Table 2 Relationship between various risk exposures and sleep disturbance

Physical risk factors

 Unexposed

4348

61.1

4234

97.4

114

2.6

<0.001

 Exposed

2763

38.9

2642

95.6

121

4.4

Vibration

 Unexposed

5324

74.9

5158

96.9

166

3.1

0.127

 Exposed

1786

25.1

1717

96.1

69

3.9

Noise

 Unexposed

5288

74.4

5131

97.0

157

3.0

0.005

 Exposed

1823

25.6

1744

95.7

79

4.3

High temperature

 Unexposed

5671

79.8

5520

97.3

151

2.7

<0.001

 Exposed

1441

20.2

1356

94.1

85

5.9

Low temperature

 Unexposed

6356

89.4

6164

97.0

192

3.0

<0.001

 Exposed

755

10.6

711

94.2

44

5.8

Chemical risk factors

 Unexposed

5484

77.1

5322

97.0

162

3.0

0.002

 Exposed

1627

22.9

1553

95.5

74

4.5

Mist, dust, or fumes

 Unexposed

5756

81.0

5579

96.9

177

3.1

0.025

 Exposed

1354

19.0

1296

95.7

58

4.3

Organic solvents

 Unexposed

6645

93.4

6437

96.9

208

3.1

0.001

 Exposed

466

6.6

438

94.0

28

6.0

Chemical agents

 Unexposed

6612

93.0

6406

96.9

206

3.1

0.001

 Exposed

500

7.0

470

94.0

30

6.0

Biological risk factors

Infectious agents

 Unexposed

6803

95.7

6590

96.9

213

3.1

<0.001

 Exposed

308

4.3

285

92.5

23

7.5

Psychosocial risk factors

High job demand

 Low

5332

75.0

5224

98.0

108

2.0

<0.001

 High

1779

25.0

1651

92.8

128

7.2

Insufficient job control

 Low

4118

57.9

3972

96.5

146

3.5

0.211

 High

2993

42.1

2903

97.0

90

3.0

Inadequate social support

 Low

3752

52.7

3650

97.3

102

2.7

0.003

 High

3360

47.3

3226

96.0

134

4.0

Job insecurity

 Low

2963

41.8

2871

96.9

92

3.1

0.435

 High

4127

58.2

3985

96.6

142

3.4

Lack of reward

 Low

4265

60.1

4158

97.5

107

2.5

<0.001

 High

2831

39.9

2702

95.4

129

4.6