Adjusted odds risk ratios* for stress symptoms according to work characteristics at baseline
| Baseline | Follow up | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | Stress symptoms | N† | Stress symptoms | |||||||
| n | % | OR | 95% CI | n† | % | OR | 95% CI | |||
| *Adjustment for individual factors: data collecting centre, age, gender, body mass index, physical leisure time activity, pain pressure threshold, intrinsic effort, living as married, psychiatric disorder. | ||||||||||
| †N is the total number of follow up observations and n is the number of new stress symptom cases identified during follow up (for example: among the 813 workers without repetitive work at baseline, 1585 follow up observations were undertaken among those without stress symptoms at baseline revealing 24 new cases with stress symptoms). | ||||||||||
| MVC, maximal voluntary contraction. | ||||||||||
| Repetitive work | ||||||||||
| No | 813 | 42 | 5.2 | 1.0 | – | 1585 | 24 | 1.5 | 1.0 | – |
| Yes | 2033 | 98 | 4.8 | 0.9 | 0.6 to 1.4 | 3576 | 76 | 2.1 | 1.3 | 0.6 to 2.2 |
| Task cycle time (seconds) | ||||||||||
| Continuous variable, repetitive work only, 10 unit increment | 2033 | 98 | 4.8 | 1.0 | 0.99 to 1.00 | 3576 | 76 | 2.1 | 1.0 | 0.99 to 1.00 |
| Grouped exposure, all reference | 813 | 42 | 5.2 | 1.0 | – | 1585 | 24 | 1.5 | 1.0 | – |
| >21 seconds | 1042 | 55 | 5.3 | 1.0 | 0.6 to 1.6 | 1701 | 34 | 2.0 | 1.4 | 0.6 to 2.5 |
| 1–20 seconds | 991 | 43 | 4.3 | 0.8 | 0.5 to 1.3 | 1875 | 42 | 2.2 | 1.2 | 0.6 to 2.4 |
| Duration of exertion (% of cycle time) | ||||||||||
| Continuous variable, repetitive work only, 10 unit increment | 2033 | 98 | 4.8 | 0.9 | 0.8 to 1.2 | 3576 | 76 | 2.1 | 0.9 | 0.8 to 1.1 |
| Grouped exposure, all reference | 813 | 42 | 5.2 | 1.0 | – | 1585 | 24 | 1.5 | 1.0 | – |
| 0–75% | 969 | 47 | 4.9 | 1.0 | 0.6 to 1.5 | 1859 | 40 | 2.2 | 0.8 | 0.5 to 1.3 |
| >75% | 1064 | 51 | 4.8 | 0.9 | 0.7 to 1.1 | 1717 | 36 | 2.1 | 1.0 | 0.8 to 1.3 |
| Repetitive work (wrist movements/minute) | ||||||||||
| Continuous variable, repetitive work only, 10 unit increment | 2033 | 98 | 4.8 | 0.9 | 0.5 to 1.7 | 3576 | 76 | 2.1 | 1.0 | 0.6 to 1.6 |
| Grouped exposure, all reference | 813 | 42 | 5.2 | 1.0 | – | 1585 | 24 | 1.5 | 1.0 | – |
| 1–15/minute | 1288 | 61 | 4.7 | 1.0 | 0.6 to 1.5 | 2391 | 53 | 2.2 | 1.3 | 0.5 to 1.9 |
| 16–60/minute | 745 | 37 | 5.0 | 0.9 | 0.5 to 1.5 | 1185 | 23 | 1.9 | 1.2 | 0.8 to 3.7 |
| Force requirements | ||||||||||
| Reference | 813 | 42 | 5.2 | 1.0 | – | 1585 | 24 | 1.5 | 1.0 | – |
| low <10 % of MVC | 1092 | 58 | 5.3 | 1.0 | 0.6 to 1.6 | 1979 | 48 | 2.4 | 1.5 | 0.9 to 2.5 |
| High ⩾10 % of MVC | 941 | 40 | 4.3 | 0.9 | 0.7 to 1.2 | 1597 | 28 | 1.8 | 1.0 | 0.8 to 1.4 |