Table 1 Baseline characteristics of the study population with incident and progression of knee and hip radiographic osteoarthritis.
| Incident population (K&L ⩽grade 1 at baseline) | Progression population (K&L ⩾grade 1 and ⩽grade 3 at baseline) | |||
|---|---|---|---|---|
| Knee | Hip | Knee | Hip | |
| Number of participants (number of joints) | 1372 (2570) | 2852 (5481) | 532 (865) | 1676 (2535) |
| Mean (SD) age (years) | 66.3 (6.7) | 65.7 (6.7) | 68.6 (7.0) | 66.1 (6.9) |
| Sex (% women) | 57.7 | 57.9 | 68.4 | 52.1 |
| Mean (SD) BMI, (kg/m2) | 26.0 (3.5) | 26.3 (3.6) | 27.4 (3.9) | 26.3 (3.5) |
| Incident ROA (%) | 5.5 | 3.9 | — | — |
| Progression of ROA | ||||
| JSN ⩾1 mm (%) | — | — | 21.8 | 8.7 |
| JSN ⩾1.5 mm (%) | — | — | 8.1 | 2.5 |
| Increase in K&L (%) | — | — | 11.4 | 10.1 |
BMI, body mass index; JSN, joint space narrowing; K&L, Kellgren and Lawrence; ROA, radiographic osteoarthritis.
Incident ROA is defined by baseline K&L ⩽grade 1 and follow‐up K&L ⩾grade 2.
Progression of ROA is defined by two definitions—namely a JSN of ⩾1, and 1.5 mm at follow‐up, and by an increase of minimally 1 grade in K&L index.