = 2,993)

Sex, n (%)

7.20

 < 0.01

 Male

1,007(34.4)

839(83.3)

168(16.7)

 Female

1,926(65.7)

1,675(87.0)

251(13.0)

Age in years, Mean (SD)

19.8(1.3)

19.8(1.2)

19.9(1.4)

− 1.57

0.12

Ethnicity

0.01

1.00

 Han

1,267(43.2)

1,086(85.7)

181(14.3)

 Tibetan and other minorities, n (%)

1,666(56.8)

1,428(85.7)

238(14.3)

Place of origin

0.15

0.70

 Urban

852(29.0)

727(85.3)

125(14.7)

 Rural

2,081(71.0)

1,787(85.9)

294(14.1)

HSS, n (%)

 Excellent or very good

478(16.3)

412(86.2)

66(13.8)

14.17

 < 0.001

 Good

1,540(52.5)

1,350(87.7)

190(12.3)

 Fair or poor

915(31.2)

752(82.2)

163(17.8)

Father’s education level, n (%)

4.38

0.49

 Primary school or below

1,230(41.9)

1,040(84.6)

190(15.4)

 Junior high school

723(24.7)

627(86.7)

96(13.3)

 High school/technical secondary school

437(14.9)

376(86.0)

61(14.0)

 Junior college

178(6.1)

155(87.1)

23(25.4)

 University or above

241(8.2)

213(88.4)

28(11.6)

 Unknown

124(4.2)

103(83.1)

21(16.9)

Mother’s education level, n (%)

15.48

 < 0.01

 Primary school or below

1,550(52.8)

1,324(85.4)

226(14.6)

 Junior high school

599(20.4)

536(89.5)

63(10.5)

 High school/technical secondary school

347(11.8)

284(81.8)

63(18.2)

 Junior college

148(5.0)

131(88.5)

17(11.5)

 University or above

168(5.7)

142(84.5)

26(15.5)

 Unknown

121(4.1)

97(80.2)

24(19.8)

Smoking, n (%)

1.72

0.19

 No

2,629(89.6)

2,261(86.0)

368(14.0)

 Yes

304(10.4)

253(83.2)

51(16.8)

Drinking, n (%)

5.53

 < 0.05

 No

2,542(86.7)

2,194(86.3)

348(13.7)

 Yes

391(13.3)

320(81.8)

71(18.2)