Table 4 Comparison of general demographic characteristics and hair cortisol concentration levels in Karamay, Xinjiang in 2013

Sex

 male

132

3.744 (2.363–6.298)

3.651 ± 2.071

 female

199

2.584 (1.876–3.786)

2.588 ± 1.712

Age

 20–29

52

3.037 (1.962–4.659)

3.058 ± 1.842

 30–39

131

2.792 (2.116–4.821)

3.009 ± 1.916

 40–60

148

2.868 (1.884–4.358)

2.903 ± 1.912

BMI (kg/m²)

 <18.5

11

2.687 (2.134–3.611)

2.773 ± 1.575

 18.5–23.9

174

2.804 (1.876–4.447)

2.865 ± 1.840

 24–28.0

103

2.744 (1.947–4.857)

3.038 ± 2.134

 ≥ 28

43

3.279 (2.357–4.021)

3.302 ± 1.638

Ethnicity

 Han

258

2.830 (1.906–4.540)

2.909 ± 1.930

 Uygur

43

2.933 (2.128–4.289)

2.942 ± 1.762

 Other minority

30

3.561 (2.361–5.570)

3.585 ± 1.807

Marital status

 Not married

41

3.114 (1.899–4.878)

2.962 ± 1.758

 Married

249

2.853 (2.081–4.440)

3.035 ± 1.899

 Other (divorced, widowed, remarried)

41

2.735 (1.551–4.374)

2.602 ± 2.036

Education level

 High school or below

75

2.722 (1.860–3.611)

2.666 ± 1.760

 Junior college education

210

3.022 (2.075–4.909)

3.109 ± 1.961

 College or above

46

2.887 (1.741–4.168)

2.8671.839

Family history of hypertension

 Yes

114

2.895 (1.942–4.759)

2.97 ± 1.964

 No

195

2.878 (1.957–4.1611)

2.980 ± 1.871

 Unknown

22

2.761 (1.876–4.633)

2.849 ± 1.875

Family history of coronary heart disease

 Yes

49

2.773 (1.886–5.178)

3.152 ± 1.878

 No

262

2.890 (1.966–4.275)

2.953 ± 1.906

 Unknown

20

2.354 (1.837–4.788)

2.755 ± 1.917

Family history of stroke

 Yes

49

2.669 (2.029–3.206)

2.692 ± 1.514

 No

262

2.906 (1.969–4.494)

2.999 ± 1.916

 Unknown

20

2.354 (1.850–4.902)

2.771 ± 1.897

Family history of diabetes

 Yes

59

2.773 (1.969–4.763)

3.060 ± 1.750

 No

248

2.889 (1.924–4.359)

2.946 ± 1.945

 Unknown

24

3.184 (1.945–4.788)

2.868 ± 1.952

Income level (yuan)

 < 3000/<$422

74

2.850 (1.932–4.328)

2.827 ± 1.952

 3000–5000/$422–$736

233

2.853 (1.938–4.440)

2.978 ± 1.847

 > 5000/>$736

24

3.116 (2.129–7.319)

3.310 ± 2.271

Job tenure (years)

 < 10

93

3.105 (2.213–4.794)

3.012 ± 1.770

 10–20

94

2.736 (2.004–4.578)

2.946 ± 1.913

 ≥ 20

144

2.965 (1.918–4.282)

2.956 ± 1.911

Type of work

 Oil

176

3.043 (2.116–5.135)

3.276 ± 1.881^a

 Oil recovery

34

2.616 (1.625–3.639)

2.503 ± 1.725^b

 Refining

49

2.816 (1.795–4.506)

2.721 ± 2.029^b

 Other

72

2.821 (1.768–4.078)

2.683 ± 1.883^b

Smoking

 Often

63

3.471 (2.158–4.936)

3.156 ± 1.914^c

 Occasional

40

3.438 (2.148–5.228)

3.279 ± 1.936^c

 Quit smoking

17

3.786 (2.390–8.302)

4.276 ± 2.177^c

 Nonsmoking

211

2.692 (1.910–3.970)

2.777 ± 1.847^d

Drinking

 Often

22

4.025 (2.252–7.745)

3.832 ± 2.250

 Occasional

130

3.152 (1.948–4.822)

3.095 ± 1.912

 Quit drinking

16

2.688 (2.141–6.508)

3.178 ± 2.147

 Nondrinking

163

2.722 (1.917–4.000)

2.755 ± 1.805

Physical exercise

 No exercise

66

2.704 (1.812–3.779)

2.713 ± 1.779

 <3 Times/week

109

2.720 (1.918–4.412)

2.950 ± 1.888

 ≥ 3 Times/week

46

3.492 (2.369–6.645)

3.681 ± 2.069

 Irregular

110

2.947 (1.905–4.073)

2.883 ± 1.891