Table 3.
Associations of occupational tasks with radiographic and symptomatic knee OA: results of logistic regression models.
| Radiographic Knee OA | Symptomatic Knee OA | |||||
|---|---|---|---|---|---|---|
| No OA Exposed, N (%) | OA Exposed, N (%) | Adjusted OR* (95% CI) | No OA Exposed, N (%) | OA Exposed, N (%) | Adjusted OR* (95% CI) | |
| 10 tasks performed at longest job and no. of exposures† | ||||||
| Walk | 1245 (74.1) | 616 (71.1) | 1.01 (0.80–1.27) | 1420 (72.7) | 417 (75.4) | 1.46 (1.12–1.90) |
| Lift > 10 lbs | 767 (45.7) | 390 (45.0) | 1.06 (0.86–1.31) | 867 (44.5) | 277 (50.2)** | 1.42 (1.13–1.80) |
| Sit | 729 (43.4) | 318 (36.7)** | 0.86 (0.70–1.05) | 843 (43.2) | 183 (33.6)** | 0.72 (0.57–0.90) |
| Stand | 1108 (66.0) | 575 (66.3) | 1.00 (0.81–1.23) | 1269 (65.0) | 400 (72.3)** | 1.38 (1.08–1.77) |
| Bend, twist, reach | 1042 (62.0) | 529 (60.9) | 0.91 (0.74–1.12) | 1182 (60.5) | 364 (65.7)** | 1.26 (0.99–1.60) |
| Squat | 372 (22.2) | 189 (21.8) | 1.13 (0.88–1.45) | 425 (21.8) | 129 (23.3) | 1.27 (0.97–1.68) |
| Climb stairs | 397 (23.7) | 163 (18.8)** | 0.80 (0.63–1.03) | 445 (22.8) | 107 (19.4) | 0.96 (0.73–1.26) |
| Crawl | 111 (6.6) | 65 (7.5) | 1.15 (0.78–1.71) | 126 (6.5) | 49 (8.8)** | 1.59 (1.05–2.41) |
| Crouch or kneel | 222 (14.2) | 90 (11.5) | 0.81 (0.59–1.11) | 249 (13.7) | 63 (12.0) | 0.95 (0.67–1.36) |
| Heavy work, standing | 190 (12.1) | 104 (13.3) | 1.11 (0.81–1.51) | 211 (11.6) | 82 (15.7)** | 1.44 (1.03–2.02) |
| No. of exposures†† | mean = 3.3 | mean = 3.2 | 1.00 (0.95–1.05) | mean = 3.2 | mean = 3.4 | 1.09 (1.03–1.15) |
| Lifetime exposure to 8 occupational tasks and no. of exposures | ||||||
| Light work while standing > 50% of job | 458 (27.1) | 226 (25.8) | 0.97 (0.78–1.21) | 521 (26.4) | 159 (27.1) | 1.06 (0.83–1.35) |
| Heavy work while standing > 50% of job | 320 (18.9) | 188 (21.5) | 1.13 (0.88–1.44) | 363 (18.3) | 142 (24.2)** | 1.32 (1.02–1.72) |
| Sitting > 50% of job | 845 (49.9) | 375 (43.0)** | 0.86 (0.71–1.05) | 983 (49.8) | 233 (39.9)** | 0.73 (0.59–0.92) |
| Kneeling > 50% of job | 203 (12.0) | 109 (12.5) | 0.98 (0.73–1.33) | 236 (12.0) | 74 (12.7) | 1.03 (0.74–1.44) |
| Walking > 50% of job | 742 (43.9) | 282 (43.9) | 1.00 (0.82–1.23) | 845 (42.9) | 279 (47.8)** | 1.24 (0.99–1.55) |
| Lifting 10 kg ≥ 10 ×/week | 692 (40.8) | 369 (42.2) | 1.18 (0.95–1.46) | 810 (41.0) | 249 (42.5) | 1.13 (0.89–1.44) |
| Lifting 20 kg ≥ 10 ×/week | 412 (24.3) | 208 (23.8) | 0.94 (0.73–1.22) | 473 (23.9) | 145 (24.7) | 1.05 (0.79–1.39) |
| Lifting 50 kg ≥ 10 ×/week | 147 (8.7) | 90 (10.3) | 0.82 (0.58–1.15) | 170 (8.6) | 66 (11.2) | 0.98 (0.67–1.43) |
| No. of exposures†† | mean = 2.2 | mean = 2.5 | 0.99 (0.93–1.06) | mean = 2.2 | mean = 2.3 | 1.03 (0.96–1.10) |
*
Multivariable logistic regression models adjusted for age, gender, race, body mass index, smoking (ever and current vs never), prior knee injury, and household tasks.
**
Significant chi-square test (p < 0.05).
†
Tasks for longest job are 0 = never, seldom, sometimes; 1 = often or always.
††
Excludes sitting.