Table 1 Characteristics of study populationâ€
|  | Age 50–60 years (n = 256) | Age 60–70 years (n = 181) | Age 70–80 years (n = 44) | p value‡ |
|---|---|---|---|---|
Age (year) | 55.9 (2.3) | 64.7 (3.0) | 73.3 (2.3) | < 0.001 |
Females, % | 52 | 48 | 45 | 0.604 |
BMI (kg/m2) | 27.9 (4.8) | 27.4 (3.9) | 27.6 (3.9) | 0.580 |
Radiographic OA, % | 56 | 59 | 72 | 0.170 |
 Joint space narrowing | 56 | 58 | 72 | 0.173 |
 Osteophytes | 6 | 11 | 5 | 0.128 |
Tibial bone size (mm2) | 3279.9 (469.5) | 3366.6 (498.0) | 3382.1 (558.5) | 0.190 |
WOMAC pain score (0–45), median (IQR) | 0.5 (0 to 4) | 0 (0 to 3) | 1 (0 to 4) | 0.541 |
 Any pain, % | 50 | 46 | 52 | 0.612 |
WOMAC function score (0–153), median (IQR) | 0 (0 to 8.5) | 1 (0 to 7) | 4.5 (0 to 16) | 0.095 |
 Any functional disability, % | 49 | 53 | 68 | 0.057 |
History of knee surgery, % | 11 | 9 | 7 | 0.741 |
History of knee injury, %* | 14 | 10 | 9 | 0.413 |
Physical activity (steps/day) | 9639.8 (3239.9) | 9172.3 (3128.9) | 7625.0 (2803.0) | < 0.001 |
Cartilage volume (mm3) | ||||
 Medial tibial | 1509.5 (398.1) | 1523.8 (449.3) | 1438.6 (397.0) | 0.479 |
 Lateral tibial | 2096.4 (591.5) | 2046.9 (651.5) | 1803.2 (599.9) | 0.015 |
 Total tibial | 3606.0 (917.1) | 3570.7 (1018.6) | 3241.8 (907.5) | 0.065 |