Table 1 The distribution of five types of WPV by demographic and occupational characteristics

Gender

 Male

866(10.8)

1629(20.4)

877(11.0)

147(1.8)

85(1.1)

 Female

6705(5.9)

26,918(23.6)

11,423(10.0)

2450(2.1)

1274(1.1)

 χ²

316.16

42.71

7.69

3.39

0.19

 P value

<0.001

<0.001

<0.001

0.066

0.665

Age group(yr)

 < 30

2881(7.4)

9106(23.4)

3498(9.0)

1238(3.2)

658(1.7)

 30–39

3696(6.1)

14,583(23.9)

6428(10.5)

1084(1.8)

568(0.9)

 ≥ 40

994(4.5)

4858(21.7)

2374(10.6)

275(1.2)

133(0.6)

 χ²

218.69

43.03

71.22

331.78

191.87

 P value

<0.001

<0.001

<0.001

<0.001

<0.001

Marital status

 Married or cohabitang

4558(5.4)

19,116(22.7)

8490(10.1)

1318(1.6)

701(0.8)

 Separated, widowed, or divorced

210(7.0)

802(26.7)

385(12.8)

88(2.9)

45(1.5)

 Never married

2803(8.0)

8629(24.7)

3425(9.8)

1191(3.4)

613(1.8)

 χ²

293.86

74.86

27.45

413.81

195.42

 P value

<0.001

<0.001

<0.001

<0.001

<0.001

Education level

 Master degree or above

410(8.0)

1297(25.2)

652(12.7)

120(2.3)

55(1.1)

 Bachelor degree

6568(6.2)

25,169(23.6)

10,749(10.1)

2248(2.1)

1192(1.1)

 Associate degree or below

593(5.6)

2081(19.6)

899(8.5)

229(2.7)

112(1.1)

 χ²

35.11

99.01

69.26

1.24

0.46

 P value

<0.001

<0.001

<0.001

0.539

0.796

Occupational variables

Professional title

 Senior

329(5.6)

1339(22.6)

770(13.0)

82(1.4)

35(0.6)

 Intermediate

3010(5.7)

12,834(24.2)

5778(10.9)

883(1.7)

462(0.9)

 Primary

4232(6.7)

14,374(22.7)

5752(9.1)

1632(2.6)

862(1.4)

 χ²

53.50

40.78

166.49

130.80

77.83

 P value

<0.001

<0.001

<0.001

<0.001

<0.001

Work schedule

 Shift

6491(6.8)

23,359(24.4)

10,030(10.5)

2208(2.3)

1163(1.2)

 Non-shift

1080(4.1)

5188(19.5)

2270(8.5)

389(1.5)

196(0.7)

 χ²

268.87

287.49

89.80

72.44

43.89

 P value

<0.001

<0.001

<0.001

<0.001

<0.001

Weekly working hours

 ≥ 50 h

1293(7.3)

4229(24.0)

1979(11.2)

447(2.5)

248(1.4)

 40–49 h

4482(6.1)

17,817(24.1)

7412(10.0)

1565(2.1)

791(1.1)

 ≤ 39 h

1796(5.8)

6501(21.1)

2909(9.5)

585(1.9)

320(1.0)

 χ²

48.75

114.16

39.57

21.91

16.65

 P value

<0.001

<0.001

<0.001

<0.001

<0.001