Table 1 Characteristics of the individuals in controls and steroid-induced ONFH patients
Variables | Cases (n = 199) | Controls (n = 506) | p |
|---|---|---|---|
N (%) | N (%) | ||
 Age, years |  |  |  |
 Mean ± SD | 41.21 ± 12.90 | 42.58 ± 13.15 | 0.212a |
  ≤ 45 | 129 (65%) | 275 (54%) |  |
  > 45 | 70 (35%) | 231 (46%) |  |
 Gender |  |  | < 0.001b |
  Male | 116 (58%) | 423 (84%) |  |
  Female | 83 (42%) | 83 (16%) |  |
 Hip lesions |  |  |  |
  Unilateral | 142 (71%) |  |  |
  Bilateral | 55 (28%) |  |  |
 Course, months |  |  |  |
  > 25 | 67 (34%) |  |  |
  ≤ 25 | 132 (66%) |  |  |