Table 2 Association between socio-demographic factors, physical function, baseline knee conditions, and incident ROA
Characteristic | Incident OA (n = 102) | Non-incident OA (n = 496) | Crude OR (95% CI) | P value | Adjusted OR (model 1) (95% CI) | P value | Adjusted OR (model 2) (95% CI) | P value |
|---|---|---|---|---|---|---|---|---|
Baseline socio-demographic, BMI, and history of knee injury | ||||||||
 Agea | 61.15 ± 6.37 | 58.77 ± 6.54 | 1.053 (1.021-1.087) | <0.01 | 1.067 (1.032-1.102) | <0.01 | 1.079 (1.042-1.117) | <0.01 |
 Gendera |  |  |  |  |  |  |  |  |
  Male | 31 (30.4%) | 186 (37.5%) | 1.0 (reference) |  | 1.0 (reference) |  | 1.0 (reference) |  |
  Female | 71 (69.6%) | 310 (62.5%) | 1.373 (0.867-2.174) | 0.177 | 1.815 (1.111-2.964) | 0.017 | 1.756 (1.071-2.877) | 0.025 |
 BMIa |  |  |  |  |  |  |  |  |
  Normal | 35 (34.3%) | 224 (45.25%) | 1.0 (reference) |  | 1.0 (reference) |  |  |  |
  Overweight | 60 (58.8%) | 225 (45.4%) | 1.699 (1.076-2.682) | 0.023 | 2.072 (1.278-3.358) | 0.003 | 2.086 (1.286-3.385) | <0.01 |
  Obesity | 7 (6.9%) | 47 (9.5%) | 0.940 (0.394-2.246) | 1.118 | 0.459 (0.459-2.742) | 0.806 | 1.158 (0.474-2.831) | 0.747 |
 History of knee injurya |  |  |  |  |  |  |  |  |
  No | 97 (95.1%) | 471 (95%) | 1.0 (reference) |  | 1.0 (reference) |  | 1.0 (reference) |  |
  Yes | 5 (4.9%) | 25 (5%) | 0.961 (0.359-2.572) | 0.937 | 0.983 (0.364-2.652) | 0.973 | 1.038 (0.381-2.829) | 0.942 |
 Educationa |  |  |  |  |  |  |  |  |
  Primary school | 19 (18.6%) | 117 (23.6%) | 1.0 (reference) |  | 1.0 (reference) |  | 1.0 (reference) |  |
  Middle school or above | 83 (81.4%) | 379 (76.4%) | 1.351 (0.787-2.319) | 0.275 | 1.320 (0.764-2.283) | 0.32 | 1.329 (0.764-2.313) | 0.314 |
Baseline physical function of the knee | ||||||||
 Range of motionb | 128.27 ± 7.10 | 129.95 ± 6.46 | 0.955 (0.930-0.981) | <0.01 | 0.954 (0.928-0.981) | <0.01 | 0.952 (0.923-0.983) | <0.01 |
 Flexion contractureb | 1.46 ± 2.86 | 1.19 ± 2.15 | 1.071 (0.999-1.147) | 0.052 | 1.072 (0.998-1.151) | 0.058 | 1.068 (0.993-1.150) | 0.078 |
 50-foot walk testb | 13.14 ± 2.86 | 12.58 ± 2.57 | 1.081 (1.003-1.164) | 0.041 | 1.002 (0.941-1.11) | 0.601 | 1.032 (0.950-1.122) | 0.452 |
 Chair stand testa | 8.82 ± 2.13 | 8.37 ± 2.20 | 1.087 (0.994-1.188) | 0.066 | 1.056 (0.962-1.159) | 0.252 | 1.056 (0.960-1.161) | 0.265 |
Baseline knee joint condition in knee level | ||||||||
 Baseline K/L gradeb |  |  |  |  |  |  |  |  |
  0 | 90 (44.1%) | 831 (83.8%) | 1.0 (reference) |  | 1.0 (reference) |  | 1.0 (reference) |  |
  1 | 114 (55.9%) | 161 (16.2%) | 8.769 (5.905-13.022) | <0.01 | 8.552 (5.575-13.120) | <0.01 | 8.527 (5.489-13.246) | <0.01 |
 Baseline knee painb |  |  |  |  |  |  |  |  |
  No | 179 (87.7%) | 900 (90.7%) | 1.0 (reference) |  | 1.0 (reference) |  | 1.0 (reference) |  |
  Yes | 25 (12.3%) | 92 (9.3%) | 1.646 (0.970-2.793) | 0.065 | 1.560 (0.903-2.694) | 0.111 | 1.541 (0.848-2.800) | 0.156 |
 Contralateral knee painb |  |  |  |  |  |  |  |  |
  No | 179 (87.7%) | 900 (90.7%) | 1.0 (reference) |  | 1.0 (reference) |  | 1.0 (reference) |  |
  Yes | 25 (12.3%) | 92 (9.3%) | 0.960 (0.504-1.831) | 0.902 | 0.770 (0.383-1.546) | 0.462 | 0.735 (0.361-1.496) | 0.395 |