Table 1 Odds ratio for participants’ individual characteristics and occupational risk factors

Previous History (yes/no)

14/59

14/80

0.73

0.32–1,66

0.46

Physical Activity

31/42

43/51

1.14

0.61–2.11

0.67

 < 3 months

0/73

11/83

Not calculated

Not calculated

 3–6 months

0/73

1/93

Not calculated

Not calculated

 7–12 months

0/73

2/92

Not calculated

Not calculated

 13–60 months

5/68

35/59

8.06

2.96–21.92

0.00**

 61–120 months

9/64

19/75

1.80

0.76–4.25

0.17

 > 121 months

60/13

26/68

0.08

0.03–0.17

0.00**

 < 3 months

1/72

11/83

9.54

1.20–75.71

0.01*

 3–6 months

5/68

3/91

0.44

0.10–1.94

0.27

 7–12 months

3/70

3/91

0.76

0.15–3.92

0.75

 13–60 months

16/57

30/64

1.67

0.82–3.37

0.15

 61–120 months

16/57

17/77

0.78

0.36–1.68

0.53

 > 121 months

32/41

31/63

0.63

0.33–1.18

0.15