Table 1. Sociodemographic Features and General Brain Morphology of the Three Genotype Groups.
| AA | AG | GG | P | |
|---|---|---|---|---|
| Subjects | 155 | 172 | 33 | |
| Sex (male/female) | 79/76 | 84/88 | 23/10 | 0.087 |
| Handedness (right/left) | 144/11 | 158/14 | 30/3 | 0.839 |
| Age (years) | 19.41±1.06 | 19.39±1.14 | 19.47±0.99 | 0.934 |
| School education (years) | 12.34±0.71 | 12.33±0.86 | 12.30±0.88 | 0.968 |
| Full-scale intelligence quotient | 109.68±11.52 | 109.27±11.31 | 111.45±9.96 | 0.594 |
| Working memory performance (2-back condition) | 89.61±5.77 | 89.04±6.27 | 88.15±7.75 | 0.418 |
| Working memory performance (3-back condition) | 82.19±6.44 | 82.34±6.78 | 78.35±7.30 | 0.006 |
| Gray-matter volume (GMV) | 715.40±61.39 | 711.03±60.72 | 726.85±63.13 | 0.383 |
| White-matter volume (WMV) | 501.36±56.42 | 502.94±59.70 | 523.72±57.17 | 0.125 |
| CSF volume (CSFV) | 207.12±26.47 | 208.70±27.94 | 209.00±22.78 | 0.850 |
| Total intracranial volume (TIV) | 1423.88±129.50 | 1422.67±133.34 | 1459.56±127.95 | 0.317 |
| Normalized GMVa | 0.5029±0.0153 | 0.5004±0.0159 | 0.4982±0.0150 | 0.185 |
| Normalized WMVa | 0.3517±0.0156 | 0.3530±0.0168 | 0.3584±0.0160 | 0.098 |
| Normalized CSFVa | 0.1454±0.0123 | 0.1466±0.0123 | 0.1434±0.0115 | 0.337 |
| APOE status (APOEɛ4−/+) | 133/22 | 139/33 | 30/3 | 0.538 |
Values denote mean±standard deviation or number of subjects; P-values refer to one-way ANOVAs (parametric data) and Fisher–Freeman–Halton exact tests (categorical data).
a
The normalization of tissue volumes was calculated by dividing the GM, WM, and CSF volume by the TIV.