Table 2.
Prevalence of knee OA and knee symptoms by components of socioeconomic status.
| Income | Education | Occupation | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Q1 | Q2 | Q3 | Q4 | P value | Elementary | Middle school | High school | College or more | P value | Managerial | Non-managerial | None | P value | |
| Male | ||||||||||||||
| Knee OA | 30.3 (1.7) | 21.6 (1.6) | 18.9 (1.7) | 14.6 (1.5) | < .0001 | 28.2 (1.6) | 21.4 (1.8) | 18.2 (1.3) | 13.6 (1.7) | < .0001 | 11.5 (1.3) | 22.7 (1.2) | 27 (1.5) | < .0001 |
| Knee pain | 17.4 (1.3) | 12.5 (1.3) | 8.7 (1.2) | 6.8 (1) | < .0001 | 9.2 (1) | 6.3 (1) | 2.5 (0.6) | 2.6 (0.7) | < .0001 | 5.1 (0.9) | 13.1 (1) | 13.4 (1.1) | < .0001 |
| Knee stiffness | 17.5 (1.2) | 13.6 (1.5) | 6.5 (0.9) | 5.8 (1) | < .0001 | 8.7 (0.9) | 5.3 (0.9) | 3.1 (0.7) | 1.9 (0.6) | < .0001 | 1.8 (0.7) | 5.8 (0.7) | 6.8 (0.8) | < .0001 |
| RKOA | ||||||||||||||
| w/ knee pain | 28.7 (2.5) | 22.8 (3.1) | 13.7 (3) | 12.1 (3.4) | 0.0005 | 28.4 (2.7) | 23.3 (3.5) | 12.8 (2.8) | 8.3 (2.7) | 0.0123 | 5.9 (2.2) | 21.9 (2.2) | 24.9 (2.4) | < .0001 |
| w/ knee stiffness | 14 (2.1) | 11 (2.7) | 4.4 (1.7) | 6.7 (2.2) | < .0001 | 12.8 (1.9) | 12.7 (2.7) | 4.9 (1.9) | 5.6 (2.4) | 0.0125 | 2.2 (1.3) | 10.8 (1.7) | 11.3 (2) | 0.0143 |
| w/ spondylosis | 49.7 (3.3) | 35.1 (3.4) | 38.1 (4.8) | 24.1 (4) | < .0001 | 45.8 (3.3) | 34.1 (4.4) | 33.9 (3.6) | 33 (5.6) | 0.0298 | 19 (4.6) | 36.9 (2.8) | 48.2 (3.3) | < .0001 |
| Female | ||||||||||||||
| Knee OA | 60.1 (1.4) | 39 (1.6) | 35 (1.9) | 28.5 (1.8) | < .0001 | 53.7 (1.2) | 32.5 (1.9) | 23.7 (1.6) | 22.3 (3.2) | < .0001 | 27.5 (2) | 43.8 (1.7) | 47.6 (1.1) | < .0001 |
| Knee pain | 42.2 (1.4) | 26.6 (1.5) | 20.3 (1.6) | 18.3 (1.4) | < .0001 | 26.4 (1.4) | 13.9 (1.2) | 11 (1.2) | 9 (1) | < .0001 | 19.2 (1.7) | 29.3 (1.5) | 31.6 (1.1) | < .0001 |
| Knee stiffness | 37.7 (1.1) | 19.3 (1.7) | 14 (1.3) | 9.5 (1.7) | < .0001 | 22.5 (1) | 9.2 (1.2) | 6.9 (0.9) | 4.2 (1.2) | < .0001 | 9.4 (1.3) | 16.5 (1.3) | 18.6 (0.9) | < .0001 |
| RKOA | ||||||||||||||
| w/ knee pain | 52.7 (1.9) | 42.1 (2.6) | 33.2 (3.1) | 34.9 (3.2) | < .0001 | 51 (1.5) | 31.1 (3.2) | 21.9 (3.4) | 14.3 (4.6) | < .0001 | 35.7 (3.7) | 42.1 (2.4) | 47.2 (1.7) | 0.0092 |
| w/ knee stiffness | 33.3 (2) | 25.5 (2.5) | 19.9 (2.6) | 18.9 (2.7) | < .0001 | 31.4 (1.6) | 17.6 (2.7) | 13.9 (2.7) | 8.9 (4.2) | < .0001 | 22.1 (3.4) | 25.5 (2.3) | 28.9 (1.6) | 0.1411 |
| w/ spondylosis | 53.8 (1.9) | 43.1 (2.6) | 37.8 (3.1) | 38.5 (3.3) | < .0001 | 52.4 (1.7) | 34.5 (3.3) | 25.4 (3.1) | 21.5 (5.9) | < .0001 | 32.6 (4) | 47.2 (2.7) | 48.8 (1.7) | 0.0009 |
Numbers are n% (SE).
OA, osteoarthritis; RKOA, radiographic knee osteoarthritis.