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Table 3 Distribution of sleep quality according to general characteristics and serum vitamin D levels

From: The relationship between serum vitamin D levels and sleep quality in fixed day indoor field workers in the electronics manufacturing industry in Korea

Variables

 

PSQI scorea

P valueb

<6

≥6

N

%

N

%

Total

 

1153

(78.3)

319

(21.7)

 

Vitamin D,

≥10

834

(80.2)

206

(19.8)

0.007

ng/mL

<10

319

(73.8)

113

(26.2)

 

Age, years

≥30

667

(82.0)

146

(18.0)

<0.001

<30

486

(73.7)

173

(26.3)

 

Sex

Male

940

(79.8)

238

(20.2)

0.006

Female

213

(72.4)

81

(27.6)

 

Regular exercise, times per week

≥3

422

(78.9)

113

(21.1)

0.699

<3

731

(78.0)

206

(22.0)

 

Smoking

Current

329

(76.9)

99

(23.1)

0.384

Never/former

824

(78.9)

220

(21.1)

 

Risky drinkingc

Yes

287

(74.7)

97

(25.3)

0.052

No

866

(79.6)

222

(20.4)

 

Body mass index, kg/m2

<25

737

(77.7)

211

(22.3)

0.463

≥25

416

(79.4)

108

(21.7)

 

Marital status

Married

638

(82.4)

136

(17.6)

<0.001

Unmarried

515

(73.8)

183

(26.2)

 

Education level

≥College

805

(81.0)

189

(19.0)

<0.001

≤High school

348

(72.8)

130

(27.2)

 

Job tenure, years

<5

358

(76.5)

110

(23.5)

0.037

5–9

289

(75.5)

94

(24.5)

 

≥10

506

(81.5)

115

(18.5)

 

Job stress

Low

962

(80.5)

225

(19.5)

<0.001

High

227

(70.7)

94

(29.3)

 

Test seasond

Spring

243

(81.0)

57

(19.0)

0.257

Summer

355

(77.9)

101

(22.1)

 

Autumn

119

(79.3)

31

(20.7)

 

Winter

436

(77.0)

130

(23.0)

 
  1. aPittsburgh Sleep Quality Index
  2. bComparison made using the chi-square test
  3. cRisky drinking: 2 or more times per week and 7 (females: 5) or more drinks per drinking session
  4. dSpring, March–May; summer, June–August; autumn, September–November; winter, December–February
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Annals of Occupational and Environmental Medicine

ISSN: 2052-4374

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