Unadjusted and adjusted hazard ratios evaluating the effects of interventions on incident musculoskeletal disorders by body region (n = 182)
| Trackball intervention | Armboard intervention | |||||
|---|---|---|---|---|---|---|
| Hazard ratio* | 95% CI | p Value | Hazard ratio* | 95% CI | p Value | |
| *Cox proportional hazard ratio: those without the intervention are the reference group. | ||||||
| †Variables: trackball, armboard, pre-intervention mean neck/shoulder pain value, age, gender, composite psychological strain, iso-strain, ethnicity, pain medication, current smoker, hand intensive activity outside of work. | ||||||
| ‡Variables: trackball, armboard, pre-intervention mean right upper extremity pain value, age, composite psychological strain, iso-strain, seniority, total break minutes/day, educational level, ethnicity, current smoker, hand intensive activity outside of work. | ||||||
| §Variables: trackball, armboard, pre-intervention mean left upper extremity pain value, age, gender, composite psychological strain, iso-strain, job title, typing speed, body mass index, educational level, ethnicity, low back pain score, previous surgery in neck, shoulders, or upper extremities, pain medication, current smoker, weekly exercise, hand intensive activity outside of work. | ||||||
| Neck/shoulder disorders | ||||||
| Unadjusted model | 0.61 | 0.31–1.17 | 0.14 | 0.53 | 0.28–1.03 | 0.06 |
| Adjusted model† | 0.62 | 0.30–1.28 | 0.19 | 0.49 | 0.24–0.97 | 0.04 |
| Right upper extremity disorders | ||||||
| Unadjusted model | 1.30 | 0.62–2.71 | 0.49 | 0.81 | 0.39–1.69 | 0.57 |
| Adjusted model‡ | 1.26 | 0.56–2.86 | 0.58 | 0.64 | 0.28–1.45 | 0.29 |
| Left upper extremity disorders | ||||||
| Unadjusted model | 0.56 | 0.21–1.52 | 0.26 | 0.66 | 0.25–1.73 | 0.40 |
| Adjusted model§ | 0.19 | 0.04–0.90 | 0.04 | 0.29 | 0.08–1.05 | 0.06 |