Table 2.
Job exposures by CTS case status
| Mean or number (%) | CTS non-cases n=318 | CTS cases n=29 | p Value (χ2 or t test) | ||
|---|---|---|---|---|---|
| All n=347 | Range (SD) | ||||
| Observer RPE avg | 2.8 | 1–6 (1.2) | 2.8 (1.2) | 3.1 (1.2) | 0.11 |
| Observer RPE peak | 4.1 | 1–10 (1.9) | 4.0 (1.9) | 4.5 (1.7) | 0.20 |
| Worker RPE avg | 2.6 | 0.7–7.8 (1.4) | 2.6 (1.4) | 3.2 (1.6) | 0.01 |
| Worker RPE peak | 4.3 | 1–10 (2.5) | 4.2 (2.5) | 5.4 (2.4) | 0.01 |
| Force Match avg | 3.9 | 0.5–11.4 (2.5) | 3.8 (2.4) | 4.9 (2.7) | 0.02 |
| Force Match peak | 6.0 | 1–13.1 (3.5) | 5.9 (3.5) | 7.5 (3.5) | 0.02 |
| Exertions/min* | 14.4 | 0.7–50.9 (9.2) | 14.1 (9.1) | 16.9 (10.4) | 0.11 |
| Forceful exertions/min* | 4.1 | 0–34.1 (5.4) | 4.0 (5.3) | 6.0 (5.6) | 0.05 |
| %Time in exertion* | 70.1 | 93.7–100 (18.7) | 69.9 (18.5) | 71.9 (20.6) | 0.59 |
| %Time in forceful exertion* | 17.5 | 0–96.9 (18.7) | 16.4 (17.8) | 29.5 (24.4) | <0.01 |
| 0 to <20% | 216 (63.3) | 210 (66.0) | 10 (34.3) | <0.001 | |
| 20% to <60% | 112 (32.8) | 100 (31.4) | 14 (48.3) | ||
| 60%+ | 13 (3.8) | 8 (2.6) | 5 (17.2) | ||
| ACGIH TLV | 0.32 | ||||
| <AL | 102 (29.4) | 97 (30.5) | 5 (17.2) | ||
| AL to TLV | 10 (2.9) | 9 (2.8) | 1 (3.4) | ||
| TLV+ | 235 (67.7) | 212 (66.7) | 23 (79.3) | ||
| ACGIH TLV ratio (TLR) | 1.53 | 0.13–7.52 (1.13) | 1.50 (1.11) | 2.09 (1.35) | <0.01 |
| Observer HAL avg | 4.2 | 0.1–8 (1.5) | 4.1 (1.5) | 4.6 (1.6) | 0.09 |
| Tabulated HAL avg | 3.6 | 0.2–7 (1.7) | 3.6 (1.7) | 4.0 (1.6) | 0.19 |
| Observer HAL peak | 5.1 | 1–10 (1.7) | 5.1 (1.7) | 5.3 (1.7) | 0.54 |
| Tabulated HAL peak | 4.2 | 1–7 (1.8) | 4.2 (1.8) | 4.6 (1.8) | 0.21 |
| Vibration % yes | 35.7 | 0–100 (48.0) | 34.6 (47.6) | 48.3 (50.9) | 0.14 |
| Wrist posture avg, % ROM† | 18.8 | 2.4–50.3 (6.9) | 18.8 (7.0) | 19.4 (6.2) | 0.67 |
| Wrist posture peak % ROM† | 75.3 | 10.0–100 (20.8) | 75.5 (20.9) | 73.4 (18.8) | 0.61 |
| Wrist flex/extend avg % ROM† | 19.7 | 2.1–55.1 (7.3) | 19.6 (7.2) | 20.7 (8.7) | 0.46 |
| Wrist flex/extend peak % ROM† | 59.6 | 5.3–100 (20.7) | 59.5 (20.8) | 60.7 (19.9) | 0.76 |
| Wrist deviation avg % ROM† | 17.7 | 0–57.8 (9.7) | 17.8 (9.6) | 17.5 (10.2) | 0.87 |
| Wrist deviation peak % ROM† | 70.1 | 1–100 (22.7) | 70.4 (22.8) | 66.1 (22.0) | 0.33 |
| job strain | <0.01 | ||||
| Low/passive/active | 234 (67.4) | 221 (69.5) | 13 (44.8) | ||
| High | 98 (28.2) | 86 (27.0) | 12 (41.4) | ||
| Missing | 15 (4.3) | 11 (3.5) | 4 (13.8) | ||
6 had missing values for these variables.
8 had missing values for these variables. Exposure variables represent the average or peak of measurements across data collection visits. Wrist posture includes both flexion/extension and radial/ulnar deviation, calculated as % of full range of motion of all sampled video frames for a task, weighted by % time in task for multitask jobs. ACGIH TLV, AL is based on ACGIH TLV for HAL and TLR on Drinkaus 2005; HAL, hand activity level. Job strain, psychological demand vs decision latitude as defined by Karasek 1998.
ACGIH, American Conference for Governmental Industrial Hygienists; AL, action limit; CTS, carpal tunnel syndrome; HAL, hand activity level; ROM, Range of motion; RPE, ratings of perceived exertion; TLV, Threshold Limit Value.