Introduction
Study Population and Methods
Population
Baseline workers | Workers in analysis | Workers not in analysis | |
---|---|---|---|
N | 1,745 | 1,086 | 659 |
Gender | m = 1,222 (71 %)/f = 510 | m = 759 (70 %)/f = 327 | m = 463 (72 %)/f = 183 |
Age (years) | 35.9 ± 8.4 | 35.6 ± 8.7 | 35.4 ± 8.9 |
Hours per week | 38.3 ± 4.5 | 38.2 ± 4.7 | 38.2 ± 4.7 |
Years in current job | 9.9 ± 7.7 | 9.6 ± 7.6 | 9.5 ± 8.0 |
Data Collection
Assessment of Low Back Load
Variable | Observation | CLBL calculation | |
---|---|---|---|
Description | Category | Values | |
Trunk flexion (sagittal plane) | Neutral | <30° | 0° |
Mild flexion | 30°–60° | 45° | |
Extreme flexion | 60°–90° | 75° | |
Very extreme flexion | >90° | 90° | |
Trunk rotation (transverse plane) | Neutral | <30° | 0° |
Twisting | >30° | 30° | |
Arm elevation (sagittal plane) | Neutral | <30° | 15° |
Mild elevation | 30°–60° | 45° | |
Extreme elevation | 60°–90° | 75° | |
Very extreme elevation | >90° | 90° |
Statistical Analyses
Results
Population
LBP Risk Model
Risk factor | LBP | No LBP | B | OR (95 % CI), n = 1,086†
|
---|---|---|---|---|
Regression model
| ||||
CLBL | ||||
1st quintile | 109 | 107 | Reference | |
2nd quintile | 106 | 122 | −0.15 | 0.86 (0.59–1.25) |
3th quintile | 93 | 129 | −0.34 | 0.71 (0.49–1.04) |
4th quintile | 93 | 107 | −0.15 | 0.86 (0.59–1.26) |
5th quintile | 136 | 84 | 0.47 | 1.60 (1.10–2.35)* |
CLBL | ||||
1st quintile | Reference#
| |||
2nd quintile | 0.05 | 1.05 (0.70–1.58) | ||
3th quintile | −0.13 | 0.87 (0.57–1.33) | ||
4th quintile | 0.03 | 1.03 (0.68–1.57) | ||
5th quintile | 0.72 | 2.06 (1.32–3.20)* |
n | Minimum | Maximum | Mean | SD | |
---|---|---|---|---|---|
Category values
| |||||
1th quintiles | 216 | 0.09 | 0.49 | 0.29 | 0.11 |
2nd quintiles | 228 | 0.52 | 0.71 | 0.62 | 0.05 |
3th quintiles | 222 | 0.74 | 1.13 | 1.03 | 0.13 |
4th quintiles | 200 | 1.14 | 1.96 | 1.52 | 0.29 |
5th quintiles | 220 | 1.99 | 10.83 | 3.65 | 2.38 |
Total | 1,086 | 0.09 | 10.83 | 1.43 | 1.16 |
Risk factor | LBP | No LBP | OR (95 % CI), n = 1,086†
| OR (95 % CI), n = 1,086†
|
---|---|---|---|---|
Time in trunk flexion
| ||||
≤5 % time ≥30° | 256 | 287 | Referencea
| Referenceb
|
5–10 % time ≥30° | 96 | 110 | 1.01 (0.73–1.47) | 1.15 (0.74–1.78) |
>10 % time ≥30° & ≤5 % time ≥60° | 120 | 120 | 1.15 (0.83–1.58) | 0.91 (0.57–1.46) |
>5 % time ≥60° | 65 | 32 | 2.35 (1.46–3.79)* | 1.45 (0.77–2.73) |
Number of lifts
| ||||
Never | 151 | 161 | Referencea
| Referenceb
|
Never ≥10 kg/working day | 81 | 94 | 0.74 (0.50–1.09) | 0.69 (0.45–1.06) |
Never ≥25 kg/working day | 146 | 156 | 0.96 (0.68–1.36) | 0.77 (0.51–1.17) |
1–15 times ≥25 kg/working day | 96 | 107 | 0.86 (0.59–1.27) | 0.73 (0.44–1.19) |
>15 times ≥25 kg/working day | 63 | 31 | 2.22 (1.33–3.72)* | 1.60 (0.88–2.92) |
Number of lifts ≥25 kg
| ||||
Never | 378 | 411 | Referencea
| Referenceb
|
1–15 time/working day | 96 | 107 | 0.93 (0.67–1.29) | 0.92 (0.63–1.34) |
>15 times/working day | 63 | 31 | 2.38 (1.48–3.82)* | 2.03 (1.23–3.36)* |
CLBL
| ||||
1st quintile | Reference1
| |||
2nd quintile | 1.06 (0.70–1.59) | |||
3th quintile | 0.83 (0.51–1.33) | |||
4th quintile | 1.03 (0.60–1.78) | |||
5th quintile | 1.89 (1.04–3.45)* | |||
CLBL
| ||||
1st quintile | Reference2
| |||
2nd quintile | 0.97 (0.62–1.51) | |||
3th quintile | 0.88 (0.55–1.41) | |||
4th quintile | 1.05 (0.62–1.76) | |||
5th quintile | 1.96 (1.15–3.36)* | |||
CLBL
| ||||
1st quintile | Reference3
| |||
2nd quintile | 1.06 (0.71–1.60) | |||
3th quintile | 0.85 (0.56–1.31) | |||
4th quintile | 0.99 (0.62–1.57) | |||
5th quintile | 1.85 (1.17–2.92)* |