Distribution of demographic characteristics of participants with OAI by incidence of shoulder pain at Year 4. Baseline data unless otherwise indicated. Values are mean (SD) unless otherwise specified.
| Characteristics | Neither Shoulder, n = 1291 | One Shoulder, n = 176 | Both Shoulders, n = 88 | p |
|---|---|---|---|---|
| No. persistently painful knees, yrs 0–3 | < 0.001 | |||
| None | 894 (69.2) | 104 (59.1) | 43 (48.9) | |
| 1 knee* | 242 (18.7) | 42 (23.9) | 24 (27.3) | |
| Both knees | 155 (12.0) | 30 (17.0) | 21 (23.9) | |
| Female, % | 44.7 | 41.5 | 33.0 | 0.08 |
| Age, yrs | 61.4 (9.1) | 61.6 (9.3) | 61.6 (8.6) | 0.91 |
| BMI, kg/m2 | 28.1 (4.7) | 28.6 (5.0) | 29.0 (4.9) | 0.15 |
| Difficulty standing from sitting** | 0.5 (0.77) | 0.7 (0.8) | 1.0 (1.0) | < 0.001 |
| CES-D score | 5.3 (5.73) | 7.0 (7.26) | 6.8 (7.08) | < 0.001 |
| Prevalence of hip, ankle, or foot pain, % | 29.6 | 37.5 | 44.3 | 0.006 |
| Leg used to kick ball | 0.35 | |||
| Right leg | 91.3 | 91.9 | 92.2 | |
| Left leg | 7.3 | 6.6 | 5.9 | |
| Both legs | 1.3 | 1.4 | 2.0 | |
| Change in BMI | 0.20 (1.88) | 0.10 (1.78) | 0.13 (2.23) | 0.99 |
| Change in depression score | 0.6 (5.62) | 0.4 (7.94) | 3.1 (7.14) | < 0.001 |
↵* Averaged over both knees, or for the sore knee if only 1 knee is painful.
↵** Difficulty standing from sitting is subscale 3 of the WOMAC function scale. Statistical significance is p ≤ 0.05 and in bold face. OAI: Osteoarthritis Initiative; BMI: body mass index; CES-D: Center for Epidemiologic Studies Depression Scale; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index.