Table 2 Univariate regression analyses: variables associated with back pain within 6 and 12 months of baseline

Individual factors

  Body weight (Kg)

  < 87

.

.

.

.

.

.

82

37

(45)

1.00

Reference

.

  ≥ 87

.

.

.

.

.

.

36

22

(61)

1.91

0.86–4.25

0.112

  Body height (m)

  < 1.86

90

23

(26)

1.00

Reference

.

74

30

(41)

1.00

Reference

.

  ≥ 1.86

47

21

(45)

2.35

1.12–4.96

0.024

44

29

(66)

2.84

1.30–6.17

0.009

Health-related factors

 No

75.6

17

(22)

1.00

Reference

.

90

36

(40)

1.00

Reference

.

 Yes

61.4

27

(44)

3.60

1.59–8.14

0.002

28

23

(82)

6.90

2.40–19.82

<0.001

 No

104

26

(25)

1.00

Reference

.

66.6

27

(41)

1.00

Reference

.

 Yes

33

18

(55)

2.71

1.29–5.68

0.008

51.4

32

(62)

2.43

1.45–5.14

0.021

 No

.

.

.

.

.

.

83

38

(46)

1.00

Reference

.

 Yes

.

.

.

.

.

.

35

21

(60)

1.78

0.80–3.96

0.160

Work-related factors

 Infantry (Assault)

93

26

(28)

1.00

Reference

.

81

36

(44)

1.00

Reference

.

 Ranger

24

7

(29)

1.06

0.39–2.86

0.907

20

11

(55)

1.52

0.57–4.09

0.399

 CBC-Crew^c

20

11

(55)

3.15

1.17–8.48

0.023

17

12

(71)

3.00

0.97–9.30

0.057

  < 1/2 work day

111

31

(28)

1.00

Reference

.

93

42

(45)

1.00

Reference

.

  ≥ 1/2 work day

26

13

(50)

2.58

1.08–6.18

0.033

25

17

(68)

2.58

1.01–6.57

0.047

  < 1/4 work day

112

33

(29)

1.00

Reference

.

93

43

(46)

1.00

Reference

.

  ≥ 1/4 work day

25

11

(44)

1.88

0.77–4.57

0.163

25

16

(64)

2.07

0.83–5.15

0.119

  Vibrating floor/seat

  < 1/4 work day

.

.

.

.

.

.

86.8

39.8

(46)

1.00

Reference

.

  ≥ 1/4 work day

.

.

.

.

.

.

31.2

19.2

(62)

1.89

0.82–4.38

0.135

 Pass

.

.

.

.

.

.

76.2

42.2

(55)

1.00

Reference

.

 Fail

.

.

.

.

.

.

41.8

16.8

(40)

0.54

0.24–1.20

0.129

 Pass

76.6

30.1

(39)

1.00

Reference

.

.

.

.

.

.

.

 Fail

60.4

13.9

(23)

0.46

0.21–1.01

0.054

.

.

.

.

.

.