Results of linear regression of the susceptibility value on the control group with age and sex as independent variables
| ROI | Intercept /10−2 ppm | Age /10−3 ppm | Sex /10−3 ppm | P Value of Age | P Value of Sex |
|---|---|---|---|---|---|
| PT | 0.45 | 0.51 | 1.15 | .002 | .346 |
| GP | 7.22 | 0.18 | 8.26 | .729 | .057 |
| CN | 1.55 | 0.18 | 0.30 | .338 | .837 |
| DN | 1.60 | 1.10 | 8.68 | .017 | .018 |
| SN | 4.35 | 1.22 | −3.49 | .044 | .455 |
| RN | 1.26 | 1.72 | 1.07 | .014 | .841 |
| CP | 3.83 | −0.341 | 9.75 | .763 | .284 |
Note:—Significant positive age effect on susceptibility value was found in PT, DN, SN, and RN, suggesting higher level of iron concentration with increasing age. In the DN, significantly higher susceptibility value was found in women compared with men after controlling for the effect of age. In other regions except for the SN, the susceptibility value was also higher in women, though these differences were not statistically significant. These findings suggest that in the majority of brain regions, iron concentration increases with age and is higher among women.
SD indicates standard deviation; PT, putamen; GP, globus pallidus; CN, caudate nucleus; DN, dentate nucleus; SN, substantia nigra; RN, red nucleus; CP, choroid plexus.