Table 2. Regression models.
| Cortex | White matter | Ventricle | Whole brain | |
| Coefficient (95% CI) | Coefficient (95% CI) | Coefficient (95% CI) | Coefficient (95% CI) | |
| Model 1 (linear model) | ||||
| Age | −0.73 (−2.08, 0.62) | 0.67 (−0.57, 1.92) | 0.49 (0.33, 0.65) | 0.43 (−1.40, 2.26) |
| Sex (ref.a: female) | 97.31 (64.18, 130.45) | 41.51 (10.95, 72.06) | 7.26 (3.31, 11.21) | 146.08 (101.23, 190.93) |
| Model 2 (non-linear model) | ||||
| <40 (n = 24) (ref.) | – | – | – | – |
| 40∼49 (n = 19) | −18.44 (−65.74, 28.86) | 59.69 (18.94, 100.44) | 3.86 (−1.84, 9.56) | 45.12 (−18.11, 108.34) |
| 50∼59 (n = 34) | −22.76 (−63.61, 18.08) | 52.49 (17.31, 87.68) | 6.73 (1.80, 11.65) | 36.46 (−18.14, 91.05) |
| ≧60 (n = 8) | −3.95 (−66.61, 58.71) | 5.11 (−48.87, 59.09) | 21.66 (14.11, 29.22) | 22.82 (−60.93, 106.58) |
| Sex (ref.: female) | 96.67 (62.93, 130.41) | 44.47 (15.40, 73.54) | 7.79 (3.72, 11.86) | 148.92 (103.82, 194.03) |
| p-value (LRT b) | 0.61 | 0.005 | 0.02 | 0.43 |
| Model 3 (quadratic model) | ||||
| Age | 0.11 (−7.68, 7.91) | 9.85 (2.96, 16.74) | −0.74 (−1.63, 0.14) | 9.22 (−1.15, 19.59) |
| Age2 | −0.01 (−0.09, 0.07) | −0.09 (−0.16, −0.02) | 0.013 (0.004, 0.022) | −0.09 (−0.19, 0.01) |
| Sex (ref.: female) | 97.34 (64.00, 130.68) | 41.78 (12.32, 71.24) | 7.22 (3.43, 11.02) | 146.35 (102.01, 190.68) |
| p-value (Age2) | 0.83 | 0.01 | 0.005 | 0.09 |
a.
ref.: reference group.
b.
LRT: likelihood ratio test, for testing the non-linear the association between age and dependent variables.