Table 3 Relationship between work‐related manual handling activities and new‐onset knee pain among newly appointed workers.
| New‐onset knee pain at 1 year | New‐onset knee pain at 2 years | Relative risk* (95% CI) | |||
|---|---|---|---|---|---|
| Yes | No | Yes | No | ||
| Lift or carry weights in one hand (if yes, weight split at median†) | |||||
| None | 19 (5.7%) | 314 (94.3%) | 16 (6.8%) | 220 (93.2%) | 1.0 |
| <20 lbs | 22 (11.5%) | 169 (88.5%) | 21 (12.3%) | 150 (87.7%) | 2.1 (1.3 to 3.2) |
| >20 lbs | 14 (10.1%) | 125 (89.9%) | 14 (13.9%) | 87 (86.1%) | 1.7 (1.03 to 2.8) |
| Lift or carry weights in two hands (if yes, weight split at median†) | |||||
| None | 22 (7.2%) | 284 (92.8%) | 16 (6.5%) | 230 (93.5%) | 1.0 |
| <27 lbs | 14 (7.1%) | 184 (92.9%) | 14 (12.0%) | 103 (88.0%) | 1.2 (0.7 to 2.1) |
| >27 lbs | 18 (11.8%) | 134 (88.2%) | 21 (14.4%) | 125 (85.6%) | 1.6 (0.9 to 2.7) |
| Carry weights on shoulder (if yes, weight split at median†) | |||||
| None | 39 (7.2%) | 500 (72.8%) | 34 (8.3%) | 378 (91.7%) | 1.0 |
| <40 lbs | 8 (10.0%) | 72 (90.0%) | 11 (15.3%) | 61 (84.7%) | 1.4 (0.9 to 2.4) |
| >40 lbs | 8 (18.6%) | 25 (81.4%) | 7 (26.9%) | 19 (73.1%) | 1.6 (0.8 to 3.2) |
| Lift weights at or above shoulder level (if yes, weight split at median†) | |||||
| None | 36 (7.1%) | 472 (92.9%) | 34 (8.8%) | 353 (91.2%) | 1.0 |
| <28 lbs | 10 (12.0%) | 73 (88.0%) | 15 (17.4%) | 71 (82.6%) | 1.8 (1.1 to 2.9) |
| >28 lbs | 8 (11.9%) | 59 (88.1%) | 3 (8.3%) | 33 (91.7%) | 0.9 (0.5 to 1.7) |
| Pushing heavy weights (if yes, weight split at median†) | |||||
| None | 37 (8.4%) | 402 (91.6%) | 35 (10.1%) | 312 (89.9%) | 1.0 |
| <86 lbs | 10 (8.8%) | 104 (91.2%) | 9 (7.8%) | 106 (92.2%) | 1.1 (0.7 to 1.8) |
| >86 lbs | 6 (5.7%) | 99 (94.3%) | 8 (16.7%) | 40 (83.3%) | 1.0 (0.5 to 2.0) |
| Pull heavy weights (if yes, weight split at median†) | |||||
| None | 37 (7.4%) | 461 (92.6%) | 37 (9.3%) | 360 (90.7%) | 1.0 |
| <66 lbs | 9 (10.1%) | 80 (89.9%) | 6 (9.0%) | 61 (91.0%) | 1.2 (0.7 to 2.2) |
| >66 lbs | 7 (9.7%) | 65 (90.3%) | 6 (18.7%) | 26 (81.3%) | 1.6 (0.9 to 2.9) |
Median value of weights differed at t0 and t1. Weights split at median at t0 and at this value at t1.
*Adjusted for age, sex, occupational group, body mass index and physical activity.
†Exposures recorded for “last working day”.